includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 /**
  26  * Represents a title within MediaWiki.
  27  * Optionally may contain an interwiki designation or namespace.
  28  * @note This class can fetch various kinds of data from the database;
  29  *       however, it does so inefficiently.
  30  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  31  *       and does not rely on global state or the database.
  32  */
  33 class Title {
  34         /** @var MapCacheLRU */
  35         static private $titleCache = null;
  36
  37         /**
  38          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  39          * commonly used titles. On a batch operation this can become a memory leak
  40          * if not bounded. After hitting this many titles reset the cache.
  41          */
  42         const CACHE_MAX = 1000;
  43
  44         /**
  45          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  46          * to use the master DB
  47          */
  48         const GAID_FOR_UPDATE = 1;
  49
  50         /**
  51          * @name Private member variables
  52          * Please use the accessor functions instead.
  53          * @private
  54          */
  55         // @{
  56
  57         /** @var string Text form (spaces not underscores) of the main part */
  58         public $mTextform = '';
  59
  60         /** @var string URL-encoded form of the main part */
  61         public $mUrlform = '';
  62
  63         /** @var string Main part with underscores */
  64         public $mDbkeyform = '';
  65
  66         /** @var string Database key with the initial letter in the case specified by the user */
  67         protected $mUserCaseDBKey;
  68
  69         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  70         public $mNamespace = NS_MAIN;
  71
  72         /** @var string Interwiki prefix */
  73         public $mInterwiki = '';
  74
  75         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  76         private $mLocalInterwiki = false;
  77
  78         /** @var string Title fragment (i.e. the bit after the #) */
  79         public $mFragment = '';
  80
  81         /** @var int Article ID, fetched from the link cache on demand */
  82         public $mArticleID = -1;
  83
  84         /** @var bool|int ID of most recent revision */
  85         protected $mLatestID = false;
  86
  87         /**
  88          * @var bool|string ID of the page's content model, i.e. one of the
  89          *   CONTENT_MODEL_XXX constants
  90          */
  91         public $mContentModel = false;
  92
  93         /** @var int Estimated number of revisions; null of not loaded */
  94         private $mEstimateRevisions;
  95
  96         /** @var array Array of groups allowed to edit this article */
  97         public $mRestrictions = array();
  98
  99         /** @var string|bool */
 100         protected $mOldRestrictions = false;
 101
 102         /** @var bool Cascade restrictions on this page to included templates and images? */
 103         public $mCascadeRestriction;
 104
 105         /** Caching the results of getCascadeProtectionSources */
 106         public $mCascadingRestrictions;
 107
 108         /** @var array When do the restrictions on this page expire? */
 109         protected $mRestrictionsExpiry = array();
 110
 111         /** @var bool Are cascading restrictions in effect on this page? */
 112         protected $mHasCascadingRestrictions;
 113
 114         /** @var array Where are the cascading restrictions coming from on this page? */
 115         public $mCascadeSources;
 116
 117         /** @var bool Boolean for initialisation on demand */
 118         public $mRestrictionsLoaded = false;
 119
 120         /** @var string Text form including namespace/interwiki, initialised on demand */
 121         protected $mPrefixedText = null;
 122
 123         /** @var mixed Cached value for getTitleProtection (create protection) */
 124         public $mTitleProtection;
 125
 126         /**
 127          * @var int Namespace index when there is no namespace. Don't change the
 128          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 129          *   Zero except in {{transclusion}} tags.
 130          */
 131         public $mDefaultNamespace = NS_MAIN;
 132
 133         /**
 134          * @var bool Is $wgUser watching this page? null if unfilled, accessed
 135          * through userIsWatching()
 136          */
 137         protected $mWatched = null;
 138
 139         /** @var int The page length, 0 for special pages */
 140         protected $mLength = -1;
 141
 142         /** @var null Is the article at this title a redirect? */
 143         public $mRedirect = null;
 144
 145         /** @var array Associative array of user ID -> timestamp/false */
 146         private $mNotificationTimestamp = array();
 147
 148         /** @var bool Whether a page has any subpages */
 149         private $mHasSubpages;
 150
 151         /** @var bool The (string) language code of the page's language and content code. */
 152         private $mPageLanguage = false;
 153
 154         /** @var string The page language code from the database */
 155         private $mDbPageLanguage = null;
 156
 157         /** @var TitleValue A corresponding TitleValue object */
 158         private $mTitleValue = null;
 159
 160         /** @var bool Would deleting this page be a big deletion? */
 161         private $mIsBigDeletion = null;
 162         // @}
 163
 164         /**
 165          * B/C kludge: provide a TitleParser for use by Title.
 166          * Ideally, Title would have no methods that need this.
 167          * Avoid usage of this singleton by using TitleValue
 168          * and the associated services when possible.
 169          *
 170          * @return TitleParser
 171          */
 172         private static function getTitleParser() {
 173                 global $wgContLang, $wgLocalInterwikis;
 174
 175                 static $titleCodec = null;
 176                 static $titleCodecFingerprint = null;
 177
 178                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 179                 // make sure we are using the right one. To detect changes over the course
 180                 // of a request, we remember a fingerprint of the config used to create the
 181                 // codec singleton, and re-create it if the fingerprint doesn't match.
 182                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . join( '+', $wgLocalInterwikis );
 183
 184                 if ( $fingerprint !== $titleCodecFingerprint ) {
 185                         $titleCodec = null;
 186                 }
 187
 188                 if ( !$titleCodec ) {
 189                         $titleCodec = new MediaWikiTitleCodec(
 190                                 $wgContLang,
 191                                 GenderCache::singleton(),
 192                                 $wgLocalInterwikis
 193                         );
 194                         $titleCodecFingerprint = $fingerprint;
 195                 }
 196
 197                 return $titleCodec;
 198         }
 199
 200         /**
 201          * B/C kludge: provide a TitleParser for use by Title.
 202          * Ideally, Title would have no methods that need this.
 203          * Avoid usage of this singleton by using TitleValue
 204          * and the associated services when possible.
 205          *
 206          * @return TitleFormatter
 207          */
 208         private static function getTitleFormatter() {
 209                 //NOTE: we know that getTitleParser() returns a MediaWikiTitleCodec,
 210                 //      which implements TitleFormatter.
 211                 return self::getTitleParser();
 212         }
 213
 214         function __construct() {
 215         }
 216
 217         /**
 218          * Create a new Title from a prefixed DB key
 219          *
 220          * @param string $key The database key, which has underscores
 221          *      instead of spaces, possibly including namespace and
 222          *      interwiki prefixes
 223          * @return Title|null Title, or null on an error
 224          */
 225         public static function newFromDBkey( $key ) {
 226                 $t = new Title();
 227                 $t->mDbkeyform = $key;
 228
 229                 try {
 230                         $t->secureAndSplit();
 231                         return $t;
 232                 } catch ( MalformedTitleException $ex ) {
 233                         return null;
 234                 }
 235         }
 236
 237         /**
 238          * Create a new Title from a TitleValue
 239          *
 240          * @param TitleValue $titleValue Assumed to be safe.
 241          *
 242          * @return Title
 243          */
 244         public static function newFromTitleValue( TitleValue $titleValue ) {
 245                 return self::makeTitle(
 246                         $titleValue->getNamespace(),
 247                         $titleValue->getText(),
 248                         $titleValue->getFragment() );
 249         }
 250
 251         /**
 252          * Create a new Title from text, such as what one would find in a link. De-
 253          * codes any HTML entities in the text.
 254          *
 255          * @param string $text The link text; spaces, prefixes, and an
 256          *   initial ':' indicating the main namespace are accepted.
 257          * @param int $defaultNamespace The namespace to use if none is specified
 258          *   by a prefix.  If you want to force a specific namespace even if
 259          *   $text might begin with a namespace prefix, use makeTitle() or
 260          *   makeTitleSafe().
 261          * @throws InvalidArgumentException
 262          * @return Title|null Title or null on an error.
 263          */
 264         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 265                 if ( is_object( $text ) ) {
 266                         throw new InvalidArgumentException( '$text must be a string.' );
 267                 } elseif ( !is_string( $text ) ) {
 268                         wfWarn( __METHOD__ . ': $text must be a string. This will throw an InvalidArgumentException in future.', 2 );
 269                 }
 270
 271                 try {
 272                         return Title::newFromTextThrow( $text, $defaultNamespace );
 273                 } catch ( MalformedTitleException $ex ) {
 274                         return null;
 275                 }
 276         }
 277
 278         /**
 279          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 280          * rather than returning null.
 281          *
 282          * The exception subclasses encode detailed information about why the title is invalid.
 283          *
 284          * @see Title::newFromText
 285          *
 286          * @since 1.25
 287          * @param string $text Title text to check
 288          * @param int $defaultNamespace
 289          * @throws MalformedTitleException If the title is invalid
 290          * @return Title
 291          */
 292         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 293                 if ( is_object( $text ) ) {
 294                         throw new MWException( 'Title::newFromTextThrow given an object' );
 295                 }
 296
 297                 $cache = self::getTitleCache();
 298
 299                 /**
 300                  * Wiki pages often contain multiple links to the same page.
 301                  * Title normalization and parsing can become expensive on
 302                  * pages with many links, so we can save a little time by
 303                  * caching them.
 304                  *
 305                  * In theory these are value objects and won't get changed...
 306                  */
 307                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 308                         return $cache->get( $text );
 309                 }
 310
 311                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 312                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 313
 314                 $t = new Title();
 315                 $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
 316                 $t->mDefaultNamespace = intval( $defaultNamespace );
 317
 318                 $t->secureAndSplit();
 319                 if ( $defaultNamespace == NS_MAIN ) {
 320                         $cache->set( $text, $t );
 321                 }
 322                 return $t;
 323         }
 324
 325         /**
 326          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 327          *
 328          * Example of wrong and broken code:
 329          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 330          *
 331          * Example of right code:
 332          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 333          *
 334          * Create a new Title from URL-encoded text. Ensures that
 335          * the given title's length does not exceed the maximum.
 336          *
 337          * @param string $url The title, as might be taken from a URL
 338          * @return Title|null The new object, or null on an error
 339          */
 340         public static function newFromURL( $url ) {
 341                 $t = new Title();
 342
 343                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 344                 # but some URLs used it as a space replacement and they still come
 345                 # from some external search tools.
 346                 if ( strpos( self::legalChars(), '+' ) === false ) {
 347                         $url = str_replace( '+', ' ', $url );
 348                 }
 349
 350                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 351
 352                 try {
 353                         $t->secureAndSplit();
 354                         return $t;
 355                 } catch ( MalformedTitleException $ex ) {
 356                         return null;
 357                 }
 358         }
 359
 360         /**
 361          * @return MapCacheLRU
 362          */
 363         private static function getTitleCache() {
 364                 if ( self::$titleCache == null ) {
 365                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 366                 }
 367                 return self::$titleCache;
 368         }
 369
 370         /**
 371          * Returns a list of fields that are to be selected for initializing Title
 372          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 373          * whether to include page_content_model.
 374          *
 375          * @return array
 376          */
 377         protected static function getSelectFields() {
 378                 global $wgContentHandlerUseDB;
 379
 380                 $fields = array(
 381                         'page_namespace', 'page_title', 'page_id',
 382                         'page_len', 'page_is_redirect', 'page_latest',
 383                 );
 384
 385                 if ( $wgContentHandlerUseDB ) {
 386                         $fields[] = 'page_content_model';
 387                 }
 388
 389                 return $fields;
 390         }
 391
 392         /**
 393          * Create a new Title from an article ID
 394          *
 395          * @param int $id The page_id corresponding to the Title to create
 396          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 397          * @return Title|null The new object, or null on an error
 398          */
 399         public static function newFromID( $id, $flags = 0 ) {
 400                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 401                 $row = $db->selectRow(
 402                         'page',
 403                         self::getSelectFields(),
 404                         array( 'page_id' => $id ),
 405                         __METHOD__
 406                 );
 407                 if ( $row !== false ) {
 408                         $title = Title::newFromRow( $row );
 409                 } else {
 410                         $title = null;
 411                 }
 412                 return $title;
 413         }
 414
 415         /**
 416          * Make an array of titles from an array of IDs
 417          *
 418          * @param int[] $ids Array of IDs
 419          * @return Title[] Array of Titles
 420          */
 421         public static function newFromIDs( $ids ) {
 422                 if ( !count( $ids ) ) {
 423                         return array();
 424                 }
 425                 $dbr = wfGetDB( DB_SLAVE );
 426
 427                 $res = $dbr->select(
 428                         'page',
 429                         self::getSelectFields(),
 430                         array( 'page_id' => $ids ),
 431                         __METHOD__
 432                 );
 433
 434                 $titles = array();
 435                 foreach ( $res as $row ) {
 436                         $titles[] = Title::newFromRow( $row );
 437                 }
 438                 return $titles;
 439         }
 440
 441         /**
 442          * Make a Title object from a DB row
 443          *
 444          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 445          * @return Title Corresponding Title
 446          */
 447         public static function newFromRow( $row ) {
 448                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 449                 $t->loadFromRow( $row );
 450                 return $t;
 451         }
 452
 453         /**
 454          * Load Title object fields from a DB row.
 455          * If false is given, the title will be treated as non-existing.
 456          *
 457          * @param stdClass|bool $row Database row
 458          */
 459         public function loadFromRow( $row ) {
 460                 if ( $row ) { // page found
 461                         if ( isset( $row->page_id ) ) {
 462                                 $this->mArticleID = (int)$row->page_id;
 463                         }
 464                         if ( isset( $row->page_len ) ) {
 465                                 $this->mLength = (int)$row->page_len;
 466                         }
 467                         if ( isset( $row->page_is_redirect ) ) {
 468                                 $this->mRedirect = (bool)$row->page_is_redirect;
 469                         }
 470                         if ( isset( $row->page_latest ) ) {
 471                                 $this->mLatestID = (int)$row->page_latest;
 472                         }
 473                         if ( isset( $row->page_content_model ) ) {
 474                                 $this->mContentModel = strval( $row->page_content_model );
 475                         } else {
 476                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 477                         }
 478                         if ( isset( $row->page_lang ) ) {
 479                                 $this->mDbPageLanguage = (string)$row->page_lang;
 480                         }
 481                         if ( isset( $row->page_restrictions ) ) {
 482                                 $this->mOldRestrictions = $row->page_restrictions;
 483                         }
 484                 } else { // page not found
 485                         $this->mArticleID = 0;
 486                         $this->mLength = 0;
 487                         $this->mRedirect = false;
 488                         $this->mLatestID = 0;
 489                         $this->mContentModel = false; # initialized lazily in getContentModel()
 490                 }
 491         }
 492
 493         /**
 494          * Create a new Title from a namespace index and a DB key.
 495          * It's assumed that $ns and $title are *valid*, for instance when
 496          * they came directly from the database or a special page name.
 497          * For convenience, spaces are converted to underscores so that
 498          * eg user_text fields can be used directly.
 499          *
 500          * @param int $ns The namespace of the article
 501          * @param string $title The unprefixed database key form
 502          * @param string $fragment The link fragment (after the "#")
 503          * @param string $interwiki The interwiki prefix
 504          * @return Title The new object
 505          */
 506         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 507                 $t = new Title();
 508                 $t->mInterwiki = $interwiki;
 509                 $t->mFragment = $fragment;
 510                 $t->mNamespace = $ns = intval( $ns );
 511                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 512                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 513                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 514                 $t->mTextform = str_replace( '_', ' ', $title );
 515                 $t->mContentModel = false; # initialized lazily in getContentModel()
 516                 return $t;
 517         }
 518
 519         /**
 520          * Create a new Title from a namespace index and a DB key.
 521          * The parameters will be checked for validity, which is a bit slower
 522          * than makeTitle() but safer for user-provided data.
 523          *
 524          * @param int $ns The namespace of the article
 525          * @param string $title Database key form
 526          * @param string $fragment The link fragment (after the "#")
 527          * @param string $interwiki Interwiki prefix
 528          * @return Title The new object, or null on an error
 529          */
 530         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 531                 if ( !MWNamespace::exists( $ns ) ) {
 532                         return null;
 533                 }
 534
 535                 $t = new Title();
 536                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 537
 538                 try {
 539                         $t->secureAndSplit();
 540                         return $t;
 541                 } catch ( MalformedTitleException $ex ) {
 542                         return null;
 543                 }
 544         }
 545
 546         /**
 547          * Create a new Title for the Main Page
 548          *
 549          * @return Title The new object
 550          */
 551         public static function newMainPage() {
 552                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 553                 // Don't give fatal errors if the message is broken
 554                 if ( !$title ) {
 555                         $title = Title::newFromText( 'Main Page' );
 556                 }
 557                 return $title;
 558         }
 559
 560         /**
 561          * Extract a redirect destination from a string and return the
 562          * Title, or null if the text doesn't contain a valid redirect
 563          * This will only return the very next target, useful for
 564          * the redirect table and other checks that don't need full recursion
 565          *
 566          * @param string $text Text with possible redirect
 567          * @return Title The corresponding Title
 568          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 569          */
 570         public static function newFromRedirect( $text ) {
 571                 ContentHandler::deprecated( __METHOD__, '1.21' );
 572
 573                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 574                 return $content->getRedirectTarget();
 575         }
 576
 577         /**
 578          * Extract a redirect destination from a string and return the
 579          * Title, or null if the text doesn't contain a valid redirect
 580          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 581          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 582          *
 583          * @param string $text Text with possible redirect
 584          * @return Title
 585          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 586          */
 587         public static function newFromRedirectRecurse( $text ) {
 588                 ContentHandler::deprecated( __METHOD__, '1.21' );
 589
 590                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 591                 return $content->getUltimateRedirectTarget();
 592         }
 593
 594         /**
 595          * Extract a redirect destination from a string and return an
 596          * array of Titles, or null if the text doesn't contain a valid redirect
 597          * The last element in the array is the final destination after all redirects
 598          * have been resolved (up to $wgMaxRedirects times)
 599          *
 600          * @param string $text Text with possible redirect
 601          * @return Title[] Array of Titles, with the destination last
 602          * @deprecated since 1.21, use Content::getRedirectChain instead.
 603          */
 604         public static function newFromRedirectArray( $text ) {
 605                 ContentHandler::deprecated( __METHOD__, '1.21' );
 606
 607                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 608                 return $content->getRedirectChain();
 609         }
 610
 611         /**
 612          * Get the prefixed DB key associated with an ID
 613          *
 614          * @param int $id The page_id of the article
 615          * @return Title|null An object representing the article, or null if no such article was found
 616          */
 617         public static function nameOf( $id ) {
 618                 $dbr = wfGetDB( DB_SLAVE );
 619
 620                 $s = $dbr->selectRow(
 621                         'page',
 622                         array( 'page_namespace', 'page_title' ),
 623                         array( 'page_id' => $id ),
 624                         __METHOD__
 625                 );
 626                 if ( $s === false ) {
 627                         return null;
 628                 }
 629
 630                 $n = self::makeName( $s->page_namespace, $s->page_title );
 631                 return $n;
 632         }
 633
 634         /**
 635          * Get a regex character class describing the legal characters in a link
 636          *
 637          * @return string The list of characters, not delimited
 638          */
 639         public static function legalChars() {
 640                 global $wgLegalTitleChars;
 641                 return $wgLegalTitleChars;
 642         }
 643
 644         /**
 645          * Returns a simple regex that will match on characters and sequences invalid in titles.
 646          * Note that this doesn't pick up many things that could be wrong with titles, but that
 647          * replacing this regex with something valid will make many titles valid.
 648          *
 649          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 650          *
 651          * @return string Regex string
 652          */
 653         static function getTitleInvalidRegex() {
 654                 wfDeprecated( __METHOD__, '1.25' );
 655                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 656         }
 657
 658         /**
 659          * Utility method for converting a character sequence from bytes to Unicode.
 660          *
 661          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 662          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 663          *
 664          * @param string $byteClass
 665          * @return string
 666          */
 667         public static function convertByteClassToUnicodeClass( $byteClass ) {
 668                 $length = strlen( $byteClass );
 669                 // Input token queue
 670                 $x0 = $x1 = $x2 = '';
 671                 // Decoded queue
 672                 $d0 = $d1 = $d2 = '';
 673                 // Decoded integer codepoints
 674                 $ord0 = $ord1 = $ord2 = 0;
 675                 // Re-encoded queue
 676                 $r0 = $r1 = $r2 = '';
 677                 // Output
 678                 $out = '';
 679                 // Flags
 680                 $allowUnicode = false;
 681                 for ( $pos = 0; $pos < $length; $pos++ ) {
 682                         // Shift the queues down
 683                         $x2 = $x1;
 684                         $x1 = $x0;
 685                         $d2 = $d1;
 686                         $d1 = $d0;
 687                         $ord2 = $ord1;
 688                         $ord1 = $ord0;
 689                         $r2 = $r1;
 690                         $r1 = $r0;
 691                         // Load the current input token and decoded values
 692                         $inChar = $byteClass[$pos];
 693                         if ( $inChar == '\\' ) {
 694                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 695                                         $x0 = $inChar . $m[0];
 696                                         $d0 = chr( hexdec( $m[1] ) );
 697                                         $pos += strlen( $m[0] );
 698                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 699                                         $x0 = $inChar . $m[0];
 700                                         $d0 = chr( octdec( $m[0] ) );
 701                                         $pos += strlen( $m[0] );
 702                                 } elseif ( $pos + 1 >= $length ) {
 703                                         $x0 = $d0 = '\\';
 704                                 } else {
 705                                         $d0 = $byteClass[$pos + 1];
 706                                         $x0 = $inChar . $d0;
 707                                         $pos += 1;
 708                                 }
 709                         } else {
 710                                 $x0 = $d0 = $inChar;
 711                         }
 712                         $ord0 = ord( $d0 );
 713                         // Load the current re-encoded value
 714                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 715                                 $r0 = sprintf( '\x%02x', $ord0 );
 716                         } elseif ( $ord0 >= 0x80 ) {
 717                                 // Allow unicode if a single high-bit character appears
 718                                 $r0 = sprintf( '\x%02x', $ord0 );
 719                                 $allowUnicode = true;
 720                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 721                                 $r0 = '\\' . $d0;
 722                         } else {
 723                                 $r0 = $d0;
 724                         }
 725                         // Do the output
 726                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 727                                 // Range
 728                                 if ( $ord2 > $ord0 ) {
 729                                         // Empty range
 730                                 } elseif ( $ord0 >= 0x80 ) {
 731                                         // Unicode range
 732                                         $allowUnicode = true;
 733                                         if ( $ord2 < 0x80 ) {
 734                                                 // Keep the non-unicode section of the range
 735                                                 $out .= "$r2-\\x7F";
 736                                         }
 737                                 } else {
 738                                         // Normal range
 739                                         $out .= "$r2-$r0";
 740                                 }
 741                                 // Reset state to the initial value
 742                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 743                         } elseif ( $ord2 < 0x80 ) {
 744                                 // ASCII character
 745                                 $out .= $r2;
 746                         }
 747                 }
 748                 if ( $ord1 < 0x80 ) {
 749                         $out .= $r1;
 750                 }
 751                 if ( $ord0 < 0x80 ) {
 752                         $out .= $r0;
 753                 }
 754                 if ( $allowUnicode ) {
 755                         $out .= '\u0080-\uFFFF';
 756                 }
 757                 return $out;
 758         }
 759
 760         /**
 761          * Make a prefixed DB key from a DB key and a namespace index
 762          *
 763          * @param int $ns Numerical representation of the namespace
 764          * @param string $title The DB key form the title
 765          * @param string $fragment The link fragment (after the "#")
 766          * @param string $interwiki The interwiki prefix
 767          * @param bool $canoncialNamespace If true, use the canonical name for
 768          *   $ns instead of the localized version.
 769          * @return string The prefixed form of the title
 770          */
 771         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 772                 $canoncialNamespace = false
 773         ) {
 774                 global $wgContLang;
 775
 776                 if ( $canoncialNamespace ) {
 777                         $namespace = MWNamespace::getCanonicalName( $ns );
 778                 } else {
 779                         $namespace = $wgContLang->getNsText( $ns );
 780                 }
 781                 $name = $namespace == '' ? $title : "$namespace:$title";
 782                 if ( strval( $interwiki ) != '' ) {
 783                         $name = "$interwiki:$name";
 784                 }
 785                 if ( strval( $fragment ) != '' ) {
 786                         $name .= '#' . $fragment;
 787                 }
 788                 return $name;
 789         }
 790
 791         /**
 792          * Escape a text fragment, say from a link, for a URL
 793          *
 794          * @param string $fragment Containing a URL or link fragment (after the "#")
 795          * @return string Escaped string
 796          */
 797         static function escapeFragmentForURL( $fragment ) {
 798                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 799                 # fragments appear not to work in IE (at least up to 7) or in at least
 800                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 801                 # to care if they aren't encoded.
 802                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 803         }
 804
 805         /**
 806          * Callback for usort() to do title sorts by (namespace, title)
 807          *
 808          * @param Title $a
 809          * @param Title $b
 810          *
 811          * @return int Result of string comparison, or namespace comparison
 812          */
 813         public static function compare( $a, $b ) {
 814                 if ( $a->getNamespace() == $b->getNamespace() ) {
 815                         return strcmp( $a->getText(), $b->getText() );
 816                 } else {
 817                         return $a->getNamespace() - $b->getNamespace();
 818                 }
 819         }
 820
 821         /**
 822          * Determine whether the object refers to a page within
 823          * this project (either this wiki or a wiki with a local
 824          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 825          *
 826          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 827          */
 828         public function isLocal() {
 829                 if ( $this->isExternal() ) {
 830                         $iw = Interwiki::fetch( $this->mInterwiki );
 831                         if ( $iw ) {
 832                                 return $iw->isLocal();
 833                         }
 834                 }
 835                 return true;
 836         }
 837
 838         /**
 839          * Is this Title interwiki?
 840          *
 841          * @return bool
 842          */
 843         public function isExternal() {
 844                 return $this->mInterwiki !== '';
 845         }
 846
 847         /**
 848          * Get the interwiki prefix
 849          *
 850          * Use Title::isExternal to check if a interwiki is set
 851          *
 852          * @return string Interwiki prefix
 853          */
 854         public function getInterwiki() {
 855                 return $this->mInterwiki;
 856         }
 857
 858         /**
 859          * Was this a local interwiki link?
 860          *
 861          * @return bool
 862          */
 863         public function wasLocalInterwiki() {
 864                 return $this->mLocalInterwiki;
 865         }
 866
 867         /**
 868          * Determine whether the object refers to a page within
 869          * this project and is transcludable.
 870          *
 871          * @return bool True if this is transcludable
 872          */
 873         public function isTrans() {
 874                 if ( !$this->isExternal() ) {
 875                         return false;
 876                 }
 877
 878                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 879         }
 880
 881         /**
 882          * Returns the DB name of the distant wiki which owns the object.
 883          *
 884          * @return string The DB name
 885          */
 886         public function getTransWikiID() {
 887                 if ( !$this->isExternal() ) {
 888                         return false;
 889                 }
 890
 891                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 892         }
 893
 894         /**
 895          * Get a TitleValue object representing this Title.
 896          *
 897          * @note Not all valid Titles have a corresponding valid TitleValue
 898          * (e.g. TitleValues cannot represent page-local links that have a
 899          * fragment but no title text).
 900          *
 901          * @return TitleValue|null
 902          */
 903         public function getTitleValue() {
 904                 if ( $this->mTitleValue === null ) {
 905                         try {
 906                                 $this->mTitleValue = new TitleValue(
 907                                         $this->getNamespace(),
 908                                         $this->getDBkey(),
 909                                         $this->getFragment() );
 910                         } catch ( InvalidArgumentException $ex ) {
 911                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 912                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 913                         }
 914                 }
 915
 916                 return $this->mTitleValue;
 917         }
 918
 919         /**
 920          * Get the text form (spaces not underscores) of the main part
 921          *
 922          * @return string Main part of the title
 923          */
 924         public function getText() {
 925                 return $this->mTextform;
 926         }
 927
 928         /**
 929          * Get the URL-encoded form of the main part
 930          *
 931          * @return string Main part of the title, URL-encoded
 932          */
 933         public function getPartialURL() {
 934                 return $this->mUrlform;
 935         }
 936
 937         /**
 938          * Get the main part with underscores
 939          *
 940          * @return string Main part of the title, with underscores
 941          */
 942         public function getDBkey() {
 943                 return $this->mDbkeyform;
 944         }
 945
 946         /**
 947          * Get the DB key with the initial letter case as specified by the user
 948          *
 949          * @return string DB key
 950          */
 951         function getUserCaseDBKey() {
 952                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 953                         return $this->mUserCaseDBKey;
 954                 } else {
 955                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 956                         return $this->mDbkeyform;
 957                 }
 958         }
 959
 960         /**
 961          * Get the namespace index, i.e. one of the NS_xxxx constants.
 962          *
 963          * @return int Namespace index
 964          */
 965         public function getNamespace() {
 966                 return $this->mNamespace;
 967         }
 968
 969         /**
 970          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 971          *
 972          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 973          * @return string Content model id
 974          */
 975         public function getContentModel( $flags = 0 ) {
 976                 if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 977                         $linkCache = LinkCache::singleton();
 978                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 979                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 980                 }
 981
 982                 if ( !$this->mContentModel ) {
 983                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 984                 }
 985
 986                 return $this->mContentModel;
 987         }
 988
 989         /**
 990          * Convenience method for checking a title's content model name
 991          *
 992          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 993          * @return bool True if $this->getContentModel() == $id
 994          */
 995         public function hasContentModel( $id ) {
 996                 return $this->getContentModel() == $id;
 997         }
 998
 999         /**
1000          * Get the namespace text
1001          *
1002          * @return string Namespace text
1003          */
1004         public function getNsText() {
1005                 if ( $this->isExternal() ) {
1006                         // This probably shouldn't even happen. ohh man, oh yuck.
1007                         // But for interwiki transclusion it sometimes does.
1008                         // Shit. Shit shit shit.
1009                         //
1010                         // Use the canonical namespaces if possible to try to
1011                         // resolve a foreign namespace.
1012                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1013                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1014                         }
1015                 }
1016
1017                 try {
1018                         $formatter = self::getTitleFormatter();
1019                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1020                 } catch ( InvalidArgumentException $ex ) {
1021                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1022                         return false;
1023                 }
1024         }
1025
1026         /**
1027          * Get the namespace text of the subject (rather than talk) page
1028          *
1029          * @return string Namespace text
1030          */
1031         public function getSubjectNsText() {
1032                 global $wgContLang;
1033                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1034         }
1035
1036         /**
1037          * Get the namespace text of the talk page
1038          *
1039          * @return string Namespace text
1040          */
1041         public function getTalkNsText() {
1042                 global $wgContLang;
1043                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1044         }
1045
1046         /**
1047          * Could this title have a corresponding talk page?
1048          *
1049          * @return bool
1050          */
1051         public function canTalk() {
1052                 return MWNamespace::canTalk( $this->mNamespace );
1053         }
1054
1055         /**
1056          * Is this in a namespace that allows actual pages?
1057          *
1058          * @return bool
1059          */
1060         public function canExist() {
1061                 return $this->mNamespace >= NS_MAIN;
1062         }
1063
1064         /**
1065          * Can this title be added to a user's watchlist?
1066          *
1067          * @return bool
1068          */
1069         public function isWatchable() {
1070                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1071         }
1072
1073         /**
1074          * Returns true if this is a special page.
1075          *
1076          * @return bool
1077          */
1078         public function isSpecialPage() {
1079                 return $this->getNamespace() == NS_SPECIAL;
1080         }
1081
1082         /**
1083          * Returns true if this title resolves to the named special page
1084          *
1085          * @param string $name The special page name
1086          * @return bool
1087          */
1088         public function isSpecial( $name ) {
1089                 if ( $this->isSpecialPage() ) {
1090                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1091                         if ( $name == $thisName ) {
1092                                 return true;
1093                         }
1094                 }
1095                 return false;
1096         }
1097
1098         /**
1099          * If the Title refers to a special page alias which is not the local default, resolve
1100          * the alias, and localise the name as necessary.  Otherwise, return $this
1101          *
1102          * @return Title
1103          */
1104         public function fixSpecialName() {
1105                 if ( $this->isSpecialPage() ) {
1106                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1107                         if ( $canonicalName ) {
1108                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1109                                 if ( $localName != $this->mDbkeyform ) {
1110                                         return Title::makeTitle( NS_SPECIAL, $localName );
1111                                 }
1112                         }
1113                 }
1114                 return $this;
1115         }
1116
1117         /**
1118          * Returns true if the title is inside the specified namespace.
1119          *
1120          * Please make use of this instead of comparing to getNamespace()
1121          * This function is much more resistant to changes we may make
1122          * to namespaces than code that makes direct comparisons.
1123          * @param int $ns The namespace
1124          * @return bool
1125          * @since 1.19
1126          */
1127         public function inNamespace( $ns ) {
1128                 return MWNamespace::equals( $this->getNamespace(), $ns );
1129         }
1130
1131         /**
1132          * Returns true if the title is inside one of the specified namespaces.
1133          *
1134          * @param int $namespaces,... The namespaces to check for
1135          * @return bool
1136          * @since 1.19
1137          */
1138         public function inNamespaces( /* ... */ ) {
1139                 $namespaces = func_get_args();
1140                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1141                         $namespaces = $namespaces[0];
1142                 }
1143
1144                 foreach ( $namespaces as $ns ) {
1145                         if ( $this->inNamespace( $ns ) ) {
1146                                 return true;
1147                         }
1148                 }
1149
1150                 return false;
1151         }
1152
1153         /**
1154          * Returns true if the title has the same subject namespace as the
1155          * namespace specified.
1156          * For example this method will take NS_USER and return true if namespace
1157          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1158          * as their subject namespace.
1159          *
1160          * This is MUCH simpler than individually testing for equivalence
1161          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1162          * @since 1.19
1163          * @param int $ns
1164          * @return bool
1165          */
1166         public function hasSubjectNamespace( $ns ) {
1167                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1168         }
1169
1170         /**
1171          * Is this Title in a namespace which contains content?
1172          * In other words, is this a content page, for the purposes of calculating
1173          * statistics, etc?
1174          *
1175          * @return bool
1176          */
1177         public function isContentPage() {
1178                 return MWNamespace::isContent( $this->getNamespace() );
1179         }
1180
1181         /**
1182          * Would anybody with sufficient privileges be able to move this page?
1183          * Some pages just aren't movable.
1184          *
1185          * @return bool
1186          */
1187         public function isMovable() {
1188                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1189                         // Interwiki title or immovable namespace. Hooks don't get to override here
1190                         return false;
1191                 }
1192
1193                 $result = true;
1194                 Hooks::run( 'TitleIsMovable', array( $this, &$result ) );
1195                 return $result;
1196         }
1197
1198         /**
1199          * Is this the mainpage?
1200          * @note Title::newFromText seems to be sufficiently optimized by the title
1201          * cache that we don't need to over-optimize by doing direct comparisons and
1202          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1203          * ends up reporting something differently than $title->isMainPage();
1204          *
1205          * @since 1.18
1206          * @return bool
1207          */
1208         public function isMainPage() {
1209                 return $this->equals( Title::newMainPage() );
1210         }
1211
1212         /**
1213          * Is this a subpage?
1214          *
1215          * @return bool
1216          */
1217         public function isSubpage() {
1218                 return MWNamespace::hasSubpages( $this->mNamespace )
1219                         ? strpos( $this->getText(), '/' ) !== false
1220                         : false;
1221         }
1222
1223         /**
1224          * Is this a conversion table for the LanguageConverter?
1225          *
1226          * @return bool
1227          */
1228         public function isConversionTable() {
1229                 // @todo ConversionTable should become a separate content model.
1230
1231                 return $this->getNamespace() == NS_MEDIAWIKI &&
1232                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1233         }
1234
1235         /**
1236          * Does that page contain wikitext, or it is JS, CSS or whatever?
1237          *
1238          * @return bool
1239          */
1240         public function isWikitextPage() {
1241                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1242         }
1243
1244         /**
1245          * Could this page contain custom CSS or JavaScript for the global UI.
1246          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1247          * or CONTENT_MODEL_JAVASCRIPT.
1248          *
1249          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1250          * for that!
1251          *
1252          * Note that this method should not return true for pages that contain and
1253          * show "inactive" CSS or JS.
1254          *
1255          * @return bool
1256          */
1257         public function isCssOrJsPage() {
1258                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1259                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1260                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1261
1262                 # @note This hook is also called in ContentHandler::getDefaultModel.
1263                 #   It's called here again to make sure hook functions can force this
1264                 #   method to return true even outside the MediaWiki namespace.
1265
1266                 Hooks::run( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ), '1.25' );
1267
1268                 return $isCssOrJsPage;
1269         }
1270
1271         /**
1272          * Is this a .css or .js subpage of a user page?
1273          * @return bool
1274          */
1275         public function isCssJsSubpage() {
1276                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1277                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1278                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1279         }
1280
1281         /**
1282          * Trim down a .css or .js subpage title to get the corresponding skin name
1283          *
1284          * @return string Containing skin name from .css or .js subpage title
1285          */
1286         public function getSkinFromCssJsSubpage() {
1287                 $subpage = explode( '/', $this->mTextform );
1288                 $subpage = $subpage[count( $subpage ) - 1];
1289                 $lastdot = strrpos( $subpage, '.' );
1290                 if ( $lastdot === false ) {
1291                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1292                 }
1293                 return substr( $subpage, 0, $lastdot );
1294         }
1295
1296         /**
1297          * Is this a .css subpage of a user page?
1298          *
1299          * @return bool
1300          */
1301         public function isCssSubpage() {
1302                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1303                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1304         }
1305
1306         /**
1307          * Is this a .js subpage of a user page?
1308          *
1309          * @return bool
1310          */
1311         public function isJsSubpage() {
1312                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1313                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1314         }
1315
1316         /**
1317          * Is this a talk page of some sort?
1318          *
1319          * @return bool
1320          */
1321         public function isTalkPage() {
1322                 return MWNamespace::isTalk( $this->getNamespace() );
1323         }
1324
1325         /**
1326          * Get a Title object associated with the talk page of this article
1327          *
1328          * @return Title The object for the talk page
1329          */
1330         public function getTalkPage() {
1331                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1332         }
1333
1334         /**
1335          * Get a title object associated with the subject page of this
1336          * talk page
1337          *
1338          * @return Title The object for the subject page
1339          */
1340         public function getSubjectPage() {
1341                 // Is this the same title?
1342                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1343                 if ( $this->getNamespace() == $subjectNS ) {
1344                         return $this;
1345                 }
1346                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1347         }
1348
1349         /**
1350          * Get the other title for this page, if this is a subject page
1351          * get the talk page, if it is a subject page get the talk page
1352          *
1353          * @since 1.25
1354          * @throws MWException
1355          * @return Title
1356          */
1357         public function getOtherPage() {
1358                 if ( $this->isSpecialPage() ) {
1359                         throw new MWException( 'Special pages cannot have other pages' );
1360                 }
1361                 if ( $this->isTalkPage() ) {
1362                         return $this->getSubjectPage();
1363                 } else {
1364                         return $this->getTalkPage();
1365                 }
1366         }
1367
1368         /**
1369          * Get the default namespace index, for when there is no namespace
1370          *
1371          * @return int Default namespace index
1372          */
1373         public function getDefaultNamespace() {
1374                 return $this->mDefaultNamespace;
1375         }
1376
1377         /**
1378          * Get the Title fragment (i.e.\ the bit after the #) in text form
1379          *
1380          * Use Title::hasFragment to check for a fragment
1381          *
1382          * @return string Title fragment
1383          */
1384         public function getFragment() {
1385                 return $this->mFragment;
1386         }
1387
1388         /**
1389          * Check if a Title fragment is set
1390          *
1391          * @return bool
1392          * @since 1.23
1393          */
1394         public function hasFragment() {
1395                 return $this->mFragment !== '';
1396         }
1397
1398         /**
1399          * Get the fragment in URL form, including the "#" character if there is one
1400          * @return string Fragment in URL form
1401          */
1402         public function getFragmentForURL() {
1403                 if ( !$this->hasFragment() ) {
1404                         return '';
1405                 } else {
1406                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1407                 }
1408         }
1409
1410         /**
1411          * Set the fragment for this title. Removes the first character from the
1412          * specified fragment before setting, so it assumes you're passing it with
1413          * an initial "#".
1414          *
1415          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1416          * Still in active use privately.
1417          *
1418          * @param string $fragment Text
1419          */
1420         public function setFragment( $fragment ) {
1421                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1422         }
1423
1424         /**
1425          * Prefix some arbitrary text with the namespace or interwiki prefix
1426          * of this object
1427          *
1428          * @param string $name The text
1429          * @return string The prefixed text
1430          */
1431         private function prefix( $name ) {
1432                 $p = '';
1433                 if ( $this->isExternal() ) {
1434                         $p = $this->mInterwiki . ':';
1435                 }
1436
1437                 if ( 0 != $this->mNamespace ) {
1438                         $p .= $this->getNsText() . ':';
1439                 }
1440                 return $p . $name;
1441         }
1442
1443         /**
1444          * Get the prefixed database key form
1445          *
1446          * @return string The prefixed title, with underscores and
1447          *  any interwiki and namespace prefixes
1448          */
1449         public function getPrefixedDBkey() {
1450                 $s = $this->prefix( $this->mDbkeyform );
1451                 $s = str_replace( ' ', '_', $s );
1452                 return $s;
1453         }
1454
1455         /**
1456          * Get the prefixed title with spaces.
1457          * This is the form usually used for display
1458          *
1459          * @return string The prefixed title, with spaces
1460          */
1461         public function getPrefixedText() {
1462                 if ( $this->mPrefixedText === null ) {
1463                         $s = $this->prefix( $this->mTextform );
1464                         $s = str_replace( '_', ' ', $s );
1465                         $this->mPrefixedText = $s;
1466                 }
1467                 return $this->mPrefixedText;
1468         }
1469
1470         /**
1471          * Return a string representation of this title
1472          *
1473          * @return string Representation of this title
1474          */
1475         public function __toString() {
1476                 return $this->getPrefixedText();
1477         }
1478
1479         /**
1480          * Get the prefixed title with spaces, plus any fragment
1481          * (part beginning with '#')
1482          *
1483          * @return string The prefixed title, with spaces and the fragment, including '#'
1484          */
1485         public function getFullText() {
1486                 $text = $this->getPrefixedText();
1487                 if ( $this->hasFragment() ) {
1488                         $text .= '#' . $this->getFragment();
1489                 }
1490                 return $text;
1491         }
1492
1493         /**
1494          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1495          *
1496          * @par Example:
1497          * @code
1498          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1499          * # returns: 'Foo'
1500          * @endcode
1501          *
1502          * @return string Root name
1503          * @since 1.20
1504          */
1505         public function getRootText() {
1506                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1507                         return $this->getText();
1508                 }
1509
1510                 return strtok( $this->getText(), '/' );
1511         }
1512
1513         /**
1514          * Get the root page name title, i.e. the leftmost part before any slashes
1515          *
1516          * @par Example:
1517          * @code
1518          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1519          * # returns: Title{User:Foo}
1520          * @endcode
1521          *
1522          * @return Title Root title
1523          * @since 1.20
1524          */
1525         public function getRootTitle() {
1526                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1527         }
1528
1529         /**
1530          * Get the base page name without a namespace, i.e. the part before the subpage name
1531          *
1532          * @par Example:
1533          * @code
1534          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1535          * # returns: 'Foo/Bar'
1536          * @endcode
1537          *
1538          * @return string Base name
1539          */
1540         public function getBaseText() {
1541                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1542                         return $this->getText();
1543                 }
1544
1545                 $parts = explode( '/', $this->getText() );
1546                 # Don't discard the real title if there's no subpage involved
1547                 if ( count( $parts ) > 1 ) {
1548                         unset( $parts[count( $parts ) - 1] );
1549                 }
1550                 return implode( '/', $parts );
1551         }
1552
1553         /**
1554          * Get the base page name title, i.e. the part before the subpage name
1555          *
1556          * @par Example:
1557          * @code
1558          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1559          * # returns: Title{User:Foo/Bar}
1560          * @endcode
1561          *
1562          * @return Title Base title
1563          * @since 1.20
1564          */
1565         public function getBaseTitle() {
1566                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1567         }
1568
1569         /**
1570          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1571          *
1572          * @par Example:
1573          * @code
1574          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1575          * # returns: "Baz"
1576          * @endcode
1577          *
1578          * @return string Subpage name
1579          */
1580         public function getSubpageText() {
1581                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1582                         return $this->mTextform;
1583                 }
1584                 $parts = explode( '/', $this->mTextform );
1585                 return $parts[count( $parts ) - 1];
1586         }
1587
1588         /**
1589          * Get the title for a subpage of the current page
1590          *
1591          * @par Example:
1592          * @code
1593          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1594          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1595          * @endcode
1596          *
1597          * @param string $text The subpage name to add to the title
1598          * @return Title Subpage title
1599          * @since 1.20
1600          */
1601         public function getSubpage( $text ) {
1602                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1603         }
1604
1605         /**
1606          * Get a URL-encoded form of the subpage text
1607          *
1608          * @return string URL-encoded subpage name
1609          */
1610         public function getSubpageUrlForm() {
1611                 $text = $this->getSubpageText();
1612                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1613                 return $text;
1614         }
1615
1616         /**
1617          * Get a URL-encoded title (not an actual URL) including interwiki
1618          *
1619          * @return string The URL-encoded form
1620          */
1621         public function getPrefixedURL() {
1622                 $s = $this->prefix( $this->mDbkeyform );
1623                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1624                 return $s;
1625         }
1626
1627         /**
1628          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1629          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1630          * second argument named variant. This was deprecated in favor
1631          * of passing an array of option with a "variant" key
1632          * Once $query2 is removed for good, this helper can be dropped
1633          * and the wfArrayToCgi moved to getLocalURL();
1634          *
1635          * @since 1.19 (r105919)
1636          * @param array|string $query
1637          * @param bool $query2
1638          * @return string
1639          */
1640         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1641                 if ( $query2 !== false ) {
1642                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1643                                 "method called with a second parameter is deprecated. Add your " .
1644                                 "parameter to an array passed as the first parameter.", "1.19" );
1645                 }
1646                 if ( is_array( $query ) ) {
1647                         $query = wfArrayToCgi( $query );
1648                 }
1649                 if ( $query2 ) {
1650                         if ( is_string( $query2 ) ) {
1651                                 // $query2 is a string, we will consider this to be
1652                                 // a deprecated $variant argument and add it to the query
1653                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1654                         } else {
1655                                 $query2 = wfArrayToCgi( $query2 );
1656                         }
1657                         // If we have $query content add a & to it first
1658                         if ( $query ) {
1659                                 $query .= '&';
1660                         }
1661                         // Now append the queries together
1662                         $query .= $query2;
1663                 }
1664                 return $query;
1665         }
1666
1667         /**
1668          * Get a real URL referring to this title, with interwiki link and
1669          * fragment
1670          *
1671          * @see self::getLocalURL for the arguments.
1672          * @see wfExpandUrl
1673          * @param array|string $query
1674          * @param bool $query2
1675          * @param string $proto Protocol type to use in URL
1676          * @return string The URL
1677          */
1678         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1679                 $query = self::fixUrlQueryArgs( $query, $query2 );
1680
1681                 # Hand off all the decisions on urls to getLocalURL
1682                 $url = $this->getLocalURL( $query );
1683
1684                 # Expand the url to make it a full url. Note that getLocalURL has the
1685                 # potential to output full urls for a variety of reasons, so we use
1686                 # wfExpandUrl instead of simply prepending $wgServer
1687                 $url = wfExpandUrl( $url, $proto );
1688
1689                 # Finally, add the fragment.
1690                 $url .= $this->getFragmentForURL();
1691
1692                 Hooks::run( 'GetFullURL', array( &$this, &$url, $query ) );
1693                 return $url;
1694         }
1695
1696         /**
1697          * Get a URL with no fragment or server name (relative URL) from a Title object.
1698          * If this page is generated with action=render, however,
1699          * $wgServer is prepended to make an absolute URL.
1700          *
1701          * @see self::getFullURL to always get an absolute URL.
1702          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1703          *  valid to link, locally, to the current Title.
1704          * @see self::newFromText to produce a Title object.
1705          *
1706          * @param string|array $query An optional query string,
1707          *   not used for interwiki links. Can be specified as an associative array as well,
1708          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1709          *   Some query patterns will trigger various shorturl path replacements.
1710          * @param array $query2 An optional secondary query array. This one MUST
1711          *   be an array. If a string is passed it will be interpreted as a deprecated
1712          *   variant argument and urlencoded into a variant= argument.
1713          *   This second query argument will be added to the $query
1714          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1715          *   pair in the first parameter array instead.
1716          *
1717          * @return string String of the URL.
1718          */
1719         public function getLocalURL( $query = '', $query2 = false ) {
1720                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1721
1722                 $query = self::fixUrlQueryArgs( $query, $query2 );
1723
1724                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1725                 if ( $interwiki ) {
1726                         $namespace = $this->getNsText();
1727                         if ( $namespace != '' ) {
1728                                 # Can this actually happen? Interwikis shouldn't be parsed.
1729                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1730                                 $namespace .= ':';
1731                         }
1732                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1733                         $url = wfAppendQuery( $url, $query );
1734                 } else {
1735                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1736                         if ( $query == '' ) {
1737                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1738                                 Hooks::run( 'GetLocalURL::Article', array( &$this, &$url ) );
1739                         } else {
1740                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1741                                 $url = false;
1742                                 $matches = array();
1743
1744                                 if ( !empty( $wgActionPaths )
1745                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1746                                 ) {
1747                                         $action = urldecode( $matches[2] );
1748                                         if ( isset( $wgActionPaths[$action] ) ) {
1749                                                 $query = $matches[1];
1750                                                 if ( isset( $matches[4] ) ) {
1751                                                         $query .= $matches[4];
1752                                                 }
1753                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1754                                                 if ( $query != '' ) {
1755                                                         $url = wfAppendQuery( $url, $query );
1756                                                 }
1757                                         }
1758                                 }
1759
1760                                 if ( $url === false
1761                                         && $wgVariantArticlePath
1762                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1763                                         && $this->getPageLanguage()->hasVariants()
1764                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1765                                 ) {
1766                                         $variant = urldecode( $matches[1] );
1767                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1768                                                 // Only do the variant replacement if the given variant is a valid
1769                                                 // variant for the page's language.
1770                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1771                                                 $url = str_replace( '$1', $dbkey, $url );
1772                                         }
1773                                 }
1774
1775                                 if ( $url === false ) {
1776                                         if ( $query == '-' ) {
1777                                                 $query = '';
1778                                         }
1779                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1780                                 }
1781                         }
1782
1783                         Hooks::run( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1784
1785                         // @todo FIXME: This causes breakage in various places when we
1786                         // actually expected a local URL and end up with dupe prefixes.
1787                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1788                                 $url = $wgServer . $url;
1789                         }
1790                 }
1791                 Hooks::run( 'GetLocalURL', array( &$this, &$url, $query ) );
1792                 return $url;
1793         }
1794
1795         /**
1796          * Get a URL that's the simplest URL that will be valid to link, locally,
1797          * to the current Title.  It includes the fragment, but does not include
1798          * the server unless action=render is used (or the link is external).  If
1799          * there's a fragment but the prefixed text is empty, we just return a link
1800          * to the fragment.
1801          *
1802          * The result obviously should not be URL-escaped, but does need to be
1803          * HTML-escaped if it's being output in HTML.
1804          *
1805          * @param array $query
1806          * @param bool $query2
1807          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1808          * @see self::getLocalURL for the arguments.
1809          * @return string The URL
1810          */
1811         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1812                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1813                         $ret = $this->getFullURL( $query, $query2, $proto );
1814                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1815                         $ret = $this->getFragmentForURL();
1816                 } else {
1817                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1818                 }
1819                 return $ret;
1820         }
1821
1822         /**
1823          * Get the URL form for an internal link.
1824          * - Used in various Squid-related code, in case we have a different
1825          * internal hostname for the server from the exposed one.
1826          *
1827          * This uses $wgInternalServer to qualify the path, or $wgServer
1828          * if $wgInternalServer is not set. If the server variable used is
1829          * protocol-relative, the URL will be expanded to http://
1830          *
1831          * @see self::getLocalURL for the arguments.
1832          * @return string The URL
1833          */
1834         public function getInternalURL( $query = '', $query2 = false ) {
1835                 global $wgInternalServer, $wgServer;
1836                 $query = self::fixUrlQueryArgs( $query, $query2 );
1837                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1838                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1839                 Hooks::run( 'GetInternalURL', array( &$this, &$url, $query ) );
1840                 return $url;
1841         }
1842
1843         /**
1844          * Get the URL for a canonical link, for use in things like IRC and
1845          * e-mail notifications. Uses $wgCanonicalServer and the
1846          * GetCanonicalURL hook.
1847          *
1848          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1849          *
1850          * @see self::getLocalURL for the arguments.
1851          * @return string The URL
1852          * @since 1.18
1853          */
1854         public function getCanonicalURL( $query = '', $query2 = false ) {
1855                 $query = self::fixUrlQueryArgs( $query, $query2 );
1856                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1857                 Hooks::run( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1858                 return $url;
1859         }
1860
1861         /**
1862          * Get the edit URL for this Title
1863          *
1864          * @return string The URL, or a null string if this is an interwiki link
1865          */
1866         public function getEditURL() {
1867                 if ( $this->isExternal() ) {
1868                         return '';
1869                 }
1870                 $s = $this->getLocalURL( 'action=edit' );
1871
1872                 return $s;
1873         }
1874
1875         /**
1876          * Is $wgUser watching this page?
1877          *
1878          * @deprecated since 1.20; use User::isWatched() instead.
1879          * @return bool
1880          */
1881         public function userIsWatching() {
1882                 global $wgUser;
1883
1884                 if ( is_null( $this->mWatched ) ) {
1885                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1886                                 $this->mWatched = false;
1887                         } else {
1888                                 $this->mWatched = $wgUser->isWatched( $this );
1889                         }
1890                 }
1891                 return $this->mWatched;
1892         }
1893
1894         /**
1895          * Can $user perform $action on this page?
1896          * This skips potentially expensive cascading permission checks
1897          * as well as avoids expensive error formatting
1898          *
1899          * Suitable for use for nonessential UI controls in common cases, but
1900          * _not_ for functional access control.
1901          *
1902          * May provide false positives, but should never provide a false negative.
1903          *
1904          * @param string $action Action that permission needs to be checked for
1905          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1906          * @return bool
1907          */
1908         public function quickUserCan( $action, $user = null ) {
1909                 return $this->userCan( $action, $user, false );
1910         }
1911
1912         /**
1913          * Can $user perform $action on this page?
1914          *
1915          * @param string $action Action that permission needs to be checked for
1916          * @param User $user User to check (since 1.19); $wgUser will be used if not
1917          *   provided.
1918          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1919          * @return bool
1920          */
1921         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1922                 if ( !$user instanceof User ) {
1923                         global $wgUser;
1924                         $user = $wgUser;
1925                 }
1926
1927                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1928         }
1929
1930         /**
1931          * Can $user perform $action on this page?
1932          *
1933          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1934          *
1935          * @param string $action Action that permission needs to be checked for
1936          * @param User $user User to check
1937          * @param string $rigor One of (quick,full,secure)
1938          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
1939          *   - full   : does cheap and expensive checks possibly from a slave
1940          *   - secure : does cheap and expensive checks, using the master as needed
1941          * @param bool $short Set this to true to stop after the first permission error.
1942          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1943          *   whose corresponding errors may be ignored.
1944          * @return array Array of arguments to wfMessage to explain permissions problems.
1945          */
1946         public function getUserPermissionsErrors(
1947                 $action, $user, $rigor = 'secure', $ignoreErrors = array()
1948         ) {
1949                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1950
1951                 // Remove the errors being ignored.
1952                 foreach ( $errors as $index => $error ) {
1953                         $error_key = is_array( $error ) ? $error[0] : $error;
1954
1955                         if ( in_array( $error_key, $ignoreErrors ) ) {
1956                                 unset( $errors[$index] );
1957                         }
1958                 }
1959
1960                 return $errors;
1961         }
1962
1963         /**
1964          * Permissions checks that fail most often, and which are easiest to test.
1965          *
1966          * @param string $action The action to check
1967          * @param User $user User to check
1968          * @param array $errors List of current errors
1969          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1970          * @param bool $short Short circuit on first error
1971          *
1972          * @return array List of errors
1973          */
1974         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1975                 if ( !Hooks::run( 'TitleQuickPermissions',
1976                         array( $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ) )
1977                 ) {
1978                         return $errors;
1979                 }
1980
1981                 if ( $action == 'create' ) {
1982                         if (
1983                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1984                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1985                         ) {
1986                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1987                         }
1988                 } elseif ( $action == 'move' ) {
1989                         if ( !$user->isAllowed( 'move-rootuserpages' )
1990                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1991                                 // Show user page-specific message only if the user can move other pages
1992                                 $errors[] = array( 'cant-move-user-page' );
1993                         }
1994
1995                         // Check if user is allowed to move files if it's a file
1996                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1997                                 $errors[] = array( 'movenotallowedfile' );
1998                         }
1999
2000                         // Check if user is allowed to move category pages if it's a category page
2001                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2002                                 $errors[] = array( 'cant-move-category-page' );
2003                         }
2004
2005                         if ( !$user->isAllowed( 'move' ) ) {
2006                                 // User can't move anything
2007                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2008                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2009                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2010                                         // custom message if logged-in users without any special rights can move
2011                                         $errors[] = array( 'movenologintext' );
2012                                 } else {
2013                                         $errors[] = array( 'movenotallowed' );
2014                                 }
2015                         }
2016                 } elseif ( $action == 'move-target' ) {
2017                         if ( !$user->isAllowed( 'move' ) ) {
2018                                 // User can't move anything
2019                                 $errors[] = array( 'movenotallowed' );
2020                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2021                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2022                                 // Show user page-specific message only if the user can move other pages
2023                                 $errors[] = array( 'cant-move-to-user-page' );
2024                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2025                                         && $this->mNamespace == NS_CATEGORY ) {
2026                                 // Show category page-specific message only if the user can move other pages
2027                                 $errors[] = array( 'cant-move-to-category-page' );
2028                         }
2029                 } elseif ( !$user->isAllowed( $action ) ) {
2030                         $errors[] = $this->missingPermissionError( $action, $short );
2031                 }
2032
2033                 return $errors;
2034         }
2035
2036         /**
2037          * Add the resulting error code to the errors array
2038          *
2039          * @param array $errors List of current errors
2040          * @param array $result Result of errors
2041          *
2042          * @return array List of errors
2043          */
2044         private function resultToError( $errors, $result ) {
2045                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2046                         // A single array representing an error
2047                         $errors[] = $result;
2048                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2049                         // A nested array representing multiple errors
2050                         $errors = array_merge( $errors, $result );
2051                 } elseif ( $result !== '' && is_string( $result ) ) {
2052                         // A string representing a message-id
2053                         $errors[] = array( $result );
2054                 } elseif ( $result === false ) {
2055                         // a generic "We don't want them to do that"
2056                         $errors[] = array( 'badaccess-group0' );
2057                 }
2058                 return $errors;
2059         }
2060
2061         /**
2062          * Check various permission hooks
2063          *
2064          * @param string $action The action to check
2065          * @param User $user User to check
2066          * @param array $errors List of current errors
2067          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2068          * @param bool $short Short circuit on first error
2069          *
2070          * @return array List of errors
2071          */
2072         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2073                 // Use getUserPermissionsErrors instead
2074                 $result = '';
2075                 if ( !Hooks::run( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2076                         return $result ? array() : array( array( 'badaccess-group0' ) );
2077                 }
2078                 // Check getUserPermissionsErrors hook
2079                 if ( !Hooks::run( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2080                         $errors = $this->resultToError( $errors, $result );
2081                 }
2082                 // Check getUserPermissionsErrorsExpensive hook
2083                 if (
2084                         $rigor !== 'quick'
2085                         && !( $short && count( $errors ) > 0 )
2086                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2087                 ) {
2088                         $errors = $this->resultToError( $errors, $result );
2089                 }
2090
2091                 return $errors;
2092         }
2093
2094         /**
2095          * Check permissions on special pages & namespaces
2096          *
2097          * @param string $action The action to check
2098          * @param User $user User to check
2099          * @param array $errors List of current errors
2100          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2101          * @param bool $short Short circuit on first error
2102          *
2103          * @return array List of errors
2104          */
2105         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2106                 # Only 'createaccount' can be performed on special pages,
2107                 # which don't actually exist in the DB.
2108                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2109                         $errors[] = array( 'ns-specialprotected' );
2110                 }
2111
2112                 # Check $wgNamespaceProtection for restricted namespaces
2113                 if ( $this->isNamespaceProtected( $user ) ) {
2114                         $ns = $this->mNamespace == NS_MAIN ?
2115                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2116                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2117                                 array( 'protectedinterface', $action ) : array( 'namespaceprotected', $ns, $action );
2118                 }
2119
2120                 return $errors;
2121         }
2122
2123         /**
2124          * Check CSS/JS sub-page permissions
2125          *
2126          * @param string $action The action to check
2127          * @param User $user User to check
2128          * @param array $errors List of current errors
2129          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2130          * @param bool $short Short circuit on first error
2131          *
2132          * @return array List of errors
2133          */
2134         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2135                 # Protect css/js subpages of user pages
2136                 # XXX: this might be better using restrictions
2137                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2138                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2139                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2140                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2141                                         $errors[] = array( 'mycustomcssprotected', $action );
2142                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2143                                         $errors[] = array( 'mycustomjsprotected', $action );
2144                                 }
2145                         } else {
2146                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2147                                         $errors[] = array( 'customcssprotected', $action );
2148                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2149                                         $errors[] = array( 'customjsprotected', $action );
2150                                 }
2151                         }
2152                 }
2153
2154                 return $errors;
2155         }
2156
2157         /**
2158          * Check against page_restrictions table requirements on this
2159          * page. The user must possess all required rights for this
2160          * action.
2161          *
2162          * @param string $action The action to check
2163          * @param User $user User to check
2164          * @param array $errors List of current errors
2165          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2166          * @param bool $short Short circuit on first error
2167          *
2168          * @return array List of errors
2169          */
2170         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2171                 foreach ( $this->getRestrictions( $action ) as $right ) {
2172                         // Backwards compatibility, rewrite sysop -> editprotected
2173                         if ( $right == 'sysop' ) {
2174                                 $right = 'editprotected';
2175                         }
2176                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2177                         if ( $right == 'autoconfirmed' ) {
2178                                 $right = 'editsemiprotected';
2179                         }
2180                         if ( $right == '' ) {
2181                                 continue;
2182                         }
2183                         if ( !$user->isAllowed( $right ) ) {
2184                                 $errors[] = array( 'protectedpagetext', $right, $action );
2185                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2186                                 $errors[] = array( 'protectedpagetext', 'protect', $action );
2187                         }
2188                 }
2189
2190                 return $errors;
2191         }
2192
2193         /**
2194          * Check restrictions on cascading pages.
2195          *
2196          * @param string $action The action to check
2197          * @param User $user User to check
2198          * @param array $errors List of current errors
2199          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2200          * @param bool $short Short circuit on first error
2201          *
2202          * @return array List of errors
2203          */
2204         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2205                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2206                         # We /could/ use the protection level on the source page, but it's
2207                         # fairly ugly as we have to establish a precedence hierarchy for pages
2208                         # included by multiple cascade-protected pages. So just restrict
2209                         # it to people with 'protect' permission, as they could remove the
2210                         # protection anyway.
2211                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2212                         # Cascading protection depends on more than this page...
2213                         # Several cascading protected pages may include this page...
2214                         # Check each cascading level
2215                         # This is only for protection restrictions, not for all actions
2216                         if ( isset( $restrictions[$action] ) ) {
2217                                 foreach ( $restrictions[$action] as $right ) {
2218                                         // Backwards compatibility, rewrite sysop -> editprotected
2219                                         if ( $right == 'sysop' ) {
2220                                                 $right = 'editprotected';
2221                                         }
2222                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2223                                         if ( $right == 'autoconfirmed' ) {
2224                                                 $right = 'editsemiprotected';
2225                                         }
2226                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2227                                                 $pages = '';
2228                                                 foreach ( $cascadingSources as $page ) {
2229                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2230                                                 }
2231                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages, $action );
2232                                         }
2233                                 }
2234                         }
2235                 }
2236
2237                 return $errors;
2238         }
2239
2240         /**
2241          * Check action permissions not already checked in checkQuickPermissions
2242          *
2243          * @param string $action The action to check
2244          * @param User $user User to check
2245          * @param array $errors List of current errors
2246          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2247          * @param bool $short Short circuit on first error
2248          *
2249          * @return array List of errors
2250          */
2251         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2252                 global $wgDeleteRevisionsLimit, $wgLang;
2253
2254                 if ( $action == 'protect' ) {
2255                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2256                                 // If they can't edit, they shouldn't protect.
2257                                 $errors[] = array( 'protect-cantedit' );
2258                         }
2259                 } elseif ( $action == 'create' ) {
2260                         $title_protection = $this->getTitleProtection();
2261                         if ( $title_protection ) {
2262                                 if ( $title_protection['permission'] == ''
2263                                         || !$user->isAllowed( $title_protection['permission'] )
2264                                 ) {
2265                                         $errors[] = array(
2266                                                 'titleprotected',
2267                                                 User::whoIs( $title_protection['user'] ),
2268                                                 $title_protection['reason']
2269                                         );
2270                                 }
2271                         }
2272                 } elseif ( $action == 'move' ) {
2273                         // Check for immobile pages
2274                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2275                                 // Specific message for this case
2276                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2277                         } elseif ( !$this->isMovable() ) {
2278                                 // Less specific message for rarer cases
2279                                 $errors[] = array( 'immobile-source-page' );
2280                         }
2281                 } elseif ( $action == 'move-target' ) {
2282                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2283                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2284                         } elseif ( !$this->isMovable() ) {
2285                                 $errors[] = array( 'immobile-target-page' );
2286                         }
2287                 } elseif ( $action == 'delete' ) {
2288                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, array(), $rigor, true );
2289                         if ( !$tempErrors ) {
2290                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2291                                         $user, $tempErrors, $rigor, true );
2292                         }
2293                         if ( $tempErrors ) {
2294                                 // If protection keeps them from editing, they shouldn't be able to delete.
2295                                 $errors[] = array( 'deleteprotected' );
2296                         }
2297                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2298                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2299                         ) {
2300                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2301                         }
2302                 }
2303                 return $errors;
2304         }
2305
2306         /**
2307          * Check that the user isn't blocked from editing.
2308          *
2309          * @param string $action The action to check
2310          * @param User $user User to check
2311          * @param array $errors List of current errors
2312          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2313          * @param bool $short Short circuit on first error
2314          *
2315          * @return array List of errors
2316          */
2317         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2318                 // Account creation blocks handled at userlogin.
2319                 // Unblocking handled in SpecialUnblock
2320                 if ( $rigor === 'quick' || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2321                         return $errors;
2322                 }
2323
2324                 global $wgEmailConfirmToEdit;
2325
2326                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2327                         $errors[] = array( 'confirmedittext' );
2328                 }
2329
2330                 $useSlave = ( $rigor !== 'secure' );
2331                 if ( ( $action == 'edit' || $action == 'create' )
2332                         && !$user->isBlockedFrom( $this, $useSlave )
2333                 ) {
2334                         // Don't block the user from editing their own talk page unless they've been
2335                         // explicitly blocked from that too.
2336                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2337                         // @todo FIXME: Pass the relevant context into this function.
2338                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2339                 }
2340
2341                 return $errors;
2342         }
2343
2344         /**
2345          * Check that the user is allowed to read this page.
2346          *
2347          * @param string $action The action to check
2348          * @param User $user User to check
2349          * @param array $errors List of current errors
2350          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2351          * @param bool $short Short circuit on first error
2352          *
2353          * @return array List of errors
2354          */
2355         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2356                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2357
2358                 $whitelisted = false;
2359                 if ( User::isEveryoneAllowed( 'read' ) ) {
2360                         # Shortcut for public wikis, allows skipping quite a bit of code
2361                         $whitelisted = true;
2362                 } elseif ( $user->isAllowed( 'read' ) ) {
2363                         # If the user is allowed to read pages, he is allowed to read all pages
2364                         $whitelisted = true;
2365                 } elseif ( $this->isSpecial( 'Userlogin' )
2366                         || $this->isSpecial( 'ChangePassword' )
2367                         || $this->isSpecial( 'PasswordReset' )
2368                 ) {
2369                         # Always grant access to the login page.
2370                         # Even anons need to be able to log in.
2371                         $whitelisted = true;
2372                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2373                         # Time to check the whitelist
2374                         # Only do these checks is there's something to check against
2375                         $name = $this->getPrefixedText();
2376                         $dbName = $this->getPrefixedDBkey();
2377
2378                         // Check for explicit whitelisting with and without underscores
2379                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2380                                 $whitelisted = true;
2381                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2382                                 # Old settings might have the title prefixed with
2383                                 # a colon for main-namespace pages
2384                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2385                                         $whitelisted = true;
2386                                 }
2387                         } elseif ( $this->isSpecialPage() ) {
2388                                 # If it's a special page, ditch the subpage bit and check again
2389                                 $name = $this->getDBkey();
2390                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2391                                 if ( $name ) {
2392                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2393                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2394                                                 $whitelisted = true;
2395                                         }
2396                                 }
2397                         }
2398                 }
2399
2400                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2401                         $name = $this->getPrefixedText();
2402                         // Check for regex whitelisting
2403                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2404                                 if ( preg_match( $listItem, $name ) ) {
2405                                         $whitelisted = true;
2406                                         break;
2407                                 }
2408                         }
2409                 }
2410
2411                 if ( !$whitelisted ) {
2412                         # If the title is not whitelisted, give extensions a chance to do so...
2413                         Hooks::run( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2414                         if ( !$whitelisted ) {
2415                                 $errors[] = $this->missingPermissionError( $action, $short );
2416                         }
2417                 }
2418
2419                 return $errors;
2420         }
2421
2422         /**
2423          * Get a description array when the user doesn't have the right to perform
2424          * $action (i.e. when User::isAllowed() returns false)
2425          *
2426          * @param string $action The action to check
2427          * @param bool $short Short circuit on first error
2428          * @return array List of errors
2429          */
2430         private function missingPermissionError( $action, $short ) {
2431                 // We avoid expensive display logic for quickUserCan's and such
2432                 if ( $short ) {
2433                         return array( 'badaccess-group0' );
2434                 }
2435
2436                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2437                         User::getGroupsWithPermission( $action ) );
2438
2439                 if ( count( $groups ) ) {
2440                         global $wgLang;
2441                         return array(
2442                                 'badaccess-groups',
2443                                 $wgLang->commaList( $groups ),
2444                                 count( $groups )
2445                         );
2446                 } else {
2447                         return array( 'badaccess-group0' );
2448                 }
2449         }
2450
2451         /**
2452          * Can $user perform $action on this page? This is an internal function,
2453          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2454          * checks on wfReadOnly() and blocks)
2455          *
2456          * @param string $action Action that permission needs to be checked for
2457          * @param User $user User to check
2458          * @param string $rigor One of (quick,full,secure)
2459          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
2460          *   - full   : does cheap and expensive checks possibly from a slave
2461          *   - secure : does cheap and expensive checks, using the master as needed
2462          * @param bool $short Set this to true to stop after the first permission error.
2463          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2464          */
2465         protected function getUserPermissionsErrorsInternal(
2466                 $action, $user, $rigor = 'secure', $short = false
2467         ) {
2468                 if ( $rigor === true ) {
2469                         $rigor = 'secure'; // b/c
2470                 } elseif ( $rigor === false ) {
2471                         $rigor = 'quick'; // b/c
2472                 } elseif ( !in_array( $rigor, array( 'quick', 'full', 'secure' ) ) ) {
2473                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2474                 }
2475
2476                 # Read has special handling
2477                 if ( $action == 'read' ) {
2478                         $checks = array(
2479                                 'checkPermissionHooks',
2480                                 'checkReadPermissions',
2481                         );
2482                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2483                 # here as it will lead to duplicate error messages. This is okay to do
2484                 # since anywhere that checks for create will also check for edit, and
2485                 # those checks are called for edit.
2486                 } elseif ( $action == 'create' ) {
2487                         $checks = array(
2488                                 'checkQuickPermissions',
2489                                 'checkPermissionHooks',
2490                                 'checkPageRestrictions',
2491                                 'checkCascadingSourcesRestrictions',
2492                                 'checkActionPermissions',
2493                                 'checkUserBlock'
2494                         );
2495                 } else {
2496                         $checks = array(
2497                                 'checkQuickPermissions',
2498                                 'checkPermissionHooks',
2499                                 'checkSpecialsAndNSPermissions',
2500                                 'checkCSSandJSPermissions',
2501                                 'checkPageRestrictions',
2502                                 'checkCascadingSourcesRestrictions',
2503                                 'checkActionPermissions',
2504                                 'checkUserBlock'
2505                         );
2506                 }
2507
2508                 $errors = array();
2509                 while ( count( $checks ) > 0 &&
2510                                 !( $short && count( $errors ) > 0 ) ) {
2511                         $method = array_shift( $checks );
2512                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2513                 }
2514
2515                 return $errors;
2516         }
2517
2518         /**
2519          * Get a filtered list of all restriction types supported by this wiki.
2520          * @param bool $exists True to get all restriction types that apply to
2521          * titles that do exist, False for all restriction types that apply to
2522          * titles that do not exist
2523          * @return array
2524          */
2525         public static function getFilteredRestrictionTypes( $exists = true ) {
2526                 global $wgRestrictionTypes;
2527                 $types = $wgRestrictionTypes;
2528                 if ( $exists ) {
2529                         # Remove the create restriction for existing titles
2530                         $types = array_diff( $types, array( 'create' ) );
2531                 } else {
2532                         # Only the create and upload restrictions apply to non-existing titles
2533                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2534                 }
2535                 return $types;
2536         }
2537
2538         /**
2539          * Returns restriction types for the current Title
2540          *
2541          * @return array Applicable restriction types
2542          */
2543         public function getRestrictionTypes() {
2544                 if ( $this->isSpecialPage() ) {
2545                         return array();
2546                 }
2547
2548                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2549
2550                 if ( $this->getNamespace() != NS_FILE ) {
2551                         # Remove the upload restriction for non-file titles
2552                         $types = array_diff( $types, array( 'upload' ) );
2553                 }
2554
2555                 Hooks::run( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2556
2557                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2558                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2559
2560                 return $types;
2561         }
2562
2563         /**
2564          * Is this title subject to title protection?
2565          * Title protection is the one applied against creation of such title.
2566          *
2567          * @return array|bool An associative array representing any existent title
2568          *   protection, or false if there's none.
2569          */
2570         public function getTitleProtection() {
2571                 // Can't protect pages in special namespaces
2572                 if ( $this->getNamespace() < 0 ) {
2573                         return false;
2574                 }
2575
2576                 // Can't protect pages that exist.
2577                 if ( $this->exists() ) {
2578                         return false;
2579                 }
2580
2581                 if ( $this->mTitleProtection === null ) {
2582                         $dbr = wfGetDB( DB_SLAVE );
2583                         $res = $dbr->select(
2584                                 'protected_titles',
2585                                 array(
2586                                         'user' => 'pt_user',
2587                                         'reason' => 'pt_reason',
2588                                         'expiry' => 'pt_expiry',
2589                                         'permission' => 'pt_create_perm'
2590                                 ),
2591                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2592                                 __METHOD__
2593                         );
2594
2595                         // fetchRow returns false if there are no rows.
2596                         $row = $dbr->fetchRow( $res );
2597                         if ( $row ) {
2598                                 if ( $row['permission'] == 'sysop' ) {
2599                                         $row['permission'] = 'editprotected'; // B/C
2600                                 }
2601                                 if ( $row['permission'] == 'autoconfirmed' ) {
2602                                         $row['permission'] = 'editsemiprotected'; // B/C
2603                                 }
2604                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2605                         }
2606                         $this->mTitleProtection = $row;
2607                 }
2608                 return $this->mTitleProtection;
2609         }
2610
2611         /**
2612          * Remove any title protection due to page existing
2613          */
2614         public function deleteTitleProtection() {
2615                 $dbw = wfGetDB( DB_MASTER );
2616
2617                 $dbw->delete(
2618                         'protected_titles',
2619                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2620                         __METHOD__
2621                 );
2622                 $this->mTitleProtection = false;
2623         }
2624
2625         /**
2626          * Is this page "semi-protected" - the *only* protection levels are listed
2627          * in $wgSemiprotectedRestrictionLevels?
2628          *
2629          * @param string $action Action to check (default: edit)
2630          * @return bool
2631          */
2632         public function isSemiProtected( $action = 'edit' ) {
2633                 global $wgSemiprotectedRestrictionLevels;
2634
2635                 $restrictions = $this->getRestrictions( $action );
2636                 $semi = $wgSemiprotectedRestrictionLevels;
2637                 if ( !$restrictions || !$semi ) {
2638                         // Not protected, or all protection is full protection
2639                         return false;
2640                 }
2641
2642                 // Remap autoconfirmed to editsemiprotected for BC
2643                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2644                         $semi[$key] = 'editsemiprotected';
2645                 }
2646                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2647                         $restrictions[$key] = 'editsemiprotected';
2648                 }
2649
2650                 return !array_diff( $restrictions, $semi );
2651         }
2652
2653         /**
2654          * Does the title correspond to a protected article?
2655          *
2656          * @param string $action The action the page is protected from,
2657          * by default checks all actions.
2658          * @return bool
2659          */
2660         public function isProtected( $action = '' ) {
2661                 global $wgRestrictionLevels;
2662
2663                 $restrictionTypes = $this->getRestrictionTypes();
2664
2665                 # Special pages have inherent protection
2666                 if ( $this->isSpecialPage() ) {
2667                         return true;
2668                 }
2669
2670                 # Check regular protection levels
2671                 foreach ( $restrictionTypes as $type ) {
2672                         if ( $action == $type || $action == '' ) {
2673                                 $r = $this->getRestrictions( $type );
2674                                 foreach ( $wgRestrictionLevels as $level ) {
2675                                         if ( in_array( $level, $r ) && $level != '' ) {
2676                                                 return true;
2677                                         }
2678                                 }
2679                         }
2680                 }
2681
2682                 return false;
2683         }
2684
2685         /**
2686          * Determines if $user is unable to edit this page because it has been protected
2687          * by $wgNamespaceProtection.
2688          *
2689          * @param User $user User object to check permissions
2690          * @return bool
2691          */
2692         public function isNamespaceProtected( User $user ) {
2693                 global $wgNamespaceProtection;
2694
2695                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2696                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2697                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2698                                         return true;
2699                                 }
2700                         }
2701                 }
2702                 return false;
2703         }
2704
2705         /**
2706          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2707          *
2708          * @return bool If the page is subject to cascading restrictions.
2709          */
2710         public function isCascadeProtected() {
2711                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2712                 return ( $sources > 0 );
2713         }
2714
2715         /**
2716          * Determines whether cascading protection sources have already been loaded from
2717          * the database.
2718          *
2719          * @param bool $getPages True to check if the pages are loaded, or false to check
2720          * if the status is loaded.
2721          * @return bool Whether or not the specified information has been loaded
2722          * @since 1.23
2723          */
2724         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2725                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2726         }
2727
2728         /**
2729          * Cascading protection: Get the source of any cascading restrictions on this page.
2730          *
2731          * @param bool $getPages Whether or not to retrieve the actual pages
2732          *        that the restrictions have come from and the actual restrictions
2733          *        themselves.
2734          * @return array Two elements: First is an array of Title objects of the
2735          *        pages from which cascading restrictions have come, false for
2736          *        none, or true if such restrictions exist but $getPages was not
2737          *        set. Second is an array like that returned by
2738          *        Title::getAllRestrictions(), or an empty array if $getPages is
2739          *        false.
2740          */
2741         public function getCascadeProtectionSources( $getPages = true ) {
2742                 $pagerestrictions = array();
2743
2744                 if ( $this->mCascadeSources !== null && $getPages ) {
2745                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2746                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2747                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2748                 }
2749
2750                 $dbr = wfGetDB( DB_SLAVE );
2751
2752                 if ( $this->getNamespace() == NS_FILE ) {
2753                         $tables = array( 'imagelinks', 'page_restrictions' );
2754                         $where_clauses = array(
2755                                 'il_to' => $this->getDBkey(),
2756                                 'il_from=pr_page',
2757                                 'pr_cascade' => 1
2758                         );
2759                 } else {
2760                         $tables = array( 'templatelinks', 'page_restrictions' );
2761                         $where_clauses = array(
2762                                 'tl_namespace' => $this->getNamespace(),
2763                                 'tl_title' => $this->getDBkey(),
2764                                 'tl_from=pr_page',
2765                                 'pr_cascade' => 1
2766                         );
2767                 }
2768
2769                 if ( $getPages ) {
2770                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2771                                 'pr_expiry', 'pr_type', 'pr_level' );
2772                         $where_clauses[] = 'page_id=pr_page';
2773                         $tables[] = 'page';
2774                 } else {
2775                         $cols = array( 'pr_expiry' );
2776                 }
2777
2778                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2779
2780                 $sources = $getPages ? array() : false;
2781                 $now = wfTimestampNow();
2782
2783                 foreach ( $res as $row ) {
2784                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2785                         if ( $expiry > $now ) {
2786                                 if ( $getPages ) {
2787                                         $page_id = $row->pr_page;
2788                                         $page_ns = $row->page_namespace;
2789                                         $page_title = $row->page_title;
2790                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2791                                         # Add groups needed for each restriction type if its not already there
2792                                         # Make sure this restriction type still exists
2793
2794                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2795                                                 $pagerestrictions[$row->pr_type] = array();
2796                                         }
2797
2798                                         if (
2799                                                 isset( $pagerestrictions[$row->pr_type] )
2800                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2801                                         ) {
2802                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2803                                         }
2804                                 } else {
2805                                         $sources = true;
2806                                 }
2807                         }
2808                 }
2809
2810                 if ( $getPages ) {
2811                         $this->mCascadeSources = $sources;
2812                         $this->mCascadingRestrictions = $pagerestrictions;
2813                 } else {
2814                         $this->mHasCascadingRestrictions = $sources;
2815                 }
2816
2817                 return array( $sources, $pagerestrictions );
2818         }
2819
2820         /**
2821          * Accessor for mRestrictionsLoaded
2822          *
2823          * @return bool Whether or not the page's restrictions have already been
2824          * loaded from the database
2825          * @since 1.23
2826          */
2827         public function areRestrictionsLoaded() {
2828                 return $this->mRestrictionsLoaded;
2829         }
2830
2831         /**
2832          * Accessor/initialisation for mRestrictions
2833          *
2834          * @param string $action Action that permission needs to be checked for
2835          * @return array Restriction levels needed to take the action. All levels are
2836          *     required. Note that restriction levels are normally user rights, but 'sysop'
2837          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2838          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2839          */
2840         public function getRestrictions( $action ) {
2841                 if ( !$this->mRestrictionsLoaded ) {
2842                         $this->loadRestrictions();
2843                 }
2844                 return isset( $this->mRestrictions[$action] )
2845                                 ? $this->mRestrictions[$action]
2846                                 : array();
2847         }
2848
2849         /**
2850          * Accessor/initialisation for mRestrictions
2851          *
2852          * @return array Keys are actions, values are arrays as returned by
2853          *     Title::getRestrictions()
2854          * @since 1.23
2855          */
2856         public function getAllRestrictions() {
2857                 if ( !$this->mRestrictionsLoaded ) {
2858                         $this->loadRestrictions();
2859                 }
2860                 return $this->mRestrictions;
2861         }
2862
2863         /**
2864          * Get the expiry time for the restriction against a given action
2865          *
2866          * @param string $action
2867          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2868          *     or not protected at all, or false if the action is not recognised.
2869          */
2870         public function getRestrictionExpiry( $action ) {
2871                 if ( !$this->mRestrictionsLoaded ) {
2872                         $this->loadRestrictions();
2873                 }
2874                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2875         }
2876
2877         /**
2878          * Returns cascading restrictions for the current article
2879          *
2880          * @return bool
2881          */
2882         function areRestrictionsCascading() {
2883                 if ( !$this->mRestrictionsLoaded ) {
2884                         $this->loadRestrictions();
2885                 }
2886
2887                 return $this->mCascadeRestriction;
2888         }
2889
2890         /**
2891          * Loads a string into mRestrictions array
2892          *
2893          * @param ResultWrapper $res Resource restrictions as an SQL result.
2894          * @param string $oldFashionedRestrictions Comma-separated list of page
2895          *        restrictions from page table (pre 1.10)
2896          */
2897         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2898                 $rows = array();
2899
2900                 foreach ( $res as $row ) {
2901                         $rows[] = $row;
2902                 }
2903
2904                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2905         }
2906
2907         /**
2908          * Compiles list of active page restrictions from both page table (pre 1.10)
2909          * and page_restrictions table for this existing page.
2910          * Public for usage by LiquidThreads.
2911          *
2912          * @param array $rows Array of db result objects
2913          * @param string $oldFashionedRestrictions Comma-separated list of page
2914          *   restrictions from page table (pre 1.10)
2915          */
2916         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2917                 $dbr = wfGetDB( DB_SLAVE );
2918
2919                 $restrictionTypes = $this->getRestrictionTypes();
2920
2921                 foreach ( $restrictionTypes as $type ) {
2922                         $this->mRestrictions[$type] = array();
2923                         $this->mRestrictionsExpiry[$type] = 'infinity';
2924                 }
2925
2926                 $this->mCascadeRestriction = false;
2927
2928                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2929                 if ( $oldFashionedRestrictions !== null ) {
2930                         $this->mOldRestrictions = $oldFashionedRestrictions;
2931                 }
2932
2933                 if ( $this->mOldRestrictions === false ) {
2934                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2935                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2936                 }
2937
2938                 if ( $this->mOldRestrictions != '' ) {
2939                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2940                                 $temp = explode( '=', trim( $restrict ) );
2941                                 if ( count( $temp ) == 1 ) {
2942                                         // old old format should be treated as edit/move restriction
2943                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2944                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2945                                 } else {
2946                                         $restriction = trim( $temp[1] );
2947                                         if ( $restriction != '' ) { //some old entries are empty
2948                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2949                                         }
2950                                 }
2951                         }
2952                 }
2953
2954                 if ( count( $rows ) ) {
2955                         # Current system - load second to make them override.
2956                         $now = wfTimestampNow();
2957
2958                         # Cycle through all the restrictions.
2959                         foreach ( $rows as $row ) {
2960
2961                                 // Don't take care of restrictions types that aren't allowed
2962                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2963                                         continue;
2964                                 }
2965
2966                                 // This code should be refactored, now that it's being used more generally,
2967                                 // But I don't really see any harm in leaving it in Block for now -werdna
2968                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2969
2970                                 // Only apply the restrictions if they haven't expired!
2971                                 if ( !$expiry || $expiry > $now ) {
2972                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2973                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2974
2975                                         $this->mCascadeRestriction |= $row->pr_cascade;
2976                                 }
2977                         }
2978                 }
2979
2980                 $this->mRestrictionsLoaded = true;
2981         }
2982
2983         /**
2984          * Load restrictions from the page_restrictions table
2985          *
2986          * @param string $oldFashionedRestrictions Comma-separated list of page
2987          *   restrictions from page table (pre 1.10)
2988          */
2989         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2990                 if ( !$this->mRestrictionsLoaded ) {
2991                         $dbr = wfGetDB( DB_SLAVE );
2992                         if ( $this->exists() ) {
2993                                 $res = $dbr->select(
2994                                         'page_restrictions',
2995                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2996                                         array( 'pr_page' => $this->getArticleID() ),
2997                                         __METHOD__
2998                                 );
2999
3000                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
3001                         } else {
3002                                 $title_protection = $this->getTitleProtection();
3003
3004                                 if ( $title_protection ) {
3005                                         $now = wfTimestampNow();
3006                                         $expiry = $dbr->decodeExpiry( $title_protection['expiry'] );
3007
3008                                         if ( !$expiry || $expiry > $now ) {
3009                                                 // Apply the restrictions
3010                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3011                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
3012                                         } else { // Get rid of the old restrictions
3013                                                 $this->mTitleProtection = false;
3014                                         }
3015                                 } else {
3016                                         $this->mRestrictionsExpiry['create'] = 'infinity';
3017                                 }
3018                                 $this->mRestrictionsLoaded = true;
3019                         }
3020                 }
3021         }
3022
3023         /**
3024          * Flush the protection cache in this object and force reload from the database.
3025          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3026          */
3027         public function flushRestrictions() {
3028                 $this->mRestrictionsLoaded = false;
3029                 $this->mTitleProtection = null;
3030         }
3031
3032         /**
3033          * Purge expired restrictions from the page_restrictions table
3034          */
3035         static function purgeExpiredRestrictions() {
3036                 if ( wfReadOnly() ) {
3037                         return;
3038                 }
3039
3040                 $method = __METHOD__;
3041                 $dbw = wfGetDB( DB_MASTER );
3042                 $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
3043                         $dbw->delete(
3044                                 'page_restrictions',
3045                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3046                                 $method
3047                         );
3048                         $dbw->delete(
3049                                 'protected_titles',
3050                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3051                                 $method
3052                         );
3053                 } );
3054         }
3055
3056         /**
3057          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3058          *
3059          * @return bool
3060          */
3061         public function hasSubpages() {
3062                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3063                         # Duh
3064                         return false;
3065                 }
3066
3067                 # We dynamically add a member variable for the purpose of this method
3068                 # alone to cache the result.  There's no point in having it hanging
3069                 # around uninitialized in every Title object; therefore we only add it
3070                 # if needed and don't declare it statically.
3071                 if ( $this->mHasSubpages === null ) {
3072                         $this->mHasSubpages = false;
3073                         $subpages = $this->getSubpages( 1 );
3074                         if ( $subpages instanceof TitleArray ) {
3075                                 $this->mHasSubpages = (bool)$subpages->count();
3076                         }
3077                 }
3078
3079                 return $this->mHasSubpages;
3080         }
3081
3082         /**
3083          * Get all subpages of this page.
3084          *
3085          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3086          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3087          *  doesn't allow subpages
3088          */
3089         public function getSubpages( $limit = -1 ) {
3090                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3091                         return array();
3092                 }
3093
3094                 $dbr = wfGetDB( DB_SLAVE );
3095                 $conds['page_namespace'] = $this->getNamespace();
3096                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3097                 $options = array();
3098                 if ( $limit > -1 ) {
3099                         $options['LIMIT'] = $limit;
3100                 }
3101                 $this->mSubpages = TitleArray::newFromResult(
3102                         $dbr->select( 'page',
3103                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3104                                 $conds,
3105                                 __METHOD__,
3106                                 $options
3107                         )
3108                 );
3109                 return $this->mSubpages;
3110         }
3111
3112         /**
3113          * Is there a version of this page in the deletion archive?
3114          *
3115          * @return int The number of archived revisions
3116          */
3117         public function isDeleted() {
3118                 if ( $this->getNamespace() < 0 ) {
3119                         $n = 0;
3120                 } else {
3121                         $dbr = wfGetDB( DB_SLAVE );
3122
3123                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3124                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3125                                 __METHOD__
3126                         );
3127                         if ( $this->getNamespace() == NS_FILE ) {
3128                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3129                                         array( 'fa_name' => $this->getDBkey() ),
3130                                         __METHOD__
3131                                 );
3132                         }
3133                 }
3134                 return (int)$n;
3135         }
3136
3137         /**
3138          * Is there a version of this page in the deletion archive?
3139          *
3140          * @return bool
3141          */
3142         public function isDeletedQuick() {
3143                 if ( $this->getNamespace() < 0 ) {
3144                         return false;
3145                 }
3146                 $dbr = wfGetDB( DB_SLAVE );
3147                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3148                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3149                         __METHOD__
3150                 );
3151                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3152                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3153                                 array( 'fa_name' => $this->getDBkey() ),
3154                                 __METHOD__
3155                         );
3156                 }
3157                 return $deleted;
3158         }
3159
3160         /**
3161          * Get the article ID for this Title from the link cache,
3162          * adding it if necessary
3163          *
3164          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3165          *  for update
3166          * @return int The ID
3167          */
3168         public function getArticleID( $flags = 0 ) {
3169                 if ( $this->getNamespace() < 0 ) {
3170                         $this->mArticleID = 0;
3171                         return $this->mArticleID;
3172                 }
3173                 $linkCache = LinkCache::singleton();
3174                 if ( $flags & self::GAID_FOR_UPDATE ) {
3175                         $oldUpdate = $linkCache->forUpdate( true );
3176                         $linkCache->clearLink( $this );
3177                         $this->mArticleID = $linkCache->addLinkObj( $this );
3178                         $linkCache->forUpdate( $oldUpdate );
3179                 } else {
3180                         if ( -1 == $this->mArticleID ) {
3181                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3182                         }
3183                 }
3184                 return $this->mArticleID;
3185         }
3186
3187         /**
3188          * Is this an article that is a redirect page?
3189          * Uses link cache, adding it if necessary
3190          *
3191          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3192          * @return bool
3193          */
3194         public function isRedirect( $flags = 0 ) {
3195                 if ( !is_null( $this->mRedirect ) ) {
3196                         return $this->mRedirect;
3197                 }
3198                 if ( !$this->getArticleID( $flags ) ) {
3199                         $this->mRedirect = false;
3200                         return $this->mRedirect;
3201                 }
3202
3203                 $linkCache = LinkCache::singleton();
3204                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3205                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3206                 if ( $cached === null ) {
3207                         # Trust LinkCache's state over our own
3208                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3209                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3210                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3211                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3212                         # LinkCache to refresh its data from the master.
3213                         $this->mRedirect = false;
3214                         return $this->mRedirect;
3215                 }
3216
3217                 $this->mRedirect = (bool)$cached;
3218
3219                 return $this->mRedirect;
3220         }
3221
3222         /**
3223          * What is the length of this page?
3224          * Uses link cache, adding it if necessary
3225          *
3226          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3227          * @return int
3228          */
3229         public function getLength( $flags = 0 ) {
3230                 if ( $this->mLength != -1 ) {
3231                         return $this->mLength;
3232                 }
3233                 if ( !$this->getArticleID( $flags ) ) {
3234                         $this->mLength = 0;
3235                         return $this->mLength;
3236                 }
3237                 $linkCache = LinkCache::singleton();
3238                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3239                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3240                 if ( $cached === null ) {
3241                         # Trust LinkCache's state over our own, as for isRedirect()
3242                         $this->mLength = 0;
3243                         return $this->mLength;
3244                 }
3245
3246                 $this->mLength = intval( $cached );
3247
3248                 return $this->mLength;
3249         }
3250
3251         /**
3252          * What is the page_latest field for this page?
3253          *
3254          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3255          * @return int Int or 0 if the page doesn't exist
3256          */
3257         public function getLatestRevID( $flags = 0 ) {
3258                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3259                         return intval( $this->mLatestID );
3260                 }
3261                 if ( !$this->getArticleID( $flags ) ) {
3262                         $this->mLatestID = 0;
3263                         return $this->mLatestID;
3264                 }
3265                 $linkCache = LinkCache::singleton();
3266                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3267                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3268                 if ( $cached === null ) {
3269                         # Trust LinkCache's state over our own, as for isRedirect()
3270                         $this->mLatestID = 0;
3271                         return $this->mLatestID;
3272                 }
3273
3274                 $this->mLatestID = intval( $cached );
3275
3276                 return $this->mLatestID;
3277         }
3278
3279         /**
3280          * This clears some fields in this object, and clears any associated
3281          * keys in the "bad links" section of the link cache.
3282          *
3283          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3284          * loading of the new page_id. It's also called from
3285          * WikiPage::doDeleteArticleReal()
3286          *
3287          * @param int $newid The new Article ID
3288          */
3289         public function resetArticleID( $newid ) {
3290                 $linkCache = LinkCache::singleton();
3291                 $linkCache->clearLink( $this );
3292
3293                 if ( $newid === false ) {
3294                         $this->mArticleID = -1;
3295                 } else {
3296                         $this->mArticleID = intval( $newid );
3297                 }
3298                 $this->mRestrictionsLoaded = false;
3299                 $this->mRestrictions = array();
3300                 $this->mOldRestrictions = false;
3301                 $this->mRedirect = null;
3302                 $this->mLength = -1;
3303                 $this->mLatestID = false;
3304                 $this->mContentModel = false;
3305                 $this->mEstimateRevisions = null;
3306                 $this->mPageLanguage = false;
3307                 $this->mDbPageLanguage = null;
3308                 $this->mIsBigDeletion = null;
3309         }
3310
3311         /**
3312          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3313          *
3314          * @param string $text Containing title to capitalize
3315          * @param int $ns Namespace index, defaults to NS_MAIN
3316          * @return string Containing capitalized title
3317          */
3318         public static function capitalize( $text, $ns = NS_MAIN ) {
3319                 global $wgContLang;
3320
3321                 if ( MWNamespace::isCapitalized( $ns ) ) {
3322                         return $wgContLang->ucfirst( $text );
3323                 } else {
3324                         return $text;
3325                 }
3326         }
3327
3328         /**
3329          * Secure and split - main initialisation function for this object
3330          *
3331          * Assumes that mDbkeyform has been set, and is urldecoded
3332          * and uses underscores, but not otherwise munged.  This function
3333          * removes illegal characters, splits off the interwiki and
3334          * namespace prefixes, sets the other forms, and canonicalizes
3335          * everything.
3336          *
3337          * @throws MalformedTitleException On invalid titles
3338          * @return bool True on success
3339          */
3340         private function secureAndSplit() {
3341                 # Initialisation
3342                 $this->mInterwiki = '';
3343                 $this->mFragment = '';
3344                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3345
3346                 $dbkey = $this->mDbkeyform;
3347
3348                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3349                 //        the parsing code with Title, while avoiding massive refactoring.
3350                 // @todo: get rid of secureAndSplit, refactor parsing code.
3351                 $titleParser = self::getTitleParser();
3352                 // MalformedTitleException can be thrown here
3353                 $parts = $titleParser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3354
3355                 # Fill fields
3356                 $this->setFragment( '#' . $parts['fragment'] );
3357                 $this->mInterwiki = $parts['interwiki'];
3358                 $this->mLocalInterwiki = $parts['local_interwiki'];
3359                 $this->mNamespace = $parts['namespace'];
3360                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3361
3362                 $this->mDbkeyform = $parts['dbkey'];
3363                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3364                 $this->mTextform = str_replace( '_', ' ', $this->mDbkeyform );
3365
3366                 # We already know that some pages won't be in the database!
3367                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3368                         $this->mArticleID = 0;
3369                 }
3370
3371                 return true;
3372         }
3373
3374         /**
3375          * Get an array of Title objects linking to this Title
3376          * Also stores the IDs in the link cache.
3377          *
3378          * WARNING: do not use this function on arbitrary user-supplied titles!
3379          * On heavily-used templates it will max out the memory.
3380          *
3381          * @param array $options May be FOR UPDATE
3382          * @param string $table Table name
3383          * @param string $prefix Fields prefix
3384          * @return Title[] Array of Title objects linking here
3385          */
3386         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3387                 if ( count( $options ) > 0 ) {
3388                         $db = wfGetDB( DB_MASTER );
3389                 } else {
3390                         $db = wfGetDB( DB_SLAVE );
3391                 }
3392
3393                 $res = $db->select(
3394                         array( 'page', $table ),
3395                         self::getSelectFields(),
3396                         array(
3397                                 "{$prefix}_from=page_id",
3398                                 "{$prefix}_namespace" => $this->getNamespace(),
3399                                 "{$prefix}_title" => $this->getDBkey() ),
3400                         __METHOD__,
3401                         $options
3402                 );
3403
3404                 $retVal = array();
3405                 if ( $res->numRows() ) {
3406                         $linkCache = LinkCache::singleton();
3407                         foreach ( $res as $row ) {
3408                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3409                                 if ( $titleObj ) {
3410                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3411                                         $retVal[] = $titleObj;
3412                                 }
3413                         }
3414                 }
3415                 return $retVal;
3416         }
3417
3418         /**
3419          * Get an array of Title objects using this Title as a template
3420          * Also stores the IDs in the link cache.
3421          *
3422          * WARNING: do not use this function on arbitrary user-supplied titles!
3423          * On heavily-used templates it will max out the memory.
3424          *
3425          * @param array $options May be FOR UPDATE
3426          * @return Title[] Array of Title the Title objects linking here
3427          */
3428         public function getTemplateLinksTo( $options = array() ) {
3429                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3430         }
3431
3432         /**
3433          * Get an array of Title objects linked from this Title
3434          * Also stores the IDs in the link cache.
3435          *
3436          * WARNING: do not use this function on arbitrary user-supplied titles!
3437          * On heavily-used templates it will max out the memory.
3438          *
3439          * @param array $options May be FOR UPDATE
3440          * @param string $table Table name
3441          * @param string $prefix Fields prefix
3442          * @return array Array of Title objects linking here
3443          */
3444         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3445                 $id = $this->getArticleID();
3446
3447                 # If the page doesn't exist; there can't be any link from this page
3448                 if ( !$id ) {
3449                         return array();
3450                 }
3451
3452                 if ( count( $options ) > 0 ) {
3453                         $db = wfGetDB( DB_MASTER );
3454                 } else {
3455                         $db = wfGetDB( DB_SLAVE );
3456                 }
3457
3458                 $blNamespace = "{$prefix}_namespace";
3459                 $blTitle = "{$prefix}_title";
3460
3461                 $res = $db->select(
3462                         array( $table, 'page' ),
3463                         array_merge(
3464                                 array( $blNamespace, $blTitle ),
3465                                 WikiPage::selectFields()
3466                         ),
3467                         array( "{$prefix}_from" => $id ),
3468                         __METHOD__,
3469                         $options,
3470                         array( 'page' => array(
3471                                 'LEFT JOIN',
3472                                 array( "page_namespace=$blNamespace", "page_title=$blTitle" )
3473                         ) )
3474                 );
3475
3476                 $retVal = array();
3477                 $linkCache = LinkCache::singleton();
3478                 foreach ( $res as $row ) {
3479                         if ( $row->page_id ) {
3480                                 $titleObj = Title::newFromRow( $row );
3481                         } else {
3482                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3483                                 $linkCache->addBadLinkObj( $titleObj );
3484                         }
3485                         $retVal[] = $titleObj;
3486                 }
3487
3488                 return $retVal;
3489         }
3490
3491         /**
3492          * Get an array of Title objects used on this Title as a template
3493          * Also stores the IDs in the link cache.
3494          *
3495          * WARNING: do not use this function on arbitrary user-supplied titles!
3496          * On heavily-used templates it will max out the memory.
3497          *
3498          * @param array $options May be FOR UPDATE
3499          * @return Title[] Array of Title the Title objects used here
3500          */
3501         public function getTemplateLinksFrom( $options = array() ) {
3502                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3503         }
3504
3505         /**
3506          * Get an array of Title objects referring to non-existent articles linked
3507          * from this page.
3508          *
3509          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3510          *   should use redirect table in this case).
3511          * @return Title[] Array of Title the Title objects
3512          */
3513         public function getBrokenLinksFrom() {
3514                 if ( $this->getArticleID() == 0 ) {
3515                         # All links from article ID 0 are false positives
3516                         return array();
3517                 }
3518
3519                 $dbr = wfGetDB( DB_SLAVE );
3520                 $res = $dbr->select(
3521                         array( 'page', 'pagelinks' ),
3522                         array( 'pl_namespace', 'pl_title' ),
3523                         array(
3524                                 'pl_from' => $this->getArticleID(),
3525                                 'page_namespace IS NULL'
3526                         ),
3527                         __METHOD__, array(),
3528                         array(
3529                                 'page' => array(
3530                                         'LEFT JOIN',
3531                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3532                                 )
3533                         )
3534                 );
3535
3536                 $retVal = array();
3537                 foreach ( $res as $row ) {
3538                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3539                 }
3540                 return $retVal;
3541         }
3542
3543         /**
3544          * Get a list of URLs to purge from the Squid cache when this
3545          * page changes
3546          *
3547          * @return string[] Array of String the URLs
3548          */
3549         public function getSquidURLs() {
3550                 $urls = array(
3551                         $this->getInternalURL(),
3552                         $this->getInternalURL( 'action=history' )
3553                 );
3554
3555                 $pageLang = $this->getPageLanguage();
3556                 if ( $pageLang->hasVariants() ) {
3557                         $variants = $pageLang->getVariants();
3558                         foreach ( $variants as $vCode ) {
3559                                 $urls[] = $this->getInternalURL( '', $vCode );
3560                         }
3561                 }
3562
3563                 // If we are looking at a css/js user subpage, purge the action=raw.
3564                 if ( $this->isJsSubpage() ) {
3565                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3566                 } elseif ( $this->isCssSubpage() ) {
3567                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3568                 }
3569
3570                 Hooks::run( 'TitleSquidURLs', array( $this, &$urls ) );
3571                 return $urls;
3572         }
3573
3574         /**
3575          * Purge all applicable Squid URLs
3576          */
3577         public function purgeSquid() {
3578                 global $wgUseSquid;
3579                 if ( $wgUseSquid ) {
3580                         $urls = $this->getSquidURLs();
3581                         $u = new SquidUpdate( $urls );
3582                         $u->doUpdate();
3583                 }
3584         }
3585
3586         /**
3587          * Move this page without authentication
3588          *
3589          * @deprecated since 1.25 use MovePage class instead
3590          * @param Title $nt The new page Title
3591          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3592          */
3593         public function moveNoAuth( &$nt ) {
3594                 wfDeprecated( __METHOD__, '1.25' );
3595                 return $this->moveTo( $nt, false );
3596         }
3597
3598         /**
3599          * Check whether a given move operation would be valid.
3600          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3601          *
3602          * @deprecated since 1.25, use MovePage's methods instead
3603          * @param Title $nt The new title
3604          * @param bool $auth Whether to check user permissions (uses $wgUser)
3605          * @param string $reason Is the log summary of the move, used for spam checking
3606          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3607          */
3608         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3609                 global $wgUser;
3610
3611                 if ( !( $nt instanceof Title ) ) {
3612                         // Normally we'd add this to $errors, but we'll get
3613                         // lots of syntax errors if $nt is not an object
3614                         return array( array( 'badtitletext' ) );
3615                 }
3616
3617                 $mp = new MovePage( $this, $nt );
3618                 $errors = $mp->isValidMove()->getErrorsArray();
3619                 if ( $auth ) {
3620                         $errors = wfMergeErrorArrays(
3621                                 $errors,
3622                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3623                         );
3624                 }
3625
3626                 return $errors ? : true;
3627         }
3628
3629         /**
3630          * Check if the requested move target is a valid file move target
3631          * @todo move this to MovePage
3632          * @param Title $nt Target title
3633          * @return array List of errors
3634          */
3635         protected function validateFileMoveOperation( $nt ) {
3636                 global $wgUser;
3637
3638                 $errors = array();
3639
3640                 $destFile = wfLocalFile( $nt );
3641                 $destFile->load( File::READ_LATEST );
3642                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3643                         && !$destFile->exists() && wfFindFile( $nt )
3644                 ) {
3645                         $errors[] = array( 'file-exists-sharedrepo' );
3646                 }
3647
3648                 return $errors;
3649         }
3650
3651         /**
3652          * Move a title to a new location
3653          *
3654          * @deprecated since 1.25, use the MovePage class instead
3655          * @param Title $nt The new title
3656          * @param bool $auth Indicates whether $wgUser's permissions
3657          *  should be checked
3658          * @param string $reason The reason for the move
3659          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3660          *  Ignored if the user doesn't have the suppressredirect right.
3661          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3662          */
3663         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3664                 global $wgUser;
3665                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3666                 if ( is_array( $err ) ) {
3667                         // Auto-block user's IP if the account was "hard" blocked
3668                         $wgUser->spreadAnyEditBlock();
3669                         return $err;
3670                 }
3671                 // Check suppressredirect permission
3672                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3673                         $createRedirect = true;
3674                 }
3675
3676                 $mp = new MovePage( $this, $nt );
3677                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3678                 if ( $status->isOK() ) {
3679                         return true;
3680                 } else {
3681                         return $status->getErrorsArray();
3682                 }
3683         }
3684
3685         /**
3686          * Move this page's subpages to be subpages of $nt
3687          *
3688          * @param Title $nt Move target
3689          * @param bool $auth Whether $wgUser's permissions should be checked
3690          * @param string $reason The reason for the move
3691          * @param bool $createRedirect Whether to create redirects from the old subpages to
3692          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3693          * @return array Array with old page titles as keys, and strings (new page titles) or
3694          *     arrays (errors) as values, or an error array with numeric indices if no pages
3695          *     were moved
3696          */
3697         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3698                 global $wgMaximumMovedPages;
3699                 // Check permissions
3700                 if ( !$this->userCan( 'move-subpages' ) ) {
3701                         return array( 'cant-move-subpages' );
3702                 }
3703                 // Do the source and target namespaces support subpages?
3704                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3705                         return array( 'namespace-nosubpages',
3706                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3707                 }
3708                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3709                         return array( 'namespace-nosubpages',
3710                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3711                 }
3712
3713                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3714                 $retval = array();
3715                 $count = 0;
3716                 foreach ( $subpages as $oldSubpage ) {
3717                         $count++;
3718                         if ( $count > $wgMaximumMovedPages ) {
3719                                 $retval[$oldSubpage->getPrefixedText()] =
3720                                                 array( 'movepage-max-pages',
3721                                                         $wgMaximumMovedPages );
3722                                 break;
3723                         }
3724
3725                         // We don't know whether this function was called before
3726                         // or after moving the root page, so check both
3727                         // $this and $nt
3728                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3729                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3730                         ) {
3731                                 // When moving a page to a subpage of itself,
3732                                 // don't move it twice
3733                                 continue;
3734                         }
3735                         $newPageName = preg_replace(
3736                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3737                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3738                                         $oldSubpage->getDBkey() );
3739                         if ( $oldSubpage->isTalkPage() ) {
3740                                 $newNs = $nt->getTalkPage()->getNamespace();
3741                         } else {
3742                                 $newNs = $nt->getSubjectPage()->getNamespace();
3743                         }
3744                         # Bug 14385: we need makeTitleSafe because the new page names may
3745                         # be longer than 255 characters.
3746                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3747
3748                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3749                         if ( $success === true ) {
3750                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3751                         } else {
3752                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3753                         }
3754                 }
3755                 return $retval;
3756         }
3757
3758         /**
3759          * Checks if this page is just a one-rev redirect.
3760          * Adds lock, so don't use just for light purposes.
3761          *
3762          * @return bool
3763          */
3764         public function isSingleRevRedirect() {
3765                 global $wgContentHandlerUseDB;
3766
3767                 $dbw = wfGetDB( DB_MASTER );
3768
3769                 # Is it a redirect?
3770                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
3771                 if ( $wgContentHandlerUseDB ) {
3772                         $fields[] = 'page_content_model';
3773                 }
3774
3775                 $row = $dbw->selectRow( 'page',
3776                         $fields,
3777                         $this->pageCond(),
3778                         __METHOD__,
3779                         array( 'FOR UPDATE' )
3780                 );
3781                 # Cache some fields we may want
3782                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3783                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3784                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3785                 $this->mContentModel = $row && isset( $row->page_content_model )
3786                         ? strval( $row->page_content_model )
3787                         : false;
3788
3789                 if ( !$this->mRedirect ) {
3790                         return false;
3791                 }
3792                 # Does the article have a history?
3793                 $row = $dbw->selectField( array( 'page', 'revision' ),
3794                         'rev_id',
3795                         array( 'page_namespace' => $this->getNamespace(),
3796                                 'page_title' => $this->getDBkey(),
3797                                 'page_id=rev_page',
3798                                 'page_latest != rev_id'
3799                         ),
3800                         __METHOD__,
3801                         array( 'FOR UPDATE' )
3802                 );
3803                 # Return true if there was no history
3804                 return ( $row === false );
3805         }
3806
3807         /**
3808          * Checks if $this can be moved to a given Title
3809          * - Selects for update, so don't call it unless you mean business
3810          *
3811          * @deprecated since 1.25, use MovePage's methods instead
3812          * @param Title $nt The new title to check
3813          * @return bool
3814          */
3815         public function isValidMoveTarget( $nt ) {
3816                 # Is it an existing file?
3817                 if ( $nt->getNamespace() == NS_FILE ) {
3818                         $file = wfLocalFile( $nt );
3819                         $file->load( File::READ_LATEST );
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                         return $dbr->selectRowCount( 'revision', '1',
4102                                 $conds,
4103                                 __METHOD__,
4104                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4105                         );
4106                 } else {
4107                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4108                 }
4109         }
4110
4111         /**
4112          * Get the authors between the given revisions or revision IDs.
4113          * Used for diffs and other things that really need it.
4114          *
4115          * @since 1.23
4116          *
4117          * @param int|Revision $old Old revision or rev ID (first before range by default)
4118          * @param int|Revision $new New revision or rev ID (first after range by default)
4119          * @param int $limit Maximum number of authors
4120          * @param string|array $options (Optional): Single option, or an array of options:
4121          *     'include_old' Include $old in the range; $new is excluded.
4122          *     'include_new' Include $new in the range; $old is excluded.
4123          *     'include_both' Include both $old and $new in the range.
4124          *     Unknown option values are ignored.
4125          * @return array|null Names of revision authors in the range; null if not both revisions exist
4126          */
4127         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4128                 if ( !( $old instanceof Revision ) ) {
4129                         $old = Revision::newFromTitle( $this, (int)$old );
4130                 }
4131                 if ( !( $new instanceof Revision ) ) {
4132                         $new = Revision::newFromTitle( $this, (int)$new );
4133                 }
4134                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4135                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4136                 // in the sanity check below?
4137                 if ( !$old || !$new ) {
4138                         return null; // nothing to compare
4139                 }
4140                 $authors = array();
4141                 $old_cmp = '>';
4142                 $new_cmp = '<';
4143                 $options = (array)$options;
4144                 if ( in_array( 'include_old', $options ) ) {
4145                         $old_cmp = '>=';
4146                 }
4147                 if ( in_array( 'include_new', $options ) ) {
4148                         $new_cmp = '<=';
4149                 }
4150                 if ( in_array( 'include_both', $options ) ) {
4151                         $old_cmp = '>=';
4152                         $new_cmp = '<=';
4153                 }
4154                 // No DB query needed if $old and $new are the same or successive revisions:
4155                 if ( $old->getId() === $new->getId() ) {
4156                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4157                                 array() :
4158                                 array( $old->getUserText( Revision::RAW ) );
4159                 } elseif ( $old->getId() === $new->getParentId() ) {
4160                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4161                                 $authors[] = $old->getUserText( Revision::RAW );
4162                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4163                                         $authors[] = $new->getUserText( Revision::RAW );
4164                                 }
4165                         } elseif ( $old_cmp === '>=' ) {
4166                                 $authors[] = $old->getUserText( Revision::RAW );
4167                         } elseif ( $new_cmp === '<=' ) {
4168                                 $authors[] = $new->getUserText( Revision::RAW );
4169                         }
4170                         return $authors;
4171                 }
4172                 $dbr = wfGetDB( DB_SLAVE );
4173                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4174                         array(
4175                                 'rev_page' => $this->getArticleID(),
4176                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4177                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4178                         ), __METHOD__,
4179                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4180                 );
4181                 foreach ( $res as $row ) {
4182                         $authors[] = $row->rev_user_text;
4183                 }
4184                 return $authors;
4185         }
4186
4187         /**
4188          * Get the number of authors between the given revisions or revision IDs.
4189          * Used for diffs and other things that really need it.
4190          *
4191          * @param int|Revision $old Old revision or rev ID (first before range by default)
4192          * @param int|Revision $new New revision or rev ID (first after range by default)
4193          * @param int $limit Maximum number of authors
4194          * @param string|array $options (Optional): Single option, or an array of options:
4195          *     'include_old' Include $old in the range; $new is excluded.
4196          *     'include_new' Include $new in the range; $old is excluded.
4197          *     'include_both' Include both $old and $new in the range.
4198          *     Unknown option values are ignored.
4199          * @return int Number of revision authors in the range; zero if not both revisions exist
4200          */
4201         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4202                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4203                 return $authors ? count( $authors ) : 0;
4204         }
4205
4206         /**
4207          * Compare with another title.
4208          *
4209          * @param Title $title
4210          * @return bool
4211          */
4212         public function equals( Title $title ) {
4213                 // Note: === is necessary for proper matching of number-like titles.
4214                 return $this->getInterwiki() === $title->getInterwiki()
4215                         && $this->getNamespace() == $title->getNamespace()
4216                         && $this->getDBkey() === $title->getDBkey();
4217         }
4218
4219         /**
4220          * Check if this title is a subpage of another title
4221          *
4222          * @param Title $title
4223          * @return bool
4224          */
4225         public function isSubpageOf( Title $title ) {
4226                 return $this->getInterwiki() === $title->getInterwiki()
4227                         && $this->getNamespace() == $title->getNamespace()
4228                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4229         }
4230
4231         /**
4232          * Check if page exists.  For historical reasons, this function simply
4233          * checks for the existence of the title in the page table, and will
4234          * thus return false for interwiki links, special pages and the like.
4235          * If you want to know if a title can be meaningfully viewed, you should
4236          * probably call the isKnown() method instead.
4237          *
4238          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4239          *   from master/for update
4240          * @return bool
4241          */
4242         public function exists( $flags = 0 ) {
4243                 $exists = $this->getArticleID( $flags ) != 0;
4244                 Hooks::run( 'TitleExists', array( $this, &$exists ) );
4245                 return $exists;
4246         }
4247
4248         /**
4249          * Should links to this title be shown as potentially viewable (i.e. as
4250          * "bluelinks"), even if there's no record by this title in the page
4251          * table?
4252          *
4253          * This function is semi-deprecated for public use, as well as somewhat
4254          * misleadingly named.  You probably just want to call isKnown(), which
4255          * calls this function internally.
4256          *
4257          * (ISSUE: Most of these checks are cheap, but the file existence check
4258          * can potentially be quite expensive.  Including it here fixes a lot of
4259          * existing code, but we might want to add an optional parameter to skip
4260          * it and any other expensive checks.)
4261          *
4262          * @return bool
4263          */
4264         public function isAlwaysKnown() {
4265                 $isKnown = null;
4266
4267                 /**
4268                  * Allows overriding default behavior for determining if a page exists.
4269                  * If $isKnown is kept as null, regular checks happen. If it's
4270                  * a boolean, this value is returned by the isKnown method.
4271                  *
4272                  * @since 1.20
4273                  *
4274                  * @param Title $title
4275                  * @param bool|null $isKnown
4276                  */
4277                 Hooks::run( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4278
4279                 if ( !is_null( $isKnown ) ) {
4280                         return $isKnown;
4281                 }
4282
4283                 if ( $this->isExternal() ) {
4284                         return true;  // any interwiki link might be viewable, for all we know
4285                 }
4286
4287                 switch ( $this->mNamespace ) {
4288                         case NS_MEDIA:
4289                         case NS_FILE:
4290                                 // file exists, possibly in a foreign repo
4291                                 return (bool)wfFindFile( $this );
4292                         case NS_SPECIAL:
4293                                 // valid special page
4294                                 return SpecialPageFactory::exists( $this->getDBkey() );
4295                         case NS_MAIN:
4296                                 // selflink, possibly with fragment
4297                                 return $this->mDbkeyform == '';
4298                         case NS_MEDIAWIKI:
4299                                 // known system message
4300                                 return $this->hasSourceText() !== false;
4301                         default:
4302                                 return false;
4303                 }
4304         }
4305
4306         /**
4307          * Does this title refer to a page that can (or might) be meaningfully
4308          * viewed?  In particular, this function may be used to determine if
4309          * links to the title should be rendered as "bluelinks" (as opposed to
4310          * "redlinks" to non-existent pages).
4311          * Adding something else to this function will cause inconsistency
4312          * since LinkHolderArray calls isAlwaysKnown() and does its own
4313          * page existence check.
4314          *
4315          * @return bool
4316          */
4317         public function isKnown() {
4318                 return $this->isAlwaysKnown() || $this->exists();
4319         }
4320
4321         /**
4322          * Does this page have source text?
4323          *
4324          * @return bool
4325          */
4326         public function hasSourceText() {
4327                 if ( $this->exists() ) {
4328                         return true;
4329                 }
4330
4331                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4332                         // If the page doesn't exist but is a known system message, default
4333                         // message content will be displayed, same for language subpages-
4334                         // Use always content language to avoid loading hundreds of languages
4335                         // to get the link color.
4336                         global $wgContLang;
4337                         list( $name, ) = MessageCache::singleton()->figureMessage(
4338                                 $wgContLang->lcfirst( $this->getText() )
4339                         );
4340                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4341                         return $message->exists();
4342                 }
4343
4344                 return false;
4345         }
4346
4347         /**
4348          * Get the default message text or false if the message doesn't exist
4349          *
4350          * @return string|bool
4351          */
4352         public function getDefaultMessageText() {
4353                 global $wgContLang;
4354
4355                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4356                         return false;
4357                 }
4358
4359                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4360                         $wgContLang->lcfirst( $this->getText() )
4361                 );
4362                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4363
4364                 if ( $message->exists() ) {
4365                         return $message->plain();
4366                 } else {
4367                         return false;
4368                 }
4369         }
4370
4371         /**
4372          * Updates page_touched for this page; called from LinksUpdate.php
4373          *
4374          * @return bool True if the update succeeded
4375          */
4376         public function invalidateCache() {
4377                 if ( wfReadOnly() ) {
4378                         return false;
4379                 }
4380
4381                 if ( $this->mArticleID === 0 ) {
4382                         return true; // avoid gap locking if we know it's not there
4383                 }
4384
4385                 $method = __METHOD__;
4386                 $dbw = wfGetDB( DB_MASTER );
4387                 $conds = $this->pageCond();
4388                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method ) {
4389                         $dbw->update(
4390                                 'page',
4391                                 array( 'page_touched' => $dbw->timestamp() ),
4392                                 $conds,
4393                                 $method
4394                         );
4395                 } );
4396
4397                 return true;
4398         }
4399
4400         /**
4401          * Update page_touched timestamps and send squid purge messages for
4402          * pages linking to this title. May be sent to the job queue depending
4403          * on the number of links. Typically called on create and delete.
4404          */
4405         public function touchLinks() {
4406                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4407                 $u->doUpdate();
4408
4409                 if ( $this->getNamespace() == NS_CATEGORY ) {
4410                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4411                         $u->doUpdate();
4412                 }
4413         }
4414
4415         /**
4416          * Get the last touched timestamp
4417          *
4418          * @param DatabaseBase $db Optional db
4419          * @return string Last-touched timestamp
4420          */
4421         public function getTouched( $db = null ) {
4422                 if ( $db === null ) {
4423                         $db = wfGetDB( DB_SLAVE );
4424                 }
4425                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4426                 return $touched;
4427         }
4428
4429         /**
4430          * Get the timestamp when this page was updated since the user last saw it.
4431          *
4432          * @param User $user
4433          * @return string|null
4434          */
4435         public function getNotificationTimestamp( $user = null ) {
4436                 global $wgUser;
4437
4438                 // Assume current user if none given
4439                 if ( !$user ) {
4440                         $user = $wgUser;
4441                 }
4442                 // Check cache first
4443                 $uid = $user->getId();
4444                 if ( !$uid ) {
4445                         return false;
4446                 }
4447                 // avoid isset here, as it'll return false for null entries
4448                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4449                         return $this->mNotificationTimestamp[$uid];
4450                 }
4451                 // Don't cache too much!
4452                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4453                         $this->mNotificationTimestamp = array();
4454                 }
4455
4456                 $watchedItem = WatchedItem::fromUserTitle( $user, $this );
4457                 $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4458
4459                 return $this->mNotificationTimestamp[$uid];
4460         }
4461
4462         /**
4463          * Generate strings used for xml 'id' names in monobook tabs
4464          *
4465          * @param string $prepend Defaults to 'nstab-'
4466          * @return string XML 'id' name
4467          */
4468         public function getNamespaceKey( $prepend = 'nstab-' ) {
4469                 global $wgContLang;
4470                 // Gets the subject namespace if this title
4471                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4472                 // Checks if canonical namespace name exists for namespace
4473                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4474                         // Uses canonical namespace name
4475                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4476                 } else {
4477                         // Uses text of namespace
4478                         $namespaceKey = $this->getSubjectNsText();
4479                 }
4480                 // Makes namespace key lowercase
4481                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4482                 // Uses main
4483                 if ( $namespaceKey == '' ) {
4484                         $namespaceKey = 'main';
4485                 }
4486                 // Changes file to image for backwards compatibility
4487                 if ( $namespaceKey == 'file' ) {
4488                         $namespaceKey = 'image';
4489                 }
4490                 return $prepend . $namespaceKey;
4491         }
4492
4493         /**
4494          * Get all extant redirects to this Title
4495          *
4496          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4497          * @return Title[] Array of Title redirects to this title
4498          */
4499         public function getRedirectsHere( $ns = null ) {
4500                 $redirs = array();
4501
4502                 $dbr = wfGetDB( DB_SLAVE );
4503                 $where = array(
4504                         'rd_namespace' => $this->getNamespace(),
4505                         'rd_title' => $this->getDBkey(),
4506                         'rd_from = page_id'
4507                 );
4508                 if ( $this->isExternal() ) {
4509                         $where['rd_interwiki'] = $this->getInterwiki();
4510                 } else {
4511                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4512                 }
4513                 if ( !is_null( $ns ) ) {
4514                         $where['page_namespace'] = $ns;
4515                 }
4516
4517                 $res = $dbr->select(
4518                         array( 'redirect', 'page' ),
4519                         array( 'page_namespace', 'page_title' ),
4520                         $where,
4521                         __METHOD__
4522                 );
4523
4524                 foreach ( $res as $row ) {
4525                         $redirs[] = self::newFromRow( $row );
4526                 }
4527                 return $redirs;
4528         }
4529
4530         /**
4531          * Check if this Title is a valid redirect target
4532          *
4533          * @return bool
4534          */
4535         public function isValidRedirectTarget() {
4536                 global $wgInvalidRedirectTargets;
4537
4538                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4539                 if ( $this->isSpecial( 'Userlogout' ) ) {
4540                         return false;
4541                 }
4542
4543                 foreach ( $wgInvalidRedirectTargets as $target ) {
4544                         if ( $this->isSpecial( $target ) ) {
4545                                 return false;
4546                         }
4547                 }
4548
4549                 return true;
4550         }
4551
4552         /**
4553          * Get a backlink cache object
4554          *
4555          * @return BacklinkCache
4556          */
4557         public function getBacklinkCache() {
4558                 return BacklinkCache::get( $this );
4559         }
4560
4561         /**
4562          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4563          *
4564          * @return bool
4565          */
4566         public function canUseNoindex() {
4567                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4568
4569                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4570                         ? $wgContentNamespaces
4571                         : $wgExemptFromUserRobotsControl;
4572
4573                 return !in_array( $this->mNamespace, $bannedNamespaces );
4574
4575         }
4576
4577         /**
4578          * Returns the raw sort key to be used for categories, with the specified
4579          * prefix.  This will be fed to Collation::getSortKey() to get a
4580          * binary sortkey that can be used for actual sorting.
4581          *
4582          * @param string $prefix The prefix to be used, specified using
4583          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4584          *   prefix.
4585          * @return string
4586          */
4587         public function getCategorySortkey( $prefix = '' ) {
4588                 $unprefixed = $this->getText();
4589
4590                 // Anything that uses this hook should only depend
4591                 // on the Title object passed in, and should probably
4592                 // tell the users to run updateCollations.php --force
4593                 // in order to re-sort existing category relations.
4594                 Hooks::run( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4595                 if ( $prefix !== '' ) {
4596                         # Separate with a line feed, so the unprefixed part is only used as
4597                         # a tiebreaker when two pages have the exact same prefix.
4598                         # In UCA, tab is the only character that can sort above LF
4599                         # so we strip both of them from the original prefix.
4600                         $prefix = strtr( $prefix, "\n\t", '  ' );
4601                         return "$prefix\n$unprefixed";
4602                 }
4603                 return $unprefixed;
4604         }
4605
4606         /**
4607          * Get the language in which the content of this page is written in
4608          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4609          * e.g. $wgLang (such as special pages, which are in the user language).
4610          *
4611          * @since 1.18
4612          * @return Language
4613          */
4614         public function getPageLanguage() {
4615                 global $wgLang, $wgLanguageCode;
4616                 if ( $this->isSpecialPage() ) {
4617                         // special pages are in the user language
4618                         return $wgLang;
4619                 }
4620
4621                 // Checking if DB language is set
4622                 if ( $this->mDbPageLanguage ) {
4623                         return wfGetLangObj( $this->mDbPageLanguage );
4624                 }
4625
4626                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4627                         // Note that this may depend on user settings, so the cache should
4628                         // be only per-request.
4629                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4630                         // content to determine the page language!
4631                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4632                         // tests.
4633                         $contentHandler = ContentHandler::getForTitle( $this );
4634                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4635                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4636                 } else {
4637                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4638                 }
4639
4640                 return $langObj;
4641         }
4642
4643         /**
4644          * Get the language in which the content of this page is written when
4645          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4646          * e.g. $wgLang (such as special pages, which are in the user language).
4647          *
4648          * @since 1.20
4649          * @return Language
4650          */
4651         public function getPageViewLanguage() {
4652                 global $wgLang;
4653
4654                 if ( $this->isSpecialPage() ) {
4655                         // If the user chooses a variant, the content is actually
4656                         // in a language whose code is the variant code.
4657                         $variant = $wgLang->getPreferredVariant();
4658                         if ( $wgLang->getCode() !== $variant ) {
4659                                 return Language::factory( $variant );
4660                         }
4661
4662                         return $wgLang;
4663                 }
4664
4665                 // @note Can't be cached persistently, depends on user settings.
4666                 // @note ContentHandler::getPageViewLanguage() may need to load the
4667                 //   content to determine the page language!
4668                 $contentHandler = ContentHandler::getForTitle( $this );
4669                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4670                 return $pageLang;
4671         }
4672
4673         /**
4674          * Get a list of rendered edit notices for this page.
4675          *
4676          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4677          * they will already be wrapped in paragraphs.
4678          *
4679          * @since 1.21
4680          * @param int $oldid Revision ID that's being edited
4681          * @return array
4682          */
4683         public function getEditNotices( $oldid = 0 ) {
4684                 $notices = array();
4685
4686                 // Optional notice for the entire namespace
4687                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4688                 $msg = wfMessage( $editnotice_ns );
4689                 if ( $msg->exists() ) {
4690                         $html = $msg->parseAsBlock();
4691                         // Edit notices may have complex logic, but output nothing (T91715)
4692                         if ( trim( $html ) !== '' ) {
4693                                 $notices[$editnotice_ns] = Html::rawElement(
4694                                         'div',
4695                                         array( 'class' => array(
4696                                                 'mw-editnotice',
4697                                                 'mw-editnotice-namespace',
4698                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4699                                         ) ),
4700                                         $html
4701                                 );
4702                         }
4703                 }
4704
4705                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4706                         // Optional notice for page itself and any parent page
4707                         $parts = explode( '/', $this->getDBkey() );
4708                         $editnotice_base = $editnotice_ns;
4709                         while ( count( $parts ) > 0 ) {
4710                                 $editnotice_base .= '-' . array_shift( $parts );
4711                                 $msg = wfMessage( $editnotice_base );
4712                                 if ( $msg->exists() ) {
4713                                         $html = $msg->parseAsBlock();
4714                                         if ( trim( $html ) !== '' ) {
4715                                                 $notices[$editnotice_base] = Html::rawElement(
4716                                                         'div',
4717                                                         array( 'class' => array(
4718                                                                 'mw-editnotice',
4719                                                                 'mw-editnotice-base',
4720                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4721                                                         ) ),
4722                                                         $html
4723                                                 );
4724                                         }
4725                                 }
4726                         }
4727                 } else {
4728                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4729                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
4730                         $msg = wfMessage( $editnoticeText );
4731                         if ( $msg->exists() ) {
4732                                 $html = $msg->parseAsBlock();
4733                                 if ( trim( $html ) !== '' ) {
4734                                         $notices[$editnoticeText] = Html::rawElement(
4735                                                 'div',
4736                                                 array( 'class' => array(
4737                                                         'mw-editnotice',
4738                                                         'mw-editnotice-page',
4739                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4740                                                 ) ),
4741                                                 $html
4742                                         );
4743                                 }
4744                         }
4745                 }
4746
4747                 Hooks::run( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4748                 return $notices;
4749         }
4750 }