includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 /**
  26  * Represents a title within MediaWiki.
  27  * Optionally may contain an interwiki designation or namespace.
  28  * @note This class can fetch various kinds of data from the database;
  29  *       however, it does so inefficiently.
  30  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  31  *       and does not rely on global state or the database.
  32  */
  33 class Title {
  34         /** @var MapCacheLRU */
  35         static private $titleCache = null;
  36
  37         /**
  38          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  39          * commonly used titles. On a batch operation this can become a memory leak
  40          * if not bounded. After hitting this many titles reset the cache.
  41          */
  42         const CACHE_MAX = 1000;
  43
  44         /**
  45          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  46          * to use the master DB
  47          */
  48         const GAID_FOR_UPDATE = 1;
  49
  50         /**
  51          * @name Private member variables
  52          * Please use the accessor functions instead.
  53          * @private
  54          */
  55         // @{
  56
  57         /** @var string Text form (spaces not underscores) of the main part */
  58         public $mTextform = '';
  59
  60         /** @var string URL-encoded form of the main part */
  61         public $mUrlform = '';
  62
  63         /** @var string Main part with underscores */
  64         public $mDbkeyform = '';
  65
  66         /** @var string Database key with the initial letter in the case specified by the user */
  67         protected $mUserCaseDBKey;
  68
  69         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  70         public $mNamespace = NS_MAIN;
  71
  72         /** @var string Interwiki prefix */
  73         public $mInterwiki = '';
  74
  75         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  76         private $mLocalInterwiki = false;
  77
  78         /** @var string Title fragment (i.e. the bit after the #) */
  79         public $mFragment = '';
  80
  81         /** @var int Article ID, fetched from the link cache on demand */
  82         public $mArticleID = -1;
  83
  84         /** @var bool|int ID of most recent revision */
  85         protected $mLatestID = false;
  86
  87         /**
  88          * @var bool|string ID of the page's content model, i.e. one of the
  89          *   CONTENT_MODEL_XXX constants
  90          */
  91         public $mContentModel = false;
  92
  93         /** @var int Estimated number of revisions; null of not loaded */
  94         private $mEstimateRevisions;
  95
  96         /** @var array Array of groups allowed to edit this article */
  97         public $mRestrictions = array();
  98
  99         /** @var string|bool */
 100         protected $mOldRestrictions = false;
 101
 102         /** @var bool Cascade restrictions on this page to included templates and images? */
 103         public $mCascadeRestriction;
 104
 105         /** Caching the results of getCascadeProtectionSources */
 106         public $mCascadingRestrictions;
 107
 108         /** @var array When do the restrictions on this page expire? */
 109         protected $mRestrictionsExpiry = array();
 110
 111         /** @var bool Are cascading restrictions in effect on this page? */
 112         protected $mHasCascadingRestrictions;
 113
 114         /** @var array Where are the cascading restrictions coming from on this page? */
 115         public $mCascadeSources;
 116
 117         /** @var bool Boolean for initialisation on demand */
 118         public $mRestrictionsLoaded = false;
 119
 120         /** @var string Text form including namespace/interwiki, initialised on demand */
 121         protected $mPrefixedText = null;
 122
 123         /** @var mixed Cached value for getTitleProtection (create protection) */
 124         public $mTitleProtection;
 125
 126         /**
 127          * @var int Namespace index when there is no namespace. Don't change the
 128          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 129          *   Zero except in {{transclusion}} tags.
 130          */
 131         public $mDefaultNamespace = NS_MAIN;
 132
 133         /**
 134          * @var bool Is $wgUser watching this page? null if unfilled, accessed
 135          * through userIsWatching()
 136          */
 137         protected $mWatched = null;
 138
 139         /** @var int The page length, 0 for special pages */
 140         protected $mLength = -1;
 141
 142         /** @var null Is the article at this title a redirect? */
 143         public $mRedirect = null;
 144
 145         /** @var array Associative array of user ID -> timestamp/false */
 146         private $mNotificationTimestamp = array();
 147
 148         /** @var bool Whether a page has any subpages */
 149         private $mHasSubpages;
 150
 151         /** @var bool The (string) language code of the page's language and content code. */
 152         private $mPageLanguage = false;
 153
 154         /** @var string The page language code from the database */
 155         private $mDbPageLanguage = null;
 156
 157         /** @var TitleValue A corresponding TitleValue object */
 158         private $mTitleValue = null;
 159
 160         /** @var bool Would deleting this page be a big deletion? */
 161         private $mIsBigDeletion = null;
 162         // @}
 163
 164         /**
 165          * B/C kludge: provide a TitleParser for use by Title.
 166          * Ideally, Title would have no methods that need this.
 167          * Avoid usage of this singleton by using TitleValue
 168          * and the associated services when possible.
 169          *
 170          * @return TitleParser
 171          */
 172         private static function getTitleParser() {
 173                 global $wgContLang, $wgLocalInterwikis;
 174
 175                 static $titleCodec = null;
 176                 static $titleCodecFingerprint = null;
 177
 178                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 179                 // make sure we are using the right one. To detect changes over the course
 180                 // of a request, we remember a fingerprint of the config used to create the
 181                 // codec singleton, and re-create it if the fingerprint doesn't match.
 182                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . join( '+', $wgLocalInterwikis );
 183
 184                 if ( $fingerprint !== $titleCodecFingerprint ) {
 185                         $titleCodec = null;
 186                 }
 187
 188                 if ( !$titleCodec ) {
 189                         $titleCodec = new MediaWikiTitleCodec(
 190                                 $wgContLang,
 191                                 GenderCache::singleton(),
 192                                 $wgLocalInterwikis
 193                         );
 194                         $titleCodecFingerprint = $fingerprint;
 195                 }
 196
 197                 return $titleCodec;
 198         }
 199
 200         /**
 201          * B/C kludge: provide a TitleParser for use by Title.
 202          * Ideally, Title would have no methods that need this.
 203          * Avoid usage of this singleton by using TitleValue
 204          * and the associated services when possible.
 205          *
 206          * @return TitleFormatter
 207          */
 208         private static function getTitleFormatter() {
 209                 // NOTE: we know that getTitleParser() returns a MediaWikiTitleCodec,
 210                 //      which implements TitleFormatter.
 211                 return self::getTitleParser();
 212         }
 213
 214         function __construct() {
 215         }
 216
 217         /**
 218          * Create a new Title from a prefixed DB key
 219          *
 220          * @param string $key The database key, which has underscores
 221          *      instead of spaces, possibly including namespace and
 222          *      interwiki prefixes
 223          * @return Title|null Title, or null on an error
 224          */
 225         public static function newFromDBkey( $key ) {
 226                 $t = new Title();
 227                 $t->mDbkeyform = $key;
 228
 229                 try {
 230                         $t->secureAndSplit();
 231                         return $t;
 232                 } catch ( MalformedTitleException $ex ) {
 233                         return null;
 234                 }
 235         }
 236
 237         /**
 238          * Create a new Title from a TitleValue
 239          *
 240          * @param TitleValue $titleValue Assumed to be safe.
 241          *
 242          * @return Title
 243          */
 244         public static function newFromTitleValue( TitleValue $titleValue ) {
 245                 return self::makeTitle(
 246                         $titleValue->getNamespace(),
 247                         $titleValue->getText(),
 248                         $titleValue->getFragment() );
 249         }
 250
 251         /**
 252          * Create a new Title from text, such as what one would find in a link. De-
 253          * codes any HTML entities in the text.
 254          *
 255          * @param string $text The link text; spaces, prefixes, and an
 256          *   initial ':' indicating the main namespace are accepted.
 257          * @param int $defaultNamespace The namespace to use if none is specified
 258          *   by a prefix.  If you want to force a specific namespace even if
 259          *   $text might begin with a namespace prefix, use makeTitle() or
 260          *   makeTitleSafe().
 261          * @throws InvalidArgumentException
 262          * @return Title|null Title or null on an error.
 263          */
 264         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 265                 if ( is_object( $text ) ) {
 266                         throw new InvalidArgumentException( '$text must be a string.' );
 267                 } elseif ( !is_string( $text ) ) {
 268                         wfDebugLog( 'T76305', wfGetAllCallers( 5 ) );
 269                         wfWarn(
 270                                 __METHOD__ . ': $text must be a string. ' .
 271                                         'This will throw an InvalidArgumentException in future.',
 272                                 2
 273                         );
 274                 }
 275
 276                 try {
 277                         return Title::newFromTextThrow( $text, $defaultNamespace );
 278                 } catch ( MalformedTitleException $ex ) {
 279                         return null;
 280                 }
 281         }
 282
 283         /**
 284          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 285          * rather than returning null.
 286          *
 287          * The exception subclasses encode detailed information about why the title is invalid.
 288          *
 289          * @see Title::newFromText
 290          *
 291          * @since 1.25
 292          * @param string $text Title text to check
 293          * @param int $defaultNamespace
 294          * @throws MalformedTitleException If the title is invalid
 295          * @return Title
 296          */
 297         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 298                 if ( is_object( $text ) ) {
 299                         throw new MWException( 'Title::newFromTextThrow given an object' );
 300                 }
 301
 302                 $cache = self::getTitleCache();
 303
 304                 /**
 305                  * Wiki pages often contain multiple links to the same page.
 306                  * Title normalization and parsing can become expensive on
 307                  * pages with many links, so we can save a little time by
 308                  * caching them.
 309                  *
 310                  * In theory these are value objects and won't get changed...
 311                  */
 312                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 313                         return $cache->get( $text );
 314                 }
 315
 316                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 317                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 318
 319                 $t = new Title();
 320                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 321                 $t->mDefaultNamespace = intval( $defaultNamespace );
 322
 323                 $t->secureAndSplit();
 324                 if ( $defaultNamespace == NS_MAIN ) {
 325                         $cache->set( $text, $t );
 326                 }
 327                 return $t;
 328         }
 329
 330         /**
 331          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 332          *
 333          * Example of wrong and broken code:
 334          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 335          *
 336          * Example of right code:
 337          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 338          *
 339          * Create a new Title from URL-encoded text. Ensures that
 340          * the given title's length does not exceed the maximum.
 341          *
 342          * @param string $url The title, as might be taken from a URL
 343          * @return Title|null The new object, or null on an error
 344          */
 345         public static function newFromURL( $url ) {
 346                 $t = new Title();
 347
 348                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 349                 # but some URLs used it as a space replacement and they still come
 350                 # from some external search tools.
 351                 if ( strpos( self::legalChars(), '+' ) === false ) {
 352                         $url = strtr( $url, '+', ' ' );
 353                 }
 354
 355                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 356
 357                 try {
 358                         $t->secureAndSplit();
 359                         return $t;
 360                 } catch ( MalformedTitleException $ex ) {
 361                         return null;
 362                 }
 363         }
 364
 365         /**
 366          * @return MapCacheLRU
 367          */
 368         private static function getTitleCache() {
 369                 if ( self::$titleCache == null ) {
 370                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 371                 }
 372                 return self::$titleCache;
 373         }
 374
 375         /**
 376          * Returns a list of fields that are to be selected for initializing Title
 377          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 378          * whether to include page_content_model.
 379          *
 380          * @return array
 381          */
 382         protected static function getSelectFields() {
 383                 global $wgContentHandlerUseDB;
 384
 385                 $fields = array(
 386                         'page_namespace', 'page_title', 'page_id',
 387                         'page_len', 'page_is_redirect', 'page_latest',
 388                 );
 389
 390                 if ( $wgContentHandlerUseDB ) {
 391                         $fields[] = 'page_content_model';
 392                 }
 393
 394                 return $fields;
 395         }
 396
 397         /**
 398          * Create a new Title from an article ID
 399          *
 400          * @param int $id The page_id corresponding to the Title to create
 401          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 402          * @return Title|null The new object, or null on an error
 403          */
 404         public static function newFromID( $id, $flags = 0 ) {
 405                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 406                 $row = $db->selectRow(
 407                         'page',
 408                         self::getSelectFields(),
 409                         array( 'page_id' => $id ),
 410                         __METHOD__
 411                 );
 412                 if ( $row !== false ) {
 413                         $title = Title::newFromRow( $row );
 414                 } else {
 415                         $title = null;
 416                 }
 417                 return $title;
 418         }
 419
 420         /**
 421          * Make an array of titles from an array of IDs
 422          *
 423          * @param int[] $ids Array of IDs
 424          * @return Title[] Array of Titles
 425          */
 426         public static function newFromIDs( $ids ) {
 427                 if ( !count( $ids ) ) {
 428                         return array();
 429                 }
 430                 $dbr = wfGetDB( DB_SLAVE );
 431
 432                 $res = $dbr->select(
 433                         'page',
 434                         self::getSelectFields(),
 435                         array( 'page_id' => $ids ),
 436                         __METHOD__
 437                 );
 438
 439                 $titles = array();
 440                 foreach ( $res as $row ) {
 441                         $titles[] = Title::newFromRow( $row );
 442                 }
 443                 return $titles;
 444         }
 445
 446         /**
 447          * Make a Title object from a DB row
 448          *
 449          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 450          * @return Title Corresponding Title
 451          */
 452         public static function newFromRow( $row ) {
 453                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 454                 $t->loadFromRow( $row );
 455                 return $t;
 456         }
 457
 458         /**
 459          * Load Title object fields from a DB row.
 460          * If false is given, the title will be treated as non-existing.
 461          *
 462          * @param stdClass|bool $row Database row
 463          */
 464         public function loadFromRow( $row ) {
 465                 if ( $row ) { // page found
 466                         if ( isset( $row->page_id ) ) {
 467                                 $this->mArticleID = (int)$row->page_id;
 468                         }
 469                         if ( isset( $row->page_len ) ) {
 470                                 $this->mLength = (int)$row->page_len;
 471                         }
 472                         if ( isset( $row->page_is_redirect ) ) {
 473                                 $this->mRedirect = (bool)$row->page_is_redirect;
 474                         }
 475                         if ( isset( $row->page_latest ) ) {
 476                                 $this->mLatestID = (int)$row->page_latest;
 477                         }
 478                         if ( isset( $row->page_content_model ) ) {
 479                                 $this->mContentModel = strval( $row->page_content_model );
 480                         } else {
 481                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 482                         }
 483                         if ( isset( $row->page_lang ) ) {
 484                                 $this->mDbPageLanguage = (string)$row->page_lang;
 485                         }
 486                         if ( isset( $row->page_restrictions ) ) {
 487                                 $this->mOldRestrictions = $row->page_restrictions;
 488                         }
 489                 } else { // page not found
 490                         $this->mArticleID = 0;
 491                         $this->mLength = 0;
 492                         $this->mRedirect = false;
 493                         $this->mLatestID = 0;
 494                         $this->mContentModel = false; # initialized lazily in getContentModel()
 495                 }
 496         }
 497
 498         /**
 499          * Create a new Title from a namespace index and a DB key.
 500          * It's assumed that $ns and $title are *valid*, for instance when
 501          * they came directly from the database or a special page name.
 502          * For convenience, spaces are converted to underscores so that
 503          * eg user_text fields can be used directly.
 504          *
 505          * @param int $ns The namespace of the article
 506          * @param string $title The unprefixed database key form
 507          * @param string $fragment The link fragment (after the "#")
 508          * @param string $interwiki The interwiki prefix
 509          * @return Title The new object
 510          */
 511         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 512                 $t = new Title();
 513                 $t->mInterwiki = $interwiki;
 514                 $t->mFragment = $fragment;
 515                 $t->mNamespace = $ns = intval( $ns );
 516                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 517                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 518                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 519                 $t->mTextform = strtr( $title, '_', ' ' );
 520                 $t->mContentModel = false; # initialized lazily in getContentModel()
 521                 return $t;
 522         }
 523
 524         /**
 525          * Create a new Title from a namespace index and a DB key.
 526          * The parameters will be checked for validity, which is a bit slower
 527          * than makeTitle() but safer for user-provided data.
 528          *
 529          * @param int $ns The namespace of the article
 530          * @param string $title Database key form
 531          * @param string $fragment The link fragment (after the "#")
 532          * @param string $interwiki Interwiki prefix
 533          * @return Title|null The new object, or null on an error
 534          */
 535         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 536                 if ( !MWNamespace::exists( $ns ) ) {
 537                         return null;
 538                 }
 539
 540                 $t = new Title();
 541                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 542
 543                 try {
 544                         $t->secureAndSplit();
 545                         return $t;
 546                 } catch ( MalformedTitleException $ex ) {
 547                         return null;
 548                 }
 549         }
 550
 551         /**
 552          * Create a new Title for the Main Page
 553          *
 554          * @return Title The new object
 555          */
 556         public static function newMainPage() {
 557                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 558                 // Don't give fatal errors if the message is broken
 559                 if ( !$title ) {
 560                         $title = Title::newFromText( 'Main Page' );
 561                 }
 562                 return $title;
 563         }
 564
 565         /**
 566          * Extract a redirect destination from a string and return the
 567          * Title, or null if the text doesn't contain a valid redirect
 568          * This will only return the very next target, useful for
 569          * the redirect table and other checks that don't need full recursion
 570          *
 571          * @param string $text Text with possible redirect
 572          * @return Title The corresponding Title
 573          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 574          */
 575         public static function newFromRedirect( $text ) {
 576                 ContentHandler::deprecated( __METHOD__, '1.21' );
 577
 578                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 579                 return $content->getRedirectTarget();
 580         }
 581
 582         /**
 583          * Extract a redirect destination from a string and return the
 584          * Title, or null if the text doesn't contain a valid redirect
 585          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 586          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 587          *
 588          * @param string $text Text with possible redirect
 589          * @return Title
 590          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 591          */
 592         public static function newFromRedirectRecurse( $text ) {
 593                 ContentHandler::deprecated( __METHOD__, '1.21' );
 594
 595                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 596                 return $content->getUltimateRedirectTarget();
 597         }
 598
 599         /**
 600          * Extract a redirect destination from a string and return an
 601          * array of Titles, or null if the text doesn't contain a valid redirect
 602          * The last element in the array is the final destination after all redirects
 603          * have been resolved (up to $wgMaxRedirects times)
 604          *
 605          * @param string $text Text with possible redirect
 606          * @return Title[] Array of Titles, with the destination last
 607          * @deprecated since 1.21, use Content::getRedirectChain instead.
 608          */
 609         public static function newFromRedirectArray( $text ) {
 610                 ContentHandler::deprecated( __METHOD__, '1.21' );
 611
 612                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 613                 return $content->getRedirectChain();
 614         }
 615
 616         /**
 617          * Get the prefixed DB key associated with an ID
 618          *
 619          * @param int $id The page_id of the article
 620          * @return Title|null An object representing the article, or null if no such article was found
 621          */
 622         public static function nameOf( $id ) {
 623                 $dbr = wfGetDB( DB_SLAVE );
 624
 625                 $s = $dbr->selectRow(
 626                         'page',
 627                         array( 'page_namespace', 'page_title' ),
 628                         array( 'page_id' => $id ),
 629                         __METHOD__
 630                 );
 631                 if ( $s === false ) {
 632                         return null;
 633                 }
 634
 635                 $n = self::makeName( $s->page_namespace, $s->page_title );
 636                 return $n;
 637         }
 638
 639         /**
 640          * Get a regex character class describing the legal characters in a link
 641          *
 642          * @return string The list of characters, not delimited
 643          */
 644         public static function legalChars() {
 645                 global $wgLegalTitleChars;
 646                 return $wgLegalTitleChars;
 647         }
 648
 649         /**
 650          * Returns a simple regex that will match on characters and sequences invalid in titles.
 651          * Note that this doesn't pick up many things that could be wrong with titles, but that
 652          * replacing this regex with something valid will make many titles valid.
 653          *
 654          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 655          *
 656          * @return string Regex string
 657          */
 658         static function getTitleInvalidRegex() {
 659                 wfDeprecated( __METHOD__, '1.25' );
 660                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 661         }
 662
 663         /**
 664          * Utility method for converting a character sequence from bytes to Unicode.
 665          *
 666          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 667          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 668          *
 669          * @param string $byteClass
 670          * @return string
 671          */
 672         public static function convertByteClassToUnicodeClass( $byteClass ) {
 673                 $length = strlen( $byteClass );
 674                 // Input token queue
 675                 $x0 = $x1 = $x2 = '';
 676                 // Decoded queue
 677                 $d0 = $d1 = $d2 = '';
 678                 // Decoded integer codepoints
 679                 $ord0 = $ord1 = $ord2 = 0;
 680                 // Re-encoded queue
 681                 $r0 = $r1 = $r2 = '';
 682                 // Output
 683                 $out = '';
 684                 // Flags
 685                 $allowUnicode = false;
 686                 for ( $pos = 0; $pos < $length; $pos++ ) {
 687                         // Shift the queues down
 688                         $x2 = $x1;
 689                         $x1 = $x0;
 690                         $d2 = $d1;
 691                         $d1 = $d0;
 692                         $ord2 = $ord1;
 693                         $ord1 = $ord0;
 694                         $r2 = $r1;
 695                         $r1 = $r0;
 696                         // Load the current input token and decoded values
 697                         $inChar = $byteClass[$pos];
 698                         if ( $inChar == '\\' ) {
 699                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 700                                         $x0 = $inChar . $m[0];
 701                                         $d0 = chr( hexdec( $m[1] ) );
 702                                         $pos += strlen( $m[0] );
 703                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 704                                         $x0 = $inChar . $m[0];
 705                                         $d0 = chr( octdec( $m[0] ) );
 706                                         $pos += strlen( $m[0] );
 707                                 } elseif ( $pos + 1 >= $length ) {
 708                                         $x0 = $d0 = '\\';
 709                                 } else {
 710                                         $d0 = $byteClass[$pos + 1];
 711                                         $x0 = $inChar . $d0;
 712                                         $pos += 1;
 713                                 }
 714                         } else {
 715                                 $x0 = $d0 = $inChar;
 716                         }
 717                         $ord0 = ord( $d0 );
 718                         // Load the current re-encoded value
 719                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 720                                 $r0 = sprintf( '\x%02x', $ord0 );
 721                         } elseif ( $ord0 >= 0x80 ) {
 722                                 // Allow unicode if a single high-bit character appears
 723                                 $r0 = sprintf( '\x%02x', $ord0 );
 724                                 $allowUnicode = true;
 725                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 726                                 $r0 = '\\' . $d0;
 727                         } else {
 728                                 $r0 = $d0;
 729                         }
 730                         // Do the output
 731                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 732                                 // Range
 733                                 if ( $ord2 > $ord0 ) {
 734                                         // Empty range
 735                                 } elseif ( $ord0 >= 0x80 ) {
 736                                         // Unicode range
 737                                         $allowUnicode = true;
 738                                         if ( $ord2 < 0x80 ) {
 739                                                 // Keep the non-unicode section of the range
 740                                                 $out .= "$r2-\\x7F";
 741                                         }
 742                                 } else {
 743                                         // Normal range
 744                                         $out .= "$r2-$r0";
 745                                 }
 746                                 // Reset state to the initial value
 747                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 748                         } elseif ( $ord2 < 0x80 ) {
 749                                 // ASCII character
 750                                 $out .= $r2;
 751                         }
 752                 }
 753                 if ( $ord1 < 0x80 ) {
 754                         $out .= $r1;
 755                 }
 756                 if ( $ord0 < 0x80 ) {
 757                         $out .= $r0;
 758                 }
 759                 if ( $allowUnicode ) {
 760                         $out .= '\u0080-\uFFFF';
 761                 }
 762                 return $out;
 763         }
 764
 765         /**
 766          * Make a prefixed DB key from a DB key and a namespace index
 767          *
 768          * @param int $ns Numerical representation of the namespace
 769          * @param string $title The DB key form the title
 770          * @param string $fragment The link fragment (after the "#")
 771          * @param string $interwiki The interwiki prefix
 772          * @param bool $canoncialNamespace If true, use the canonical name for
 773          *   $ns instead of the localized version.
 774          * @return string The prefixed form of the title
 775          */
 776         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 777                 $canoncialNamespace = false
 778         ) {
 779                 global $wgContLang;
 780
 781                 if ( $canoncialNamespace ) {
 782                         $namespace = MWNamespace::getCanonicalName( $ns );
 783                 } else {
 784                         $namespace = $wgContLang->getNsText( $ns );
 785                 }
 786                 $name = $namespace == '' ? $title : "$namespace:$title";
 787                 if ( strval( $interwiki ) != '' ) {
 788                         $name = "$interwiki:$name";
 789                 }
 790                 if ( strval( $fragment ) != '' ) {
 791                         $name .= '#' . $fragment;
 792                 }
 793                 return $name;
 794         }
 795
 796         /**
 797          * Escape a text fragment, say from a link, for a URL
 798          *
 799          * @param string $fragment Containing a URL or link fragment (after the "#")
 800          * @return string Escaped string
 801          */
 802         static function escapeFragmentForURL( $fragment ) {
 803                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 804                 # fragments appear not to work in IE (at least up to 7) or in at least
 805                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 806                 # to care if they aren't encoded.
 807                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 808         }
 809
 810         /**
 811          * Callback for usort() to do title sorts by (namespace, title)
 812          *
 813          * @param Title $a
 814          * @param Title $b
 815          *
 816          * @return int Result of string comparison, or namespace comparison
 817          */
 818         public static function compare( $a, $b ) {
 819                 if ( $a->getNamespace() == $b->getNamespace() ) {
 820                         return strcmp( $a->getText(), $b->getText() );
 821                 } else {
 822                         return $a->getNamespace() - $b->getNamespace();
 823                 }
 824         }
 825
 826         /**
 827          * Determine whether the object refers to a page within
 828          * this project (either this wiki or a wiki with a local
 829          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 830          *
 831          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 832          */
 833         public function isLocal() {
 834                 if ( $this->isExternal() ) {
 835                         $iw = Interwiki::fetch( $this->mInterwiki );
 836                         if ( $iw ) {
 837                                 return $iw->isLocal();
 838                         }
 839                 }
 840                 return true;
 841         }
 842
 843         /**
 844          * Is this Title interwiki?
 845          *
 846          * @return bool
 847          */
 848         public function isExternal() {
 849                 return $this->mInterwiki !== '';
 850         }
 851
 852         /**
 853          * Get the interwiki prefix
 854          *
 855          * Use Title::isExternal to check if a interwiki is set
 856          *
 857          * @return string Interwiki prefix
 858          */
 859         public function getInterwiki() {
 860                 return $this->mInterwiki;
 861         }
 862
 863         /**
 864          * Was this a local interwiki link?
 865          *
 866          * @return bool
 867          */
 868         public function wasLocalInterwiki() {
 869                 return $this->mLocalInterwiki;
 870         }
 871
 872         /**
 873          * Determine whether the object refers to a page within
 874          * this project and is transcludable.
 875          *
 876          * @return bool True if this is transcludable
 877          */
 878         public function isTrans() {
 879                 if ( !$this->isExternal() ) {
 880                         return false;
 881                 }
 882
 883                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 884         }
 885
 886         /**
 887          * Returns the DB name of the distant wiki which owns the object.
 888          *
 889          * @return string The DB name
 890          */
 891         public function getTransWikiID() {
 892                 if ( !$this->isExternal() ) {
 893                         return false;
 894                 }
 895
 896                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 897         }
 898
 899         /**
 900          * Get a TitleValue object representing this Title.
 901          *
 902          * @note Not all valid Titles have a corresponding valid TitleValue
 903          * (e.g. TitleValues cannot represent page-local links that have a
 904          * fragment but no title text).
 905          *
 906          * @return TitleValue|null
 907          */
 908         public function getTitleValue() {
 909                 if ( $this->mTitleValue === null ) {
 910                         try {
 911                                 $this->mTitleValue = new TitleValue(
 912                                         $this->getNamespace(),
 913                                         $this->getDBkey(),
 914                                         $this->getFragment() );
 915                         } catch ( InvalidArgumentException $ex ) {
 916                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 917                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 918                         }
 919                 }
 920
 921                 return $this->mTitleValue;
 922         }
 923
 924         /**
 925          * Get the text form (spaces not underscores) of the main part
 926          *
 927          * @return string Main part of the title
 928          */
 929         public function getText() {
 930                 return $this->mTextform;
 931         }
 932
 933         /**
 934          * Get the URL-encoded form of the main part
 935          *
 936          * @return string Main part of the title, URL-encoded
 937          */
 938         public function getPartialURL() {
 939                 return $this->mUrlform;
 940         }
 941
 942         /**
 943          * Get the main part with underscores
 944          *
 945          * @return string Main part of the title, with underscores
 946          */
 947         public function getDBkey() {
 948                 return $this->mDbkeyform;
 949         }
 950
 951         /**
 952          * Get the DB key with the initial letter case as specified by the user
 953          *
 954          * @return string DB key
 955          */
 956         function getUserCaseDBKey() {
 957                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 958                         return $this->mUserCaseDBKey;
 959                 } else {
 960                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 961                         return $this->mDbkeyform;
 962                 }
 963         }
 964
 965         /**
 966          * Get the namespace index, i.e. one of the NS_xxxx constants.
 967          *
 968          * @return int Namespace index
 969          */
 970         public function getNamespace() {
 971                 return $this->mNamespace;
 972         }
 973
 974         /**
 975          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 976          *
 977          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 978          * @return string Content model id
 979          */
 980         public function getContentModel( $flags = 0 ) {
 981                 if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 982                         $linkCache = LinkCache::singleton();
 983                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 984                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 985                 }
 986
 987                 if ( !$this->mContentModel ) {
 988                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 989                 }
 990
 991                 return $this->mContentModel;
 992         }
 993
 994         /**
 995          * Convenience method for checking a title's content model name
 996          *
 997          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 998          * @return bool True if $this->getContentModel() == $id
 999          */
1000         public function hasContentModel( $id ) {
1001                 return $this->getContentModel() == $id;
1002         }
1003
1004         /**
1005          * Get the namespace text
1006          *
1007          * @return string Namespace text
1008          */
1009         public function getNsText() {
1010                 if ( $this->isExternal() ) {
1011                         // This probably shouldn't even happen,
1012                         // but for interwiki transclusion it sometimes does.
1013                         // Use the canonical namespaces if possible to try to
1014                         // resolve a foreign namespace.
1015                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1016                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1017                         }
1018                 }
1019
1020                 try {
1021                         $formatter = self::getTitleFormatter();
1022                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1023                 } catch ( InvalidArgumentException $ex ) {
1024                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1025                         return false;
1026                 }
1027         }
1028
1029         /**
1030          * Get the namespace text of the subject (rather than talk) page
1031          *
1032          * @return string Namespace text
1033          */
1034         public function getSubjectNsText() {
1035                 global $wgContLang;
1036                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1037         }
1038
1039         /**
1040          * Get the namespace text of the talk page
1041          *
1042          * @return string Namespace text
1043          */
1044         public function getTalkNsText() {
1045                 global $wgContLang;
1046                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1047         }
1048
1049         /**
1050          * Could this title have a corresponding talk page?
1051          *
1052          * @return bool
1053          */
1054         public function canTalk() {
1055                 return MWNamespace::canTalk( $this->mNamespace );
1056         }
1057
1058         /**
1059          * Is this in a namespace that allows actual pages?
1060          *
1061          * @return bool
1062          */
1063         public function canExist() {
1064                 return $this->mNamespace >= NS_MAIN;
1065         }
1066
1067         /**
1068          * Can this title be added to a user's watchlist?
1069          *
1070          * @return bool
1071          */
1072         public function isWatchable() {
1073                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1074         }
1075
1076         /**
1077          * Returns true if this is a special page.
1078          *
1079          * @return bool
1080          */
1081         public function isSpecialPage() {
1082                 return $this->getNamespace() == NS_SPECIAL;
1083         }
1084
1085         /**
1086          * Returns true if this title resolves to the named special page
1087          *
1088          * @param string $name The special page name
1089          * @return bool
1090          */
1091         public function isSpecial( $name ) {
1092                 if ( $this->isSpecialPage() ) {
1093                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1094                         if ( $name == $thisName ) {
1095                                 return true;
1096                         }
1097                 }
1098                 return false;
1099         }
1100
1101         /**
1102          * If the Title refers to a special page alias which is not the local default, resolve
1103          * the alias, and localise the name as necessary.  Otherwise, return $this
1104          *
1105          * @return Title
1106          */
1107         public function fixSpecialName() {
1108                 if ( $this->isSpecialPage() ) {
1109                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1110                         if ( $canonicalName ) {
1111                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1112                                 if ( $localName != $this->mDbkeyform ) {
1113                                         return Title::makeTitle( NS_SPECIAL, $localName );
1114                                 }
1115                         }
1116                 }
1117                 return $this;
1118         }
1119
1120         /**
1121          * Returns true if the title is inside the specified namespace.
1122          *
1123          * Please make use of this instead of comparing to getNamespace()
1124          * This function is much more resistant to changes we may make
1125          * to namespaces than code that makes direct comparisons.
1126          * @param int $ns The namespace
1127          * @return bool
1128          * @since 1.19
1129          */
1130         public function inNamespace( $ns ) {
1131                 return MWNamespace::equals( $this->getNamespace(), $ns );
1132         }
1133
1134         /**
1135          * Returns true if the title is inside one of the specified namespaces.
1136          *
1137          * @param int $namespaces,... The namespaces to check for
1138          * @return bool
1139          * @since 1.19
1140          */
1141         public function inNamespaces( /* ... */ ) {
1142                 $namespaces = func_get_args();
1143                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1144                         $namespaces = $namespaces[0];
1145                 }
1146
1147                 foreach ( $namespaces as $ns ) {
1148                         if ( $this->inNamespace( $ns ) ) {
1149                                 return true;
1150                         }
1151                 }
1152
1153                 return false;
1154         }
1155
1156         /**
1157          * Returns true if the title has the same subject namespace as the
1158          * namespace specified.
1159          * For example this method will take NS_USER and return true if namespace
1160          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1161          * as their subject namespace.
1162          *
1163          * This is MUCH simpler than individually testing for equivalence
1164          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1165          * @since 1.19
1166          * @param int $ns
1167          * @return bool
1168          */
1169         public function hasSubjectNamespace( $ns ) {
1170                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1171         }
1172
1173         /**
1174          * Is this Title in a namespace which contains content?
1175          * In other words, is this a content page, for the purposes of calculating
1176          * statistics, etc?
1177          *
1178          * @return bool
1179          */
1180         public function isContentPage() {
1181                 return MWNamespace::isContent( $this->getNamespace() );
1182         }
1183
1184         /**
1185          * Would anybody with sufficient privileges be able to move this page?
1186          * Some pages just aren't movable.
1187          *
1188          * @return bool
1189          */
1190         public function isMovable() {
1191                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1192                         // Interwiki title or immovable namespace. Hooks don't get to override here
1193                         return false;
1194                 }
1195
1196                 $result = true;
1197                 Hooks::run( 'TitleIsMovable', array( $this, &$result ) );
1198                 return $result;
1199         }
1200
1201         /**
1202          * Is this the mainpage?
1203          * @note Title::newFromText seems to be sufficiently optimized by the title
1204          * cache that we don't need to over-optimize by doing direct comparisons and
1205          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1206          * ends up reporting something differently than $title->isMainPage();
1207          *
1208          * @since 1.18
1209          * @return bool
1210          */
1211         public function isMainPage() {
1212                 return $this->equals( Title::newMainPage() );
1213         }
1214
1215         /**
1216          * Is this a subpage?
1217          *
1218          * @return bool
1219          */
1220         public function isSubpage() {
1221                 return MWNamespace::hasSubpages( $this->mNamespace )
1222                         ? strpos( $this->getText(), '/' ) !== false
1223                         : false;
1224         }
1225
1226         /**
1227          * Is this a conversion table for the LanguageConverter?
1228          *
1229          * @return bool
1230          */
1231         public function isConversionTable() {
1232                 // @todo ConversionTable should become a separate content model.
1233
1234                 return $this->getNamespace() == NS_MEDIAWIKI &&
1235                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1236         }
1237
1238         /**
1239          * Does that page contain wikitext, or it is JS, CSS or whatever?
1240          *
1241          * @return bool
1242          */
1243         public function isWikitextPage() {
1244                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1245         }
1246
1247         /**
1248          * Could this page contain custom CSS or JavaScript for the global UI.
1249          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1250          * or CONTENT_MODEL_JAVASCRIPT.
1251          *
1252          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1253          * for that!
1254          *
1255          * Note that this method should not return true for pages that contain and
1256          * show "inactive" CSS or JS.
1257          *
1258          * @return bool
1259          */
1260         public function isCssOrJsPage() {
1261                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1262                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1263                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1264
1265                 # @note This hook is also called in ContentHandler::getDefaultModel.
1266                 #   It's called here again to make sure hook functions can force this
1267                 #   method to return true even outside the MediaWiki namespace.
1268
1269                 Hooks::run( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ), '1.25' );
1270
1271                 return $isCssOrJsPage;
1272         }
1273
1274         /**
1275          * Is this a .css or .js subpage of a user page?
1276          * @return bool
1277          */
1278         public function isCssJsSubpage() {
1279                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1280                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1281                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1282         }
1283
1284         /**
1285          * Trim down a .css or .js subpage title to get the corresponding skin name
1286          *
1287          * @return string Containing skin name from .css or .js subpage title
1288          */
1289         public function getSkinFromCssJsSubpage() {
1290                 $subpage = explode( '/', $this->mTextform );
1291                 $subpage = $subpage[count( $subpage ) - 1];
1292                 $lastdot = strrpos( $subpage, '.' );
1293                 if ( $lastdot === false ) {
1294                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1295                 }
1296                 return substr( $subpage, 0, $lastdot );
1297         }
1298
1299         /**
1300          * Is this a .css subpage of a user page?
1301          *
1302          * @return bool
1303          */
1304         public function isCssSubpage() {
1305                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1306                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1307         }
1308
1309         /**
1310          * Is this a .js subpage of a user page?
1311          *
1312          * @return bool
1313          */
1314         public function isJsSubpage() {
1315                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1316                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1317         }
1318
1319         /**
1320          * Is this a talk page of some sort?
1321          *
1322          * @return bool
1323          */
1324         public function isTalkPage() {
1325                 return MWNamespace::isTalk( $this->getNamespace() );
1326         }
1327
1328         /**
1329          * Get a Title object associated with the talk page of this article
1330          *
1331          * @return Title The object for the talk page
1332          */
1333         public function getTalkPage() {
1334                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1335         }
1336
1337         /**
1338          * Get a title object associated with the subject page of this
1339          * talk page
1340          *
1341          * @return Title The object for the subject page
1342          */
1343         public function getSubjectPage() {
1344                 // Is this the same title?
1345                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1346                 if ( $this->getNamespace() == $subjectNS ) {
1347                         return $this;
1348                 }
1349                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1350         }
1351
1352         /**
1353          * Get the other title for this page, if this is a subject page
1354          * get the talk page, if it is a subject page get the talk page
1355          *
1356          * @since 1.25
1357          * @throws MWException
1358          * @return Title
1359          */
1360         public function getOtherPage() {
1361                 if ( $this->isSpecialPage() ) {
1362                         throw new MWException( 'Special pages cannot have other pages' );
1363                 }
1364                 if ( $this->isTalkPage() ) {
1365                         return $this->getSubjectPage();
1366                 } else {
1367                         return $this->getTalkPage();
1368                 }
1369         }
1370
1371         /**
1372          * Get the default namespace index, for when there is no namespace
1373          *
1374          * @return int Default namespace index
1375          */
1376         public function getDefaultNamespace() {
1377                 return $this->mDefaultNamespace;
1378         }
1379
1380         /**
1381          * Get the Title fragment (i.e.\ the bit after the #) in text form
1382          *
1383          * Use Title::hasFragment to check for a fragment
1384          *
1385          * @return string Title fragment
1386          */
1387         public function getFragment() {
1388                 return $this->mFragment;
1389         }
1390
1391         /**
1392          * Check if a Title fragment is set
1393          *
1394          * @return bool
1395          * @since 1.23
1396          */
1397         public function hasFragment() {
1398                 return $this->mFragment !== '';
1399         }
1400
1401         /**
1402          * Get the fragment in URL form, including the "#" character if there is one
1403          * @return string Fragment in URL form
1404          */
1405         public function getFragmentForURL() {
1406                 if ( !$this->hasFragment() ) {
1407                         return '';
1408                 } else {
1409                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1410                 }
1411         }
1412
1413         /**
1414          * Set the fragment for this title. Removes the first character from the
1415          * specified fragment before setting, so it assumes you're passing it with
1416          * an initial "#".
1417          *
1418          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1419          * Still in active use privately.
1420          *
1421          * @param string $fragment Text
1422          */
1423         public function setFragment( $fragment ) {
1424                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1425         }
1426
1427         /**
1428          * Prefix some arbitrary text with the namespace or interwiki prefix
1429          * of this object
1430          *
1431          * @param string $name The text
1432          * @return string The prefixed text
1433          */
1434         private function prefix( $name ) {
1435                 $p = '';
1436                 if ( $this->isExternal() ) {
1437                         $p = $this->mInterwiki . ':';
1438                 }
1439
1440                 if ( 0 != $this->mNamespace ) {
1441                         $p .= $this->getNsText() . ':';
1442                 }
1443                 return $p . $name;
1444         }
1445
1446         /**
1447          * Get the prefixed database key form
1448          *
1449          * @return string The prefixed title, with underscores and
1450          *  any interwiki and namespace prefixes
1451          */
1452         public function getPrefixedDBkey() {
1453                 $s = $this->prefix( $this->mDbkeyform );
1454                 $s = strtr( $s, ' ', '_' );
1455                 return $s;
1456         }
1457
1458         /**
1459          * Get the prefixed title with spaces.
1460          * This is the form usually used for display
1461          *
1462          * @return string The prefixed title, with spaces
1463          */
1464         public function getPrefixedText() {
1465                 if ( $this->mPrefixedText === null ) {
1466                         $s = $this->prefix( $this->mTextform );
1467                         $s = strtr( $s, '_', ' ' );
1468                         $this->mPrefixedText = $s;
1469                 }
1470                 return $this->mPrefixedText;
1471         }
1472
1473         /**
1474          * Return a string representation of this title
1475          *
1476          * @return string Representation of this title
1477          */
1478         public function __toString() {
1479                 return $this->getPrefixedText();
1480         }
1481
1482         /**
1483          * Get the prefixed title with spaces, plus any fragment
1484          * (part beginning with '#')
1485          *
1486          * @return string The prefixed title, with spaces and the fragment, including '#'
1487          */
1488         public function getFullText() {
1489                 $text = $this->getPrefixedText();
1490                 if ( $this->hasFragment() ) {
1491                         $text .= '#' . $this->getFragment();
1492                 }
1493                 return $text;
1494         }
1495
1496         /**
1497          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1498          *
1499          * @par Example:
1500          * @code
1501          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1502          * # returns: 'Foo'
1503          * @endcode
1504          *
1505          * @return string Root name
1506          * @since 1.20
1507          */
1508         public function getRootText() {
1509                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1510                         return $this->getText();
1511                 }
1512
1513                 return strtok( $this->getText(), '/' );
1514         }
1515
1516         /**
1517          * Get the root page name title, i.e. the leftmost part before any slashes
1518          *
1519          * @par Example:
1520          * @code
1521          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1522          * # returns: Title{User:Foo}
1523          * @endcode
1524          *
1525          * @return Title Root title
1526          * @since 1.20
1527          */
1528         public function getRootTitle() {
1529                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1530         }
1531
1532         /**
1533          * Get the base page name without a namespace, i.e. the part before the subpage name
1534          *
1535          * @par Example:
1536          * @code
1537          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1538          * # returns: 'Foo/Bar'
1539          * @endcode
1540          *
1541          * @return string Base name
1542          */
1543         public function getBaseText() {
1544                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1545                         return $this->getText();
1546                 }
1547
1548                 $parts = explode( '/', $this->getText() );
1549                 # Don't discard the real title if there's no subpage involved
1550                 if ( count( $parts ) > 1 ) {
1551                         unset( $parts[count( $parts ) - 1] );
1552                 }
1553                 return implode( '/', $parts );
1554         }
1555
1556         /**
1557          * Get the base page name title, i.e. the part before the subpage name
1558          *
1559          * @par Example:
1560          * @code
1561          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1562          * # returns: Title{User:Foo/Bar}
1563          * @endcode
1564          *
1565          * @return Title Base title
1566          * @since 1.20
1567          */
1568         public function getBaseTitle() {
1569                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1570         }
1571
1572         /**
1573          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1574          *
1575          * @par Example:
1576          * @code
1577          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1578          * # returns: "Baz"
1579          * @endcode
1580          *
1581          * @return string Subpage name
1582          */
1583         public function getSubpageText() {
1584                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1585                         return $this->mTextform;
1586                 }
1587                 $parts = explode( '/', $this->mTextform );
1588                 return $parts[count( $parts ) - 1];
1589         }
1590
1591         /**
1592          * Get the title for a subpage of the current page
1593          *
1594          * @par Example:
1595          * @code
1596          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1597          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1598          * @endcode
1599          *
1600          * @param string $text The subpage name to add to the title
1601          * @return Title Subpage title
1602          * @since 1.20
1603          */
1604         public function getSubpage( $text ) {
1605                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1606         }
1607
1608         /**
1609          * Get a URL-encoded form of the subpage text
1610          *
1611          * @return string URL-encoded subpage name
1612          */
1613         public function getSubpageUrlForm() {
1614                 $text = $this->getSubpageText();
1615                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1616                 return $text;
1617         }
1618
1619         /**
1620          * Get a URL-encoded title (not an actual URL) including interwiki
1621          *
1622          * @return string The URL-encoded form
1623          */
1624         public function getPrefixedURL() {
1625                 $s = $this->prefix( $this->mDbkeyform );
1626                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1627                 return $s;
1628         }
1629
1630         /**
1631          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1632          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1633          * second argument named variant. This was deprecated in favor
1634          * of passing an array of option with a "variant" key
1635          * Once $query2 is removed for good, this helper can be dropped
1636          * and the wfArrayToCgi moved to getLocalURL();
1637          *
1638          * @since 1.19 (r105919)
1639          * @param array|string $query
1640          * @param bool $query2
1641          * @return string
1642          */
1643         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1644                 if ( $query2 !== false ) {
1645                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1646                                 "method called with a second parameter is deprecated. Add your " .
1647                                 "parameter to an array passed as the first parameter.", "1.19" );
1648                 }
1649                 if ( is_array( $query ) ) {
1650                         $query = wfArrayToCgi( $query );
1651                 }
1652                 if ( $query2 ) {
1653                         if ( is_string( $query2 ) ) {
1654                                 // $query2 is a string, we will consider this to be
1655                                 // a deprecated $variant argument and add it to the query
1656                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1657                         } else {
1658                                 $query2 = wfArrayToCgi( $query2 );
1659                         }
1660                         // If we have $query content add a & to it first
1661                         if ( $query ) {
1662                                 $query .= '&';
1663                         }
1664                         // Now append the queries together
1665                         $query .= $query2;
1666                 }
1667                 return $query;
1668         }
1669
1670         /**
1671          * Get a real URL referring to this title, with interwiki link and
1672          * fragment
1673          *
1674          * @see self::getLocalURL for the arguments.
1675          * @see wfExpandUrl
1676          * @param array|string $query
1677          * @param bool $query2
1678          * @param string $proto Protocol type to use in URL
1679          * @return string The URL
1680          */
1681         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1682                 $query = self::fixUrlQueryArgs( $query, $query2 );
1683
1684                 # Hand off all the decisions on urls to getLocalURL
1685                 $url = $this->getLocalURL( $query );
1686
1687                 # Expand the url to make it a full url. Note that getLocalURL has the
1688                 # potential to output full urls for a variety of reasons, so we use
1689                 # wfExpandUrl instead of simply prepending $wgServer
1690                 $url = wfExpandUrl( $url, $proto );
1691
1692                 # Finally, add the fragment.
1693                 $url .= $this->getFragmentForURL();
1694
1695                 Hooks::run( 'GetFullURL', array( &$this, &$url, $query ) );
1696                 return $url;
1697         }
1698
1699         /**
1700          * Get a URL with no fragment or server name (relative URL) from a Title object.
1701          * If this page is generated with action=render, however,
1702          * $wgServer is prepended to make an absolute URL.
1703          *
1704          * @see self::getFullURL to always get an absolute URL.
1705          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1706          *  valid to link, locally, to the current Title.
1707          * @see self::newFromText to produce a Title object.
1708          *
1709          * @param string|array $query An optional query string,
1710          *   not used for interwiki links. Can be specified as an associative array as well,
1711          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1712          *   Some query patterns will trigger various shorturl path replacements.
1713          * @param array $query2 An optional secondary query array. This one MUST
1714          *   be an array. If a string is passed it will be interpreted as a deprecated
1715          *   variant argument and urlencoded into a variant= argument.
1716          *   This second query argument will be added to the $query
1717          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1718          *   pair in the first parameter array instead.
1719          *
1720          * @return string String of the URL.
1721          */
1722         public function getLocalURL( $query = '', $query2 = false ) {
1723                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1724
1725                 $query = self::fixUrlQueryArgs( $query, $query2 );
1726
1727                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1728                 if ( $interwiki ) {
1729                         $namespace = $this->getNsText();
1730                         if ( $namespace != '' ) {
1731                                 # Can this actually happen? Interwikis shouldn't be parsed.
1732                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1733                                 $namespace .= ':';
1734                         }
1735                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1736                         $url = wfAppendQuery( $url, $query );
1737                 } else {
1738                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1739                         if ( $query == '' ) {
1740                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1741                                 Hooks::run( 'GetLocalURL::Article', array( &$this, &$url ) );
1742                         } else {
1743                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1744                                 $url = false;
1745                                 $matches = array();
1746
1747                                 if ( !empty( $wgActionPaths )
1748                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1749                                 ) {
1750                                         $action = urldecode( $matches[2] );
1751                                         if ( isset( $wgActionPaths[$action] ) ) {
1752                                                 $query = $matches[1];
1753                                                 if ( isset( $matches[4] ) ) {
1754                                                         $query .= $matches[4];
1755                                                 }
1756                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1757                                                 if ( $query != '' ) {
1758                                                         $url = wfAppendQuery( $url, $query );
1759                                                 }
1760                                         }
1761                                 }
1762
1763                                 if ( $url === false
1764                                         && $wgVariantArticlePath
1765                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1766                                         && $this->getPageLanguage()->hasVariants()
1767                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1768                                 ) {
1769                                         $variant = urldecode( $matches[1] );
1770                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1771                                                 // Only do the variant replacement if the given variant is a valid
1772                                                 // variant for the page's language.
1773                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1774                                                 $url = str_replace( '$1', $dbkey, $url );
1775                                         }
1776                                 }
1777
1778                                 if ( $url === false ) {
1779                                         if ( $query == '-' ) {
1780                                                 $query = '';
1781                                         }
1782                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1783                                 }
1784                         }
1785
1786                         Hooks::run( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1787
1788                         // @todo FIXME: This causes breakage in various places when we
1789                         // actually expected a local URL and end up with dupe prefixes.
1790                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1791                                 $url = $wgServer . $url;
1792                         }
1793                 }
1794                 Hooks::run( 'GetLocalURL', array( &$this, &$url, $query ) );
1795                 return $url;
1796         }
1797
1798         /**
1799          * Get a URL that's the simplest URL that will be valid to link, locally,
1800          * to the current Title.  It includes the fragment, but does not include
1801          * the server unless action=render is used (or the link is external).  If
1802          * there's a fragment but the prefixed text is empty, we just return a link
1803          * to the fragment.
1804          *
1805          * The result obviously should not be URL-escaped, but does need to be
1806          * HTML-escaped if it's being output in HTML.
1807          *
1808          * @param array $query
1809          * @param bool $query2
1810          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1811          * @see self::getLocalURL for the arguments.
1812          * @return string The URL
1813          */
1814         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1815                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1816                         $ret = $this->getFullURL( $query, $query2, $proto );
1817                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1818                         $ret = $this->getFragmentForURL();
1819                 } else {
1820                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1821                 }
1822                 return $ret;
1823         }
1824
1825         /**
1826          * Get the URL form for an internal link.
1827          * - Used in various Squid-related code, in case we have a different
1828          * internal hostname for the server from the exposed one.
1829          *
1830          * This uses $wgInternalServer to qualify the path, or $wgServer
1831          * if $wgInternalServer is not set. If the server variable used is
1832          * protocol-relative, the URL will be expanded to http://
1833          *
1834          * @see self::getLocalURL for the arguments.
1835          * @return string The URL
1836          */
1837         public function getInternalURL( $query = '', $query2 = false ) {
1838                 global $wgInternalServer, $wgServer;
1839                 $query = self::fixUrlQueryArgs( $query, $query2 );
1840                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1841                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1842                 Hooks::run( 'GetInternalURL', array( &$this, &$url, $query ) );
1843                 return $url;
1844         }
1845
1846         /**
1847          * Get the URL for a canonical link, for use in things like IRC and
1848          * e-mail notifications. Uses $wgCanonicalServer and the
1849          * GetCanonicalURL hook.
1850          *
1851          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1852          *
1853          * @see self::getLocalURL for the arguments.
1854          * @return string The URL
1855          * @since 1.18
1856          */
1857         public function getCanonicalURL( $query = '', $query2 = false ) {
1858                 $query = self::fixUrlQueryArgs( $query, $query2 );
1859                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1860                 Hooks::run( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1861                 return $url;
1862         }
1863
1864         /**
1865          * Get the edit URL for this Title
1866          *
1867          * @return string The URL, or a null string if this is an interwiki link
1868          */
1869         public function getEditURL() {
1870                 if ( $this->isExternal() ) {
1871                         return '';
1872                 }
1873                 $s = $this->getLocalURL( 'action=edit' );
1874
1875                 return $s;
1876         }
1877
1878         /**
1879          * Is $wgUser watching this page?
1880          *
1881          * @deprecated since 1.20; use User::isWatched() instead.
1882          * @return bool
1883          */
1884         public function userIsWatching() {
1885                 global $wgUser;
1886
1887                 if ( is_null( $this->mWatched ) ) {
1888                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1889                                 $this->mWatched = false;
1890                         } else {
1891                                 $this->mWatched = $wgUser->isWatched( $this );
1892                         }
1893                 }
1894                 return $this->mWatched;
1895         }
1896
1897         /**
1898          * Can $user perform $action on this page?
1899          * This skips potentially expensive cascading permission checks
1900          * as well as avoids expensive error formatting
1901          *
1902          * Suitable for use for nonessential UI controls in common cases, but
1903          * _not_ for functional access control.
1904          *
1905          * May provide false positives, but should never provide a false negative.
1906          *
1907          * @param string $action Action that permission needs to be checked for
1908          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1909          * @return bool
1910          */
1911         public function quickUserCan( $action, $user = null ) {
1912                 return $this->userCan( $action, $user, false );
1913         }
1914
1915         /**
1916          * Can $user perform $action on this page?
1917          *
1918          * @param string $action Action that permission needs to be checked for
1919          * @param User $user User to check (since 1.19); $wgUser will be used if not
1920          *   provided.
1921          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1922          * @return bool
1923          */
1924         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1925                 if ( !$user instanceof User ) {
1926                         global $wgUser;
1927                         $user = $wgUser;
1928                 }
1929
1930                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1931         }
1932
1933         /**
1934          * Can $user perform $action on this page?
1935          *
1936          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1937          *
1938          * @param string $action Action that permission needs to be checked for
1939          * @param User $user User to check
1940          * @param string $rigor One of (quick,full,secure)
1941          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
1942          *   - full   : does cheap and expensive checks possibly from a slave
1943          *   - secure : does cheap and expensive checks, using the master as needed
1944          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1945          *   whose corresponding errors may be ignored.
1946          * @return array Array of arguments to wfMessage to explain permissions problems.
1947          */
1948         public function getUserPermissionsErrors(
1949                 $action, $user, $rigor = 'secure', $ignoreErrors = array()
1950         ) {
1951                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1952
1953                 // Remove the errors being ignored.
1954                 foreach ( $errors as $index => $error ) {
1955                         $error_key = is_array( $error ) ? $error[0] : $error;
1956
1957                         if ( in_array( $error_key, $ignoreErrors ) ) {
1958                                 unset( $errors[$index] );
1959                         }
1960                 }
1961
1962                 return $errors;
1963         }
1964
1965         /**
1966          * Permissions checks that fail most often, and which are easiest to test.
1967          *
1968          * @param string $action The action to check
1969          * @param User $user User to check
1970          * @param array $errors List of current errors
1971          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1972          * @param bool $short Short circuit on first error
1973          *
1974          * @return array List of errors
1975          */
1976         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1977                 if ( !Hooks::run( 'TitleQuickPermissions',
1978                         array( $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ) )
1979                 ) {
1980                         return $errors;
1981                 }
1982
1983                 if ( $action == 'create' ) {
1984                         if (
1985                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1986                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1987                         ) {
1988                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1989                         }
1990                 } elseif ( $action == 'move' ) {
1991                         if ( !$user->isAllowed( 'move-rootuserpages' )
1992                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1993                                 // Show user page-specific message only if the user can move other pages
1994                                 $errors[] = array( 'cant-move-user-page' );
1995                         }
1996
1997                         // Check if user is allowed to move files if it's a file
1998                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1999                                 $errors[] = array( 'movenotallowedfile' );
2000                         }
2001
2002                         // Check if user is allowed to move category pages if it's a category page
2003                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2004                                 $errors[] = array( 'cant-move-category-page' );
2005                         }
2006
2007                         if ( !$user->isAllowed( 'move' ) ) {
2008                                 // User can't move anything
2009                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2010                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2011                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2012                                         // custom message if logged-in users without any special rights can move
2013                                         $errors[] = array( 'movenologintext' );
2014                                 } else {
2015                                         $errors[] = array( 'movenotallowed' );
2016                                 }
2017                         }
2018                 } elseif ( $action == 'move-target' ) {
2019                         if ( !$user->isAllowed( 'move' ) ) {
2020                                 // User can't move anything
2021                                 $errors[] = array( 'movenotallowed' );
2022                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2023                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2024                                 // Show user page-specific message only if the user can move other pages
2025                                 $errors[] = array( 'cant-move-to-user-page' );
2026                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2027                                         && $this->mNamespace == NS_CATEGORY ) {
2028                                 // Show category page-specific message only if the user can move other pages
2029                                 $errors[] = array( 'cant-move-to-category-page' );
2030                         }
2031                 } elseif ( !$user->isAllowed( $action ) ) {
2032                         $errors[] = $this->missingPermissionError( $action, $short );
2033                 }
2034
2035                 return $errors;
2036         }
2037
2038         /**
2039          * Add the resulting error code to the errors array
2040          *
2041          * @param array $errors List of current errors
2042          * @param array $result Result of errors
2043          *
2044          * @return array List of errors
2045          */
2046         private function resultToError( $errors, $result ) {
2047                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2048                         // A single array representing an error
2049                         $errors[] = $result;
2050                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2051                         // A nested array representing multiple errors
2052                         $errors = array_merge( $errors, $result );
2053                 } elseif ( $result !== '' && is_string( $result ) ) {
2054                         // A string representing a message-id
2055                         $errors[] = array( $result );
2056                 } elseif ( $result === false ) {
2057                         // a generic "We don't want them to do that"
2058                         $errors[] = array( 'badaccess-group0' );
2059                 }
2060                 return $errors;
2061         }
2062
2063         /**
2064          * Check various permission hooks
2065          *
2066          * @param string $action The action to check
2067          * @param User $user User to check
2068          * @param array $errors List of current errors
2069          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2070          * @param bool $short Short circuit on first error
2071          *
2072          * @return array List of errors
2073          */
2074         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2075                 // Use getUserPermissionsErrors instead
2076                 $result = '';
2077                 if ( !Hooks::run( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2078                         return $result ? array() : array( array( 'badaccess-group0' ) );
2079                 }
2080                 // Check getUserPermissionsErrors hook
2081                 if ( !Hooks::run( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2082                         $errors = $this->resultToError( $errors, $result );
2083                 }
2084                 // Check getUserPermissionsErrorsExpensive hook
2085                 if (
2086                         $rigor !== 'quick'
2087                         && !( $short && count( $errors ) > 0 )
2088                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2089                 ) {
2090                         $errors = $this->resultToError( $errors, $result );
2091                 }
2092
2093                 return $errors;
2094         }
2095
2096         /**
2097          * Check permissions on special pages & namespaces
2098          *
2099          * @param string $action The action to check
2100          * @param User $user User to check
2101          * @param array $errors List of current errors
2102          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2103          * @param bool $short Short circuit on first error
2104          *
2105          * @return array List of errors
2106          */
2107         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2108                 # Only 'createaccount' can be performed on special pages,
2109                 # which don't actually exist in the DB.
2110                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2111                         $errors[] = array( 'ns-specialprotected' );
2112                 }
2113
2114                 # Check $wgNamespaceProtection for restricted namespaces
2115                 if ( $this->isNamespaceProtected( $user ) ) {
2116                         $ns = $this->mNamespace == NS_MAIN ?
2117                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2118                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2119                                 array( 'protectedinterface', $action ) : array( 'namespaceprotected', $ns, $action );
2120                 }
2121
2122                 return $errors;
2123         }
2124
2125         /**
2126          * Check CSS/JS sub-page permissions
2127          *
2128          * @param string $action The action to check
2129          * @param User $user User to check
2130          * @param array $errors List of current errors
2131          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2132          * @param bool $short Short circuit on first error
2133          *
2134          * @return array List of errors
2135          */
2136         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2137                 # Protect css/js subpages of user pages
2138                 # XXX: this might be better using restrictions
2139                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2140                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2141                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2142                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2143                                         $errors[] = array( 'mycustomcssprotected', $action );
2144                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2145                                         $errors[] = array( 'mycustomjsprotected', $action );
2146                                 }
2147                         } else {
2148                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2149                                         $errors[] = array( 'customcssprotected', $action );
2150                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2151                                         $errors[] = array( 'customjsprotected', $action );
2152                                 }
2153                         }
2154                 }
2155
2156                 return $errors;
2157         }
2158
2159         /**
2160          * Check against page_restrictions table requirements on this
2161          * page. The user must possess all required rights for this
2162          * action.
2163          *
2164          * @param string $action The action to check
2165          * @param User $user User to check
2166          * @param array $errors List of current errors
2167          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2168          * @param bool $short Short circuit on first error
2169          *
2170          * @return array List of errors
2171          */
2172         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2173                 foreach ( $this->getRestrictions( $action ) as $right ) {
2174                         // Backwards compatibility, rewrite sysop -> editprotected
2175                         if ( $right == 'sysop' ) {
2176                                 $right = 'editprotected';
2177                         }
2178                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2179                         if ( $right == 'autoconfirmed' ) {
2180                                 $right = 'editsemiprotected';
2181                         }
2182                         if ( $right == '' ) {
2183                                 continue;
2184                         }
2185                         if ( !$user->isAllowed( $right ) ) {
2186                                 $errors[] = array( 'protectedpagetext', $right, $action );
2187                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2188                                 $errors[] = array( 'protectedpagetext', 'protect', $action );
2189                         }
2190                 }
2191
2192                 return $errors;
2193         }
2194
2195         /**
2196          * Check restrictions on cascading pages.
2197          *
2198          * @param string $action The action to check
2199          * @param User $user User to check
2200          * @param array $errors List of current errors
2201          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2202          * @param bool $short Short circuit on first error
2203          *
2204          * @return array List of errors
2205          */
2206         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2207                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2208                         # We /could/ use the protection level on the source page, but it's
2209                         # fairly ugly as we have to establish a precedence hierarchy for pages
2210                         # included by multiple cascade-protected pages. So just restrict
2211                         # it to people with 'protect' permission, as they could remove the
2212                         # protection anyway.
2213                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2214                         # Cascading protection depends on more than this page...
2215                         # Several cascading protected pages may include this page...
2216                         # Check each cascading level
2217                         # This is only for protection restrictions, not for all actions
2218                         if ( isset( $restrictions[$action] ) ) {
2219                                 foreach ( $restrictions[$action] as $right ) {
2220                                         // Backwards compatibility, rewrite sysop -> editprotected
2221                                         if ( $right == 'sysop' ) {
2222                                                 $right = 'editprotected';
2223                                         }
2224                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2225                                         if ( $right == 'autoconfirmed' ) {
2226                                                 $right = 'editsemiprotected';
2227                                         }
2228                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2229                                                 $pages = '';
2230                                                 foreach ( $cascadingSources as $page ) {
2231                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2232                                                 }
2233                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages, $action );
2234                                         }
2235                                 }
2236                         }
2237                 }
2238
2239                 return $errors;
2240         }
2241
2242         /**
2243          * Check action permissions not already checked in checkQuickPermissions
2244          *
2245          * @param string $action The action to check
2246          * @param User $user User to check
2247          * @param array $errors List of current errors
2248          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2249          * @param bool $short Short circuit on first error
2250          *
2251          * @return array List of errors
2252          */
2253         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2254                 global $wgDeleteRevisionsLimit, $wgLang;
2255
2256                 if ( $action == 'protect' ) {
2257                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2258                                 // If they can't edit, they shouldn't protect.
2259                                 $errors[] = array( 'protect-cantedit' );
2260                         }
2261                 } elseif ( $action == 'create' ) {
2262                         $title_protection = $this->getTitleProtection();
2263                         if ( $title_protection ) {
2264                                 if ( $title_protection['permission'] == ''
2265                                         || !$user->isAllowed( $title_protection['permission'] )
2266                                 ) {
2267                                         $errors[] = array(
2268                                                 'titleprotected',
2269                                                 User::whoIs( $title_protection['user'] ),
2270                                                 $title_protection['reason']
2271                                         );
2272                                 }
2273                         }
2274                 } elseif ( $action == 'move' ) {
2275                         // Check for immobile pages
2276                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2277                                 // Specific message for this case
2278                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2279                         } elseif ( !$this->isMovable() ) {
2280                                 // Less specific message for rarer cases
2281                                 $errors[] = array( 'immobile-source-page' );
2282                         }
2283                 } elseif ( $action == 'move-target' ) {
2284                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2285                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2286                         } elseif ( !$this->isMovable() ) {
2287                                 $errors[] = array( 'immobile-target-page' );
2288                         }
2289                 } elseif ( $action == 'delete' ) {
2290                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, array(), $rigor, true );
2291                         if ( !$tempErrors ) {
2292                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2293                                         $user, $tempErrors, $rigor, true );
2294                         }
2295                         if ( $tempErrors ) {
2296                                 // If protection keeps them from editing, they shouldn't be able to delete.
2297                                 $errors[] = array( 'deleteprotected' );
2298                         }
2299                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2300                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2301                         ) {
2302                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2303                         }
2304                 }
2305                 return $errors;
2306         }
2307
2308         /**
2309          * Check that the user isn't blocked from editing.
2310          *
2311          * @param string $action The action to check
2312          * @param User $user User to check
2313          * @param array $errors List of current errors
2314          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2315          * @param bool $short Short circuit on first error
2316          *
2317          * @return array List of errors
2318          */
2319         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2320                 // Account creation blocks handled at userlogin.
2321                 // Unblocking handled in SpecialUnblock
2322                 if ( $rigor === 'quick' || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2323                         return $errors;
2324                 }
2325
2326                 global $wgEmailConfirmToEdit;
2327
2328                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2329                         $errors[] = array( 'confirmedittext' );
2330                 }
2331
2332                 $useSlave = ( $rigor !== 'secure' );
2333                 if ( ( $action == 'edit' || $action == 'create' )
2334                         && !$user->isBlockedFrom( $this, $useSlave )
2335                 ) {
2336                         // Don't block the user from editing their own talk page unless they've been
2337                         // explicitly blocked from that too.
2338                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2339                         // @todo FIXME: Pass the relevant context into this function.
2340                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2341                 }
2342
2343                 return $errors;
2344         }
2345
2346         /**
2347          * Check that the user is allowed to read this page.
2348          *
2349          * @param string $action The action to check
2350          * @param User $user User to check
2351          * @param array $errors List of current errors
2352          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2353          * @param bool $short Short circuit on first error
2354          *
2355          * @return array List of errors
2356          */
2357         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2358                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2359
2360                 $whitelisted = false;
2361                 if ( User::isEveryoneAllowed( 'read' ) ) {
2362                         # Shortcut for public wikis, allows skipping quite a bit of code
2363                         $whitelisted = true;
2364                 } elseif ( $user->isAllowed( 'read' ) ) {
2365                         # If the user is allowed to read pages, he is allowed to read all pages
2366                         $whitelisted = true;
2367                 } elseif ( $this->isSpecial( 'Userlogin' )
2368                         || $this->isSpecial( 'ChangePassword' )
2369                         || $this->isSpecial( 'PasswordReset' )
2370                 ) {
2371                         # Always grant access to the login page.
2372                         # Even anons need to be able to log in.
2373                         $whitelisted = true;
2374                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2375                         # Time to check the whitelist
2376                         # Only do these checks is there's something to check against
2377                         $name = $this->getPrefixedText();
2378                         $dbName = $this->getPrefixedDBkey();
2379
2380                         // Check for explicit whitelisting with and without underscores
2381                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2382                                 $whitelisted = true;
2383                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2384                                 # Old settings might have the title prefixed with
2385                                 # a colon for main-namespace pages
2386                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2387                                         $whitelisted = true;
2388                                 }
2389                         } elseif ( $this->isSpecialPage() ) {
2390                                 # If it's a special page, ditch the subpage bit and check again
2391                                 $name = $this->getDBkey();
2392                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2393                                 if ( $name ) {
2394                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2395                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2396                                                 $whitelisted = true;
2397                                         }
2398                                 }
2399                         }
2400                 }
2401
2402                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2403                         $name = $this->getPrefixedText();
2404                         // Check for regex whitelisting
2405                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2406                                 if ( preg_match( $listItem, $name ) ) {
2407                                         $whitelisted = true;
2408                                         break;
2409                                 }
2410                         }
2411                 }
2412
2413                 if ( !$whitelisted ) {
2414                         # If the title is not whitelisted, give extensions a chance to do so...
2415                         Hooks::run( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2416                         if ( !$whitelisted ) {
2417                                 $errors[] = $this->missingPermissionError( $action, $short );
2418                         }
2419                 }
2420
2421                 return $errors;
2422         }
2423
2424         /**
2425          * Get a description array when the user doesn't have the right to perform
2426          * $action (i.e. when User::isAllowed() returns false)
2427          *
2428          * @param string $action The action to check
2429          * @param bool $short Short circuit on first error
2430          * @return array List of errors
2431          */
2432         private function missingPermissionError( $action, $short ) {
2433                 // We avoid expensive display logic for quickUserCan's and such
2434                 if ( $short ) {
2435                         return array( 'badaccess-group0' );
2436                 }
2437
2438                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2439                         User::getGroupsWithPermission( $action ) );
2440
2441                 if ( count( $groups ) ) {
2442                         global $wgLang;
2443                         return array(
2444                                 'badaccess-groups',
2445                                 $wgLang->commaList( $groups ),
2446                                 count( $groups )
2447                         );
2448                 } else {
2449                         return array( 'badaccess-group0' );
2450                 }
2451         }
2452
2453         /**
2454          * Can $user perform $action on this page? This is an internal function,
2455          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2456          * checks on wfReadOnly() and blocks)
2457          *
2458          * @param string $action Action that permission needs to be checked for
2459          * @param User $user User to check
2460          * @param string $rigor One of (quick,full,secure)
2461          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
2462          *   - full   : does cheap and expensive checks possibly from a slave
2463          *   - secure : does cheap and expensive checks, using the master as needed
2464          * @param bool $short Set this to true to stop after the first permission error.
2465          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2466          */
2467         protected function getUserPermissionsErrorsInternal(
2468                 $action, $user, $rigor = 'secure', $short = false
2469         ) {
2470                 if ( $rigor === true ) {
2471                         $rigor = 'secure'; // b/c
2472                 } elseif ( $rigor === false ) {
2473                         $rigor = 'quick'; // b/c
2474                 } elseif ( !in_array( $rigor, array( 'quick', 'full', 'secure' ) ) ) {
2475                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2476                 }
2477
2478                 # Read has special handling
2479                 if ( $action == 'read' ) {
2480                         $checks = array(
2481                                 'checkPermissionHooks',
2482                                 'checkReadPermissions',
2483                         );
2484                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2485                 # here as it will lead to duplicate error messages. This is okay to do
2486                 # since anywhere that checks for create will also check for edit, and
2487                 # those checks are called for edit.
2488                 } elseif ( $action == 'create' ) {
2489                         $checks = array(
2490                                 'checkQuickPermissions',
2491                                 'checkPermissionHooks',
2492                                 'checkPageRestrictions',
2493                                 'checkCascadingSourcesRestrictions',
2494                                 'checkActionPermissions',
2495                                 'checkUserBlock'
2496                         );
2497                 } else {
2498                         $checks = array(
2499                                 'checkQuickPermissions',
2500                                 'checkPermissionHooks',
2501                                 'checkSpecialsAndNSPermissions',
2502                                 'checkCSSandJSPermissions',
2503                                 'checkPageRestrictions',
2504                                 'checkCascadingSourcesRestrictions',
2505                                 'checkActionPermissions',
2506                                 'checkUserBlock'
2507                         );
2508                 }
2509
2510                 $errors = array();
2511                 while ( count( $checks ) > 0 &&
2512                                 !( $short && count( $errors ) > 0 ) ) {
2513                         $method = array_shift( $checks );
2514                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2515                 }
2516
2517                 return $errors;
2518         }
2519
2520         /**
2521          * Get a filtered list of all restriction types supported by this wiki.
2522          * @param bool $exists True to get all restriction types that apply to
2523          * titles that do exist, False for all restriction types that apply to
2524          * titles that do not exist
2525          * @return array
2526          */
2527         public static function getFilteredRestrictionTypes( $exists = true ) {
2528                 global $wgRestrictionTypes;
2529                 $types = $wgRestrictionTypes;
2530                 if ( $exists ) {
2531                         # Remove the create restriction for existing titles
2532                         $types = array_diff( $types, array( 'create' ) );
2533                 } else {
2534                         # Only the create and upload restrictions apply to non-existing titles
2535                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2536                 }
2537                 return $types;
2538         }
2539
2540         /**
2541          * Returns restriction types for the current Title
2542          *
2543          * @return array Applicable restriction types
2544          */
2545         public function getRestrictionTypes() {
2546                 if ( $this->isSpecialPage() ) {
2547                         return array();
2548                 }
2549
2550                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2551
2552                 if ( $this->getNamespace() != NS_FILE ) {
2553                         # Remove the upload restriction for non-file titles
2554                         $types = array_diff( $types, array( 'upload' ) );
2555                 }
2556
2557                 Hooks::run( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2558
2559                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2560                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2561
2562                 return $types;
2563         }
2564
2565         /**
2566          * Is this title subject to title protection?
2567          * Title protection is the one applied against creation of such title.
2568          *
2569          * @return array|bool An associative array representing any existent title
2570          *   protection, or false if there's none.
2571          */
2572         public function getTitleProtection() {
2573                 // Can't protect pages in special namespaces
2574                 if ( $this->getNamespace() < 0 ) {
2575                         return false;
2576                 }
2577
2578                 // Can't protect pages that exist.
2579                 if ( $this->exists() ) {
2580                         return false;
2581                 }
2582
2583                 if ( $this->mTitleProtection === null ) {
2584                         $dbr = wfGetDB( DB_SLAVE );
2585                         $res = $dbr->select(
2586                                 'protected_titles',
2587                                 array(
2588                                         'user' => 'pt_user',
2589                                         'reason' => 'pt_reason',
2590                                         'expiry' => 'pt_expiry',
2591                                         'permission' => 'pt_create_perm'
2592                                 ),
2593                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2594                                 __METHOD__
2595                         );
2596
2597                         // fetchRow returns false if there are no rows.
2598                         $row = $dbr->fetchRow( $res );
2599                         if ( $row ) {
2600                                 if ( $row['permission'] == 'sysop' ) {
2601                                         $row['permission'] = 'editprotected'; // B/C
2602                                 }
2603                                 if ( $row['permission'] == 'autoconfirmed' ) {
2604                                         $row['permission'] = 'editsemiprotected'; // B/C
2605                                 }
2606                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2607                         }
2608                         $this->mTitleProtection = $row;
2609                 }
2610                 return $this->mTitleProtection;
2611         }
2612
2613         /**
2614          * Remove any title protection due to page existing
2615          */
2616         public function deleteTitleProtection() {
2617                 $dbw = wfGetDB( DB_MASTER );
2618
2619                 $dbw->delete(
2620                         'protected_titles',
2621                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2622                         __METHOD__
2623                 );
2624                 $this->mTitleProtection = false;
2625         }
2626
2627         /**
2628          * Is this page "semi-protected" - the *only* protection levels are listed
2629          * in $wgSemiprotectedRestrictionLevels?
2630          *
2631          * @param string $action Action to check (default: edit)
2632          * @return bool
2633          */
2634         public function isSemiProtected( $action = 'edit' ) {
2635                 global $wgSemiprotectedRestrictionLevels;
2636
2637                 $restrictions = $this->getRestrictions( $action );
2638                 $semi = $wgSemiprotectedRestrictionLevels;
2639                 if ( !$restrictions || !$semi ) {
2640                         // Not protected, or all protection is full protection
2641                         return false;
2642                 }
2643
2644                 // Remap autoconfirmed to editsemiprotected for BC
2645                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2646                         $semi[$key] = 'editsemiprotected';
2647                 }
2648                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2649                         $restrictions[$key] = 'editsemiprotected';
2650                 }
2651
2652                 return !array_diff( $restrictions, $semi );
2653         }
2654
2655         /**
2656          * Does the title correspond to a protected article?
2657          *
2658          * @param string $action The action the page is protected from,
2659          * by default checks all actions.
2660          * @return bool
2661          */
2662         public function isProtected( $action = '' ) {
2663                 global $wgRestrictionLevels;
2664
2665                 $restrictionTypes = $this->getRestrictionTypes();
2666
2667                 # Special pages have inherent protection
2668                 if ( $this->isSpecialPage() ) {
2669                         return true;
2670                 }
2671
2672                 # Check regular protection levels
2673                 foreach ( $restrictionTypes as $type ) {
2674                         if ( $action == $type || $action == '' ) {
2675                                 $r = $this->getRestrictions( $type );
2676                                 foreach ( $wgRestrictionLevels as $level ) {
2677                                         if ( in_array( $level, $r ) && $level != '' ) {
2678                                                 return true;
2679                                         }
2680                                 }
2681                         }
2682                 }
2683
2684                 return false;
2685         }
2686
2687         /**
2688          * Determines if $user is unable to edit this page because it has been protected
2689          * by $wgNamespaceProtection.
2690          *
2691          * @param User $user User object to check permissions
2692          * @return bool
2693          */
2694         public function isNamespaceProtected( User $user ) {
2695                 global $wgNamespaceProtection;
2696
2697                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2698                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2699                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2700                                         return true;
2701                                 }
2702                         }
2703                 }
2704                 return false;
2705         }
2706
2707         /**
2708          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2709          *
2710          * @return bool If the page is subject to cascading restrictions.
2711          */
2712         public function isCascadeProtected() {
2713                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2714                 return ( $sources > 0 );
2715         }
2716
2717         /**
2718          * Determines whether cascading protection sources have already been loaded from
2719          * the database.
2720          *
2721          * @param bool $getPages True to check if the pages are loaded, or false to check
2722          * if the status is loaded.
2723          * @return bool Whether or not the specified information has been loaded
2724          * @since 1.23
2725          */
2726         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2727                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2728         }
2729
2730         /**
2731          * Cascading protection: Get the source of any cascading restrictions on this page.
2732          *
2733          * @param bool $getPages Whether or not to retrieve the actual pages
2734          *        that the restrictions have come from and the actual restrictions
2735          *        themselves.
2736          * @return array Two elements: First is an array of Title objects of the
2737          *        pages from which cascading restrictions have come, false for
2738          *        none, or true if such restrictions exist but $getPages was not
2739          *        set. Second is an array like that returned by
2740          *        Title::getAllRestrictions(), or an empty array if $getPages is
2741          *        false.
2742          */
2743         public function getCascadeProtectionSources( $getPages = true ) {
2744                 $pagerestrictions = array();
2745
2746                 if ( $this->mCascadeSources !== null && $getPages ) {
2747                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2748                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2749                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2750                 }
2751
2752                 $dbr = wfGetDB( DB_SLAVE );
2753
2754                 if ( $this->getNamespace() == NS_FILE ) {
2755                         $tables = array( 'imagelinks', 'page_restrictions' );
2756                         $where_clauses = array(
2757                                 'il_to' => $this->getDBkey(),
2758                                 'il_from=pr_page',
2759                                 'pr_cascade' => 1
2760                         );
2761                 } else {
2762                         $tables = array( 'templatelinks', 'page_restrictions' );
2763                         $where_clauses = array(
2764                                 'tl_namespace' => $this->getNamespace(),
2765                                 'tl_title' => $this->getDBkey(),
2766                                 'tl_from=pr_page',
2767                                 'pr_cascade' => 1
2768                         );
2769                 }
2770
2771                 if ( $getPages ) {
2772                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2773                                 'pr_expiry', 'pr_type', 'pr_level' );
2774                         $where_clauses[] = 'page_id=pr_page';
2775                         $tables[] = 'page';
2776                 } else {
2777                         $cols = array( 'pr_expiry' );
2778                 }
2779
2780                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2781
2782                 $sources = $getPages ? array() : false;
2783                 $now = wfTimestampNow();
2784
2785                 foreach ( $res as $row ) {
2786                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2787                         if ( $expiry > $now ) {
2788                                 if ( $getPages ) {
2789                                         $page_id = $row->pr_page;
2790                                         $page_ns = $row->page_namespace;
2791                                         $page_title = $row->page_title;
2792                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2793                                         # Add groups needed for each restriction type if its not already there
2794                                         # Make sure this restriction type still exists
2795
2796                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2797                                                 $pagerestrictions[$row->pr_type] = array();
2798                                         }
2799
2800                                         if (
2801                                                 isset( $pagerestrictions[$row->pr_type] )
2802                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2803                                         ) {
2804                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2805                                         }
2806                                 } else {
2807                                         $sources = true;
2808                                 }
2809                         }
2810                 }
2811
2812                 if ( $getPages ) {
2813                         $this->mCascadeSources = $sources;
2814                         $this->mCascadingRestrictions = $pagerestrictions;
2815                 } else {
2816                         $this->mHasCascadingRestrictions = $sources;
2817                 }
2818
2819                 return array( $sources, $pagerestrictions );
2820         }
2821
2822         /**
2823          * Accessor for mRestrictionsLoaded
2824          *
2825          * @return bool Whether or not the page's restrictions have already been
2826          * loaded from the database
2827          * @since 1.23
2828          */
2829         public function areRestrictionsLoaded() {
2830                 return $this->mRestrictionsLoaded;
2831         }
2832
2833         /**
2834          * Accessor/initialisation for mRestrictions
2835          *
2836          * @param string $action Action that permission needs to be checked for
2837          * @return array Restriction levels needed to take the action. All levels are
2838          *     required. Note that restriction levels are normally user rights, but 'sysop'
2839          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2840          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2841          */
2842         public function getRestrictions( $action ) {
2843                 if ( !$this->mRestrictionsLoaded ) {
2844                         $this->loadRestrictions();
2845                 }
2846                 return isset( $this->mRestrictions[$action] )
2847                                 ? $this->mRestrictions[$action]
2848                                 : array();
2849         }
2850
2851         /**
2852          * Accessor/initialisation for mRestrictions
2853          *
2854          * @return array Keys are actions, values are arrays as returned by
2855          *     Title::getRestrictions()
2856          * @since 1.23
2857          */
2858         public function getAllRestrictions() {
2859                 if ( !$this->mRestrictionsLoaded ) {
2860                         $this->loadRestrictions();
2861                 }
2862                 return $this->mRestrictions;
2863         }
2864
2865         /**
2866          * Get the expiry time for the restriction against a given action
2867          *
2868          * @param string $action
2869          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2870          *     or not protected at all, or false if the action is not recognised.
2871          */
2872         public function getRestrictionExpiry( $action ) {
2873                 if ( !$this->mRestrictionsLoaded ) {
2874                         $this->loadRestrictions();
2875                 }
2876                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2877         }
2878
2879         /**
2880          * Returns cascading restrictions for the current article
2881          *
2882          * @return bool
2883          */
2884         function areRestrictionsCascading() {
2885                 if ( !$this->mRestrictionsLoaded ) {
2886                         $this->loadRestrictions();
2887                 }
2888
2889                 return $this->mCascadeRestriction;
2890         }
2891
2892         /**
2893          * Loads a string into mRestrictions array
2894          *
2895          * @param ResultWrapper $res Resource restrictions as an SQL result.
2896          * @param string $oldFashionedRestrictions Comma-separated list of page
2897          *        restrictions from page table (pre 1.10)
2898          */
2899         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2900                 $rows = array();
2901
2902                 foreach ( $res as $row ) {
2903                         $rows[] = $row;
2904                 }
2905
2906                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2907         }
2908
2909         /**
2910          * Compiles list of active page restrictions from both page table (pre 1.10)
2911          * and page_restrictions table for this existing page.
2912          * Public for usage by LiquidThreads.
2913          *
2914          * @param array $rows Array of db result objects
2915          * @param string $oldFashionedRestrictions Comma-separated list of page
2916          *   restrictions from page table (pre 1.10)
2917          */
2918         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2919                 $dbr = wfGetDB( DB_SLAVE );
2920
2921                 $restrictionTypes = $this->getRestrictionTypes();
2922
2923                 foreach ( $restrictionTypes as $type ) {
2924                         $this->mRestrictions[$type] = array();
2925                         $this->mRestrictionsExpiry[$type] = 'infinity';
2926                 }
2927
2928                 $this->mCascadeRestriction = false;
2929
2930                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2931                 if ( $oldFashionedRestrictions !== null ) {
2932                         $this->mOldRestrictions = $oldFashionedRestrictions;
2933                 }
2934
2935                 if ( $this->mOldRestrictions === false ) {
2936                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2937                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2938                 }
2939
2940                 if ( $this->mOldRestrictions != '' ) {
2941                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2942                                 $temp = explode( '=', trim( $restrict ) );
2943                                 if ( count( $temp ) == 1 ) {
2944                                         // old old format should be treated as edit/move restriction
2945                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2946                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2947                                 } else {
2948                                         $restriction = trim( $temp[1] );
2949                                         if ( $restriction != '' ) { // some old entries are empty
2950                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2951                                         }
2952                                 }
2953                         }
2954                 }
2955
2956                 if ( count( $rows ) ) {
2957                         # Current system - load second to make them override.
2958                         $now = wfTimestampNow();
2959
2960                         # Cycle through all the restrictions.
2961                         foreach ( $rows as $row ) {
2962
2963                                 // Don't take care of restrictions types that aren't allowed
2964                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2965                                         continue;
2966                                 }
2967
2968                                 // This code should be refactored, now that it's being used more generally,
2969                                 // But I don't really see any harm in leaving it in Block for now -werdna
2970                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2971
2972                                 // Only apply the restrictions if they haven't expired!
2973                                 if ( !$expiry || $expiry > $now ) {
2974                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2975                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2976
2977                                         $this->mCascadeRestriction |= $row->pr_cascade;
2978                                 }
2979                         }
2980                 }
2981
2982                 $this->mRestrictionsLoaded = true;
2983         }
2984
2985         /**
2986          * Load restrictions from the page_restrictions table
2987          *
2988          * @param string $oldFashionedRestrictions Comma-separated list of page
2989          *   restrictions from page table (pre 1.10)
2990          */
2991         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2992                 if ( !$this->mRestrictionsLoaded ) {
2993                         $dbr = wfGetDB( DB_SLAVE );
2994                         if ( $this->exists() ) {
2995                                 $res = $dbr->select(
2996                                         'page_restrictions',
2997                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2998                                         array( 'pr_page' => $this->getArticleID() ),
2999                                         __METHOD__
3000                                 );
3001
3002                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
3003                         } else {
3004                                 $title_protection = $this->getTitleProtection();
3005
3006                                 if ( $title_protection ) {
3007                                         $now = wfTimestampNow();
3008                                         $expiry = $dbr->decodeExpiry( $title_protection['expiry'] );
3009
3010                                         if ( !$expiry || $expiry > $now ) {
3011                                                 // Apply the restrictions
3012                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3013                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
3014                                         } else { // Get rid of the old restrictions
3015                                                 $this->mTitleProtection = false;
3016                                         }
3017                                 } else {
3018                                         $this->mRestrictionsExpiry['create'] = 'infinity';
3019                                 }
3020                                 $this->mRestrictionsLoaded = true;
3021                         }
3022                 }
3023         }
3024
3025         /**
3026          * Flush the protection cache in this object and force reload from the database.
3027          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3028          */
3029         public function flushRestrictions() {
3030                 $this->mRestrictionsLoaded = false;
3031                 $this->mTitleProtection = null;
3032         }
3033
3034         /**
3035          * Purge expired restrictions from the page_restrictions table
3036          */
3037         static function purgeExpiredRestrictions() {
3038                 if ( wfReadOnly() ) {
3039                         return;
3040                 }
3041
3042                 $method = __METHOD__;
3043                 $dbw = wfGetDB( DB_MASTER );
3044                 $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
3045                         $dbw->delete(
3046                                 'page_restrictions',
3047                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3048                                 $method
3049                         );
3050                         $dbw->delete(
3051                                 'protected_titles',
3052                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3053                                 $method
3054                         );
3055                 } );
3056         }
3057
3058         /**
3059          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3060          *
3061          * @return bool
3062          */
3063         public function hasSubpages() {
3064                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3065                         # Duh
3066                         return false;
3067                 }
3068
3069                 # We dynamically add a member variable for the purpose of this method
3070                 # alone to cache the result.  There's no point in having it hanging
3071                 # around uninitialized in every Title object; therefore we only add it
3072                 # if needed and don't declare it statically.
3073                 if ( $this->mHasSubpages === null ) {
3074                         $this->mHasSubpages = false;
3075                         $subpages = $this->getSubpages( 1 );
3076                         if ( $subpages instanceof TitleArray ) {
3077                                 $this->mHasSubpages = (bool)$subpages->count();
3078                         }
3079                 }
3080
3081                 return $this->mHasSubpages;
3082         }
3083
3084         /**
3085          * Get all subpages of this page.
3086          *
3087          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3088          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3089          *  doesn't allow subpages
3090          */
3091         public function getSubpages( $limit = -1 ) {
3092                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3093                         return array();
3094                 }
3095
3096                 $dbr = wfGetDB( DB_SLAVE );
3097                 $conds['page_namespace'] = $this->getNamespace();
3098                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3099                 $options = array();
3100                 if ( $limit > -1 ) {
3101                         $options['LIMIT'] = $limit;
3102                 }
3103                 $this->mSubpages = TitleArray::newFromResult(
3104                         $dbr->select( 'page',
3105                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3106                                 $conds,
3107                                 __METHOD__,
3108                                 $options
3109                         )
3110                 );
3111                 return $this->mSubpages;
3112         }
3113
3114         /**
3115          * Is there a version of this page in the deletion archive?
3116          *
3117          * @return int The number of archived revisions
3118          */
3119         public function isDeleted() {
3120                 if ( $this->getNamespace() < 0 ) {
3121                         $n = 0;
3122                 } else {
3123                         $dbr = wfGetDB( DB_SLAVE );
3124
3125                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3126                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3127                                 __METHOD__
3128                         );
3129                         if ( $this->getNamespace() == NS_FILE ) {
3130                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3131                                         array( 'fa_name' => $this->getDBkey() ),
3132                                         __METHOD__
3133                                 );
3134                         }
3135                 }
3136                 return (int)$n;
3137         }
3138
3139         /**
3140          * Is there a version of this page in the deletion archive?
3141          *
3142          * @return bool
3143          */
3144         public function isDeletedQuick() {
3145                 if ( $this->getNamespace() < 0 ) {
3146                         return false;
3147                 }
3148                 $dbr = wfGetDB( DB_SLAVE );
3149                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3150                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3151                         __METHOD__
3152                 );
3153                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3154                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3155                                 array( 'fa_name' => $this->getDBkey() ),
3156                                 __METHOD__
3157                         );
3158                 }
3159                 return $deleted;
3160         }
3161
3162         /**
3163          * Get the article ID for this Title from the link cache,
3164          * adding it if necessary
3165          *
3166          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3167          *  for update
3168          * @return int The ID
3169          */
3170         public function getArticleID( $flags = 0 ) {
3171                 if ( $this->getNamespace() < 0 ) {
3172                         $this->mArticleID = 0;
3173                         return $this->mArticleID;
3174                 }
3175                 $linkCache = LinkCache::singleton();
3176                 if ( $flags & self::GAID_FOR_UPDATE ) {
3177                         $oldUpdate = $linkCache->forUpdate( true );
3178                         $linkCache->clearLink( $this );
3179                         $this->mArticleID = $linkCache->addLinkObj( $this );
3180                         $linkCache->forUpdate( $oldUpdate );
3181                 } else {
3182                         if ( -1 == $this->mArticleID ) {
3183                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3184                         }
3185                 }
3186                 return $this->mArticleID;
3187         }
3188
3189         /**
3190          * Is this an article that is a redirect page?
3191          * Uses link cache, adding it if necessary
3192          *
3193          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3194          * @return bool
3195          */
3196         public function isRedirect( $flags = 0 ) {
3197                 if ( !is_null( $this->mRedirect ) ) {
3198                         return $this->mRedirect;
3199                 }
3200                 if ( !$this->getArticleID( $flags ) ) {
3201                         $this->mRedirect = false;
3202                         return $this->mRedirect;
3203                 }
3204
3205                 $linkCache = LinkCache::singleton();
3206                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3207                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3208                 if ( $cached === null ) {
3209                         # Trust LinkCache's state over our own
3210                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3211                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3212                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3213                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3214                         # LinkCache to refresh its data from the master.
3215                         $this->mRedirect = false;
3216                         return $this->mRedirect;
3217                 }
3218
3219                 $this->mRedirect = (bool)$cached;
3220
3221                 return $this->mRedirect;
3222         }
3223
3224         /**
3225          * What is the length of this page?
3226          * Uses link cache, adding it if necessary
3227          *
3228          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3229          * @return int
3230          */
3231         public function getLength( $flags = 0 ) {
3232                 if ( $this->mLength != -1 ) {
3233                         return $this->mLength;
3234                 }
3235                 if ( !$this->getArticleID( $flags ) ) {
3236                         $this->mLength = 0;
3237                         return $this->mLength;
3238                 }
3239                 $linkCache = LinkCache::singleton();
3240                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3241                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3242                 if ( $cached === null ) {
3243                         # Trust LinkCache's state over our own, as for isRedirect()
3244                         $this->mLength = 0;
3245                         return $this->mLength;
3246                 }
3247
3248                 $this->mLength = intval( $cached );
3249
3250                 return $this->mLength;
3251         }
3252
3253         /**
3254          * What is the page_latest field for this page?
3255          *
3256          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3257          * @return int Int or 0 if the page doesn't exist
3258          */
3259         public function getLatestRevID( $flags = 0 ) {
3260                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3261                         return intval( $this->mLatestID );
3262                 }
3263                 if ( !$this->getArticleID( $flags ) ) {
3264                         $this->mLatestID = 0;
3265                         return $this->mLatestID;
3266                 }
3267                 $linkCache = LinkCache::singleton();
3268                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3269                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3270                 if ( $cached === null ) {
3271                         # Trust LinkCache's state over our own, as for isRedirect()
3272                         $this->mLatestID = 0;
3273                         return $this->mLatestID;
3274                 }
3275
3276                 $this->mLatestID = intval( $cached );
3277
3278                 return $this->mLatestID;
3279         }
3280
3281         /**
3282          * This clears some fields in this object, and clears any associated
3283          * keys in the "bad links" section of the link cache.
3284          *
3285          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3286          * loading of the new page_id. It's also called from
3287          * WikiPage::doDeleteArticleReal()
3288          *
3289          * @param int $newid The new Article ID
3290          */
3291         public function resetArticleID( $newid ) {
3292                 $linkCache = LinkCache::singleton();
3293                 $linkCache->clearLink( $this );
3294
3295                 if ( $newid === false ) {
3296                         $this->mArticleID = -1;
3297                 } else {
3298                         $this->mArticleID = intval( $newid );
3299                 }
3300                 $this->mRestrictionsLoaded = false;
3301                 $this->mRestrictions = array();
3302                 $this->mOldRestrictions = false;
3303                 $this->mRedirect = null;
3304                 $this->mLength = -1;
3305                 $this->mLatestID = false;
3306                 $this->mContentModel = false;
3307                 $this->mEstimateRevisions = null;
3308                 $this->mPageLanguage = false;
3309                 $this->mDbPageLanguage = null;
3310                 $this->mIsBigDeletion = null;
3311         }
3312
3313         public static function clearCaches() {
3314                 $linkCache = LinkCache::singleton();
3315                 $linkCache->clear();
3316
3317                 $titleCache = self::getTitleCache();
3318                 $titleCache->clear();
3319         }
3320
3321         /**
3322          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3323          *
3324          * @param string $text Containing title to capitalize
3325          * @param int $ns Namespace index, defaults to NS_MAIN
3326          * @return string Containing capitalized title
3327          */
3328         public static function capitalize( $text, $ns = NS_MAIN ) {
3329                 global $wgContLang;
3330
3331                 if ( MWNamespace::isCapitalized( $ns ) ) {
3332                         return $wgContLang->ucfirst( $text );
3333                 } else {
3334                         return $text;
3335                 }
3336         }
3337
3338         /**
3339          * Secure and split - main initialisation function for this object
3340          *
3341          * Assumes that mDbkeyform has been set, and is urldecoded
3342          * and uses underscores, but not otherwise munged.  This function
3343          * removes illegal characters, splits off the interwiki and
3344          * namespace prefixes, sets the other forms, and canonicalizes
3345          * everything.
3346          *
3347          * @throws MalformedTitleException On invalid titles
3348          * @return bool True on success
3349          */
3350         private function secureAndSplit() {
3351                 # Initialisation
3352                 $this->mInterwiki = '';
3353                 $this->mFragment = '';
3354                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3355
3356                 $dbkey = $this->mDbkeyform;
3357
3358                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3359                 //        the parsing code with Title, while avoiding massive refactoring.
3360                 // @todo: get rid of secureAndSplit, refactor parsing code.
3361                 $titleParser = self::getTitleParser();
3362                 // MalformedTitleException can be thrown here
3363                 $parts = $titleParser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3364
3365                 # Fill fields
3366                 $this->setFragment( '#' . $parts['fragment'] );
3367                 $this->mInterwiki = $parts['interwiki'];
3368                 $this->mLocalInterwiki = $parts['local_interwiki'];
3369                 $this->mNamespace = $parts['namespace'];
3370                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3371
3372                 $this->mDbkeyform = $parts['dbkey'];
3373                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3374                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3375
3376                 # We already know that some pages won't be in the database!
3377                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3378                         $this->mArticleID = 0;
3379                 }
3380
3381                 return true;
3382         }
3383
3384         /**
3385          * Get an array of Title objects linking to this Title
3386          * Also stores the IDs in the link cache.
3387          *
3388          * WARNING: do not use this function on arbitrary user-supplied titles!
3389          * On heavily-used templates it will max out the memory.
3390          *
3391          * @param array $options May be FOR UPDATE
3392          * @param string $table Table name
3393          * @param string $prefix Fields prefix
3394          * @return Title[] Array of Title objects linking here
3395          */
3396         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3397                 if ( count( $options ) > 0 ) {
3398                         $db = wfGetDB( DB_MASTER );
3399                 } else {
3400                         $db = wfGetDB( DB_SLAVE );
3401                 }
3402
3403                 $res = $db->select(
3404                         array( 'page', $table ),
3405                         self::getSelectFields(),
3406                         array(
3407                                 "{$prefix}_from=page_id",
3408                                 "{$prefix}_namespace" => $this->getNamespace(),
3409                                 "{$prefix}_title" => $this->getDBkey() ),
3410                         __METHOD__,
3411                         $options
3412                 );
3413
3414                 $retVal = array();
3415                 if ( $res->numRows() ) {
3416                         $linkCache = LinkCache::singleton();
3417                         foreach ( $res as $row ) {
3418                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3419                                 if ( $titleObj ) {
3420                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3421                                         $retVal[] = $titleObj;
3422                                 }
3423                         }
3424                 }
3425                 return $retVal;
3426         }
3427
3428         /**
3429          * Get an array of Title objects using this Title as a template
3430          * Also stores the IDs in the link cache.
3431          *
3432          * WARNING: do not use this function on arbitrary user-supplied titles!
3433          * On heavily-used templates it will max out the memory.
3434          *
3435          * @param array $options May be FOR UPDATE
3436          * @return Title[] Array of Title the Title objects linking here
3437          */
3438         public function getTemplateLinksTo( $options = array() ) {
3439                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3440         }
3441
3442         /**
3443          * Get an array of Title objects linked from this Title
3444          * Also stores the IDs in the link cache.
3445          *
3446          * WARNING: do not use this function on arbitrary user-supplied titles!
3447          * On heavily-used templates it will max out the memory.
3448          *
3449          * @param array $options May be FOR UPDATE
3450          * @param string $table Table name
3451          * @param string $prefix Fields prefix
3452          * @return array Array of Title objects linking here
3453          */
3454         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3455                 $id = $this->getArticleID();
3456
3457                 # If the page doesn't exist; there can't be any link from this page
3458                 if ( !$id ) {
3459                         return array();
3460                 }
3461
3462                 if ( count( $options ) > 0 ) {
3463                         $db = wfGetDB( DB_MASTER );
3464                 } else {
3465                         $db = wfGetDB( DB_SLAVE );
3466                 }
3467
3468                 $blNamespace = "{$prefix}_namespace";
3469                 $blTitle = "{$prefix}_title";
3470
3471                 $res = $db->select(
3472                         array( $table, 'page' ),
3473                         array_merge(
3474                                 array( $blNamespace, $blTitle ),
3475                                 WikiPage::selectFields()
3476                         ),
3477                         array( "{$prefix}_from" => $id ),
3478                         __METHOD__,
3479                         $options,
3480                         array( 'page' => array(
3481                                 'LEFT JOIN',
3482                                 array( "page_namespace=$blNamespace", "page_title=$blTitle" )
3483                         ) )
3484                 );
3485
3486                 $retVal = array();
3487                 $linkCache = LinkCache::singleton();
3488                 foreach ( $res as $row ) {
3489                         if ( $row->page_id ) {
3490                                 $titleObj = Title::newFromRow( $row );
3491                         } else {
3492                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3493                                 $linkCache->addBadLinkObj( $titleObj );
3494                         }
3495                         $retVal[] = $titleObj;
3496                 }
3497
3498                 return $retVal;
3499         }
3500
3501         /**
3502          * Get an array of Title objects used on this Title as a template
3503          * Also stores the IDs in the link cache.
3504          *
3505          * WARNING: do not use this function on arbitrary user-supplied titles!
3506          * On heavily-used templates it will max out the memory.
3507          *
3508          * @param array $options May be FOR UPDATE
3509          * @return Title[] Array of Title the Title objects used here
3510          */
3511         public function getTemplateLinksFrom( $options = array() ) {
3512                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3513         }
3514
3515         /**
3516          * Get an array of Title objects referring to non-existent articles linked
3517          * from this page.
3518          *
3519          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3520          *   should use redirect table in this case).
3521          * @return Title[] Array of Title the Title objects
3522          */
3523         public function getBrokenLinksFrom() {
3524                 if ( $this->getArticleID() == 0 ) {
3525                         # All links from article ID 0 are false positives
3526                         return array();
3527                 }
3528
3529                 $dbr = wfGetDB( DB_SLAVE );
3530                 $res = $dbr->select(
3531                         array( 'page', 'pagelinks' ),
3532                         array( 'pl_namespace', 'pl_title' ),
3533                         array(
3534                                 'pl_from' => $this->getArticleID(),
3535                                 'page_namespace IS NULL'
3536                         ),
3537                         __METHOD__, array(),
3538                         array(
3539                                 'page' => array(
3540                                         'LEFT JOIN',
3541                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3542                                 )
3543                         )
3544                 );
3545
3546                 $retVal = array();
3547                 foreach ( $res as $row ) {
3548                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3549                 }
3550                 return $retVal;
3551         }
3552
3553         /**
3554          * Get a list of URLs to purge from the Squid cache when this
3555          * page changes
3556          *
3557          * @return string[] Array of String the URLs
3558          */
3559         public function getSquidURLs() {
3560                 $urls = array(
3561                         $this->getInternalURL(),
3562                         $this->getInternalURL( 'action=history' )
3563                 );
3564
3565                 $pageLang = $this->getPageLanguage();
3566                 if ( $pageLang->hasVariants() ) {
3567                         $variants = $pageLang->getVariants();
3568                         foreach ( $variants as $vCode ) {
3569                                 $urls[] = $this->getInternalURL( '', $vCode );
3570                         }
3571                 }
3572
3573                 // If we are looking at a css/js user subpage, purge the action=raw.
3574                 if ( $this->isJsSubpage() ) {
3575                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3576                 } elseif ( $this->isCssSubpage() ) {
3577                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3578                 }
3579
3580                 Hooks::run( 'TitleSquidURLs', array( $this, &$urls ) );
3581                 return $urls;
3582         }
3583
3584         /**
3585          * Purge all applicable Squid URLs
3586          */
3587         public function purgeSquid() {
3588                 global $wgUseSquid;
3589                 if ( $wgUseSquid ) {
3590                         $urls = $this->getSquidURLs();
3591                         $u = new SquidUpdate( $urls );
3592                         $u->doUpdate();
3593                 }
3594         }
3595
3596         /**
3597          * Move this page without authentication
3598          *
3599          * @deprecated since 1.25 use MovePage class instead
3600          * @param Title $nt The new page Title
3601          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3602          */
3603         public function moveNoAuth( &$nt ) {
3604                 wfDeprecated( __METHOD__, '1.25' );
3605                 return $this->moveTo( $nt, false );
3606         }
3607
3608         /**
3609          * Check whether a given move operation would be valid.
3610          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3611          *
3612          * @deprecated since 1.25, use MovePage's methods instead
3613          * @param Title $nt The new title
3614          * @param bool $auth Whether to check user permissions (uses $wgUser)
3615          * @param string $reason Is the log summary of the move, used for spam checking
3616          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3617          */
3618         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3619                 global $wgUser;
3620
3621                 if ( !( $nt instanceof Title ) ) {
3622                         // Normally we'd add this to $errors, but we'll get
3623                         // lots of syntax errors if $nt is not an object
3624                         return array( array( 'badtitletext' ) );
3625                 }
3626
3627                 $mp = new MovePage( $this, $nt );
3628                 $errors = $mp->isValidMove()->getErrorsArray();
3629                 if ( $auth ) {
3630                         $errors = wfMergeErrorArrays(
3631                                 $errors,
3632                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3633                         );
3634                 }
3635
3636                 return $errors ?: true;
3637         }
3638
3639         /**
3640          * Check if the requested move target is a valid file move target
3641          * @todo move this to MovePage
3642          * @param Title $nt Target title
3643          * @return array List of errors
3644          */
3645         protected function validateFileMoveOperation( $nt ) {
3646                 global $wgUser;
3647
3648                 $errors = array();
3649
3650                 $destFile = wfLocalFile( $nt );
3651                 $destFile->load( File::READ_LATEST );
3652                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3653                         && !$destFile->exists() && wfFindFile( $nt )
3654                 ) {
3655                         $errors[] = array( 'file-exists-sharedrepo' );
3656                 }
3657
3658                 return $errors;
3659         }
3660
3661         /**
3662          * Move a title to a new location
3663          *
3664          * @deprecated since 1.25, use the MovePage class instead
3665          * @param Title $nt The new title
3666          * @param bool $auth Indicates whether $wgUser's permissions
3667          *  should be checked
3668          * @param string $reason The reason for the move
3669          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3670          *  Ignored if the user doesn't have the suppressredirect right.
3671          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3672          */
3673         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3674                 global $wgUser;
3675                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3676                 if ( is_array( $err ) ) {
3677                         // Auto-block user's IP if the account was "hard" blocked
3678                         $wgUser->spreadAnyEditBlock();
3679                         return $err;
3680                 }
3681                 // Check suppressredirect permission
3682                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3683                         $createRedirect = true;
3684                 }
3685
3686                 $mp = new MovePage( $this, $nt );
3687                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3688                 if ( $status->isOK() ) {
3689                         return true;
3690                 } else {
3691                         return $status->getErrorsArray();
3692                 }
3693         }
3694
3695         /**
3696          * Move this page's subpages to be subpages of $nt
3697          *
3698          * @param Title $nt Move target
3699          * @param bool $auth Whether $wgUser's permissions should be checked
3700          * @param string $reason The reason for the move
3701          * @param bool $createRedirect Whether to create redirects from the old subpages to
3702          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3703          * @return array Array with old page titles as keys, and strings (new page titles) or
3704          *     arrays (errors) as values, or an error array with numeric indices if no pages
3705          *     were moved
3706          */
3707         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3708                 global $wgMaximumMovedPages;
3709                 // Check permissions
3710                 if ( !$this->userCan( 'move-subpages' ) ) {
3711                         return array( 'cant-move-subpages' );
3712                 }
3713                 // Do the source and target namespaces support subpages?
3714                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3715                         return array( 'namespace-nosubpages',
3716                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3717                 }
3718                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3719                         return array( 'namespace-nosubpages',
3720                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3721                 }
3722
3723                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3724                 $retval = array();
3725                 $count = 0;
3726                 foreach ( $subpages as $oldSubpage ) {
3727                         $count++;
3728                         if ( $count > $wgMaximumMovedPages ) {
3729                                 $retval[$oldSubpage->getPrefixedText()] =
3730                                                 array( 'movepage-max-pages',
3731                                                         $wgMaximumMovedPages );
3732                                 break;
3733                         }
3734
3735                         // We don't know whether this function was called before
3736                         // or after moving the root page, so check both
3737                         // $this and $nt
3738                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3739                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3740                         ) {
3741                                 // When moving a page to a subpage of itself,
3742                                 // don't move it twice
3743                                 continue;
3744                         }
3745                         $newPageName = preg_replace(
3746                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3747                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3748                                         $oldSubpage->getDBkey() );
3749                         if ( $oldSubpage->isTalkPage() ) {
3750                                 $newNs = $nt->getTalkPage()->getNamespace();
3751                         } else {
3752                                 $newNs = $nt->getSubjectPage()->getNamespace();
3753                         }
3754                         # Bug 14385: we need makeTitleSafe because the new page names may
3755                         # be longer than 255 characters.
3756                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3757
3758                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3759                         if ( $success === true ) {
3760                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3761                         } else {
3762                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3763                         }
3764                 }
3765                 return $retval;
3766         }
3767
3768         /**
3769          * Checks if this page is just a one-rev redirect.
3770          * Adds lock, so don't use just for light purposes.
3771          *
3772          * @return bool
3773          */
3774         public function isSingleRevRedirect() {
3775                 global $wgContentHandlerUseDB;
3776
3777                 $dbw = wfGetDB( DB_MASTER );
3778
3779                 # Is it a redirect?
3780                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
3781                 if ( $wgContentHandlerUseDB ) {
3782                         $fields[] = 'page_content_model';
3783                 }
3784
3785                 $row = $dbw->selectRow( 'page',
3786                         $fields,
3787                         $this->pageCond(),
3788                         __METHOD__,
3789                         array( 'FOR UPDATE' )
3790                 );
3791                 # Cache some fields we may want
3792                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3793                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3794                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3795                 $this->mContentModel = $row && isset( $row->page_content_model )
3796                         ? strval( $row->page_content_model )
3797                         : false;
3798
3799                 if ( !$this->mRedirect ) {
3800                         return false;
3801                 }
3802                 # Does the article have a history?
3803                 $row = $dbw->selectField( array( 'page', 'revision' ),
3804                         'rev_id',
3805                         array( 'page_namespace' => $this->getNamespace(),
3806                                 'page_title' => $this->getDBkey(),
3807                                 'page_id=rev_page',
3808                                 'page_latest != rev_id'
3809                         ),
3810                         __METHOD__,
3811                         array( 'FOR UPDATE' )
3812                 );
3813                 # Return true if there was no history
3814                 return ( $row === false );
3815         }
3816
3817         /**
3818          * Checks if $this can be moved to a given Title
3819          * - Selects for update, so don't call it unless you mean business
3820          *
3821          * @deprecated since 1.25, use MovePage's methods instead
3822          * @param Title $nt The new title to check
3823          * @return bool
3824          */
3825         public function isValidMoveTarget( $nt ) {
3826                 # Is it an existing file?
3827                 if ( $nt->getNamespace() == NS_FILE ) {
3828                         $file = wfLocalFile( $nt );
3829                         $file->load( File::READ_LATEST );
3830                         if ( $file->exists() ) {
3831                                 wfDebug( __METHOD__ . ": file exists\n" );
3832                                 return false;
3833                         }
3834                 }
3835                 # Is it a redirect with no history?
3836                 if ( !$nt->isSingleRevRedirect() ) {
3837                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3838                         return false;
3839                 }
3840                 # Get the article text
3841                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3842                 if ( !is_object( $rev ) ) {
3843                         return false;
3844                 }
3845                 $content = $rev->getContent();
3846                 # Does the redirect point to the source?
3847                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3848                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3849
3850                 if ( $redirTitle ) {
3851                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3852                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3853                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3854                                 return false;
3855                         } else {
3856                                 return true;
3857                         }
3858                 } else {
3859                         # Fail safe (not a redirect after all. strange.)
3860                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3861                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3862                         return false;
3863                 }
3864         }
3865
3866         /**
3867          * Get categories to which this Title belongs and return an array of
3868          * categories' names.
3869          *
3870          * @return array Array of parents in the form:
3871          *        $parent => $currentarticle
3872          */
3873         public function getParentCategories() {
3874                 global $wgContLang;
3875
3876                 $data = array();
3877
3878                 $titleKey = $this->getArticleID();
3879
3880                 if ( $titleKey === 0 ) {
3881                         return $data;
3882                 }
3883
3884                 $dbr = wfGetDB( DB_SLAVE );
3885
3886                 $res = $dbr->select(
3887                         'categorylinks',
3888                         'cl_to',
3889                         array( 'cl_from' => $titleKey ),
3890                         __METHOD__
3891                 );
3892
3893                 if ( $res->numRows() > 0 ) {
3894                         foreach ( $res as $row ) {
3895                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3896                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3897                         }
3898                 }
3899                 return $data;
3900         }
3901
3902         /**
3903          * Get a tree of parent categories
3904          *
3905          * @param array $children Array with the children in the keys, to check for circular refs
3906          * @return array Tree of parent categories
3907          */
3908         public function getParentCategoryTree( $children = array() ) {
3909                 $stack = array();
3910                 $parents = $this->getParentCategories();
3911
3912                 if ( $parents ) {
3913                         foreach ( $parents as $parent => $current ) {
3914                                 if ( array_key_exists( $parent, $children ) ) {
3915                                         # Circular reference
3916                                         $stack[$parent] = array();
3917                                 } else {
3918                                         $nt = Title::newFromText( $parent );
3919                                         if ( $nt ) {
3920                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
3921                                         }
3922                                 }
3923                         }
3924                 }
3925
3926                 return $stack;
3927         }
3928
3929         /**
3930          * Get an associative array for selecting this title from
3931          * the "page" table
3932          *
3933          * @return array Array suitable for the $where parameter of DB::select()
3934          */
3935         public function pageCond() {
3936                 if ( $this->mArticleID > 0 ) {
3937                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3938                         return array( 'page_id' => $this->mArticleID );
3939                 } else {
3940                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
3941                 }
3942         }
3943
3944         /**
3945          * Get the revision ID of the previous revision
3946          *
3947          * @param int $revId Revision ID. Get the revision that was before this one.
3948          * @param int $flags Title::GAID_FOR_UPDATE
3949          * @return int|bool Old revision ID, or false if none exists
3950          */
3951         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3952                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3953                 $revId = $db->selectField( 'revision', 'rev_id',
3954                         array(
3955                                 'rev_page' => $this->getArticleID( $flags ),
3956                                 'rev_id < ' . intval( $revId )
3957                         ),
3958                         __METHOD__,
3959                         array( 'ORDER BY' => 'rev_id DESC' )
3960                 );
3961
3962                 if ( $revId === false ) {
3963                         return false;
3964                 } else {
3965                         return intval( $revId );
3966                 }
3967         }
3968
3969         /**
3970          * Get the revision ID of the next revision
3971          *
3972          * @param int $revId Revision ID. Get the revision that was after this one.
3973          * @param int $flags Title::GAID_FOR_UPDATE
3974          * @return int|bool Next revision ID, or false if none exists
3975          */
3976         public function getNextRevisionID( $revId, $flags = 0 ) {
3977                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3978                 $revId = $db->selectField( 'revision', 'rev_id',
3979                         array(
3980                                 'rev_page' => $this->getArticleID( $flags ),
3981                                 'rev_id > ' . intval( $revId )
3982                         ),
3983                         __METHOD__,
3984                         array( 'ORDER BY' => 'rev_id' )
3985                 );
3986
3987                 if ( $revId === false ) {
3988                         return false;
3989                 } else {
3990                         return intval( $revId );
3991                 }
3992         }
3993
3994         /**
3995          * Get the first revision of the page
3996          *
3997          * @param int $flags Title::GAID_FOR_UPDATE
3998          * @return Revision|null If page doesn't exist
3999          */
4000         public function getFirstRevision( $flags = 0 ) {
4001                 $pageId = $this->getArticleID( $flags );
4002                 if ( $pageId ) {
4003                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4004                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4005                                 array( 'rev_page' => $pageId ),
4006                                 __METHOD__,
4007                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4008                         );
4009                         if ( $row ) {
4010                                 return new Revision( $row );
4011                         }
4012                 }
4013                 return null;
4014         }
4015
4016         /**
4017          * Get the oldest revision timestamp of this page
4018          *
4019          * @param int $flags Title::GAID_FOR_UPDATE
4020          * @return string MW timestamp
4021          */
4022         public function getEarliestRevTime( $flags = 0 ) {
4023                 $rev = $this->getFirstRevision( $flags );
4024                 return $rev ? $rev->getTimestamp() : null;
4025         }
4026
4027         /**
4028          * Check if this is a new page
4029          *
4030          * @return bool
4031          */
4032         public function isNewPage() {
4033                 $dbr = wfGetDB( DB_SLAVE );
4034                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4035         }
4036
4037         /**
4038          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4039          *
4040          * @return bool
4041          */
4042         public function isBigDeletion() {
4043                 global $wgDeleteRevisionsLimit;
4044
4045                 if ( !$wgDeleteRevisionsLimit ) {
4046                         return false;
4047                 }
4048
4049                 if ( $this->mIsBigDeletion === null ) {
4050                         $dbr = wfGetDB( DB_SLAVE );
4051
4052                         $revCount = $dbr->selectRowCount(
4053                                 'revision',
4054                                 '1',
4055                                 array( 'rev_page' => $this->getArticleID() ),
4056                                 __METHOD__,
4057                                 array( 'LIMIT' => $wgDeleteRevisionsLimit + 1 )
4058                         );
4059
4060                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4061                 }
4062
4063                 return $this->mIsBigDeletion;
4064         }
4065
4066         /**
4067          * Get the approximate revision count of this page.
4068          *
4069          * @return int
4070          */
4071         public function estimateRevisionCount() {
4072                 if ( !$this->exists() ) {
4073                         return 0;
4074                 }
4075
4076                 if ( $this->mEstimateRevisions === null ) {
4077                         $dbr = wfGetDB( DB_SLAVE );
4078                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4079                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4080                 }
4081
4082                 return $this->mEstimateRevisions;
4083         }
4084
4085         /**
4086          * Get the number of revisions between the given revision.
4087          * Used for diffs and other things that really need it.
4088          *
4089          * @param int|Revision $old Old revision or rev ID (first before range)
4090          * @param int|Revision $new New revision or rev ID (first after range)
4091          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4092          * @return int Number of revisions between these revisions.
4093          */
4094         public function countRevisionsBetween( $old, $new, $max = null ) {
4095                 if ( !( $old instanceof Revision ) ) {
4096                         $old = Revision::newFromTitle( $this, (int)$old );
4097                 }
4098                 if ( !( $new instanceof Revision ) ) {
4099                         $new = Revision::newFromTitle( $this, (int)$new );
4100                 }
4101                 if ( !$old || !$new ) {
4102                         return 0; // nothing to compare
4103                 }
4104                 $dbr = wfGetDB( DB_SLAVE );
4105                 $conds = array(
4106                         'rev_page' => $this->getArticleID(),
4107                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4108                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4109                 );
4110                 if ( $max !== null ) {
4111                         return $dbr->selectRowCount( 'revision', '1',
4112                                 $conds,
4113                                 __METHOD__,
4114                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4115                         );
4116                 } else {
4117                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4118                 }
4119         }
4120
4121         /**
4122          * Get the authors between the given revisions or revision IDs.
4123          * Used for diffs and other things that really need it.
4124          *
4125          * @since 1.23
4126          *
4127          * @param int|Revision $old Old revision or rev ID (first before range by default)
4128          * @param int|Revision $new New revision or rev ID (first after range by default)
4129          * @param int $limit Maximum number of authors
4130          * @param string|array $options (Optional): Single option, or an array of options:
4131          *     'include_old' Include $old in the range; $new is excluded.
4132          *     'include_new' Include $new in the range; $old is excluded.
4133          *     'include_both' Include both $old and $new in the range.
4134          *     Unknown option values are ignored.
4135          * @return array|null Names of revision authors in the range; null if not both revisions exist
4136          */
4137         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4138                 if ( !( $old instanceof Revision ) ) {
4139                         $old = Revision::newFromTitle( $this, (int)$old );
4140                 }
4141                 if ( !( $new instanceof Revision ) ) {
4142                         $new = Revision::newFromTitle( $this, (int)$new );
4143                 }
4144                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4145                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4146                 // in the sanity check below?
4147                 if ( !$old || !$new ) {
4148                         return null; // nothing to compare
4149                 }
4150                 $authors = array();
4151                 $old_cmp = '>';
4152                 $new_cmp = '<';
4153                 $options = (array)$options;
4154                 if ( in_array( 'include_old', $options ) ) {
4155                         $old_cmp = '>=';
4156                 }
4157                 if ( in_array( 'include_new', $options ) ) {
4158                         $new_cmp = '<=';
4159                 }
4160                 if ( in_array( 'include_both', $options ) ) {
4161                         $old_cmp = '>=';
4162                         $new_cmp = '<=';
4163                 }
4164                 // No DB query needed if $old and $new are the same or successive revisions:
4165                 if ( $old->getId() === $new->getId() ) {
4166                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4167                                 array() :
4168                                 array( $old->getUserText( Revision::RAW ) );
4169                 } elseif ( $old->getId() === $new->getParentId() ) {
4170                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4171                                 $authors[] = $old->getUserText( Revision::RAW );
4172                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4173                                         $authors[] = $new->getUserText( Revision::RAW );
4174                                 }
4175                         } elseif ( $old_cmp === '>=' ) {
4176                                 $authors[] = $old->getUserText( Revision::RAW );
4177                         } elseif ( $new_cmp === '<=' ) {
4178                                 $authors[] = $new->getUserText( Revision::RAW );
4179                         }
4180                         return $authors;
4181                 }
4182                 $dbr = wfGetDB( DB_SLAVE );
4183                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4184                         array(
4185                                 'rev_page' => $this->getArticleID(),
4186                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4187                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4188                         ), __METHOD__,
4189                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4190                 );
4191                 foreach ( $res as $row ) {
4192                         $authors[] = $row->rev_user_text;
4193                 }
4194                 return $authors;
4195         }
4196
4197         /**
4198          * Get the number of authors between the given revisions or revision IDs.
4199          * Used for diffs and other things that really need it.
4200          *
4201          * @param int|Revision $old Old revision or rev ID (first before range by default)
4202          * @param int|Revision $new New revision or rev ID (first after range by default)
4203          * @param int $limit Maximum number of authors
4204          * @param string|array $options (Optional): Single option, or an array of options:
4205          *     'include_old' Include $old in the range; $new is excluded.
4206          *     'include_new' Include $new in the range; $old is excluded.
4207          *     'include_both' Include both $old and $new in the range.
4208          *     Unknown option values are ignored.
4209          * @return int Number of revision authors in the range; zero if not both revisions exist
4210          */
4211         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4212                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4213                 return $authors ? count( $authors ) : 0;
4214         }
4215
4216         /**
4217          * Compare with another title.
4218          *
4219          * @param Title $title
4220          * @return bool
4221          */
4222         public function equals( Title $title ) {
4223                 // Note: === is necessary for proper matching of number-like titles.
4224                 return $this->getInterwiki() === $title->getInterwiki()
4225                         && $this->getNamespace() == $title->getNamespace()
4226                         && $this->getDBkey() === $title->getDBkey();
4227         }
4228
4229         /**
4230          * Check if this title is a subpage of another title
4231          *
4232          * @param Title $title
4233          * @return bool
4234          */
4235         public function isSubpageOf( Title $title ) {
4236                 return $this->getInterwiki() === $title->getInterwiki()
4237                         && $this->getNamespace() == $title->getNamespace()
4238                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4239         }
4240
4241         /**
4242          * Check if page exists.  For historical reasons, this function simply
4243          * checks for the existence of the title in the page table, and will
4244          * thus return false for interwiki links, special pages and the like.
4245          * If you want to know if a title can be meaningfully viewed, you should
4246          * probably call the isKnown() method instead.
4247          *
4248          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4249          *   from master/for update
4250          * @return bool
4251          */
4252         public function exists( $flags = 0 ) {
4253                 $exists = $this->getArticleID( $flags ) != 0;
4254                 Hooks::run( 'TitleExists', array( $this, &$exists ) );
4255                 return $exists;
4256         }
4257
4258         /**
4259          * Should links to this title be shown as potentially viewable (i.e. as
4260          * "bluelinks"), even if there's no record by this title in the page
4261          * table?
4262          *
4263          * This function is semi-deprecated for public use, as well as somewhat
4264          * misleadingly named.  You probably just want to call isKnown(), which
4265          * calls this function internally.
4266          *
4267          * (ISSUE: Most of these checks are cheap, but the file existence check
4268          * can potentially be quite expensive.  Including it here fixes a lot of
4269          * existing code, but we might want to add an optional parameter to skip
4270          * it and any other expensive checks.)
4271          *
4272          * @return bool
4273          */
4274         public function isAlwaysKnown() {
4275                 $isKnown = null;
4276
4277                 /**
4278                  * Allows overriding default behavior for determining if a page exists.
4279                  * If $isKnown is kept as null, regular checks happen. If it's
4280                  * a boolean, this value is returned by the isKnown method.
4281                  *
4282                  * @since 1.20
4283                  *
4284                  * @param Title $title
4285                  * @param bool|null $isKnown
4286                  */
4287                 Hooks::run( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4288
4289                 if ( !is_null( $isKnown ) ) {
4290                         return $isKnown;
4291                 }
4292
4293                 if ( $this->isExternal() ) {
4294                         return true;  // any interwiki link might be viewable, for all we know
4295                 }
4296
4297                 switch ( $this->mNamespace ) {
4298                         case NS_MEDIA:
4299                         case NS_FILE:
4300                                 // file exists, possibly in a foreign repo
4301                                 return (bool)wfFindFile( $this );
4302                         case NS_SPECIAL:
4303                                 // valid special page
4304                                 return SpecialPageFactory::exists( $this->getDBkey() );
4305                         case NS_MAIN:
4306                                 // selflink, possibly with fragment
4307                                 return $this->mDbkeyform == '';
4308                         case NS_MEDIAWIKI:
4309                                 // known system message
4310                                 return $this->hasSourceText() !== false;
4311                         default:
4312                                 return false;
4313                 }
4314         }
4315
4316         /**
4317          * Does this title refer to a page that can (or might) be meaningfully
4318          * viewed?  In particular, this function may be used to determine if
4319          * links to the title should be rendered as "bluelinks" (as opposed to
4320          * "redlinks" to non-existent pages).
4321          * Adding something else to this function will cause inconsistency
4322          * since LinkHolderArray calls isAlwaysKnown() and does its own
4323          * page existence check.
4324          *
4325          * @return bool
4326          */
4327         public function isKnown() {
4328                 return $this->isAlwaysKnown() || $this->exists();
4329         }
4330
4331         /**
4332          * Does this page have source text?
4333          *
4334          * @return bool
4335          */
4336         public function hasSourceText() {
4337                 if ( $this->exists() ) {
4338                         return true;
4339                 }
4340
4341                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4342                         // If the page doesn't exist but is a known system message, default
4343                         // message content will be displayed, same for language subpages-
4344                         // Use always content language to avoid loading hundreds of languages
4345                         // to get the link color.
4346                         global $wgContLang;
4347                         list( $name, ) = MessageCache::singleton()->figureMessage(
4348                                 $wgContLang->lcfirst( $this->getText() )
4349                         );
4350                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4351                         return $message->exists();
4352                 }
4353
4354                 return false;
4355         }
4356
4357         /**
4358          * Get the default message text or false if the message doesn't exist
4359          *
4360          * @return string|bool
4361          */
4362         public function getDefaultMessageText() {
4363                 global $wgContLang;
4364
4365                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4366                         return false;
4367                 }
4368
4369                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4370                         $wgContLang->lcfirst( $this->getText() )
4371                 );
4372                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4373
4374                 if ( $message->exists() ) {
4375                         return $message->plain();
4376                 } else {
4377                         return false;
4378                 }
4379         }
4380
4381         /**
4382          * Updates page_touched for this page; called from LinksUpdate.php
4383          *
4384          * @param string $purgeTime [optional] TS_MW timestamp
4385          * @return bool True if the update succeeded
4386          */
4387         public function invalidateCache( $purgeTime = null ) {
4388                 if ( wfReadOnly() ) {
4389                         return false;
4390                 }
4391
4392                 if ( $this->mArticleID === 0 ) {
4393                         return true; // avoid gap locking if we know it's not there
4394                 }
4395
4396                 $method = __METHOD__;
4397                 $dbw = wfGetDB( DB_MASTER );
4398                 $conds = $this->pageCond();
4399                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method, $purgeTime ) {
4400                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4401
4402                         $dbw->update(
4403                                 'page',
4404                                 array( 'page_touched' => $dbTimestamp ),
4405                                 $conds + array( 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ),
4406                                 $method
4407                         );
4408                 } );
4409
4410                 return true;
4411         }
4412
4413         /**
4414          * Update page_touched timestamps and send squid purge messages for
4415          * pages linking to this title. May be sent to the job queue depending
4416          * on the number of links. Typically called on create and delete.
4417          */
4418         public function touchLinks() {
4419                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4420                 if ( $this->getNamespace() == NS_CATEGORY ) {
4421                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4422                 }
4423         }
4424
4425         /**
4426          * Get the last touched timestamp
4427          *
4428          * @param IDatabase $db Optional db
4429          * @return string Last-touched timestamp
4430          */
4431         public function getTouched( $db = null ) {
4432                 if ( $db === null ) {
4433                         $db = wfGetDB( DB_SLAVE );
4434                 }
4435                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4436                 return $touched;
4437         }
4438
4439         /**
4440          * Get the timestamp when this page was updated since the user last saw it.
4441          *
4442          * @param User $user
4443          * @return string|null
4444          */
4445         public function getNotificationTimestamp( $user = null ) {
4446                 global $wgUser;
4447
4448                 // Assume current user if none given
4449                 if ( !$user ) {
4450                         $user = $wgUser;
4451                 }
4452                 // Check cache first
4453                 $uid = $user->getId();
4454                 if ( !$uid ) {
4455                         return false;
4456                 }
4457                 // avoid isset here, as it'll return false for null entries
4458                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4459                         return $this->mNotificationTimestamp[$uid];
4460                 }
4461                 // Don't cache too much!
4462                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4463                         $this->mNotificationTimestamp = array();
4464                 }
4465
4466                 $watchedItem = WatchedItem::fromUserTitle( $user, $this );
4467                 $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4468
4469                 return $this->mNotificationTimestamp[$uid];
4470         }
4471
4472         /**
4473          * Generate strings used for xml 'id' names in monobook tabs
4474          *
4475          * @param string $prepend Defaults to 'nstab-'
4476          * @return string XML 'id' name
4477          */
4478         public function getNamespaceKey( $prepend = 'nstab-' ) {
4479                 global $wgContLang;
4480                 // Gets the subject namespace if this title
4481                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4482                 // Checks if canonical namespace name exists for namespace
4483                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4484                         // Uses canonical namespace name
4485                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4486                 } else {
4487                         // Uses text of namespace
4488                         $namespaceKey = $this->getSubjectNsText();
4489                 }
4490                 // Makes namespace key lowercase
4491                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4492                 // Uses main
4493                 if ( $namespaceKey == '' ) {
4494                         $namespaceKey = 'main';
4495                 }
4496                 // Changes file to image for backwards compatibility
4497                 if ( $namespaceKey == 'file' ) {
4498                         $namespaceKey = 'image';
4499                 }
4500                 return $prepend . $namespaceKey;
4501         }
4502
4503         /**
4504          * Get all extant redirects to this Title
4505          *
4506          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4507          * @return Title[] Array of Title redirects to this title
4508          */
4509         public function getRedirectsHere( $ns = null ) {
4510                 $redirs = array();
4511
4512                 $dbr = wfGetDB( DB_SLAVE );
4513                 $where = array(
4514                         'rd_namespace' => $this->getNamespace(),
4515                         'rd_title' => $this->getDBkey(),
4516                         'rd_from = page_id'
4517                 );
4518                 if ( $this->isExternal() ) {
4519                         $where['rd_interwiki'] = $this->getInterwiki();
4520                 } else {
4521                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4522                 }
4523                 if ( !is_null( $ns ) ) {
4524                         $where['page_namespace'] = $ns;
4525                 }
4526
4527                 $res = $dbr->select(
4528                         array( 'redirect', 'page' ),
4529                         array( 'page_namespace', 'page_title' ),
4530                         $where,
4531                         __METHOD__
4532                 );
4533
4534                 foreach ( $res as $row ) {
4535                         $redirs[] = self::newFromRow( $row );
4536                 }
4537                 return $redirs;
4538         }
4539
4540         /**
4541          * Check if this Title is a valid redirect target
4542          *
4543          * @return bool
4544          */
4545         public function isValidRedirectTarget() {
4546                 global $wgInvalidRedirectTargets;
4547
4548                 if ( $this->isSpecialPage() ) {
4549                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4550                         if ( $this->isSpecial( 'Userlogout' ) ) {
4551                                 return false;
4552                         }
4553
4554                         foreach ( $wgInvalidRedirectTargets as $target ) {
4555                                 if ( $this->isSpecial( $target ) ) {
4556                                         return false;
4557                                 }
4558                         }
4559                 }
4560
4561                 return true;
4562         }
4563
4564         /**
4565          * Get a backlink cache object
4566          *
4567          * @return BacklinkCache
4568          */
4569         public function getBacklinkCache() {
4570                 return BacklinkCache::get( $this );
4571         }
4572
4573         /**
4574          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4575          *
4576          * @return bool
4577          */
4578         public function canUseNoindex() {
4579                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4580
4581                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4582                         ? $wgContentNamespaces
4583                         : $wgExemptFromUserRobotsControl;
4584
4585                 return !in_array( $this->mNamespace, $bannedNamespaces );
4586
4587         }
4588
4589         /**
4590          * Returns the raw sort key to be used for categories, with the specified
4591          * prefix.  This will be fed to Collation::getSortKey() to get a
4592          * binary sortkey that can be used for actual sorting.
4593          *
4594          * @param string $prefix The prefix to be used, specified using
4595          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4596          *   prefix.
4597          * @return string
4598          */
4599         public function getCategorySortkey( $prefix = '' ) {
4600                 $unprefixed = $this->getText();
4601
4602                 // Anything that uses this hook should only depend
4603                 // on the Title object passed in, and should probably
4604                 // tell the users to run updateCollations.php --force
4605                 // in order to re-sort existing category relations.
4606                 Hooks::run( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4607                 if ( $prefix !== '' ) {
4608                         # Separate with a line feed, so the unprefixed part is only used as
4609                         # a tiebreaker when two pages have the exact same prefix.
4610                         # In UCA, tab is the only character that can sort above LF
4611                         # so we strip both of them from the original prefix.
4612                         $prefix = strtr( $prefix, "\n\t", '  ' );
4613                         return "$prefix\n$unprefixed";
4614                 }
4615                 return $unprefixed;
4616         }
4617
4618         /**
4619          * Get the language in which the content of this page is written in
4620          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4621          * e.g. $wgLang (such as special pages, which are in the user language).
4622          *
4623          * @since 1.18
4624          * @return Language
4625          */
4626         public function getPageLanguage() {
4627                 global $wgLang, $wgLanguageCode;
4628                 if ( $this->isSpecialPage() ) {
4629                         // special pages are in the user language
4630                         return $wgLang;
4631                 }
4632
4633                 // Checking if DB language is set
4634                 if ( $this->mDbPageLanguage ) {
4635                         return wfGetLangObj( $this->mDbPageLanguage );
4636                 }
4637
4638                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4639                         // Note that this may depend on user settings, so the cache should
4640                         // be only per-request.
4641                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4642                         // content to determine the page language!
4643                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4644                         // tests.
4645                         $contentHandler = ContentHandler::getForTitle( $this );
4646                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4647                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4648                 } else {
4649                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4650                 }
4651
4652                 return $langObj;
4653         }
4654
4655         /**
4656          * Get the language in which the content of this page is written when
4657          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4658          * e.g. $wgLang (such as special pages, which are in the user language).
4659          *
4660          * @since 1.20
4661          * @return Language
4662          */
4663         public function getPageViewLanguage() {
4664                 global $wgLang;
4665
4666                 if ( $this->isSpecialPage() ) {
4667                         // If the user chooses a variant, the content is actually
4668                         // in a language whose code is the variant code.
4669                         $variant = $wgLang->getPreferredVariant();
4670                         if ( $wgLang->getCode() !== $variant ) {
4671                                 return Language::factory( $variant );
4672                         }
4673
4674                         return $wgLang;
4675                 }
4676
4677                 // @note Can't be cached persistently, depends on user settings.
4678                 // @note ContentHandler::getPageViewLanguage() may need to load the
4679                 //   content to determine the page language!
4680                 $contentHandler = ContentHandler::getForTitle( $this );
4681                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4682                 return $pageLang;
4683         }
4684
4685         /**
4686          * Get a list of rendered edit notices for this page.
4687          *
4688          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4689          * they will already be wrapped in paragraphs.
4690          *
4691          * @since 1.21
4692          * @param int $oldid Revision ID that's being edited
4693          * @return array
4694          */
4695         public function getEditNotices( $oldid = 0 ) {
4696                 $notices = array();
4697
4698                 // Optional notice for the entire namespace
4699                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4700                 $msg = wfMessage( $editnotice_ns );
4701                 if ( $msg->exists() ) {
4702                         $html = $msg->parseAsBlock();
4703                         // Edit notices may have complex logic, but output nothing (T91715)
4704                         if ( trim( $html ) !== '' ) {
4705                                 $notices[$editnotice_ns] = Html::rawElement(
4706                                         'div',
4707                                         array( 'class' => array(
4708                                                 'mw-editnotice',
4709                                                 'mw-editnotice-namespace',
4710                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4711                                         ) ),
4712                                         $html
4713                                 );
4714                         }
4715                 }
4716
4717                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4718                         // Optional notice for page itself and any parent page
4719                         $parts = explode( '/', $this->getDBkey() );
4720                         $editnotice_base = $editnotice_ns;
4721                         while ( count( $parts ) > 0 ) {
4722                                 $editnotice_base .= '-' . array_shift( $parts );
4723                                 $msg = wfMessage( $editnotice_base );
4724                                 if ( $msg->exists() ) {
4725                                         $html = $msg->parseAsBlock();
4726                                         if ( trim( $html ) !== '' ) {
4727                                                 $notices[$editnotice_base] = Html::rawElement(
4728                                                         'div',
4729                                                         array( 'class' => array(
4730                                                                 'mw-editnotice',
4731                                                                 'mw-editnotice-base',
4732                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4733                                                         ) ),
4734                                                         $html
4735                                                 );
4736                                         }
4737                                 }
4738                         }
4739                 } else {
4740                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4741                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4742                         $msg = wfMessage( $editnoticeText );
4743                         if ( $msg->exists() ) {
4744                                 $html = $msg->parseAsBlock();
4745                                 if ( trim( $html ) !== '' ) {
4746                                         $notices[$editnoticeText] = Html::rawElement(
4747                                                 'div',
4748                                                 array( 'class' => array(
4749                                                         'mw-editnotice',
4750                                                         'mw-editnotice-page',
4751                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4752                                                 ) ),
4753                                                 $html
4754                                         );
4755                                 }
4756                         }
4757                 }
4758
4759                 Hooks::run( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4760                 return $notices;
4761         }
4762
4763         /**
4764          * @return array
4765          */
4766         public function __sleep() {
4767                 return array(
4768                         'mNamespace',
4769                         'mDbkeyform',
4770                         'mFragment',
4771                         'mInterwiki',
4772                         'mLocalInterwiki',
4773                         'mUserCaseDBKey',
4774                         'mDefaultNamespace',
4775                 );
4776         }
4777
4778         public function __wakeup() {
4779                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4780                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4781                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4782         }
4783
4784 }