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( __METHOD__ . ': $text must be a string. This will throw an InvalidArgumentException in future.', 2 );
 270                 }
 271
 272                 try {
 273                         return Title::newFromTextThrow( $text, $defaultNamespace );
 274                 } catch ( MalformedTitleException $ex ) {
 275                         return null;
 276                 }
 277         }
 278
 279         /**
 280          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 281          * rather than returning null.
 282          *
 283          * The exception subclasses encode detailed information about why the title is invalid.
 284          *
 285          * @see Title::newFromText
 286          *
 287          * @since 1.25
 288          * @param string $text Title text to check
 289          * @param int $defaultNamespace
 290          * @throws MalformedTitleException If the title is invalid
 291          * @return Title
 292          */
 293         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 294                 if ( is_object( $text ) ) {
 295                         throw new MWException( 'Title::newFromTextThrow given an object' );
 296                 }
 297
 298                 $cache = self::getTitleCache();
 299
 300                 /**
 301                  * Wiki pages often contain multiple links to the same page.
 302                  * Title normalization and parsing can become expensive on
 303                  * pages with many links, so we can save a little time by
 304                  * caching them.
 305                  *
 306                  * In theory these are value objects and won't get changed...
 307                  */
 308                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 309                         return $cache->get( $text );
 310                 }
 311
 312                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 313                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 314
 315                 $t = new Title();
 316                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 317                 $t->mDefaultNamespace = intval( $defaultNamespace );
 318
 319                 $t->secureAndSplit();
 320                 if ( $defaultNamespace == NS_MAIN ) {
 321                         $cache->set( $text, $t );
 322                 }
 323                 return $t;
 324         }
 325
 326         /**
 327          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 328          *
 329          * Example of wrong and broken code:
 330          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 331          *
 332          * Example of right code:
 333          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 334          *
 335          * Create a new Title from URL-encoded text. Ensures that
 336          * the given title's length does not exceed the maximum.
 337          *
 338          * @param string $url The title, as might be taken from a URL
 339          * @return Title|null The new object, or null on an error
 340          */
 341         public static function newFromURL( $url ) {
 342                 $t = new Title();
 343
 344                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 345                 # but some URLs used it as a space replacement and they still come
 346                 # from some external search tools.
 347                 if ( strpos( self::legalChars(), '+' ) === false ) {
 348                         $url = strtr( $url, '+', ' ' );
 349                 }
 350
 351                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 352
 353                 try {
 354                         $t->secureAndSplit();
 355                         return $t;
 356                 } catch ( MalformedTitleException $ex ) {
 357                         return null;
 358                 }
 359         }
 360
 361         /**
 362          * @return MapCacheLRU
 363          */
 364         private static function getTitleCache() {
 365                 if ( self::$titleCache == null ) {
 366                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 367                 }
 368                 return self::$titleCache;
 369         }
 370
 371         /**
 372          * Returns a list of fields that are to be selected for initializing Title
 373          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 374          * whether to include page_content_model.
 375          *
 376          * @return array
 377          */
 378         protected static function getSelectFields() {
 379                 global $wgContentHandlerUseDB;
 380
 381                 $fields = array(
 382                         'page_namespace', 'page_title', 'page_id',
 383                         'page_len', 'page_is_redirect', 'page_latest',
 384                 );
 385
 386                 if ( $wgContentHandlerUseDB ) {
 387                         $fields[] = 'page_content_model';
 388                 }
 389
 390                 return $fields;
 391         }
 392
 393         /**
 394          * Create a new Title from an article ID
 395          *
 396          * @param int $id The page_id corresponding to the Title to create
 397          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 398          * @return Title|null The new object, or null on an error
 399          */
 400         public static function newFromID( $id, $flags = 0 ) {
 401                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 402                 $row = $db->selectRow(
 403                         'page',
 404                         self::getSelectFields(),
 405                         array( 'page_id' => $id ),
 406                         __METHOD__
 407                 );
 408                 if ( $row !== false ) {
 409                         $title = Title::newFromRow( $row );
 410                 } else {
 411                         $title = null;
 412                 }
 413                 return $title;
 414         }
 415
 416         /**
 417          * Make an array of titles from an array of IDs
 418          *
 419          * @param int[] $ids Array of IDs
 420          * @return Title[] Array of Titles
 421          */
 422         public static function newFromIDs( $ids ) {
 423                 if ( !count( $ids ) ) {
 424                         return array();
 425                 }
 426                 $dbr = wfGetDB( DB_SLAVE );
 427
 428                 $res = $dbr->select(
 429                         'page',
 430                         self::getSelectFields(),
 431                         array( 'page_id' => $ids ),
 432                         __METHOD__
 433                 );
 434
 435                 $titles = array();
 436                 foreach ( $res as $row ) {
 437                         $titles[] = Title::newFromRow( $row );
 438                 }
 439                 return $titles;
 440         }
 441
 442         /**
 443          * Make a Title object from a DB row
 444          *
 445          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 446          * @return Title Corresponding Title
 447          */
 448         public static function newFromRow( $row ) {
 449                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 450                 $t->loadFromRow( $row );
 451                 return $t;
 452         }
 453
 454         /**
 455          * Load Title object fields from a DB row.
 456          * If false is given, the title will be treated as non-existing.
 457          *
 458          * @param stdClass|bool $row Database row
 459          */
 460         public function loadFromRow( $row ) {
 461                 if ( $row ) { // page found
 462                         if ( isset( $row->page_id ) ) {
 463                                 $this->mArticleID = (int)$row->page_id;
 464                         }
 465                         if ( isset( $row->page_len ) ) {
 466                                 $this->mLength = (int)$row->page_len;
 467                         }
 468                         if ( isset( $row->page_is_redirect ) ) {
 469                                 $this->mRedirect = (bool)$row->page_is_redirect;
 470                         }
 471                         if ( isset( $row->page_latest ) ) {
 472                                 $this->mLatestID = (int)$row->page_latest;
 473                         }
 474                         if ( isset( $row->page_content_model ) ) {
 475                                 $this->mContentModel = strval( $row->page_content_model );
 476                         } else {
 477                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 478                         }
 479                         if ( isset( $row->page_lang ) ) {
 480                                 $this->mDbPageLanguage = (string)$row->page_lang;
 481                         }
 482                         if ( isset( $row->page_restrictions ) ) {
 483                                 $this->mOldRestrictions = $row->page_restrictions;
 484                         }
 485                 } else { // page not found
 486                         $this->mArticleID = 0;
 487                         $this->mLength = 0;
 488                         $this->mRedirect = false;
 489                         $this->mLatestID = 0;
 490                         $this->mContentModel = false; # initialized lazily in getContentModel()
 491                 }
 492         }
 493
 494         /**
 495          * Create a new Title from a namespace index and a DB key.
 496          * It's assumed that $ns and $title are *valid*, for instance when
 497          * they came directly from the database or a special page name.
 498          * For convenience, spaces are converted to underscores so that
 499          * eg user_text fields can be used directly.
 500          *
 501          * @param int $ns The namespace of the article
 502          * @param string $title The unprefixed database key form
 503          * @param string $fragment The link fragment (after the "#")
 504          * @param string $interwiki The interwiki prefix
 505          * @return Title The new object
 506          */
 507         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 508                 $t = new Title();
 509                 $t->mInterwiki = $interwiki;
 510                 $t->mFragment = $fragment;
 511                 $t->mNamespace = $ns = intval( $ns );
 512                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 513                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 514                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 515                 $t->mTextform = strtr( $title, '_', ' ' );
 516                 $t->mContentModel = false; # initialized lazily in getContentModel()
 517                 return $t;
 518         }
 519
 520         /**
 521          * Create a new Title from a namespace index and a DB key.
 522          * The parameters will be checked for validity, which is a bit slower
 523          * than makeTitle() but safer for user-provided data.
 524          *
 525          * @param int $ns The namespace of the article
 526          * @param string $title Database key form
 527          * @param string $fragment The link fragment (after the "#")
 528          * @param string $interwiki Interwiki prefix
 529          * @return Title The new object, or null on an error
 530          */
 531         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 532                 if ( !MWNamespace::exists( $ns ) ) {
 533                         return null;
 534                 }
 535
 536                 $t = new Title();
 537                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 538
 539                 try {
 540                         $t->secureAndSplit();
 541                         return $t;
 542                 } catch ( MalformedTitleException $ex ) {
 543                         return null;
 544                 }
 545         }
 546
 547         /**
 548          * Create a new Title for the Main Page
 549          *
 550          * @return Title The new object
 551          */
 552         public static function newMainPage() {
 553                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 554                 // Don't give fatal errors if the message is broken
 555                 if ( !$title ) {
 556                         $title = Title::newFromText( 'Main Page' );
 557                 }
 558                 return $title;
 559         }
 560
 561         /**
 562          * Extract a redirect destination from a string and return the
 563          * Title, or null if the text doesn't contain a valid redirect
 564          * This will only return the very next target, useful for
 565          * the redirect table and other checks that don't need full recursion
 566          *
 567          * @param string $text Text with possible redirect
 568          * @return Title The corresponding Title
 569          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 570          */
 571         public static function newFromRedirect( $text ) {
 572                 ContentHandler::deprecated( __METHOD__, '1.21' );
 573
 574                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 575                 return $content->getRedirectTarget();
 576         }
 577
 578         /**
 579          * Extract a redirect destination from a string and return the
 580          * Title, or null if the text doesn't contain a valid redirect
 581          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 582          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 583          *
 584          * @param string $text Text with possible redirect
 585          * @return Title
 586          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 587          */
 588         public static function newFromRedirectRecurse( $text ) {
 589                 ContentHandler::deprecated( __METHOD__, '1.21' );
 590
 591                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 592                 return $content->getUltimateRedirectTarget();
 593         }
 594
 595         /**
 596          * Extract a redirect destination from a string and return an
 597          * array of Titles, or null if the text doesn't contain a valid redirect
 598          * The last element in the array is the final destination after all redirects
 599          * have been resolved (up to $wgMaxRedirects times)
 600          *
 601          * @param string $text Text with possible redirect
 602          * @return Title[] Array of Titles, with the destination last
 603          * @deprecated since 1.21, use Content::getRedirectChain instead.
 604          */
 605         public static function newFromRedirectArray( $text ) {
 606                 ContentHandler::deprecated( __METHOD__, '1.21' );
 607
 608                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 609                 return $content->getRedirectChain();
 610         }
 611
 612         /**
 613          * Get the prefixed DB key associated with an ID
 614          *
 615          * @param int $id The page_id of the article
 616          * @return Title|null An object representing the article, or null if no such article was found
 617          */
 618         public static function nameOf( $id ) {
 619                 $dbr = wfGetDB( DB_SLAVE );
 620
 621                 $s = $dbr->selectRow(
 622                         'page',
 623                         array( 'page_namespace', 'page_title' ),
 624                         array( 'page_id' => $id ),
 625                         __METHOD__
 626                 );
 627                 if ( $s === false ) {
 628                         return null;
 629                 }
 630
 631                 $n = self::makeName( $s->page_namespace, $s->page_title );
 632                 return $n;
 633         }
 634
 635         /**
 636          * Get a regex character class describing the legal characters in a link
 637          *
 638          * @return string The list of characters, not delimited
 639          */
 640         public static function legalChars() {
 641                 global $wgLegalTitleChars;
 642                 return $wgLegalTitleChars;
 643         }
 644
 645         /**
 646          * Returns a simple regex that will match on characters and sequences invalid in titles.
 647          * Note that this doesn't pick up many things that could be wrong with titles, but that
 648          * replacing this regex with something valid will make many titles valid.
 649          *
 650          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 651          *
 652          * @return string Regex string
 653          */
 654         static function getTitleInvalidRegex() {
 655                 wfDeprecated( __METHOD__, '1.25' );
 656                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 657         }
 658
 659         /**
 660          * Utility method for converting a character sequence from bytes to Unicode.
 661          *
 662          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 663          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 664          *
 665          * @param string $byteClass
 666          * @return string
 667          */
 668         public static function convertByteClassToUnicodeClass( $byteClass ) {
 669                 $length = strlen( $byteClass );
 670                 // Input token queue
 671                 $x0 = $x1 = $x2 = '';
 672                 // Decoded queue
 673                 $d0 = $d1 = $d2 = '';
 674                 // Decoded integer codepoints
 675                 $ord0 = $ord1 = $ord2 = 0;
 676                 // Re-encoded queue
 677                 $r0 = $r1 = $r2 = '';
 678                 // Output
 679                 $out = '';
 680                 // Flags
 681                 $allowUnicode = false;
 682                 for ( $pos = 0; $pos < $length; $pos++ ) {
 683                         // Shift the queues down
 684                         $x2 = $x1;
 685                         $x1 = $x0;
 686                         $d2 = $d1;
 687                         $d1 = $d0;
 688                         $ord2 = $ord1;
 689                         $ord1 = $ord0;
 690                         $r2 = $r1;
 691                         $r1 = $r0;
 692                         // Load the current input token and decoded values
 693                         $inChar = $byteClass[$pos];
 694                         if ( $inChar == '\\' ) {
 695                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 696                                         $x0 = $inChar . $m[0];
 697                                         $d0 = chr( hexdec( $m[1] ) );
 698                                         $pos += strlen( $m[0] );
 699                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 700                                         $x0 = $inChar . $m[0];
 701                                         $d0 = chr( octdec( $m[0] ) );
 702                                         $pos += strlen( $m[0] );
 703                                 } elseif ( $pos + 1 >= $length ) {
 704                                         $x0 = $d0 = '\\';
 705                                 } else {
 706                                         $d0 = $byteClass[$pos + 1];
 707                                         $x0 = $inChar . $d0;
 708                                         $pos += 1;
 709                                 }
 710                         } else {
 711                                 $x0 = $d0 = $inChar;
 712                         }
 713                         $ord0 = ord( $d0 );
 714                         // Load the current re-encoded value
 715                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 716                                 $r0 = sprintf( '\x%02x', $ord0 );
 717                         } elseif ( $ord0 >= 0x80 ) {
 718                                 // Allow unicode if a single high-bit character appears
 719                                 $r0 = sprintf( '\x%02x', $ord0 );
 720                                 $allowUnicode = true;
 721                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 722                                 $r0 = '\\' . $d0;
 723                         } else {
 724                                 $r0 = $d0;
 725                         }
 726                         // Do the output
 727                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 728                                 // Range
 729                                 if ( $ord2 > $ord0 ) {
 730                                         // Empty range
 731                                 } elseif ( $ord0 >= 0x80 ) {
 732                                         // Unicode range
 733                                         $allowUnicode = true;
 734                                         if ( $ord2 < 0x80 ) {
 735                                                 // Keep the non-unicode section of the range
 736                                                 $out .= "$r2-\\x7F";
 737                                         }
 738                                 } else {
 739                                         // Normal range
 740                                         $out .= "$r2-$r0";
 741                                 }
 742                                 // Reset state to the initial value
 743                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 744                         } elseif ( $ord2 < 0x80 ) {
 745                                 // ASCII character
 746                                 $out .= $r2;
 747                         }
 748                 }
 749                 if ( $ord1 < 0x80 ) {
 750                         $out .= $r1;
 751                 }
 752                 if ( $ord0 < 0x80 ) {
 753                         $out .= $r0;
 754                 }
 755                 if ( $allowUnicode ) {
 756                         $out .= '\u0080-\uFFFF';
 757                 }
 758                 return $out;
 759         }
 760
 761         /**
 762          * Make a prefixed DB key from a DB key and a namespace index
 763          *
 764          * @param int $ns Numerical representation of the namespace
 765          * @param string $title The DB key form the title
 766          * @param string $fragment The link fragment (after the "#")
 767          * @param string $interwiki The interwiki prefix
 768          * @param bool $canoncialNamespace If true, use the canonical name for
 769          *   $ns instead of the localized version.
 770          * @return string The prefixed form of the title
 771          */
 772         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 773                 $canoncialNamespace = false
 774         ) {
 775                 global $wgContLang;
 776
 777                 if ( $canoncialNamespace ) {
 778                         $namespace = MWNamespace::getCanonicalName( $ns );
 779                 } else {
 780                         $namespace = $wgContLang->getNsText( $ns );
 781                 }
 782                 $name = $namespace == '' ? $title : "$namespace:$title";
 783                 if ( strval( $interwiki ) != '' ) {
 784                         $name = "$interwiki:$name";
 785                 }
 786                 if ( strval( $fragment ) != '' ) {
 787                         $name .= '#' . $fragment;
 788                 }
 789                 return $name;
 790         }
 791
 792         /**
 793          * Escape a text fragment, say from a link, for a URL
 794          *
 795          * @param string $fragment Containing a URL or link fragment (after the "#")
 796          * @return string Escaped string
 797          */
 798         static function escapeFragmentForURL( $fragment ) {
 799                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 800                 # fragments appear not to work in IE (at least up to 7) or in at least
 801                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 802                 # to care if they aren't encoded.
 803                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 804         }
 805
 806         /**
 807          * Callback for usort() to do title sorts by (namespace, title)
 808          *
 809          * @param Title $a
 810          * @param Title $b
 811          *
 812          * @return int Result of string comparison, or namespace comparison
 813          */
 814         public static function compare( $a, $b ) {
 815                 if ( $a->getNamespace() == $b->getNamespace() ) {
 816                         return strcmp( $a->getText(), $b->getText() );
 817                 } else {
 818                         return $a->getNamespace() - $b->getNamespace();
 819                 }
 820         }
 821
 822         /**
 823          * Determine whether the object refers to a page within
 824          * this project (either this wiki or a wiki with a local
 825          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 826          *
 827          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 828          */
 829         public function isLocal() {
 830                 if ( $this->isExternal() ) {
 831                         $iw = Interwiki::fetch( $this->mInterwiki );
 832                         if ( $iw ) {
 833                                 return $iw->isLocal();
 834                         }
 835                 }
 836                 return true;
 837         }
 838
 839         /**
 840          * Is this Title interwiki?
 841          *
 842          * @return bool
 843          */
 844         public function isExternal() {
 845                 return $this->mInterwiki !== '';
 846         }
 847
 848         /**
 849          * Get the interwiki prefix
 850          *
 851          * Use Title::isExternal to check if a interwiki is set
 852          *
 853          * @return string Interwiki prefix
 854          */
 855         public function getInterwiki() {
 856                 return $this->mInterwiki;
 857         }
 858
 859         /**
 860          * Was this a local interwiki link?
 861          *
 862          * @return bool
 863          */
 864         public function wasLocalInterwiki() {
 865                 return $this->mLocalInterwiki;
 866         }
 867
 868         /**
 869          * Determine whether the object refers to a page within
 870          * this project and is transcludable.
 871          *
 872          * @return bool True if this is transcludable
 873          */
 874         public function isTrans() {
 875                 if ( !$this->isExternal() ) {
 876                         return false;
 877                 }
 878
 879                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 880         }
 881
 882         /**
 883          * Returns the DB name of the distant wiki which owns the object.
 884          *
 885          * @return string The DB name
 886          */
 887         public function getTransWikiID() {
 888                 if ( !$this->isExternal() ) {
 889                         return false;
 890                 }
 891
 892                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 893         }
 894
 895         /**
 896          * Get a TitleValue object representing this Title.
 897          *
 898          * @note Not all valid Titles have a corresponding valid TitleValue
 899          * (e.g. TitleValues cannot represent page-local links that have a
 900          * fragment but no title text).
 901          *
 902          * @return TitleValue|null
 903          */
 904         public function getTitleValue() {
 905                 if ( $this->mTitleValue === null ) {
 906                         try {
 907                                 $this->mTitleValue = new TitleValue(
 908                                         $this->getNamespace(),
 909                                         $this->getDBkey(),
 910                                         $this->getFragment() );
 911                         } catch ( InvalidArgumentException $ex ) {
 912                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 913                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 914                         }
 915                 }
 916
 917                 return $this->mTitleValue;
 918         }
 919
 920         /**
 921          * Get the text form (spaces not underscores) of the main part
 922          *
 923          * @return string Main part of the title
 924          */
 925         public function getText() {
 926                 return $this->mTextform;
 927         }
 928
 929         /**
 930          * Get the URL-encoded form of the main part
 931          *
 932          * @return string Main part of the title, URL-encoded
 933          */
 934         public function getPartialURL() {
 935                 return $this->mUrlform;
 936         }
 937
 938         /**
 939          * Get the main part with underscores
 940          *
 941          * @return string Main part of the title, with underscores
 942          */
 943         public function getDBkey() {
 944                 return $this->mDbkeyform;
 945         }
 946
 947         /**
 948          * Get the DB key with the initial letter case as specified by the user
 949          *
 950          * @return string DB key
 951          */
 952         function getUserCaseDBKey() {
 953                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 954                         return $this->mUserCaseDBKey;
 955                 } else {
 956                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 957                         return $this->mDbkeyform;
 958                 }
 959         }
 960
 961         /**
 962          * Get the namespace index, i.e. one of the NS_xxxx constants.
 963          *
 964          * @return int Namespace index
 965          */
 966         public function getNamespace() {
 967                 return $this->mNamespace;
 968         }
 969
 970         /**
 971          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 972          *
 973          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 974          * @return string Content model id
 975          */
 976         public function getContentModel( $flags = 0 ) {
 977                 if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 978                         $linkCache = LinkCache::singleton();
 979                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 980                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 981                 }
 982
 983                 if ( !$this->mContentModel ) {
 984                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 985                 }
 986
 987                 return $this->mContentModel;
 988         }
 989
 990         /**
 991          * Convenience method for checking a title's content model name
 992          *
 993          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 994          * @return bool True if $this->getContentModel() == $id
 995          */
 996         public function hasContentModel( $id ) {
 997                 return $this->getContentModel() == $id;
 998         }
 999
1000         /**
1001          * Get the namespace text
1002          *
1003          * @return string Namespace text
1004          */
1005         public function getNsText() {
1006                 if ( $this->isExternal() ) {
1007                         // This probably shouldn't even happen. ohh man, oh yuck.
1008                         // But for interwiki transclusion it sometimes does.
1009                         // Shit. Shit shit shit.
1010                         //
1011                         // Use the canonical namespaces if possible to try to
1012                         // resolve a foreign namespace.
1013                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1014                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1015                         }
1016                 }
1017
1018                 try {
1019                         $formatter = self::getTitleFormatter();
1020                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1021                 } catch ( InvalidArgumentException $ex ) {
1022                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1023                         return false;
1024                 }
1025         }
1026
1027         /**
1028          * Get the namespace text of the subject (rather than talk) page
1029          *
1030          * @return string Namespace text
1031          */
1032         public function getSubjectNsText() {
1033                 global $wgContLang;
1034                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1035         }
1036
1037         /**
1038          * Get the namespace text of the talk page
1039          *
1040          * @return string Namespace text
1041          */
1042         public function getTalkNsText() {
1043                 global $wgContLang;
1044                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1045         }
1046
1047         /**
1048          * Could this title have a corresponding talk page?
1049          *
1050          * @return bool
1051          */
1052         public function canTalk() {
1053                 return MWNamespace::canTalk( $this->mNamespace );
1054         }
1055
1056         /**
1057          * Is this in a namespace that allows actual pages?
1058          *
1059          * @return bool
1060          */
1061         public function canExist() {
1062                 return $this->mNamespace >= NS_MAIN;
1063         }
1064
1065         /**
1066          * Can this title be added to a user's watchlist?
1067          *
1068          * @return bool
1069          */
1070         public function isWatchable() {
1071                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1072         }
1073
1074         /**
1075          * Returns true if this is a special page.
1076          *
1077          * @return bool
1078          */
1079         public function isSpecialPage() {
1080                 return $this->getNamespace() == NS_SPECIAL;
1081         }
1082
1083         /**
1084          * Returns true if this title resolves to the named special page
1085          *
1086          * @param string $name The special page name
1087          * @return bool
1088          */
1089         public function isSpecial( $name ) {
1090                 if ( $this->isSpecialPage() ) {
1091                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1092                         if ( $name == $thisName ) {
1093                                 return true;
1094                         }
1095                 }
1096                 return false;
1097         }
1098
1099         /**
1100          * If the Title refers to a special page alias which is not the local default, resolve
1101          * the alias, and localise the name as necessary.  Otherwise, return $this
1102          *
1103          * @return Title
1104          */
1105         public function fixSpecialName() {
1106                 if ( $this->isSpecialPage() ) {
1107                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1108                         if ( $canonicalName ) {
1109                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1110                                 if ( $localName != $this->mDbkeyform ) {
1111                                         return Title::makeTitle( NS_SPECIAL, $localName );
1112                                 }
1113                         }
1114                 }
1115                 return $this;
1116         }
1117
1118         /**
1119          * Returns true if the title is inside the specified namespace.
1120          *
1121          * Please make use of this instead of comparing to getNamespace()
1122          * This function is much more resistant to changes we may make
1123          * to namespaces than code that makes direct comparisons.
1124          * @param int $ns The namespace
1125          * @return bool
1126          * @since 1.19
1127          */
1128         public function inNamespace( $ns ) {
1129                 return MWNamespace::equals( $this->getNamespace(), $ns );
1130         }
1131
1132         /**
1133          * Returns true if the title is inside one of the specified namespaces.
1134          *
1135          * @param int $namespaces,... The namespaces to check for
1136          * @return bool
1137          * @since 1.19
1138          */
1139         public function inNamespaces( /* ... */ ) {
1140                 $namespaces = func_get_args();
1141                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1142                         $namespaces = $namespaces[0];
1143                 }
1144
1145                 foreach ( $namespaces as $ns ) {
1146                         if ( $this->inNamespace( $ns ) ) {
1147                                 return true;
1148                         }
1149                 }
1150
1151                 return false;
1152         }
1153
1154         /**
1155          * Returns true if the title has the same subject namespace as the
1156          * namespace specified.
1157          * For example this method will take NS_USER and return true if namespace
1158          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1159          * as their subject namespace.
1160          *
1161          * This is MUCH simpler than individually testing for equivalence
1162          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1163          * @since 1.19
1164          * @param int $ns
1165          * @return bool
1166          */
1167         public function hasSubjectNamespace( $ns ) {
1168                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1169         }
1170
1171         /**
1172          * Is this Title in a namespace which contains content?
1173          * In other words, is this a content page, for the purposes of calculating
1174          * statistics, etc?
1175          *
1176          * @return bool
1177          */
1178         public function isContentPage() {
1179                 return MWNamespace::isContent( $this->getNamespace() );
1180         }
1181
1182         /**
1183          * Would anybody with sufficient privileges be able to move this page?
1184          * Some pages just aren't movable.
1185          *
1186          * @return bool
1187          */
1188         public function isMovable() {
1189                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1190                         // Interwiki title or immovable namespace. Hooks don't get to override here
1191                         return false;
1192                 }
1193
1194                 $result = true;
1195                 Hooks::run( 'TitleIsMovable', array( $this, &$result ) );
1196                 return $result;
1197         }
1198
1199         /**
1200          * Is this the mainpage?
1201          * @note Title::newFromText seems to be sufficiently optimized by the title
1202          * cache that we don't need to over-optimize by doing direct comparisons and
1203          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1204          * ends up reporting something differently than $title->isMainPage();
1205          *
1206          * @since 1.18
1207          * @return bool
1208          */
1209         public function isMainPage() {
1210                 return $this->equals( Title::newMainPage() );
1211         }
1212
1213         /**
1214          * Is this a subpage?
1215          *
1216          * @return bool
1217          */
1218         public function isSubpage() {
1219                 return MWNamespace::hasSubpages( $this->mNamespace )
1220                         ? strpos( $this->getText(), '/' ) !== false
1221                         : false;
1222         }
1223
1224         /**
1225          * Is this a conversion table for the LanguageConverter?
1226          *
1227          * @return bool
1228          */
1229         public function isConversionTable() {
1230                 // @todo ConversionTable should become a separate content model.
1231
1232                 return $this->getNamespace() == NS_MEDIAWIKI &&
1233                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1234         }
1235
1236         /**
1237          * Does that page contain wikitext, or it is JS, CSS or whatever?
1238          *
1239          * @return bool
1240          */
1241         public function isWikitextPage() {
1242                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1243         }
1244
1245         /**
1246          * Could this page contain custom CSS or JavaScript for the global UI.
1247          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1248          * or CONTENT_MODEL_JAVASCRIPT.
1249          *
1250          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1251          * for that!
1252          *
1253          * Note that this method should not return true for pages that contain and
1254          * show "inactive" CSS or JS.
1255          *
1256          * @return bool
1257          */
1258         public function isCssOrJsPage() {
1259                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1260                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1261                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1262
1263                 # @note This hook is also called in ContentHandler::getDefaultModel.
1264                 #   It's called here again to make sure hook functions can force this
1265                 #   method to return true even outside the MediaWiki namespace.
1266
1267                 Hooks::run( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ), '1.25' );
1268
1269                 return $isCssOrJsPage;
1270         }
1271
1272         /**
1273          * Is this a .css or .js subpage of a user page?
1274          * @return bool
1275          */
1276         public function isCssJsSubpage() {
1277                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1278                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1279                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1280         }
1281
1282         /**
1283          * Trim down a .css or .js subpage title to get the corresponding skin name
1284          *
1285          * @return string Containing skin name from .css or .js subpage title
1286          */
1287         public function getSkinFromCssJsSubpage() {
1288                 $subpage = explode( '/', $this->mTextform );
1289                 $subpage = $subpage[count( $subpage ) - 1];
1290                 $lastdot = strrpos( $subpage, '.' );
1291                 if ( $lastdot === false ) {
1292                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1293                 }
1294                 return substr( $subpage, 0, $lastdot );
1295         }
1296
1297         /**
1298          * Is this a .css subpage of a user page?
1299          *
1300          * @return bool
1301          */
1302         public function isCssSubpage() {
1303                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1304                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1305         }
1306
1307         /**
1308          * Is this a .js subpage of a user page?
1309          *
1310          * @return bool
1311          */
1312         public function isJsSubpage() {
1313                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1314                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1315         }
1316
1317         /**
1318          * Is this a talk page of some sort?
1319          *
1320          * @return bool
1321          */
1322         public function isTalkPage() {
1323                 return MWNamespace::isTalk( $this->getNamespace() );
1324         }
1325
1326         /**
1327          * Get a Title object associated with the talk page of this article
1328          *
1329          * @return Title The object for the talk page
1330          */
1331         public function getTalkPage() {
1332                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1333         }
1334
1335         /**
1336          * Get a title object associated with the subject page of this
1337          * talk page
1338          *
1339          * @return Title The object for the subject page
1340          */
1341         public function getSubjectPage() {
1342                 // Is this the same title?
1343                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1344                 if ( $this->getNamespace() == $subjectNS ) {
1345                         return $this;
1346                 }
1347                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1348         }
1349
1350         /**
1351          * Get the other title for this page, if this is a subject page
1352          * get the talk page, if it is a subject page get the talk page
1353          *
1354          * @since 1.25
1355          * @throws MWException
1356          * @return Title
1357          */
1358         public function getOtherPage() {
1359                 if ( $this->isSpecialPage() ) {
1360                         throw new MWException( 'Special pages cannot have other pages' );
1361                 }
1362                 if ( $this->isTalkPage() ) {
1363                         return $this->getSubjectPage();
1364                 } else {
1365                         return $this->getTalkPage();
1366                 }
1367         }
1368
1369         /**
1370          * Get the default namespace index, for when there is no namespace
1371          *
1372          * @return int Default namespace index
1373          */
1374         public function getDefaultNamespace() {
1375                 return $this->mDefaultNamespace;
1376         }
1377
1378         /**
1379          * Get the Title fragment (i.e.\ the bit after the #) in text form
1380          *
1381          * Use Title::hasFragment to check for a fragment
1382          *
1383          * @return string Title fragment
1384          */
1385         public function getFragment() {
1386                 return $this->mFragment;
1387         }
1388
1389         /**
1390          * Check if a Title fragment is set
1391          *
1392          * @return bool
1393          * @since 1.23
1394          */
1395         public function hasFragment() {
1396                 return $this->mFragment !== '';
1397         }
1398
1399         /**
1400          * Get the fragment in URL form, including the "#" character if there is one
1401          * @return string Fragment in URL form
1402          */
1403         public function getFragmentForURL() {
1404                 if ( !$this->hasFragment() ) {
1405                         return '';
1406                 } else {
1407                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1408                 }
1409         }
1410
1411         /**
1412          * Set the fragment for this title. Removes the first character from the
1413          * specified fragment before setting, so it assumes you're passing it with
1414          * an initial "#".
1415          *
1416          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1417          * Still in active use privately.
1418          *
1419          * @param string $fragment Text
1420          */
1421         public function setFragment( $fragment ) {
1422                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1423         }
1424
1425         /**
1426          * Prefix some arbitrary text with the namespace or interwiki prefix
1427          * of this object
1428          *
1429          * @param string $name The text
1430          * @return string The prefixed text
1431          */
1432         private function prefix( $name ) {
1433                 $p = '';
1434                 if ( $this->isExternal() ) {
1435                         $p = $this->mInterwiki . ':';
1436                 }
1437
1438                 if ( 0 != $this->mNamespace ) {
1439                         $p .= $this->getNsText() . ':';
1440                 }
1441                 return $p . $name;
1442         }
1443
1444         /**
1445          * Get the prefixed database key form
1446          *
1447          * @return string The prefixed title, with underscores and
1448          *  any interwiki and namespace prefixes
1449          */
1450         public function getPrefixedDBkey() {
1451                 $s = $this->prefix( $this->mDbkeyform );
1452                 $s = strtr( $s, ' ', '_' );
1453                 return $s;
1454         }
1455
1456         /**
1457          * Get the prefixed title with spaces.
1458          * This is the form usually used for display
1459          *
1460          * @return string The prefixed title, with spaces
1461          */
1462         public function getPrefixedText() {
1463                 if ( $this->mPrefixedText === null ) {
1464                         $s = $this->prefix( $this->mTextform );
1465                         $s = strtr( $s, '_', ' ' );
1466                         $this->mPrefixedText = $s;
1467                 }
1468                 return $this->mPrefixedText;
1469         }
1470
1471         /**
1472          * Return a string representation of this title
1473          *
1474          * @return string Representation of this title
1475          */
1476         public function __toString() {
1477                 return $this->getPrefixedText();
1478         }
1479
1480         /**
1481          * Get the prefixed title with spaces, plus any fragment
1482          * (part beginning with '#')
1483          *
1484          * @return string The prefixed title, with spaces and the fragment, including '#'
1485          */
1486         public function getFullText() {
1487                 $text = $this->getPrefixedText();
1488                 if ( $this->hasFragment() ) {
1489                         $text .= '#' . $this->getFragment();
1490                 }
1491                 return $text;
1492         }
1493
1494         /**
1495          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1496          *
1497          * @par Example:
1498          * @code
1499          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1500          * # returns: 'Foo'
1501          * @endcode
1502          *
1503          * @return string Root name
1504          * @since 1.20
1505          */
1506         public function getRootText() {
1507                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1508                         return $this->getText();
1509                 }
1510
1511                 return strtok( $this->getText(), '/' );
1512         }
1513
1514         /**
1515          * Get the root page name title, i.e. the leftmost part before any slashes
1516          *
1517          * @par Example:
1518          * @code
1519          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1520          * # returns: Title{User:Foo}
1521          * @endcode
1522          *
1523          * @return Title Root title
1524          * @since 1.20
1525          */
1526         public function getRootTitle() {
1527                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1528         }
1529
1530         /**
1531          * Get the base page name without a namespace, i.e. the part before the subpage name
1532          *
1533          * @par Example:
1534          * @code
1535          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1536          * # returns: 'Foo/Bar'
1537          * @endcode
1538          *
1539          * @return string Base name
1540          */
1541         public function getBaseText() {
1542                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1543                         return $this->getText();
1544                 }
1545
1546                 $parts = explode( '/', $this->getText() );
1547                 # Don't discard the real title if there's no subpage involved
1548                 if ( count( $parts ) > 1 ) {
1549                         unset( $parts[count( $parts ) - 1] );
1550                 }
1551                 return implode( '/', $parts );
1552         }
1553
1554         /**
1555          * Get the base page name title, i.e. the part before the subpage name
1556          *
1557          * @par Example:
1558          * @code
1559          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1560          * # returns: Title{User:Foo/Bar}
1561          * @endcode
1562          *
1563          * @return Title Base title
1564          * @since 1.20
1565          */
1566         public function getBaseTitle() {
1567                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1568         }
1569
1570         /**
1571          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1572          *
1573          * @par Example:
1574          * @code
1575          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1576          * # returns: "Baz"
1577          * @endcode
1578          *
1579          * @return string Subpage name
1580          */
1581         public function getSubpageText() {
1582                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1583                         return $this->mTextform;
1584                 }
1585                 $parts = explode( '/', $this->mTextform );
1586                 return $parts[count( $parts ) - 1];
1587         }
1588
1589         /**
1590          * Get the title for a subpage of the current page
1591          *
1592          * @par Example:
1593          * @code
1594          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1595          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1596          * @endcode
1597          *
1598          * @param string $text The subpage name to add to the title
1599          * @return Title Subpage title
1600          * @since 1.20
1601          */
1602         public function getSubpage( $text ) {
1603                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1604         }
1605
1606         /**
1607          * Get a URL-encoded form of the subpage text
1608          *
1609          * @return string URL-encoded subpage name
1610          */
1611         public function getSubpageUrlForm() {
1612                 $text = $this->getSubpageText();
1613                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1614                 return $text;
1615         }
1616
1617         /**
1618          * Get a URL-encoded title (not an actual URL) including interwiki
1619          *
1620          * @return string The URL-encoded form
1621          */
1622         public function getPrefixedURL() {
1623                 $s = $this->prefix( $this->mDbkeyform );
1624                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1625                 return $s;
1626         }
1627
1628         /**
1629          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1630          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1631          * second argument named variant. This was deprecated in favor
1632          * of passing an array of option with a "variant" key
1633          * Once $query2 is removed for good, this helper can be dropped
1634          * and the wfArrayToCgi moved to getLocalURL();
1635          *
1636          * @since 1.19 (r105919)
1637          * @param array|string $query
1638          * @param bool $query2
1639          * @return string
1640          */
1641         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1642                 if ( $query2 !== false ) {
1643                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1644                                 "method called with a second parameter is deprecated. Add your " .
1645                                 "parameter to an array passed as the first parameter.", "1.19" );
1646                 }
1647                 if ( is_array( $query ) ) {
1648                         $query = wfArrayToCgi( $query );
1649                 }
1650                 if ( $query2 ) {
1651                         if ( is_string( $query2 ) ) {
1652                                 // $query2 is a string, we will consider this to be
1653                                 // a deprecated $variant argument and add it to the query
1654                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1655                         } else {
1656                                 $query2 = wfArrayToCgi( $query2 );
1657                         }
1658                         // If we have $query content add a & to it first
1659                         if ( $query ) {
1660                                 $query .= '&';
1661                         }
1662                         // Now append the queries together
1663                         $query .= $query2;
1664                 }
1665                 return $query;
1666         }
1667
1668         /**
1669          * Get a real URL referring to this title, with interwiki link and
1670          * fragment
1671          *
1672          * @see self::getLocalURL for the arguments.
1673          * @see wfExpandUrl
1674          * @param array|string $query
1675          * @param bool $query2
1676          * @param string $proto Protocol type to use in URL
1677          * @return string The URL
1678          */
1679         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1680                 $query = self::fixUrlQueryArgs( $query, $query2 );
1681
1682                 # Hand off all the decisions on urls to getLocalURL
1683                 $url = $this->getLocalURL( $query );
1684
1685                 # Expand the url to make it a full url. Note that getLocalURL has the
1686                 # potential to output full urls for a variety of reasons, so we use
1687                 # wfExpandUrl instead of simply prepending $wgServer
1688                 $url = wfExpandUrl( $url, $proto );
1689
1690                 # Finally, add the fragment.
1691                 $url .= $this->getFragmentForURL();
1692
1693                 Hooks::run( 'GetFullURL', array( &$this, &$url, $query ) );
1694                 return $url;
1695         }
1696
1697         /**
1698          * Get a URL with no fragment or server name (relative URL) from a Title object.
1699          * If this page is generated with action=render, however,
1700          * $wgServer is prepended to make an absolute URL.
1701          *
1702          * @see self::getFullURL to always get an absolute URL.
1703          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1704          *  valid to link, locally, to the current Title.
1705          * @see self::newFromText to produce a Title object.
1706          *
1707          * @param string|array $query An optional query string,
1708          *   not used for interwiki links. Can be specified as an associative array as well,
1709          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1710          *   Some query patterns will trigger various shorturl path replacements.
1711          * @param array $query2 An optional secondary query array. This one MUST
1712          *   be an array. If a string is passed it will be interpreted as a deprecated
1713          *   variant argument and urlencoded into a variant= argument.
1714          *   This second query argument will be added to the $query
1715          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1716          *   pair in the first parameter array instead.
1717          *
1718          * @return string String of the URL.
1719          */
1720         public function getLocalURL( $query = '', $query2 = false ) {
1721                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1722
1723                 $query = self::fixUrlQueryArgs( $query, $query2 );
1724
1725                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1726                 if ( $interwiki ) {
1727                         $namespace = $this->getNsText();
1728                         if ( $namespace != '' ) {
1729                                 # Can this actually happen? Interwikis shouldn't be parsed.
1730                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1731                                 $namespace .= ':';
1732                         }
1733                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1734                         $url = wfAppendQuery( $url, $query );
1735                 } else {
1736                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1737                         if ( $query == '' ) {
1738                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1739                                 Hooks::run( 'GetLocalURL::Article', array( &$this, &$url ) );
1740                         } else {
1741                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1742                                 $url = false;
1743                                 $matches = array();
1744
1745                                 if ( !empty( $wgActionPaths )
1746                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1747                                 ) {
1748                                         $action = urldecode( $matches[2] );
1749                                         if ( isset( $wgActionPaths[$action] ) ) {
1750                                                 $query = $matches[1];
1751                                                 if ( isset( $matches[4] ) ) {
1752                                                         $query .= $matches[4];
1753                                                 }
1754                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1755                                                 if ( $query != '' ) {
1756                                                         $url = wfAppendQuery( $url, $query );
1757                                                 }
1758                                         }
1759                                 }
1760
1761                                 if ( $url === false
1762                                         && $wgVariantArticlePath
1763                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1764                                         && $this->getPageLanguage()->hasVariants()
1765                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1766                                 ) {
1767                                         $variant = urldecode( $matches[1] );
1768                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1769                                                 // Only do the variant replacement if the given variant is a valid
1770                                                 // variant for the page's language.
1771                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1772                                                 $url = str_replace( '$1', $dbkey, $url );
1773                                         }
1774                                 }
1775
1776                                 if ( $url === false ) {
1777                                         if ( $query == '-' ) {
1778                                                 $query = '';
1779                                         }
1780                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1781                                 }
1782                         }
1783
1784                         Hooks::run( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1785
1786                         // @todo FIXME: This causes breakage in various places when we
1787                         // actually expected a local URL and end up with dupe prefixes.
1788                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1789                                 $url = $wgServer . $url;
1790                         }
1791                 }
1792                 Hooks::run( 'GetLocalURL', array( &$this, &$url, $query ) );
1793                 return $url;
1794         }
1795
1796         /**
1797          * Get a URL that's the simplest URL that will be valid to link, locally,
1798          * to the current Title.  It includes the fragment, but does not include
1799          * the server unless action=render is used (or the link is external).  If
1800          * there's a fragment but the prefixed text is empty, we just return a link
1801          * to the fragment.
1802          *
1803          * The result obviously should not be URL-escaped, but does need to be
1804          * HTML-escaped if it's being output in HTML.
1805          *
1806          * @param array $query
1807          * @param bool $query2
1808          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1809          * @see self::getLocalURL for the arguments.
1810          * @return string The URL
1811          */
1812         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1813                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1814                         $ret = $this->getFullURL( $query, $query2, $proto );
1815                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1816                         $ret = $this->getFragmentForURL();
1817                 } else {
1818                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1819                 }
1820                 return $ret;
1821         }
1822
1823         /**
1824          * Get the URL form for an internal link.
1825          * - Used in various Squid-related code, in case we have a different
1826          * internal hostname for the server from the exposed one.
1827          *
1828          * This uses $wgInternalServer to qualify the path, or $wgServer
1829          * if $wgInternalServer is not set. If the server variable used is
1830          * protocol-relative, the URL will be expanded to http://
1831          *
1832          * @see self::getLocalURL for the arguments.
1833          * @return string The URL
1834          */
1835         public function getInternalURL( $query = '', $query2 = false ) {
1836                 global $wgInternalServer, $wgServer;
1837                 $query = self::fixUrlQueryArgs( $query, $query2 );
1838                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1839                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1840                 Hooks::run( 'GetInternalURL', array( &$this, &$url, $query ) );
1841                 return $url;
1842         }
1843
1844         /**
1845          * Get the URL for a canonical link, for use in things like IRC and
1846          * e-mail notifications. Uses $wgCanonicalServer and the
1847          * GetCanonicalURL hook.
1848          *
1849          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1850          *
1851          * @see self::getLocalURL for the arguments.
1852          * @return string The URL
1853          * @since 1.18
1854          */
1855         public function getCanonicalURL( $query = '', $query2 = false ) {
1856                 $query = self::fixUrlQueryArgs( $query, $query2 );
1857                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1858                 Hooks::run( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1859                 return $url;
1860         }
1861
1862         /**
1863          * Get the edit URL for this Title
1864          *
1865          * @return string The URL, or a null string if this is an interwiki link
1866          */
1867         public function getEditURL() {
1868                 if ( $this->isExternal() ) {
1869                         return '';
1870                 }
1871                 $s = $this->getLocalURL( 'action=edit' );
1872
1873                 return $s;
1874         }
1875
1876         /**
1877          * Is $wgUser watching this page?
1878          *
1879          * @deprecated since 1.20; use User::isWatched() instead.
1880          * @return bool
1881          */
1882         public function userIsWatching() {
1883                 global $wgUser;
1884
1885                 if ( is_null( $this->mWatched ) ) {
1886                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1887                                 $this->mWatched = false;
1888                         } else {
1889                                 $this->mWatched = $wgUser->isWatched( $this );
1890                         }
1891                 }
1892                 return $this->mWatched;
1893         }
1894
1895         /**
1896          * Can $user perform $action on this page?
1897          * This skips potentially expensive cascading permission checks
1898          * as well as avoids expensive error formatting
1899          *
1900          * Suitable for use for nonessential UI controls in common cases, but
1901          * _not_ for functional access control.
1902          *
1903          * May provide false positives, but should never provide a false negative.
1904          *
1905          * @param string $action Action that permission needs to be checked for
1906          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1907          * @return bool
1908          */
1909         public function quickUserCan( $action, $user = null ) {
1910                 return $this->userCan( $action, $user, false );
1911         }
1912
1913         /**
1914          * Can $user perform $action on this page?
1915          *
1916          * @param string $action Action that permission needs to be checked for
1917          * @param User $user User to check (since 1.19); $wgUser will be used if not
1918          *   provided.
1919          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1920          * @return bool
1921          */
1922         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1923                 if ( !$user instanceof User ) {
1924                         global $wgUser;
1925                         $user = $wgUser;
1926                 }
1927
1928                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1929         }
1930
1931         /**
1932          * Can $user perform $action on this page?
1933          *
1934          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1935          *
1936          * @param string $action Action that permission needs to be checked for
1937          * @param User $user User to check
1938          * @param string $rigor One of (quick,full,secure)
1939          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
1940          *   - full   : does cheap and expensive checks possibly from a slave
1941          *   - secure : does cheap and expensive checks, using the master as needed
1942          * @param bool $short Set this to true to stop after the first permission error.
1943          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1944          *   whose corresponding errors may be ignored.
1945          * @return array Array of arguments to wfMessage to explain permissions problems.
1946          */
1947         public function getUserPermissionsErrors(
1948                 $action, $user, $rigor = 'secure', $ignoreErrors = array()
1949         ) {
1950                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1951
1952                 // Remove the errors being ignored.
1953                 foreach ( $errors as $index => $error ) {
1954                         $error_key = is_array( $error ) ? $error[0] : $error;
1955
1956                         if ( in_array( $error_key, $ignoreErrors ) ) {
1957                                 unset( $errors[$index] );
1958                         }
1959                 }
1960
1961                 return $errors;
1962         }
1963
1964         /**
1965          * Permissions checks that fail most often, and which are easiest to test.
1966          *
1967          * @param string $action The action to check
1968          * @param User $user User to check
1969          * @param array $errors List of current errors
1970          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1971          * @param bool $short Short circuit on first error
1972          *
1973          * @return array List of errors
1974          */
1975         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1976                 if ( !Hooks::run( 'TitleQuickPermissions',
1977                         array( $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ) )
1978                 ) {
1979                         return $errors;
1980                 }
1981
1982                 if ( $action == 'create' ) {
1983                         if (
1984                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1985                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1986                         ) {
1987                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1988                         }
1989                 } elseif ( $action == 'move' ) {
1990                         if ( !$user->isAllowed( 'move-rootuserpages' )
1991                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1992                                 // Show user page-specific message only if the user can move other pages
1993                                 $errors[] = array( 'cant-move-user-page' );
1994                         }
1995
1996                         // Check if user is allowed to move files if it's a file
1997                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1998                                 $errors[] = array( 'movenotallowedfile' );
1999                         }
2000
2001                         // Check if user is allowed to move category pages if it's a category page
2002                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2003                                 $errors[] = array( 'cant-move-category-page' );
2004                         }
2005
2006                         if ( !$user->isAllowed( 'move' ) ) {
2007                                 // User can't move anything
2008                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2009                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2010                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2011                                         // custom message if logged-in users without any special rights can move
2012                                         $errors[] = array( 'movenologintext' );
2013                                 } else {
2014                                         $errors[] = array( 'movenotallowed' );
2015                                 }
2016                         }
2017                 } elseif ( $action == 'move-target' ) {
2018                         if ( !$user->isAllowed( 'move' ) ) {
2019                                 // User can't move anything
2020                                 $errors[] = array( 'movenotallowed' );
2021                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2022                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2023                                 // Show user page-specific message only if the user can move other pages
2024                                 $errors[] = array( 'cant-move-to-user-page' );
2025                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2026                                         && $this->mNamespace == NS_CATEGORY ) {
2027                                 // Show category page-specific message only if the user can move other pages
2028                                 $errors[] = array( 'cant-move-to-category-page' );
2029                         }
2030                 } elseif ( !$user->isAllowed( $action ) ) {
2031                         $errors[] = $this->missingPermissionError( $action, $short );
2032                 }
2033
2034                 return $errors;
2035         }
2036
2037         /**
2038          * Add the resulting error code to the errors array
2039          *
2040          * @param array $errors List of current errors
2041          * @param array $result Result of errors
2042          *
2043          * @return array List of errors
2044          */
2045         private function resultToError( $errors, $result ) {
2046                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2047                         // A single array representing an error
2048                         $errors[] = $result;
2049                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2050                         // A nested array representing multiple errors
2051                         $errors = array_merge( $errors, $result );
2052                 } elseif ( $result !== '' && is_string( $result ) ) {
2053                         // A string representing a message-id
2054                         $errors[] = array( $result );
2055                 } elseif ( $result === false ) {
2056                         // a generic "We don't want them to do that"
2057                         $errors[] = array( 'badaccess-group0' );
2058                 }
2059                 return $errors;
2060         }
2061
2062         /**
2063          * Check various permission hooks
2064          *
2065          * @param string $action The action to check
2066          * @param User $user User to check
2067          * @param array $errors List of current errors
2068          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2069          * @param bool $short Short circuit on first error
2070          *
2071          * @return array List of errors
2072          */
2073         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2074                 // Use getUserPermissionsErrors instead
2075                 $result = '';
2076                 if ( !Hooks::run( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2077                         return $result ? array() : array( array( 'badaccess-group0' ) );
2078                 }
2079                 // Check getUserPermissionsErrors hook
2080                 if ( !Hooks::run( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2081                         $errors = $this->resultToError( $errors, $result );
2082                 }
2083                 // Check getUserPermissionsErrorsExpensive hook
2084                 if (
2085                         $rigor !== 'quick'
2086                         && !( $short && count( $errors ) > 0 )
2087                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2088                 ) {
2089                         $errors = $this->resultToError( $errors, $result );
2090                 }
2091
2092                 return $errors;
2093         }
2094
2095         /**
2096          * Check permissions on special pages & namespaces
2097          *
2098          * @param string $action The action to check
2099          * @param User $user User to check
2100          * @param array $errors List of current errors
2101          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2102          * @param bool $short Short circuit on first error
2103          *
2104          * @return array List of errors
2105          */
2106         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2107                 # Only 'createaccount' can be performed on special pages,
2108                 # which don't actually exist in the DB.
2109                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2110                         $errors[] = array( 'ns-specialprotected' );
2111                 }
2112
2113                 # Check $wgNamespaceProtection for restricted namespaces
2114                 if ( $this->isNamespaceProtected( $user ) ) {
2115                         $ns = $this->mNamespace == NS_MAIN ?
2116                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2117                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2118                                 array( 'protectedinterface', $action ) : array( 'namespaceprotected', $ns, $action );
2119                 }
2120
2121                 return $errors;
2122         }
2123
2124         /**
2125          * Check CSS/JS sub-page permissions
2126          *
2127          * @param string $action The action to check
2128          * @param User $user User to check
2129          * @param array $errors List of current errors
2130          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2131          * @param bool $short Short circuit on first error
2132          *
2133          * @return array List of errors
2134          */
2135         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2136                 # Protect css/js subpages of user pages
2137                 # XXX: this might be better using restrictions
2138                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2139                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2140                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2141                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2142                                         $errors[] = array( 'mycustomcssprotected', $action );
2143                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2144                                         $errors[] = array( 'mycustomjsprotected', $action );
2145                                 }
2146                         } else {
2147                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2148                                         $errors[] = array( 'customcssprotected', $action );
2149                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2150                                         $errors[] = array( 'customjsprotected', $action );
2151                                 }
2152                         }
2153                 }
2154
2155                 return $errors;
2156         }
2157
2158         /**
2159          * Check against page_restrictions table requirements on this
2160          * page. The user must possess all required rights for this
2161          * action.
2162          *
2163          * @param string $action The action to check
2164          * @param User $user User to check
2165          * @param array $errors List of current errors
2166          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2167          * @param bool $short Short circuit on first error
2168          *
2169          * @return array List of errors
2170          */
2171         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2172                 foreach ( $this->getRestrictions( $action ) as $right ) {
2173                         // Backwards compatibility, rewrite sysop -> editprotected
2174                         if ( $right == 'sysop' ) {
2175                                 $right = 'editprotected';
2176                         }
2177                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2178                         if ( $right == 'autoconfirmed' ) {
2179                                 $right = 'editsemiprotected';
2180                         }
2181                         if ( $right == '' ) {
2182                                 continue;
2183                         }
2184                         if ( !$user->isAllowed( $right ) ) {
2185                                 $errors[] = array( 'protectedpagetext', $right, $action );
2186                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2187                                 $errors[] = array( 'protectedpagetext', 'protect', $action );
2188                         }
2189                 }
2190
2191                 return $errors;
2192         }
2193
2194         /**
2195          * Check restrictions on cascading pages.
2196          *
2197          * @param string $action The action to check
2198          * @param User $user User to check
2199          * @param array $errors List of current errors
2200          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2201          * @param bool $short Short circuit on first error
2202          *
2203          * @return array List of errors
2204          */
2205         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2206                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2207                         # We /could/ use the protection level on the source page, but it's
2208                         # fairly ugly as we have to establish a precedence hierarchy for pages
2209                         # included by multiple cascade-protected pages. So just restrict
2210                         # it to people with 'protect' permission, as they could remove the
2211                         # protection anyway.
2212                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2213                         # Cascading protection depends on more than this page...
2214                         # Several cascading protected pages may include this page...
2215                         # Check each cascading level
2216                         # This is only for protection restrictions, not for all actions
2217                         if ( isset( $restrictions[$action] ) ) {
2218                                 foreach ( $restrictions[$action] as $right ) {
2219                                         // Backwards compatibility, rewrite sysop -> editprotected
2220                                         if ( $right == 'sysop' ) {
2221                                                 $right = 'editprotected';
2222                                         }
2223                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2224                                         if ( $right == 'autoconfirmed' ) {
2225                                                 $right = 'editsemiprotected';
2226                                         }
2227                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2228                                                 $pages = '';
2229                                                 foreach ( $cascadingSources as $page ) {
2230                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2231                                                 }
2232                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages, $action );
2233                                         }
2234                                 }
2235                         }
2236                 }
2237
2238                 return $errors;
2239         }
2240
2241         /**
2242          * Check action permissions not already checked in checkQuickPermissions
2243          *
2244          * @param string $action The action to check
2245          * @param User $user User to check
2246          * @param array $errors List of current errors
2247          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2248          * @param bool $short Short circuit on first error
2249          *
2250          * @return array List of errors
2251          */
2252         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2253                 global $wgDeleteRevisionsLimit, $wgLang;
2254
2255                 if ( $action == 'protect' ) {
2256                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2257                                 // If they can't edit, they shouldn't protect.
2258                                 $errors[] = array( 'protect-cantedit' );
2259                         }
2260                 } elseif ( $action == 'create' ) {
2261                         $title_protection = $this->getTitleProtection();
2262                         if ( $title_protection ) {
2263                                 if ( $title_protection['permission'] == ''
2264                                         || !$user->isAllowed( $title_protection['permission'] )
2265                                 ) {
2266                                         $errors[] = array(
2267                                                 'titleprotected',
2268                                                 User::whoIs( $title_protection['user'] ),
2269                                                 $title_protection['reason']
2270                                         );
2271                                 }
2272                         }
2273                 } elseif ( $action == 'move' ) {
2274                         // Check for immobile pages
2275                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2276                                 // Specific message for this case
2277                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2278                         } elseif ( !$this->isMovable() ) {
2279                                 // Less specific message for rarer cases
2280                                 $errors[] = array( 'immobile-source-page' );
2281                         }
2282                 } elseif ( $action == 'move-target' ) {
2283                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2284                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2285                         } elseif ( !$this->isMovable() ) {
2286                                 $errors[] = array( 'immobile-target-page' );
2287                         }
2288                 } elseif ( $action == 'delete' ) {
2289                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, array(), $rigor, true );
2290                         if ( !$tempErrors ) {
2291                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2292                                         $user, $tempErrors, $rigor, true );
2293                         }
2294                         if ( $tempErrors ) {
2295                                 // If protection keeps them from editing, they shouldn't be able to delete.
2296                                 $errors[] = array( 'deleteprotected' );
2297                         }
2298                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2299                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2300                         ) {
2301                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2302                         }
2303                 }
2304                 return $errors;
2305         }
2306
2307         /**
2308          * Check that the user isn't blocked from editing.
2309          *
2310          * @param string $action The action to check
2311          * @param User $user User to check
2312          * @param array $errors List of current errors
2313          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2314          * @param bool $short Short circuit on first error
2315          *
2316          * @return array List of errors
2317          */
2318         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2319                 // Account creation blocks handled at userlogin.
2320                 // Unblocking handled in SpecialUnblock
2321                 if ( $rigor === 'quick' || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2322                         return $errors;
2323                 }
2324
2325                 global $wgEmailConfirmToEdit;
2326
2327                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2328                         $errors[] = array( 'confirmedittext' );
2329                 }
2330
2331                 $useSlave = ( $rigor !== 'secure' );
2332                 if ( ( $action == 'edit' || $action == 'create' )
2333                         && !$user->isBlockedFrom( $this, $useSlave )
2334                 ) {
2335                         // Don't block the user from editing their own talk page unless they've been
2336                         // explicitly blocked from that too.
2337                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2338                         // @todo FIXME: Pass the relevant context into this function.
2339                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2340                 }
2341
2342                 return $errors;
2343         }
2344
2345         /**
2346          * Check that the user is allowed to read this page.
2347          *
2348          * @param string $action The action to check
2349          * @param User $user User to check
2350          * @param array $errors List of current errors
2351          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2352          * @param bool $short Short circuit on first error
2353          *
2354          * @return array List of errors
2355          */
2356         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2357                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2358
2359                 $whitelisted = false;
2360                 if ( User::isEveryoneAllowed( 'read' ) ) {
2361                         # Shortcut for public wikis, allows skipping quite a bit of code
2362                         $whitelisted = true;
2363                 } elseif ( $user->isAllowed( 'read' ) ) {
2364                         # If the user is allowed to read pages, he is allowed to read all pages
2365                         $whitelisted = true;
2366                 } elseif ( $this->isSpecial( 'Userlogin' )
2367                         || $this->isSpecial( 'ChangePassword' )
2368                         || $this->isSpecial( 'PasswordReset' )
2369                 ) {
2370                         # Always grant access to the login page.
2371                         # Even anons need to be able to log in.
2372                         $whitelisted = true;
2373                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2374                         # Time to check the whitelist
2375                         # Only do these checks is there's something to check against
2376                         $name = $this->getPrefixedText();
2377                         $dbName = $this->getPrefixedDBkey();
2378
2379                         // Check for explicit whitelisting with and without underscores
2380                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2381                                 $whitelisted = true;
2382                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2383                                 # Old settings might have the title prefixed with
2384                                 # a colon for main-namespace pages
2385                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2386                                         $whitelisted = true;
2387                                 }
2388                         } elseif ( $this->isSpecialPage() ) {
2389                                 # If it's a special page, ditch the subpage bit and check again
2390                                 $name = $this->getDBkey();
2391                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2392                                 if ( $name ) {
2393                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2394                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2395                                                 $whitelisted = true;
2396                                         }
2397                                 }
2398                         }
2399                 }
2400
2401                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2402                         $name = $this->getPrefixedText();
2403                         // Check for regex whitelisting
2404                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2405                                 if ( preg_match( $listItem, $name ) ) {
2406                                         $whitelisted = true;
2407                                         break;
2408                                 }
2409                         }
2410                 }
2411
2412                 if ( !$whitelisted ) {
2413                         # If the title is not whitelisted, give extensions a chance to do so...
2414                         Hooks::run( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2415                         if ( !$whitelisted ) {
2416                                 $errors[] = $this->missingPermissionError( $action, $short );
2417                         }
2418                 }
2419
2420                 return $errors;
2421         }
2422
2423         /**
2424          * Get a description array when the user doesn't have the right to perform
2425          * $action (i.e. when User::isAllowed() returns false)
2426          *
2427          * @param string $action The action to check
2428          * @param bool $short Short circuit on first error
2429          * @return array List of errors
2430          */
2431         private function missingPermissionError( $action, $short ) {
2432                 // We avoid expensive display logic for quickUserCan's and such
2433                 if ( $short ) {
2434                         return array( 'badaccess-group0' );
2435                 }
2436
2437                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2438                         User::getGroupsWithPermission( $action ) );
2439
2440                 if ( count( $groups ) ) {
2441                         global $wgLang;
2442                         return array(
2443                                 'badaccess-groups',
2444                                 $wgLang->commaList( $groups ),
2445                                 count( $groups )
2446                         );
2447                 } else {
2448                         return array( 'badaccess-group0' );
2449                 }
2450         }
2451
2452         /**
2453          * Can $user perform $action on this page? This is an internal function,
2454          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2455          * checks on wfReadOnly() and blocks)
2456          *
2457          * @param string $action Action that permission needs to be checked for
2458          * @param User $user User to check
2459          * @param string $rigor One of (quick,full,secure)
2460          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
2461          *   - full   : does cheap and expensive checks possibly from a slave
2462          *   - secure : does cheap and expensive checks, using the master as needed
2463          * @param bool $short Set this to true to stop after the first permission error.
2464          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2465          */
2466         protected function getUserPermissionsErrorsInternal(
2467                 $action, $user, $rigor = 'secure', $short = false
2468         ) {
2469                 if ( $rigor === true ) {
2470                         $rigor = 'secure'; // b/c
2471                 } elseif ( $rigor === false ) {
2472                         $rigor = 'quick'; // b/c
2473                 } elseif ( !in_array( $rigor, array( 'quick', 'full', 'secure' ) ) ) {
2474                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2475                 }
2476
2477                 # Read has special handling
2478                 if ( $action == 'read' ) {
2479                         $checks = array(
2480                                 'checkPermissionHooks',
2481                                 'checkReadPermissions',
2482                         );
2483                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2484                 # here as it will lead to duplicate error messages. This is okay to do
2485                 # since anywhere that checks for create will also check for edit, and
2486                 # those checks are called for edit.
2487                 } elseif ( $action == 'create' ) {
2488                         $checks = array(
2489                                 'checkQuickPermissions',
2490                                 'checkPermissionHooks',
2491                                 'checkPageRestrictions',
2492                                 'checkCascadingSourcesRestrictions',
2493                                 'checkActionPermissions',
2494                                 'checkUserBlock'
2495                         );
2496                 } else {
2497                         $checks = array(
2498                                 'checkQuickPermissions',
2499                                 'checkPermissionHooks',
2500                                 'checkSpecialsAndNSPermissions',
2501                                 'checkCSSandJSPermissions',
2502                                 'checkPageRestrictions',
2503                                 'checkCascadingSourcesRestrictions',
2504                                 'checkActionPermissions',
2505                                 'checkUserBlock'
2506                         );
2507                 }
2508
2509                 $errors = array();
2510                 while ( count( $checks ) > 0 &&
2511                                 !( $short && count( $errors ) > 0 ) ) {
2512                         $method = array_shift( $checks );
2513                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2514                 }
2515
2516                 return $errors;
2517         }
2518
2519         /**
2520          * Get a filtered list of all restriction types supported by this wiki.
2521          * @param bool $exists True to get all restriction types that apply to
2522          * titles that do exist, False for all restriction types that apply to
2523          * titles that do not exist
2524          * @return array
2525          */
2526         public static function getFilteredRestrictionTypes( $exists = true ) {
2527                 global $wgRestrictionTypes;
2528                 $types = $wgRestrictionTypes;
2529                 if ( $exists ) {
2530                         # Remove the create restriction for existing titles
2531                         $types = array_diff( $types, array( 'create' ) );
2532                 } else {
2533                         # Only the create and upload restrictions apply to non-existing titles
2534                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2535                 }
2536                 return $types;
2537         }
2538
2539         /**
2540          * Returns restriction types for the current Title
2541          *
2542          * @return array Applicable restriction types
2543          */
2544         public function getRestrictionTypes() {
2545                 if ( $this->isSpecialPage() ) {
2546                         return array();
2547                 }
2548
2549                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2550
2551                 if ( $this->getNamespace() != NS_FILE ) {
2552                         # Remove the upload restriction for non-file titles
2553                         $types = array_diff( $types, array( 'upload' ) );
2554                 }
2555
2556                 Hooks::run( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2557
2558                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2559                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2560
2561                 return $types;
2562         }
2563
2564         /**
2565          * Is this title subject to title protection?
2566          * Title protection is the one applied against creation of such title.
2567          *
2568          * @return array|bool An associative array representing any existent title
2569          *   protection, or false if there's none.
2570          */
2571         public function getTitleProtection() {
2572                 // Can't protect pages in special namespaces
2573                 if ( $this->getNamespace() < 0 ) {
2574                         return false;
2575                 }
2576
2577                 // Can't protect pages that exist.
2578                 if ( $this->exists() ) {
2579                         return false;
2580                 }
2581
2582                 if ( $this->mTitleProtection === null ) {
2583                         $dbr = wfGetDB( DB_SLAVE );
2584                         $res = $dbr->select(
2585                                 'protected_titles',
2586                                 array(
2587                                         'user' => 'pt_user',
2588                                         'reason' => 'pt_reason',
2589                                         'expiry' => 'pt_expiry',
2590                                         'permission' => 'pt_create_perm'
2591                                 ),
2592                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2593                                 __METHOD__
2594                         );
2595
2596                         // fetchRow returns false if there are no rows.
2597                         $row = $dbr->fetchRow( $res );
2598                         if ( $row ) {
2599                                 if ( $row['permission'] == 'sysop' ) {
2600                                         $row['permission'] = 'editprotected'; // B/C
2601                                 }
2602                                 if ( $row['permission'] == 'autoconfirmed' ) {
2603                                         $row['permission'] = 'editsemiprotected'; // B/C
2604                                 }
2605                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2606                         }
2607                         $this->mTitleProtection = $row;
2608                 }
2609                 return $this->mTitleProtection;
2610         }
2611
2612         /**
2613          * Remove any title protection due to page existing
2614          */
2615         public function deleteTitleProtection() {
2616                 $dbw = wfGetDB( DB_MASTER );
2617
2618                 $dbw->delete(
2619                         'protected_titles',
2620                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2621                         __METHOD__
2622                 );
2623                 $this->mTitleProtection = false;
2624         }
2625
2626         /**
2627          * Is this page "semi-protected" - the *only* protection levels are listed
2628          * in $wgSemiprotectedRestrictionLevels?
2629          *
2630          * @param string $action Action to check (default: edit)
2631          * @return bool
2632          */
2633         public function isSemiProtected( $action = 'edit' ) {
2634                 global $wgSemiprotectedRestrictionLevels;
2635
2636                 $restrictions = $this->getRestrictions( $action );
2637                 $semi = $wgSemiprotectedRestrictionLevels;
2638                 if ( !$restrictions || !$semi ) {
2639                         // Not protected, or all protection is full protection
2640                         return false;
2641                 }
2642
2643                 // Remap autoconfirmed to editsemiprotected for BC
2644                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2645                         $semi[$key] = 'editsemiprotected';
2646                 }
2647                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2648                         $restrictions[$key] = 'editsemiprotected';
2649                 }
2650
2651                 return !array_diff( $restrictions, $semi );
2652         }
2653
2654         /**
2655          * Does the title correspond to a protected article?
2656          *
2657          * @param string $action The action the page is protected from,
2658          * by default checks all actions.
2659          * @return bool
2660          */
2661         public function isProtected( $action = '' ) {
2662                 global $wgRestrictionLevels;
2663
2664                 $restrictionTypes = $this->getRestrictionTypes();
2665
2666                 # Special pages have inherent protection
2667                 if ( $this->isSpecialPage() ) {
2668                         return true;
2669                 }
2670
2671                 # Check regular protection levels
2672                 foreach ( $restrictionTypes as $type ) {
2673                         if ( $action == $type || $action == '' ) {
2674                                 $r = $this->getRestrictions( $type );
2675                                 foreach ( $wgRestrictionLevels as $level ) {
2676                                         if ( in_array( $level, $r ) && $level != '' ) {
2677                                                 return true;
2678                                         }
2679                                 }
2680                         }
2681                 }
2682
2683                 return false;
2684         }
2685
2686         /**
2687          * Determines if $user is unable to edit this page because it has been protected
2688          * by $wgNamespaceProtection.
2689          *
2690          * @param User $user User object to check permissions
2691          * @return bool
2692          */
2693         public function isNamespaceProtected( User $user ) {
2694                 global $wgNamespaceProtection;
2695
2696                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2697                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2698                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2699                                         return true;
2700                                 }
2701                         }
2702                 }
2703                 return false;
2704         }
2705
2706         /**
2707          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2708          *
2709          * @return bool If the page is subject to cascading restrictions.
2710          */
2711         public function isCascadeProtected() {
2712                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2713                 return ( $sources > 0 );
2714         }
2715
2716         /**
2717          * Determines whether cascading protection sources have already been loaded from
2718          * the database.
2719          *
2720          * @param bool $getPages True to check if the pages are loaded, or false to check
2721          * if the status is loaded.
2722          * @return bool Whether or not the specified information has been loaded
2723          * @since 1.23
2724          */
2725         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2726                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2727         }
2728
2729         /**
2730          * Cascading protection: Get the source of any cascading restrictions on this page.
2731          *
2732          * @param bool $getPages Whether or not to retrieve the actual pages
2733          *        that the restrictions have come from and the actual restrictions
2734          *        themselves.
2735          * @return array Two elements: First is an array of Title objects of the
2736          *        pages from which cascading restrictions have come, false for
2737          *        none, or true if such restrictions exist but $getPages was not
2738          *        set. Second is an array like that returned by
2739          *        Title::getAllRestrictions(), or an empty array if $getPages is
2740          *        false.
2741          */
2742         public function getCascadeProtectionSources( $getPages = true ) {
2743                 $pagerestrictions = array();
2744
2745                 if ( $this->mCascadeSources !== null && $getPages ) {
2746                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2747                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2748                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2749                 }
2750
2751                 $dbr = wfGetDB( DB_SLAVE );
2752
2753                 if ( $this->getNamespace() == NS_FILE ) {
2754                         $tables = array( 'imagelinks', 'page_restrictions' );
2755                         $where_clauses = array(
2756                                 'il_to' => $this->getDBkey(),
2757                                 'il_from=pr_page',
2758                                 'pr_cascade' => 1
2759                         );
2760                 } else {
2761                         $tables = array( 'templatelinks', 'page_restrictions' );
2762                         $where_clauses = array(
2763                                 'tl_namespace' => $this->getNamespace(),
2764                                 'tl_title' => $this->getDBkey(),
2765                                 'tl_from=pr_page',
2766                                 'pr_cascade' => 1
2767                         );
2768                 }
2769
2770                 if ( $getPages ) {
2771                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2772                                 'pr_expiry', 'pr_type', 'pr_level' );
2773                         $where_clauses[] = 'page_id=pr_page';
2774                         $tables[] = 'page';
2775                 } else {
2776                         $cols = array( 'pr_expiry' );
2777                 }
2778
2779                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2780
2781                 $sources = $getPages ? array() : false;
2782                 $now = wfTimestampNow();
2783
2784                 foreach ( $res as $row ) {
2785                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2786                         if ( $expiry > $now ) {
2787                                 if ( $getPages ) {
2788                                         $page_id = $row->pr_page;
2789                                         $page_ns = $row->page_namespace;
2790                                         $page_title = $row->page_title;
2791                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2792                                         # Add groups needed for each restriction type if its not already there
2793                                         # Make sure this restriction type still exists
2794
2795                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2796                                                 $pagerestrictions[$row->pr_type] = array();
2797                                         }
2798
2799                                         if (
2800                                                 isset( $pagerestrictions[$row->pr_type] )
2801                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2802                                         ) {
2803                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2804                                         }
2805                                 } else {
2806                                         $sources = true;
2807                                 }
2808                         }
2809                 }
2810
2811                 if ( $getPages ) {
2812                         $this->mCascadeSources = $sources;
2813                         $this->mCascadingRestrictions = $pagerestrictions;
2814                 } else {
2815                         $this->mHasCascadingRestrictions = $sources;
2816                 }
2817
2818                 return array( $sources, $pagerestrictions );
2819         }
2820
2821         /**
2822          * Accessor for mRestrictionsLoaded
2823          *
2824          * @return bool Whether or not the page's restrictions have already been
2825          * loaded from the database
2826          * @since 1.23
2827          */
2828         public function areRestrictionsLoaded() {
2829                 return $this->mRestrictionsLoaded;
2830         }
2831
2832         /**
2833          * Accessor/initialisation for mRestrictions
2834          *
2835          * @param string $action Action that permission needs to be checked for
2836          * @return array Restriction levels needed to take the action. All levels are
2837          *     required. Note that restriction levels are normally user rights, but 'sysop'
2838          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2839          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2840          */
2841         public function getRestrictions( $action ) {
2842                 if ( !$this->mRestrictionsLoaded ) {
2843                         $this->loadRestrictions();
2844                 }
2845                 return isset( $this->mRestrictions[$action] )
2846                                 ? $this->mRestrictions[$action]
2847                                 : array();
2848         }
2849
2850         /**
2851          * Accessor/initialisation for mRestrictions
2852          *
2853          * @return array Keys are actions, values are arrays as returned by
2854          *     Title::getRestrictions()
2855          * @since 1.23
2856          */
2857         public function getAllRestrictions() {
2858                 if ( !$this->mRestrictionsLoaded ) {
2859                         $this->loadRestrictions();
2860                 }
2861                 return $this->mRestrictions;
2862         }
2863
2864         /**
2865          * Get the expiry time for the restriction against a given action
2866          *
2867          * @param string $action
2868          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2869          *     or not protected at all, or false if the action is not recognised.
2870          */
2871         public function getRestrictionExpiry( $action ) {
2872                 if ( !$this->mRestrictionsLoaded ) {
2873                         $this->loadRestrictions();
2874                 }
2875                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2876         }
2877
2878         /**
2879          * Returns cascading restrictions for the current article
2880          *
2881          * @return bool
2882          */
2883         function areRestrictionsCascading() {
2884                 if ( !$this->mRestrictionsLoaded ) {
2885                         $this->loadRestrictions();
2886                 }
2887
2888                 return $this->mCascadeRestriction;
2889         }
2890
2891         /**
2892          * Loads a string into mRestrictions array
2893          *
2894          * @param ResultWrapper $res Resource restrictions as an SQL result.
2895          * @param string $oldFashionedRestrictions Comma-separated list of page
2896          *        restrictions from page table (pre 1.10)
2897          */
2898         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2899                 $rows = array();
2900
2901                 foreach ( $res as $row ) {
2902                         $rows[] = $row;
2903                 }
2904
2905                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2906         }
2907
2908         /**
2909          * Compiles list of active page restrictions from both page table (pre 1.10)
2910          * and page_restrictions table for this existing page.
2911          * Public for usage by LiquidThreads.
2912          *
2913          * @param array $rows Array of db result objects
2914          * @param string $oldFashionedRestrictions Comma-separated list of page
2915          *   restrictions from page table (pre 1.10)
2916          */
2917         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2918                 $dbr = wfGetDB( DB_SLAVE );
2919
2920                 $restrictionTypes = $this->getRestrictionTypes();
2921
2922                 foreach ( $restrictionTypes as $type ) {
2923                         $this->mRestrictions[$type] = array();
2924                         $this->mRestrictionsExpiry[$type] = 'infinity';
2925                 }
2926
2927                 $this->mCascadeRestriction = false;
2928
2929                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2930                 if ( $oldFashionedRestrictions !== null ) {
2931                         $this->mOldRestrictions = $oldFashionedRestrictions;
2932                 }
2933
2934                 if ( $this->mOldRestrictions === false ) {
2935                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2936                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2937                 }
2938
2939                 if ( $this->mOldRestrictions != '' ) {
2940                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2941                                 $temp = explode( '=', trim( $restrict ) );
2942                                 if ( count( $temp ) == 1 ) {
2943                                         // old old format should be treated as edit/move restriction
2944                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2945                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2946                                 } else {
2947                                         $restriction = trim( $temp[1] );
2948                                         if ( $restriction != '' ) { //some old entries are empty
2949                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2950                                         }
2951                                 }
2952                         }
2953                 }
2954
2955                 if ( count( $rows ) ) {
2956                         # Current system - load second to make them override.
2957                         $now = wfTimestampNow();
2958
2959                         # Cycle through all the restrictions.
2960                         foreach ( $rows as $row ) {
2961
2962                                 // Don't take care of restrictions types that aren't allowed
2963                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2964                                         continue;
2965                                 }
2966
2967                                 // This code should be refactored, now that it's being used more generally,
2968                                 // But I don't really see any harm in leaving it in Block for now -werdna
2969                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2970
2971                                 // Only apply the restrictions if they haven't expired!
2972                                 if ( !$expiry || $expiry > $now ) {
2973                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2974                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2975
2976                                         $this->mCascadeRestriction |= $row->pr_cascade;
2977                                 }
2978                         }
2979                 }
2980
2981                 $this->mRestrictionsLoaded = true;
2982         }
2983
2984         /**
2985          * Load restrictions from the page_restrictions table
2986          *
2987          * @param string $oldFashionedRestrictions Comma-separated list of page
2988          *   restrictions from page table (pre 1.10)
2989          */
2990         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2991                 if ( !$this->mRestrictionsLoaded ) {
2992                         $dbr = wfGetDB( DB_SLAVE );
2993                         if ( $this->exists() ) {
2994                                 $res = $dbr->select(
2995                                         'page_restrictions',
2996                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2997                                         array( 'pr_page' => $this->getArticleID() ),
2998                                         __METHOD__
2999                                 );
3000
3001                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
3002                         } else {
3003                                 $title_protection = $this->getTitleProtection();
3004
3005                                 if ( $title_protection ) {
3006                                         $now = wfTimestampNow();
3007                                         $expiry = $dbr->decodeExpiry( $title_protection['expiry'] );
3008
3009                                         if ( !$expiry || $expiry > $now ) {
3010                                                 // Apply the restrictions
3011                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3012                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
3013                                         } else { // Get rid of the old restrictions
3014                                                 $this->mTitleProtection = false;
3015                                         }
3016                                 } else {
3017                                         $this->mRestrictionsExpiry['create'] = 'infinity';
3018                                 }
3019                                 $this->mRestrictionsLoaded = true;
3020                         }
3021                 }
3022         }
3023
3024         /**
3025          * Flush the protection cache in this object and force reload from the database.
3026          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3027          */
3028         public function flushRestrictions() {
3029                 $this->mRestrictionsLoaded = false;
3030                 $this->mTitleProtection = null;
3031         }
3032
3033         /**
3034          * Purge expired restrictions from the page_restrictions table
3035          */
3036         static function purgeExpiredRestrictions() {
3037                 if ( wfReadOnly() ) {
3038                         return;
3039                 }
3040
3041                 $method = __METHOD__;
3042                 $dbw = wfGetDB( DB_MASTER );
3043                 $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
3044                         $dbw->delete(
3045                                 'page_restrictions',
3046                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3047                                 $method
3048                         );
3049                         $dbw->delete(
3050                                 'protected_titles',
3051                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3052                                 $method
3053                         );
3054                 } );
3055         }
3056
3057         /**
3058          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3059          *
3060          * @return bool
3061          */
3062         public function hasSubpages() {
3063                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3064                         # Duh
3065                         return false;
3066                 }
3067
3068                 # We dynamically add a member variable for the purpose of this method
3069                 # alone to cache the result.  There's no point in having it hanging
3070                 # around uninitialized in every Title object; therefore we only add it
3071                 # if needed and don't declare it statically.
3072                 if ( $this->mHasSubpages === null ) {
3073                         $this->mHasSubpages = false;
3074                         $subpages = $this->getSubpages( 1 );
3075                         if ( $subpages instanceof TitleArray ) {
3076                                 $this->mHasSubpages = (bool)$subpages->count();
3077                         }
3078                 }
3079
3080                 return $this->mHasSubpages;
3081         }
3082
3083         /**
3084          * Get all subpages of this page.
3085          *
3086          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3087          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3088          *  doesn't allow subpages
3089          */
3090         public function getSubpages( $limit = -1 ) {
3091                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3092                         return array();
3093                 }
3094
3095                 $dbr = wfGetDB( DB_SLAVE );
3096                 $conds['page_namespace'] = $this->getNamespace();
3097                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3098                 $options = array();
3099                 if ( $limit > -1 ) {
3100                         $options['LIMIT'] = $limit;
3101                 }
3102                 $this->mSubpages = TitleArray::newFromResult(
3103                         $dbr->select( 'page',
3104                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3105                                 $conds,
3106                                 __METHOD__,
3107                                 $options
3108                         )
3109                 );
3110                 return $this->mSubpages;
3111         }
3112
3113         /**
3114          * Is there a version of this page in the deletion archive?
3115          *
3116          * @return int The number of archived revisions
3117          */
3118         public function isDeleted() {
3119                 if ( $this->getNamespace() < 0 ) {
3120                         $n = 0;
3121                 } else {
3122                         $dbr = wfGetDB( DB_SLAVE );
3123
3124                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3125                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3126                                 __METHOD__
3127                         );
3128                         if ( $this->getNamespace() == NS_FILE ) {
3129                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3130                                         array( 'fa_name' => $this->getDBkey() ),
3131                                         __METHOD__
3132                                 );
3133                         }
3134                 }
3135                 return (int)$n;
3136         }
3137
3138         /**
3139          * Is there a version of this page in the deletion archive?
3140          *
3141          * @return bool
3142          */
3143         public function isDeletedQuick() {
3144                 if ( $this->getNamespace() < 0 ) {
3145                         return false;
3146                 }
3147                 $dbr = wfGetDB( DB_SLAVE );
3148                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3149                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3150                         __METHOD__
3151                 );
3152                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3153                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3154                                 array( 'fa_name' => $this->getDBkey() ),
3155                                 __METHOD__
3156                         );
3157                 }
3158                 return $deleted;
3159         }
3160
3161         /**
3162          * Get the article ID for this Title from the link cache,
3163          * adding it if necessary
3164          *
3165          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3166          *  for update
3167          * @return int The ID
3168          */
3169         public function getArticleID( $flags = 0 ) {
3170                 if ( $this->getNamespace() < 0 ) {
3171                         $this->mArticleID = 0;
3172                         return $this->mArticleID;
3173                 }
3174                 $linkCache = LinkCache::singleton();
3175                 if ( $flags & self::GAID_FOR_UPDATE ) {
3176                         $oldUpdate = $linkCache->forUpdate( true );
3177                         $linkCache->clearLink( $this );
3178                         $this->mArticleID = $linkCache->addLinkObj( $this );
3179                         $linkCache->forUpdate( $oldUpdate );
3180                 } else {
3181                         if ( -1 == $this->mArticleID ) {
3182                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3183                         }
3184                 }
3185                 return $this->mArticleID;
3186         }
3187
3188         /**
3189          * Is this an article that is a redirect page?
3190          * Uses link cache, adding it if necessary
3191          *
3192          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3193          * @return bool
3194          */
3195         public function isRedirect( $flags = 0 ) {
3196                 if ( !is_null( $this->mRedirect ) ) {
3197                         return $this->mRedirect;
3198                 }
3199                 if ( !$this->getArticleID( $flags ) ) {
3200                         $this->mRedirect = false;
3201                         return $this->mRedirect;
3202                 }
3203
3204                 $linkCache = LinkCache::singleton();
3205                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3206                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3207                 if ( $cached === null ) {
3208                         # Trust LinkCache's state over our own
3209                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3210                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3211                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3212                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3213                         # LinkCache to refresh its data from the master.
3214                         $this->mRedirect = false;
3215                         return $this->mRedirect;
3216                 }
3217
3218                 $this->mRedirect = (bool)$cached;
3219
3220                 return $this->mRedirect;
3221         }
3222
3223         /**
3224          * What is the length of this page?
3225          * Uses link cache, adding it if necessary
3226          *
3227          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3228          * @return int
3229          */
3230         public function getLength( $flags = 0 ) {
3231                 if ( $this->mLength != -1 ) {
3232                         return $this->mLength;
3233                 }
3234                 if ( !$this->getArticleID( $flags ) ) {
3235                         $this->mLength = 0;
3236                         return $this->mLength;
3237                 }
3238                 $linkCache = LinkCache::singleton();
3239                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3240                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3241                 if ( $cached === null ) {
3242                         # Trust LinkCache's state over our own, as for isRedirect()
3243                         $this->mLength = 0;
3244                         return $this->mLength;
3245                 }
3246
3247                 $this->mLength = intval( $cached );
3248
3249                 return $this->mLength;
3250         }
3251
3252         /**
3253          * What is the page_latest field for this page?
3254          *
3255          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3256          * @return int Int or 0 if the page doesn't exist
3257          */
3258         public function getLatestRevID( $flags = 0 ) {
3259                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3260                         return intval( $this->mLatestID );
3261                 }
3262                 if ( !$this->getArticleID( $flags ) ) {
3263                         $this->mLatestID = 0;
3264                         return $this->mLatestID;
3265                 }
3266                 $linkCache = LinkCache::singleton();
3267                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3268                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3269                 if ( $cached === null ) {
3270                         # Trust LinkCache's state over our own, as for isRedirect()
3271                         $this->mLatestID = 0;
3272                         return $this->mLatestID;
3273                 }
3274
3275                 $this->mLatestID = intval( $cached );
3276
3277                 return $this->mLatestID;
3278         }
3279
3280         /**
3281          * This clears some fields in this object, and clears any associated
3282          * keys in the "bad links" section of the link cache.
3283          *
3284          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3285          * loading of the new page_id. It's also called from
3286          * WikiPage::doDeleteArticleReal()
3287          *
3288          * @param int $newid The new Article ID
3289          */
3290         public function resetArticleID( $newid ) {
3291                 $linkCache = LinkCache::singleton();
3292                 $linkCache->clearLink( $this );
3293
3294                 if ( $newid === false ) {
3295                         $this->mArticleID = -1;
3296                 } else {
3297                         $this->mArticleID = intval( $newid );
3298                 }
3299                 $this->mRestrictionsLoaded = false;
3300                 $this->mRestrictions = array();
3301                 $this->mOldRestrictions = false;
3302                 $this->mRedirect = null;
3303                 $this->mLength = -1;
3304                 $this->mLatestID = false;
3305                 $this->mContentModel = false;
3306                 $this->mEstimateRevisions = null;
3307                 $this->mPageLanguage = false;
3308                 $this->mDbPageLanguage = null;
3309                 $this->mIsBigDeletion = null;
3310         }
3311
3312         public static function clearCaches() {
3313                 $linkCache = LinkCache::singleton();
3314                 $linkCache->clear();
3315
3316                 $titleCache = self::getTitleCache();
3317                 $titleCache->clear();
3318         }
3319
3320         /**
3321          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3322          *
3323          * @param string $text Containing title to capitalize
3324          * @param int $ns Namespace index, defaults to NS_MAIN
3325          * @return string Containing capitalized title
3326          */
3327         public static function capitalize( $text, $ns = NS_MAIN ) {
3328                 global $wgContLang;
3329
3330                 if ( MWNamespace::isCapitalized( $ns ) ) {
3331                         return $wgContLang->ucfirst( $text );
3332                 } else {
3333                         return $text;
3334                 }
3335         }
3336
3337         /**
3338          * Secure and split - main initialisation function for this object
3339          *
3340          * Assumes that mDbkeyform has been set, and is urldecoded
3341          * and uses underscores, but not otherwise munged.  This function
3342          * removes illegal characters, splits off the interwiki and
3343          * namespace prefixes, sets the other forms, and canonicalizes
3344          * everything.
3345          *
3346          * @throws MalformedTitleException On invalid titles
3347          * @return bool True on success
3348          */
3349         private function secureAndSplit() {
3350                 # Initialisation
3351                 $this->mInterwiki = '';
3352                 $this->mFragment = '';
3353                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3354
3355                 $dbkey = $this->mDbkeyform;
3356
3357                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3358                 //        the parsing code with Title, while avoiding massive refactoring.
3359                 // @todo: get rid of secureAndSplit, refactor parsing code.
3360                 $titleParser = self::getTitleParser();
3361                 // MalformedTitleException can be thrown here
3362                 $parts = $titleParser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3363
3364                 # Fill fields
3365                 $this->setFragment( '#' . $parts['fragment'] );
3366                 $this->mInterwiki = $parts['interwiki'];
3367                 $this->mLocalInterwiki = $parts['local_interwiki'];
3368                 $this->mNamespace = $parts['namespace'];
3369                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3370
3371                 $this->mDbkeyform = $parts['dbkey'];
3372                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3373                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3374
3375                 # We already know that some pages won't be in the database!
3376                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3377                         $this->mArticleID = 0;
3378                 }
3379
3380                 return true;
3381         }
3382
3383         /**
3384          * Get an array of Title objects linking to this Title
3385          * Also stores the IDs in the link cache.
3386          *
3387          * WARNING: do not use this function on arbitrary user-supplied titles!
3388          * On heavily-used templates it will max out the memory.
3389          *
3390          * @param array $options May be FOR UPDATE
3391          * @param string $table Table name
3392          * @param string $prefix Fields prefix
3393          * @return Title[] Array of Title objects linking here
3394          */
3395         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3396                 if ( count( $options ) > 0 ) {
3397                         $db = wfGetDB( DB_MASTER );
3398                 } else {
3399                         $db = wfGetDB( DB_SLAVE );
3400                 }
3401
3402                 $res = $db->select(
3403                         array( 'page', $table ),
3404                         self::getSelectFields(),
3405                         array(
3406                                 "{$prefix}_from=page_id",
3407                                 "{$prefix}_namespace" => $this->getNamespace(),
3408                                 "{$prefix}_title" => $this->getDBkey() ),
3409                         __METHOD__,
3410                         $options
3411                 );
3412
3413                 $retVal = array();
3414                 if ( $res->numRows() ) {
3415                         $linkCache = LinkCache::singleton();
3416                         foreach ( $res as $row ) {
3417                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3418                                 if ( $titleObj ) {
3419                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3420                                         $retVal[] = $titleObj;
3421                                 }
3422                         }
3423                 }
3424                 return $retVal;
3425         }
3426
3427         /**
3428          * Get an array of Title objects using this Title as a template
3429          * Also stores the IDs in the link cache.
3430          *
3431          * WARNING: do not use this function on arbitrary user-supplied titles!
3432          * On heavily-used templates it will max out the memory.
3433          *
3434          * @param array $options May be FOR UPDATE
3435          * @return Title[] Array of Title the Title objects linking here
3436          */
3437         public function getTemplateLinksTo( $options = array() ) {
3438                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3439         }
3440
3441         /**
3442          * Get an array of Title objects linked from this Title
3443          * Also stores the IDs in the link cache.
3444          *
3445          * WARNING: do not use this function on arbitrary user-supplied titles!
3446          * On heavily-used templates it will max out the memory.
3447          *
3448          * @param array $options May be FOR UPDATE
3449          * @param string $table Table name
3450          * @param string $prefix Fields prefix
3451          * @return array Array of Title objects linking here
3452          */
3453         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3454                 $id = $this->getArticleID();
3455
3456                 # If the page doesn't exist; there can't be any link from this page
3457                 if ( !$id ) {
3458                         return array();
3459                 }
3460
3461                 if ( count( $options ) > 0 ) {
3462                         $db = wfGetDB( DB_MASTER );
3463                 } else {
3464                         $db = wfGetDB( DB_SLAVE );
3465                 }
3466
3467                 $blNamespace = "{$prefix}_namespace";
3468                 $blTitle = "{$prefix}_title";
3469
3470                 $res = $db->select(
3471                         array( $table, 'page' ),
3472                         array_merge(
3473                                 array( $blNamespace, $blTitle ),
3474                                 WikiPage::selectFields()
3475                         ),
3476                         array( "{$prefix}_from" => $id ),
3477                         __METHOD__,
3478                         $options,
3479                         array( 'page' => array(
3480                                 'LEFT JOIN',
3481                                 array( "page_namespace=$blNamespace", "page_title=$blTitle" )
3482                         ) )
3483                 );
3484
3485                 $retVal = array();
3486                 $linkCache = LinkCache::singleton();
3487                 foreach ( $res as $row ) {
3488                         if ( $row->page_id ) {
3489                                 $titleObj = Title::newFromRow( $row );
3490                         } else {
3491                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3492                                 $linkCache->addBadLinkObj( $titleObj );
3493                         }
3494                         $retVal[] = $titleObj;
3495                 }
3496
3497                 return $retVal;
3498         }
3499
3500         /**
3501          * Get an array of Title objects used on this Title as a template
3502          * Also stores the IDs in the link cache.
3503          *
3504          * WARNING: do not use this function on arbitrary user-supplied titles!
3505          * On heavily-used templates it will max out the memory.
3506          *
3507          * @param array $options May be FOR UPDATE
3508          * @return Title[] Array of Title the Title objects used here
3509          */
3510         public function getTemplateLinksFrom( $options = array() ) {
3511                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3512         }
3513
3514         /**
3515          * Get an array of Title objects referring to non-existent articles linked
3516          * from this page.
3517          *
3518          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3519          *   should use redirect table in this case).
3520          * @return Title[] Array of Title the Title objects
3521          */
3522         public function getBrokenLinksFrom() {
3523                 if ( $this->getArticleID() == 0 ) {
3524                         # All links from article ID 0 are false positives
3525                         return array();
3526                 }
3527
3528                 $dbr = wfGetDB( DB_SLAVE );
3529                 $res = $dbr->select(
3530                         array( 'page', 'pagelinks' ),
3531                         array( 'pl_namespace', 'pl_title' ),
3532                         array(
3533                                 'pl_from' => $this->getArticleID(),
3534                                 'page_namespace IS NULL'
3535                         ),
3536                         __METHOD__, array(),
3537                         array(
3538                                 'page' => array(
3539                                         'LEFT JOIN',
3540                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3541                                 )
3542                         )
3543                 );
3544
3545                 $retVal = array();
3546                 foreach ( $res as $row ) {
3547                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3548                 }
3549                 return $retVal;
3550         }
3551
3552         /**
3553          * Get a list of URLs to purge from the Squid cache when this
3554          * page changes
3555          *
3556          * @return string[] Array of String the URLs
3557          */
3558         public function getSquidURLs() {
3559                 $urls = array(
3560                         $this->getInternalURL(),
3561                         $this->getInternalURL( 'action=history' )
3562                 );
3563
3564                 $pageLang = $this->getPageLanguage();
3565                 if ( $pageLang->hasVariants() ) {
3566                         $variants = $pageLang->getVariants();
3567                         foreach ( $variants as $vCode ) {
3568                                 $urls[] = $this->getInternalURL( '', $vCode );
3569                         }
3570                 }
3571
3572                 // If we are looking at a css/js user subpage, purge the action=raw.
3573                 if ( $this->isJsSubpage() ) {
3574                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3575                 } elseif ( $this->isCssSubpage() ) {
3576                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3577                 }
3578
3579                 Hooks::run( 'TitleSquidURLs', array( $this, &$urls ) );
3580                 return $urls;
3581         }
3582
3583         /**
3584          * Purge all applicable Squid URLs
3585          */
3586         public function purgeSquid() {
3587                 global $wgUseSquid;
3588                 if ( $wgUseSquid ) {
3589                         $urls = $this->getSquidURLs();
3590                         $u = new SquidUpdate( $urls );
3591                         $u->doUpdate();
3592                 }
3593         }
3594
3595         /**
3596          * Move this page without authentication
3597          *
3598          * @deprecated since 1.25 use MovePage class instead
3599          * @param Title $nt The new page Title
3600          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3601          */
3602         public function moveNoAuth( &$nt ) {
3603                 wfDeprecated( __METHOD__, '1.25' );
3604                 return $this->moveTo( $nt, false );
3605         }
3606
3607         /**
3608          * Check whether a given move operation would be valid.
3609          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3610          *
3611          * @deprecated since 1.25, use MovePage's methods instead
3612          * @param Title $nt The new title
3613          * @param bool $auth Whether to check user permissions (uses $wgUser)
3614          * @param string $reason Is the log summary of the move, used for spam checking
3615          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3616          */
3617         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3618                 global $wgUser;
3619
3620                 if ( !( $nt instanceof Title ) ) {
3621                         // Normally we'd add this to $errors, but we'll get
3622                         // lots of syntax errors if $nt is not an object
3623                         return array( array( 'badtitletext' ) );
3624                 }
3625
3626                 $mp = new MovePage( $this, $nt );
3627                 $errors = $mp->isValidMove()->getErrorsArray();
3628                 if ( $auth ) {
3629                         $errors = wfMergeErrorArrays(
3630                                 $errors,
3631                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3632                         );
3633                 }
3634
3635                 return $errors ?: true;
3636         }
3637
3638         /**
3639          * Check if the requested move target is a valid file move target
3640          * @todo move this to MovePage
3641          * @param Title $nt Target title
3642          * @return array List of errors
3643          */
3644         protected function validateFileMoveOperation( $nt ) {
3645                 global $wgUser;
3646
3647                 $errors = array();
3648
3649                 $destFile = wfLocalFile( $nt );
3650                 $destFile->load( File::READ_LATEST );
3651                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3652                         && !$destFile->exists() && wfFindFile( $nt )
3653                 ) {
3654                         $errors[] = array( 'file-exists-sharedrepo' );
3655                 }
3656
3657                 return $errors;
3658         }
3659
3660         /**
3661          * Move a title to a new location
3662          *
3663          * @deprecated since 1.25, use the MovePage class instead
3664          * @param Title $nt The new title
3665          * @param bool $auth Indicates whether $wgUser's permissions
3666          *  should be checked
3667          * @param string $reason The reason for the move
3668          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3669          *  Ignored if the user doesn't have the suppressredirect right.
3670          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3671          */
3672         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3673                 global $wgUser;
3674                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3675                 if ( is_array( $err ) ) {
3676                         // Auto-block user's IP if the account was "hard" blocked
3677                         $wgUser->spreadAnyEditBlock();
3678                         return $err;
3679                 }
3680                 // Check suppressredirect permission
3681                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3682                         $createRedirect = true;
3683                 }
3684
3685                 $mp = new MovePage( $this, $nt );
3686                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3687                 if ( $status->isOK() ) {
3688                         return true;
3689                 } else {
3690                         return $status->getErrorsArray();
3691                 }
3692         }
3693
3694         /**
3695          * Move this page's subpages to be subpages of $nt
3696          *
3697          * @param Title $nt Move target
3698          * @param bool $auth Whether $wgUser's permissions should be checked
3699          * @param string $reason The reason for the move
3700          * @param bool $createRedirect Whether to create redirects from the old subpages to
3701          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3702          * @return array Array with old page titles as keys, and strings (new page titles) or
3703          *     arrays (errors) as values, or an error array with numeric indices if no pages
3704          *     were moved
3705          */
3706         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3707                 global $wgMaximumMovedPages;
3708                 // Check permissions
3709                 if ( !$this->userCan( 'move-subpages' ) ) {
3710                         return array( 'cant-move-subpages' );
3711                 }
3712                 // Do the source and target namespaces support subpages?
3713                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3714                         return array( 'namespace-nosubpages',
3715                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3716                 }
3717                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3718                         return array( 'namespace-nosubpages',
3719                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3720                 }
3721
3722                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3723                 $retval = array();
3724                 $count = 0;
3725                 foreach ( $subpages as $oldSubpage ) {
3726                         $count++;
3727                         if ( $count > $wgMaximumMovedPages ) {
3728                                 $retval[$oldSubpage->getPrefixedText()] =
3729                                                 array( 'movepage-max-pages',
3730                                                         $wgMaximumMovedPages );
3731                                 break;
3732                         }
3733
3734                         // We don't know whether this function was called before
3735                         // or after moving the root page, so check both
3736                         // $this and $nt
3737                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3738                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3739                         ) {
3740                                 // When moving a page to a subpage of itself,
3741                                 // don't move it twice
3742                                 continue;
3743                         }
3744                         $newPageName = preg_replace(
3745                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3746                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3747                                         $oldSubpage->getDBkey() );
3748                         if ( $oldSubpage->isTalkPage() ) {
3749                                 $newNs = $nt->getTalkPage()->getNamespace();
3750                         } else {
3751                                 $newNs = $nt->getSubjectPage()->getNamespace();
3752                         }
3753                         # Bug 14385: we need makeTitleSafe because the new page names may
3754                         # be longer than 255 characters.
3755                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3756
3757                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3758                         if ( $success === true ) {
3759                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3760                         } else {
3761                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3762                         }
3763                 }
3764                 return $retval;
3765         }
3766
3767         /**
3768          * Checks if this page is just a one-rev redirect.
3769          * Adds lock, so don't use just for light purposes.
3770          *
3771          * @return bool
3772          */
3773         public function isSingleRevRedirect() {
3774                 global $wgContentHandlerUseDB;
3775
3776                 $dbw = wfGetDB( DB_MASTER );
3777
3778                 # Is it a redirect?
3779                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
3780                 if ( $wgContentHandlerUseDB ) {
3781                         $fields[] = 'page_content_model';
3782                 }
3783
3784                 $row = $dbw->selectRow( 'page',
3785                         $fields,
3786                         $this->pageCond(),
3787                         __METHOD__,
3788                         array( 'FOR UPDATE' )
3789                 );
3790                 # Cache some fields we may want
3791                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3792                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3793                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3794                 $this->mContentModel = $row && isset( $row->page_content_model )
3795                         ? strval( $row->page_content_model )
3796                         : false;
3797
3798                 if ( !$this->mRedirect ) {
3799                         return false;
3800                 }
3801                 # Does the article have a history?
3802                 $row = $dbw->selectField( array( 'page', 'revision' ),
3803                         'rev_id',
3804                         array( 'page_namespace' => $this->getNamespace(),
3805                                 'page_title' => $this->getDBkey(),
3806                                 'page_id=rev_page',
3807                                 'page_latest != rev_id'
3808                         ),
3809                         __METHOD__,
3810                         array( 'FOR UPDATE' )
3811                 );
3812                 # Return true if there was no history
3813                 return ( $row === false );
3814         }
3815
3816         /**
3817          * Checks if $this can be moved to a given Title
3818          * - Selects for update, so don't call it unless you mean business
3819          *
3820          * @deprecated since 1.25, use MovePage's methods instead
3821          * @param Title $nt The new title to check
3822          * @return bool
3823          */
3824         public function isValidMoveTarget( $nt ) {
3825                 # Is it an existing file?
3826                 if ( $nt->getNamespace() == NS_FILE ) {
3827                         $file = wfLocalFile( $nt );
3828                         $file->load( File::READ_LATEST );
3829                         if ( $file->exists() ) {
3830                                 wfDebug( __METHOD__ . ": file exists\n" );
3831                                 return false;
3832                         }
3833                 }
3834                 # Is it a redirect with no history?
3835                 if ( !$nt->isSingleRevRedirect() ) {
3836                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3837                         return false;
3838                 }
3839                 # Get the article text
3840                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3841                 if ( !is_object( $rev ) ) {
3842                         return false;
3843                 }
3844                 $content = $rev->getContent();
3845                 # Does the redirect point to the source?
3846                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3847                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3848
3849                 if ( $redirTitle ) {
3850                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3851                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3852                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3853                                 return false;
3854                         } else {
3855                                 return true;
3856                         }
3857                 } else {
3858                         # Fail safe (not a redirect after all. strange.)
3859                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3860                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3861                         return false;
3862                 }
3863         }
3864
3865         /**
3866          * Get categories to which this Title belongs and return an array of
3867          * categories' names.
3868          *
3869          * @return array Array of parents in the form:
3870          *        $parent => $currentarticle
3871          */
3872         public function getParentCategories() {
3873                 global $wgContLang;
3874
3875                 $data = array();
3876
3877                 $titleKey = $this->getArticleID();
3878
3879                 if ( $titleKey === 0 ) {
3880                         return $data;
3881                 }
3882
3883                 $dbr = wfGetDB( DB_SLAVE );
3884
3885                 $res = $dbr->select(
3886                         'categorylinks',
3887                         'cl_to',
3888                         array( 'cl_from' => $titleKey ),
3889                         __METHOD__
3890                 );
3891
3892                 if ( $res->numRows() > 0 ) {
3893                         foreach ( $res as $row ) {
3894                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3895                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3896                         }
3897                 }
3898                 return $data;
3899         }
3900
3901         /**
3902          * Get a tree of parent categories
3903          *
3904          * @param array $children Array with the children in the keys, to check for circular refs
3905          * @return array Tree of parent categories
3906          */
3907         public function getParentCategoryTree( $children = array() ) {
3908                 $stack = array();
3909                 $parents = $this->getParentCategories();
3910
3911                 if ( $parents ) {
3912                         foreach ( $parents as $parent => $current ) {
3913                                 if ( array_key_exists( $parent, $children ) ) {
3914                                         # Circular reference
3915                                         $stack[$parent] = array();
3916                                 } else {
3917                                         $nt = Title::newFromText( $parent );
3918                                         if ( $nt ) {
3919                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
3920                                         }
3921                                 }
3922                         }
3923                 }
3924
3925                 return $stack;
3926         }
3927
3928         /**
3929          * Get an associative array for selecting this title from
3930          * the "page" table
3931          *
3932          * @return array Array suitable for the $where parameter of DB::select()
3933          */
3934         public function pageCond() {
3935                 if ( $this->mArticleID > 0 ) {
3936                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3937                         return array( 'page_id' => $this->mArticleID );
3938                 } else {
3939                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
3940                 }
3941         }
3942
3943         /**
3944          * Get the revision ID of the previous revision
3945          *
3946          * @param int $revId Revision ID. Get the revision that was before this one.
3947          * @param int $flags Title::GAID_FOR_UPDATE
3948          * @return int|bool Old revision ID, or false if none exists
3949          */
3950         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3951                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3952                 $revId = $db->selectField( 'revision', 'rev_id',
3953                         array(
3954                                 'rev_page' => $this->getArticleID( $flags ),
3955                                 'rev_id < ' . intval( $revId )
3956                         ),
3957                         __METHOD__,
3958                         array( 'ORDER BY' => 'rev_id DESC' )
3959                 );
3960
3961                 if ( $revId === false ) {
3962                         return false;
3963                 } else {
3964                         return intval( $revId );
3965                 }
3966         }
3967
3968         /**
3969          * Get the revision ID of the next revision
3970          *
3971          * @param int $revId Revision ID. Get the revision that was after this one.
3972          * @param int $flags Title::GAID_FOR_UPDATE
3973          * @return int|bool Next revision ID, or false if none exists
3974          */
3975         public function getNextRevisionID( $revId, $flags = 0 ) {
3976                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3977                 $revId = $db->selectField( 'revision', 'rev_id',
3978                         array(
3979                                 'rev_page' => $this->getArticleID( $flags ),
3980                                 'rev_id > ' . intval( $revId )
3981                         ),
3982                         __METHOD__,
3983                         array( 'ORDER BY' => 'rev_id' )
3984                 );
3985
3986                 if ( $revId === false ) {
3987                         return false;
3988                 } else {
3989                         return intval( $revId );
3990                 }
3991         }
3992
3993         /**
3994          * Get the first revision of the page
3995          *
3996          * @param int $flags Title::GAID_FOR_UPDATE
3997          * @return Revision|null If page doesn't exist
3998          */
3999         public function getFirstRevision( $flags = 0 ) {
4000                 $pageId = $this->getArticleID( $flags );
4001                 if ( $pageId ) {
4002                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4003                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4004                                 array( 'rev_page' => $pageId ),
4005                                 __METHOD__,
4006                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4007                         );
4008                         if ( $row ) {
4009                                 return new Revision( $row );
4010                         }
4011                 }
4012                 return null;
4013         }
4014
4015         /**
4016          * Get the oldest revision timestamp of this page
4017          *
4018          * @param int $flags Title::GAID_FOR_UPDATE
4019          * @return string MW timestamp
4020          */
4021         public function getEarliestRevTime( $flags = 0 ) {
4022                 $rev = $this->getFirstRevision( $flags );
4023                 return $rev ? $rev->getTimestamp() : null;
4024         }
4025
4026         /**
4027          * Check if this is a new page
4028          *
4029          * @return bool
4030          */
4031         public function isNewPage() {
4032                 $dbr = wfGetDB( DB_SLAVE );
4033                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4034         }
4035
4036         /**
4037          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4038          *
4039          * @return bool
4040          */
4041         public function isBigDeletion() {
4042                 global $wgDeleteRevisionsLimit;
4043
4044                 if ( !$wgDeleteRevisionsLimit ) {
4045                         return false;
4046                 }
4047
4048                 if ( $this->mIsBigDeletion === null ) {
4049                         $dbr = wfGetDB( DB_SLAVE );
4050
4051                         $revCount = $dbr->selectRowCount(
4052                                 'revision',
4053                                 '1',
4054                                 array( 'rev_page' => $this->getArticleID() ),
4055                                 __METHOD__,
4056                                 array( 'LIMIT' => $wgDeleteRevisionsLimit + 1 )
4057                         );
4058
4059                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4060                 }
4061
4062                 return $this->mIsBigDeletion;
4063         }
4064
4065         /**
4066          * Get the approximate revision count of this page.
4067          *
4068          * @return int
4069          */
4070         public function estimateRevisionCount() {
4071                 if ( !$this->exists() ) {
4072                         return 0;
4073                 }
4074
4075                 if ( $this->mEstimateRevisions === null ) {
4076                         $dbr = wfGetDB( DB_SLAVE );
4077                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4078                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4079                 }
4080
4081                 return $this->mEstimateRevisions;
4082         }
4083
4084         /**
4085          * Get the number of revisions between the given revision.
4086          * Used for diffs and other things that really need it.
4087          *
4088          * @param int|Revision $old Old revision or rev ID (first before range)
4089          * @param int|Revision $new New revision or rev ID (first after range)
4090          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4091          * @return int Number of revisions between these revisions.
4092          */
4093         public function countRevisionsBetween( $old, $new, $max = null ) {
4094                 if ( !( $old instanceof Revision ) ) {
4095                         $old = Revision::newFromTitle( $this, (int)$old );
4096                 }
4097                 if ( !( $new instanceof Revision ) ) {
4098                         $new = Revision::newFromTitle( $this, (int)$new );
4099                 }
4100                 if ( !$old || !$new ) {
4101                         return 0; // nothing to compare
4102                 }
4103                 $dbr = wfGetDB( DB_SLAVE );
4104                 $conds = array(
4105                         'rev_page' => $this->getArticleID(),
4106                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4107                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4108                 );
4109                 if ( $max !== null ) {
4110                         return $dbr->selectRowCount( 'revision', '1',
4111                                 $conds,
4112                                 __METHOD__,
4113                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4114                         );
4115                 } else {
4116                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4117                 }
4118         }
4119
4120         /**
4121          * Get the authors between the given revisions or revision IDs.
4122          * Used for diffs and other things that really need it.
4123          *
4124          * @since 1.23
4125          *
4126          * @param int|Revision $old Old revision or rev ID (first before range by default)
4127          * @param int|Revision $new New revision or rev ID (first after range by default)
4128          * @param int $limit Maximum number of authors
4129          * @param string|array $options (Optional): Single option, or an array of options:
4130          *     'include_old' Include $old in the range; $new is excluded.
4131          *     'include_new' Include $new in the range; $old is excluded.
4132          *     'include_both' Include both $old and $new in the range.
4133          *     Unknown option values are ignored.
4134          * @return array|null Names of revision authors in the range; null if not both revisions exist
4135          */
4136         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4137                 if ( !( $old instanceof Revision ) ) {
4138                         $old = Revision::newFromTitle( $this, (int)$old );
4139                 }
4140                 if ( !( $new instanceof Revision ) ) {
4141                         $new = Revision::newFromTitle( $this, (int)$new );
4142                 }
4143                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4144                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4145                 // in the sanity check below?
4146                 if ( !$old || !$new ) {
4147                         return null; // nothing to compare
4148                 }
4149                 $authors = array();
4150                 $old_cmp = '>';
4151                 $new_cmp = '<';
4152                 $options = (array)$options;
4153                 if ( in_array( 'include_old', $options ) ) {
4154                         $old_cmp = '>=';
4155                 }
4156                 if ( in_array( 'include_new', $options ) ) {
4157                         $new_cmp = '<=';
4158                 }
4159                 if ( in_array( 'include_both', $options ) ) {
4160                         $old_cmp = '>=';
4161                         $new_cmp = '<=';
4162                 }
4163                 // No DB query needed if $old and $new are the same or successive revisions:
4164                 if ( $old->getId() === $new->getId() ) {
4165                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4166                                 array() :
4167                                 array( $old->getUserText( Revision::RAW ) );
4168                 } elseif ( $old->getId() === $new->getParentId() ) {
4169                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4170                                 $authors[] = $old->getUserText( Revision::RAW );
4171                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4172                                         $authors[] = $new->getUserText( Revision::RAW );
4173                                 }
4174                         } elseif ( $old_cmp === '>=' ) {
4175                                 $authors[] = $old->getUserText( Revision::RAW );
4176                         } elseif ( $new_cmp === '<=' ) {
4177                                 $authors[] = $new->getUserText( Revision::RAW );
4178                         }
4179                         return $authors;
4180                 }
4181                 $dbr = wfGetDB( DB_SLAVE );
4182                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4183                         array(
4184                                 'rev_page' => $this->getArticleID(),
4185                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4186                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4187                         ), __METHOD__,
4188                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4189                 );
4190                 foreach ( $res as $row ) {
4191                         $authors[] = $row->rev_user_text;
4192                 }
4193                 return $authors;
4194         }
4195
4196         /**
4197          * Get the number of authors between the given revisions or revision IDs.
4198          * Used for diffs and other things that really need it.
4199          *
4200          * @param int|Revision $old Old revision or rev ID (first before range by default)
4201          * @param int|Revision $new New revision or rev ID (first after range by default)
4202          * @param int $limit Maximum number of authors
4203          * @param string|array $options (Optional): Single option, or an array of options:
4204          *     'include_old' Include $old in the range; $new is excluded.
4205          *     'include_new' Include $new in the range; $old is excluded.
4206          *     'include_both' Include both $old and $new in the range.
4207          *     Unknown option values are ignored.
4208          * @return int Number of revision authors in the range; zero if not both revisions exist
4209          */
4210         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4211                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4212                 return $authors ? count( $authors ) : 0;
4213         }
4214
4215         /**
4216          * Compare with another title.
4217          *
4218          * @param Title $title
4219          * @return bool
4220          */
4221         public function equals( Title $title ) {
4222                 // Note: === is necessary for proper matching of number-like titles.
4223                 return $this->getInterwiki() === $title->getInterwiki()
4224                         && $this->getNamespace() == $title->getNamespace()
4225                         && $this->getDBkey() === $title->getDBkey();
4226         }
4227
4228         /**
4229          * Check if this title is a subpage of another title
4230          *
4231          * @param Title $title
4232          * @return bool
4233          */
4234         public function isSubpageOf( Title $title ) {
4235                 return $this->getInterwiki() === $title->getInterwiki()
4236                         && $this->getNamespace() == $title->getNamespace()
4237                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4238         }
4239
4240         /**
4241          * Check if page exists.  For historical reasons, this function simply
4242          * checks for the existence of the title in the page table, and will
4243          * thus return false for interwiki links, special pages and the like.
4244          * If you want to know if a title can be meaningfully viewed, you should
4245          * probably call the isKnown() method instead.
4246          *
4247          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4248          *   from master/for update
4249          * @return bool
4250          */
4251         public function exists( $flags = 0 ) {
4252                 $exists = $this->getArticleID( $flags ) != 0;
4253                 Hooks::run( 'TitleExists', array( $this, &$exists ) );
4254                 return $exists;
4255         }
4256
4257         /**
4258          * Should links to this title be shown as potentially viewable (i.e. as
4259          * "bluelinks"), even if there's no record by this title in the page
4260          * table?
4261          *
4262          * This function is semi-deprecated for public use, as well as somewhat
4263          * misleadingly named.  You probably just want to call isKnown(), which
4264          * calls this function internally.
4265          *
4266          * (ISSUE: Most of these checks are cheap, but the file existence check
4267          * can potentially be quite expensive.  Including it here fixes a lot of
4268          * existing code, but we might want to add an optional parameter to skip
4269          * it and any other expensive checks.)
4270          *
4271          * @return bool
4272          */
4273         public function isAlwaysKnown() {
4274                 $isKnown = null;
4275
4276                 /**
4277                  * Allows overriding default behavior for determining if a page exists.
4278                  * If $isKnown is kept as null, regular checks happen. If it's
4279                  * a boolean, this value is returned by the isKnown method.
4280                  *
4281                  * @since 1.20
4282                  *
4283                  * @param Title $title
4284                  * @param bool|null $isKnown
4285                  */
4286                 Hooks::run( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4287
4288                 if ( !is_null( $isKnown ) ) {
4289                         return $isKnown;
4290                 }
4291
4292                 if ( $this->isExternal() ) {
4293                         return true;  // any interwiki link might be viewable, for all we know
4294                 }
4295
4296                 switch ( $this->mNamespace ) {
4297                         case NS_MEDIA:
4298                         case NS_FILE:
4299                                 // file exists, possibly in a foreign repo
4300                                 return (bool)wfFindFile( $this );
4301                         case NS_SPECIAL:
4302                                 // valid special page
4303                                 return SpecialPageFactory::exists( $this->getDBkey() );
4304                         case NS_MAIN:
4305                                 // selflink, possibly with fragment
4306                                 return $this->mDbkeyform == '';
4307                         case NS_MEDIAWIKI:
4308                                 // known system message
4309                                 return $this->hasSourceText() !== false;
4310                         default:
4311                                 return false;
4312                 }
4313         }
4314
4315         /**
4316          * Does this title refer to a page that can (or might) be meaningfully
4317          * viewed?  In particular, this function may be used to determine if
4318          * links to the title should be rendered as "bluelinks" (as opposed to
4319          * "redlinks" to non-existent pages).
4320          * Adding something else to this function will cause inconsistency
4321          * since LinkHolderArray calls isAlwaysKnown() and does its own
4322          * page existence check.
4323          *
4324          * @return bool
4325          */
4326         public function isKnown() {
4327                 return $this->isAlwaysKnown() || $this->exists();
4328         }
4329
4330         /**
4331          * Does this page have source text?
4332          *
4333          * @return bool
4334          */
4335         public function hasSourceText() {
4336                 if ( $this->exists() ) {
4337                         return true;
4338                 }
4339
4340                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4341                         // If the page doesn't exist but is a known system message, default
4342                         // message content will be displayed, same for language subpages-
4343                         // Use always content language to avoid loading hundreds of languages
4344                         // to get the link color.
4345                         global $wgContLang;
4346                         list( $name, ) = MessageCache::singleton()->figureMessage(
4347                                 $wgContLang->lcfirst( $this->getText() )
4348                         );
4349                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4350                         return $message->exists();
4351                 }
4352
4353                 return false;
4354         }
4355
4356         /**
4357          * Get the default message text or false if the message doesn't exist
4358          *
4359          * @return string|bool
4360          */
4361         public function getDefaultMessageText() {
4362                 global $wgContLang;
4363
4364                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4365                         return false;
4366                 }
4367
4368                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4369                         $wgContLang->lcfirst( $this->getText() )
4370                 );
4371                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4372
4373                 if ( $message->exists() ) {
4374                         return $message->plain();
4375                 } else {
4376                         return false;
4377                 }
4378         }
4379
4380         /**
4381          * Updates page_touched for this page; called from LinksUpdate.php
4382          *
4383          * @param integer $purgeTime TS_MW timestamp [optional]
4384          * @return bool True if the update succeeded
4385          */
4386         public function invalidateCache( $purgeTime = null ) {
4387                 if ( wfReadOnly() ) {
4388                         return false;
4389                 }
4390
4391                 if ( $this->mArticleID === 0 ) {
4392                         return true; // avoid gap locking if we know it's not there
4393                 }
4394
4395                 $method = __METHOD__;
4396                 $dbw = wfGetDB( DB_MASTER );
4397                 $conds = $this->pageCond();
4398                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method, $purgeTime ) {
4399                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4400
4401                         $dbw->update(
4402                                 'page',
4403                                 array( 'page_touched' => $dbTimestamp ),
4404                                 $conds + array( 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ),
4405                                 $method
4406                         );
4407                 } );
4408
4409                 return true;
4410         }
4411
4412         /**
4413          * Update page_touched timestamps and send squid purge messages for
4414          * pages linking to this title. May be sent to the job queue depending
4415          * on the number of links. Typically called on create and delete.
4416          */
4417         public function touchLinks() {
4418                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4419                 $u->doUpdate();
4420
4421                 if ( $this->getNamespace() == NS_CATEGORY ) {
4422                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4423                         $u->doUpdate();
4424                 }
4425         }
4426
4427         /**
4428          * Get the last touched timestamp
4429          *
4430          * @param DatabaseBase $db Optional db
4431          * @return string Last-touched timestamp
4432          */
4433         public function getTouched( $db = null ) {
4434                 if ( $db === null ) {
4435                         $db = wfGetDB( DB_SLAVE );
4436                 }
4437                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4438                 return $touched;
4439         }
4440
4441         /**
4442          * Get the timestamp when this page was updated since the user last saw it.
4443          *
4444          * @param User $user
4445          * @return string|null
4446          */
4447         public function getNotificationTimestamp( $user = null ) {
4448                 global $wgUser;
4449
4450                 // Assume current user if none given
4451                 if ( !$user ) {
4452                         $user = $wgUser;
4453                 }
4454                 // Check cache first
4455                 $uid = $user->getId();
4456                 if ( !$uid ) {
4457                         return false;
4458                 }
4459                 // avoid isset here, as it'll return false for null entries
4460                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4461                         return $this->mNotificationTimestamp[$uid];
4462                 }
4463                 // Don't cache too much!
4464                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4465                         $this->mNotificationTimestamp = array();
4466                 }
4467
4468                 $watchedItem = WatchedItem::fromUserTitle( $user, $this );
4469                 $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4470
4471                 return $this->mNotificationTimestamp[$uid];
4472         }
4473
4474         /**
4475          * Generate strings used for xml 'id' names in monobook tabs
4476          *
4477          * @param string $prepend Defaults to 'nstab-'
4478          * @return string XML 'id' name
4479          */
4480         public function getNamespaceKey( $prepend = 'nstab-' ) {
4481                 global $wgContLang;
4482                 // Gets the subject namespace if this title
4483                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4484                 // Checks if canonical namespace name exists for namespace
4485                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4486                         // Uses canonical namespace name
4487                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4488                 } else {
4489                         // Uses text of namespace
4490                         $namespaceKey = $this->getSubjectNsText();
4491                 }
4492                 // Makes namespace key lowercase
4493                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4494                 // Uses main
4495                 if ( $namespaceKey == '' ) {
4496                         $namespaceKey = 'main';
4497                 }
4498                 // Changes file to image for backwards compatibility
4499                 if ( $namespaceKey == 'file' ) {
4500                         $namespaceKey = 'image';
4501                 }
4502                 return $prepend . $namespaceKey;
4503         }
4504
4505         /**
4506          * Get all extant redirects to this Title
4507          *
4508          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4509          * @return Title[] Array of Title redirects to this title
4510          */
4511         public function getRedirectsHere( $ns = null ) {
4512                 $redirs = array();
4513
4514                 $dbr = wfGetDB( DB_SLAVE );
4515                 $where = array(
4516                         'rd_namespace' => $this->getNamespace(),
4517                         'rd_title' => $this->getDBkey(),
4518                         'rd_from = page_id'
4519                 );
4520                 if ( $this->isExternal() ) {
4521                         $where['rd_interwiki'] = $this->getInterwiki();
4522                 } else {
4523                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4524                 }
4525                 if ( !is_null( $ns ) ) {
4526                         $where['page_namespace'] = $ns;
4527                 }
4528
4529                 $res = $dbr->select(
4530                         array( 'redirect', 'page' ),
4531                         array( 'page_namespace', 'page_title' ),
4532                         $where,
4533                         __METHOD__
4534                 );
4535
4536                 foreach ( $res as $row ) {
4537                         $redirs[] = self::newFromRow( $row );
4538                 }
4539                 return $redirs;
4540         }
4541
4542         /**
4543          * Check if this Title is a valid redirect target
4544          *
4545          * @return bool
4546          */
4547         public function isValidRedirectTarget() {
4548                 global $wgInvalidRedirectTargets;
4549
4550                 if ( $this->isSpecialPage() ) {
4551                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4552                         if ( $this->isSpecial( 'Userlogout' ) ) {
4553                                 return false;
4554                         }
4555
4556                         foreach ( $wgInvalidRedirectTargets as $target ) {
4557                                 if ( $this->isSpecial( $target ) ) {
4558                                         return false;
4559                                 }
4560                         }
4561                 }
4562
4563                 return true;
4564         }
4565
4566         /**
4567          * Get a backlink cache object
4568          *
4569          * @return BacklinkCache
4570          */
4571         public function getBacklinkCache() {
4572                 return BacklinkCache::get( $this );
4573         }
4574
4575         /**
4576          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4577          *
4578          * @return bool
4579          */
4580         public function canUseNoindex() {
4581                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4582
4583                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4584                         ? $wgContentNamespaces
4585                         : $wgExemptFromUserRobotsControl;
4586
4587                 return !in_array( $this->mNamespace, $bannedNamespaces );
4588
4589         }
4590
4591         /**
4592          * Returns the raw sort key to be used for categories, with the specified
4593          * prefix.  This will be fed to Collation::getSortKey() to get a
4594          * binary sortkey that can be used for actual sorting.
4595          *
4596          * @param string $prefix The prefix to be used, specified using
4597          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4598          *   prefix.
4599          * @return string
4600          */
4601         public function getCategorySortkey( $prefix = '' ) {
4602                 $unprefixed = $this->getText();
4603
4604                 // Anything that uses this hook should only depend
4605                 // on the Title object passed in, and should probably
4606                 // tell the users to run updateCollations.php --force
4607                 // in order to re-sort existing category relations.
4608                 Hooks::run( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4609                 if ( $prefix !== '' ) {
4610                         # Separate with a line feed, so the unprefixed part is only used as
4611                         # a tiebreaker when two pages have the exact same prefix.
4612                         # In UCA, tab is the only character that can sort above LF
4613                         # so we strip both of them from the original prefix.
4614                         $prefix = strtr( $prefix, "\n\t", '  ' );
4615                         return "$prefix\n$unprefixed";
4616                 }
4617                 return $unprefixed;
4618         }
4619
4620         /**
4621          * Get the language in which the content of this page is written in
4622          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4623          * e.g. $wgLang (such as special pages, which are in the user language).
4624          *
4625          * @since 1.18
4626          * @return Language
4627          */
4628         public function getPageLanguage() {
4629                 global $wgLang, $wgLanguageCode;
4630                 if ( $this->isSpecialPage() ) {
4631                         // special pages are in the user language
4632                         return $wgLang;
4633                 }
4634
4635                 // Checking if DB language is set
4636                 if ( $this->mDbPageLanguage ) {
4637                         return wfGetLangObj( $this->mDbPageLanguage );
4638                 }
4639
4640                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4641                         // Note that this may depend on user settings, so the cache should
4642                         // be only per-request.
4643                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4644                         // content to determine the page language!
4645                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4646                         // tests.
4647                         $contentHandler = ContentHandler::getForTitle( $this );
4648                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4649                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4650                 } else {
4651                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4652                 }
4653
4654                 return $langObj;
4655         }
4656
4657         /**
4658          * Get the language in which the content of this page is written when
4659          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4660          * e.g. $wgLang (such as special pages, which are in the user language).
4661          *
4662          * @since 1.20
4663          * @return Language
4664          */
4665         public function getPageViewLanguage() {
4666                 global $wgLang;
4667
4668                 if ( $this->isSpecialPage() ) {
4669                         // If the user chooses a variant, the content is actually
4670                         // in a language whose code is the variant code.
4671                         $variant = $wgLang->getPreferredVariant();
4672                         if ( $wgLang->getCode() !== $variant ) {
4673                                 return Language::factory( $variant );
4674                         }
4675
4676                         return $wgLang;
4677                 }
4678
4679                 // @note Can't be cached persistently, depends on user settings.
4680                 // @note ContentHandler::getPageViewLanguage() may need to load the
4681                 //   content to determine the page language!
4682                 $contentHandler = ContentHandler::getForTitle( $this );
4683                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4684                 return $pageLang;
4685         }
4686
4687         /**
4688          * Get a list of rendered edit notices for this page.
4689          *
4690          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4691          * they will already be wrapped in paragraphs.
4692          *
4693          * @since 1.21
4694          * @param int $oldid Revision ID that's being edited
4695          * @return array
4696          */
4697         public function getEditNotices( $oldid = 0 ) {
4698                 $notices = array();
4699
4700                 // Optional notice for the entire namespace
4701                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4702                 $msg = wfMessage( $editnotice_ns );
4703                 if ( $msg->exists() ) {
4704                         $html = $msg->parseAsBlock();
4705                         // Edit notices may have complex logic, but output nothing (T91715)
4706                         if ( trim( $html ) !== '' ) {
4707                                 $notices[$editnotice_ns] = Html::rawElement(
4708                                         'div',
4709                                         array( 'class' => array(
4710                                                 'mw-editnotice',
4711                                                 'mw-editnotice-namespace',
4712                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4713                                         ) ),
4714                                         $html
4715                                 );
4716                         }
4717                 }
4718
4719                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4720                         // Optional notice for page itself and any parent page
4721                         $parts = explode( '/', $this->getDBkey() );
4722                         $editnotice_base = $editnotice_ns;
4723                         while ( count( $parts ) > 0 ) {
4724                                 $editnotice_base .= '-' . array_shift( $parts );
4725                                 $msg = wfMessage( $editnotice_base );
4726                                 if ( $msg->exists() ) {
4727                                         $html = $msg->parseAsBlock();
4728                                         if ( trim( $html ) !== '' ) {
4729                                                 $notices[$editnotice_base] = Html::rawElement(
4730                                                         'div',
4731                                                         array( 'class' => array(
4732                                                                 'mw-editnotice',
4733                                                                 'mw-editnotice-base',
4734                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4735                                                         ) ),
4736                                                         $html
4737                                                 );
4738                                         }
4739                                 }
4740                         }
4741                 } else {
4742                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4743                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4744                         $msg = wfMessage( $editnoticeText );
4745                         if ( $msg->exists() ) {
4746                                 $html = $msg->parseAsBlock();
4747                                 if ( trim( $html ) !== '' ) {
4748                                         $notices[$editnoticeText] = Html::rawElement(
4749                                                 'div',
4750                                                 array( 'class' => array(
4751                                                         'mw-editnotice',
4752                                                         'mw-editnotice-page',
4753                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4754                                                 ) ),
4755                                                 $html
4756                                         );
4757                                 }
4758                         }
4759                 }
4760
4761                 Hooks::run( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4762                 return $notices;
4763         }
4764
4765         /**
4766          * @return array
4767          */
4768         public function __sleep() {
4769                 return array(
4770                         'mNamespace',
4771                         'mDbkeyform',
4772                         'mFragment',
4773                         'mInterwiki',
4774                         'mLocalInterwiki',
4775                         'mUserCaseDBKey',
4776                         'mDefaultNamespace',
4777                 );
4778         }
4779
4780         public function __wakeup() {
4781                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4782                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4783                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4784         }
4785
4786 }