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 implements LinkTarget {
  34         /** @var HashBagOStuff */
  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         /** @var int The page length, 0 for special pages */
 134         protected $mLength = -1;
 135
 136         /** @var null Is the article at this title a redirect? */
 137         public $mRedirect = null;
 138
 139         /** @var array Associative array of user ID -> timestamp/false */
 140         private $mNotificationTimestamp = array();
 141
 142         /** @var bool Whether a page has any subpages */
 143         private $mHasSubpages;
 144
 145         /** @var bool The (string) language code of the page's language and content code. */
 146         private $mPageLanguage = false;
 147
 148         /** @var string The page language code from the database */
 149         private $mDbPageLanguage = null;
 150
 151         /** @var TitleValue A corresponding TitleValue object */
 152         private $mTitleValue = null;
 153
 154         /** @var bool Would deleting this page be a big deletion? */
 155         private $mIsBigDeletion = null;
 156         // @}
 157
 158         /**
 159          * B/C kludge: provide a TitleParser for use by Title.
 160          * Ideally, Title would have no methods that need this.
 161          * Avoid usage of this singleton by using TitleValue
 162          * and the associated services when possible.
 163          *
 164          * @return TitleParser
 165          */
 166         private static function getTitleParser() {
 167                 global $wgContLang, $wgLocalInterwikis;
 168
 169                 static $titleCodec = null;
 170                 static $titleCodecFingerprint = null;
 171
 172                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 173                 // make sure we are using the right one. To detect changes over the course
 174                 // of a request, we remember a fingerprint of the config used to create the
 175                 // codec singleton, and re-create it if the fingerprint doesn't match.
 176                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . join( '+', $wgLocalInterwikis );
 177
 178                 if ( $fingerprint !== $titleCodecFingerprint ) {
 179                         $titleCodec = null;
 180                 }
 181
 182                 if ( !$titleCodec ) {
 183                         $titleCodec = new MediaWikiTitleCodec(
 184                                 $wgContLang,
 185                                 GenderCache::singleton(),
 186                                 $wgLocalInterwikis
 187                         );
 188                         $titleCodecFingerprint = $fingerprint;
 189                 }
 190
 191                 return $titleCodec;
 192         }
 193
 194         /**
 195          * B/C kludge: provide a TitleParser for use by Title.
 196          * Ideally, Title would have no methods that need this.
 197          * Avoid usage of this singleton by using TitleValue
 198          * and the associated services when possible.
 199          *
 200          * @return TitleFormatter
 201          */
 202         private static function getTitleFormatter() {
 203                 // NOTE: we know that getTitleParser() returns a MediaWikiTitleCodec,
 204                 //      which implements TitleFormatter.
 205                 return self::getTitleParser();
 206         }
 207
 208         function __construct() {
 209         }
 210
 211         /**
 212          * Create a new Title from a prefixed DB key
 213          *
 214          * @param string $key The database key, which has underscores
 215          *      instead of spaces, possibly including namespace and
 216          *      interwiki prefixes
 217          * @return Title|null Title, or null on an error
 218          */
 219         public static function newFromDBkey( $key ) {
 220                 $t = new Title();
 221                 $t->mDbkeyform = $key;
 222
 223                 try {
 224                         $t->secureAndSplit();
 225                         return $t;
 226                 } catch ( MalformedTitleException $ex ) {
 227                         return null;
 228                 }
 229         }
 230
 231         /**
 232          * Create a new Title from a TitleValue
 233          *
 234          * @param TitleValue $titleValue Assumed to be safe.
 235          *
 236          * @return Title
 237          */
 238         public static function newFromTitleValue( TitleValue $titleValue ) {
 239                 return self::newFromLinkTarget( $titleValue );
 240         }
 241
 242         /**
 243          * Create a new Title from a LinkTarget
 244          *
 245          * @param LinkTarget $linkTarget Assumed to be safe.
 246          *
 247          * @return Title
 248          */
 249         public static function newFromLinkTarget( LinkTarget $linkTarget ) {
 250                 return self::makeTitle(
 251                         $linkTarget->getNamespace(),
 252                         $linkTarget->getText(),
 253                         $linkTarget->getFragment() );
 254         }
 255
 256         /**
 257          * Create a new Title from text, such as what one would find in a link. De-
 258          * codes any HTML entities in the text.
 259          *
 260          * @param string|int|null $text The link text; spaces, prefixes, and an
 261          *   initial ':' indicating the main namespace are accepted.
 262          * @param int $defaultNamespace The namespace to use if none is specified
 263          *   by a prefix.  If you want to force a specific namespace even if
 264          *   $text might begin with a namespace prefix, use makeTitle() or
 265          *   makeTitleSafe().
 266          * @throws InvalidArgumentException
 267          * @return Title|null Title or null on an error.
 268          */
 269         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 270                 if ( is_object( $text ) ) {
 271                         throw new InvalidArgumentException( '$text must be a string.' );
 272                 }
 273                 // DWIM: Integers can be passed in here when page titles are used as array keys.
 274                 if ( $text !== null && !is_string( $text ) && !is_int( $text ) ) {
 275                         wfDebugLog( 'T76305', wfGetAllCallers( 5 ) );
 276                         return null;
 277                 }
 278                 if ( $text === null ) {
 279                         return null;
 280                 }
 281
 282                 try {
 283                         return Title::newFromTextThrow( strval( $text ), $defaultNamespace );
 284                 } catch ( MalformedTitleException $ex ) {
 285                         return null;
 286                 }
 287         }
 288
 289         /**
 290          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 291          * rather than returning null.
 292          *
 293          * The exception subclasses encode detailed information about why the title is invalid.
 294          *
 295          * @see Title::newFromText
 296          *
 297          * @since 1.25
 298          * @param string $text Title text to check
 299          * @param int $defaultNamespace
 300          * @throws MalformedTitleException If the title is invalid
 301          * @return Title
 302          */
 303         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 304                 if ( is_object( $text ) ) {
 305                         throw new MWException( '$text must be a string, given an object' );
 306                 }
 307
 308                 $titleCache = self::getTitleCache();
 309
 310                 // Wiki pages often contain multiple links to the same page.
 311                 // Title normalization and parsing can become expensive on pages with many
 312                 // links, so we can save a little time by caching them.
 313                 // In theory these are value objects and won't get changed...
 314                 if ( $defaultNamespace == NS_MAIN ) {
 315                         $t = $titleCache->get( $text );
 316                         if ( $t ) {
 317                                 return $t;
 318                         }
 319                 }
 320
 321                 // Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 322                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 323
 324                 $t = new Title();
 325                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 326                 $t->mDefaultNamespace = intval( $defaultNamespace );
 327
 328                 $t->secureAndSplit();
 329                 if ( $defaultNamespace == NS_MAIN ) {
 330                         $titleCache->set( $text, $t );
 331                 }
 332                 return $t;
 333         }
 334
 335         /**
 336          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 337          *
 338          * Example of wrong and broken code:
 339          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 340          *
 341          * Example of right code:
 342          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 343          *
 344          * Create a new Title from URL-encoded text. Ensures that
 345          * the given title's length does not exceed the maximum.
 346          *
 347          * @param string $url The title, as might be taken from a URL
 348          * @return Title|null The new object, or null on an error
 349          */
 350         public static function newFromURL( $url ) {
 351                 $t = new Title();
 352
 353                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 354                 # but some URLs used it as a space replacement and they still come
 355                 # from some external search tools.
 356                 if ( strpos( self::legalChars(), '+' ) === false ) {
 357                         $url = strtr( $url, '+', ' ' );
 358                 }
 359
 360                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 361
 362                 try {
 363                         $t->secureAndSplit();
 364                         return $t;
 365                 } catch ( MalformedTitleException $ex ) {
 366                         return null;
 367                 }
 368         }
 369
 370         /**
 371          * @return HashBagOStuff
 372          */
 373         private static function getTitleCache() {
 374                 if ( self::$titleCache == null ) {
 375                         self::$titleCache = new HashBagOStuff( array( 'maxKeys' => self::CACHE_MAX ) );
 376                 }
 377                 return self::$titleCache;
 378         }
 379
 380         /**
 381          * Returns a list of fields that are to be selected for initializing Title
 382          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 383          * whether to include page_content_model.
 384          *
 385          * @return array
 386          */
 387         protected static function getSelectFields() {
 388                 global $wgContentHandlerUseDB;
 389
 390                 $fields = array(
 391                         'page_namespace', 'page_title', 'page_id',
 392                         'page_len', 'page_is_redirect', 'page_latest',
 393                 );
 394
 395                 if ( $wgContentHandlerUseDB ) {
 396                         $fields[] = 'page_content_model';
 397                 }
 398
 399                 return $fields;
 400         }
 401
 402         /**
 403          * Create a new Title from an article ID
 404          *
 405          * @param int $id The page_id corresponding to the Title to create
 406          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 407          * @return Title|null The new object, or null on an error
 408          */
 409         public static function newFromID( $id, $flags = 0 ) {
 410                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 411                 $row = $db->selectRow(
 412                         'page',
 413                         self::getSelectFields(),
 414                         array( 'page_id' => $id ),
 415                         __METHOD__
 416                 );
 417                 if ( $row !== false ) {
 418                         $title = Title::newFromRow( $row );
 419                 } else {
 420                         $title = null;
 421                 }
 422                 return $title;
 423         }
 424
 425         /**
 426          * Make an array of titles from an array of IDs
 427          *
 428          * @param int[] $ids Array of IDs
 429          * @return Title[] Array of Titles
 430          */
 431         public static function newFromIDs( $ids ) {
 432                 if ( !count( $ids ) ) {
 433                         return array();
 434                 }
 435                 $dbr = wfGetDB( DB_SLAVE );
 436
 437                 $res = $dbr->select(
 438                         'page',
 439                         self::getSelectFields(),
 440                         array( 'page_id' => $ids ),
 441                         __METHOD__
 442                 );
 443
 444                 $titles = array();
 445                 foreach ( $res as $row ) {
 446                         $titles[] = Title::newFromRow( $row );
 447                 }
 448                 return $titles;
 449         }
 450
 451         /**
 452          * Make a Title object from a DB row
 453          *
 454          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 455          * @return Title Corresponding Title
 456          */
 457         public static function newFromRow( $row ) {
 458                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 459                 $t->loadFromRow( $row );
 460                 return $t;
 461         }
 462
 463         /**
 464          * Load Title object fields from a DB row.
 465          * If false is given, the title will be treated as non-existing.
 466          *
 467          * @param stdClass|bool $row Database row
 468          */
 469         public function loadFromRow( $row ) {
 470                 if ( $row ) { // page found
 471                         if ( isset( $row->page_id ) ) {
 472                                 $this->mArticleID = (int)$row->page_id;
 473                         }
 474                         if ( isset( $row->page_len ) ) {
 475                                 $this->mLength = (int)$row->page_len;
 476                         }
 477                         if ( isset( $row->page_is_redirect ) ) {
 478                                 $this->mRedirect = (bool)$row->page_is_redirect;
 479                         }
 480                         if ( isset( $row->page_latest ) ) {
 481                                 $this->mLatestID = (int)$row->page_latest;
 482                         }
 483                         if ( isset( $row->page_content_model ) ) {
 484                                 $this->mContentModel = strval( $row->page_content_model );
 485                         } else {
 486                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 487                         }
 488                         if ( isset( $row->page_lang ) ) {
 489                                 $this->mDbPageLanguage = (string)$row->page_lang;
 490                         }
 491                         if ( isset( $row->page_restrictions ) ) {
 492                                 $this->mOldRestrictions = $row->page_restrictions;
 493                         }
 494                 } else { // page not found
 495                         $this->mArticleID = 0;
 496                         $this->mLength = 0;
 497                         $this->mRedirect = false;
 498                         $this->mLatestID = 0;
 499                         $this->mContentModel = false; # initialized lazily in getContentModel()
 500                 }
 501         }
 502
 503         /**
 504          * Create a new Title from a namespace index and a DB key.
 505          * It's assumed that $ns and $title are *valid*, for instance when
 506          * they came directly from the database or a special page name.
 507          * For convenience, spaces are converted to underscores so that
 508          * eg user_text fields can be used directly.
 509          *
 510          * @param int $ns The namespace of the article
 511          * @param string $title The unprefixed database key form
 512          * @param string $fragment The link fragment (after the "#")
 513          * @param string $interwiki The interwiki prefix
 514          * @return Title The new object
 515          */
 516         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 517                 $t = new Title();
 518                 $t->mInterwiki = $interwiki;
 519                 $t->mFragment = $fragment;
 520                 $t->mNamespace = $ns = intval( $ns );
 521                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 522                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 523                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 524                 $t->mTextform = strtr( $title, '_', ' ' );
 525                 $t->mContentModel = false; # initialized lazily in getContentModel()
 526                 return $t;
 527         }
 528
 529         /**
 530          * Create a new Title from a namespace index and a DB key.
 531          * The parameters will be checked for validity, which is a bit slower
 532          * than makeTitle() but safer for user-provided data.
 533          *
 534          * @param int $ns The namespace of the article
 535          * @param string $title Database key form
 536          * @param string $fragment The link fragment (after the "#")
 537          * @param string $interwiki Interwiki prefix
 538          * @return Title|null The new object, or null on an error
 539          */
 540         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 541                 if ( !MWNamespace::exists( $ns ) ) {
 542                         return null;
 543                 }
 544
 545                 $t = new Title();
 546                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 547
 548                 try {
 549                         $t->secureAndSplit();
 550                         return $t;
 551                 } catch ( MalformedTitleException $ex ) {
 552                         return null;
 553                 }
 554         }
 555
 556         /**
 557          * Create a new Title for the Main Page
 558          *
 559          * @return Title The new object
 560          */
 561         public static function newMainPage() {
 562                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 563                 // Don't give fatal errors if the message is broken
 564                 if ( !$title ) {
 565                         $title = Title::newFromText( 'Main Page' );
 566                 }
 567                 return $title;
 568         }
 569
 570         /**
 571          * Extract a redirect destination from a string and return the
 572          * Title, or null if the text doesn't contain a valid redirect
 573          * This will only return the very next target, useful for
 574          * the redirect table and other checks that don't need full recursion
 575          *
 576          * @param string $text Text with possible redirect
 577          * @return Title The corresponding Title
 578          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 579          */
 580         public static function newFromRedirect( $text ) {
 581                 ContentHandler::deprecated( __METHOD__, '1.21' );
 582
 583                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 584                 return $content->getRedirectTarget();
 585         }
 586
 587         /**
 588          * Extract a redirect destination from a string and return the
 589          * Title, or null if the text doesn't contain a valid redirect
 590          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 591          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 592          *
 593          * @param string $text Text with possible redirect
 594          * @return Title
 595          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 596          */
 597         public static function newFromRedirectRecurse( $text ) {
 598                 ContentHandler::deprecated( __METHOD__, '1.21' );
 599
 600                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 601                 return $content->getUltimateRedirectTarget();
 602         }
 603
 604         /**
 605          * Extract a redirect destination from a string and return an
 606          * array of Titles, or null if the text doesn't contain a valid redirect
 607          * The last element in the array is the final destination after all redirects
 608          * have been resolved (up to $wgMaxRedirects times)
 609          *
 610          * @param string $text Text with possible redirect
 611          * @return Title[] Array of Titles, with the destination last
 612          * @deprecated since 1.21, use Content::getRedirectChain instead.
 613          */
 614         public static function newFromRedirectArray( $text ) {
 615                 ContentHandler::deprecated( __METHOD__, '1.21' );
 616
 617                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 618                 return $content->getRedirectChain();
 619         }
 620
 621         /**
 622          * Get the prefixed DB key associated with an ID
 623          *
 624          * @param int $id The page_id of the article
 625          * @return Title|null An object representing the article, or null if no such article was found
 626          */
 627         public static function nameOf( $id ) {
 628                 $dbr = wfGetDB( DB_SLAVE );
 629
 630                 $s = $dbr->selectRow(
 631                         'page',
 632                         array( 'page_namespace', 'page_title' ),
 633                         array( 'page_id' => $id ),
 634                         __METHOD__
 635                 );
 636                 if ( $s === false ) {
 637                         return null;
 638                 }
 639
 640                 $n = self::makeName( $s->page_namespace, $s->page_title );
 641                 return $n;
 642         }
 643
 644         /**
 645          * Get a regex character class describing the legal characters in a link
 646          *
 647          * @return string The list of characters, not delimited
 648          */
 649         public static function legalChars() {
 650                 global $wgLegalTitleChars;
 651                 return $wgLegalTitleChars;
 652         }
 653
 654         /**
 655          * Returns a simple regex that will match on characters and sequences invalid in titles.
 656          * Note that this doesn't pick up many things that could be wrong with titles, but that
 657          * replacing this regex with something valid will make many titles valid.
 658          *
 659          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 660          *
 661          * @return string Regex string
 662          */
 663         static function getTitleInvalidRegex() {
 664                 wfDeprecated( __METHOD__, '1.25' );
 665                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 666         }
 667
 668         /**
 669          * Utility method for converting a character sequence from bytes to Unicode.
 670          *
 671          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 672          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 673          *
 674          * @param string $byteClass
 675          * @return string
 676          */
 677         public static function convertByteClassToUnicodeClass( $byteClass ) {
 678                 $length = strlen( $byteClass );
 679                 // Input token queue
 680                 $x0 = $x1 = $x2 = '';
 681                 // Decoded queue
 682                 $d0 = $d1 = $d2 = '';
 683                 // Decoded integer codepoints
 684                 $ord0 = $ord1 = $ord2 = 0;
 685                 // Re-encoded queue
 686                 $r0 = $r1 = $r2 = '';
 687                 // Output
 688                 $out = '';
 689                 // Flags
 690                 $allowUnicode = false;
 691                 for ( $pos = 0; $pos < $length; $pos++ ) {
 692                         // Shift the queues down
 693                         $x2 = $x1;
 694                         $x1 = $x0;
 695                         $d2 = $d1;
 696                         $d1 = $d0;
 697                         $ord2 = $ord1;
 698                         $ord1 = $ord0;
 699                         $r2 = $r1;
 700                         $r1 = $r0;
 701                         // Load the current input token and decoded values
 702                         $inChar = $byteClass[$pos];
 703                         if ( $inChar == '\\' ) {
 704                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 705                                         $x0 = $inChar . $m[0];
 706                                         $d0 = chr( hexdec( $m[1] ) );
 707                                         $pos += strlen( $m[0] );
 708                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 709                                         $x0 = $inChar . $m[0];
 710                                         $d0 = chr( octdec( $m[0] ) );
 711                                         $pos += strlen( $m[0] );
 712                                 } elseif ( $pos + 1 >= $length ) {
 713                                         $x0 = $d0 = '\\';
 714                                 } else {
 715                                         $d0 = $byteClass[$pos + 1];
 716                                         $x0 = $inChar . $d0;
 717                                         $pos += 1;
 718                                 }
 719                         } else {
 720                                 $x0 = $d0 = $inChar;
 721                         }
 722                         $ord0 = ord( $d0 );
 723                         // Load the current re-encoded value
 724                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 725                                 $r0 = sprintf( '\x%02x', $ord0 );
 726                         } elseif ( $ord0 >= 0x80 ) {
 727                                 // Allow unicode if a single high-bit character appears
 728                                 $r0 = sprintf( '\x%02x', $ord0 );
 729                                 $allowUnicode = true;
 730                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 731                                 $r0 = '\\' . $d0;
 732                         } else {
 733                                 $r0 = $d0;
 734                         }
 735                         // Do the output
 736                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 737                                 // Range
 738                                 if ( $ord2 > $ord0 ) {
 739                                         // Empty range
 740                                 } elseif ( $ord0 >= 0x80 ) {
 741                                         // Unicode range
 742                                         $allowUnicode = true;
 743                                         if ( $ord2 < 0x80 ) {
 744                                                 // Keep the non-unicode section of the range
 745                                                 $out .= "$r2-\\x7F";
 746                                         }
 747                                 } else {
 748                                         // Normal range
 749                                         $out .= "$r2-$r0";
 750                                 }
 751                                 // Reset state to the initial value
 752                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 753                         } elseif ( $ord2 < 0x80 ) {
 754                                 // ASCII character
 755                                 $out .= $r2;
 756                         }
 757                 }
 758                 if ( $ord1 < 0x80 ) {
 759                         $out .= $r1;
 760                 }
 761                 if ( $ord0 < 0x80 ) {
 762                         $out .= $r0;
 763                 }
 764                 if ( $allowUnicode ) {
 765                         $out .= '\u0080-\uFFFF';
 766                 }
 767                 return $out;
 768         }
 769
 770         /**
 771          * Make a prefixed DB key from a DB key and a namespace index
 772          *
 773          * @param int $ns Numerical representation of the namespace
 774          * @param string $title The DB key form the title
 775          * @param string $fragment The link fragment (after the "#")
 776          * @param string $interwiki The interwiki prefix
 777          * @param bool $canonicalNamespace If true, use the canonical name for
 778          *   $ns instead of the localized version.
 779          * @return string The prefixed form of the title
 780          */
 781         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 782                 $canonicalNamespace = false
 783         ) {
 784                 global $wgContLang;
 785
 786                 if ( $canonicalNamespace ) {
 787                         $namespace = MWNamespace::getCanonicalName( $ns );
 788                 } else {
 789                         $namespace = $wgContLang->getNsText( $ns );
 790                 }
 791                 $name = $namespace == '' ? $title : "$namespace:$title";
 792                 if ( strval( $interwiki ) != '' ) {
 793                         $name = "$interwiki:$name";
 794                 }
 795                 if ( strval( $fragment ) != '' ) {
 796                         $name .= '#' . $fragment;
 797                 }
 798                 return $name;
 799         }
 800
 801         /**
 802          * Escape a text fragment, say from a link, for a URL
 803          *
 804          * @param string $fragment Containing a URL or link fragment (after the "#")
 805          * @return string Escaped string
 806          */
 807         static function escapeFragmentForURL( $fragment ) {
 808                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 809                 # fragments appear not to work in IE (at least up to 7) or in at least
 810                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 811                 # to care if they aren't encoded.
 812                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 813         }
 814
 815         /**
 816          * Callback for usort() to do title sorts by (namespace, title)
 817          *
 818          * @param Title $a
 819          * @param Title $b
 820          *
 821          * @return int Result of string comparison, or namespace comparison
 822          */
 823         public static function compare( $a, $b ) {
 824                 if ( $a->getNamespace() == $b->getNamespace() ) {
 825                         return strcmp( $a->getText(), $b->getText() );
 826                 } else {
 827                         return $a->getNamespace() - $b->getNamespace();
 828                 }
 829         }
 830
 831         /**
 832          * Determine whether the object refers to a page within
 833          * this project (either this wiki or a wiki with a local
 834          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 835          *
 836          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 837          */
 838         public function isLocal() {
 839                 if ( $this->isExternal() ) {
 840                         $iw = Interwiki::fetch( $this->mInterwiki );
 841                         if ( $iw ) {
 842                                 return $iw->isLocal();
 843                         }
 844                 }
 845                 return true;
 846         }
 847
 848         /**
 849          * Is this Title interwiki?
 850          *
 851          * @return bool
 852          */
 853         public function isExternal() {
 854                 return $this->mInterwiki !== '';
 855         }
 856
 857         /**
 858          * Get the interwiki prefix
 859          *
 860          * Use Title::isExternal to check if a interwiki is set
 861          *
 862          * @return string Interwiki prefix
 863          */
 864         public function getInterwiki() {
 865                 return $this->mInterwiki;
 866         }
 867
 868         /**
 869          * Was this a local interwiki link?
 870          *
 871          * @return bool
 872          */
 873         public function wasLocalInterwiki() {
 874                 return $this->mLocalInterwiki;
 875         }
 876
 877         /**
 878          * Determine whether the object refers to a page within
 879          * this project and is transcludable.
 880          *
 881          * @return bool True if this is transcludable
 882          */
 883         public function isTrans() {
 884                 if ( !$this->isExternal() ) {
 885                         return false;
 886                 }
 887
 888                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 889         }
 890
 891         /**
 892          * Returns the DB name of the distant wiki which owns the object.
 893          *
 894          * @return string The DB name
 895          */
 896         public function getTransWikiID() {
 897                 if ( !$this->isExternal() ) {
 898                         return false;
 899                 }
 900
 901                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 902         }
 903
 904         /**
 905          * Get a TitleValue object representing this Title.
 906          *
 907          * @note Not all valid Titles have a corresponding valid TitleValue
 908          * (e.g. TitleValues cannot represent page-local links that have a
 909          * fragment but no title text).
 910          *
 911          * @return TitleValue|null
 912          */
 913         public function getTitleValue() {
 914                 if ( $this->mTitleValue === null ) {
 915                         try {
 916                                 $this->mTitleValue = new TitleValue(
 917                                         $this->getNamespace(),
 918                                         $this->getDBkey(),
 919                                         $this->getFragment() );
 920                         } catch ( InvalidArgumentException $ex ) {
 921                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 922                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 923                         }
 924                 }
 925
 926                 return $this->mTitleValue;
 927         }
 928
 929         /**
 930          * Get the text form (spaces not underscores) of the main part
 931          *
 932          * @return string Main part of the title
 933          */
 934         public function getText() {
 935                 return $this->mTextform;
 936         }
 937
 938         /**
 939          * Get the URL-encoded form of the main part
 940          *
 941          * @return string Main part of the title, URL-encoded
 942          */
 943         public function getPartialURL() {
 944                 return $this->mUrlform;
 945         }
 946
 947         /**
 948          * Get the main part with underscores
 949          *
 950          * @return string Main part of the title, with underscores
 951          */
 952         public function getDBkey() {
 953                 return $this->mDbkeyform;
 954         }
 955
 956         /**
 957          * Get the DB key with the initial letter case as specified by the user
 958          *
 959          * @return string DB key
 960          */
 961         function getUserCaseDBKey() {
 962                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 963                         return $this->mUserCaseDBKey;
 964                 } else {
 965                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 966                         return $this->mDbkeyform;
 967                 }
 968         }
 969
 970         /**
 971          * Get the namespace index, i.e. one of the NS_xxxx constants.
 972          *
 973          * @return int Namespace index
 974          */
 975         public function getNamespace() {
 976                 return $this->mNamespace;
 977         }
 978
 979         /**
 980          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 981          *
 982          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 983          * @return string Content model id
 984          */
 985         public function getContentModel( $flags = 0 ) {
 986                 if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 987                         $linkCache = LinkCache::singleton();
 988                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 989                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 990                 }
 991
 992                 if ( !$this->mContentModel ) {
 993                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 994                 }
 995
 996                 return $this->mContentModel;
 997         }
 998
 999         /**
1000          * Convenience method for checking a title's content model name
1001          *
1002          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
1003          * @return bool True if $this->getContentModel() == $id
1004          */
1005         public function hasContentModel( $id ) {
1006                 return $this->getContentModel() == $id;
1007         }
1008
1009         /**
1010          * Get the namespace text
1011          *
1012          * @return string Namespace text
1013          */
1014         public function getNsText() {
1015                 if ( $this->isExternal() ) {
1016                         // This probably shouldn't even happen,
1017                         // but for interwiki transclusion it sometimes does.
1018                         // Use the canonical namespaces if possible to try to
1019                         // resolve a foreign namespace.
1020                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1021                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1022                         }
1023                 }
1024
1025                 try {
1026                         $formatter = self::getTitleFormatter();
1027                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1028                 } catch ( InvalidArgumentException $ex ) {
1029                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1030                         return false;
1031                 }
1032         }
1033
1034         /**
1035          * Get the namespace text of the subject (rather than talk) page
1036          *
1037          * @return string Namespace text
1038          */
1039         public function getSubjectNsText() {
1040                 global $wgContLang;
1041                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1042         }
1043
1044         /**
1045          * Get the namespace text of the talk page
1046          *
1047          * @return string Namespace text
1048          */
1049         public function getTalkNsText() {
1050                 global $wgContLang;
1051                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1052         }
1053
1054         /**
1055          * Could this title have a corresponding talk page?
1056          *
1057          * @return bool
1058          */
1059         public function canTalk() {
1060                 return MWNamespace::canTalk( $this->mNamespace );
1061         }
1062
1063         /**
1064          * Is this in a namespace that allows actual pages?
1065          *
1066          * @return bool
1067          */
1068         public function canExist() {
1069                 return $this->mNamespace >= NS_MAIN;
1070         }
1071
1072         /**
1073          * Can this title be added to a user's watchlist?
1074          *
1075          * @return bool
1076          */
1077         public function isWatchable() {
1078                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1079         }
1080
1081         /**
1082          * Returns true if this is a special page.
1083          *
1084          * @return bool
1085          */
1086         public function isSpecialPage() {
1087                 return $this->getNamespace() == NS_SPECIAL;
1088         }
1089
1090         /**
1091          * Returns true if this title resolves to the named special page
1092          *
1093          * @param string $name The special page name
1094          * @return bool
1095          */
1096         public function isSpecial( $name ) {
1097                 if ( $this->isSpecialPage() ) {
1098                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1099                         if ( $name == $thisName ) {
1100                                 return true;
1101                         }
1102                 }
1103                 return false;
1104         }
1105
1106         /**
1107          * If the Title refers to a special page alias which is not the local default, resolve
1108          * the alias, and localise the name as necessary.  Otherwise, return $this
1109          *
1110          * @return Title
1111          */
1112         public function fixSpecialName() {
1113                 if ( $this->isSpecialPage() ) {
1114                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1115                         if ( $canonicalName ) {
1116                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1117                                 if ( $localName != $this->mDbkeyform ) {
1118                                         return Title::makeTitle( NS_SPECIAL, $localName );
1119                                 }
1120                         }
1121                 }
1122                 return $this;
1123         }
1124
1125         /**
1126          * Returns true if the title is inside the specified namespace.
1127          *
1128          * Please make use of this instead of comparing to getNamespace()
1129          * This function is much more resistant to changes we may make
1130          * to namespaces than code that makes direct comparisons.
1131          * @param int $ns The namespace
1132          * @return bool
1133          * @since 1.19
1134          */
1135         public function inNamespace( $ns ) {
1136                 return MWNamespace::equals( $this->getNamespace(), $ns );
1137         }
1138
1139         /**
1140          * Returns true if the title is inside one of the specified namespaces.
1141          *
1142          * @param int $namespaces,... The namespaces to check for
1143          * @return bool
1144          * @since 1.19
1145          */
1146         public function inNamespaces( /* ... */ ) {
1147                 $namespaces = func_get_args();
1148                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1149                         $namespaces = $namespaces[0];
1150                 }
1151
1152                 foreach ( $namespaces as $ns ) {
1153                         if ( $this->inNamespace( $ns ) ) {
1154                                 return true;
1155                         }
1156                 }
1157
1158                 return false;
1159         }
1160
1161         /**
1162          * Returns true if the title has the same subject namespace as the
1163          * namespace specified.
1164          * For example this method will take NS_USER and return true if namespace
1165          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1166          * as their subject namespace.
1167          *
1168          * This is MUCH simpler than individually testing for equivalence
1169          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1170          * @since 1.19
1171          * @param int $ns
1172          * @return bool
1173          */
1174         public function hasSubjectNamespace( $ns ) {
1175                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1176         }
1177
1178         /**
1179          * Is this Title in a namespace which contains content?
1180          * In other words, is this a content page, for the purposes of calculating
1181          * statistics, etc?
1182          *
1183          * @return bool
1184          */
1185         public function isContentPage() {
1186                 return MWNamespace::isContent( $this->getNamespace() );
1187         }
1188
1189         /**
1190          * Would anybody with sufficient privileges be able to move this page?
1191          * Some pages just aren't movable.
1192          *
1193          * @return bool
1194          */
1195         public function isMovable() {
1196                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1197                         // Interwiki title or immovable namespace. Hooks don't get to override here
1198                         return false;
1199                 }
1200
1201                 $result = true;
1202                 Hooks::run( 'TitleIsMovable', array( $this, &$result ) );
1203                 return $result;
1204         }
1205
1206         /**
1207          * Is this the mainpage?
1208          * @note Title::newFromText seems to be sufficiently optimized by the title
1209          * cache that we don't need to over-optimize by doing direct comparisons and
1210          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1211          * ends up reporting something differently than $title->isMainPage();
1212          *
1213          * @since 1.18
1214          * @return bool
1215          */
1216         public function isMainPage() {
1217                 return $this->equals( Title::newMainPage() );
1218         }
1219
1220         /**
1221          * Is this a subpage?
1222          *
1223          * @return bool
1224          */
1225         public function isSubpage() {
1226                 return MWNamespace::hasSubpages( $this->mNamespace )
1227                         ? strpos( $this->getText(), '/' ) !== false
1228                         : false;
1229         }
1230
1231         /**
1232          * Is this a conversion table for the LanguageConverter?
1233          *
1234          * @return bool
1235          */
1236         public function isConversionTable() {
1237                 // @todo ConversionTable should become a separate content model.
1238
1239                 return $this->getNamespace() == NS_MEDIAWIKI &&
1240                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1241         }
1242
1243         /**
1244          * Does that page contain wikitext, or it is JS, CSS or whatever?
1245          *
1246          * @return bool
1247          */
1248         public function isWikitextPage() {
1249                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1250         }
1251
1252         /**
1253          * Could this page contain custom CSS or JavaScript for the global UI.
1254          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1255          * or CONTENT_MODEL_JAVASCRIPT.
1256          *
1257          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1258          * for that!
1259          *
1260          * Note that this method should not return true for pages that contain and
1261          * show "inactive" CSS or JS.
1262          *
1263          * @return bool
1264          */
1265         public function isCssOrJsPage() {
1266                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1267                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1268                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1269
1270                 # @note This hook is also called in ContentHandler::getDefaultModel.
1271                 #   It's called here again to make sure hook functions can force this
1272                 #   method to return true even outside the MediaWiki namespace.
1273
1274                 Hooks::run( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ), '1.25' );
1275
1276                 return $isCssOrJsPage;
1277         }
1278
1279         /**
1280          * Is this a .css or .js subpage of a user page?
1281          * @return bool
1282          */
1283         public function isCssJsSubpage() {
1284                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1285                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1286                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1287         }
1288
1289         /**
1290          * Trim down a .css or .js subpage title to get the corresponding skin name
1291          *
1292          * @return string Containing skin name from .css or .js subpage title
1293          */
1294         public function getSkinFromCssJsSubpage() {
1295                 $subpage = explode( '/', $this->mTextform );
1296                 $subpage = $subpage[count( $subpage ) - 1];
1297                 $lastdot = strrpos( $subpage, '.' );
1298                 if ( $lastdot === false ) {
1299                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1300                 }
1301                 return substr( $subpage, 0, $lastdot );
1302         }
1303
1304         /**
1305          * Is this a .css subpage of a user page?
1306          *
1307          * @return bool
1308          */
1309         public function isCssSubpage() {
1310                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1311                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1312         }
1313
1314         /**
1315          * Is this a .js subpage of a user page?
1316          *
1317          * @return bool
1318          */
1319         public function isJsSubpage() {
1320                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1321                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1322         }
1323
1324         /**
1325          * Is this a talk page of some sort?
1326          *
1327          * @return bool
1328          */
1329         public function isTalkPage() {
1330                 return MWNamespace::isTalk( $this->getNamespace() );
1331         }
1332
1333         /**
1334          * Get a Title object associated with the talk page of this article
1335          *
1336          * @return Title The object for the talk page
1337          */
1338         public function getTalkPage() {
1339                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1340         }
1341
1342         /**
1343          * Get a title object associated with the subject page of this
1344          * talk page
1345          *
1346          * @return Title The object for the subject page
1347          */
1348         public function getSubjectPage() {
1349                 // Is this the same title?
1350                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1351                 if ( $this->getNamespace() == $subjectNS ) {
1352                         return $this;
1353                 }
1354                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1355         }
1356
1357         /**
1358          * Get the other title for this page, if this is a subject page
1359          * get the talk page, if it is a subject page get the talk page
1360          *
1361          * @since 1.25
1362          * @throws MWException
1363          * @return Title
1364          */
1365         public function getOtherPage() {
1366                 if ( $this->isSpecialPage() ) {
1367                         throw new MWException( 'Special pages cannot have other pages' );
1368                 }
1369                 if ( $this->isTalkPage() ) {
1370                         return $this->getSubjectPage();
1371                 } else {
1372                         return $this->getTalkPage();
1373                 }
1374         }
1375
1376         /**
1377          * Get the default namespace index, for when there is no namespace
1378          *
1379          * @return int Default namespace index
1380          */
1381         public function getDefaultNamespace() {
1382                 return $this->mDefaultNamespace;
1383         }
1384
1385         /**
1386          * Get the Title fragment (i.e.\ the bit after the #) in text form
1387          *
1388          * Use Title::hasFragment to check for a fragment
1389          *
1390          * @return string Title fragment
1391          */
1392         public function getFragment() {
1393                 return $this->mFragment;
1394         }
1395
1396         /**
1397          * Check if a Title fragment is set
1398          *
1399          * @return bool
1400          * @since 1.23
1401          */
1402         public function hasFragment() {
1403                 return $this->mFragment !== '';
1404         }
1405
1406         /**
1407          * Get the fragment in URL form, including the "#" character if there is one
1408          * @return string Fragment in URL form
1409          */
1410         public function getFragmentForURL() {
1411                 if ( !$this->hasFragment() ) {
1412                         return '';
1413                 } else {
1414                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1415                 }
1416         }
1417
1418         /**
1419          * Set the fragment for this title. Removes the first character from the
1420          * specified fragment before setting, so it assumes you're passing it with
1421          * an initial "#".
1422          *
1423          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1424          * Still in active use privately.
1425          *
1426          * @private
1427          * @param string $fragment Text
1428          */
1429         public function setFragment( $fragment ) {
1430                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1431         }
1432
1433         /**
1434          * Prefix some arbitrary text with the namespace or interwiki prefix
1435          * of this object
1436          *
1437          * @param string $name The text
1438          * @return string The prefixed text
1439          */
1440         private function prefix( $name ) {
1441                 $p = '';
1442                 if ( $this->isExternal() ) {
1443                         $p = $this->mInterwiki . ':';
1444                 }
1445
1446                 if ( 0 != $this->mNamespace ) {
1447                         $p .= $this->getNsText() . ':';
1448                 }
1449                 return $p . $name;
1450         }
1451
1452         /**
1453          * Get the prefixed database key form
1454          *
1455          * @return string The prefixed title, with underscores and
1456          *  any interwiki and namespace prefixes
1457          */
1458         public function getPrefixedDBkey() {
1459                 $s = $this->prefix( $this->mDbkeyform );
1460                 $s = strtr( $s, ' ', '_' );
1461                 return $s;
1462         }
1463
1464         /**
1465          * Get the prefixed title with spaces.
1466          * This is the form usually used for display
1467          *
1468          * @return string The prefixed title, with spaces
1469          */
1470         public function getPrefixedText() {
1471                 if ( $this->mPrefixedText === null ) {
1472                         $s = $this->prefix( $this->mTextform );
1473                         $s = strtr( $s, '_', ' ' );
1474                         $this->mPrefixedText = $s;
1475                 }
1476                 return $this->mPrefixedText;
1477         }
1478
1479         /**
1480          * Return a string representation of this title
1481          *
1482          * @return string Representation of this title
1483          */
1484         public function __toString() {
1485                 return $this->getPrefixedText();
1486         }
1487
1488         /**
1489          * Get the prefixed title with spaces, plus any fragment
1490          * (part beginning with '#')
1491          *
1492          * @return string The prefixed title, with spaces and the fragment, including '#'
1493          */
1494         public function getFullText() {
1495                 $text = $this->getPrefixedText();
1496                 if ( $this->hasFragment() ) {
1497                         $text .= '#' . $this->getFragment();
1498                 }
1499                 return $text;
1500         }
1501
1502         /**
1503          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1504          *
1505          * @par Example:
1506          * @code
1507          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1508          * # returns: 'Foo'
1509          * @endcode
1510          *
1511          * @return string Root name
1512          * @since 1.20
1513          */
1514         public function getRootText() {
1515                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1516                         return $this->getText();
1517                 }
1518
1519                 return strtok( $this->getText(), '/' );
1520         }
1521
1522         /**
1523          * Get the root page name title, i.e. the leftmost part before any slashes
1524          *
1525          * @par Example:
1526          * @code
1527          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1528          * # returns: Title{User:Foo}
1529          * @endcode
1530          *
1531          * @return Title Root title
1532          * @since 1.20
1533          */
1534         public function getRootTitle() {
1535                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1536         }
1537
1538         /**
1539          * Get the base page name without a namespace, i.e. the part before the subpage name
1540          *
1541          * @par Example:
1542          * @code
1543          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1544          * # returns: 'Foo/Bar'
1545          * @endcode
1546          *
1547          * @return string Base name
1548          */
1549         public function getBaseText() {
1550                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1551                         return $this->getText();
1552                 }
1553
1554                 $parts = explode( '/', $this->getText() );
1555                 # Don't discard the real title if there's no subpage involved
1556                 if ( count( $parts ) > 1 ) {
1557                         unset( $parts[count( $parts ) - 1] );
1558                 }
1559                 return implode( '/', $parts );
1560         }
1561
1562         /**
1563          * Get the base page name title, i.e. the part before the subpage name
1564          *
1565          * @par Example:
1566          * @code
1567          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1568          * # returns: Title{User:Foo/Bar}
1569          * @endcode
1570          *
1571          * @return Title Base title
1572          * @since 1.20
1573          */
1574         public function getBaseTitle() {
1575                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1576         }
1577
1578         /**
1579          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1580          *
1581          * @par Example:
1582          * @code
1583          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1584          * # returns: "Baz"
1585          * @endcode
1586          *
1587          * @return string Subpage name
1588          */
1589         public function getSubpageText() {
1590                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1591                         return $this->mTextform;
1592                 }
1593                 $parts = explode( '/', $this->mTextform );
1594                 return $parts[count( $parts ) - 1];
1595         }
1596
1597         /**
1598          * Get the title for a subpage of the current page
1599          *
1600          * @par Example:
1601          * @code
1602          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1603          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1604          * @endcode
1605          *
1606          * @param string $text The subpage name to add to the title
1607          * @return Title Subpage title
1608          * @since 1.20
1609          */
1610         public function getSubpage( $text ) {
1611                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1612         }
1613
1614         /**
1615          * Get a URL-encoded form of the subpage text
1616          *
1617          * @return string URL-encoded subpage name
1618          */
1619         public function getSubpageUrlForm() {
1620                 $text = $this->getSubpageText();
1621                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1622                 return $text;
1623         }
1624
1625         /**
1626          * Get a URL-encoded title (not an actual URL) including interwiki
1627          *
1628          * @return string The URL-encoded form
1629          */
1630         public function getPrefixedURL() {
1631                 $s = $this->prefix( $this->mDbkeyform );
1632                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1633                 return $s;
1634         }
1635
1636         /**
1637          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1638          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1639          * second argument named variant. This was deprecated in favor
1640          * of passing an array of option with a "variant" key
1641          * Once $query2 is removed for good, this helper can be dropped
1642          * and the wfArrayToCgi moved to getLocalURL();
1643          *
1644          * @since 1.19 (r105919)
1645          * @param array|string $query
1646          * @param bool $query2
1647          * @return string
1648          */
1649         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1650                 if ( $query2 !== false ) {
1651                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1652                                 "method called with a second parameter is deprecated. Add your " .
1653                                 "parameter to an array passed as the first parameter.", "1.19" );
1654                 }
1655                 if ( is_array( $query ) ) {
1656                         $query = wfArrayToCgi( $query );
1657                 }
1658                 if ( $query2 ) {
1659                         if ( is_string( $query2 ) ) {
1660                                 // $query2 is a string, we will consider this to be
1661                                 // a deprecated $variant argument and add it to the query
1662                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1663                         } else {
1664                                 $query2 = wfArrayToCgi( $query2 );
1665                         }
1666                         // If we have $query content add a & to it first
1667                         if ( $query ) {
1668                                 $query .= '&';
1669                         }
1670                         // Now append the queries together
1671                         $query .= $query2;
1672                 }
1673                 return $query;
1674         }
1675
1676         /**
1677          * Get a real URL referring to this title, with interwiki link and
1678          * fragment
1679          *
1680          * @see self::getLocalURL for the arguments.
1681          * @see wfExpandUrl
1682          * @param array|string $query
1683          * @param bool $query2
1684          * @param string $proto Protocol type to use in URL
1685          * @return string The URL
1686          */
1687         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1688                 $query = self::fixUrlQueryArgs( $query, $query2 );
1689
1690                 # Hand off all the decisions on urls to getLocalURL
1691                 $url = $this->getLocalURL( $query );
1692
1693                 # Expand the url to make it a full url. Note that getLocalURL has the
1694                 # potential to output full urls for a variety of reasons, so we use
1695                 # wfExpandUrl instead of simply prepending $wgServer
1696                 $url = wfExpandUrl( $url, $proto );
1697
1698                 # Finally, add the fragment.
1699                 $url .= $this->getFragmentForURL();
1700
1701                 Hooks::run( 'GetFullURL', array( &$this, &$url, $query ) );
1702                 return $url;
1703         }
1704
1705         /**
1706          * Get a URL with no fragment or server name (relative URL) from a Title object.
1707          * If this page is generated with action=render, however,
1708          * $wgServer is prepended to make an absolute URL.
1709          *
1710          * @see self::getFullURL to always get an absolute URL.
1711          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1712          *  valid to link, locally, to the current Title.
1713          * @see self::newFromText to produce a Title object.
1714          *
1715          * @param string|array $query An optional query string,
1716          *   not used for interwiki links. Can be specified as an associative array as well,
1717          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1718          *   Some query patterns will trigger various shorturl path replacements.
1719          * @param array $query2 An optional secondary query array. This one MUST
1720          *   be an array. If a string is passed it will be interpreted as a deprecated
1721          *   variant argument and urlencoded into a variant= argument.
1722          *   This second query argument will be added to the $query
1723          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1724          *   pair in the first parameter array instead.
1725          *
1726          * @return string String of the URL.
1727          */
1728         public function getLocalURL( $query = '', $query2 = false ) {
1729                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1730
1731                 $query = self::fixUrlQueryArgs( $query, $query2 );
1732
1733                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1734                 if ( $interwiki ) {
1735                         $namespace = $this->getNsText();
1736                         if ( $namespace != '' ) {
1737                                 # Can this actually happen? Interwikis shouldn't be parsed.
1738                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1739                                 $namespace .= ':';
1740                         }
1741                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1742                         $url = wfAppendQuery( $url, $query );
1743                 } else {
1744                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1745                         if ( $query == '' ) {
1746                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1747                                 Hooks::run( 'GetLocalURL::Article', array( &$this, &$url ) );
1748                         } else {
1749                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1750                                 $url = false;
1751                                 $matches = array();
1752
1753                                 if ( !empty( $wgActionPaths )
1754                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1755                                 ) {
1756                                         $action = urldecode( $matches[2] );
1757                                         if ( isset( $wgActionPaths[$action] ) ) {
1758                                                 $query = $matches[1];
1759                                                 if ( isset( $matches[4] ) ) {
1760                                                         $query .= $matches[4];
1761                                                 }
1762                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1763                                                 if ( $query != '' ) {
1764                                                         $url = wfAppendQuery( $url, $query );
1765                                                 }
1766                                         }
1767                                 }
1768
1769                                 if ( $url === false
1770                                         && $wgVariantArticlePath
1771                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1772                                         && $this->getPageLanguage()->hasVariants()
1773                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1774                                 ) {
1775                                         $variant = urldecode( $matches[1] );
1776                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1777                                                 // Only do the variant replacement if the given variant is a valid
1778                                                 // variant for the page's language.
1779                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1780                                                 $url = str_replace( '$1', $dbkey, $url );
1781                                         }
1782                                 }
1783
1784                                 if ( $url === false ) {
1785                                         if ( $query == '-' ) {
1786                                                 $query = '';
1787                                         }
1788                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1789                                 }
1790                         }
1791
1792                         Hooks::run( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1793
1794                         // @todo FIXME: This causes breakage in various places when we
1795                         // actually expected a local URL and end up with dupe prefixes.
1796                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1797                                 $url = $wgServer . $url;
1798                         }
1799                 }
1800                 Hooks::run( 'GetLocalURL', array( &$this, &$url, $query ) );
1801                 return $url;
1802         }
1803
1804         /**
1805          * Get a URL that's the simplest URL that will be valid to link, locally,
1806          * to the current Title.  It includes the fragment, but does not include
1807          * the server unless action=render is used (or the link is external).  If
1808          * there's a fragment but the prefixed text is empty, we just return a link
1809          * to the fragment.
1810          *
1811          * The result obviously should not be URL-escaped, but does need to be
1812          * HTML-escaped if it's being output in HTML.
1813          *
1814          * @param array $query
1815          * @param bool $query2
1816          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1817          * @see self::getLocalURL for the arguments.
1818          * @return string The URL
1819          */
1820         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1821                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1822                         $ret = $this->getFullURL( $query, $query2, $proto );
1823                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1824                         $ret = $this->getFragmentForURL();
1825                 } else {
1826                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1827                 }
1828                 return $ret;
1829         }
1830
1831         /**
1832          * Get the URL form for an internal link.
1833          * - Used in various CDN-related code, in case we have a different
1834          * internal hostname for the server from the exposed one.
1835          *
1836          * This uses $wgInternalServer to qualify the path, or $wgServer
1837          * if $wgInternalServer is not set. If the server variable used is
1838          * protocol-relative, the URL will be expanded to http://
1839          *
1840          * @see self::getLocalURL for the arguments.
1841          * @return string The URL
1842          */
1843         public function getInternalURL( $query = '', $query2 = false ) {
1844                 global $wgInternalServer, $wgServer;
1845                 $query = self::fixUrlQueryArgs( $query, $query2 );
1846                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1847                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1848                 Hooks::run( 'GetInternalURL', array( &$this, &$url, $query ) );
1849                 return $url;
1850         }
1851
1852         /**
1853          * Get the URL for a canonical link, for use in things like IRC and
1854          * e-mail notifications. Uses $wgCanonicalServer and the
1855          * GetCanonicalURL hook.
1856          *
1857          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1858          *
1859          * @see self::getLocalURL for the arguments.
1860          * @return string The URL
1861          * @since 1.18
1862          */
1863         public function getCanonicalURL( $query = '', $query2 = false ) {
1864                 $query = self::fixUrlQueryArgs( $query, $query2 );
1865                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1866                 Hooks::run( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1867                 return $url;
1868         }
1869
1870         /**
1871          * Get the edit URL for this Title
1872          *
1873          * @return string The URL, or a null string if this is an interwiki link
1874          */
1875         public function getEditURL() {
1876                 if ( $this->isExternal() ) {
1877                         return '';
1878                 }
1879                 $s = $this->getLocalURL( 'action=edit' );
1880
1881                 return $s;
1882         }
1883
1884         /**
1885          * Can $user perform $action on this page?
1886          * This skips potentially expensive cascading permission checks
1887          * as well as avoids expensive error formatting
1888          *
1889          * Suitable for use for nonessential UI controls in common cases, but
1890          * _not_ for functional access control.
1891          *
1892          * May provide false positives, but should never provide a false negative.
1893          *
1894          * @param string $action Action that permission needs to be checked for
1895          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1896          * @return bool
1897          */
1898         public function quickUserCan( $action, $user = null ) {
1899                 return $this->userCan( $action, $user, false );
1900         }
1901
1902         /**
1903          * Can $user perform $action on this page?
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
1907          *   provided.
1908          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1909          * @return bool
1910          */
1911         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1912                 if ( !$user instanceof User ) {
1913                         global $wgUser;
1914                         $user = $wgUser;
1915                 }
1916
1917                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1918         }
1919
1920         /**
1921          * Can $user perform $action on this page?
1922          *
1923          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1924          *
1925          * @param string $action Action that permission needs to be checked for
1926          * @param User $user User to check
1927          * @param string $rigor One of (quick,full,secure)
1928          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
1929          *   - full   : does cheap and expensive checks possibly from a slave
1930          *   - secure : does cheap and expensive checks, using the master as needed
1931          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1932          *   whose corresponding errors may be ignored.
1933          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1934          */
1935         public function getUserPermissionsErrors(
1936                 $action, $user, $rigor = 'secure', $ignoreErrors = array()
1937         ) {
1938                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1939
1940                 // Remove the errors being ignored.
1941                 foreach ( $errors as $index => $error ) {
1942                         $errKey = is_array( $error ) ? $error[0] : $error;
1943
1944                         if ( in_array( $errKey, $ignoreErrors ) ) {
1945                                 unset( $errors[$index] );
1946                         }
1947                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1948                                 unset( $errors[$index] );
1949                         }
1950                 }
1951
1952                 return $errors;
1953         }
1954
1955         /**
1956          * Permissions checks that fail most often, and which are easiest to test.
1957          *
1958          * @param string $action The action to check
1959          * @param User $user User to check
1960          * @param array $errors List of current errors
1961          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1962          * @param bool $short Short circuit on first error
1963          *
1964          * @return array List of errors
1965          */
1966         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1967                 if ( !Hooks::run( 'TitleQuickPermissions',
1968                         array( $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ) )
1969                 ) {
1970                         return $errors;
1971                 }
1972
1973                 if ( $action == 'create' ) {
1974                         if (
1975                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1976                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1977                         ) {
1978                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1979                         }
1980                 } elseif ( $action == 'move' ) {
1981                         if ( !$user->isAllowed( 'move-rootuserpages' )
1982                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1983                                 // Show user page-specific message only if the user can move other pages
1984                                 $errors[] = array( 'cant-move-user-page' );
1985                         }
1986
1987                         // Check if user is allowed to move files if it's a file
1988                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1989                                 $errors[] = array( 'movenotallowedfile' );
1990                         }
1991
1992                         // Check if user is allowed to move category pages if it's a category page
1993                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
1994                                 $errors[] = array( 'cant-move-category-page' );
1995                         }
1996
1997                         if ( !$user->isAllowed( 'move' ) ) {
1998                                 // User can't move anything
1999                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2000                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2001                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2002                                         // custom message if logged-in users without any special rights can move
2003                                         $errors[] = array( 'movenologintext' );
2004                                 } else {
2005                                         $errors[] = array( 'movenotallowed' );
2006                                 }
2007                         }
2008                 } elseif ( $action == 'move-target' ) {
2009                         if ( !$user->isAllowed( 'move' ) ) {
2010                                 // User can't move anything
2011                                 $errors[] = array( 'movenotallowed' );
2012                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2013                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2014                                 // Show user page-specific message only if the user can move other pages
2015                                 $errors[] = array( 'cant-move-to-user-page' );
2016                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2017                                         && $this->mNamespace == NS_CATEGORY ) {
2018                                 // Show category page-specific message only if the user can move other pages
2019                                 $errors[] = array( 'cant-move-to-category-page' );
2020                         }
2021                 } elseif ( !$user->isAllowed( $action ) ) {
2022                         $errors[] = $this->missingPermissionError( $action, $short );
2023                 }
2024
2025                 return $errors;
2026         }
2027
2028         /**
2029          * Add the resulting error code to the errors array
2030          *
2031          * @param array $errors List of current errors
2032          * @param array $result Result of errors
2033          *
2034          * @return array List of errors
2035          */
2036         private function resultToError( $errors, $result ) {
2037                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2038                         // A single array representing an error
2039                         $errors[] = $result;
2040                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2041                         // A nested array representing multiple errors
2042                         $errors = array_merge( $errors, $result );
2043                 } elseif ( $result !== '' && is_string( $result ) ) {
2044                         // A string representing a message-id
2045                         $errors[] = array( $result );
2046                 } elseif ( $result instanceof MessageSpecifier ) {
2047                         // A message specifier representing an error
2048                         $errors[] = array( $result );
2049                 } elseif ( $result === false ) {
2050                         // a generic "We don't want them to do that"
2051                         $errors[] = array( 'badaccess-group0' );
2052                 }
2053                 return $errors;
2054         }
2055
2056         /**
2057          * Check various permission hooks
2058          *
2059          * @param string $action The action to check
2060          * @param User $user User to check
2061          * @param array $errors List of current errors
2062          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2063          * @param bool $short Short circuit on first error
2064          *
2065          * @return array List of errors
2066          */
2067         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2068                 // Use getUserPermissionsErrors instead
2069                 $result = '';
2070                 if ( !Hooks::run( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2071                         return $result ? array() : array( array( 'badaccess-group0' ) );
2072                 }
2073                 // Check getUserPermissionsErrors hook
2074                 if ( !Hooks::run( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2075                         $errors = $this->resultToError( $errors, $result );
2076                 }
2077                 // Check getUserPermissionsErrorsExpensive hook
2078                 if (
2079                         $rigor !== 'quick'
2080                         && !( $short && count( $errors ) > 0 )
2081                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2082                 ) {
2083                         $errors = $this->resultToError( $errors, $result );
2084                 }
2085
2086                 return $errors;
2087         }
2088
2089         /**
2090          * Check permissions on special pages & namespaces
2091          *
2092          * @param string $action The action to check
2093          * @param User $user User to check
2094          * @param array $errors List of current errors
2095          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2096          * @param bool $short Short circuit on first error
2097          *
2098          * @return array List of errors
2099          */
2100         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2101                 # Only 'createaccount' can be performed on special pages,
2102                 # which don't actually exist in the DB.
2103                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2104                         $errors[] = array( 'ns-specialprotected' );
2105                 }
2106
2107                 # Check $wgNamespaceProtection for restricted namespaces
2108                 if ( $this->isNamespaceProtected( $user ) ) {
2109                         $ns = $this->mNamespace == NS_MAIN ?
2110                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2111                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2112                                 array( 'protectedinterface', $action ) : array( 'namespaceprotected', $ns, $action );
2113                 }
2114
2115                 return $errors;
2116         }
2117
2118         /**
2119          * Check CSS/JS sub-page permissions
2120          *
2121          * @param string $action The action to check
2122          * @param User $user User to check
2123          * @param array $errors List of current errors
2124          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2125          * @param bool $short Short circuit on first error
2126          *
2127          * @return array List of errors
2128          */
2129         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2130                 # Protect css/js subpages of user pages
2131                 # XXX: this might be better using restrictions
2132                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2133                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2134                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2135                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2136                                         $errors[] = array( 'mycustomcssprotected', $action );
2137                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2138                                         $errors[] = array( 'mycustomjsprotected', $action );
2139                                 }
2140                         } else {
2141                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2142                                         $errors[] = array( 'customcssprotected', $action );
2143                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2144                                         $errors[] = array( 'customjsprotected', $action );
2145                                 }
2146                         }
2147                 }
2148
2149                 return $errors;
2150         }
2151
2152         /**
2153          * Check against page_restrictions table requirements on this
2154          * page. The user must possess all required rights for this
2155          * action.
2156          *
2157          * @param string $action The action to check
2158          * @param User $user User to check
2159          * @param array $errors List of current errors
2160          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2161          * @param bool $short Short circuit on first error
2162          *
2163          * @return array List of errors
2164          */
2165         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2166                 foreach ( $this->getRestrictions( $action ) as $right ) {
2167                         // Backwards compatibility, rewrite sysop -> editprotected
2168                         if ( $right == 'sysop' ) {
2169                                 $right = 'editprotected';
2170                         }
2171                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2172                         if ( $right == 'autoconfirmed' ) {
2173                                 $right = 'editsemiprotected';
2174                         }
2175                         if ( $right == '' ) {
2176                                 continue;
2177                         }
2178                         if ( !$user->isAllowed( $right ) ) {
2179                                 $errors[] = array( 'protectedpagetext', $right, $action );
2180                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2181                                 $errors[] = array( 'protectedpagetext', 'protect', $action );
2182                         }
2183                 }
2184
2185                 return $errors;
2186         }
2187
2188         /**
2189          * Check restrictions on cascading pages.
2190          *
2191          * @param string $action The action to check
2192          * @param User $user User to check
2193          * @param array $errors List of current errors
2194          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2195          * @param bool $short Short circuit on first error
2196          *
2197          * @return array List of errors
2198          */
2199         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2200                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2201                         # We /could/ use the protection level on the source page, but it's
2202                         # fairly ugly as we have to establish a precedence hierarchy for pages
2203                         # included by multiple cascade-protected pages. So just restrict
2204                         # it to people with 'protect' permission, as they could remove the
2205                         # protection anyway.
2206                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2207                         # Cascading protection depends on more than this page...
2208                         # Several cascading protected pages may include this page...
2209                         # Check each cascading level
2210                         # This is only for protection restrictions, not for all actions
2211                         if ( isset( $restrictions[$action] ) ) {
2212                                 foreach ( $restrictions[$action] as $right ) {
2213                                         // Backwards compatibility, rewrite sysop -> editprotected
2214                                         if ( $right == 'sysop' ) {
2215                                                 $right = 'editprotected';
2216                                         }
2217                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2218                                         if ( $right == 'autoconfirmed' ) {
2219                                                 $right = 'editsemiprotected';
2220                                         }
2221                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2222                                                 $pages = '';
2223                                                 foreach ( $cascadingSources as $page ) {
2224                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2225                                                 }
2226                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages, $action );
2227                                         }
2228                                 }
2229                         }
2230                 }
2231
2232                 return $errors;
2233         }
2234
2235         /**
2236          * Check action permissions not already checked in checkQuickPermissions
2237          *
2238          * @param string $action The action to check
2239          * @param User $user User to check
2240          * @param array $errors List of current errors
2241          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2242          * @param bool $short Short circuit on first error
2243          *
2244          * @return array List of errors
2245          */
2246         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2247                 global $wgDeleteRevisionsLimit, $wgLang;
2248
2249                 if ( $action == 'protect' ) {
2250                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2251                                 // If they can't edit, they shouldn't protect.
2252                                 $errors[] = array( 'protect-cantedit' );
2253                         }
2254                 } elseif ( $action == 'create' ) {
2255                         $title_protection = $this->getTitleProtection();
2256                         if ( $title_protection ) {
2257                                 if ( $title_protection['permission'] == ''
2258                                         || !$user->isAllowed( $title_protection['permission'] )
2259                                 ) {
2260                                         $errors[] = array(
2261                                                 'titleprotected',
2262                                                 User::whoIs( $title_protection['user'] ),
2263                                                 $title_protection['reason']
2264                                         );
2265                                 }
2266                         }
2267                 } elseif ( $action == 'move' ) {
2268                         // Check for immobile pages
2269                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2270                                 // Specific message for this case
2271                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2272                         } elseif ( !$this->isMovable() ) {
2273                                 // Less specific message for rarer cases
2274                                 $errors[] = array( 'immobile-source-page' );
2275                         }
2276                 } elseif ( $action == 'move-target' ) {
2277                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2278                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2279                         } elseif ( !$this->isMovable() ) {
2280                                 $errors[] = array( 'immobile-target-page' );
2281                         }
2282                 } elseif ( $action == 'delete' ) {
2283                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, array(), $rigor, true );
2284                         if ( !$tempErrors ) {
2285                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2286                                         $user, $tempErrors, $rigor, true );
2287                         }
2288                         if ( $tempErrors ) {
2289                                 // If protection keeps them from editing, they shouldn't be able to delete.
2290                                 $errors[] = array( 'deleteprotected' );
2291                         }
2292                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2293                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2294                         ) {
2295                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2296                         }
2297                 }
2298                 return $errors;
2299         }
2300
2301         /**
2302          * Check that the user isn't blocked from editing.
2303          *
2304          * @param string $action The action to check
2305          * @param User $user User to check
2306          * @param array $errors List of current errors
2307          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2308          * @param bool $short Short circuit on first error
2309          *
2310          * @return array List of errors
2311          */
2312         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2313                 // Account creation blocks handled at userlogin.
2314                 // Unblocking handled in SpecialUnblock
2315                 if ( $rigor === 'quick' || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2316                         return $errors;
2317                 }
2318
2319                 global $wgEmailConfirmToEdit;
2320
2321                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2322                         $errors[] = array( 'confirmedittext' );
2323                 }
2324
2325                 $useSlave = ( $rigor !== 'secure' );
2326                 if ( ( $action == 'edit' || $action == 'create' )
2327                         && !$user->isBlockedFrom( $this, $useSlave )
2328                 ) {
2329                         // Don't block the user from editing their own talk page unless they've been
2330                         // explicitly blocked from that too.
2331                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2332                         // @todo FIXME: Pass the relevant context into this function.
2333                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2334                 }
2335
2336                 return $errors;
2337         }
2338
2339         /**
2340          * Check that the user is allowed to read this page.
2341          *
2342          * @param string $action The action to check
2343          * @param User $user User to check
2344          * @param array $errors List of current errors
2345          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2346          * @param bool $short Short circuit on first error
2347          *
2348          * @return array List of errors
2349          */
2350         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2351                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2352
2353                 $whitelisted = false;
2354                 if ( User::isEveryoneAllowed( 'read' ) ) {
2355                         # Shortcut for public wikis, allows skipping quite a bit of code
2356                         $whitelisted = true;
2357                 } elseif ( $user->isAllowed( 'read' ) ) {
2358                         # If the user is allowed to read pages, he is allowed to read all pages
2359                         $whitelisted = true;
2360                 } elseif ( $this->isSpecial( 'Userlogin' )
2361                         || $this->isSpecial( 'ChangePassword' )
2362                         || $this->isSpecial( 'PasswordReset' )
2363                 ) {
2364                         # Always grant access to the login page.
2365                         # Even anons need to be able to log in.
2366                         $whitelisted = true;
2367                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2368                         # Time to check the whitelist
2369                         # Only do these checks is there's something to check against
2370                         $name = $this->getPrefixedText();
2371                         $dbName = $this->getPrefixedDBkey();
2372
2373                         // Check for explicit whitelisting with and without underscores
2374                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2375                                 $whitelisted = true;
2376                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2377                                 # Old settings might have the title prefixed with
2378                                 # a colon for main-namespace pages
2379                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2380                                         $whitelisted = true;
2381                                 }
2382                         } elseif ( $this->isSpecialPage() ) {
2383                                 # If it's a special page, ditch the subpage bit and check again
2384                                 $name = $this->getDBkey();
2385                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2386                                 if ( $name ) {
2387                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2388                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2389                                                 $whitelisted = true;
2390                                         }
2391                                 }
2392                         }
2393                 }
2394
2395                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2396                         $name = $this->getPrefixedText();
2397                         // Check for regex whitelisting
2398                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2399                                 if ( preg_match( $listItem, $name ) ) {
2400                                         $whitelisted = true;
2401                                         break;
2402                                 }
2403                         }
2404                 }
2405
2406                 if ( !$whitelisted ) {
2407                         # If the title is not whitelisted, give extensions a chance to do so...
2408                         Hooks::run( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2409                         if ( !$whitelisted ) {
2410                                 $errors[] = $this->missingPermissionError( $action, $short );
2411                         }
2412                 }
2413
2414                 return $errors;
2415         }
2416
2417         /**
2418          * Get a description array when the user doesn't have the right to perform
2419          * $action (i.e. when User::isAllowed() returns false)
2420          *
2421          * @param string $action The action to check
2422          * @param bool $short Short circuit on first error
2423          * @return array List of errors
2424          */
2425         private function missingPermissionError( $action, $short ) {
2426                 // We avoid expensive display logic for quickUserCan's and such
2427                 if ( $short ) {
2428                         return array( 'badaccess-group0' );
2429                 }
2430
2431                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2432                         User::getGroupsWithPermission( $action ) );
2433
2434                 if ( count( $groups ) ) {
2435                         global $wgLang;
2436                         return array(
2437                                 'badaccess-groups',
2438                                 $wgLang->commaList( $groups ),
2439                                 count( $groups )
2440                         );
2441                 } else {
2442                         return array( 'badaccess-group0' );
2443                 }
2444         }
2445
2446         /**
2447          * Can $user perform $action on this page? This is an internal function,
2448          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2449          * checks on wfReadOnly() and blocks)
2450          *
2451          * @param string $action Action that permission needs to be checked for
2452          * @param User $user User to check
2453          * @param string $rigor One of (quick,full,secure)
2454          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
2455          *   - full   : does cheap and expensive checks possibly from a slave
2456          *   - secure : does cheap and expensive checks, using the master as needed
2457          * @param bool $short Set this to true to stop after the first permission error.
2458          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2459          */
2460         protected function getUserPermissionsErrorsInternal(
2461                 $action, $user, $rigor = 'secure', $short = false
2462         ) {
2463                 if ( $rigor === true ) {
2464                         $rigor = 'secure'; // b/c
2465                 } elseif ( $rigor === false ) {
2466                         $rigor = 'quick'; // b/c
2467                 } elseif ( !in_array( $rigor, array( 'quick', 'full', 'secure' ) ) ) {
2468                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2469                 }
2470
2471                 # Read has special handling
2472                 if ( $action == 'read' ) {
2473                         $checks = array(
2474                                 'checkPermissionHooks',
2475                                 'checkReadPermissions',
2476                         );
2477                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2478                 # here as it will lead to duplicate error messages. This is okay to do
2479                 # since anywhere that checks for create will also check for edit, and
2480                 # those checks are called for edit.
2481                 } elseif ( $action == 'create' ) {
2482                         $checks = array(
2483                                 'checkQuickPermissions',
2484                                 'checkPermissionHooks',
2485                                 'checkPageRestrictions',
2486                                 'checkCascadingSourcesRestrictions',
2487                                 'checkActionPermissions',
2488                                 'checkUserBlock'
2489                         );
2490                 } else {
2491                         $checks = array(
2492                                 'checkQuickPermissions',
2493                                 'checkPermissionHooks',
2494                                 'checkSpecialsAndNSPermissions',
2495                                 'checkCSSandJSPermissions',
2496                                 'checkPageRestrictions',
2497                                 'checkCascadingSourcesRestrictions',
2498                                 'checkActionPermissions',
2499                                 'checkUserBlock'
2500                         );
2501                 }
2502
2503                 $errors = array();
2504                 while ( count( $checks ) > 0 &&
2505                                 !( $short && count( $errors ) > 0 ) ) {
2506                         $method = array_shift( $checks );
2507                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2508                 }
2509
2510                 return $errors;
2511         }
2512
2513         /**
2514          * Get a filtered list of all restriction types supported by this wiki.
2515          * @param bool $exists True to get all restriction types that apply to
2516          * titles that do exist, False for all restriction types that apply to
2517          * titles that do not exist
2518          * @return array
2519          */
2520         public static function getFilteredRestrictionTypes( $exists = true ) {
2521                 global $wgRestrictionTypes;
2522                 $types = $wgRestrictionTypes;
2523                 if ( $exists ) {
2524                         # Remove the create restriction for existing titles
2525                         $types = array_diff( $types, array( 'create' ) );
2526                 } else {
2527                         # Only the create and upload restrictions apply to non-existing titles
2528                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2529                 }
2530                 return $types;
2531         }
2532
2533         /**
2534          * Returns restriction types for the current Title
2535          *
2536          * @return array Applicable restriction types
2537          */
2538         public function getRestrictionTypes() {
2539                 if ( $this->isSpecialPage() ) {
2540                         return array();
2541                 }
2542
2543                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2544
2545                 if ( $this->getNamespace() != NS_FILE ) {
2546                         # Remove the upload restriction for non-file titles
2547                         $types = array_diff( $types, array( 'upload' ) );
2548                 }
2549
2550                 Hooks::run( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2551
2552                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2553                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2554
2555                 return $types;
2556         }
2557
2558         /**
2559          * Is this title subject to title protection?
2560          * Title protection is the one applied against creation of such title.
2561          *
2562          * @return array|bool An associative array representing any existent title
2563          *   protection, or false if there's none.
2564          */
2565         public function getTitleProtection() {
2566                 // Can't protect pages in special namespaces
2567                 if ( $this->getNamespace() < 0 ) {
2568                         return false;
2569                 }
2570
2571                 // Can't protect pages that exist.
2572                 if ( $this->exists() ) {
2573                         return false;
2574                 }
2575
2576                 if ( $this->mTitleProtection === null ) {
2577                         $dbr = wfGetDB( DB_SLAVE );
2578                         $res = $dbr->select(
2579                                 'protected_titles',
2580                                 array(
2581                                         'user' => 'pt_user',
2582                                         'reason' => 'pt_reason',
2583                                         'expiry' => 'pt_expiry',
2584                                         'permission' => 'pt_create_perm'
2585                                 ),
2586                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2587                                 __METHOD__
2588                         );
2589
2590                         // fetchRow returns false if there are no rows.
2591                         $row = $dbr->fetchRow( $res );
2592                         if ( $row ) {
2593                                 if ( $row['permission'] == 'sysop' ) {
2594                                         $row['permission'] = 'editprotected'; // B/C
2595                                 }
2596                                 if ( $row['permission'] == 'autoconfirmed' ) {
2597                                         $row['permission'] = 'editsemiprotected'; // B/C
2598                                 }
2599                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2600                         }
2601                         $this->mTitleProtection = $row;
2602                 }
2603                 return $this->mTitleProtection;
2604         }
2605
2606         /**
2607          * Remove any title protection due to page existing
2608          */
2609         public function deleteTitleProtection() {
2610                 $dbw = wfGetDB( DB_MASTER );
2611
2612                 $dbw->delete(
2613                         'protected_titles',
2614                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2615                         __METHOD__
2616                 );
2617                 $this->mTitleProtection = false;
2618         }
2619
2620         /**
2621          * Is this page "semi-protected" - the *only* protection levels are listed
2622          * in $wgSemiprotectedRestrictionLevels?
2623          *
2624          * @param string $action Action to check (default: edit)
2625          * @return bool
2626          */
2627         public function isSemiProtected( $action = 'edit' ) {
2628                 global $wgSemiprotectedRestrictionLevels;
2629
2630                 $restrictions = $this->getRestrictions( $action );
2631                 $semi = $wgSemiprotectedRestrictionLevels;
2632                 if ( !$restrictions || !$semi ) {
2633                         // Not protected, or all protection is full protection
2634                         return false;
2635                 }
2636
2637                 // Remap autoconfirmed to editsemiprotected for BC
2638                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2639                         $semi[$key] = 'editsemiprotected';
2640                 }
2641                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2642                         $restrictions[$key] = 'editsemiprotected';
2643                 }
2644
2645                 return !array_diff( $restrictions, $semi );
2646         }
2647
2648         /**
2649          * Does the title correspond to a protected article?
2650          *
2651          * @param string $action The action the page is protected from,
2652          * by default checks all actions.
2653          * @return bool
2654          */
2655         public function isProtected( $action = '' ) {
2656                 global $wgRestrictionLevels;
2657
2658                 $restrictionTypes = $this->getRestrictionTypes();
2659
2660                 # Special pages have inherent protection
2661                 if ( $this->isSpecialPage() ) {
2662                         return true;
2663                 }
2664
2665                 # Check regular protection levels
2666                 foreach ( $restrictionTypes as $type ) {
2667                         if ( $action == $type || $action == '' ) {
2668                                 $r = $this->getRestrictions( $type );
2669                                 foreach ( $wgRestrictionLevels as $level ) {
2670                                         if ( in_array( $level, $r ) && $level != '' ) {
2671                                                 return true;
2672                                         }
2673                                 }
2674                         }
2675                 }
2676
2677                 return false;
2678         }
2679
2680         /**
2681          * Determines if $user is unable to edit this page because it has been protected
2682          * by $wgNamespaceProtection.
2683          *
2684          * @param User $user User object to check permissions
2685          * @return bool
2686          */
2687         public function isNamespaceProtected( User $user ) {
2688                 global $wgNamespaceProtection;
2689
2690                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2691                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2692                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2693                                         return true;
2694                                 }
2695                         }
2696                 }
2697                 return false;
2698         }
2699
2700         /**
2701          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2702          *
2703          * @return bool If the page is subject to cascading restrictions.
2704          */
2705         public function isCascadeProtected() {
2706                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2707                 return ( $sources > 0 );
2708         }
2709
2710         /**
2711          * Determines whether cascading protection sources have already been loaded from
2712          * the database.
2713          *
2714          * @param bool $getPages True to check if the pages are loaded, or false to check
2715          * if the status is loaded.
2716          * @return bool Whether or not the specified information has been loaded
2717          * @since 1.23
2718          */
2719         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2720                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2721         }
2722
2723         /**
2724          * Cascading protection: Get the source of any cascading restrictions on this page.
2725          *
2726          * @param bool $getPages Whether or not to retrieve the actual pages
2727          *        that the restrictions have come from and the actual restrictions
2728          *        themselves.
2729          * @return array Two elements: First is an array of Title objects of the
2730          *        pages from which cascading restrictions have come, false for
2731          *        none, or true if such restrictions exist but $getPages was not
2732          *        set. Second is an array like that returned by
2733          *        Title::getAllRestrictions(), or an empty array if $getPages is
2734          *        false.
2735          */
2736         public function getCascadeProtectionSources( $getPages = true ) {
2737                 $pagerestrictions = array();
2738
2739                 if ( $this->mCascadeSources !== null && $getPages ) {
2740                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2741                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2742                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2743                 }
2744
2745                 $dbr = wfGetDB( DB_SLAVE );
2746
2747                 if ( $this->getNamespace() == NS_FILE ) {
2748                         $tables = array( 'imagelinks', 'page_restrictions' );
2749                         $where_clauses = array(
2750                                 'il_to' => $this->getDBkey(),
2751                                 'il_from=pr_page',
2752                                 'pr_cascade' => 1
2753                         );
2754                 } else {
2755                         $tables = array( 'templatelinks', 'page_restrictions' );
2756                         $where_clauses = array(
2757                                 'tl_namespace' => $this->getNamespace(),
2758                                 'tl_title' => $this->getDBkey(),
2759                                 'tl_from=pr_page',
2760                                 'pr_cascade' => 1
2761                         );
2762                 }
2763
2764                 if ( $getPages ) {
2765                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2766                                 'pr_expiry', 'pr_type', 'pr_level' );
2767                         $where_clauses[] = 'page_id=pr_page';
2768                         $tables[] = 'page';
2769                 } else {
2770                         $cols = array( 'pr_expiry' );
2771                 }
2772
2773                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2774
2775                 $sources = $getPages ? array() : false;
2776                 $now = wfTimestampNow();
2777
2778                 foreach ( $res as $row ) {
2779                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2780                         if ( $expiry > $now ) {
2781                                 if ( $getPages ) {
2782                                         $page_id = $row->pr_page;
2783                                         $page_ns = $row->page_namespace;
2784                                         $page_title = $row->page_title;
2785                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2786                                         # Add groups needed for each restriction type if its not already there
2787                                         # Make sure this restriction type still exists
2788
2789                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2790                                                 $pagerestrictions[$row->pr_type] = array();
2791                                         }
2792
2793                                         if (
2794                                                 isset( $pagerestrictions[$row->pr_type] )
2795                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2796                                         ) {
2797                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2798                                         }
2799                                 } else {
2800                                         $sources = true;
2801                                 }
2802                         }
2803                 }
2804
2805                 if ( $getPages ) {
2806                         $this->mCascadeSources = $sources;
2807                         $this->mCascadingRestrictions = $pagerestrictions;
2808                 } else {
2809                         $this->mHasCascadingRestrictions = $sources;
2810                 }
2811
2812                 return array( $sources, $pagerestrictions );
2813         }
2814
2815         /**
2816          * Accessor for mRestrictionsLoaded
2817          *
2818          * @return bool Whether or not the page's restrictions have already been
2819          * loaded from the database
2820          * @since 1.23
2821          */
2822         public function areRestrictionsLoaded() {
2823                 return $this->mRestrictionsLoaded;
2824         }
2825
2826         /**
2827          * Accessor/initialisation for mRestrictions
2828          *
2829          * @param string $action Action that permission needs to be checked for
2830          * @return array Restriction levels needed to take the action. All levels are
2831          *     required. Note that restriction levels are normally user rights, but 'sysop'
2832          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2833          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2834          */
2835         public function getRestrictions( $action ) {
2836                 if ( !$this->mRestrictionsLoaded ) {
2837                         $this->loadRestrictions();
2838                 }
2839                 return isset( $this->mRestrictions[$action] )
2840                                 ? $this->mRestrictions[$action]
2841                                 : array();
2842         }
2843
2844         /**
2845          * Accessor/initialisation for mRestrictions
2846          *
2847          * @return array Keys are actions, values are arrays as returned by
2848          *     Title::getRestrictions()
2849          * @since 1.23
2850          */
2851         public function getAllRestrictions() {
2852                 if ( !$this->mRestrictionsLoaded ) {
2853                         $this->loadRestrictions();
2854                 }
2855                 return $this->mRestrictions;
2856         }
2857
2858         /**
2859          * Get the expiry time for the restriction against a given action
2860          *
2861          * @param string $action
2862          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2863          *     or not protected at all, or false if the action is not recognised.
2864          */
2865         public function getRestrictionExpiry( $action ) {
2866                 if ( !$this->mRestrictionsLoaded ) {
2867                         $this->loadRestrictions();
2868                 }
2869                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2870         }
2871
2872         /**
2873          * Returns cascading restrictions for the current article
2874          *
2875          * @return bool
2876          */
2877         function areRestrictionsCascading() {
2878                 if ( !$this->mRestrictionsLoaded ) {
2879                         $this->loadRestrictions();
2880                 }
2881
2882                 return $this->mCascadeRestriction;
2883         }
2884
2885         /**
2886          * Loads a string into mRestrictions array
2887          *
2888          * @param ResultWrapper $res Resource restrictions as an SQL result.
2889          * @param string $oldFashionedRestrictions Comma-separated list of page
2890          *        restrictions from page table (pre 1.10)
2891          */
2892         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2893                 $rows = array();
2894
2895                 foreach ( $res as $row ) {
2896                         $rows[] = $row;
2897                 }
2898
2899                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2900         }
2901
2902         /**
2903          * Compiles list of active page restrictions from both page table (pre 1.10)
2904          * and page_restrictions table for this existing page.
2905          * Public for usage by LiquidThreads.
2906          *
2907          * @param array $rows Array of db result objects
2908          * @param string $oldFashionedRestrictions Comma-separated list of page
2909          *   restrictions from page table (pre 1.10)
2910          */
2911         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2912                 $dbr = wfGetDB( DB_SLAVE );
2913
2914                 $restrictionTypes = $this->getRestrictionTypes();
2915
2916                 foreach ( $restrictionTypes as $type ) {
2917                         $this->mRestrictions[$type] = array();
2918                         $this->mRestrictionsExpiry[$type] = 'infinity';
2919                 }
2920
2921                 $this->mCascadeRestriction = false;
2922
2923                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2924                 if ( $oldFashionedRestrictions !== null ) {
2925                         $this->mOldRestrictions = $oldFashionedRestrictions;
2926                 }
2927
2928                 if ( $this->mOldRestrictions === false ) {
2929                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2930                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2931                 }
2932
2933                 if ( $this->mOldRestrictions != '' ) {
2934                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2935                                 $temp = explode( '=', trim( $restrict ) );
2936                                 if ( count( $temp ) == 1 ) {
2937                                         // old old format should be treated as edit/move restriction
2938                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2939                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2940                                 } else {
2941                                         $restriction = trim( $temp[1] );
2942                                         if ( $restriction != '' ) { // some old entries are empty
2943                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2944                                         }
2945                                 }
2946                         }
2947                 }
2948
2949                 if ( count( $rows ) ) {
2950                         # Current system - load second to make them override.
2951                         $now = wfTimestampNow();
2952
2953                         # Cycle through all the restrictions.
2954                         foreach ( $rows as $row ) {
2955
2956                                 // Don't take care of restrictions types that aren't allowed
2957                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2958                                         continue;
2959                                 }
2960
2961                                 // This code should be refactored, now that it's being used more generally,
2962                                 // But I don't really see any harm in leaving it in Block for now -werdna
2963                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2964
2965                                 // Only apply the restrictions if they haven't expired!
2966                                 if ( !$expiry || $expiry > $now ) {
2967                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2968                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2969
2970                                         $this->mCascadeRestriction |= $row->pr_cascade;
2971                                 }
2972                         }
2973                 }
2974
2975                 $this->mRestrictionsLoaded = true;
2976         }
2977
2978         /**
2979          * Load restrictions from the page_restrictions table
2980          *
2981          * @param string $oldFashionedRestrictions Comma-separated list of page
2982          *   restrictions from page table (pre 1.10)
2983          */
2984         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2985                 if ( !$this->mRestrictionsLoaded ) {
2986                         $dbr = wfGetDB( DB_SLAVE );
2987                         if ( $this->exists() ) {
2988                                 $res = $dbr->select(
2989                                         'page_restrictions',
2990                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2991                                         array( 'pr_page' => $this->getArticleID() ),
2992                                         __METHOD__
2993                                 );
2994
2995                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2996                         } else {
2997                                 $title_protection = $this->getTitleProtection();
2998
2999                                 if ( $title_protection ) {
3000                                         $now = wfTimestampNow();
3001                                         $expiry = $dbr->decodeExpiry( $title_protection['expiry'] );
3002
3003                                         if ( !$expiry || $expiry > $now ) {
3004                                                 // Apply the restrictions
3005                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3006                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
3007                                         } else { // Get rid of the old restrictions
3008                                                 $this->mTitleProtection = false;
3009                                         }
3010                                 } else {
3011                                         $this->mRestrictionsExpiry['create'] = 'infinity';
3012                                 }
3013                                 $this->mRestrictionsLoaded = true;
3014                         }
3015                 }
3016         }
3017
3018         /**
3019          * Flush the protection cache in this object and force reload from the database.
3020          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3021          */
3022         public function flushRestrictions() {
3023                 $this->mRestrictionsLoaded = false;
3024                 $this->mTitleProtection = null;
3025         }
3026
3027         /**
3028          * Purge expired restrictions from the page_restrictions table
3029          */
3030         static function purgeExpiredRestrictions() {
3031                 if ( wfReadOnly() ) {
3032                         return;
3033                 }
3034
3035                 DeferredUpdates::addUpdate( new AtomicSectionUpdate(
3036                         wfGetDB( DB_MASTER ),
3037                         __METHOD__,
3038                         function ( IDatabase $dbw, $fname ) {
3039                                 $dbw->delete(
3040                                         'page_restrictions',
3041                                         array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3042                                         $fname
3043                                 );
3044                                 $dbw->delete(
3045                                         'protected_titles',
3046                                         array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3047                                         $fname
3048                                 );
3049                         }
3050                 ) );
3051         }
3052
3053         /**
3054          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3055          *
3056          * @return bool
3057          */
3058         public function hasSubpages() {
3059                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3060                         # Duh
3061                         return false;
3062                 }
3063
3064                 # We dynamically add a member variable for the purpose of this method
3065                 # alone to cache the result.  There's no point in having it hanging
3066                 # around uninitialized in every Title object; therefore we only add it
3067                 # if needed and don't declare it statically.
3068                 if ( $this->mHasSubpages === null ) {
3069                         $this->mHasSubpages = false;
3070                         $subpages = $this->getSubpages( 1 );
3071                         if ( $subpages instanceof TitleArray ) {
3072                                 $this->mHasSubpages = (bool)$subpages->count();
3073                         }
3074                 }
3075
3076                 return $this->mHasSubpages;
3077         }
3078
3079         /**
3080          * Get all subpages of this page.
3081          *
3082          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3083          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3084          *  doesn't allow subpages
3085          */
3086         public function getSubpages( $limit = -1 ) {
3087                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3088                         return array();
3089                 }
3090
3091                 $dbr = wfGetDB( DB_SLAVE );
3092                 $conds['page_namespace'] = $this->getNamespace();
3093                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3094                 $options = array();
3095                 if ( $limit > -1 ) {
3096                         $options['LIMIT'] = $limit;
3097                 }
3098                 $this->mSubpages = TitleArray::newFromResult(
3099                         $dbr->select( 'page',
3100                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3101                                 $conds,
3102                                 __METHOD__,
3103                                 $options
3104                         )
3105                 );
3106                 return $this->mSubpages;
3107         }
3108
3109         /**
3110          * Is there a version of this page in the deletion archive?
3111          *
3112          * @return int The number of archived revisions
3113          */
3114         public function isDeleted() {
3115                 if ( $this->getNamespace() < 0 ) {
3116                         $n = 0;
3117                 } else {
3118                         $dbr = wfGetDB( DB_SLAVE );
3119
3120                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3121                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3122                                 __METHOD__
3123                         );
3124                         if ( $this->getNamespace() == NS_FILE ) {
3125                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3126                                         array( 'fa_name' => $this->getDBkey() ),
3127                                         __METHOD__
3128                                 );
3129                         }
3130                 }
3131                 return (int)$n;
3132         }
3133
3134         /**
3135          * Is there a version of this page in the deletion archive?
3136          *
3137          * @return bool
3138          */
3139         public function isDeletedQuick() {
3140                 if ( $this->getNamespace() < 0 ) {
3141                         return false;
3142                 }
3143                 $dbr = wfGetDB( DB_SLAVE );
3144                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3145                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3146                         __METHOD__
3147                 );
3148                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3149                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3150                                 array( 'fa_name' => $this->getDBkey() ),
3151                                 __METHOD__
3152                         );
3153                 }
3154                 return $deleted;
3155         }
3156
3157         /**
3158          * Get the article ID for this Title from the link cache,
3159          * adding it if necessary
3160          *
3161          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3162          *  for update
3163          * @return int The ID
3164          */
3165         public function getArticleID( $flags = 0 ) {
3166                 if ( $this->getNamespace() < 0 ) {
3167                         $this->mArticleID = 0;
3168                         return $this->mArticleID;
3169                 }
3170                 $linkCache = LinkCache::singleton();
3171                 if ( $flags & self::GAID_FOR_UPDATE ) {
3172                         $oldUpdate = $linkCache->forUpdate( true );
3173                         $linkCache->clearLink( $this );
3174                         $this->mArticleID = $linkCache->addLinkObj( $this );
3175                         $linkCache->forUpdate( $oldUpdate );
3176                 } else {
3177                         if ( -1 == $this->mArticleID ) {
3178                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3179                         }
3180                 }
3181                 return $this->mArticleID;
3182         }
3183
3184         /**
3185          * Is this an article that is a redirect page?
3186          * Uses link cache, adding it if necessary
3187          *
3188          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3189          * @return bool
3190          */
3191         public function isRedirect( $flags = 0 ) {
3192                 if ( !is_null( $this->mRedirect ) ) {
3193                         return $this->mRedirect;
3194                 }
3195                 if ( !$this->getArticleID( $flags ) ) {
3196                         $this->mRedirect = false;
3197                         return $this->mRedirect;
3198                 }
3199
3200                 $linkCache = LinkCache::singleton();
3201                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3202                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3203                 if ( $cached === null ) {
3204                         # Trust LinkCache's state over our own
3205                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3206                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3207                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3208                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3209                         # LinkCache to refresh its data from the master.
3210                         $this->mRedirect = false;
3211                         return $this->mRedirect;
3212                 }
3213
3214                 $this->mRedirect = (bool)$cached;
3215
3216                 return $this->mRedirect;
3217         }
3218
3219         /**
3220          * What is the length of this page?
3221          * Uses link cache, adding it if necessary
3222          *
3223          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3224          * @return int
3225          */
3226         public function getLength( $flags = 0 ) {
3227                 if ( $this->mLength != -1 ) {
3228                         return $this->mLength;
3229                 }
3230                 if ( !$this->getArticleID( $flags ) ) {
3231                         $this->mLength = 0;
3232                         return $this->mLength;
3233                 }
3234                 $linkCache = LinkCache::singleton();
3235                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3236                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3237                 if ( $cached === null ) {
3238                         # Trust LinkCache's state over our own, as for isRedirect()
3239                         $this->mLength = 0;
3240                         return $this->mLength;
3241                 }
3242
3243                 $this->mLength = intval( $cached );
3244
3245                 return $this->mLength;
3246         }
3247
3248         /**
3249          * What is the page_latest field for this page?
3250          *
3251          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3252          * @return int Int or 0 if the page doesn't exist
3253          */
3254         public function getLatestRevID( $flags = 0 ) {
3255                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3256                         return intval( $this->mLatestID );
3257                 }
3258                 if ( !$this->getArticleID( $flags ) ) {
3259                         $this->mLatestID = 0;
3260                         return $this->mLatestID;
3261                 }
3262                 $linkCache = LinkCache::singleton();
3263                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3264                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3265                 if ( $cached === null ) {
3266                         # Trust LinkCache's state over our own, as for isRedirect()
3267                         $this->mLatestID = 0;
3268                         return $this->mLatestID;
3269                 }
3270
3271                 $this->mLatestID = intval( $cached );
3272
3273                 return $this->mLatestID;
3274         }
3275
3276         /**
3277          * This clears some fields in this object, and clears any associated
3278          * keys in the "bad links" section of the link cache.
3279          *
3280          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3281          * loading of the new page_id. It's also called from
3282          * WikiPage::doDeleteArticleReal()
3283          *
3284          * @param int $newid The new Article ID
3285          */
3286         public function resetArticleID( $newid ) {
3287                 $linkCache = LinkCache::singleton();
3288                 $linkCache->clearLink( $this );
3289
3290                 if ( $newid === false ) {
3291                         $this->mArticleID = -1;
3292                 } else {
3293                         $this->mArticleID = intval( $newid );
3294                 }
3295                 $this->mRestrictionsLoaded = false;
3296                 $this->mRestrictions = array();
3297                 $this->mOldRestrictions = false;
3298                 $this->mRedirect = null;
3299                 $this->mLength = -1;
3300                 $this->mLatestID = false;
3301                 $this->mContentModel = false;
3302                 $this->mEstimateRevisions = null;
3303                 $this->mPageLanguage = false;
3304                 $this->mDbPageLanguage = null;
3305                 $this->mIsBigDeletion = null;
3306         }
3307
3308         public static function clearCaches() {
3309                 $linkCache = LinkCache::singleton();
3310                 $linkCache->clear();
3311
3312                 $titleCache = self::getTitleCache();
3313                 $titleCache->clear();
3314         }
3315
3316         /**
3317          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3318          *
3319          * @param string $text Containing title to capitalize
3320          * @param int $ns Namespace index, defaults to NS_MAIN
3321          * @return string Containing capitalized title
3322          */
3323         public static function capitalize( $text, $ns = NS_MAIN ) {
3324                 global $wgContLang;
3325
3326                 if ( MWNamespace::isCapitalized( $ns ) ) {
3327                         return $wgContLang->ucfirst( $text );
3328                 } else {
3329                         return $text;
3330                 }
3331         }
3332
3333         /**
3334          * Secure and split - main initialisation function for this object
3335          *
3336          * Assumes that mDbkeyform has been set, and is urldecoded
3337          * and uses underscores, but not otherwise munged.  This function
3338          * removes illegal characters, splits off the interwiki and
3339          * namespace prefixes, sets the other forms, and canonicalizes
3340          * everything.
3341          *
3342          * @throws MalformedTitleException On invalid titles
3343          * @return bool True on success
3344          */
3345         private function secureAndSplit() {
3346                 # Initialisation
3347                 $this->mInterwiki = '';
3348                 $this->mFragment = '';
3349                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3350
3351                 $dbkey = $this->mDbkeyform;
3352
3353                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3354                 //        the parsing code with Title, while avoiding massive refactoring.
3355                 // @todo: get rid of secureAndSplit, refactor parsing code.
3356                 $titleParser = self::getTitleParser();
3357                 // MalformedTitleException can be thrown here
3358                 $parts = $titleParser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3359
3360                 # Fill fields
3361                 $this->setFragment( '#' . $parts['fragment'] );
3362                 $this->mInterwiki = $parts['interwiki'];
3363                 $this->mLocalInterwiki = $parts['local_interwiki'];
3364                 $this->mNamespace = $parts['namespace'];
3365                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3366
3367                 $this->mDbkeyform = $parts['dbkey'];
3368                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3369                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3370
3371                 # We already know that some pages won't be in the database!
3372                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3373                         $this->mArticleID = 0;
3374                 }
3375
3376                 return true;
3377         }
3378
3379         /**
3380          * Get an array of Title objects linking to this Title
3381          * Also stores the IDs in the link cache.
3382          *
3383          * WARNING: do not use this function on arbitrary user-supplied titles!
3384          * On heavily-used templates it will max out the memory.
3385          *
3386          * @param array $options May be FOR UPDATE
3387          * @param string $table Table name
3388          * @param string $prefix Fields prefix
3389          * @return Title[] Array of Title objects linking here
3390          */
3391         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3392                 if ( count( $options ) > 0 ) {
3393                         $db = wfGetDB( DB_MASTER );
3394                 } else {
3395                         $db = wfGetDB( DB_SLAVE );
3396                 }
3397
3398                 $res = $db->select(
3399                         array( 'page', $table ),
3400                         self::getSelectFields(),
3401                         array(
3402                                 "{$prefix}_from=page_id",
3403                                 "{$prefix}_namespace" => $this->getNamespace(),
3404                                 "{$prefix}_title" => $this->getDBkey() ),
3405                         __METHOD__,
3406                         $options
3407                 );
3408
3409                 $retVal = array();
3410                 if ( $res->numRows() ) {
3411                         $linkCache = LinkCache::singleton();
3412                         foreach ( $res as $row ) {
3413                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3414                                 if ( $titleObj ) {
3415                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3416                                         $retVal[] = $titleObj;
3417                                 }
3418                         }
3419                 }
3420                 return $retVal;
3421         }
3422
3423         /**
3424          * Get an array of Title objects using this Title as a template
3425          * Also stores the IDs in the link cache.
3426          *
3427          * WARNING: do not use this function on arbitrary user-supplied titles!
3428          * On heavily-used templates it will max out the memory.
3429          *
3430          * @param array $options May be FOR UPDATE
3431          * @return Title[] Array of Title the Title objects linking here
3432          */
3433         public function getTemplateLinksTo( $options = array() ) {
3434                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3435         }
3436
3437         /**
3438          * Get an array of Title objects linked from this Title
3439          * Also stores the IDs in the link cache.
3440          *
3441          * WARNING: do not use this function on arbitrary user-supplied titles!
3442          * On heavily-used templates it will max out the memory.
3443          *
3444          * @param array $options May be FOR UPDATE
3445          * @param string $table Table name
3446          * @param string $prefix Fields prefix
3447          * @return array Array of Title objects linking here
3448          */
3449         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3450                 $id = $this->getArticleID();
3451
3452                 # If the page doesn't exist; there can't be any link from this page
3453                 if ( !$id ) {
3454                         return array();
3455                 }
3456
3457                 if ( count( $options ) > 0 ) {
3458                         $db = wfGetDB( DB_MASTER );
3459                 } else {
3460                         $db = wfGetDB( DB_SLAVE );
3461                 }
3462
3463                 $blNamespace = "{$prefix}_namespace";
3464                 $blTitle = "{$prefix}_title";
3465
3466                 $res = $db->select(
3467                         array( $table, 'page' ),
3468                         array_merge(
3469                                 array( $blNamespace, $blTitle ),
3470                                 WikiPage::selectFields()
3471                         ),
3472                         array( "{$prefix}_from" => $id ),
3473                         __METHOD__,
3474                         $options,
3475                         array( 'page' => array(
3476                                 'LEFT JOIN',
3477                                 array( "page_namespace=$blNamespace", "page_title=$blTitle" )
3478                         ) )
3479                 );
3480
3481                 $retVal = array();
3482                 $linkCache = LinkCache::singleton();
3483                 foreach ( $res as $row ) {
3484                         if ( $row->page_id ) {
3485                                 $titleObj = Title::newFromRow( $row );
3486                         } else {
3487                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3488                                 $linkCache->addBadLinkObj( $titleObj );
3489                         }
3490                         $retVal[] = $titleObj;
3491                 }
3492
3493                 return $retVal;
3494         }
3495
3496         /**
3497          * Get an array of Title objects used on this Title as a template
3498          * Also stores the IDs in the link cache.
3499          *
3500          * WARNING: do not use this function on arbitrary user-supplied titles!
3501          * On heavily-used templates it will max out the memory.
3502          *
3503          * @param array $options May be FOR UPDATE
3504          * @return Title[] Array of Title the Title objects used here
3505          */
3506         public function getTemplateLinksFrom( $options = array() ) {
3507                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3508         }
3509
3510         /**
3511          * Get an array of Title objects referring to non-existent articles linked
3512          * from this page.
3513          *
3514          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3515          *   should use redirect table in this case).
3516          * @return Title[] Array of Title the Title objects
3517          */
3518         public function getBrokenLinksFrom() {
3519                 if ( $this->getArticleID() == 0 ) {
3520                         # All links from article ID 0 are false positives
3521                         return array();
3522                 }
3523
3524                 $dbr = wfGetDB( DB_SLAVE );
3525                 $res = $dbr->select(
3526                         array( 'page', 'pagelinks' ),
3527                         array( 'pl_namespace', 'pl_title' ),
3528                         array(
3529                                 'pl_from' => $this->getArticleID(),
3530                                 'page_namespace IS NULL'
3531                         ),
3532                         __METHOD__, array(),
3533                         array(
3534                                 'page' => array(
3535                                         'LEFT JOIN',
3536                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3537                                 )
3538                         )
3539                 );
3540
3541                 $retVal = array();
3542                 foreach ( $res as $row ) {
3543                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3544                 }
3545                 return $retVal;
3546         }
3547
3548         /**
3549          * Get a list of URLs to purge from the CDN cache when this
3550          * page changes
3551          *
3552          * @return string[] Array of String the URLs
3553          */
3554         public function getCdnUrls() {
3555                 $urls = array(
3556                         $this->getInternalURL(),
3557                         $this->getInternalURL( 'action=history' )
3558                 );
3559
3560                 $pageLang = $this->getPageLanguage();
3561                 if ( $pageLang->hasVariants() ) {
3562                         $variants = $pageLang->getVariants();
3563                         foreach ( $variants as $vCode ) {
3564                                 $urls[] = $this->getInternalURL( $vCode );
3565                         }
3566                 }
3567
3568                 // If we are looking at a css/js user subpage, purge the action=raw.
3569                 if ( $this->isJsSubpage() ) {
3570                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3571                 } elseif ( $this->isCssSubpage() ) {
3572                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3573                 }
3574
3575                 Hooks::run( 'TitleSquidURLs', array( $this, &$urls ) );
3576                 return $urls;
3577         }
3578
3579         /**
3580          * @deprecated since 1.27 use getCdnUrls()
3581          */
3582         public function getSquidURLs() {
3583                 return $this->getCdnUrls();
3584         }
3585
3586         /**
3587          * Purge all applicable CDN URLs
3588          */
3589         public function purgeSquid() {
3590                 DeferredUpdates::addUpdate(
3591                         new CdnCacheUpdate( $this->getCdnUrls() ),
3592                         DeferredUpdates::PRESEND
3593                 );
3594         }
3595
3596         /**
3597          * Move this page without authentication
3598          *
3599          * @deprecated since 1.25 use MovePage class instead
3600          * @param Title $nt The new page Title
3601          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3602          */
3603         public function moveNoAuth( &$nt ) {
3604                 wfDeprecated( __METHOD__, '1.25' );
3605                 return $this->moveTo( $nt, false );
3606         }
3607
3608         /**
3609          * Check whether a given move operation would be valid.
3610          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3611          *
3612          * @deprecated since 1.25, use MovePage's methods instead
3613          * @param Title $nt The new title
3614          * @param bool $auth Whether to check user permissions (uses $wgUser)
3615          * @param string $reason Is the log summary of the move, used for spam checking
3616          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3617          */
3618         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3619                 global $wgUser;
3620
3621                 if ( !( $nt instanceof Title ) ) {
3622                         // Normally we'd add this to $errors, but we'll get
3623                         // lots of syntax errors if $nt is not an object
3624                         return array( array( 'badtitletext' ) );
3625                 }
3626
3627                 $mp = new MovePage( $this, $nt );
3628                 $errors = $mp->isValidMove()->getErrorsArray();
3629                 if ( $auth ) {
3630                         $errors = wfMergeErrorArrays(
3631                                 $errors,
3632                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3633                         );
3634                 }
3635
3636                 return $errors ?: true;
3637         }
3638
3639         /**
3640          * Check if the requested move target is a valid file move target
3641          * @todo move this to MovePage
3642          * @param Title $nt Target title
3643          * @return array List of errors
3644          */
3645         protected function validateFileMoveOperation( $nt ) {
3646                 global $wgUser;
3647
3648                 $errors = array();
3649
3650                 $destFile = wfLocalFile( $nt );
3651                 $destFile->load( File::READ_LATEST );
3652                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3653                         && !$destFile->exists() && wfFindFile( $nt )
3654                 ) {
3655                         $errors[] = array( 'file-exists-sharedrepo' );
3656                 }
3657
3658                 return $errors;
3659         }
3660
3661         /**
3662          * Move a title to a new location
3663          *
3664          * @deprecated since 1.25, use the MovePage class instead
3665          * @param Title $nt The new title
3666          * @param bool $auth Indicates whether $wgUser's permissions
3667          *  should be checked
3668          * @param string $reason The reason for the move
3669          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3670          *  Ignored if the user doesn't have the suppressredirect right.
3671          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3672          */
3673         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3674                 global $wgUser;
3675                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3676                 if ( is_array( $err ) ) {
3677                         // Auto-block user's IP if the account was "hard" blocked
3678                         $wgUser->spreadAnyEditBlock();
3679                         return $err;
3680                 }
3681                 // Check suppressredirect permission
3682                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3683                         $createRedirect = true;
3684                 }
3685
3686                 $mp = new MovePage( $this, $nt );
3687                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3688                 if ( $status->isOK() ) {
3689                         return true;
3690                 } else {
3691                         return $status->getErrorsArray();
3692                 }
3693         }
3694
3695         /**
3696          * Move this page's subpages to be subpages of $nt
3697          *
3698          * @param Title $nt Move target
3699          * @param bool $auth Whether $wgUser's permissions should be checked
3700          * @param string $reason The reason for the move
3701          * @param bool $createRedirect Whether to create redirects from the old subpages to
3702          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3703          * @return array Array with old page titles as keys, and strings (new page titles) or
3704          *     arrays (errors) as values, or an error array with numeric indices if no pages
3705          *     were moved
3706          */
3707         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3708                 global $wgMaximumMovedPages;
3709                 // Check permissions
3710                 if ( !$this->userCan( 'move-subpages' ) ) {
3711                         return array( 'cant-move-subpages' );
3712                 }
3713                 // Do the source and target namespaces support subpages?
3714                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3715                         return array( 'namespace-nosubpages',
3716                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3717                 }
3718                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3719                         return array( 'namespace-nosubpages',
3720                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3721                 }
3722
3723                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3724                 $retval = array();
3725                 $count = 0;
3726                 foreach ( $subpages as $oldSubpage ) {
3727                         $count++;
3728                         if ( $count > $wgMaximumMovedPages ) {
3729                                 $retval[$oldSubpage->getPrefixedText()] =
3730                                                 array( 'movepage-max-pages',
3731                                                         $wgMaximumMovedPages );
3732                                 break;
3733                         }
3734
3735                         // We don't know whether this function was called before
3736                         // or after moving the root page, so check both
3737                         // $this and $nt
3738                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3739                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3740                         ) {
3741                                 // When moving a page to a subpage of itself,
3742                                 // don't move it twice
3743                                 continue;
3744                         }
3745                         $newPageName = preg_replace(
3746                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3747                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3748                                         $oldSubpage->getDBkey() );
3749                         if ( $oldSubpage->isTalkPage() ) {
3750                                 $newNs = $nt->getTalkPage()->getNamespace();
3751                         } else {
3752                                 $newNs = $nt->getSubjectPage()->getNamespace();
3753                         }
3754                         # Bug 14385: we need makeTitleSafe because the new page names may
3755                         # be longer than 255 characters.
3756                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3757
3758                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3759                         if ( $success === true ) {
3760                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3761                         } else {
3762                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3763                         }
3764                 }
3765                 return $retval;
3766         }
3767
3768         /**
3769          * Checks if this page is just a one-rev redirect.
3770          * Adds lock, so don't use just for light purposes.
3771          *
3772          * @return bool
3773          */
3774         public function isSingleRevRedirect() {
3775                 global $wgContentHandlerUseDB;
3776
3777                 $dbw = wfGetDB( DB_MASTER );
3778
3779                 # Is it a redirect?
3780                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
3781                 if ( $wgContentHandlerUseDB ) {
3782                         $fields[] = 'page_content_model';
3783                 }
3784
3785                 $row = $dbw->selectRow( 'page',
3786                         $fields,
3787                         $this->pageCond(),
3788                         __METHOD__,
3789                         array( 'FOR UPDATE' )
3790                 );
3791                 # Cache some fields we may want
3792                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3793                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3794                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3795                 $this->mContentModel = $row && isset( $row->page_content_model )
3796                         ? strval( $row->page_content_model )
3797                         : false;
3798
3799                 if ( !$this->mRedirect ) {
3800                         return false;
3801                 }
3802                 # Does the article have a history?
3803                 $row = $dbw->selectField( array( 'page', 'revision' ),
3804                         'rev_id',
3805                         array( 'page_namespace' => $this->getNamespace(),
3806                                 'page_title' => $this->getDBkey(),
3807                                 'page_id=rev_page',
3808                                 'page_latest != rev_id'
3809                         ),
3810                         __METHOD__,
3811                         array( 'FOR UPDATE' )
3812                 );
3813                 # Return true if there was no history
3814                 return ( $row === false );
3815         }
3816
3817         /**
3818          * Checks if $this can be moved to a given Title
3819          * - Selects for update, so don't call it unless you mean business
3820          *
3821          * @deprecated since 1.25, use MovePage's methods instead
3822          * @param Title $nt The new title to check
3823          * @return bool
3824          */
3825         public function isValidMoveTarget( $nt ) {
3826                 # Is it an existing file?
3827                 if ( $nt->getNamespace() == NS_FILE ) {
3828                         $file = wfLocalFile( $nt );
3829                         $file->load( File::READ_LATEST );
3830                         if ( $file->exists() ) {
3831                                 wfDebug( __METHOD__ . ": file exists\n" );
3832                                 return false;
3833                         }
3834                 }
3835                 # Is it a redirect with no history?
3836                 if ( !$nt->isSingleRevRedirect() ) {
3837                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3838                         return false;
3839                 }
3840                 # Get the article text
3841                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3842                 if ( !is_object( $rev ) ) {
3843                         return false;
3844                 }
3845                 $content = $rev->getContent();
3846                 # Does the redirect point to the source?
3847                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3848                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3849
3850                 if ( $redirTitle ) {
3851                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3852                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3853                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3854                                 return false;
3855                         } else {
3856                                 return true;
3857                         }
3858                 } else {
3859                         # Fail safe (not a redirect after all. strange.)
3860                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3861                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3862                         return false;
3863                 }
3864         }
3865
3866         /**
3867          * Get categories to which this Title belongs and return an array of
3868          * categories' names.
3869          *
3870          * @return array Array of parents in the form:
3871          *        $parent => $currentarticle
3872          */
3873         public function getParentCategories() {
3874                 global $wgContLang;
3875
3876                 $data = array();
3877
3878                 $titleKey = $this->getArticleID();
3879
3880                 if ( $titleKey === 0 ) {
3881                         return $data;
3882                 }
3883
3884                 $dbr = wfGetDB( DB_SLAVE );
3885
3886                 $res = $dbr->select(
3887                         'categorylinks',
3888                         'cl_to',
3889                         array( 'cl_from' => $titleKey ),
3890                         __METHOD__
3891                 );
3892
3893                 if ( $res->numRows() > 0 ) {
3894                         foreach ( $res as $row ) {
3895                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3896                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3897                         }
3898                 }
3899                 return $data;
3900         }
3901
3902         /**
3903          * Get a tree of parent categories
3904          *
3905          * @param array $children Array with the children in the keys, to check for circular refs
3906          * @return array Tree of parent categories
3907          */
3908         public function getParentCategoryTree( $children = array() ) {
3909                 $stack = array();
3910                 $parents = $this->getParentCategories();
3911
3912                 if ( $parents ) {
3913                         foreach ( $parents as $parent => $current ) {
3914                                 if ( array_key_exists( $parent, $children ) ) {
3915                                         # Circular reference
3916                                         $stack[$parent] = array();
3917                                 } else {
3918                                         $nt = Title::newFromText( $parent );
3919                                         if ( $nt ) {
3920                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
3921                                         }
3922                                 }
3923                         }
3924                 }
3925
3926                 return $stack;
3927         }
3928
3929         /**
3930          * Get an associative array for selecting this title from
3931          * the "page" table
3932          *
3933          * @return array Array suitable for the $where parameter of DB::select()
3934          */
3935         public function pageCond() {
3936                 if ( $this->mArticleID > 0 ) {
3937                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3938                         return array( 'page_id' => $this->mArticleID );
3939                 } else {
3940                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
3941                 }
3942         }
3943
3944         /**
3945          * Get the revision ID of the previous revision
3946          *
3947          * @param int $revId Revision ID. Get the revision that was before this one.
3948          * @param int $flags Title::GAID_FOR_UPDATE
3949          * @return int|bool Old revision ID, or false if none exists
3950          */
3951         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3952                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3953                 $revId = $db->selectField( 'revision', 'rev_id',
3954                         array(
3955                                 'rev_page' => $this->getArticleID( $flags ),
3956                                 'rev_id < ' . intval( $revId )
3957                         ),
3958                         __METHOD__,
3959                         array( 'ORDER BY' => 'rev_id DESC' )
3960                 );
3961
3962                 if ( $revId === false ) {
3963                         return false;
3964                 } else {
3965                         return intval( $revId );
3966                 }
3967         }
3968
3969         /**
3970          * Get the revision ID of the next revision
3971          *
3972          * @param int $revId Revision ID. Get the revision that was after this one.
3973          * @param int $flags Title::GAID_FOR_UPDATE
3974          * @return int|bool Next revision ID, or false if none exists
3975          */
3976         public function getNextRevisionID( $revId, $flags = 0 ) {
3977                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3978                 $revId = $db->selectField( 'revision', 'rev_id',
3979                         array(
3980                                 'rev_page' => $this->getArticleID( $flags ),
3981                                 'rev_id > ' . intval( $revId )
3982                         ),
3983                         __METHOD__,
3984                         array( 'ORDER BY' => 'rev_id' )
3985                 );
3986
3987                 if ( $revId === false ) {
3988                         return false;
3989                 } else {
3990                         return intval( $revId );
3991                 }
3992         }
3993
3994         /**
3995          * Get the first revision of the page
3996          *
3997          * @param int $flags Title::GAID_FOR_UPDATE
3998          * @return Revision|null If page doesn't exist
3999          */
4000         public function getFirstRevision( $flags = 0 ) {
4001                 $pageId = $this->getArticleID( $flags );
4002                 if ( $pageId ) {
4003                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4004                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4005                                 array( 'rev_page' => $pageId ),
4006                                 __METHOD__,
4007                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4008                         );
4009                         if ( $row ) {
4010                                 return new Revision( $row );
4011                         }
4012                 }
4013                 return null;
4014         }
4015
4016         /**
4017          * Get the oldest revision timestamp of this page
4018          *
4019          * @param int $flags Title::GAID_FOR_UPDATE
4020          * @return string MW timestamp
4021          */
4022         public function getEarliestRevTime( $flags = 0 ) {
4023                 $rev = $this->getFirstRevision( $flags );
4024                 return $rev ? $rev->getTimestamp() : null;
4025         }
4026
4027         /**
4028          * Check if this is a new page
4029          *
4030          * @return bool
4031          */
4032         public function isNewPage() {
4033                 $dbr = wfGetDB( DB_SLAVE );
4034                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4035         }
4036
4037         /**
4038          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4039          *
4040          * @return bool
4041          */
4042         public function isBigDeletion() {
4043                 global $wgDeleteRevisionsLimit;
4044
4045                 if ( !$wgDeleteRevisionsLimit ) {
4046                         return false;
4047                 }
4048
4049                 if ( $this->mIsBigDeletion === null ) {
4050                         $dbr = wfGetDB( DB_SLAVE );
4051
4052                         $revCount = $dbr->selectRowCount(
4053                                 'revision',
4054                                 '1',
4055                                 array( 'rev_page' => $this->getArticleID() ),
4056                                 __METHOD__,
4057                                 array( 'LIMIT' => $wgDeleteRevisionsLimit + 1 )
4058                         );
4059
4060                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4061                 }
4062
4063                 return $this->mIsBigDeletion;
4064         }
4065
4066         /**
4067          * Get the approximate revision count of this page.
4068          *
4069          * @return int
4070          */
4071         public function estimateRevisionCount() {
4072                 if ( !$this->exists() ) {
4073                         return 0;
4074                 }
4075
4076                 if ( $this->mEstimateRevisions === null ) {
4077                         $dbr = wfGetDB( DB_SLAVE );
4078                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4079                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4080                 }
4081
4082                 return $this->mEstimateRevisions;
4083         }
4084
4085         /**
4086          * Get the number of revisions between the given revision.
4087          * Used for diffs and other things that really need it.
4088          *
4089          * @param int|Revision $old Old revision or rev ID (first before range)
4090          * @param int|Revision $new New revision or rev ID (first after range)
4091          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4092          * @return int Number of revisions between these revisions.
4093          */
4094         public function countRevisionsBetween( $old, $new, $max = null ) {
4095                 if ( !( $old instanceof Revision ) ) {
4096                         $old = Revision::newFromTitle( $this, (int)$old );
4097                 }
4098                 if ( !( $new instanceof Revision ) ) {
4099                         $new = Revision::newFromTitle( $this, (int)$new );
4100                 }
4101                 if ( !$old || !$new ) {
4102                         return 0; // nothing to compare
4103                 }
4104                 $dbr = wfGetDB( DB_SLAVE );
4105                 $conds = array(
4106                         'rev_page' => $this->getArticleID(),
4107                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4108                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4109                 );
4110                 if ( $max !== null ) {
4111                         return $dbr->selectRowCount( 'revision', '1',
4112                                 $conds,
4113                                 __METHOD__,
4114                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4115                         );
4116                 } else {
4117                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4118                 }
4119         }
4120
4121         /**
4122          * Get the authors between the given revisions or revision IDs.
4123          * Used for diffs and other things that really need it.
4124          *
4125          * @since 1.23
4126          *
4127          * @param int|Revision $old Old revision or rev ID (first before range by default)
4128          * @param int|Revision $new New revision or rev ID (first after range by default)
4129          * @param int $limit Maximum number of authors
4130          * @param string|array $options (Optional): Single option, or an array of options:
4131          *     'include_old' Include $old in the range; $new is excluded.
4132          *     'include_new' Include $new in the range; $old is excluded.
4133          *     'include_both' Include both $old and $new in the range.
4134          *     Unknown option values are ignored.
4135          * @return array|null Names of revision authors in the range; null if not both revisions exist
4136          */
4137         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4138                 if ( !( $old instanceof Revision ) ) {
4139                         $old = Revision::newFromTitle( $this, (int)$old );
4140                 }
4141                 if ( !( $new instanceof Revision ) ) {
4142                         $new = Revision::newFromTitle( $this, (int)$new );
4143                 }
4144                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4145                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4146                 // in the sanity check below?
4147                 if ( !$old || !$new ) {
4148                         return null; // nothing to compare
4149                 }
4150                 $authors = array();
4151                 $old_cmp = '>';
4152                 $new_cmp = '<';
4153                 $options = (array)$options;
4154                 if ( in_array( 'include_old', $options ) ) {
4155                         $old_cmp = '>=';
4156                 }
4157                 if ( in_array( 'include_new', $options ) ) {
4158                         $new_cmp = '<=';
4159                 }
4160                 if ( in_array( 'include_both', $options ) ) {
4161                         $old_cmp = '>=';
4162                         $new_cmp = '<=';
4163                 }
4164                 // No DB query needed if $old and $new are the same or successive revisions:
4165                 if ( $old->getId() === $new->getId() ) {
4166                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4167                                 array() :
4168                                 array( $old->getUserText( Revision::RAW ) );
4169                 } elseif ( $old->getId() === $new->getParentId() ) {
4170                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4171                                 $authors[] = $old->getUserText( Revision::RAW );
4172                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4173                                         $authors[] = $new->getUserText( Revision::RAW );
4174                                 }
4175                         } elseif ( $old_cmp === '>=' ) {
4176                                 $authors[] = $old->getUserText( Revision::RAW );
4177                         } elseif ( $new_cmp === '<=' ) {
4178                                 $authors[] = $new->getUserText( Revision::RAW );
4179                         }
4180                         return $authors;
4181                 }
4182                 $dbr = wfGetDB( DB_SLAVE );
4183                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4184                         array(
4185                                 'rev_page' => $this->getArticleID(),
4186                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4187                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4188                         ), __METHOD__,
4189                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4190                 );
4191                 foreach ( $res as $row ) {
4192                         $authors[] = $row->rev_user_text;
4193                 }
4194                 return $authors;
4195         }
4196
4197         /**
4198          * Get the number of authors between the given revisions or revision IDs.
4199          * Used for diffs and other things that really need it.
4200          *
4201          * @param int|Revision $old Old revision or rev ID (first before range by default)
4202          * @param int|Revision $new New revision or rev ID (first after range by default)
4203          * @param int $limit Maximum number of authors
4204          * @param string|array $options (Optional): Single option, or an array of options:
4205          *     'include_old' Include $old in the range; $new is excluded.
4206          *     'include_new' Include $new in the range; $old is excluded.
4207          *     'include_both' Include both $old and $new in the range.
4208          *     Unknown option values are ignored.
4209          * @return int Number of revision authors in the range; zero if not both revisions exist
4210          */
4211         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4212                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4213                 return $authors ? count( $authors ) : 0;
4214         }
4215
4216         /**
4217          * Compare with another title.
4218          *
4219          * @param Title $title
4220          * @return bool
4221          */
4222         public function equals( Title $title ) {
4223                 // Note: === is necessary for proper matching of number-like titles.
4224                 return $this->getInterwiki() === $title->getInterwiki()
4225                         && $this->getNamespace() == $title->getNamespace()
4226                         && $this->getDBkey() === $title->getDBkey();
4227         }
4228
4229         /**
4230          * Check if this title is a subpage of another title
4231          *
4232          * @param Title $title
4233          * @return bool
4234          */
4235         public function isSubpageOf( Title $title ) {
4236                 return $this->getInterwiki() === $title->getInterwiki()
4237                         && $this->getNamespace() == $title->getNamespace()
4238                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4239         }
4240
4241         /**
4242          * Check if page exists.  For historical reasons, this function simply
4243          * checks for the existence of the title in the page table, and will
4244          * thus return false for interwiki links, special pages and the like.
4245          * If you want to know if a title can be meaningfully viewed, you should
4246          * probably call the isKnown() method instead.
4247          *
4248          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4249          *   from master/for update
4250          * @return bool
4251          */
4252         public function exists( $flags = 0 ) {
4253                 $exists = $this->getArticleID( $flags ) != 0;
4254                 Hooks::run( 'TitleExists', array( $this, &$exists ) );
4255                 return $exists;
4256         }
4257
4258         /**
4259          * Should links to this title be shown as potentially viewable (i.e. as
4260          * "bluelinks"), even if there's no record by this title in the page
4261          * table?
4262          *
4263          * This function is semi-deprecated for public use, as well as somewhat
4264          * misleadingly named.  You probably just want to call isKnown(), which
4265          * calls this function internally.
4266          *
4267          * (ISSUE: Most of these checks are cheap, but the file existence check
4268          * can potentially be quite expensive.  Including it here fixes a lot of
4269          * existing code, but we might want to add an optional parameter to skip
4270          * it and any other expensive checks.)
4271          *
4272          * @return bool
4273          */
4274         public function isAlwaysKnown() {
4275                 $isKnown = null;
4276
4277                 /**
4278                  * Allows overriding default behavior for determining if a page exists.
4279                  * If $isKnown is kept as null, regular checks happen. If it's
4280                  * a boolean, this value is returned by the isKnown method.
4281                  *
4282                  * @since 1.20
4283                  *
4284                  * @param Title $title
4285                  * @param bool|null $isKnown
4286                  */
4287                 Hooks::run( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4288
4289                 if ( !is_null( $isKnown ) ) {
4290                         return $isKnown;
4291                 }
4292
4293                 if ( $this->isExternal() ) {
4294                         return true;  // any interwiki link might be viewable, for all we know
4295                 }
4296
4297                 switch ( $this->mNamespace ) {
4298                         case NS_MEDIA:
4299                         case NS_FILE:
4300                                 // file exists, possibly in a foreign repo
4301                                 return (bool)wfFindFile( $this );
4302                         case NS_SPECIAL:
4303                                 // valid special page
4304                                 return SpecialPageFactory::exists( $this->getDBkey() );
4305                         case NS_MAIN:
4306                                 // selflink, possibly with fragment
4307                                 return $this->mDbkeyform == '';
4308                         case NS_MEDIAWIKI:
4309                                 // known system message
4310                                 return $this->hasSourceText() !== false;
4311                         default:
4312                                 return false;
4313                 }
4314         }
4315
4316         /**
4317          * Does this title refer to a page that can (or might) be meaningfully
4318          * viewed?  In particular, this function may be used to determine if
4319          * links to the title should be rendered as "bluelinks" (as opposed to
4320          * "redlinks" to non-existent pages).
4321          * Adding something else to this function will cause inconsistency
4322          * since LinkHolderArray calls isAlwaysKnown() and does its own
4323          * page existence check.
4324          *
4325          * @return bool
4326          */
4327         public function isKnown() {
4328                 return $this->isAlwaysKnown() || $this->exists();
4329         }
4330
4331         /**
4332          * Does this page have source text?
4333          *
4334          * @return bool
4335          */
4336         public function hasSourceText() {
4337                 if ( $this->exists() ) {
4338                         return true;
4339                 }
4340
4341                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4342                         // If the page doesn't exist but is a known system message, default
4343                         // message content will be displayed, same for language subpages-
4344                         // Use always content language to avoid loading hundreds of languages
4345                         // to get the link color.
4346                         global $wgContLang;
4347                         list( $name, ) = MessageCache::singleton()->figureMessage(
4348                                 $wgContLang->lcfirst( $this->getText() )
4349                         );
4350                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4351                         return $message->exists();
4352                 }
4353
4354                 return false;
4355         }
4356
4357         /**
4358          * Get the default message text or false if the message doesn't exist
4359          *
4360          * @return string|bool
4361          */
4362         public function getDefaultMessageText() {
4363                 global $wgContLang;
4364
4365                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4366                         return false;
4367                 }
4368
4369                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4370                         $wgContLang->lcfirst( $this->getText() )
4371                 );
4372                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4373
4374                 if ( $message->exists() ) {
4375                         return $message->plain();
4376                 } else {
4377                         return false;
4378                 }
4379         }
4380
4381         /**
4382          * Updates page_touched for this page; called from LinksUpdate.php
4383          *
4384          * @param string $purgeTime [optional] TS_MW timestamp
4385          * @return bool True if the update succeeded
4386          */
4387         public function invalidateCache( $purgeTime = null ) {
4388                 if ( wfReadOnly() ) {
4389                         return false;
4390                 }
4391
4392                 if ( $this->mArticleID === 0 ) {
4393                         return true; // avoid gap locking if we know it's not there
4394                 }
4395
4396                 $method = __METHOD__;
4397                 $dbw = wfGetDB( DB_MASTER );
4398                 $conds = $this->pageCond();
4399                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method, $purgeTime ) {
4400                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4401
4402                         $dbw->update(
4403                                 'page',
4404                                 array( 'page_touched' => $dbTimestamp ),
4405                                 $conds + array( 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ),
4406                                 $method
4407                         );
4408                 } );
4409
4410                 return true;
4411         }
4412
4413         /**
4414          * Update page_touched timestamps and send CDN purge messages for
4415          * pages linking to this title. May be sent to the job queue depending
4416          * on the number of links. Typically called on create and delete.
4417          */
4418         public function touchLinks() {
4419                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4420                 if ( $this->getNamespace() == NS_CATEGORY ) {
4421                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4422                 }
4423         }
4424
4425         /**
4426          * Get the last touched timestamp
4427          *
4428          * @param IDatabase $db Optional db
4429          * @return string Last-touched timestamp
4430          */
4431         public function getTouched( $db = null ) {
4432                 if ( $db === null ) {
4433                         $db = wfGetDB( DB_SLAVE );
4434                 }
4435                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4436                 return $touched;
4437         }
4438
4439         /**
4440          * Get the timestamp when this page was updated since the user last saw it.
4441          *
4442          * @param User $user
4443          * @return string|null
4444          */
4445         public function getNotificationTimestamp( $user = null ) {
4446                 global $wgUser;
4447
4448                 // Assume current user if none given
4449                 if ( !$user ) {
4450                         $user = $wgUser;
4451                 }
4452                 // Check cache first
4453                 $uid = $user->getId();
4454                 if ( !$uid ) {
4455                         return false;
4456                 }
4457                 // avoid isset here, as it'll return false for null entries
4458                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4459                         return $this->mNotificationTimestamp[$uid];
4460                 }
4461                 // Don't cache too much!
4462                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4463                         $this->mNotificationTimestamp = array();
4464                 }
4465
4466                 $watchedItem = WatchedItem::fromUserTitle( $user, $this );
4467                 $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4468
4469                 return $this->mNotificationTimestamp[$uid];
4470         }
4471
4472         /**
4473          * Generate strings used for xml 'id' names in monobook tabs
4474          *
4475          * @param string $prepend Defaults to 'nstab-'
4476          * @return string XML 'id' name
4477          */
4478         public function getNamespaceKey( $prepend = 'nstab-' ) {
4479                 global $wgContLang;
4480                 // Gets the subject namespace if this title
4481                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4482                 // Checks if canonical namespace name exists for namespace
4483                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4484                         // Uses canonical namespace name
4485                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4486                 } else {
4487                         // Uses text of namespace
4488                         $namespaceKey = $this->getSubjectNsText();
4489                 }
4490                 // Makes namespace key lowercase
4491                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4492                 // Uses main
4493                 if ( $namespaceKey == '' ) {
4494                         $namespaceKey = 'main';
4495                 }
4496                 // Changes file to image for backwards compatibility
4497                 if ( $namespaceKey == 'file' ) {
4498                         $namespaceKey = 'image';
4499                 }
4500                 return $prepend . $namespaceKey;
4501         }
4502
4503         /**
4504          * Get all extant redirects to this Title
4505          *
4506          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4507          * @return Title[] Array of Title redirects to this title
4508          */
4509         public function getRedirectsHere( $ns = null ) {
4510                 $redirs = array();
4511
4512                 $dbr = wfGetDB( DB_SLAVE );
4513                 $where = array(
4514                         'rd_namespace' => $this->getNamespace(),
4515                         'rd_title' => $this->getDBkey(),
4516                         'rd_from = page_id'
4517                 );
4518                 if ( $this->isExternal() ) {
4519                         $where['rd_interwiki'] = $this->getInterwiki();
4520                 } else {
4521                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4522                 }
4523                 if ( !is_null( $ns ) ) {
4524                         $where['page_namespace'] = $ns;
4525                 }
4526
4527                 $res = $dbr->select(
4528                         array( 'redirect', 'page' ),
4529                         array( 'page_namespace', 'page_title' ),
4530                         $where,
4531                         __METHOD__
4532                 );
4533
4534                 foreach ( $res as $row ) {
4535                         $redirs[] = self::newFromRow( $row );
4536                 }
4537                 return $redirs;
4538         }
4539
4540         /**
4541          * Check if this Title is a valid redirect target
4542          *
4543          * @return bool
4544          */
4545         public function isValidRedirectTarget() {
4546                 global $wgInvalidRedirectTargets;
4547
4548                 if ( $this->isSpecialPage() ) {
4549                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4550                         if ( $this->isSpecial( 'Userlogout' ) ) {
4551                                 return false;
4552                         }
4553
4554                         foreach ( $wgInvalidRedirectTargets as $target ) {
4555                                 if ( $this->isSpecial( $target ) ) {
4556                                         return false;
4557                                 }
4558                         }
4559                 }
4560
4561                 return true;
4562         }
4563
4564         /**
4565          * Get a backlink cache object
4566          *
4567          * @return BacklinkCache
4568          */
4569         public function getBacklinkCache() {
4570                 return BacklinkCache::get( $this );
4571         }
4572
4573         /**
4574          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4575          *
4576          * @return bool
4577          */
4578         public function canUseNoindex() {
4579                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4580
4581                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4582                         ? $wgContentNamespaces
4583                         : $wgExemptFromUserRobotsControl;
4584
4585                 return !in_array( $this->mNamespace, $bannedNamespaces );
4586
4587         }
4588
4589         /**
4590          * Returns the raw sort key to be used for categories, with the specified
4591          * prefix.  This will be fed to Collation::getSortKey() to get a
4592          * binary sortkey that can be used for actual sorting.
4593          *
4594          * @param string $prefix The prefix to be used, specified using
4595          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4596          *   prefix.
4597          * @return string
4598          */
4599         public function getCategorySortkey( $prefix = '' ) {
4600                 $unprefixed = $this->getText();
4601
4602                 // Anything that uses this hook should only depend
4603                 // on the Title object passed in, and should probably
4604                 // tell the users to run updateCollations.php --force
4605                 // in order to re-sort existing category relations.
4606                 Hooks::run( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4607                 if ( $prefix !== '' ) {
4608                         # Separate with a line feed, so the unprefixed part is only used as
4609                         # a tiebreaker when two pages have the exact same prefix.
4610                         # In UCA, tab is the only character that can sort above LF
4611                         # so we strip both of them from the original prefix.
4612                         $prefix = strtr( $prefix, "\n\t", '  ' );
4613                         return "$prefix\n$unprefixed";
4614                 }
4615                 return $unprefixed;
4616         }
4617
4618         /**
4619          * Get the language in which the content of this page is written in
4620          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4621          * e.g. $wgLang (such as special pages, which are in the user language).
4622          *
4623          * @since 1.18
4624          * @return Language
4625          */
4626         public function getPageLanguage() {
4627                 global $wgLang, $wgLanguageCode;
4628                 if ( $this->isSpecialPage() ) {
4629                         // special pages are in the user language
4630                         return $wgLang;
4631                 }
4632
4633                 // Checking if DB language is set
4634                 if ( $this->mDbPageLanguage ) {
4635                         return wfGetLangObj( $this->mDbPageLanguage );
4636                 }
4637
4638                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4639                         // Note that this may depend on user settings, so the cache should
4640                         // be only per-request.
4641                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4642                         // content to determine the page language!
4643                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4644                         // tests.
4645                         $contentHandler = ContentHandler::getForTitle( $this );
4646                         $langObj = $contentHandler->getPageLanguage( $this );
4647                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4648                 } else {
4649                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4650                 }
4651
4652                 return $langObj;
4653         }
4654
4655         /**
4656          * Get the language in which the content of this page is written when
4657          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4658          * e.g. $wgLang (such as special pages, which are in the user language).
4659          *
4660          * @since 1.20
4661          * @return Language
4662          */
4663         public function getPageViewLanguage() {
4664                 global $wgLang;
4665
4666                 if ( $this->isSpecialPage() ) {
4667                         // If the user chooses a variant, the content is actually
4668                         // in a language whose code is the variant code.
4669                         $variant = $wgLang->getPreferredVariant();
4670                         if ( $wgLang->getCode() !== $variant ) {
4671                                 return Language::factory( $variant );
4672                         }
4673
4674                         return $wgLang;
4675                 }
4676
4677                 // @note Can't be cached persistently, depends on user settings.
4678                 // @note ContentHandler::getPageViewLanguage() may need to load the
4679                 //   content to determine the page language!
4680                 $contentHandler = ContentHandler::getForTitle( $this );
4681                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4682                 return $pageLang;
4683         }
4684
4685         /**
4686          * Get a list of rendered edit notices for this page.
4687          *
4688          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4689          * they will already be wrapped in paragraphs.
4690          *
4691          * @since 1.21
4692          * @param int $oldid Revision ID that's being edited
4693          * @return array
4694          */
4695         public function getEditNotices( $oldid = 0 ) {
4696                 $notices = array();
4697
4698                 // Optional notice for the entire namespace
4699                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4700                 $msg = wfMessage( $editnotice_ns );
4701                 if ( $msg->exists() ) {
4702                         $html = $msg->parseAsBlock();
4703                         // Edit notices may have complex logic, but output nothing (T91715)
4704                         if ( trim( $html ) !== '' ) {
4705                                 $notices[$editnotice_ns] = Html::rawElement(
4706                                         'div',
4707                                         array( 'class' => array(
4708                                                 'mw-editnotice',
4709                                                 'mw-editnotice-namespace',
4710                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4711                                         ) ),
4712                                         $html
4713                                 );
4714                         }
4715                 }
4716
4717                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4718                         // Optional notice for page itself and any parent page
4719                         $parts = explode( '/', $this->getDBkey() );
4720                         $editnotice_base = $editnotice_ns;
4721                         while ( count( $parts ) > 0 ) {
4722                                 $editnotice_base .= '-' . array_shift( $parts );
4723                                 $msg = wfMessage( $editnotice_base );
4724                                 if ( $msg->exists() ) {
4725                                         $html = $msg->parseAsBlock();
4726                                         if ( trim( $html ) !== '' ) {
4727                                                 $notices[$editnotice_base] = Html::rawElement(
4728                                                         'div',
4729                                                         array( 'class' => array(
4730                                                                 'mw-editnotice',
4731                                                                 'mw-editnotice-base',
4732                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4733                                                         ) ),
4734                                                         $html
4735                                                 );
4736                                         }
4737                                 }
4738                         }
4739                 } else {
4740                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4741                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4742                         $msg = wfMessage( $editnoticeText );
4743                         if ( $msg->exists() ) {
4744                                 $html = $msg->parseAsBlock();
4745                                 if ( trim( $html ) !== '' ) {
4746                                         $notices[$editnoticeText] = Html::rawElement(
4747                                                 'div',
4748                                                 array( 'class' => array(
4749                                                         'mw-editnotice',
4750                                                         'mw-editnotice-page',
4751                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4752                                                 ) ),
4753                                                 $html
4754                                         );
4755                                 }
4756                         }
4757                 }
4758
4759                 Hooks::run( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4760                 return $notices;
4761         }
4762
4763         /**
4764          * @return array
4765          */
4766         public function __sleep() {
4767                 return array(
4768                         'mNamespace',
4769                         'mDbkeyform',
4770                         'mFragment',
4771                         'mInterwiki',
4772                         'mLocalInterwiki',
4773                         'mUserCaseDBKey',
4774                         'mDefaultNamespace',
4775                 );
4776         }
4777
4778         public function __wakeup() {
4779                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4780                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4781                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4782         }
4783
4784 }