includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 /**
  26  * Represents a title within MediaWiki.
  27  * Optionally may contain an interwiki designation or namespace.
  28  * @note This class can fetch various kinds of data from the database;
  29  *       however, it does so inefficiently.
  30  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  31  *       and does not rely on global state or the database.
  32  *
  33  * @internal documentation reviewed 15 Mar 2010
  34  */
  35 class Title {
  36         /** @var MapCacheLRU */
  37         static private $titleCache = null;
  38
  39         /**
  40          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  41          * commonly used titles. On a batch operation this can become a memory leak
  42          * if not bounded. After hitting this many titles reset the cache.
  43          */
  44         const CACHE_MAX = 1000;
  45
  46         /**
  47          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  48          * to use the master DB
  49          */
  50         const GAID_FOR_UPDATE = 1;
  51
  52         /**
  53          * @name Private member variables
  54          * Please use the accessor functions instead.
  55          * @private
  56          */
  57         // @{
  58
  59         /** @var string Text form (spaces not underscores) of the main part */
  60         public $mTextform = '';
  61
  62         /** @var string URL-encoded form of the main part */
  63         public $mUrlform = '';
  64
  65         /** @var string Main part with underscores */
  66         public $mDbkeyform = '';
  67
  68         /** @var string Database key with the initial letter in the case specified by the user */
  69         protected $mUserCaseDBKey;
  70
  71         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  72         public $mNamespace = NS_MAIN;
  73
  74         /** @var string Interwiki prefix */
  75         public $mInterwiki = '';
  76
  77         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  78         private $mLocalInterwiki = false;
  79
  80         /** @var string Title fragment (i.e. the bit after the #) */
  81         public $mFragment = '';
  82
  83         /** @var int Article ID, fetched from the link cache on demand */
  84         public $mArticleID = -1;
  85
  86         /** @var bool|int ID of most recent revision */
  87         protected $mLatestID = false;
  88
  89         /**
  90          * @var bool|string ID of the page's content model, i.e. one of the
  91          *   CONTENT_MODEL_XXX constants
  92          */
  93         public $mContentModel = false;
  94
  95         /** @var int Estimated number of revisions; null of not loaded */
  96         private $mEstimateRevisions;
  97
  98         /** @var array Array of groups allowed to edit this article */
  99         public $mRestrictions = array();
 100
 101         /** @var bool */
 102         protected $mOldRestrictions = false;
 103
 104         /** @var bool Cascade restrictions on this page to included templates and images? */
 105         public $mCascadeRestriction;
 106
 107         /** Caching the results of getCascadeProtectionSources */
 108         public $mCascadingRestrictions;
 109
 110         /** @var array When do the restrictions on this page expire? */
 111         protected $mRestrictionsExpiry = array();
 112
 113         /** @var bool Are cascading restrictions in effect on this page? */
 114         protected $mHasCascadingRestrictions;
 115
 116         /** @var array Where are the cascading restrictions coming from on this page? */
 117         public $mCascadeSources;
 118
 119         /** @var bool Boolean for initialisation on demand */
 120         public $mRestrictionsLoaded = false;
 121
 122         /** @var string Text form including namespace/interwiki, initialised on demand */
 123         protected $mPrefixedText = null;
 124
 125         /** @var mixed Cached value for getTitleProtection (create protection) */
 126         public $mTitleProtection;
 127
 128         /**
 129          * @var int Namespace index when there is no namespace. Don't change the
 130          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 131          *   Zero except in {{transclusion}} tags.
 132          */
 133         public $mDefaultNamespace = NS_MAIN;
 134
 135         /**
 136          * @var bool Is $wgUser watching this page? null if unfilled, accessed
 137          * through userIsWatching()
 138          */
 139         protected $mWatched = null;
 140
 141         /** @var int The page length, 0 for special pages */
 142         protected $mLength = -1;
 143
 144         /** @var null Is the article at this title a redirect? */
 145         public $mRedirect = null;
 146
 147         /** @var array Associative array of user ID -> timestamp/false */
 148         private $mNotificationTimestamp = array();
 149
 150         /** @var bool Whether a page has any subpages */
 151         private $mHasSubpages;
 152
 153         /** @var bool The (string) language code of the page's language and content code. */
 154         private $mPageLanguage = false;
 155
 156         /** @var string The page language code from the database */
 157         private $mDbPageLanguage = null;
 158
 159         /** @var TitleValue A corresponding TitleValue object */
 160         private $mTitleValue = null;
 161         // @}
 162
 163         /**
 164          * B/C kludge: provide a TitleParser for use by Title.
 165          * Ideally, Title would have no methods that need this.
 166          * Avoid usage of this singleton by using TitleValue
 167          * and the associated services when possible.
 168          *
 169          * @return TitleParser
 170          */
 171         private static function getTitleParser() {
 172                 global $wgContLang, $wgLocalInterwikis;
 173
 174                 static $titleCodec = null;
 175                 static $titleCodecFingerprint = null;
 176
 177                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 178                 // make sure we are using the right one. To detect changes over the course
 179                 // of a request, we remember a fingerprint of the config used to create the
 180                 // codec singleton, and re-create it if the fingerprint doesn't match.
 181                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . join( '+', $wgLocalInterwikis );
 182
 183                 if ( $fingerprint !== $titleCodecFingerprint ) {
 184                         $titleCodec = null;
 185                 }
 186
 187                 if ( !$titleCodec ) {
 188                         $titleCodec = new MediaWikiTitleCodec(
 189                                 $wgContLang,
 190                                 GenderCache::singleton(),
 191                                 $wgLocalInterwikis
 192                         );
 193                         $titleCodecFingerprint = $fingerprint;
 194                 }
 195
 196                 return $titleCodec;
 197         }
 198
 199         /**
 200          * B/C kludge: provide a TitleParser for use by Title.
 201          * Ideally, Title would have no methods that need this.
 202          * Avoid usage of this singleton by using TitleValue
 203          * and the associated services when possible.
 204          *
 205          * @return TitleFormatter
 206          */
 207         private static function getTitleFormatter() {
 208                 //NOTE: we know that getTitleParser() returns a MediaWikiTitleCodec,
 209                 //      which implements TitleFormatter.
 210                 return self::getTitleParser();
 211         }
 212
 213         function __construct() {
 214         }
 215
 216         /**
 217          * Create a new Title from a prefixed DB key
 218          *
 219          * @param string $key The database key, which has underscores
 220          *      instead of spaces, possibly including namespace and
 221          *      interwiki prefixes
 222          * @return Title|null Title, or null on an error
 223          */
 224         public static function newFromDBkey( $key ) {
 225                 $t = new Title();
 226                 $t->mDbkeyform = $key;
 227                 if ( $t->secureAndSplit() ) {
 228                         return $t;
 229                 } else {
 230                         return null;
 231                 }
 232         }
 233
 234         /**
 235          * Create a new Title from a TitleValue
 236          *
 237          * @param TitleValue $titleValue Assumed to be safe.
 238          *
 239          * @return Title
 240          */
 241         public static function newFromTitleValue( TitleValue $titleValue ) {
 242                 return self::makeTitle(
 243                         $titleValue->getNamespace(),
 244                         $titleValue->getText(),
 245                         $titleValue->getFragment() );
 246         }
 247
 248         /**
 249          * Create a new Title from text, such as what one would find in a link. De-
 250          * codes any HTML entities in the text.
 251          *
 252          * @param string $text The link text; spaces, prefixes, and an
 253          *   initial ':' indicating the main namespace are accepted.
 254          * @param int $defaultNamespace The namespace to use if none is specified
 255          *   by a prefix.  If you want to force a specific namespace even if
 256          *   $text might begin with a namespace prefix, use makeTitle() or
 257          *   makeTitleSafe().
 258          * @throws MWException
 259          * @return Title|null Title or null on an error.
 260          */
 261         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 262                 if ( is_object( $text ) ) {
 263                         throw new MWException( 'Title::newFromText given an object' );
 264                 }
 265
 266                 $cache = self::getTitleCache();
 267
 268                 /**
 269                  * Wiki pages often contain multiple links to the same page.
 270                  * Title normalization and parsing can become expensive on
 271                  * pages with many links, so we can save a little time by
 272                  * caching them.
 273                  *
 274                  * In theory these are value objects and won't get changed...
 275                  */
 276                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 277                         return $cache->get( $text );
 278                 }
 279
 280                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 281                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 282
 283                 $t = new Title();
 284                 $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
 285                 $t->mDefaultNamespace = intval( $defaultNamespace );
 286
 287                 if ( $t->secureAndSplit() ) {
 288                         if ( $defaultNamespace == NS_MAIN ) {
 289                                 $cache->set( $text, $t );
 290                         }
 291                         return $t;
 292                 } else {
 293                         return null;
 294                 }
 295         }
 296
 297         /**
 298          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 299          *
 300          * Example of wrong and broken code:
 301          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 302          *
 303          * Example of right code:
 304          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 305          *
 306          * Create a new Title from URL-encoded text. Ensures that
 307          * the given title's length does not exceed the maximum.
 308          *
 309          * @param string $url The title, as might be taken from a URL
 310          * @return Title|null The new object, or null on an error
 311          */
 312         public static function newFromURL( $url ) {
 313                 $t = new Title();
 314
 315                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 316                 # but some URLs used it as a space replacement and they still come
 317                 # from some external search tools.
 318                 if ( strpos( self::legalChars(), '+' ) === false ) {
 319                         $url = str_replace( '+', ' ', $url );
 320                 }
 321
 322                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 323                 if ( $t->secureAndSplit() ) {
 324                         return $t;
 325                 } else {
 326                         return null;
 327                 }
 328         }
 329
 330         /**
 331          * @return MapCacheLRU
 332          */
 333         private static function getTitleCache() {
 334                 if ( self::$titleCache == null ) {
 335                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 336                 }
 337                 return self::$titleCache;
 338         }
 339
 340         /**
 341          * Returns a list of fields that are to be selected for initializing Title
 342          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 343          * whether to include page_content_model.
 344          *
 345          * @return array
 346          */
 347         protected static function getSelectFields() {
 348                 global $wgContentHandlerUseDB;
 349
 350                 $fields = array(
 351                         'page_namespace', 'page_title', 'page_id',
 352                         'page_len', 'page_is_redirect', 'page_latest',
 353                 );
 354
 355                 if ( $wgContentHandlerUseDB ) {
 356                         $fields[] = 'page_content_model';
 357                 }
 358
 359                 return $fields;
 360         }
 361
 362         /**
 363          * Create a new Title from an article ID
 364          *
 365          * @param int $id The page_id corresponding to the Title to create
 366          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 367          * @return Title|null The new object, or null on an error
 368          */
 369         public static function newFromID( $id, $flags = 0 ) {
 370                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 371                 $row = $db->selectRow(
 372                         'page',
 373                         self::getSelectFields(),
 374                         array( 'page_id' => $id ),
 375                         __METHOD__
 376                 );
 377                 if ( $row !== false ) {
 378                         $title = Title::newFromRow( $row );
 379                 } else {
 380                         $title = null;
 381                 }
 382                 return $title;
 383         }
 384
 385         /**
 386          * Make an array of titles from an array of IDs
 387          *
 388          * @param int[] $ids Array of IDs
 389          * @return Title[] Array of Titles
 390          */
 391         public static function newFromIDs( $ids ) {
 392                 if ( !count( $ids ) ) {
 393                         return array();
 394                 }
 395                 $dbr = wfGetDB( DB_SLAVE );
 396
 397                 $res = $dbr->select(
 398                         'page',
 399                         self::getSelectFields(),
 400                         array( 'page_id' => $ids ),
 401                         __METHOD__
 402                 );
 403
 404                 $titles = array();
 405                 foreach ( $res as $row ) {
 406                         $titles[] = Title::newFromRow( $row );
 407                 }
 408                 return $titles;
 409         }
 410
 411         /**
 412          * Make a Title object from a DB row
 413          *
 414          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 415          * @return Title Corresponding Title
 416          */
 417         public static function newFromRow( $row ) {
 418                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 419                 $t->loadFromRow( $row );
 420                 return $t;
 421         }
 422
 423         /**
 424          * Load Title object fields from a DB row.
 425          * If false is given, the title will be treated as non-existing.
 426          *
 427          * @param stdClass|bool $row Database row
 428          */
 429         public function loadFromRow( $row ) {
 430                 if ( $row ) { // page found
 431                         if ( isset( $row->page_id ) ) {
 432                                 $this->mArticleID = (int)$row->page_id;
 433                         }
 434                         if ( isset( $row->page_len ) ) {
 435                                 $this->mLength = (int)$row->page_len;
 436                         }
 437                         if ( isset( $row->page_is_redirect ) ) {
 438                                 $this->mRedirect = (bool)$row->page_is_redirect;
 439                         }
 440                         if ( isset( $row->page_latest ) ) {
 441                                 $this->mLatestID = (int)$row->page_latest;
 442                         }
 443                         if ( isset( $row->page_content_model ) ) {
 444                                 $this->mContentModel = strval( $row->page_content_model );
 445                         } else {
 446                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 447                         }
 448                         if ( isset( $row->page_lang ) ) {
 449                                 $this->mDbPageLanguage = (string)$row->page_lang;
 450                         }
 451                 } else { // page not found
 452                         $this->mArticleID = 0;
 453                         $this->mLength = 0;
 454                         $this->mRedirect = false;
 455                         $this->mLatestID = 0;
 456                         $this->mContentModel = false; # initialized lazily in getContentModel()
 457                 }
 458         }
 459
 460         /**
 461          * Create a new Title from a namespace index and a DB key.
 462          * It's assumed that $ns and $title are *valid*, for instance when
 463          * they came directly from the database or a special page name.
 464          * For convenience, spaces are converted to underscores so that
 465          * eg user_text fields can be used directly.
 466          *
 467          * @param int $ns The namespace of the article
 468          * @param string $title The unprefixed database key form
 469          * @param string $fragment The link fragment (after the "#")
 470          * @param string $interwiki The interwiki prefix
 471          * @return Title The new object
 472          */
 473         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 474                 $t = new Title();
 475                 $t->mInterwiki = $interwiki;
 476                 $t->mFragment = $fragment;
 477                 $t->mNamespace = $ns = intval( $ns );
 478                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 479                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 480                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 481                 $t->mTextform = str_replace( '_', ' ', $title );
 482                 $t->mContentModel = false; # initialized lazily in getContentModel()
 483                 return $t;
 484         }
 485
 486         /**
 487          * Create a new Title from a namespace index and a DB key.
 488          * The parameters will be checked for validity, which is a bit slower
 489          * than makeTitle() but safer for user-provided data.
 490          *
 491          * @param int $ns The namespace of the article
 492          * @param string $title Database key form
 493          * @param string $fragment The link fragment (after the "#")
 494          * @param string $interwiki Interwiki prefix
 495          * @return Title The new object, or null on an error
 496          */
 497         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 498                 if ( !MWNamespace::exists( $ns ) ) {
 499                         return null;
 500                 }
 501
 502                 $t = new Title();
 503                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 504                 if ( $t->secureAndSplit() ) {
 505                         return $t;
 506                 } else {
 507                         return null;
 508                 }
 509         }
 510
 511         /**
 512          * Create a new Title for the Main Page
 513          *
 514          * @return Title The new object
 515          */
 516         public static function newMainPage() {
 517                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 518                 // Don't give fatal errors if the message is broken
 519                 if ( !$title ) {
 520                         $title = Title::newFromText( 'Main Page' );
 521                 }
 522                 return $title;
 523         }
 524
 525         /**
 526          * Extract a redirect destination from a string and return the
 527          * Title, or null if the text doesn't contain a valid redirect
 528          * This will only return the very next target, useful for
 529          * the redirect table and other checks that don't need full recursion
 530          *
 531          * @param string $text Text with possible redirect
 532          * @return Title The corresponding Title
 533          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 534          */
 535         public static function newFromRedirect( $text ) {
 536                 ContentHandler::deprecated( __METHOD__, '1.21' );
 537
 538                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 539                 return $content->getRedirectTarget();
 540         }
 541
 542         /**
 543          * Extract a redirect destination from a string and return the
 544          * Title, or null if the text doesn't contain a valid redirect
 545          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 546          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 547          *
 548          * @param string $text Text with possible redirect
 549          * @return Title
 550          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 551          */
 552         public static function newFromRedirectRecurse( $text ) {
 553                 ContentHandler::deprecated( __METHOD__, '1.21' );
 554
 555                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 556                 return $content->getUltimateRedirectTarget();
 557         }
 558
 559         /**
 560          * Extract a redirect destination from a string and return an
 561          * array of Titles, or null if the text doesn't contain a valid redirect
 562          * The last element in the array is the final destination after all redirects
 563          * have been resolved (up to $wgMaxRedirects times)
 564          *
 565          * @param string $text Text with possible redirect
 566          * @return Title[] Array of Titles, with the destination last
 567          * @deprecated since 1.21, use Content::getRedirectChain instead.
 568          */
 569         public static function newFromRedirectArray( $text ) {
 570                 ContentHandler::deprecated( __METHOD__, '1.21' );
 571
 572                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 573                 return $content->getRedirectChain();
 574         }
 575
 576         /**
 577          * Get the prefixed DB key associated with an ID
 578          *
 579          * @param int $id The page_id of the article
 580          * @return Title|null An object representing the article, or null if no such article was found
 581          */
 582         public static function nameOf( $id ) {
 583                 $dbr = wfGetDB( DB_SLAVE );
 584
 585                 $s = $dbr->selectRow(
 586                         'page',
 587                         array( 'page_namespace', 'page_title' ),
 588                         array( 'page_id' => $id ),
 589                         __METHOD__
 590                 );
 591                 if ( $s === false ) {
 592                         return null;
 593                 }
 594
 595                 $n = self::makeName( $s->page_namespace, $s->page_title );
 596                 return $n;
 597         }
 598
 599         /**
 600          * Get a regex character class describing the legal characters in a link
 601          *
 602          * @return string The list of characters, not delimited
 603          */
 604         public static function legalChars() {
 605                 global $wgLegalTitleChars;
 606                 return $wgLegalTitleChars;
 607         }
 608
 609         /**
 610          * Returns a simple regex that will match on characters and sequences invalid in titles.
 611          * Note that this doesn't pick up many things that could be wrong with titles, but that
 612          * replacing this regex with something valid will make many titles valid.
 613          *
 614          * @todo move this into MediaWikiTitleCodec
 615          *
 616          * @return string Regex string
 617          */
 618         static function getTitleInvalidRegex() {
 619                 static $rxTc = false;
 620                 if ( !$rxTc ) {
 621                         # Matching titles will be held as illegal.
 622                         $rxTc = '/' .
 623                                 # Any character not allowed is forbidden...
 624                                 '[^' . self::legalChars() . ']' .
 625                                 # URL percent encoding sequences interfere with the ability
 626                                 # to round-trip titles -- you can't link to them consistently.
 627                                 '|%[0-9A-Fa-f]{2}' .
 628                                 # XML/HTML character references produce similar issues.
 629                                 '|&[A-Za-z0-9\x80-\xff]+;' .
 630                                 '|&#[0-9]+;' .
 631                                 '|&#x[0-9A-Fa-f]+;' .
 632                                 '/S';
 633                 }
 634
 635                 return $rxTc;
 636         }
 637
 638         /**
 639          * Utility method for converting a character sequence from bytes to Unicode.
 640          *
 641          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 642          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 643          *
 644          * @param string $byteClass
 645          * @return string
 646          */
 647         public static function convertByteClassToUnicodeClass( $byteClass ) {
 648                 $length = strlen( $byteClass );
 649                 // Input token queue
 650                 $x0 = $x1 = $x2 = '';
 651                 // Decoded queue
 652                 $d0 = $d1 = $d2 = '';
 653                 // Decoded integer codepoints
 654                 $ord0 = $ord1 = $ord2 = 0;
 655                 // Re-encoded queue
 656                 $r0 = $r1 = $r2 = '';
 657                 // Output
 658                 $out = '';
 659                 // Flags
 660                 $allowUnicode = false;
 661                 for ( $pos = 0; $pos < $length; $pos++ ) {
 662                         // Shift the queues down
 663                         $x2 = $x1;
 664                         $x1 = $x0;
 665                         $d2 = $d1;
 666                         $d1 = $d0;
 667                         $ord2 = $ord1;
 668                         $ord1 = $ord0;
 669                         $r2 = $r1;
 670                         $r1 = $r0;
 671                         // Load the current input token and decoded values
 672                         $inChar = $byteClass[$pos];
 673                         if ( $inChar == '\\' ) {
 674                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 675                                         $x0 = $inChar . $m[0];
 676                                         $d0 = chr( hexdec( $m[1] ) );
 677                                         $pos += strlen( $m[0] );
 678                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 679                                         $x0 = $inChar . $m[0];
 680                                         $d0 = chr( octdec( $m[0] ) );
 681                                         $pos += strlen( $m[0] );
 682                                 } elseif ( $pos + 1 >= $length ) {
 683                                         $x0 = $d0 = '\\';
 684                                 } else {
 685                                         $d0 = $byteClass[$pos + 1];
 686                                         $x0 = $inChar . $d0;
 687                                         $pos += 1;
 688                                 }
 689                         } else {
 690                                 $x0 = $d0 = $inChar;
 691                         }
 692                         $ord0 = ord( $d0 );
 693                         // Load the current re-encoded value
 694                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 695                                 $r0 = sprintf( '\x%02x', $ord0 );
 696                         } elseif ( $ord0 >= 0x80 ) {
 697                                 // Allow unicode if a single high-bit character appears
 698                                 $r0 = sprintf( '\x%02x', $ord0 );
 699                                 $allowUnicode = true;
 700                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 701                                 $r0 = '\\' . $d0;
 702                         } else {
 703                                 $r0 = $d0;
 704                         }
 705                         // Do the output
 706                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 707                                 // Range
 708                                 if ( $ord2 > $ord0 ) {
 709                                         // Empty range
 710                                 } elseif ( $ord0 >= 0x80 ) {
 711                                         // Unicode range
 712                                         $allowUnicode = true;
 713                                         if ( $ord2 < 0x80 ) {
 714                                                 // Keep the non-unicode section of the range
 715                                                 $out .= "$r2-\\x7F";
 716                                         }
 717                                 } else {
 718                                         // Normal range
 719                                         $out .= "$r2-$r0";
 720                                 }
 721                                 // Reset state to the initial value
 722                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 723                         } elseif ( $ord2 < 0x80 ) {
 724                                 // ASCII character
 725                                 $out .= $r2;
 726                         }
 727                 }
 728                 if ( $ord1 < 0x80 ) {
 729                         $out .= $r1;
 730                 }
 731                 if ( $ord0 < 0x80 ) {
 732                         $out .= $r0;
 733                 }
 734                 if ( $allowUnicode ) {
 735                         $out .= '\u0080-\uFFFF';
 736                 }
 737                 return $out;
 738         }
 739
 740         /**
 741          * Make a prefixed DB key from a DB key and a namespace index
 742          *
 743          * @param int $ns Numerical representation of the namespace
 744          * @param string $title The DB key form the title
 745          * @param string $fragment The link fragment (after the "#")
 746          * @param string $interwiki The interwiki prefix
 747          * @return string The prefixed form of the title
 748          */
 749         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 750                 global $wgContLang;
 751
 752                 $namespace = $wgContLang->getNsText( $ns );
 753                 $name = $namespace == '' ? $title : "$namespace:$title";
 754                 if ( strval( $interwiki ) != '' ) {
 755                         $name = "$interwiki:$name";
 756                 }
 757                 if ( strval( $fragment ) != '' ) {
 758                         $name .= '#' . $fragment;
 759                 }
 760                 return $name;
 761         }
 762
 763         /**
 764          * Escape a text fragment, say from a link, for a URL
 765          *
 766          * @param string $fragment Containing a URL or link fragment (after the "#")
 767          * @return string Escaped string
 768          */
 769         static function escapeFragmentForURL( $fragment ) {
 770                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 771                 # fragments appear not to work in IE (at least up to 7) or in at least
 772                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 773                 # to care if they aren't encoded.
 774                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 775         }
 776
 777         /**
 778          * Callback for usort() to do title sorts by (namespace, title)
 779          *
 780          * @param Title $a
 781          * @param Title $b
 782          *
 783          * @return int Result of string comparison, or namespace comparison
 784          */
 785         public static function compare( $a, $b ) {
 786                 if ( $a->getNamespace() == $b->getNamespace() ) {
 787                         return strcmp( $a->getText(), $b->getText() );
 788                 } else {
 789                         return $a->getNamespace() - $b->getNamespace();
 790                 }
 791         }
 792
 793         /**
 794          * Determine whether the object refers to a page within
 795          * this project.
 796          *
 797          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 798          */
 799         public function isLocal() {
 800                 if ( $this->isExternal() ) {
 801                         $iw = Interwiki::fetch( $this->mInterwiki );
 802                         if ( $iw ) {
 803                                 return $iw->isLocal();
 804                         }
 805                 }
 806                 return true;
 807         }
 808
 809         /**
 810          * Is this Title interwiki?
 811          *
 812          * @return bool
 813          */
 814         public function isExternal() {
 815                 return $this->mInterwiki !== '';
 816         }
 817
 818         /**
 819          * Get the interwiki prefix
 820          *
 821          * Use Title::isExternal to check if a interwiki is set
 822          *
 823          * @return string Interwiki prefix
 824          */
 825         public function getInterwiki() {
 826                 return $this->mInterwiki;
 827         }
 828
 829         /**
 830          * Was this a local interwiki link?
 831          *
 832          * @return bool
 833          */
 834         public function wasLocalInterwiki() {
 835                 return $this->mLocalInterwiki;
 836         }
 837
 838         /**
 839          * Determine whether the object refers to a page within
 840          * this project and is transcludable.
 841          *
 842          * @return bool True if this is transcludable
 843          */
 844         public function isTrans() {
 845                 if ( !$this->isExternal() ) {
 846                         return false;
 847                 }
 848
 849                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 850         }
 851
 852         /**
 853          * Returns the DB name of the distant wiki which owns the object.
 854          *
 855          * @return string The DB name
 856          */
 857         public function getTransWikiID() {
 858                 if ( !$this->isExternal() ) {
 859                         return false;
 860                 }
 861
 862                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 863         }
 864
 865         /**
 866          * Get a TitleValue object representing this Title.
 867          *
 868          * @note Not all valid Titles have a corresponding valid TitleValue
 869          * (e.g. TitleValues cannot represent page-local links that have a
 870          * fragment but no title text).
 871          *
 872          * @return TitleValue|null
 873          */
 874         public function getTitleValue() {
 875                 if ( $this->mTitleValue === null ) {
 876                         try {
 877                                 $this->mTitleValue = new TitleValue(
 878                                         $this->getNamespace(),
 879                                         $this->getDBkey(),
 880                                         $this->getFragment() );
 881                         } catch ( InvalidArgumentException $ex ) {
 882                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 883                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 884                         }
 885                 }
 886
 887                 return $this->mTitleValue;
 888         }
 889
 890         /**
 891          * Get the text form (spaces not underscores) of the main part
 892          *
 893          * @return string Main part of the title
 894          */
 895         public function getText() {
 896                 return $this->mTextform;
 897         }
 898
 899         /**
 900          * Get the URL-encoded form of the main part
 901          *
 902          * @return string Main part of the title, URL-encoded
 903          */
 904         public function getPartialURL() {
 905                 return $this->mUrlform;
 906         }
 907
 908         /**
 909          * Get the main part with underscores
 910          *
 911          * @return string Main part of the title, with underscores
 912          */
 913         public function getDBkey() {
 914                 return $this->mDbkeyform;
 915         }
 916
 917         /**
 918          * Get the DB key with the initial letter case as specified by the user
 919          *
 920          * @return string DB key
 921          */
 922         function getUserCaseDBKey() {
 923                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 924                         return $this->mUserCaseDBKey;
 925                 } else {
 926                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 927                         return $this->mDbkeyform;
 928                 }
 929         }
 930
 931         /**
 932          * Get the namespace index, i.e. one of the NS_xxxx constants.
 933          *
 934          * @return int Namespace index
 935          */
 936         public function getNamespace() {
 937                 return $this->mNamespace;
 938         }
 939
 940         /**
 941          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 942          *
 943          * @throws MWException
 944          * @return string Content model id
 945          */
 946         public function getContentModel() {
 947                 if ( !$this->mContentModel ) {
 948                         $linkCache = LinkCache::singleton();
 949                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 950                 }
 951
 952                 if ( !$this->mContentModel ) {
 953                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 954                 }
 955
 956                 if ( !$this->mContentModel ) {
 957                         throw new MWException( 'Failed to determine content model!' );
 958                 }
 959
 960                 return $this->mContentModel;
 961         }
 962
 963         /**
 964          * Convenience method for checking a title's content model name
 965          *
 966          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 967          * @return bool True if $this->getContentModel() == $id
 968          */
 969         public function hasContentModel( $id ) {
 970                 return $this->getContentModel() == $id;
 971         }
 972
 973         /**
 974          * Get the namespace text
 975          *
 976          * @return string Namespace text
 977          */
 978         public function getNsText() {
 979                 if ( $this->isExternal() ) {
 980                         // This probably shouldn't even happen. ohh man, oh yuck.
 981                         // But for interwiki transclusion it sometimes does.
 982                         // Shit. Shit shit shit.
 983                         //
 984                         // Use the canonical namespaces if possible to try to
 985                         // resolve a foreign namespace.
 986                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 987                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 988                         }
 989                 }
 990
 991                 try {
 992                         $formatter = self::getTitleFormatter();
 993                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 994                 } catch ( InvalidArgumentException $ex ) {
 995                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 996                         return false;
 997                 }
 998         }
 999
1000         /**
1001          * Get the namespace text of the subject (rather than talk) page
1002          *
1003          * @return string Namespace text
1004          */
1005         public function getSubjectNsText() {
1006                 global $wgContLang;
1007                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1008         }
1009
1010         /**
1011          * Get the namespace text of the talk page
1012          *
1013          * @return string Namespace text
1014          */
1015         public function getTalkNsText() {
1016                 global $wgContLang;
1017                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1018         }
1019
1020         /**
1021          * Could this title have a corresponding talk page?
1022          *
1023          * @return bool
1024          */
1025         public function canTalk() {
1026                 return MWNamespace::canTalk( $this->mNamespace );
1027         }
1028
1029         /**
1030          * Is this in a namespace that allows actual pages?
1031          *
1032          * @return bool
1033          * @internal note -- uses hardcoded namespace index instead of constants
1034          */
1035         public function canExist() {
1036                 return $this->mNamespace >= NS_MAIN;
1037         }
1038
1039         /**
1040          * Can this title be added to a user's watchlist?
1041          *
1042          * @return bool
1043          */
1044         public function isWatchable() {
1045                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1046         }
1047
1048         /**
1049          * Returns true if this is a special page.
1050          *
1051          * @return bool
1052          */
1053         public function isSpecialPage() {
1054                 return $this->getNamespace() == NS_SPECIAL;
1055         }
1056
1057         /**
1058          * Returns true if this title resolves to the named special page
1059          *
1060          * @param string $name The special page name
1061          * @return bool
1062          */
1063         public function isSpecial( $name ) {
1064                 if ( $this->isSpecialPage() ) {
1065                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1066                         if ( $name == $thisName ) {
1067                                 return true;
1068                         }
1069                 }
1070                 return false;
1071         }
1072
1073         /**
1074          * If the Title refers to a special page alias which is not the local default, resolve
1075          * the alias, and localise the name as necessary.  Otherwise, return $this
1076          *
1077          * @return Title
1078          */
1079         public function fixSpecialName() {
1080                 if ( $this->isSpecialPage() ) {
1081                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1082                         if ( $canonicalName ) {
1083                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1084                                 if ( $localName != $this->mDbkeyform ) {
1085                                         return Title::makeTitle( NS_SPECIAL, $localName );
1086                                 }
1087                         }
1088                 }
1089                 return $this;
1090         }
1091
1092         /**
1093          * Returns true if the title is inside the specified namespace.
1094          *
1095          * Please make use of this instead of comparing to getNamespace()
1096          * This function is much more resistant to changes we may make
1097          * to namespaces than code that makes direct comparisons.
1098          * @param int $ns The namespace
1099          * @return bool
1100          * @since 1.19
1101          */
1102         public function inNamespace( $ns ) {
1103                 return MWNamespace::equals( $this->getNamespace(), $ns );
1104         }
1105
1106         /**
1107          * Returns true if the title is inside one of the specified namespaces.
1108          *
1109          * @param int $namespaces,... The namespaces to check for
1110          * @return bool
1111          * @since 1.19
1112          */
1113         public function inNamespaces( /* ... */ ) {
1114                 $namespaces = func_get_args();
1115                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1116                         $namespaces = $namespaces[0];
1117                 }
1118
1119                 foreach ( $namespaces as $ns ) {
1120                         if ( $this->inNamespace( $ns ) ) {
1121                                 return true;
1122                         }
1123                 }
1124
1125                 return false;
1126         }
1127
1128         /**
1129          * Returns true if the title has the same subject namespace as the
1130          * namespace specified.
1131          * For example this method will take NS_USER and return true if namespace
1132          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1133          * as their subject namespace.
1134          *
1135          * This is MUCH simpler than individually testing for equivalence
1136          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1137          * @since 1.19
1138          * @param int $ns
1139          * @return bool
1140          */
1141         public function hasSubjectNamespace( $ns ) {
1142                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1143         }
1144
1145         /**
1146          * Is this Title in a namespace which contains content?
1147          * In other words, is this a content page, for the purposes of calculating
1148          * statistics, etc?
1149          *
1150          * @return bool
1151          */
1152         public function isContentPage() {
1153                 return MWNamespace::isContent( $this->getNamespace() );
1154         }
1155
1156         /**
1157          * Would anybody with sufficient privileges be able to move this page?
1158          * Some pages just aren't movable.
1159          *
1160          * @return bool
1161          */
1162         public function isMovable() {
1163                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1164                         // Interwiki title or immovable namespace. Hooks don't get to override here
1165                         return false;
1166                 }
1167
1168                 $result = true;
1169                 wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
1170                 return $result;
1171         }
1172
1173         /**
1174          * Is this the mainpage?
1175          * @note Title::newFromText seems to be sufficiently optimized by the title
1176          * cache that we don't need to over-optimize by doing direct comparisons and
1177          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1178          * ends up reporting something differently than $title->isMainPage();
1179          *
1180          * @since 1.18
1181          * @return bool
1182          */
1183         public function isMainPage() {
1184                 return $this->equals( Title::newMainPage() );
1185         }
1186
1187         /**
1188          * Is this a subpage?
1189          *
1190          * @return bool
1191          */
1192         public function isSubpage() {
1193                 return MWNamespace::hasSubpages( $this->mNamespace )
1194                         ? strpos( $this->getText(), '/' ) !== false
1195                         : false;
1196         }
1197
1198         /**
1199          * Is this a conversion table for the LanguageConverter?
1200          *
1201          * @return bool
1202          */
1203         public function isConversionTable() {
1204                 // @todo ConversionTable should become a separate content model.
1205
1206                 return $this->getNamespace() == NS_MEDIAWIKI &&
1207                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1208         }
1209
1210         /**
1211          * Does that page contain wikitext, or it is JS, CSS or whatever?
1212          *
1213          * @return bool
1214          */
1215         public function isWikitextPage() {
1216                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1217         }
1218
1219         /**
1220          * Could this page contain custom CSS or JavaScript for the global UI.
1221          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1222          * or CONTENT_MODEL_JAVASCRIPT.
1223          *
1224          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1225          * for that!
1226          *
1227          * Note that this method should not return true for pages that contain and
1228          * show "inactive" CSS or JS.
1229          *
1230          * @return bool
1231          */
1232         public function isCssOrJsPage() {
1233                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1234                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1235                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1236
1237                 # @note This hook is also called in ContentHandler::getDefaultModel.
1238                 #   It's called here again to make sure hook functions can force this
1239                 #   method to return true even outside the mediawiki namespace.
1240
1241                 wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ) );
1242
1243                 return $isCssOrJsPage;
1244         }
1245
1246         /**
1247          * Is this a .css or .js subpage of a user page?
1248          * @return bool
1249          */
1250         public function isCssJsSubpage() {
1251                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1252                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1253                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1254         }
1255
1256         /**
1257          * Trim down a .css or .js subpage title to get the corresponding skin name
1258          *
1259          * @return string Containing skin name from .css or .js subpage title
1260          */
1261         public function getSkinFromCssJsSubpage() {
1262                 $subpage = explode( '/', $this->mTextform );
1263                 $subpage = $subpage[count( $subpage ) - 1];
1264                 $lastdot = strrpos( $subpage, '.' );
1265                 if ( $lastdot === false ) {
1266                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1267                 }
1268                 return substr( $subpage, 0, $lastdot );
1269         }
1270
1271         /**
1272          * Is this a .css subpage of a user page?
1273          *
1274          * @return bool
1275          */
1276         public function isCssSubpage() {
1277                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1278                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1279         }
1280
1281         /**
1282          * Is this a .js subpage of a user page?
1283          *
1284          * @return bool
1285          */
1286         public function isJsSubpage() {
1287                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1288                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1289         }
1290
1291         /**
1292          * Is this a talk page of some sort?
1293          *
1294          * @return bool
1295          */
1296         public function isTalkPage() {
1297                 return MWNamespace::isTalk( $this->getNamespace() );
1298         }
1299
1300         /**
1301          * Get a Title object associated with the talk page of this article
1302          *
1303          * @return Title The object for the talk page
1304          */
1305         public function getTalkPage() {
1306                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1307         }
1308
1309         /**
1310          * Get a title object associated with the subject page of this
1311          * talk page
1312          *
1313          * @return Title The object for the subject page
1314          */
1315         public function getSubjectPage() {
1316                 // Is this the same title?
1317                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1318                 if ( $this->getNamespace() == $subjectNS ) {
1319                         return $this;
1320                 }
1321                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1322         }
1323
1324         /**
1325          * Get the default namespace index, for when there is no namespace
1326          *
1327          * @return int Default namespace index
1328          */
1329         public function getDefaultNamespace() {
1330                 return $this->mDefaultNamespace;
1331         }
1332
1333         /**
1334          * Get the Title fragment (i.e.\ the bit after the #) in text form
1335          *
1336          * Use Title::hasFragment to check for a fragment
1337          *
1338          * @return string Title fragment
1339          */
1340         public function getFragment() {
1341                 return $this->mFragment;
1342         }
1343
1344         /**
1345          * Check if a Title fragment is set
1346          *
1347          * @return bool
1348          * @since 1.23
1349          */
1350         public function hasFragment() {
1351                 return $this->mFragment !== '';
1352         }
1353
1354         /**
1355          * Get the fragment in URL form, including the "#" character if there is one
1356          * @return string Fragment in URL form
1357          */
1358         public function getFragmentForURL() {
1359                 if ( !$this->hasFragment() ) {
1360                         return '';
1361                 } else {
1362                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1363                 }
1364         }
1365
1366         /**
1367          * Set the fragment for this title. Removes the first character from the
1368          * specified fragment before setting, so it assumes you're passing it with
1369          * an initial "#".
1370          *
1371          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1372          * Still in active use privately.
1373          *
1374          * @param string $fragment Text
1375          */
1376         public function setFragment( $fragment ) {
1377                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1378         }
1379
1380         /**
1381          * Prefix some arbitrary text with the namespace or interwiki prefix
1382          * of this object
1383          *
1384          * @param string $name The text
1385          * @return string The prefixed text
1386          */
1387         private function prefix( $name ) {
1388                 $p = '';
1389                 if ( $this->isExternal() ) {
1390                         $p = $this->mInterwiki . ':';
1391                 }
1392
1393                 if ( 0 != $this->mNamespace ) {
1394                         $p .= $this->getNsText() . ':';
1395                 }
1396                 return $p . $name;
1397         }
1398
1399         /**
1400          * Get the prefixed database key form
1401          *
1402          * @return string The prefixed title, with underscores and
1403          *  any interwiki and namespace prefixes
1404          */
1405         public function getPrefixedDBkey() {
1406                 $s = $this->prefix( $this->mDbkeyform );
1407                 $s = str_replace( ' ', '_', $s );
1408                 return $s;
1409         }
1410
1411         /**
1412          * Get the prefixed title with spaces.
1413          * This is the form usually used for display
1414          *
1415          * @return string The prefixed title, with spaces
1416          */
1417         public function getPrefixedText() {
1418                 if ( $this->mPrefixedText === null ) {
1419                         $s = $this->prefix( $this->mTextform );
1420                         $s = str_replace( '_', ' ', $s );
1421                         $this->mPrefixedText = $s;
1422                 }
1423                 return $this->mPrefixedText;
1424         }
1425
1426         /**
1427          * Return a string representation of this title
1428          *
1429          * @return string Representation of this title
1430          */
1431         public function __toString() {
1432                 return $this->getPrefixedText();
1433         }
1434
1435         /**
1436          * Get the prefixed title with spaces, plus any fragment
1437          * (part beginning with '#')
1438          *
1439          * @return string The prefixed title, with spaces and the fragment, including '#'
1440          */
1441         public function getFullText() {
1442                 $text = $this->getPrefixedText();
1443                 if ( $this->hasFragment() ) {
1444                         $text .= '#' . $this->getFragment();
1445                 }
1446                 return $text;
1447         }
1448
1449         /**
1450          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1451          *
1452          * @par Example:
1453          * @code
1454          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1455          * # returns: 'Foo'
1456          * @endcode
1457          *
1458          * @return string Root name
1459          * @since 1.20
1460          */
1461         public function getRootText() {
1462                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1463                         return $this->getText();
1464                 }
1465
1466                 return strtok( $this->getText(), '/' );
1467         }
1468
1469         /**
1470          * Get the root page name title, i.e. the leftmost part before any slashes
1471          *
1472          * @par Example:
1473          * @code
1474          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1475          * # returns: Title{User:Foo}
1476          * @endcode
1477          *
1478          * @return Title Root title
1479          * @since 1.20
1480          */
1481         public function getRootTitle() {
1482                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1483         }
1484
1485         /**
1486          * Get the base page name without a namespace, i.e. the part before the subpage name
1487          *
1488          * @par Example:
1489          * @code
1490          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1491          * # returns: 'Foo/Bar'
1492          * @endcode
1493          *
1494          * @return string Base name
1495          */
1496         public function getBaseText() {
1497                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1498                         return $this->getText();
1499                 }
1500
1501                 $parts = explode( '/', $this->getText() );
1502                 # Don't discard the real title if there's no subpage involved
1503                 if ( count( $parts ) > 1 ) {
1504                         unset( $parts[count( $parts ) - 1] );
1505                 }
1506                 return implode( '/', $parts );
1507         }
1508
1509         /**
1510          * Get the base page name title, i.e. the part before the subpage name
1511          *
1512          * @par Example:
1513          * @code
1514          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1515          * # returns: Title{User:Foo/Bar}
1516          * @endcode
1517          *
1518          * @return Title Base title
1519          * @since 1.20
1520          */
1521         public function getBaseTitle() {
1522                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1523         }
1524
1525         /**
1526          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1527          *
1528          * @par Example:
1529          * @code
1530          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1531          * # returns: "Baz"
1532          * @endcode
1533          *
1534          * @return string Subpage name
1535          */
1536         public function getSubpageText() {
1537                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1538                         return $this->mTextform;
1539                 }
1540                 $parts = explode( '/', $this->mTextform );
1541                 return $parts[count( $parts ) - 1];
1542         }
1543
1544         /**
1545          * Get the title for a subpage of the current page
1546          *
1547          * @par Example:
1548          * @code
1549          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1550          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1551          * @endcode
1552          *
1553          * @param string $text The subpage name to add to the title
1554          * @return Title Subpage title
1555          * @since 1.20
1556          */
1557         public function getSubpage( $text ) {
1558                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1559         }
1560
1561         /**
1562          * Get a URL-encoded form of the subpage text
1563          *
1564          * @return string URL-encoded subpage name
1565          */
1566         public function getSubpageUrlForm() {
1567                 $text = $this->getSubpageText();
1568                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1569                 return $text;
1570         }
1571
1572         /**
1573          * Get a URL-encoded title (not an actual URL) including interwiki
1574          *
1575          * @return string The URL-encoded form
1576          */
1577         public function getPrefixedURL() {
1578                 $s = $this->prefix( $this->mDbkeyform );
1579                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1580                 return $s;
1581         }
1582
1583         /**
1584          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1585          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1586          * second argument named variant. This was deprecated in favor
1587          * of passing an array of option with a "variant" key
1588          * Once $query2 is removed for good, this helper can be dropped
1589          * and the wfArrayToCgi moved to getLocalURL();
1590          *
1591          * @since 1.19 (r105919)
1592          * @param array|string $query
1593          * @param bool $query2
1594          * @return string
1595          */
1596         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1597                 if ( $query2 !== false ) {
1598                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1599                                 "method called with a second parameter is deprecated. Add your " .
1600                                 "parameter to an array passed as the first parameter.", "1.19" );
1601                 }
1602                 if ( is_array( $query ) ) {
1603                         $query = wfArrayToCgi( $query );
1604                 }
1605                 if ( $query2 ) {
1606                         if ( is_string( $query2 ) ) {
1607                                 // $query2 is a string, we will consider this to be
1608                                 // a deprecated $variant argument and add it to the query
1609                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1610                         } else {
1611                                 $query2 = wfArrayToCgi( $query2 );
1612                         }
1613                         // If we have $query content add a & to it first
1614                         if ( $query ) {
1615                                 $query .= '&';
1616                         }
1617                         // Now append the queries together
1618                         $query .= $query2;
1619                 }
1620                 return $query;
1621         }
1622
1623         /**
1624          * Get a real URL referring to this title, with interwiki link and
1625          * fragment
1626          *
1627          * @see self::getLocalURL for the arguments.
1628          * @see wfExpandUrl
1629          * @param array|string $query
1630          * @param bool $query2
1631          * @param string $proto Protocol type to use in URL
1632          * @return string The URL
1633          */
1634         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1635                 $query = self::fixUrlQueryArgs( $query, $query2 );
1636
1637                 # Hand off all the decisions on urls to getLocalURL
1638                 $url = $this->getLocalURL( $query );
1639
1640                 # Expand the url to make it a full url. Note that getLocalURL has the
1641                 # potential to output full urls for a variety of reasons, so we use
1642                 # wfExpandUrl instead of simply prepending $wgServer
1643                 $url = wfExpandUrl( $url, $proto );
1644
1645                 # Finally, add the fragment.
1646                 $url .= $this->getFragmentForURL();
1647
1648                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1649                 return $url;
1650         }
1651
1652         /**
1653          * Get a URL with no fragment or server name (relative URL) from a Title object.
1654          * If this page is generated with action=render, however,
1655          * $wgServer is prepended to make an absolute URL.
1656          *
1657          * @see self::getFullURL to always get an absolute URL.
1658          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1659          *  valid to link, locally, to the current Title.
1660          * @see self::newFromText to produce a Title object.
1661          *
1662          * @param string|array $query An optional query string,
1663          *   not used for interwiki links. Can be specified as an associative array as well,
1664          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1665          *   Some query patterns will trigger various shorturl path replacements.
1666          * @param array $query2 An optional secondary query array. This one MUST
1667          *   be an array. If a string is passed it will be interpreted as a deprecated
1668          *   variant argument and urlencoded into a variant= argument.
1669          *   This second query argument will be added to the $query
1670          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1671          *   pair in the first parameter array instead.
1672          *
1673          * @return string String of the URL.
1674          */
1675         public function getLocalURL( $query = '', $query2 = false ) {
1676                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1677
1678                 $query = self::fixUrlQueryArgs( $query, $query2 );
1679
1680                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1681                 if ( $interwiki ) {
1682                         $namespace = $this->getNsText();
1683                         if ( $namespace != '' ) {
1684                                 # Can this actually happen? Interwikis shouldn't be parsed.
1685                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1686                                 $namespace .= ':';
1687                         }
1688                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1689                         $url = wfAppendQuery( $url, $query );
1690                 } else {
1691                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1692                         if ( $query == '' ) {
1693                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1694                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1695                         } else {
1696                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1697                                 $url = false;
1698                                 $matches = array();
1699
1700                                 if ( !empty( $wgActionPaths )
1701                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1702                                 ) {
1703                                         $action = urldecode( $matches[2] );
1704                                         if ( isset( $wgActionPaths[$action] ) ) {
1705                                                 $query = $matches[1];
1706                                                 if ( isset( $matches[4] ) ) {
1707                                                         $query .= $matches[4];
1708                                                 }
1709                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1710                                                 if ( $query != '' ) {
1711                                                         $url = wfAppendQuery( $url, $query );
1712                                                 }
1713                                         }
1714                                 }
1715
1716                                 if ( $url === false
1717                                         && $wgVariantArticlePath
1718                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1719                                         && $this->getPageLanguage()->hasVariants()
1720                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1721                                 ) {
1722                                         $variant = urldecode( $matches[1] );
1723                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1724                                                 // Only do the variant replacement if the given variant is a valid
1725                                                 // variant for the page's language.
1726                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1727                                                 $url = str_replace( '$1', $dbkey, $url );
1728                                         }
1729                                 }
1730
1731                                 if ( $url === false ) {
1732                                         if ( $query == '-' ) {
1733                                                 $query = '';
1734                                         }
1735                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1736                                 }
1737                         }
1738
1739                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1740
1741                         // @todo FIXME: This causes breakage in various places when we
1742                         // actually expected a local URL and end up with dupe prefixes.
1743                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1744                                 $url = $wgServer . $url;
1745                         }
1746                 }
1747                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1748                 return $url;
1749         }
1750
1751         /**
1752          * Get a URL that's the simplest URL that will be valid to link, locally,
1753          * to the current Title.  It includes the fragment, but does not include
1754          * the server unless action=render is used (or the link is external).  If
1755          * there's a fragment but the prefixed text is empty, we just return a link
1756          * to the fragment.
1757          *
1758          * The result obviously should not be URL-escaped, but does need to be
1759          * HTML-escaped if it's being output in HTML.
1760          *
1761          * @param array $query
1762          * @param bool $query2
1763          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1764          * @see self::getLocalURL for the arguments.
1765          * @return string The URL
1766          */
1767         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1768                 wfProfileIn( __METHOD__ );
1769                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1770                         $ret = $this->getFullURL( $query, $query2, $proto );
1771                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1772                         $ret = $this->getFragmentForURL();
1773                 } else {
1774                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1775                 }
1776                 wfProfileOut( __METHOD__ );
1777                 return $ret;
1778         }
1779
1780         /**
1781          * Get the URL form for an internal link.
1782          * - Used in various Squid-related code, in case we have a different
1783          * internal hostname for the server from the exposed one.
1784          *
1785          * This uses $wgInternalServer to qualify the path, or $wgServer
1786          * if $wgInternalServer is not set. If the server variable used is
1787          * protocol-relative, the URL will be expanded to http://
1788          *
1789          * @see self::getLocalURL for the arguments.
1790          * @return string The URL
1791          */
1792         public function getInternalURL( $query = '', $query2 = false ) {
1793                 global $wgInternalServer, $wgServer;
1794                 $query = self::fixUrlQueryArgs( $query, $query2 );
1795                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1796                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1797                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1798                 return $url;
1799         }
1800
1801         /**
1802          * Get the URL for a canonical link, for use in things like IRC and
1803          * e-mail notifications. Uses $wgCanonicalServer and the
1804          * GetCanonicalURL hook.
1805          *
1806          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1807          *
1808          * @see self::getLocalURL for the arguments.
1809          * @return string The URL
1810          * @since 1.18
1811          */
1812         public function getCanonicalURL( $query = '', $query2 = false ) {
1813                 $query = self::fixUrlQueryArgs( $query, $query2 );
1814                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1815                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1816                 return $url;
1817         }
1818
1819         /**
1820          * Get the edit URL for this Title
1821          *
1822          * @return string The URL, or a null string if this is an interwiki link
1823          */
1824         public function getEditURL() {
1825                 if ( $this->isExternal() ) {
1826                         return '';
1827                 }
1828                 $s = $this->getLocalURL( 'action=edit' );
1829
1830                 return $s;
1831         }
1832
1833         /**
1834          * Is $wgUser watching this page?
1835          *
1836          * @deprecated since 1.20; use User::isWatched() instead.
1837          * @return bool
1838          */
1839         public function userIsWatching() {
1840                 global $wgUser;
1841
1842                 if ( is_null( $this->mWatched ) ) {
1843                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1844                                 $this->mWatched = false;
1845                         } else {
1846                                 $this->mWatched = $wgUser->isWatched( $this );
1847                         }
1848                 }
1849                 return $this->mWatched;
1850         }
1851
1852         /**
1853          * Can $user perform $action on this page?
1854          * This skips potentially expensive cascading permission checks
1855          * as well as avoids expensive error formatting
1856          *
1857          * Suitable for use for nonessential UI controls in common cases, but
1858          * _not_ for functional access control.
1859          *
1860          * May provide false positives, but should never provide a false negative.
1861          *
1862          * @param string $action Action that permission needs to be checked for
1863          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1864          * @return bool
1865          */
1866         public function quickUserCan( $action, $user = null ) {
1867                 return $this->userCan( $action, $user, false );
1868         }
1869
1870         /**
1871          * Can $user perform $action on this page?
1872          *
1873          * @param string $action Action that permission needs to be checked for
1874          * @param User $user User to check (since 1.19); $wgUser will be used if not
1875          *   provided.
1876          * @param bool $doExpensiveQueries Set this to false to avoid doing
1877          *   unnecessary queries.
1878          * @return bool
1879          */
1880         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1881                 if ( !$user instanceof User ) {
1882                         global $wgUser;
1883                         $user = $wgUser;
1884                 }
1885
1886                 return !count( $this->getUserPermissionsErrorsInternal(
1887                         $action, $user, $doExpensiveQueries, true ) );
1888         }
1889
1890         /**
1891          * Can $user perform $action on this page?
1892          *
1893          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1894          *
1895          * @param string $action Action that permission needs to be checked for
1896          * @param User $user User to check
1897          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1898          *   queries by skipping checks for cascading protections and user blocks.
1899          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1900          *   whose corresponding errors may be ignored.
1901          * @return array Array of arguments to wfMessage to explain permissions problems.
1902          */
1903         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true,
1904                 $ignoreErrors = array()
1905         ) {
1906                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1907
1908                 // Remove the errors being ignored.
1909                 foreach ( $errors as $index => $error ) {
1910                         $error_key = is_array( $error ) ? $error[0] : $error;
1911
1912                         if ( in_array( $error_key, $ignoreErrors ) ) {
1913                                 unset( $errors[$index] );
1914                         }
1915                 }
1916
1917                 return $errors;
1918         }
1919
1920         /**
1921          * Permissions checks that fail most often, and which are easiest to test.
1922          *
1923          * @param string $action The action to check
1924          * @param User $user User to check
1925          * @param array $errors List of current errors
1926          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
1927          * @param bool $short Short circuit on first error
1928          *
1929          * @return array List of errors
1930          */
1931         private function checkQuickPermissions( $action, $user, $errors,
1932                 $doExpensiveQueries, $short
1933         ) {
1934                 if ( !wfRunHooks( 'TitleQuickPermissions',
1935                         array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) )
1936                 ) {
1937                         return $errors;
1938                 }
1939
1940                 if ( $action == 'create' ) {
1941                         if (
1942                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1943                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1944                         ) {
1945                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1946                         }
1947                 } elseif ( $action == 'move' ) {
1948                         if ( !$user->isAllowed( 'move-rootuserpages' )
1949                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1950                                 // Show user page-specific message only if the user can move other pages
1951                                 $errors[] = array( 'cant-move-user-page' );
1952                         }
1953
1954                         // Check if user is allowed to move files if it's a file
1955                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1956                                 $errors[] = array( 'movenotallowedfile' );
1957                         }
1958
1959                         // Check if user is allowed to move category pages if it's a category page
1960                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
1961                                 $errors[] = array( 'cant-move-category-page' );
1962                         }
1963
1964                         if ( !$user->isAllowed( 'move' ) ) {
1965                                 // User can't move anything
1966                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1967                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1968                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1969                                         // custom message if logged-in users without any special rights can move
1970                                         $errors[] = array( 'movenologintext' );
1971                                 } else {
1972                                         $errors[] = array( 'movenotallowed' );
1973                                 }
1974                         }
1975                 } elseif ( $action == 'move-target' ) {
1976                         if ( !$user->isAllowed( 'move' ) ) {
1977                                 // User can't move anything
1978                                 $errors[] = array( 'movenotallowed' );
1979                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1980                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1981                                 // Show user page-specific message only if the user can move other pages
1982                                 $errors[] = array( 'cant-move-to-user-page' );
1983                         } elseif ( !$user->isAllowed( 'move-categorypages' )
1984                                         && $this->mNamespace == NS_CATEGORY ) {
1985                                 // Show category page-specific message only if the user can move other pages
1986                                 $errors[] = array( 'cant-move-to-category-page' );
1987                         }
1988                 } elseif ( !$user->isAllowed( $action ) ) {
1989                         $errors[] = $this->missingPermissionError( $action, $short );
1990                 }
1991
1992                 return $errors;
1993         }
1994
1995         /**
1996          * Add the resulting error code to the errors array
1997          *
1998          * @param array $errors List of current errors
1999          * @param array $result Result of errors
2000          *
2001          * @return array List of errors
2002          */
2003         private function resultToError( $errors, $result ) {
2004                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2005                         // A single array representing an error
2006                         $errors[] = $result;
2007                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2008                         // A nested array representing multiple errors
2009                         $errors = array_merge( $errors, $result );
2010                 } elseif ( $result !== '' && is_string( $result ) ) {
2011                         // A string representing a message-id
2012                         $errors[] = array( $result );
2013                 } elseif ( $result === false ) {
2014                         // a generic "We don't want them to do that"
2015                         $errors[] = array( 'badaccess-group0' );
2016                 }
2017                 return $errors;
2018         }
2019
2020         /**
2021          * Check various permission hooks
2022          *
2023          * @param string $action The action to check
2024          * @param User $user User to check
2025          * @param array $errors List of current errors
2026          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2027          * @param bool $short Short circuit on first error
2028          *
2029          * @return array List of errors
2030          */
2031         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
2032                 // Use getUserPermissionsErrors instead
2033                 $result = '';
2034                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2035                         return $result ? array() : array( array( 'badaccess-group0' ) );
2036                 }
2037                 // Check getUserPermissionsErrors hook
2038                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2039                         $errors = $this->resultToError( $errors, $result );
2040                 }
2041                 // Check getUserPermissionsErrorsExpensive hook
2042                 if (
2043                         $doExpensiveQueries
2044                         && !( $short && count( $errors ) > 0 )
2045                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2046                 ) {
2047                         $errors = $this->resultToError( $errors, $result );
2048                 }
2049
2050                 return $errors;
2051         }
2052
2053         /**
2054          * Check permissions on special pages & namespaces
2055          *
2056          * @param string $action The action to check
2057          * @param User $user User to check
2058          * @param array $errors List of current errors
2059          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2060          * @param bool $short Short circuit on first error
2061          *
2062          * @return array List of errors
2063          */
2064         private function checkSpecialsAndNSPermissions( $action, $user, $errors,
2065                 $doExpensiveQueries, $short
2066         ) {
2067                 # Only 'createaccount' can be performed on special pages,
2068                 # which don't actually exist in the DB.
2069                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2070                         $errors[] = array( 'ns-specialprotected' );
2071                 }
2072
2073                 # Check $wgNamespaceProtection for restricted namespaces
2074                 if ( $this->isNamespaceProtected( $user ) ) {
2075                         $ns = $this->mNamespace == NS_MAIN ?
2076                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2077                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2078                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
2079                 }
2080
2081                 return $errors;
2082         }
2083
2084         /**
2085          * Check CSS/JS sub-page permissions
2086          *
2087          * @param string $action The action to check
2088          * @param User $user User to check
2089          * @param array $errors List of current errors
2090          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2091          * @param bool $short Short circuit on first error
2092          *
2093          * @return array List of errors
2094          */
2095         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2096                 # Protect css/js subpages of user pages
2097                 # XXX: this might be better using restrictions
2098                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2099                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2100                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2101                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2102                                         $errors[] = array( 'mycustomcssprotected' );
2103                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2104                                         $errors[] = array( 'mycustomjsprotected' );
2105                                 }
2106                         } else {
2107                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2108                                         $errors[] = array( 'customcssprotected' );
2109                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2110                                         $errors[] = array( 'customjsprotected' );
2111                                 }
2112                         }
2113                 }
2114
2115                 return $errors;
2116         }
2117
2118         /**
2119          * Check against page_restrictions table requirements on this
2120          * page. The user must possess all required rights for this
2121          * action.
2122          *
2123          * @param string $action The action to check
2124          * @param User $user User to check
2125          * @param array $errors List of current errors
2126          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2127          * @param bool $short Short circuit on first error
2128          *
2129          * @return array List of errors
2130          */
2131         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2132                 foreach ( $this->getRestrictions( $action ) as $right ) {
2133                         // Backwards compatibility, rewrite sysop -> editprotected
2134                         if ( $right == 'sysop' ) {
2135                                 $right = 'editprotected';
2136                         }
2137                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2138                         if ( $right == 'autoconfirmed' ) {
2139                                 $right = 'editsemiprotected';
2140                         }
2141                         if ( $right == '' ) {
2142                                 continue;
2143                         }
2144                         if ( !$user->isAllowed( $right ) ) {
2145                                 $errors[] = array( 'protectedpagetext', $right );
2146                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2147                                 $errors[] = array( 'protectedpagetext', 'protect' );
2148                         }
2149                 }
2150
2151                 return $errors;
2152         }
2153
2154         /**
2155          * Check restrictions on cascading pages.
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 bool $doExpensiveQueries Whether or not to perform expensive queries
2161          * @param bool $short Short circuit on first error
2162          *
2163          * @return array List of errors
2164          */
2165         private function checkCascadingSourcesRestrictions( $action, $user, $errors,
2166                 $doExpensiveQueries, $short
2167         ) {
2168                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2169                         # We /could/ use the protection level on the source page, but it's
2170                         # fairly ugly as we have to establish a precedence hierarchy for pages
2171                         # included by multiple cascade-protected pages. So just restrict
2172                         # it to people with 'protect' permission, as they could remove the
2173                         # protection anyway.
2174                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2175                         # Cascading protection depends on more than this page...
2176                         # Several cascading protected pages may include this page...
2177                         # Check each cascading level
2178                         # This is only for protection restrictions, not for all actions
2179                         if ( isset( $restrictions[$action] ) ) {
2180                                 foreach ( $restrictions[$action] as $right ) {
2181                                         // Backwards compatibility, rewrite sysop -> editprotected
2182                                         if ( $right == 'sysop' ) {
2183                                                 $right = 'editprotected';
2184                                         }
2185                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2186                                         if ( $right == 'autoconfirmed' ) {
2187                                                 $right = 'editsemiprotected';
2188                                         }
2189                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2190                                                 $pages = '';
2191                                                 foreach ( $cascadingSources as $page ) {
2192                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2193                                                 }
2194                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2195                                         }
2196                                 }
2197                         }
2198                 }
2199
2200                 return $errors;
2201         }
2202
2203         /**
2204          * Check action permissions not already checked in checkQuickPermissions
2205          *
2206          * @param string $action The action to check
2207          * @param User $user User to check
2208          * @param array $errors List of current errors
2209          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2210          * @param bool $short Short circuit on first error
2211          *
2212          * @return array List of errors
2213          */
2214         private function checkActionPermissions( $action, $user, $errors,
2215                 $doExpensiveQueries, $short
2216         ) {
2217                 global $wgDeleteRevisionsLimit, $wgLang;
2218
2219                 if ( $action == 'protect' ) {
2220                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit',
2221                                 $user, $doExpensiveQueries, true ) )
2222                         ) {
2223                                 // If they can't edit, they shouldn't protect.
2224                                 $errors[] = array( 'protect-cantedit' );
2225                         }
2226                 } elseif ( $action == 'create' ) {
2227                         $title_protection = $this->getTitleProtection();
2228                         if ( $title_protection ) {
2229                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2230                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2231                                 }
2232                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2233                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2234                                 }
2235                                 if ( $title_protection['pt_create_perm'] == ''
2236                                         || !$user->isAllowed( $title_protection['pt_create_perm'] )
2237                                 ) {
2238                                         $errors[] = array(
2239                                                 'titleprotected',
2240                                                 User::whoIs( $title_protection['pt_user'] ),
2241                                                 $title_protection['pt_reason']
2242                                         );
2243                                 }
2244                         }
2245                 } elseif ( $action == 'move' ) {
2246                         // Check for immobile pages
2247                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2248                                 // Specific message for this case
2249                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2250                         } elseif ( !$this->isMovable() ) {
2251                                 // Less specific message for rarer cases
2252                                 $errors[] = array( 'immobile-source-page' );
2253                         }
2254                 } elseif ( $action == 'move-target' ) {
2255                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2256                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2257                         } elseif ( !$this->isMovable() ) {
2258                                 $errors[] = array( 'immobile-target-page' );
2259                         }
2260                 } elseif ( $action == 'delete' ) {
2261                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2262                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2263                         ) {
2264                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2265                         }
2266                 }
2267                 return $errors;
2268         }
2269
2270         /**
2271          * Check that the user isn't blocked from editing.
2272          *
2273          * @param string $action The action to check
2274          * @param User $user User to check
2275          * @param array $errors List of current errors
2276          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2277          * @param bool $short Short circuit on first error
2278          *
2279          * @return array List of errors
2280          */
2281         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2282                 // Account creation blocks handled at userlogin.
2283                 // Unblocking handled in SpecialUnblock
2284                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2285                         return $errors;
2286                 }
2287
2288                 global $wgEmailConfirmToEdit;
2289
2290                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2291                         $errors[] = array( 'confirmedittext' );
2292                 }
2293
2294                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2295                         // Don't block the user from editing their own talk page unless they've been
2296                         // explicitly blocked from that too.
2297                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2298                         // @todo FIXME: Pass the relevant context into this function.
2299                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2300                 }
2301
2302                 return $errors;
2303         }
2304
2305         /**
2306          * Check that the user is allowed to read this page.
2307          *
2308          * @param string $action The action to check
2309          * @param User $user User to check
2310          * @param array $errors List of current errors
2311          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2312          * @param bool $short Short circuit on first error
2313          *
2314          * @return array List of errors
2315          */
2316         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2317                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2318
2319                 $whitelisted = false;
2320                 if ( User::isEveryoneAllowed( 'read' ) ) {
2321                         # Shortcut for public wikis, allows skipping quite a bit of code
2322                         $whitelisted = true;
2323                 } elseif ( $user->isAllowed( 'read' ) ) {
2324                         # If the user is allowed to read pages, he is allowed to read all pages
2325                         $whitelisted = true;
2326                 } elseif ( $this->isSpecial( 'Userlogin' )
2327                         || $this->isSpecial( 'ChangePassword' )
2328                         || $this->isSpecial( 'PasswordReset' )
2329                 ) {
2330                         # Always grant access to the login page.
2331                         # Even anons need to be able to log in.
2332                         $whitelisted = true;
2333                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2334                         # Time to check the whitelist
2335                         # Only do these checks is there's something to check against
2336                         $name = $this->getPrefixedText();
2337                         $dbName = $this->getPrefixedDBkey();
2338
2339                         // Check for explicit whitelisting with and without underscores
2340                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2341                                 $whitelisted = true;
2342                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2343                                 # Old settings might have the title prefixed with
2344                                 # a colon for main-namespace pages
2345                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2346                                         $whitelisted = true;
2347                                 }
2348                         } elseif ( $this->isSpecialPage() ) {
2349                                 # If it's a special page, ditch the subpage bit and check again
2350                                 $name = $this->getDBkey();
2351                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2352                                 if ( $name ) {
2353                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2354                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2355                                                 $whitelisted = true;
2356                                         }
2357                                 }
2358                         }
2359                 }
2360
2361                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2362                         $name = $this->getPrefixedText();
2363                         // Check for regex whitelisting
2364                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2365                                 if ( preg_match( $listItem, $name ) ) {
2366                                         $whitelisted = true;
2367                                         break;
2368                                 }
2369                         }
2370                 }
2371
2372                 if ( !$whitelisted ) {
2373                         # If the title is not whitelisted, give extensions a chance to do so...
2374                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2375                         if ( !$whitelisted ) {
2376                                 $errors[] = $this->missingPermissionError( $action, $short );
2377                         }
2378                 }
2379
2380                 return $errors;
2381         }
2382
2383         /**
2384          * Get a description array when the user doesn't have the right to perform
2385          * $action (i.e. when User::isAllowed() returns false)
2386          *
2387          * @param string $action The action to check
2388          * @param bool $short Short circuit on first error
2389          * @return array List of errors
2390          */
2391         private function missingPermissionError( $action, $short ) {
2392                 // We avoid expensive display logic for quickUserCan's and such
2393                 if ( $short ) {
2394                         return array( 'badaccess-group0' );
2395                 }
2396
2397                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2398                         User::getGroupsWithPermission( $action ) );
2399
2400                 if ( count( $groups ) ) {
2401                         global $wgLang;
2402                         return array(
2403                                 'badaccess-groups',
2404                                 $wgLang->commaList( $groups ),
2405                                 count( $groups )
2406                         );
2407                 } else {
2408                         return array( 'badaccess-group0' );
2409                 }
2410         }
2411
2412         /**
2413          * Can $user perform $action on this page? This is an internal function,
2414          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2415          * checks on wfReadOnly() and blocks)
2416          *
2417          * @param string $action Action that permission needs to be checked for
2418          * @param User $user User to check
2419          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2420          * @param bool $short Set this to true to stop after the first permission error.
2421          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2422          */
2423         protected function getUserPermissionsErrorsInternal( $action, $user,
2424                 $doExpensiveQueries = true, $short = false
2425         ) {
2426                 wfProfileIn( __METHOD__ );
2427
2428                 # Read has special handling
2429                 if ( $action == 'read' ) {
2430                         $checks = array(
2431                                 'checkPermissionHooks',
2432                                 'checkReadPermissions',
2433                         );
2434                 } else {
2435                         $checks = array(
2436                                 'checkQuickPermissions',
2437                                 'checkPermissionHooks',
2438                                 'checkSpecialsAndNSPermissions',
2439                                 'checkCSSandJSPermissions',
2440                                 'checkPageRestrictions',
2441                                 'checkCascadingSourcesRestrictions',
2442                                 'checkActionPermissions',
2443                                 'checkUserBlock'
2444                         );
2445                 }
2446
2447                 $errors = array();
2448                 while ( count( $checks ) > 0 &&
2449                                 !( $short && count( $errors ) > 0 ) ) {
2450                         $method = array_shift( $checks );
2451                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2452                 }
2453
2454                 wfProfileOut( __METHOD__ );
2455                 return $errors;
2456         }
2457
2458         /**
2459          * Get a filtered list of all restriction types supported by this wiki.
2460          * @param bool $exists True to get all restriction types that apply to
2461          * titles that do exist, False for all restriction types that apply to
2462          * titles that do not exist
2463          * @return array
2464          */
2465         public static function getFilteredRestrictionTypes( $exists = true ) {
2466                 global $wgRestrictionTypes;
2467                 $types = $wgRestrictionTypes;
2468                 if ( $exists ) {
2469                         # Remove the create restriction for existing titles
2470                         $types = array_diff( $types, array( 'create' ) );
2471                 } else {
2472                         # Only the create and upload restrictions apply to non-existing titles
2473                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2474                 }
2475                 return $types;
2476         }
2477
2478         /**
2479          * Returns restriction types for the current Title
2480          *
2481          * @return array Applicable restriction types
2482          */
2483         public function getRestrictionTypes() {
2484                 if ( $this->isSpecialPage() ) {
2485                         return array();
2486                 }
2487
2488                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2489
2490                 if ( $this->getNamespace() != NS_FILE ) {
2491                         # Remove the upload restriction for non-file titles
2492                         $types = array_diff( $types, array( 'upload' ) );
2493                 }
2494
2495                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2496
2497                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2498                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2499
2500                 return $types;
2501         }
2502
2503         /**
2504          * Is this title subject to title protection?
2505          * Title protection is the one applied against creation of such title.
2506          *
2507          * @return array|bool An associative array representing any existent title
2508          *   protection, or false if there's none.
2509          */
2510         private function getTitleProtection() {
2511                 // Can't protect pages in special namespaces
2512                 if ( $this->getNamespace() < 0 ) {
2513                         return false;
2514                 }
2515
2516                 // Can't protect pages that exist.
2517                 if ( $this->exists() ) {
2518                         return false;
2519                 }
2520
2521                 if ( $this->mTitleProtection === null ) {
2522                         $dbr = wfGetDB( DB_SLAVE );
2523                         $res = $dbr->select(
2524                                 'protected_titles',
2525                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2526                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2527                                 __METHOD__
2528                         );
2529
2530                         // fetchRow returns false if there are no rows.
2531                         $this->mTitleProtection = $dbr->fetchRow( $res );
2532                 }
2533                 return $this->mTitleProtection;
2534         }
2535
2536         /**
2537          * Remove any title protection due to page existing
2538          */
2539         public function deleteTitleProtection() {
2540                 $dbw = wfGetDB( DB_MASTER );
2541
2542                 $dbw->delete(
2543                         'protected_titles',
2544                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2545                         __METHOD__
2546                 );
2547                 $this->mTitleProtection = false;
2548         }
2549
2550         /**
2551          * Is this page "semi-protected" - the *only* protection levels are listed
2552          * in $wgSemiprotectedRestrictionLevels?
2553          *
2554          * @param string $action Action to check (default: edit)
2555          * @return bool
2556          */
2557         public function isSemiProtected( $action = 'edit' ) {
2558                 global $wgSemiprotectedRestrictionLevels;
2559
2560                 $restrictions = $this->getRestrictions( $action );
2561                 $semi = $wgSemiprotectedRestrictionLevels;
2562                 if ( !$restrictions || !$semi ) {
2563                         // Not protected, or all protection is full protection
2564                         return false;
2565                 }
2566
2567                 // Remap autoconfirmed to editsemiprotected for BC
2568                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2569                         $semi[$key] = 'editsemiprotected';
2570                 }
2571                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2572                         $restrictions[$key] = 'editsemiprotected';
2573                 }
2574
2575                 return !array_diff( $restrictions, $semi );
2576         }
2577
2578         /**
2579          * Does the title correspond to a protected article?
2580          *
2581          * @param string $action The action the page is protected from,
2582          * by default checks all actions.
2583          * @return bool
2584          */
2585         public function isProtected( $action = '' ) {
2586                 global $wgRestrictionLevels;
2587
2588                 $restrictionTypes = $this->getRestrictionTypes();
2589
2590                 # Special pages have inherent protection
2591                 if ( $this->isSpecialPage() ) {
2592                         return true;
2593                 }
2594
2595                 # Check regular protection levels
2596                 foreach ( $restrictionTypes as $type ) {
2597                         if ( $action == $type || $action == '' ) {
2598                                 $r = $this->getRestrictions( $type );
2599                                 foreach ( $wgRestrictionLevels as $level ) {
2600                                         if ( in_array( $level, $r ) && $level != '' ) {
2601                                                 return true;
2602                                         }
2603                                 }
2604                         }
2605                 }
2606
2607                 return false;
2608         }
2609
2610         /**
2611          * Determines if $user is unable to edit this page because it has been protected
2612          * by $wgNamespaceProtection.
2613          *
2614          * @param User $user User object to check permissions
2615          * @return bool
2616          */
2617         public function isNamespaceProtected( User $user ) {
2618                 global $wgNamespaceProtection;
2619
2620                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2621                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2622                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2623                                         return true;
2624                                 }
2625                         }
2626                 }
2627                 return false;
2628         }
2629
2630         /**
2631          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2632          *
2633          * @return bool If the page is subject to cascading restrictions.
2634          */
2635         public function isCascadeProtected() {
2636                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2637                 return ( $sources > 0 );
2638         }
2639
2640         /**
2641          * Determines whether cascading protection sources have already been loaded from
2642          * the database.
2643          *
2644          * @param bool $getPages True to check if the pages are loaded, or false to check
2645          * if the status is loaded.
2646          * @return bool Whether or not the specified information has been loaded
2647          * @since 1.23
2648          */
2649         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2650                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2651         }
2652
2653         /**
2654          * Cascading protection: Get the source of any cascading restrictions on this page.
2655          *
2656          * @param bool $getPages Whether or not to retrieve the actual pages
2657          *        that the restrictions have come from and the actual restrictions
2658          *        themselves.
2659          * @return array Two elements: First is an array of Title objects of the
2660          *        pages from which cascading restrictions have come, false for
2661          *        none, or true if such restrictions exist but $getPages was not
2662          *        set. Second is an array like that returned by
2663          *        Title::getAllRestrictions(), or an empty array if $getPages is
2664          *        false.
2665          */
2666         public function getCascadeProtectionSources( $getPages = true ) {
2667                 global $wgContLang;
2668                 $pagerestrictions = array();
2669
2670                 if ( $this->mCascadeSources !== null && $getPages ) {
2671                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2672                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2673                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2674                 }
2675
2676                 wfProfileIn( __METHOD__ );
2677
2678                 $dbr = wfGetDB( DB_SLAVE );
2679
2680                 if ( $this->getNamespace() == NS_FILE ) {
2681                         $tables = array( 'imagelinks', 'page_restrictions' );
2682                         $where_clauses = array(
2683                                 'il_to' => $this->getDBkey(),
2684                                 'il_from=pr_page',
2685                                 'pr_cascade' => 1
2686                         );
2687                 } else {
2688                         $tables = array( 'templatelinks', 'page_restrictions' );
2689                         $where_clauses = array(
2690                                 'tl_namespace' => $this->getNamespace(),
2691                                 'tl_title' => $this->getDBkey(),
2692                                 'tl_from=pr_page',
2693                                 'pr_cascade' => 1
2694                         );
2695                 }
2696
2697                 if ( $getPages ) {
2698                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2699                                 'pr_expiry', 'pr_type', 'pr_level' );
2700                         $where_clauses[] = 'page_id=pr_page';
2701                         $tables[] = 'page';
2702                 } else {
2703                         $cols = array( 'pr_expiry' );
2704                 }
2705
2706                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2707
2708                 $sources = $getPages ? array() : false;
2709                 $now = wfTimestampNow();
2710                 $purgeExpired = false;
2711
2712                 foreach ( $res as $row ) {
2713                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2714                         if ( $expiry > $now ) {
2715                                 if ( $getPages ) {
2716                                         $page_id = $row->pr_page;
2717                                         $page_ns = $row->page_namespace;
2718                                         $page_title = $row->page_title;
2719                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2720                                         # Add groups needed for each restriction type if its not already there
2721                                         # Make sure this restriction type still exists
2722
2723                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2724                                                 $pagerestrictions[$row->pr_type] = array();
2725                                         }
2726
2727                                         if (
2728                                                 isset( $pagerestrictions[$row->pr_type] )
2729                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2730                                         ) {
2731                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2732                                         }
2733                                 } else {
2734                                         $sources = true;
2735                                 }
2736                         } else {
2737                                 // Trigger lazy purge of expired restrictions from the db
2738                                 $purgeExpired = true;
2739                         }
2740                 }
2741                 if ( $purgeExpired ) {
2742                         Title::purgeExpiredRestrictions();
2743                 }
2744
2745                 if ( $getPages ) {
2746                         $this->mCascadeSources = $sources;
2747                         $this->mCascadingRestrictions = $pagerestrictions;
2748                 } else {
2749                         $this->mHasCascadingRestrictions = $sources;
2750                 }
2751
2752                 wfProfileOut( __METHOD__ );
2753                 return array( $sources, $pagerestrictions );
2754         }
2755
2756         /**
2757          * Accessor for mRestrictionsLoaded
2758          *
2759          * @return bool Whether or not the page's restrictions have already been
2760          * loaded from the database
2761          * @since 1.23
2762          */
2763         public function areRestrictionsLoaded() {
2764                 return $this->mRestrictionsLoaded;
2765         }
2766
2767         /**
2768          * Accessor/initialisation for mRestrictions
2769          *
2770          * @param string $action Action that permission needs to be checked for
2771          * @return array Restriction levels needed to take the action. All levels
2772          *     are required.
2773          */
2774         public function getRestrictions( $action ) {
2775                 if ( !$this->mRestrictionsLoaded ) {
2776                         $this->loadRestrictions();
2777                 }
2778                 return isset( $this->mRestrictions[$action] )
2779                                 ? $this->mRestrictions[$action]
2780                                 : array();
2781         }
2782
2783         /**
2784          * Accessor/initialisation for mRestrictions
2785          *
2786          * @return array Keys are actions, values are arrays as returned by
2787          *     Title::getRestrictions()
2788          * @since 1.23
2789          */
2790         public function getAllRestrictions() {
2791                 if ( !$this->mRestrictionsLoaded ) {
2792                         $this->loadRestrictions();
2793                 }
2794                 return $this->mRestrictions;
2795         }
2796
2797         /**
2798          * Get the expiry time for the restriction against a given action
2799          *
2800          * @param string $action
2801          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2802          *     or not protected at all, or false if the action is not recognised.
2803          */
2804         public function getRestrictionExpiry( $action ) {
2805                 if ( !$this->mRestrictionsLoaded ) {
2806                         $this->loadRestrictions();
2807                 }
2808                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2809         }
2810
2811         /**
2812          * Returns cascading restrictions for the current article
2813          *
2814          * @return bool
2815          */
2816         function areRestrictionsCascading() {
2817                 if ( !$this->mRestrictionsLoaded ) {
2818                         $this->loadRestrictions();
2819                 }
2820
2821                 return $this->mCascadeRestriction;
2822         }
2823
2824         /**
2825          * Loads a string into mRestrictions array
2826          *
2827          * @param ResultWrapper $res Resource restrictions as an SQL result.
2828          * @param string $oldFashionedRestrictions Comma-separated list of page
2829          *        restrictions from page table (pre 1.10)
2830          */
2831         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2832                 $rows = array();
2833
2834                 foreach ( $res as $row ) {
2835                         $rows[] = $row;
2836                 }
2837
2838                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2839         }
2840
2841         /**
2842          * Compiles list of active page restrictions from both page table (pre 1.10)
2843          * and page_restrictions table for this existing page.
2844          * Public for usage by LiquidThreads.
2845          *
2846          * @param array $rows Array of db result objects
2847          * @param string $oldFashionedRestrictions Comma-separated list of page
2848          *   restrictions from page table (pre 1.10)
2849          */
2850         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2851                 global $wgContLang;
2852                 $dbr = wfGetDB( DB_SLAVE );
2853
2854                 $restrictionTypes = $this->getRestrictionTypes();
2855
2856                 foreach ( $restrictionTypes as $type ) {
2857                         $this->mRestrictions[$type] = array();
2858                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2859                 }
2860
2861                 $this->mCascadeRestriction = false;
2862
2863                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2864
2865                 if ( $oldFashionedRestrictions === null ) {
2866                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2867                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2868                 }
2869
2870                 if ( $oldFashionedRestrictions != '' ) {
2871
2872                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2873                                 $temp = explode( '=', trim( $restrict ) );
2874                                 if ( count( $temp ) == 1 ) {
2875                                         // old old format should be treated as edit/move restriction
2876                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2877                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2878                                 } else {
2879                                         $restriction = trim( $temp[1] );
2880                                         if ( $restriction != '' ) { //some old entries are empty
2881                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2882                                         }
2883                                 }
2884                         }
2885
2886                         $this->mOldRestrictions = true;
2887
2888                 }
2889
2890                 if ( count( $rows ) ) {
2891                         # Current system - load second to make them override.
2892                         $now = wfTimestampNow();
2893                         $purgeExpired = false;
2894
2895                         # Cycle through all the restrictions.
2896                         foreach ( $rows as $row ) {
2897
2898                                 // Don't take care of restrictions types that aren't allowed
2899                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2900                                         continue;
2901                                 }
2902
2903                                 // This code should be refactored, now that it's being used more generally,
2904                                 // But I don't really see any harm in leaving it in Block for now -werdna
2905                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2906
2907                                 // Only apply the restrictions if they haven't expired!
2908                                 if ( !$expiry || $expiry > $now ) {
2909                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2910                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2911
2912                                         $this->mCascadeRestriction |= $row->pr_cascade;
2913                                 } else {
2914                                         // Trigger a lazy purge of expired restrictions
2915                                         $purgeExpired = true;
2916                                 }
2917                         }
2918
2919                         if ( $purgeExpired ) {
2920                                 Title::purgeExpiredRestrictions();
2921                         }
2922                 }
2923
2924                 $this->mRestrictionsLoaded = true;
2925         }
2926
2927         /**
2928          * Load restrictions from the page_restrictions table
2929          *
2930          * @param string $oldFashionedRestrictions Comma-separated list of page
2931          *   restrictions from page table (pre 1.10)
2932          */
2933         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2934                 global $wgContLang;
2935                 if ( !$this->mRestrictionsLoaded ) {
2936                         if ( $this->exists() ) {
2937                                 $dbr = wfGetDB( DB_SLAVE );
2938
2939                                 $res = $dbr->select(
2940                                         'page_restrictions',
2941                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2942                                         array( 'pr_page' => $this->getArticleID() ),
2943                                         __METHOD__
2944                                 );
2945
2946                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2947                         } else {
2948                                 $title_protection = $this->getTitleProtection();
2949
2950                                 if ( $title_protection ) {
2951                                         $now = wfTimestampNow();
2952                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2953
2954                                         if ( !$expiry || $expiry > $now ) {
2955                                                 // Apply the restrictions
2956                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2957                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2958                                         } else { // Get rid of the old restrictions
2959                                                 Title::purgeExpiredRestrictions();
2960                                                 $this->mTitleProtection = false;
2961                                         }
2962                                 } else {
2963                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2964                                 }
2965                                 $this->mRestrictionsLoaded = true;
2966                         }
2967                 }
2968         }
2969
2970         /**
2971          * Flush the protection cache in this object and force reload from the database.
2972          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2973          */
2974         public function flushRestrictions() {
2975                 $this->mRestrictionsLoaded = false;
2976                 $this->mTitleProtection = null;
2977         }
2978
2979         /**
2980          * Purge expired restrictions from the page_restrictions table
2981          */
2982         static function purgeExpiredRestrictions() {
2983                 if ( wfReadOnly() ) {
2984                         return;
2985                 }
2986
2987                 $method = __METHOD__;
2988                 $dbw = wfGetDB( DB_MASTER );
2989                 $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
2990                         $dbw->delete(
2991                                 'page_restrictions',
2992                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2993                                 $method
2994                         );
2995                         $dbw->delete(
2996                                 'protected_titles',
2997                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2998                                 $method
2999                         );
3000                 } );
3001         }
3002
3003         /**
3004          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3005          *
3006          * @return bool
3007          */
3008         public function hasSubpages() {
3009                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3010                         # Duh
3011                         return false;
3012                 }
3013
3014                 # We dynamically add a member variable for the purpose of this method
3015                 # alone to cache the result.  There's no point in having it hanging
3016                 # around uninitialized in every Title object; therefore we only add it
3017                 # if needed and don't declare it statically.
3018                 if ( $this->mHasSubpages === null ) {
3019                         $this->mHasSubpages = false;
3020                         $subpages = $this->getSubpages( 1 );
3021                         if ( $subpages instanceof TitleArray ) {
3022                                 $this->mHasSubpages = (bool)$subpages->count();
3023                         }
3024                 }
3025
3026                 return $this->mHasSubpages;
3027         }
3028
3029         /**
3030          * Get all subpages of this page.
3031          *
3032          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3033          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3034          *  doesn't allow subpages
3035          */
3036         public function getSubpages( $limit = -1 ) {
3037                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3038                         return array();
3039                 }
3040
3041                 $dbr = wfGetDB( DB_SLAVE );
3042                 $conds['page_namespace'] = $this->getNamespace();
3043                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3044                 $options = array();
3045                 if ( $limit > -1 ) {
3046                         $options['LIMIT'] = $limit;
3047                 }
3048                 $this->mSubpages = TitleArray::newFromResult(
3049                         $dbr->select( 'page',
3050                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3051                                 $conds,
3052                                 __METHOD__,
3053                                 $options
3054                         )
3055                 );
3056                 return $this->mSubpages;
3057         }
3058
3059         /**
3060          * Is there a version of this page in the deletion archive?
3061          *
3062          * @return int The number of archived revisions
3063          */
3064         public function isDeleted() {
3065                 if ( $this->getNamespace() < 0 ) {
3066                         $n = 0;
3067                 } else {
3068                         $dbr = wfGetDB( DB_SLAVE );
3069
3070                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3071                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3072                                 __METHOD__
3073                         );
3074                         if ( $this->getNamespace() == NS_FILE ) {
3075                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3076                                         array( 'fa_name' => $this->getDBkey() ),
3077                                         __METHOD__
3078                                 );
3079                         }
3080                 }
3081                 return (int)$n;
3082         }
3083
3084         /**
3085          * Is there a version of this page in the deletion archive?
3086          *
3087          * @return bool
3088          */
3089         public function isDeletedQuick() {
3090                 if ( $this->getNamespace() < 0 ) {
3091                         return false;
3092                 }
3093                 $dbr = wfGetDB( DB_SLAVE );
3094                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3095                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3096                         __METHOD__
3097                 );
3098                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3099                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3100                                 array( 'fa_name' => $this->getDBkey() ),
3101                                 __METHOD__
3102                         );
3103                 }
3104                 return $deleted;
3105         }
3106
3107         /**
3108          * Get the article ID for this Title from the link cache,
3109          * adding it if necessary
3110          *
3111          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3112          *  for update
3113          * @return int The ID
3114          */
3115         public function getArticleID( $flags = 0 ) {
3116                 if ( $this->getNamespace() < 0 ) {
3117                         $this->mArticleID = 0;
3118                         return $this->mArticleID;
3119                 }
3120                 $linkCache = LinkCache::singleton();
3121                 if ( $flags & self::GAID_FOR_UPDATE ) {
3122                         $oldUpdate = $linkCache->forUpdate( true );
3123                         $linkCache->clearLink( $this );
3124                         $this->mArticleID = $linkCache->addLinkObj( $this );
3125                         $linkCache->forUpdate( $oldUpdate );
3126                 } else {
3127                         if ( -1 == $this->mArticleID ) {
3128                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3129                         }
3130                 }
3131                 return $this->mArticleID;
3132         }
3133
3134         /**
3135          * Is this an article that is a redirect page?
3136          * Uses link cache, adding it if necessary
3137          *
3138          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3139          * @return bool
3140          */
3141         public function isRedirect( $flags = 0 ) {
3142                 if ( !is_null( $this->mRedirect ) ) {
3143                         return $this->mRedirect;
3144                 }
3145                 # Calling getArticleID() loads the field from cache as needed
3146                 if ( !$this->getArticleID( $flags ) ) {
3147                         $this->mRedirect = false;
3148                         return $this->mRedirect;
3149                 }
3150
3151                 $linkCache = LinkCache::singleton();
3152                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3153                 if ( $cached === null ) {
3154                         # Trust LinkCache's state over our own
3155                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3156                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3157                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3158                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3159                         # LinkCache to refresh its data from the master.
3160                         $this->mRedirect = false;
3161                         return $this->mRedirect;
3162                 }
3163
3164                 $this->mRedirect = (bool)$cached;
3165
3166                 return $this->mRedirect;
3167         }
3168
3169         /**
3170          * What is the length of this page?
3171          * Uses link cache, adding it if necessary
3172          *
3173          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3174          * @return int
3175          */
3176         public function getLength( $flags = 0 ) {
3177                 if ( $this->mLength != -1 ) {
3178                         return $this->mLength;
3179                 }
3180                 # Calling getArticleID() loads the field from cache as needed
3181                 if ( !$this->getArticleID( $flags ) ) {
3182                         $this->mLength = 0;
3183                         return $this->mLength;
3184                 }
3185                 $linkCache = LinkCache::singleton();
3186                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3187                 if ( $cached === null ) {
3188                         # Trust LinkCache's state over our own, as for isRedirect()
3189                         $this->mLength = 0;
3190                         return $this->mLength;
3191                 }
3192
3193                 $this->mLength = intval( $cached );
3194
3195                 return $this->mLength;
3196         }
3197
3198         /**
3199          * What is the page_latest field for this page?
3200          *
3201          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3202          * @return int Int or 0 if the page doesn't exist
3203          */
3204         public function getLatestRevID( $flags = 0 ) {
3205                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3206                         return intval( $this->mLatestID );
3207                 }
3208                 # Calling getArticleID() loads the field from cache as needed
3209                 if ( !$this->getArticleID( $flags ) ) {
3210                         $this->mLatestID = 0;
3211                         return $this->mLatestID;
3212                 }
3213                 $linkCache = LinkCache::singleton();
3214                 $linkCache->addLinkObj( $this );
3215                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3216                 if ( $cached === null ) {
3217                         # Trust LinkCache's state over our own, as for isRedirect()
3218                         $this->mLatestID = 0;
3219                         return $this->mLatestID;
3220                 }
3221
3222                 $this->mLatestID = intval( $cached );
3223
3224                 return $this->mLatestID;
3225         }
3226
3227         /**
3228          * This clears some fields in this object, and clears any associated
3229          * keys in the "bad links" section of the link cache.
3230          *
3231          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3232          * loading of the new page_id. It's also called from
3233          * WikiPage::doDeleteArticleReal()
3234          *
3235          * @param int $newid The new Article ID
3236          */
3237         public function resetArticleID( $newid ) {
3238                 $linkCache = LinkCache::singleton();
3239                 $linkCache->clearLink( $this );
3240
3241                 if ( $newid === false ) {
3242                         $this->mArticleID = -1;
3243                 } else {
3244                         $this->mArticleID = intval( $newid );
3245                 }
3246                 $this->mRestrictionsLoaded = false;
3247                 $this->mRestrictions = array();
3248                 $this->mRedirect = null;
3249                 $this->mLength = -1;
3250                 $this->mLatestID = false;
3251                 $this->mContentModel = false;
3252                 $this->mEstimateRevisions = null;
3253                 $this->mPageLanguage = false;
3254                 $this->mDbPageLanguage = null;
3255         }
3256
3257         /**
3258          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3259          *
3260          * @param string $text Containing title to capitalize
3261          * @param int $ns Namespace index, defaults to NS_MAIN
3262          * @return string Containing capitalized title
3263          */
3264         public static function capitalize( $text, $ns = NS_MAIN ) {
3265                 global $wgContLang;
3266
3267                 if ( MWNamespace::isCapitalized( $ns ) ) {
3268                         return $wgContLang->ucfirst( $text );
3269                 } else {
3270                         return $text;
3271                 }
3272         }
3273
3274         /**
3275          * Secure and split - main initialisation function for this object
3276          *
3277          * Assumes that mDbkeyform has been set, and is urldecoded
3278          * and uses underscores, but not otherwise munged.  This function
3279          * removes illegal characters, splits off the interwiki and
3280          * namespace prefixes, sets the other forms, and canonicalizes
3281          * everything.
3282          *
3283          * @return bool True on success
3284          */
3285         private function secureAndSplit() {
3286                 # Initialisation
3287                 $this->mInterwiki = '';
3288                 $this->mFragment = '';
3289                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3290
3291                 $dbkey = $this->mDbkeyform;
3292
3293                 try {
3294                         // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3295                         //        the parsing code with Title, while avoiding massive refactoring.
3296                         // @todo: get rid of secureAndSplit, refactor parsing code.
3297                         $parser = self::getTitleParser();
3298                         $parts = $parser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3299                 } catch ( MalformedTitleException $ex ) {
3300                         return false;
3301                 }
3302
3303                 # Fill fields
3304                 $this->setFragment( '#' . $parts['fragment'] );
3305                 $this->mInterwiki = $parts['interwiki'];
3306                 $this->mLocalInterwiki = $parts['local_interwiki'];
3307                 $this->mNamespace = $parts['namespace'];
3308                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3309
3310                 $this->mDbkeyform = $parts['dbkey'];
3311                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3312                 $this->mTextform = str_replace( '_', ' ', $this->mDbkeyform );
3313
3314                 # We already know that some pages won't be in the database!
3315                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3316                         $this->mArticleID = 0;
3317                 }
3318
3319                 return true;
3320         }
3321
3322         /**
3323          * Get an array of Title objects linking to this Title
3324          * Also stores the IDs in the link cache.
3325          *
3326          * WARNING: do not use this function on arbitrary user-supplied titles!
3327          * On heavily-used templates it will max out the memory.
3328          *
3329          * @param array $options May be FOR UPDATE
3330          * @param string $table Table name
3331          * @param string $prefix Fields prefix
3332          * @return Title[] Array of Title objects linking here
3333          */
3334         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3335                 if ( count( $options ) > 0 ) {
3336                         $db = wfGetDB( DB_MASTER );
3337                 } else {
3338                         $db = wfGetDB( DB_SLAVE );
3339                 }
3340
3341                 $res = $db->select(
3342                         array( 'page', $table ),
3343                         self::getSelectFields(),
3344                         array(
3345                                 "{$prefix}_from=page_id",
3346                                 "{$prefix}_namespace" => $this->getNamespace(),
3347                                 "{$prefix}_title" => $this->getDBkey() ),
3348                         __METHOD__,
3349                         $options
3350                 );
3351
3352                 $retVal = array();
3353                 if ( $res->numRows() ) {
3354                         $linkCache = LinkCache::singleton();
3355                         foreach ( $res as $row ) {
3356                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3357                                 if ( $titleObj ) {
3358                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3359                                         $retVal[] = $titleObj;
3360                                 }
3361                         }
3362                 }
3363                 return $retVal;
3364         }
3365
3366         /**
3367          * Get an array of Title objects using this Title as a template
3368          * Also stores the IDs in the link cache.
3369          *
3370          * WARNING: do not use this function on arbitrary user-supplied titles!
3371          * On heavily-used templates it will max out the memory.
3372          *
3373          * @param array $options May be FOR UPDATE
3374          * @return Title[] Array of Title the Title objects linking here
3375          */
3376         public function getTemplateLinksTo( $options = array() ) {
3377                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3378         }
3379
3380         /**
3381          * Get an array of Title objects linked from this Title
3382          * Also stores the IDs in the link cache.
3383          *
3384          * WARNING: do not use this function on arbitrary user-supplied titles!
3385          * On heavily-used templates it will max out the memory.
3386          *
3387          * @param array $options May be FOR UPDATE
3388          * @param string $table Table name
3389          * @param string $prefix Fields prefix
3390          * @return array Array of Title objects linking here
3391          */
3392         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3393                 global $wgContentHandlerUseDB;
3394
3395                 $id = $this->getArticleID();
3396
3397                 # If the page doesn't exist; there can't be any link from this page
3398                 if ( !$id ) {
3399                         return array();
3400                 }
3401
3402                 if ( count( $options ) > 0 ) {
3403                         $db = wfGetDB( DB_MASTER );
3404                 } else {
3405                         $db = wfGetDB( DB_SLAVE );
3406                 }
3407
3408                 $namespaceFiled = "{$prefix}_namespace";
3409                 $titleField = "{$prefix}_title";
3410
3411                 $fields = array(
3412                         $namespaceFiled,
3413                         $titleField,
3414                         'page_id',
3415                         'page_len',
3416                         'page_is_redirect',
3417                         'page_latest'
3418                 );
3419
3420                 if ( $wgContentHandlerUseDB ) {
3421                         $fields[] = 'page_content_model';
3422                 }
3423
3424                 $res = $db->select(
3425                         array( $table, 'page' ),
3426                         $fields,
3427                         array( "{$prefix}_from" => $id ),
3428                         __METHOD__,
3429                         $options,
3430                         array( 'page' => array(
3431                                 'LEFT JOIN',
3432                                 array( "page_namespace=$namespaceFiled", "page_title=$titleField" )
3433                         ) )
3434                 );
3435
3436                 $retVal = array();
3437                 if ( $res->numRows() ) {
3438                         $linkCache = LinkCache::singleton();
3439                         foreach ( $res as $row ) {
3440                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3441                                 if ( $titleObj ) {
3442                                         if ( $row->page_id ) {
3443                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3444                                         } else {
3445                                                 $linkCache->addBadLinkObj( $titleObj );
3446                                         }
3447                                         $retVal[] = $titleObj;
3448                                 }
3449                         }
3450                 }
3451                 return $retVal;
3452         }
3453
3454         /**
3455          * Get an array of Title objects used on this Title as a template
3456          * Also stores the IDs in the link cache.
3457          *
3458          * WARNING: do not use this function on arbitrary user-supplied titles!
3459          * On heavily-used templates it will max out the memory.
3460          *
3461          * @param array $options May be FOR UPDATE
3462          * @return Title[] Array of Title the Title objects used here
3463          */
3464         public function getTemplateLinksFrom( $options = array() ) {
3465                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3466         }
3467
3468         /**
3469          * Get an array of Title objects referring to non-existent articles linked
3470          * from this page.
3471          *
3472          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3473          *   should use redirect table in this case).
3474          * @return Title[] Array of Title the Title objects
3475          */
3476         public function getBrokenLinksFrom() {
3477                 if ( $this->getArticleID() == 0 ) {
3478                         # All links from article ID 0 are false positives
3479                         return array();
3480                 }
3481
3482                 $dbr = wfGetDB( DB_SLAVE );
3483                 $res = $dbr->select(
3484                         array( 'page', 'pagelinks' ),
3485                         array( 'pl_namespace', 'pl_title' ),
3486                         array(
3487                                 'pl_from' => $this->getArticleID(),
3488                                 'page_namespace IS NULL'
3489                         ),
3490                         __METHOD__, array(),
3491                         array(
3492                                 'page' => array(
3493                                         'LEFT JOIN',
3494                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3495                                 )
3496                         )
3497                 );
3498
3499                 $retVal = array();
3500                 foreach ( $res as $row ) {
3501                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3502                 }
3503                 return $retVal;
3504         }
3505
3506         /**
3507          * Get a list of URLs to purge from the Squid cache when this
3508          * page changes
3509          *
3510          * @return string[] Array of String the URLs
3511          */
3512         public function getSquidURLs() {
3513                 $urls = array(
3514                         $this->getInternalURL(),
3515                         $this->getInternalURL( 'action=history' )
3516                 );
3517
3518                 $pageLang = $this->getPageLanguage();
3519                 if ( $pageLang->hasVariants() ) {
3520                         $variants = $pageLang->getVariants();
3521                         foreach ( $variants as $vCode ) {
3522                                 $urls[] = $this->getInternalURL( '', $vCode );
3523                         }
3524                 }
3525
3526                 // If we are looking at a css/js user subpage, purge the action=raw.
3527                 if ( $this->isJsSubpage() ) {
3528                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3529                 } elseif ( $this->isCssSubpage() ) {
3530                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3531                 }
3532
3533                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3534                 return $urls;
3535         }
3536
3537         /**
3538          * Purge all applicable Squid URLs
3539          */
3540         public function purgeSquid() {
3541                 global $wgUseSquid;
3542                 if ( $wgUseSquid ) {
3543                         $urls = $this->getSquidURLs();
3544                         $u = new SquidUpdate( $urls );
3545                         $u->doUpdate();
3546                 }
3547         }
3548
3549         /**
3550          * Move this page without authentication
3551          *
3552          * @param Title $nt The new page Title
3553          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3554          */
3555         public function moveNoAuth( &$nt ) {
3556                 return $this->moveTo( $nt, false );
3557         }
3558
3559         /**
3560          * Check whether a given move operation would be valid.
3561          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3562          *
3563          * @param Title $nt The new title
3564          * @param bool $auth Indicates whether $wgUser's permissions
3565          *  should be checked
3566          * @param string $reason Is the log summary of the move, used for spam checking
3567          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3568          */
3569         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3570                 global $wgUser, $wgContentHandlerUseDB;
3571
3572                 $errors = array();
3573                 if ( !$nt ) {
3574                         // Normally we'd add this to $errors, but we'll get
3575                         // lots of syntax errors if $nt is not an object
3576                         return array( array( 'badtitletext' ) );
3577                 }
3578                 if ( $this->equals( $nt ) ) {
3579                         $errors[] = array( 'selfmove' );
3580                 }
3581                 if ( !$this->isMovable() ) {
3582                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3583                 }
3584                 if ( $nt->isExternal() ) {
3585                         $errors[] = array( 'immobile-target-namespace-iw' );
3586                 }
3587                 if ( !$nt->isMovable() ) {
3588                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3589                 }
3590
3591                 $oldid = $this->getArticleID();
3592                 $newid = $nt->getArticleID();
3593
3594                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3595                         $errors[] = array( 'articleexists' );
3596                 }
3597                 if (
3598                         ( $this->getDBkey() == '' ) ||
3599                         ( !$oldid ) ||
3600                         ( $nt->getDBkey() == '' )
3601                 ) {
3602                         $errors[] = array( 'badarticleerror' );
3603                 }
3604
3605                 // Content model checks
3606                 if ( !$wgContentHandlerUseDB &&
3607                                 $this->getContentModel() !== $nt->getContentModel() ) {
3608                         // can't move a page if that would change the page's content model
3609                         $errors[] = array(
3610                                 'bad-target-model',
3611                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3612                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3613                         );
3614                 }
3615
3616                 // Image-specific checks
3617                 if ( $this->getNamespace() == NS_FILE ) {
3618                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3619                 }
3620
3621                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3622                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3623                 }
3624
3625                 if ( $auth ) {
3626                         $errors = wfMergeErrorArrays( $errors,
3627                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3628                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3629                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3630                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3631                 }
3632
3633                 $match = EditPage::matchSummarySpamRegex( $reason );
3634                 if ( $match !== false ) {
3635                         // This is kind of lame, won't display nice
3636                         $errors[] = array( 'spamprotectiontext' );
3637                 }
3638
3639                 $err = null;
3640                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3641                         $errors[] = array( 'hookaborted', $err );
3642                 }
3643
3644                 # The move is allowed only if (1) the target doesn't exist, or
3645                 # (2) the target is a redirect to the source, and has no history
3646                 # (so we can undo bad moves right after they're done).
3647
3648                 if ( 0 != $newid ) { # Target exists; check for validity
3649                         if ( !$this->isValidMoveTarget( $nt ) ) {
3650                                 $errors[] = array( 'articleexists' );
3651                         }
3652                 } else {
3653                         $tp = $nt->getTitleProtection();
3654                         $right = $tp['pt_create_perm'];
3655                         if ( $right == 'sysop' ) {
3656                                 $right = 'editprotected'; // B/C
3657                         }
3658                         if ( $right == 'autoconfirmed' ) {
3659                                 $right = 'editsemiprotected'; // B/C
3660                         }
3661                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3662                                 $errors[] = array( 'cantmove-titleprotected' );
3663                         }
3664                 }
3665                 if ( empty( $errors ) ) {
3666                         return true;
3667                 }
3668                 return $errors;
3669         }
3670
3671         /**
3672          * Check if the requested move target is a valid file move target
3673          * @param Title $nt Target title
3674          * @return array List of errors
3675          */
3676         protected function validateFileMoveOperation( $nt ) {
3677                 global $wgUser;
3678
3679                 $errors = array();
3680
3681                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3682
3683                 $file = wfLocalFile( $this );
3684                 if ( $file->exists() ) {
3685                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3686                                 $errors[] = array( 'imageinvalidfilename' );
3687                         }
3688                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3689                                 $errors[] = array( 'imagetypemismatch' );
3690                         }
3691                 }
3692
3693                 if ( $nt->getNamespace() != NS_FILE ) {
3694                         $errors[] = array( 'imagenocrossnamespace' );
3695                         // From here we want to do checks on a file object, so if we can't
3696                         // create one, we must return.
3697                         return $errors;
3698                 }
3699
3700                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3701
3702                 $destFile = wfLocalFile( $nt );
3703                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3704                         $errors[] = array( 'file-exists-sharedrepo' );
3705                 }
3706
3707                 return $errors;
3708         }
3709
3710         /**
3711          * Move a title to a new location
3712          *
3713          * @param Title $nt The new title
3714          * @param bool $auth Indicates whether $wgUser's permissions
3715          *  should be checked
3716          * @param string $reason The reason for the move
3717          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3718          *  Ignored if the user doesn't have the suppressredirect right.
3719          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3720          */
3721         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3722                 global $wgUser;
3723                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3724                 if ( is_array( $err ) ) {
3725                         // Auto-block user's IP if the account was "hard" blocked
3726                         $wgUser->spreadAnyEditBlock();
3727                         return $err;
3728                 }
3729                 // Check suppressredirect permission
3730                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3731                         $createRedirect = true;
3732                 }
3733
3734                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3735
3736                 // If it is a file, move it first.
3737                 // It is done before all other moving stuff is done because it's hard to revert.
3738                 $dbw = wfGetDB( DB_MASTER );
3739                 if ( $this->getNamespace() == NS_FILE ) {
3740                         $file = wfLocalFile( $this );
3741                         if ( $file->exists() ) {
3742                                 $status = $file->move( $nt );
3743                                 if ( !$status->isOk() ) {
3744                                         return $status->getErrorsArray();
3745                                 }
3746                         }
3747                         // Clear RepoGroup process cache
3748                         RepoGroup::singleton()->clearCache( $this );
3749                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3750                 }
3751
3752                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3753                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3754                 $protected = $this->isProtected();
3755
3756                 // Do the actual move
3757                 $this->moveToInternal( $nt, $reason, $createRedirect );
3758
3759                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3760                 // cl_timestamp, which may disturb time-based lists on some sites.
3761                 $prefixes = $dbw->select(
3762                         'categorylinks',
3763                         array( 'cl_sortkey_prefix', 'cl_to' ),
3764                         array( 'cl_from' => $pageid ),
3765                         __METHOD__
3766                 );
3767                 foreach ( $prefixes as $prefixRow ) {
3768                         $prefix = $prefixRow->cl_sortkey_prefix;
3769                         $catTo = $prefixRow->cl_to;
3770                         $dbw->update( 'categorylinks',
3771                                 array(
3772                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3773                                                 $nt->getCategorySortkey( $prefix ) ),
3774                                         'cl_timestamp=cl_timestamp' ),
3775                                 array(
3776                                         'cl_from' => $pageid,
3777                                         'cl_to' => $catTo ),
3778                                 __METHOD__
3779                         );
3780                 }
3781
3782                 $redirid = $this->getArticleID();
3783
3784                 if ( $protected ) {
3785                         # Protect the redirect title as the title used to be...
3786                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3787                                 array(
3788                                         'pr_page' => $redirid,
3789                                         'pr_type' => 'pr_type',
3790                                         'pr_level' => 'pr_level',
3791                                         'pr_cascade' => 'pr_cascade',
3792                                         'pr_user' => 'pr_user',
3793                                         'pr_expiry' => 'pr_expiry'
3794                                 ),
3795                                 array( 'pr_page' => $pageid ),
3796                                 __METHOD__,
3797                                 array( 'IGNORE' )
3798                         );
3799                         # Update the protection log
3800                         $log = new LogPage( 'protect' );
3801                         $comment = wfMessage(
3802                                 'prot_1movedto2',
3803                                 $this->getPrefixedText(),
3804                                 $nt->getPrefixedText()
3805                         )->inContentLanguage()->text();
3806                         if ( $reason ) {
3807                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3808                         }
3809                         // @todo FIXME: $params?
3810                         $logId = $log->addEntry(
3811                                 'move_prot',
3812                                 $nt,
3813                                 $comment,
3814                                 array( $this->getPrefixedText() ),
3815                                 $wgUser
3816                         );
3817
3818                         // reread inserted pr_ids for log relation
3819                         $insertedPrIds = $dbw->select(
3820                                 'page_restrictions',
3821                                 'pr_id',
3822                                 array( 'pr_page' => $redirid ),
3823                                 __METHOD__
3824                         );
3825                         $logRelationsValues = array();
3826                         foreach ( $insertedPrIds as $prid ) {
3827                                 $logRelationsValues[] = $prid->pr_id;
3828                         }
3829                         $log->addRelations( 'pr_id', $logRelationsValues, $logId );
3830                 }
3831
3832                 // Update *_from_namespace fields as needed
3833                 if ( $this->getNamespace() != $nt->getNamespace() ) {
3834                         $dbw->update( 'pagelinks',
3835                                 array( 'pl_from_namespace' => $nt->getNamespace() ),
3836                                 array( 'pl_from' => $pageid ),
3837                                 __METHOD__
3838                         );
3839                         $dbw->update( 'templatelinks',
3840                                 array( 'tl_from_namespace' => $nt->getNamespace() ),
3841                                 array( 'tl_from' => $pageid ),
3842                                 __METHOD__
3843                         );
3844                         $dbw->update( 'imagelinks',
3845                                 array( 'il_from_namespace' => $nt->getNamespace() ),
3846                                 array( 'il_from' => $pageid ),
3847                                 __METHOD__
3848                         );
3849                 }
3850
3851                 # Update watchlists
3852                 $oldtitle = $this->getDBkey();
3853                 $newtitle = $nt->getDBkey();
3854                 $oldsnamespace = MWNamespace::getSubject( $this->getNamespace() );
3855                 $newsnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3856                 if ( $oldsnamespace != $newsnamespace || $oldtitle != $newtitle ) {
3857                         WatchedItem::duplicateEntries( $this, $nt );
3858                 }
3859
3860                 $dbw->commit( __METHOD__ );
3861
3862                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid, $reason ) );
3863                 return true;
3864         }
3865
3866         /**
3867          * Move page to a title which is either a redirect to the
3868          * source page or nonexistent
3869          *
3870          * @param Title $nt The page to move to, which should be a redirect or nonexistent
3871          * @param string $reason The reason for the move
3872          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3873          *   if the user has the suppressredirect right
3874          * @throws MWException
3875          */
3876         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3877                 global $wgUser, $wgContLang;
3878
3879                 if ( $nt->exists() ) {
3880                         $moveOverRedirect = true;
3881                         $logType = 'move_redir';
3882                 } else {
3883                         $moveOverRedirect = false;
3884                         $logType = 'move';
3885                 }
3886
3887                 if ( $createRedirect ) {
3888                         if ( $this->getNamespace() == NS_CATEGORY
3889                                 && !wfMessage( 'category-move-redirect-override' )->inContentLanguage()->isDisabled()
3890                         ) {
3891                                 $redirectContent = new WikitextContent(
3892                                         wfMessage( 'category-move-redirect-override' )
3893                                                 ->params( $nt->getPrefixedText() )->inContentLanguage()->plain() );
3894                         } else {
3895                                 $contentHandler = ContentHandler::getForTitle( $this );
3896                                 $redirectContent = $contentHandler->makeRedirectContent( $nt,
3897                                         wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3898                         }
3899
3900                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3901                 } else {
3902                         $redirectContent = null;
3903                 }
3904
3905                 $logEntry = new ManualLogEntry( 'move', $logType );
3906                 $logEntry->setPerformer( $wgUser );
3907                 $logEntry->setTarget( $this );
3908                 $logEntry->setComment( $reason );
3909                 $logEntry->setParameters( array(
3910                         '4::target' => $nt->getPrefixedText(),
3911                         '5::noredir' => $redirectContent ? '0': '1',
3912                 ) );
3913
3914                 $formatter = LogFormatter::newFromEntry( $logEntry );
3915                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3916                 $comment = $formatter->getPlainActionText();
3917                 if ( $reason ) {
3918                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3919                 }
3920                 # Truncate for whole multibyte characters.
3921                 $comment = $wgContLang->truncate( $comment, 255 );
3922
3923                 $oldid = $this->getArticleID();
3924
3925                 $dbw = wfGetDB( DB_MASTER );
3926
3927                 $newpage = WikiPage::factory( $nt );
3928
3929                 if ( $moveOverRedirect ) {
3930                         $newid = $nt->getArticleID();
3931                         $newcontent = $newpage->getContent();
3932
3933                         # Delete the old redirect. We don't save it to history since
3934                         # by definition if we've got here it's rather uninteresting.
3935                         # We have to remove it so that the next step doesn't trigger
3936                         # a conflict on the unique namespace+title index...
3937                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3938
3939                         $newpage->doDeleteUpdates( $newid, $newcontent );
3940                 }
3941
3942                 # Save a null revision in the page's history notifying of the move
3943                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true, $wgUser );
3944                 if ( !is_object( $nullRevision ) ) {
3945                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3946                 }
3947
3948                 $nullRevision->insertOn( $dbw );
3949
3950                 # Change the name of the target page:
3951                 $dbw->update( 'page',
3952                         /* SET */ array(
3953                                 'page_namespace' => $nt->getNamespace(),
3954                                 'page_title' => $nt->getDBkey(),
3955                         ),
3956                         /* WHERE */ array( 'page_id' => $oldid ),
3957                         __METHOD__
3958                 );
3959
3960                 // clean up the old title before reset article id - bug 45348
3961                 if ( !$redirectContent ) {
3962                         WikiPage::onArticleDelete( $this );
3963                 }
3964
3965                 $this->resetArticleID( 0 ); // 0 == non existing
3966                 $nt->resetArticleID( $oldid );
3967                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
3968
3969                 $newpage->updateRevisionOn( $dbw, $nullRevision );
3970
3971                 wfRunHooks( 'NewRevisionFromEditComplete',
3972                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
3973
3974                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
3975
3976                 if ( !$moveOverRedirect ) {
3977                         WikiPage::onArticleCreate( $nt );
3978                 }
3979
3980                 # Recreate the redirect, this time in the other direction.
3981                 if ( $redirectContent ) {
3982                         $redirectArticle = WikiPage::factory( $this );
3983                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
3984                         $newid = $redirectArticle->insertOn( $dbw );
3985                         if ( $newid ) { // sanity
3986                                 $this->resetArticleID( $newid );
3987                                 $redirectRevision = new Revision( array(
3988                                         'title' => $this, // for determining the default content model
3989                                         'page' => $newid,
3990                                         'user_text' => $wgUser->getName(),
3991                                         'user' => $wgUser->getId(),
3992                                         'comment' => $comment,
3993                                         'content' => $redirectContent ) );
3994                                 $redirectRevision->insertOn( $dbw );
3995                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
3996
3997                                 wfRunHooks( 'NewRevisionFromEditComplete',
3998                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
3999
4000                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
4001                         }
4002                 }
4003
4004                 # Log the move
4005                 $logid = $logEntry->insert();
4006                 $logEntry->publish( $logid );
4007         }
4008
4009         /**
4010          * Move this page's subpages to be subpages of $nt
4011          *
4012          * @param Title $nt Move target
4013          * @param bool $auth Whether $wgUser's permissions should be checked
4014          * @param string $reason The reason for the move
4015          * @param bool $createRedirect Whether to create redirects from the old subpages to
4016          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4017          * @return array Array with old page titles as keys, and strings (new page titles) or
4018          *     arrays (errors) as values, or an error array with numeric indices if no pages
4019          *     were moved
4020          */
4021         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
4022                 global $wgMaximumMovedPages;
4023                 // Check permissions
4024                 if ( !$this->userCan( 'move-subpages' ) ) {
4025                         return array( 'cant-move-subpages' );
4026                 }
4027                 // Do the source and target namespaces support subpages?
4028                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4029                         return array( 'namespace-nosubpages',
4030                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
4031                 }
4032                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4033                         return array( 'namespace-nosubpages',
4034                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
4035                 }
4036
4037                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4038                 $retval = array();
4039                 $count = 0;
4040                 foreach ( $subpages as $oldSubpage ) {
4041                         $count++;
4042                         if ( $count > $wgMaximumMovedPages ) {
4043                                 $retval[$oldSubpage->getPrefixedText()] =
4044                                                 array( 'movepage-max-pages',
4045                                                         $wgMaximumMovedPages );
4046                                 break;
4047                         }
4048
4049                         // We don't know whether this function was called before
4050                         // or after moving the root page, so check both
4051                         // $this and $nt
4052                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4053                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4054                         ) {
4055                                 // When moving a page to a subpage of itself,
4056                                 // don't move it twice
4057                                 continue;
4058                         }
4059                         $newPageName = preg_replace(
4060                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4061                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4062                                         $oldSubpage->getDBkey() );
4063                         if ( $oldSubpage->isTalkPage() ) {
4064                                 $newNs = $nt->getTalkPage()->getNamespace();
4065                         } else {
4066                                 $newNs = $nt->getSubjectPage()->getNamespace();
4067                         }
4068                         # Bug 14385: we need makeTitleSafe because the new page names may
4069                         # be longer than 255 characters.
4070                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4071
4072                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4073                         if ( $success === true ) {
4074                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4075                         } else {
4076                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4077                         }
4078                 }
4079                 return $retval;
4080         }
4081
4082         /**
4083          * Checks if this page is just a one-rev redirect.
4084          * Adds lock, so don't use just for light purposes.
4085          *
4086          * @return bool
4087          */
4088         public function isSingleRevRedirect() {
4089                 global $wgContentHandlerUseDB;
4090
4091                 $dbw = wfGetDB( DB_MASTER );
4092
4093                 # Is it a redirect?
4094                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4095                 if ( $wgContentHandlerUseDB ) {
4096                         $fields[] = 'page_content_model';
4097                 }
4098
4099                 $row = $dbw->selectRow( 'page',
4100                         $fields,
4101                         $this->pageCond(),
4102                         __METHOD__,
4103                         array( 'FOR UPDATE' )
4104                 );
4105                 # Cache some fields we may want
4106                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4107                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4108                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4109                 $this->mContentModel = $row && isset( $row->page_content_model )
4110                         ? strval( $row->page_content_model )
4111                         : false;
4112
4113                 if ( !$this->mRedirect ) {
4114                         return false;
4115                 }
4116                 # Does the article have a history?
4117                 $row = $dbw->selectField( array( 'page', 'revision' ),
4118                         'rev_id',
4119                         array( 'page_namespace' => $this->getNamespace(),
4120                                 'page_title' => $this->getDBkey(),
4121                                 'page_id=rev_page',
4122                                 'page_latest != rev_id'
4123                         ),
4124                         __METHOD__,
4125                         array( 'FOR UPDATE' )
4126                 );
4127                 # Return true if there was no history
4128                 return ( $row === false );
4129         }
4130
4131         /**
4132          * Checks if $this can be moved to a given Title
4133          * - Selects for update, so don't call it unless you mean business
4134          *
4135          * @param Title $nt The new title to check
4136          * @return bool
4137          */
4138         public function isValidMoveTarget( $nt ) {
4139                 # Is it an existing file?
4140                 if ( $nt->getNamespace() == NS_FILE ) {
4141                         $file = wfLocalFile( $nt );
4142                         if ( $file->exists() ) {
4143                                 wfDebug( __METHOD__ . ": file exists\n" );
4144                                 return false;
4145                         }
4146                 }
4147                 # Is it a redirect with no history?
4148                 if ( !$nt->isSingleRevRedirect() ) {
4149                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4150                         return false;
4151                 }
4152                 # Get the article text
4153                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4154                 if ( !is_object( $rev ) ) {
4155                         return false;
4156                 }
4157                 $content = $rev->getContent();
4158                 # Does the redirect point to the source?
4159                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4160                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4161
4162                 if ( $redirTitle ) {
4163                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4164                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4165                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4166                                 return false;
4167                         } else {
4168                                 return true;
4169                         }
4170                 } else {
4171                         # Fail safe (not a redirect after all. strange.)
4172                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4173                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4174                         return false;
4175                 }
4176         }
4177
4178         /**
4179          * Get categories to which this Title belongs and return an array of
4180          * categories' names.
4181          *
4182          * @return array Array of parents in the form:
4183          *        $parent => $currentarticle
4184          */
4185         public function getParentCategories() {
4186                 global $wgContLang;
4187
4188                 $data = array();
4189
4190                 $titleKey = $this->getArticleID();
4191
4192                 if ( $titleKey === 0 ) {
4193                         return $data;
4194                 }
4195
4196                 $dbr = wfGetDB( DB_SLAVE );
4197
4198                 $res = $dbr->select(
4199                         'categorylinks',
4200                         'cl_to',
4201                         array( 'cl_from' => $titleKey ),
4202                         __METHOD__
4203                 );
4204
4205                 if ( $res->numRows() > 0 ) {
4206                         foreach ( $res as $row ) {
4207                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4208                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4209                         }
4210                 }
4211                 return $data;
4212         }
4213
4214         /**
4215          * Get a tree of parent categories
4216          *
4217          * @param array $children Array with the children in the keys, to check for circular refs
4218          * @return array Tree of parent categories
4219          */
4220         public function getParentCategoryTree( $children = array() ) {
4221                 $stack = array();
4222                 $parents = $this->getParentCategories();
4223
4224                 if ( $parents ) {
4225                         foreach ( $parents as $parent => $current ) {
4226                                 if ( array_key_exists( $parent, $children ) ) {
4227                                         # Circular reference
4228                                         $stack[$parent] = array();
4229                                 } else {
4230                                         $nt = Title::newFromText( $parent );
4231                                         if ( $nt ) {
4232                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4233                                         }
4234                                 }
4235                         }
4236                 }
4237
4238                 return $stack;
4239         }
4240
4241         /**
4242          * Get an associative array for selecting this title from
4243          * the "page" table
4244          *
4245          * @return array Array suitable for the $where parameter of DB::select()
4246          */
4247         public function pageCond() {
4248                 if ( $this->mArticleID > 0 ) {
4249                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4250                         return array( 'page_id' => $this->mArticleID );
4251                 } else {
4252                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4253                 }
4254         }
4255
4256         /**
4257          * Get the revision ID of the previous revision
4258          *
4259          * @param int $revId Revision ID. Get the revision that was before this one.
4260          * @param int $flags Title::GAID_FOR_UPDATE
4261          * @return int|bool Old revision ID, or false if none exists
4262          */
4263         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4264                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4265                 $revId = $db->selectField( 'revision', 'rev_id',
4266                         array(
4267                                 'rev_page' => $this->getArticleID( $flags ),
4268                                 'rev_id < ' . intval( $revId )
4269                         ),
4270                         __METHOD__,
4271                         array( 'ORDER BY' => 'rev_id DESC' )
4272                 );
4273
4274                 if ( $revId === false ) {
4275                         return false;
4276                 } else {
4277                         return intval( $revId );
4278                 }
4279         }
4280
4281         /**
4282          * Get the revision ID of the next revision
4283          *
4284          * @param int $revId Revision ID. Get the revision that was after this one.
4285          * @param int $flags Title::GAID_FOR_UPDATE
4286          * @return int|bool Next revision ID, or false if none exists
4287          */
4288         public function getNextRevisionID( $revId, $flags = 0 ) {
4289                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4290                 $revId = $db->selectField( 'revision', 'rev_id',
4291                         array(
4292                                 'rev_page' => $this->getArticleID( $flags ),
4293                                 'rev_id > ' . intval( $revId )
4294                         ),
4295                         __METHOD__,
4296                         array( 'ORDER BY' => 'rev_id' )
4297                 );
4298
4299                 if ( $revId === false ) {
4300                         return false;
4301                 } else {
4302                         return intval( $revId );
4303                 }
4304         }
4305
4306         /**
4307          * Get the first revision of the page
4308          *
4309          * @param int $flags Title::GAID_FOR_UPDATE
4310          * @return Revision|null If page doesn't exist
4311          */
4312         public function getFirstRevision( $flags = 0 ) {
4313                 $pageId = $this->getArticleID( $flags );
4314                 if ( $pageId ) {
4315                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4316                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4317                                 array( 'rev_page' => $pageId ),
4318                                 __METHOD__,
4319                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4320                         );
4321                         if ( $row ) {
4322                                 return new Revision( $row );
4323                         }
4324                 }
4325                 return null;
4326         }
4327
4328         /**
4329          * Get the oldest revision timestamp of this page
4330          *
4331          * @param int $flags Title::GAID_FOR_UPDATE
4332          * @return string MW timestamp
4333          */
4334         public function getEarliestRevTime( $flags = 0 ) {
4335                 $rev = $this->getFirstRevision( $flags );
4336                 return $rev ? $rev->getTimestamp() : null;
4337         }
4338
4339         /**
4340          * Check if this is a new page
4341          *
4342          * @return bool
4343          */
4344         public function isNewPage() {
4345                 $dbr = wfGetDB( DB_SLAVE );
4346                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4347         }
4348
4349         /**
4350          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4351          *
4352          * @return bool
4353          */
4354         public function isBigDeletion() {
4355                 global $wgDeleteRevisionsLimit;
4356
4357                 if ( !$wgDeleteRevisionsLimit ) {
4358                         return false;
4359                 }
4360
4361                 $revCount = $this->estimateRevisionCount();
4362                 return $revCount > $wgDeleteRevisionsLimit;
4363         }
4364
4365         /**
4366          * Get the  approximate revision count of this page.
4367          *
4368          * @return int
4369          */
4370         public function estimateRevisionCount() {
4371                 if ( !$this->exists() ) {
4372                         return 0;
4373                 }
4374
4375                 if ( $this->mEstimateRevisions === null ) {
4376                         $dbr = wfGetDB( DB_SLAVE );
4377                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4378                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4379                 }
4380
4381                 return $this->mEstimateRevisions;
4382         }
4383
4384         /**
4385          * Get the number of revisions between the given revision.
4386          * Used for diffs and other things that really need it.
4387          *
4388          * @param int|Revision $old Old revision or rev ID (first before range)
4389          * @param int|Revision $new New revision or rev ID (first after range)
4390          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4391          * @return int Number of revisions between these revisions.
4392          */
4393         public function countRevisionsBetween( $old, $new, $max = null ) {
4394                 if ( !( $old instanceof Revision ) ) {
4395                         $old = Revision::newFromTitle( $this, (int)$old );
4396                 }
4397                 if ( !( $new instanceof Revision ) ) {
4398                         $new = Revision::newFromTitle( $this, (int)$new );
4399                 }
4400                 if ( !$old || !$new ) {
4401                         return 0; // nothing to compare
4402                 }
4403                 $dbr = wfGetDB( DB_SLAVE );
4404                 $conds = array(
4405                         'rev_page' => $this->getArticleID(),
4406                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4407                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4408                 );
4409                 if ( $max !== null ) {
4410                         $res = $dbr->select( 'revision', '1',
4411                                 $conds,
4412                                 __METHOD__,
4413                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4414                         );
4415                         return $res->numRows();
4416                 } else {
4417                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4418                 }
4419         }
4420
4421         /**
4422          * Get the authors between the given revisions or revision IDs.
4423          * Used for diffs and other things that really need it.
4424          *
4425          * @since 1.23
4426          *
4427          * @param int|Revision $old Old revision or rev ID (first before range by default)
4428          * @param int|Revision $new New revision or rev ID (first after range by default)
4429          * @param int $limit Maximum number of authors
4430          * @param string|array $options (Optional): Single option, or an array of options:
4431          *     'include_old' Include $old in the range; $new is excluded.
4432          *     'include_new' Include $new in the range; $old is excluded.
4433          *     'include_both' Include both $old and $new in the range.
4434          *     Unknown option values are ignored.
4435          * @return array|null Names of revision authors in the range; null if not both revisions exist
4436          */
4437         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4438                 if ( !( $old instanceof Revision ) ) {
4439                         $old = Revision::newFromTitle( $this, (int)$old );
4440                 }
4441                 if ( !( $new instanceof Revision ) ) {
4442                         $new = Revision::newFromTitle( $this, (int)$new );
4443                 }
4444                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4445                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4446                 // in the sanity check below?
4447                 if ( !$old || !$new ) {
4448                         return null; // nothing to compare
4449                 }
4450                 $authors = array();
4451                 $old_cmp = '>';
4452                 $new_cmp = '<';
4453                 $options = (array)$options;
4454                 if ( in_array( 'include_old', $options ) ) {
4455                         $old_cmp = '>=';
4456                 }
4457                 if ( in_array( 'include_new', $options ) ) {
4458                         $new_cmp = '<=';
4459                 }
4460                 if ( in_array( 'include_both', $options ) ) {
4461                         $old_cmp = '>=';
4462                         $new_cmp = '<=';
4463                 }
4464                 // No DB query needed if $old and $new are the same or successive revisions:
4465                 if ( $old->getId() === $new->getId() ) {
4466                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? array() : array( $old->getRawUserText() );
4467                 } elseif ( $old->getId() === $new->getParentId() ) {
4468                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4469                                 $authors[] = $old->getRawUserText();
4470                                 if ( $old->getRawUserText() != $new->getRawUserText() ) {
4471                                         $authors[] = $new->getRawUserText();
4472                                 }
4473                         } elseif ( $old_cmp === '>=' ) {
4474                                 $authors[] = $old->getRawUserText();
4475                         } elseif ( $new_cmp === '<=' ) {
4476                                 $authors[] = $new->getRawUserText();
4477                         }
4478                         return $authors;
4479                 }
4480                 $dbr = wfGetDB( DB_SLAVE );
4481                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4482                         array(
4483                                 'rev_page' => $this->getArticleID(),
4484                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4485                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4486                         ), __METHOD__,
4487                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4488                 );
4489                 foreach ( $res as $row ) {
4490                         $authors[] = $row->rev_user_text;
4491                 }
4492                 return $authors;
4493         }
4494
4495         /**
4496          * Get the number of authors between the given revisions or revision IDs.
4497          * Used for diffs and other things that really need it.
4498          *
4499          * @param int|Revision $old Old revision or rev ID (first before range by default)
4500          * @param int|Revision $new New revision or rev ID (first after range by default)
4501          * @param int $limit Maximum number of authors
4502          * @param string|array $options (Optional): Single option, or an array of options:
4503          *     'include_old' Include $old in the range; $new is excluded.
4504          *     'include_new' Include $new in the range; $old is excluded.
4505          *     'include_both' Include both $old and $new in the range.
4506          *     Unknown option values are ignored.
4507          * @return int Number of revision authors in the range; zero if not both revisions exist
4508          */
4509         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4510                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4511                 return $authors ? count( $authors ) : 0;
4512         }
4513
4514         /**
4515          * Compare with another title.
4516          *
4517          * @param Title $title
4518          * @return bool
4519          */
4520         public function equals( Title $title ) {
4521                 // Note: === is necessary for proper matching of number-like titles.
4522                 return $this->getInterwiki() === $title->getInterwiki()
4523                         && $this->getNamespace() == $title->getNamespace()
4524                         && $this->getDBkey() === $title->getDBkey();
4525         }
4526
4527         /**
4528          * Check if this title is a subpage of another title
4529          *
4530          * @param Title $title
4531          * @return bool
4532          */
4533         public function isSubpageOf( Title $title ) {
4534                 return $this->getInterwiki() === $title->getInterwiki()
4535                         && $this->getNamespace() == $title->getNamespace()
4536                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4537         }
4538
4539         /**
4540          * Check if page exists.  For historical reasons, this function simply
4541          * checks for the existence of the title in the page table, and will
4542          * thus return false for interwiki links, special pages and the like.
4543          * If you want to know if a title can be meaningfully viewed, you should
4544          * probably call the isKnown() method instead.
4545          *
4546          * @return bool
4547          */
4548         public function exists() {
4549                 return $this->getArticleID() != 0;
4550         }
4551
4552         /**
4553          * Should links to this title be shown as potentially viewable (i.e. as
4554          * "bluelinks"), even if there's no record by this title in the page
4555          * table?
4556          *
4557          * This function is semi-deprecated for public use, as well as somewhat
4558          * misleadingly named.  You probably just want to call isKnown(), which
4559          * calls this function internally.
4560          *
4561          * (ISSUE: Most of these checks are cheap, but the file existence check
4562          * can potentially be quite expensive.  Including it here fixes a lot of
4563          * existing code, but we might want to add an optional parameter to skip
4564          * it and any other expensive checks.)
4565          *
4566          * @return bool
4567          */
4568         public function isAlwaysKnown() {
4569                 $isKnown = null;
4570
4571                 /**
4572                  * Allows overriding default behavior for determining if a page exists.
4573                  * If $isKnown is kept as null, regular checks happen. If it's
4574                  * a boolean, this value is returned by the isKnown method.
4575                  *
4576                  * @since 1.20
4577                  *
4578                  * @param Title $title
4579                  * @param bool|null $isKnown
4580                  */
4581                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4582
4583                 if ( !is_null( $isKnown ) ) {
4584                         return $isKnown;
4585                 }
4586
4587                 if ( $this->isExternal() ) {
4588                         return true;  // any interwiki link might be viewable, for all we know
4589                 }
4590
4591                 switch ( $this->mNamespace ) {
4592                         case NS_MEDIA:
4593                         case NS_FILE:
4594                                 // file exists, possibly in a foreign repo
4595                                 return (bool)wfFindFile( $this );
4596                         case NS_SPECIAL:
4597                                 // valid special page
4598                                 return SpecialPageFactory::exists( $this->getDBkey() );
4599                         case NS_MAIN:
4600                                 // selflink, possibly with fragment
4601                                 return $this->mDbkeyform == '';
4602                         case NS_MEDIAWIKI:
4603                                 // known system message
4604                                 return $this->hasSourceText() !== false;
4605                         default:
4606                                 return false;
4607                 }
4608         }
4609
4610         /**
4611          * Does this title refer to a page that can (or might) be meaningfully
4612          * viewed?  In particular, this function may be used to determine if
4613          * links to the title should be rendered as "bluelinks" (as opposed to
4614          * "redlinks" to non-existent pages).
4615          * Adding something else to this function will cause inconsistency
4616          * since LinkHolderArray calls isAlwaysKnown() and does its own
4617          * page existence check.
4618          *
4619          * @return bool
4620          */
4621         public function isKnown() {
4622                 return $this->isAlwaysKnown() || $this->exists();
4623         }
4624
4625         /**
4626          * Does this page have source text?
4627          *
4628          * @return bool
4629          */
4630         public function hasSourceText() {
4631                 if ( $this->exists() ) {
4632                         return true;
4633                 }
4634
4635                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4636                         // If the page doesn't exist but is a known system message, default
4637                         // message content will be displayed, same for language subpages-
4638                         // Use always content language to avoid loading hundreds of languages
4639                         // to get the link color.
4640                         global $wgContLang;
4641                         list( $name, ) = MessageCache::singleton()->figureMessage(
4642                                 $wgContLang->lcfirst( $this->getText() )
4643                         );
4644                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4645                         return $message->exists();
4646                 }
4647
4648                 return false;
4649         }
4650
4651         /**
4652          * Get the default message text or false if the message doesn't exist
4653          *
4654          * @return string|bool
4655          */
4656         public function getDefaultMessageText() {
4657                 global $wgContLang;
4658
4659                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4660                         return false;
4661                 }
4662
4663                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4664                         $wgContLang->lcfirst( $this->getText() )
4665                 );
4666                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4667
4668                 if ( $message->exists() ) {
4669                         return $message->plain();
4670                 } else {
4671                         return false;
4672                 }
4673         }
4674
4675         /**
4676          * Updates page_touched for this page; called from LinksUpdate.php
4677          *
4678          * @return bool True if the update succeeded
4679          */
4680         public function invalidateCache() {
4681                 if ( wfReadOnly() ) {
4682                         return false;
4683                 }
4684
4685                 if ( $this->mArticleID === 0 ) {
4686                         return true; // avoid gap locking if we know it's not there
4687                 }
4688
4689                 $method = __METHOD__;
4690                 $dbw = wfGetDB( DB_MASTER );
4691                 $conds = $this->pageCond();
4692                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method ) {
4693                         $dbw->update(
4694                                 'page',
4695                                 array( 'page_touched' => $dbw->timestamp() ),
4696                                 $conds,
4697                                 $method
4698                         );
4699                 } );
4700
4701                 return true;
4702         }
4703
4704         /**
4705          * Update page_touched timestamps and send squid purge messages for
4706          * pages linking to this title. May be sent to the job queue depending
4707          * on the number of links. Typically called on create and delete.
4708          */
4709         public function touchLinks() {
4710                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4711                 $u->doUpdate();
4712
4713                 if ( $this->getNamespace() == NS_CATEGORY ) {
4714                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4715                         $u->doUpdate();
4716                 }
4717         }
4718
4719         /**
4720          * Get the last touched timestamp
4721          *
4722          * @param DatabaseBase $db Optional db
4723          * @return string Last-touched timestamp
4724          */
4725         public function getTouched( $db = null ) {
4726                 if ( $db === null ) {
4727                         $db = wfGetDB( DB_SLAVE );
4728                 }
4729                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4730                 return $touched;
4731         }
4732
4733         /**
4734          * Get the timestamp when this page was updated since the user last saw it.
4735          *
4736          * @param User $user
4737          * @return string|null
4738          */
4739         public function getNotificationTimestamp( $user = null ) {
4740                 global $wgUser, $wgShowUpdatedMarker;
4741                 // Assume current user if none given
4742                 if ( !$user ) {
4743                         $user = $wgUser;
4744                 }
4745                 // Check cache first
4746                 $uid = $user->getId();
4747                 // avoid isset here, as it'll return false for null entries
4748                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4749                         return $this->mNotificationTimestamp[$uid];
4750                 }
4751                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4752                         $this->mNotificationTimestamp[$uid] = false;
4753                         return $this->mNotificationTimestamp[$uid];
4754                 }
4755                 // Don't cache too much!
4756                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4757                         $this->mNotificationTimestamp = array();
4758                 }
4759                 $dbr = wfGetDB( DB_SLAVE );
4760                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4761                         'wl_notificationtimestamp',
4762                         array(
4763                                 'wl_user' => $user->getId(),
4764                                 'wl_namespace' => $this->getNamespace(),
4765                                 'wl_title' => $this->getDBkey(),
4766                         ),
4767                         __METHOD__
4768                 );
4769                 return $this->mNotificationTimestamp[$uid];
4770         }
4771
4772         /**
4773          * Generate strings used for xml 'id' names in monobook tabs
4774          *
4775          * @param string $prepend Defaults to 'nstab-'
4776          * @return string XML 'id' name
4777          */
4778         public function getNamespaceKey( $prepend = 'nstab-' ) {
4779                 global $wgContLang;
4780                 // Gets the subject namespace if this title
4781                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4782                 // Checks if canonical namespace name exists for namespace
4783                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4784                         // Uses canonical namespace name
4785                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4786                 } else {
4787                         // Uses text of namespace
4788                         $namespaceKey = $this->getSubjectNsText();
4789                 }
4790                 // Makes namespace key lowercase
4791                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4792                 // Uses main
4793                 if ( $namespaceKey == '' ) {
4794                         $namespaceKey = 'main';
4795                 }
4796                 // Changes file to image for backwards compatibility
4797                 if ( $namespaceKey == 'file' ) {
4798                         $namespaceKey = 'image';
4799                 }
4800                 return $prepend . $namespaceKey;
4801         }
4802
4803         /**
4804          * Get all extant redirects to this Title
4805          *
4806          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4807          * @return Title[] Array of Title redirects to this title
4808          */
4809         public function getRedirectsHere( $ns = null ) {
4810                 $redirs = array();
4811
4812                 $dbr = wfGetDB( DB_SLAVE );
4813                 $where = array(
4814                         'rd_namespace' => $this->getNamespace(),
4815                         'rd_title' => $this->getDBkey(),
4816                         'rd_from = page_id'
4817                 );
4818                 if ( $this->isExternal() ) {
4819                         $where['rd_interwiki'] = $this->getInterwiki();
4820                 } else {
4821                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4822                 }
4823                 if ( !is_null( $ns ) ) {
4824                         $where['page_namespace'] = $ns;
4825                 }
4826
4827                 $res = $dbr->select(
4828                         array( 'redirect', 'page' ),
4829                         array( 'page_namespace', 'page_title' ),
4830                         $where,
4831                         __METHOD__
4832                 );
4833
4834                 foreach ( $res as $row ) {
4835                         $redirs[] = self::newFromRow( $row );
4836                 }
4837                 return $redirs;
4838         }
4839
4840         /**
4841          * Check if this Title is a valid redirect target
4842          *
4843          * @return bool
4844          */
4845         public function isValidRedirectTarget() {
4846                 global $wgInvalidRedirectTargets;
4847
4848                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4849                 if ( $this->isSpecial( 'Userlogout' ) ) {
4850                         return false;
4851                 }
4852
4853                 foreach ( $wgInvalidRedirectTargets as $target ) {
4854                         if ( $this->isSpecial( $target ) ) {
4855                                 return false;
4856                         }
4857                 }
4858
4859                 return true;
4860         }
4861
4862         /**
4863          * Get a backlink cache object
4864          *
4865          * @return BacklinkCache
4866          */
4867         public function getBacklinkCache() {
4868                 return BacklinkCache::get( $this );
4869         }
4870
4871         /**
4872          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4873          *
4874          * @return bool
4875          */
4876         public function canUseNoindex() {
4877                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4878
4879                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4880                         ? $wgContentNamespaces
4881                         : $wgExemptFromUserRobotsControl;
4882
4883                 return !in_array( $this->mNamespace, $bannedNamespaces );
4884
4885         }
4886
4887         /**
4888          * Returns the raw sort key to be used for categories, with the specified
4889          * prefix.  This will be fed to Collation::getSortKey() to get a
4890          * binary sortkey that can be used for actual sorting.
4891          *
4892          * @param string $prefix The prefix to be used, specified using
4893          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4894          *   prefix.
4895          * @return string
4896          */
4897         public function getCategorySortkey( $prefix = '' ) {
4898                 $unprefixed = $this->getText();
4899
4900                 // Anything that uses this hook should only depend
4901                 // on the Title object passed in, and should probably
4902                 // tell the users to run updateCollations.php --force
4903                 // in order to re-sort existing category relations.
4904                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4905                 if ( $prefix !== '' ) {
4906                         # Separate with a line feed, so the unprefixed part is only used as
4907                         # a tiebreaker when two pages have the exact same prefix.
4908                         # In UCA, tab is the only character that can sort above LF
4909                         # so we strip both of them from the original prefix.
4910                         $prefix = strtr( $prefix, "\n\t", '  ' );
4911                         return "$prefix\n$unprefixed";
4912                 }
4913                 return $unprefixed;
4914         }
4915
4916         /**
4917          * Get the language in which the content of this page is written in
4918          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4919          * e.g. $wgLang (such as special pages, which are in the user language).
4920          *
4921          * @since 1.18
4922          * @return Language
4923          */
4924         public function getPageLanguage() {
4925                 global $wgLang, $wgLanguageCode;
4926                 wfProfileIn( __METHOD__ );
4927                 if ( $this->isSpecialPage() ) {
4928                         // special pages are in the user language
4929                         wfProfileOut( __METHOD__ );
4930                         return $wgLang;
4931                 }
4932
4933                 // Checking if DB language is set
4934                 if ( $this->mDbPageLanguage ) {
4935                         wfProfileOut( __METHOD__ );
4936                         return wfGetLangObj( $this->mDbPageLanguage );
4937                 }
4938
4939                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4940                         // Note that this may depend on user settings, so the cache should
4941                         // be only per-request.
4942                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4943                         // content to determine the page language!
4944                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4945                         // tests.
4946                         $contentHandler = ContentHandler::getForTitle( $this );
4947                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4948                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4949                 } else {
4950                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4951                 }
4952
4953                 wfProfileOut( __METHOD__ );
4954                 return $langObj;
4955         }
4956
4957         /**
4958          * Get the language in which the content of this page is written when
4959          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4960          * e.g. $wgLang (such as special pages, which are in the user language).
4961          *
4962          * @since 1.20
4963          * @return Language
4964          */
4965         public function getPageViewLanguage() {
4966                 global $wgLang;
4967
4968                 if ( $this->isSpecialPage() ) {
4969                         // If the user chooses a variant, the content is actually
4970                         // in a language whose code is the variant code.
4971                         $variant = $wgLang->getPreferredVariant();
4972                         if ( $wgLang->getCode() !== $variant ) {
4973                                 return Language::factory( $variant );
4974                         }
4975
4976                         return $wgLang;
4977                 }
4978
4979                 // @note Can't be cached persistently, depends on user settings.
4980                 // @note ContentHandler::getPageViewLanguage() may need to load the
4981                 //   content to determine the page language!
4982                 $contentHandler = ContentHandler::getForTitle( $this );
4983                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4984                 return $pageLang;
4985         }
4986
4987         /**
4988          * Get a list of rendered edit notices for this page.
4989          *
4990          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4991          * they will already be wrapped in paragraphs.
4992          *
4993          * @since 1.21
4994          * @param int $oldid Revision ID that's being edited
4995          * @return array
4996          */
4997         public function getEditNotices( $oldid = 0 ) {
4998                 $notices = array();
4999
5000                 # Optional notices on a per-namespace and per-page basis
5001                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
5002                 $editnotice_ns_message = wfMessage( $editnotice_ns );
5003                 if ( $editnotice_ns_message->exists() ) {
5004                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
5005                 }
5006                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
5007                         $parts = explode( '/', $this->getDBkey() );
5008                         $editnotice_base = $editnotice_ns;
5009                         while ( count( $parts ) > 0 ) {
5010                                 $editnotice_base .= '-' . array_shift( $parts );
5011                                 $editnotice_base_msg = wfMessage( $editnotice_base );
5012                                 if ( $editnotice_base_msg->exists() ) {
5013                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
5014                                 }
5015                         }
5016                 } else {
5017                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
5018                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
5019                         $editnoticeMsg = wfMessage( $editnoticeText );
5020                         if ( $editnoticeMsg->exists() ) {
5021                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
5022                         }
5023                 }
5024
5025                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
5026                 return $notices;
5027         }
5028 }