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                         $tempErrors = $this->checkPageRestrictions( 'edit',
2262                                 $user, array(), $doExpensiveQueries, true );
2263                         if( !$tempErrors ) {
2264                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2265                                         $user, $tempErrors, $doExpensiveQueries, true );
2266                         }
2267                         if ( $tempErrors ) {
2268                                 // If protection keeps them from editing, they shouldn't be able to delete.
2269                                 $errors[] = array( 'deleteprotected' );
2270                         }
2271                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2272                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2273                         ) {
2274                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2275                         }
2276                 }
2277                 return $errors;
2278         }
2279
2280         /**
2281          * Check that the user isn't blocked from editing.
2282          *
2283          * @param string $action The action to check
2284          * @param User $user User to check
2285          * @param array $errors List of current errors
2286          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2287          * @param bool $short Short circuit on first error
2288          *
2289          * @return array List of errors
2290          */
2291         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2292                 // Account creation blocks handled at userlogin.
2293                 // Unblocking handled in SpecialUnblock
2294                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2295                         return $errors;
2296                 }
2297
2298                 global $wgEmailConfirmToEdit;
2299
2300                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2301                         $errors[] = array( 'confirmedittext' );
2302                 }
2303
2304                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2305                         // Don't block the user from editing their own talk page unless they've been
2306                         // explicitly blocked from that too.
2307                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2308                         // @todo FIXME: Pass the relevant context into this function.
2309                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2310                 }
2311
2312                 return $errors;
2313         }
2314
2315         /**
2316          * Check that the user is allowed to read this page.
2317          *
2318          * @param string $action The action to check
2319          * @param User $user User to check
2320          * @param array $errors List of current errors
2321          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2322          * @param bool $short Short circuit on first error
2323          *
2324          * @return array List of errors
2325          */
2326         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2327                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2328
2329                 $whitelisted = false;
2330                 if ( User::isEveryoneAllowed( 'read' ) ) {
2331                         # Shortcut for public wikis, allows skipping quite a bit of code
2332                         $whitelisted = true;
2333                 } elseif ( $user->isAllowed( 'read' ) ) {
2334                         # If the user is allowed to read pages, he is allowed to read all pages
2335                         $whitelisted = true;
2336                 } elseif ( $this->isSpecial( 'Userlogin' )
2337                         || $this->isSpecial( 'ChangePassword' )
2338                         || $this->isSpecial( 'PasswordReset' )
2339                 ) {
2340                         # Always grant access to the login page.
2341                         # Even anons need to be able to log in.
2342                         $whitelisted = true;
2343                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2344                         # Time to check the whitelist
2345                         # Only do these checks is there's something to check against
2346                         $name = $this->getPrefixedText();
2347                         $dbName = $this->getPrefixedDBkey();
2348
2349                         // Check for explicit whitelisting with and without underscores
2350                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2351                                 $whitelisted = true;
2352                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2353                                 # Old settings might have the title prefixed with
2354                                 # a colon for main-namespace pages
2355                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2356                                         $whitelisted = true;
2357                                 }
2358                         } elseif ( $this->isSpecialPage() ) {
2359                                 # If it's a special page, ditch the subpage bit and check again
2360                                 $name = $this->getDBkey();
2361                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2362                                 if ( $name ) {
2363                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2364                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2365                                                 $whitelisted = true;
2366                                         }
2367                                 }
2368                         }
2369                 }
2370
2371                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2372                         $name = $this->getPrefixedText();
2373                         // Check for regex whitelisting
2374                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2375                                 if ( preg_match( $listItem, $name ) ) {
2376                                         $whitelisted = true;
2377                                         break;
2378                                 }
2379                         }
2380                 }
2381
2382                 if ( !$whitelisted ) {
2383                         # If the title is not whitelisted, give extensions a chance to do so...
2384                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2385                         if ( !$whitelisted ) {
2386                                 $errors[] = $this->missingPermissionError( $action, $short );
2387                         }
2388                 }
2389
2390                 return $errors;
2391         }
2392
2393         /**
2394          * Get a description array when the user doesn't have the right to perform
2395          * $action (i.e. when User::isAllowed() returns false)
2396          *
2397          * @param string $action The action to check
2398          * @param bool $short Short circuit on first error
2399          * @return array List of errors
2400          */
2401         private function missingPermissionError( $action, $short ) {
2402                 // We avoid expensive display logic for quickUserCan's and such
2403                 if ( $short ) {
2404                         return array( 'badaccess-group0' );
2405                 }
2406
2407                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2408                         User::getGroupsWithPermission( $action ) );
2409
2410                 if ( count( $groups ) ) {
2411                         global $wgLang;
2412                         return array(
2413                                 'badaccess-groups',
2414                                 $wgLang->commaList( $groups ),
2415                                 count( $groups )
2416                         );
2417                 } else {
2418                         return array( 'badaccess-group0' );
2419                 }
2420         }
2421
2422         /**
2423          * Can $user perform $action on this page? This is an internal function,
2424          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2425          * checks on wfReadOnly() and blocks)
2426          *
2427          * @param string $action Action that permission needs to be checked for
2428          * @param User $user User to check
2429          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2430          * @param bool $short Set this to true to stop after the first permission error.
2431          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2432          */
2433         protected function getUserPermissionsErrorsInternal( $action, $user,
2434                 $doExpensiveQueries = true, $short = false
2435         ) {
2436                 wfProfileIn( __METHOD__ );
2437
2438                 # Read has special handling
2439                 if ( $action == 'read' ) {
2440                         $checks = array(
2441                                 'checkPermissionHooks',
2442                                 'checkReadPermissions',
2443                         );
2444                 } else {
2445                         $checks = array(
2446                                 'checkQuickPermissions',
2447                                 'checkPermissionHooks',
2448                                 'checkSpecialsAndNSPermissions',
2449                                 'checkCSSandJSPermissions',
2450                                 'checkPageRestrictions',
2451                                 'checkCascadingSourcesRestrictions',
2452                                 'checkActionPermissions',
2453                                 'checkUserBlock'
2454                         );
2455                 }
2456
2457                 $errors = array();
2458                 while ( count( $checks ) > 0 &&
2459                                 !( $short && count( $errors ) > 0 ) ) {
2460                         $method = array_shift( $checks );
2461                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2462                 }
2463
2464                 wfProfileOut( __METHOD__ );
2465                 return $errors;
2466         }
2467
2468         /**
2469          * Get a filtered list of all restriction types supported by this wiki.
2470          * @param bool $exists True to get all restriction types that apply to
2471          * titles that do exist, False for all restriction types that apply to
2472          * titles that do not exist
2473          * @return array
2474          */
2475         public static function getFilteredRestrictionTypes( $exists = true ) {
2476                 global $wgRestrictionTypes;
2477                 $types = $wgRestrictionTypes;
2478                 if ( $exists ) {
2479                         # Remove the create restriction for existing titles
2480                         $types = array_diff( $types, array( 'create' ) );
2481                 } else {
2482                         # Only the create and upload restrictions apply to non-existing titles
2483                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2484                 }
2485                 return $types;
2486         }
2487
2488         /**
2489          * Returns restriction types for the current Title
2490          *
2491          * @return array Applicable restriction types
2492          */
2493         public function getRestrictionTypes() {
2494                 if ( $this->isSpecialPage() ) {
2495                         return array();
2496                 }
2497
2498                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2499
2500                 if ( $this->getNamespace() != NS_FILE ) {
2501                         # Remove the upload restriction for non-file titles
2502                         $types = array_diff( $types, array( 'upload' ) );
2503                 }
2504
2505                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2506
2507                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2508                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2509
2510                 return $types;
2511         }
2512
2513         /**
2514          * Is this title subject to title protection?
2515          * Title protection is the one applied against creation of such title.
2516          *
2517          * @return array|bool An associative array representing any existent title
2518          *   protection, or false if there's none.
2519          */
2520         private function getTitleProtection() {
2521                 // Can't protect pages in special namespaces
2522                 if ( $this->getNamespace() < 0 ) {
2523                         return false;
2524                 }
2525
2526                 // Can't protect pages that exist.
2527                 if ( $this->exists() ) {
2528                         return false;
2529                 }
2530
2531                 if ( $this->mTitleProtection === null ) {
2532                         $dbr = wfGetDB( DB_SLAVE );
2533                         $res = $dbr->select(
2534                                 'protected_titles',
2535                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2536                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2537                                 __METHOD__
2538                         );
2539
2540                         // fetchRow returns false if there are no rows.
2541                         $this->mTitleProtection = $dbr->fetchRow( $res );
2542                 }
2543                 return $this->mTitleProtection;
2544         }
2545
2546         /**
2547          * Remove any title protection due to page existing
2548          */
2549         public function deleteTitleProtection() {
2550                 $dbw = wfGetDB( DB_MASTER );
2551
2552                 $dbw->delete(
2553                         'protected_titles',
2554                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2555                         __METHOD__
2556                 );
2557                 $this->mTitleProtection = false;
2558         }
2559
2560         /**
2561          * Is this page "semi-protected" - the *only* protection levels are listed
2562          * in $wgSemiprotectedRestrictionLevels?
2563          *
2564          * @param string $action Action to check (default: edit)
2565          * @return bool
2566          */
2567         public function isSemiProtected( $action = 'edit' ) {
2568                 global $wgSemiprotectedRestrictionLevels;
2569
2570                 $restrictions = $this->getRestrictions( $action );
2571                 $semi = $wgSemiprotectedRestrictionLevels;
2572                 if ( !$restrictions || !$semi ) {
2573                         // Not protected, or all protection is full protection
2574                         return false;
2575                 }
2576
2577                 // Remap autoconfirmed to editsemiprotected for BC
2578                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2579                         $semi[$key] = 'editsemiprotected';
2580                 }
2581                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2582                         $restrictions[$key] = 'editsemiprotected';
2583                 }
2584
2585                 return !array_diff( $restrictions, $semi );
2586         }
2587
2588         /**
2589          * Does the title correspond to a protected article?
2590          *
2591          * @param string $action The action the page is protected from,
2592          * by default checks all actions.
2593          * @return bool
2594          */
2595         public function isProtected( $action = '' ) {
2596                 global $wgRestrictionLevels;
2597
2598                 $restrictionTypes = $this->getRestrictionTypes();
2599
2600                 # Special pages have inherent protection
2601                 if ( $this->isSpecialPage() ) {
2602                         return true;
2603                 }
2604
2605                 # Check regular protection levels
2606                 foreach ( $restrictionTypes as $type ) {
2607                         if ( $action == $type || $action == '' ) {
2608                                 $r = $this->getRestrictions( $type );
2609                                 foreach ( $wgRestrictionLevels as $level ) {
2610                                         if ( in_array( $level, $r ) && $level != '' ) {
2611                                                 return true;
2612                                         }
2613                                 }
2614                         }
2615                 }
2616
2617                 return false;
2618         }
2619
2620         /**
2621          * Determines if $user is unable to edit this page because it has been protected
2622          * by $wgNamespaceProtection.
2623          *
2624          * @param User $user User object to check permissions
2625          * @return bool
2626          */
2627         public function isNamespaceProtected( User $user ) {
2628                 global $wgNamespaceProtection;
2629
2630                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2631                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2632                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2633                                         return true;
2634                                 }
2635                         }
2636                 }
2637                 return false;
2638         }
2639
2640         /**
2641          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2642          *
2643          * @return bool If the page is subject to cascading restrictions.
2644          */
2645         public function isCascadeProtected() {
2646                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2647                 return ( $sources > 0 );
2648         }
2649
2650         /**
2651          * Determines whether cascading protection sources have already been loaded from
2652          * the database.
2653          *
2654          * @param bool $getPages True to check if the pages are loaded, or false to check
2655          * if the status is loaded.
2656          * @return bool Whether or not the specified information has been loaded
2657          * @since 1.23
2658          */
2659         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2660                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2661         }
2662
2663         /**
2664          * Cascading protection: Get the source of any cascading restrictions on this page.
2665          *
2666          * @param bool $getPages Whether or not to retrieve the actual pages
2667          *        that the restrictions have come from and the actual restrictions
2668          *        themselves.
2669          * @return array Two elements: First is an array of Title objects of the
2670          *        pages from which cascading restrictions have come, false for
2671          *        none, or true if such restrictions exist but $getPages was not
2672          *        set. Second is an array like that returned by
2673          *        Title::getAllRestrictions(), or an empty array if $getPages is
2674          *        false.
2675          */
2676         public function getCascadeProtectionSources( $getPages = true ) {
2677                 global $wgContLang;
2678                 $pagerestrictions = array();
2679
2680                 if ( $this->mCascadeSources !== null && $getPages ) {
2681                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2682                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2683                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2684                 }
2685
2686                 wfProfileIn( __METHOD__ );
2687
2688                 $dbr = wfGetDB( DB_SLAVE );
2689
2690                 if ( $this->getNamespace() == NS_FILE ) {
2691                         $tables = array( 'imagelinks', 'page_restrictions' );
2692                         $where_clauses = array(
2693                                 'il_to' => $this->getDBkey(),
2694                                 'il_from=pr_page',
2695                                 'pr_cascade' => 1
2696                         );
2697                 } else {
2698                         $tables = array( 'templatelinks', 'page_restrictions' );
2699                         $where_clauses = array(
2700                                 'tl_namespace' => $this->getNamespace(),
2701                                 'tl_title' => $this->getDBkey(),
2702                                 'tl_from=pr_page',
2703                                 'pr_cascade' => 1
2704                         );
2705                 }
2706
2707                 if ( $getPages ) {
2708                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2709                                 'pr_expiry', 'pr_type', 'pr_level' );
2710                         $where_clauses[] = 'page_id=pr_page';
2711                         $tables[] = 'page';
2712                 } else {
2713                         $cols = array( 'pr_expiry' );
2714                 }
2715
2716                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2717
2718                 $sources = $getPages ? array() : false;
2719                 $now = wfTimestampNow();
2720                 $purgeExpired = false;
2721
2722                 foreach ( $res as $row ) {
2723                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2724                         if ( $expiry > $now ) {
2725                                 if ( $getPages ) {
2726                                         $page_id = $row->pr_page;
2727                                         $page_ns = $row->page_namespace;
2728                                         $page_title = $row->page_title;
2729                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2730                                         # Add groups needed for each restriction type if its not already there
2731                                         # Make sure this restriction type still exists
2732
2733                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2734                                                 $pagerestrictions[$row->pr_type] = array();
2735                                         }
2736
2737                                         if (
2738                                                 isset( $pagerestrictions[$row->pr_type] )
2739                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2740                                         ) {
2741                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2742                                         }
2743                                 } else {
2744                                         $sources = true;
2745                                 }
2746                         } else {
2747                                 // Trigger lazy purge of expired restrictions from the db
2748                                 $purgeExpired = true;
2749                         }
2750                 }
2751                 if ( $purgeExpired ) {
2752                         Title::purgeExpiredRestrictions();
2753                 }
2754
2755                 if ( $getPages ) {
2756                         $this->mCascadeSources = $sources;
2757                         $this->mCascadingRestrictions = $pagerestrictions;
2758                 } else {
2759                         $this->mHasCascadingRestrictions = $sources;
2760                 }
2761
2762                 wfProfileOut( __METHOD__ );
2763                 return array( $sources, $pagerestrictions );
2764         }
2765
2766         /**
2767          * Accessor for mRestrictionsLoaded
2768          *
2769          * @return bool Whether or not the page's restrictions have already been
2770          * loaded from the database
2771          * @since 1.23
2772          */
2773         public function areRestrictionsLoaded() {
2774                 return $this->mRestrictionsLoaded;
2775         }
2776
2777         /**
2778          * Accessor/initialisation for mRestrictions
2779          *
2780          * @param string $action Action that permission needs to be checked for
2781          * @return array Restriction levels needed to take the action. All levels
2782          *     are required.
2783          */
2784         public function getRestrictions( $action ) {
2785                 if ( !$this->mRestrictionsLoaded ) {
2786                         $this->loadRestrictions();
2787                 }
2788                 return isset( $this->mRestrictions[$action] )
2789                                 ? $this->mRestrictions[$action]
2790                                 : array();
2791         }
2792
2793         /**
2794          * Accessor/initialisation for mRestrictions
2795          *
2796          * @return array Keys are actions, values are arrays as returned by
2797          *     Title::getRestrictions()
2798          * @since 1.23
2799          */
2800         public function getAllRestrictions() {
2801                 if ( !$this->mRestrictionsLoaded ) {
2802                         $this->loadRestrictions();
2803                 }
2804                 return $this->mRestrictions;
2805         }
2806
2807         /**
2808          * Get the expiry time for the restriction against a given action
2809          *
2810          * @param string $action
2811          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2812          *     or not protected at all, or false if the action is not recognised.
2813          */
2814         public function getRestrictionExpiry( $action ) {
2815                 if ( !$this->mRestrictionsLoaded ) {
2816                         $this->loadRestrictions();
2817                 }
2818                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2819         }
2820
2821         /**
2822          * Returns cascading restrictions for the current article
2823          *
2824          * @return bool
2825          */
2826         function areRestrictionsCascading() {
2827                 if ( !$this->mRestrictionsLoaded ) {
2828                         $this->loadRestrictions();
2829                 }
2830
2831                 return $this->mCascadeRestriction;
2832         }
2833
2834         /**
2835          * Loads a string into mRestrictions array
2836          *
2837          * @param ResultWrapper $res Resource restrictions as an SQL result.
2838          * @param string $oldFashionedRestrictions Comma-separated list of page
2839          *        restrictions from page table (pre 1.10)
2840          */
2841         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2842                 $rows = array();
2843
2844                 foreach ( $res as $row ) {
2845                         $rows[] = $row;
2846                 }
2847
2848                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2849         }
2850
2851         /**
2852          * Compiles list of active page restrictions from both page table (pre 1.10)
2853          * and page_restrictions table for this existing page.
2854          * Public for usage by LiquidThreads.
2855          *
2856          * @param array $rows Array of db result objects
2857          * @param string $oldFashionedRestrictions Comma-separated list of page
2858          *   restrictions from page table (pre 1.10)
2859          */
2860         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2861                 global $wgContLang;
2862                 $dbr = wfGetDB( DB_SLAVE );
2863
2864                 $restrictionTypes = $this->getRestrictionTypes();
2865
2866                 foreach ( $restrictionTypes as $type ) {
2867                         $this->mRestrictions[$type] = array();
2868                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2869                 }
2870
2871                 $this->mCascadeRestriction = false;
2872
2873                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2874
2875                 if ( $oldFashionedRestrictions === null ) {
2876                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2877                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2878                 }
2879
2880                 if ( $oldFashionedRestrictions != '' ) {
2881
2882                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2883                                 $temp = explode( '=', trim( $restrict ) );
2884                                 if ( count( $temp ) == 1 ) {
2885                                         // old old format should be treated as edit/move restriction
2886                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2887                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2888                                 } else {
2889                                         $restriction = trim( $temp[1] );
2890                                         if ( $restriction != '' ) { //some old entries are empty
2891                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2892                                         }
2893                                 }
2894                         }
2895
2896                         $this->mOldRestrictions = true;
2897
2898                 }
2899
2900                 if ( count( $rows ) ) {
2901                         # Current system - load second to make them override.
2902                         $now = wfTimestampNow();
2903                         $purgeExpired = false;
2904
2905                         # Cycle through all the restrictions.
2906                         foreach ( $rows as $row ) {
2907
2908                                 // Don't take care of restrictions types that aren't allowed
2909                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2910                                         continue;
2911                                 }
2912
2913                                 // This code should be refactored, now that it's being used more generally,
2914                                 // But I don't really see any harm in leaving it in Block for now -werdna
2915                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2916
2917                                 // Only apply the restrictions if they haven't expired!
2918                                 if ( !$expiry || $expiry > $now ) {
2919                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2920                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2921
2922                                         $this->mCascadeRestriction |= $row->pr_cascade;
2923                                 } else {
2924                                         // Trigger a lazy purge of expired restrictions
2925                                         $purgeExpired = true;
2926                                 }
2927                         }
2928
2929                         if ( $purgeExpired ) {
2930                                 Title::purgeExpiredRestrictions();
2931                         }
2932                 }
2933
2934                 $this->mRestrictionsLoaded = true;
2935         }
2936
2937         /**
2938          * Load restrictions from the page_restrictions table
2939          *
2940          * @param string $oldFashionedRestrictions Comma-separated list of page
2941          *   restrictions from page table (pre 1.10)
2942          */
2943         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2944                 global $wgContLang;
2945                 if ( !$this->mRestrictionsLoaded ) {
2946                         if ( $this->exists() ) {
2947                                 $dbr = wfGetDB( DB_SLAVE );
2948
2949                                 $res = $dbr->select(
2950                                         'page_restrictions',
2951                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2952                                         array( 'pr_page' => $this->getArticleID() ),
2953                                         __METHOD__
2954                                 );
2955
2956                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2957                         } else {
2958                                 $title_protection = $this->getTitleProtection();
2959
2960                                 if ( $title_protection ) {
2961                                         $now = wfTimestampNow();
2962                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2963
2964                                         if ( !$expiry || $expiry > $now ) {
2965                                                 // Apply the restrictions
2966                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2967                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2968                                         } else { // Get rid of the old restrictions
2969                                                 Title::purgeExpiredRestrictions();
2970                                                 $this->mTitleProtection = false;
2971                                         }
2972                                 } else {
2973                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2974                                 }
2975                                 $this->mRestrictionsLoaded = true;
2976                         }
2977                 }
2978         }
2979
2980         /**
2981          * Flush the protection cache in this object and force reload from the database.
2982          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2983          */
2984         public function flushRestrictions() {
2985                 $this->mRestrictionsLoaded = false;
2986                 $this->mTitleProtection = null;
2987         }
2988
2989         /**
2990          * Purge expired restrictions from the page_restrictions table
2991          */
2992         static function purgeExpiredRestrictions() {
2993                 if ( wfReadOnly() ) {
2994                         return;
2995                 }
2996
2997                 $method = __METHOD__;
2998                 $dbw = wfGetDB( DB_MASTER );
2999                 $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
3000                         $dbw->delete(
3001                                 'page_restrictions',
3002                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3003                                 $method
3004                         );
3005                         $dbw->delete(
3006                                 'protected_titles',
3007                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3008                                 $method
3009                         );
3010                 } );
3011         }
3012
3013         /**
3014          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3015          *
3016          * @return bool
3017          */
3018         public function hasSubpages() {
3019                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3020                         # Duh
3021                         return false;
3022                 }
3023
3024                 # We dynamically add a member variable for the purpose of this method
3025                 # alone to cache the result.  There's no point in having it hanging
3026                 # around uninitialized in every Title object; therefore we only add it
3027                 # if needed and don't declare it statically.
3028                 if ( $this->mHasSubpages === null ) {
3029                         $this->mHasSubpages = false;
3030                         $subpages = $this->getSubpages( 1 );
3031                         if ( $subpages instanceof TitleArray ) {
3032                                 $this->mHasSubpages = (bool)$subpages->count();
3033                         }
3034                 }
3035
3036                 return $this->mHasSubpages;
3037         }
3038
3039         /**
3040          * Get all subpages of this page.
3041          *
3042          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3043          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3044          *  doesn't allow subpages
3045          */
3046         public function getSubpages( $limit = -1 ) {
3047                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3048                         return array();
3049                 }
3050
3051                 $dbr = wfGetDB( DB_SLAVE );
3052                 $conds['page_namespace'] = $this->getNamespace();
3053                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3054                 $options = array();
3055                 if ( $limit > -1 ) {
3056                         $options['LIMIT'] = $limit;
3057                 }
3058                 $this->mSubpages = TitleArray::newFromResult(
3059                         $dbr->select( 'page',
3060                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3061                                 $conds,
3062                                 __METHOD__,
3063                                 $options
3064                         )
3065                 );
3066                 return $this->mSubpages;
3067         }
3068
3069         /**
3070          * Is there a version of this page in the deletion archive?
3071          *
3072          * @return int The number of archived revisions
3073          */
3074         public function isDeleted() {
3075                 if ( $this->getNamespace() < 0 ) {
3076                         $n = 0;
3077                 } else {
3078                         $dbr = wfGetDB( DB_SLAVE );
3079
3080                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3081                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3082                                 __METHOD__
3083                         );
3084                         if ( $this->getNamespace() == NS_FILE ) {
3085                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3086                                         array( 'fa_name' => $this->getDBkey() ),
3087                                         __METHOD__
3088                                 );
3089                         }
3090                 }
3091                 return (int)$n;
3092         }
3093
3094         /**
3095          * Is there a version of this page in the deletion archive?
3096          *
3097          * @return bool
3098          */
3099         public function isDeletedQuick() {
3100                 if ( $this->getNamespace() < 0 ) {
3101                         return false;
3102                 }
3103                 $dbr = wfGetDB( DB_SLAVE );
3104                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3105                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3106                         __METHOD__
3107                 );
3108                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3109                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3110                                 array( 'fa_name' => $this->getDBkey() ),
3111                                 __METHOD__
3112                         );
3113                 }
3114                 return $deleted;
3115         }
3116
3117         /**
3118          * Get the article ID for this Title from the link cache,
3119          * adding it if necessary
3120          *
3121          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3122          *  for update
3123          * @return int The ID
3124          */
3125         public function getArticleID( $flags = 0 ) {
3126                 if ( $this->getNamespace() < 0 ) {
3127                         $this->mArticleID = 0;
3128                         return $this->mArticleID;
3129                 }
3130                 $linkCache = LinkCache::singleton();
3131                 if ( $flags & self::GAID_FOR_UPDATE ) {
3132                         $oldUpdate = $linkCache->forUpdate( true );
3133                         $linkCache->clearLink( $this );
3134                         $this->mArticleID = $linkCache->addLinkObj( $this );
3135                         $linkCache->forUpdate( $oldUpdate );
3136                 } else {
3137                         if ( -1 == $this->mArticleID ) {
3138                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3139                         }
3140                 }
3141                 return $this->mArticleID;
3142         }
3143
3144         /**
3145          * Is this an article that is a redirect page?
3146          * Uses link cache, adding it if necessary
3147          *
3148          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3149          * @return bool
3150          */
3151         public function isRedirect( $flags = 0 ) {
3152                 if ( !is_null( $this->mRedirect ) ) {
3153                         return $this->mRedirect;
3154                 }
3155                 # Calling getArticleID() loads the field from cache as needed
3156                 if ( !$this->getArticleID( $flags ) ) {
3157                         $this->mRedirect = false;
3158                         return $this->mRedirect;
3159                 }
3160
3161                 $linkCache = LinkCache::singleton();
3162                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3163                 if ( $cached === null ) {
3164                         # Trust LinkCache's state over our own
3165                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3166                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3167                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3168                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3169                         # LinkCache to refresh its data from the master.
3170                         $this->mRedirect = false;
3171                         return $this->mRedirect;
3172                 }
3173
3174                 $this->mRedirect = (bool)$cached;
3175
3176                 return $this->mRedirect;
3177         }
3178
3179         /**
3180          * What is the length of this page?
3181          * Uses link cache, adding it if necessary
3182          *
3183          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3184          * @return int
3185          */
3186         public function getLength( $flags = 0 ) {
3187                 if ( $this->mLength != -1 ) {
3188                         return $this->mLength;
3189                 }
3190                 # Calling getArticleID() loads the field from cache as needed
3191                 if ( !$this->getArticleID( $flags ) ) {
3192                         $this->mLength = 0;
3193                         return $this->mLength;
3194                 }
3195                 $linkCache = LinkCache::singleton();
3196                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3197                 if ( $cached === null ) {
3198                         # Trust LinkCache's state over our own, as for isRedirect()
3199                         $this->mLength = 0;
3200                         return $this->mLength;
3201                 }
3202
3203                 $this->mLength = intval( $cached );
3204
3205                 return $this->mLength;
3206         }
3207
3208         /**
3209          * What is the page_latest field for this page?
3210          *
3211          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3212          * @return int Int or 0 if the page doesn't exist
3213          */
3214         public function getLatestRevID( $flags = 0 ) {
3215                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3216                         return intval( $this->mLatestID );
3217                 }
3218                 # Calling getArticleID() loads the field from cache as needed
3219                 if ( !$this->getArticleID( $flags ) ) {
3220                         $this->mLatestID = 0;
3221                         return $this->mLatestID;
3222                 }
3223                 $linkCache = LinkCache::singleton();
3224                 $linkCache->addLinkObj( $this );
3225                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3226                 if ( $cached === null ) {
3227                         # Trust LinkCache's state over our own, as for isRedirect()
3228                         $this->mLatestID = 0;
3229                         return $this->mLatestID;
3230                 }
3231
3232                 $this->mLatestID = intval( $cached );
3233
3234                 return $this->mLatestID;
3235         }
3236
3237         /**
3238          * This clears some fields in this object, and clears any associated
3239          * keys in the "bad links" section of the link cache.
3240          *
3241          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3242          * loading of the new page_id. It's also called from
3243          * WikiPage::doDeleteArticleReal()
3244          *
3245          * @param int $newid The new Article ID
3246          */
3247         public function resetArticleID( $newid ) {
3248                 $linkCache = LinkCache::singleton();
3249                 $linkCache->clearLink( $this );
3250
3251                 if ( $newid === false ) {
3252                         $this->mArticleID = -1;
3253                 } else {
3254                         $this->mArticleID = intval( $newid );
3255                 }
3256                 $this->mRestrictionsLoaded = false;
3257                 $this->mRestrictions = array();
3258                 $this->mRedirect = null;
3259                 $this->mLength = -1;
3260                 $this->mLatestID = false;
3261                 $this->mContentModel = false;
3262                 $this->mEstimateRevisions = null;
3263                 $this->mPageLanguage = false;
3264                 $this->mDbPageLanguage = null;
3265         }
3266
3267         /**
3268          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3269          *
3270          * @param string $text Containing title to capitalize
3271          * @param int $ns Namespace index, defaults to NS_MAIN
3272          * @return string Containing capitalized title
3273          */
3274         public static function capitalize( $text, $ns = NS_MAIN ) {
3275                 global $wgContLang;
3276
3277                 if ( MWNamespace::isCapitalized( $ns ) ) {
3278                         return $wgContLang->ucfirst( $text );
3279                 } else {
3280                         return $text;
3281                 }
3282         }
3283
3284         /**
3285          * Secure and split - main initialisation function for this object
3286          *
3287          * Assumes that mDbkeyform has been set, and is urldecoded
3288          * and uses underscores, but not otherwise munged.  This function
3289          * removes illegal characters, splits off the interwiki and
3290          * namespace prefixes, sets the other forms, and canonicalizes
3291          * everything.
3292          *
3293          * @return bool True on success
3294          */
3295         private function secureAndSplit() {
3296                 # Initialisation
3297                 $this->mInterwiki = '';
3298                 $this->mFragment = '';
3299                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3300
3301                 $dbkey = $this->mDbkeyform;
3302
3303                 try {
3304                         // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3305                         //        the parsing code with Title, while avoiding massive refactoring.
3306                         // @todo: get rid of secureAndSplit, refactor parsing code.
3307                         $parser = self::getTitleParser();
3308                         $parts = $parser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3309                 } catch ( MalformedTitleException $ex ) {
3310                         return false;
3311                 }
3312
3313                 # Fill fields
3314                 $this->setFragment( '#' . $parts['fragment'] );
3315                 $this->mInterwiki = $parts['interwiki'];
3316                 $this->mLocalInterwiki = $parts['local_interwiki'];
3317                 $this->mNamespace = $parts['namespace'];
3318                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3319
3320                 $this->mDbkeyform = $parts['dbkey'];
3321                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3322                 $this->mTextform = str_replace( '_', ' ', $this->mDbkeyform );
3323
3324                 # We already know that some pages won't be in the database!
3325                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3326                         $this->mArticleID = 0;
3327                 }
3328
3329                 return true;
3330         }
3331
3332         /**
3333          * Get an array of Title objects linking to this Title
3334          * Also stores the IDs in the link cache.
3335          *
3336          * WARNING: do not use this function on arbitrary user-supplied titles!
3337          * On heavily-used templates it will max out the memory.
3338          *
3339          * @param array $options May be FOR UPDATE
3340          * @param string $table Table name
3341          * @param string $prefix Fields prefix
3342          * @return Title[] Array of Title objects linking here
3343          */
3344         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3345                 if ( count( $options ) > 0 ) {
3346                         $db = wfGetDB( DB_MASTER );
3347                 } else {
3348                         $db = wfGetDB( DB_SLAVE );
3349                 }
3350
3351                 $res = $db->select(
3352                         array( 'page', $table ),
3353                         self::getSelectFields(),
3354                         array(
3355                                 "{$prefix}_from=page_id",
3356                                 "{$prefix}_namespace" => $this->getNamespace(),
3357                                 "{$prefix}_title" => $this->getDBkey() ),
3358                         __METHOD__,
3359                         $options
3360                 );
3361
3362                 $retVal = array();
3363                 if ( $res->numRows() ) {
3364                         $linkCache = LinkCache::singleton();
3365                         foreach ( $res as $row ) {
3366                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3367                                 if ( $titleObj ) {
3368                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3369                                         $retVal[] = $titleObj;
3370                                 }
3371                         }
3372                 }
3373                 return $retVal;
3374         }
3375
3376         /**
3377          * Get an array of Title objects using this Title as a template
3378          * Also stores the IDs in the link cache.
3379          *
3380          * WARNING: do not use this function on arbitrary user-supplied titles!
3381          * On heavily-used templates it will max out the memory.
3382          *
3383          * @param array $options May be FOR UPDATE
3384          * @return Title[] Array of Title the Title objects linking here
3385          */
3386         public function getTemplateLinksTo( $options = array() ) {
3387                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3388         }
3389
3390         /**
3391          * Get an array of Title objects linked from this Title
3392          * Also stores the IDs in the link cache.
3393          *
3394          * WARNING: do not use this function on arbitrary user-supplied titles!
3395          * On heavily-used templates it will max out the memory.
3396          *
3397          * @param array $options May be FOR UPDATE
3398          * @param string $table Table name
3399          * @param string $prefix Fields prefix
3400          * @return array Array of Title objects linking here
3401          */
3402         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3403                 global $wgContentHandlerUseDB;
3404
3405                 $id = $this->getArticleID();
3406
3407                 # If the page doesn't exist; there can't be any link from this page
3408                 if ( !$id ) {
3409                         return array();
3410                 }
3411
3412                 if ( count( $options ) > 0 ) {
3413                         $db = wfGetDB( DB_MASTER );
3414                 } else {
3415                         $db = wfGetDB( DB_SLAVE );
3416                 }
3417
3418                 $namespaceFiled = "{$prefix}_namespace";
3419                 $titleField = "{$prefix}_title";
3420
3421                 $fields = array(
3422                         $namespaceFiled,
3423                         $titleField,
3424                         'page_id',
3425                         'page_len',
3426                         'page_is_redirect',
3427                         'page_latest'
3428                 );
3429
3430                 if ( $wgContentHandlerUseDB ) {
3431                         $fields[] = 'page_content_model';
3432                 }
3433
3434                 $res = $db->select(
3435                         array( $table, 'page' ),
3436                         $fields,
3437                         array( "{$prefix}_from" => $id ),
3438                         __METHOD__,
3439                         $options,
3440                         array( 'page' => array(
3441                                 'LEFT JOIN',
3442                                 array( "page_namespace=$namespaceFiled", "page_title=$titleField" )
3443                         ) )
3444                 );
3445
3446                 $retVal = array();
3447                 if ( $res->numRows() ) {
3448                         $linkCache = LinkCache::singleton();
3449                         foreach ( $res as $row ) {
3450                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3451                                 if ( $titleObj ) {
3452                                         if ( $row->page_id ) {
3453                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3454                                         } else {
3455                                                 $linkCache->addBadLinkObj( $titleObj );
3456                                         }
3457                                         $retVal[] = $titleObj;
3458                                 }
3459                         }
3460                 }
3461                 return $retVal;
3462         }
3463
3464         /**
3465          * Get an array of Title objects used on this Title as a template
3466          * Also stores the IDs in the link cache.
3467          *
3468          * WARNING: do not use this function on arbitrary user-supplied titles!
3469          * On heavily-used templates it will max out the memory.
3470          *
3471          * @param array $options May be FOR UPDATE
3472          * @return Title[] Array of Title the Title objects used here
3473          */
3474         public function getTemplateLinksFrom( $options = array() ) {
3475                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3476         }
3477
3478         /**
3479          * Get an array of Title objects referring to non-existent articles linked
3480          * from this page.
3481          *
3482          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3483          *   should use redirect table in this case).
3484          * @return Title[] Array of Title the Title objects
3485          */
3486         public function getBrokenLinksFrom() {
3487                 if ( $this->getArticleID() == 0 ) {
3488                         # All links from article ID 0 are false positives
3489                         return array();
3490                 }
3491
3492                 $dbr = wfGetDB( DB_SLAVE );
3493                 $res = $dbr->select(
3494                         array( 'page', 'pagelinks' ),
3495                         array( 'pl_namespace', 'pl_title' ),
3496                         array(
3497                                 'pl_from' => $this->getArticleID(),
3498                                 'page_namespace IS NULL'
3499                         ),
3500                         __METHOD__, array(),
3501                         array(
3502                                 'page' => array(
3503                                         'LEFT JOIN',
3504                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3505                                 )
3506                         )
3507                 );
3508
3509                 $retVal = array();
3510                 foreach ( $res as $row ) {
3511                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3512                 }
3513                 return $retVal;
3514         }
3515
3516         /**
3517          * Get a list of URLs to purge from the Squid cache when this
3518          * page changes
3519          *
3520          * @return string[] Array of String the URLs
3521          */
3522         public function getSquidURLs() {
3523                 $urls = array(
3524                         $this->getInternalURL(),
3525                         $this->getInternalURL( 'action=history' )
3526                 );
3527
3528                 $pageLang = $this->getPageLanguage();
3529                 if ( $pageLang->hasVariants() ) {
3530                         $variants = $pageLang->getVariants();
3531                         foreach ( $variants as $vCode ) {
3532                                 $urls[] = $this->getInternalURL( '', $vCode );
3533                         }
3534                 }
3535
3536                 // If we are looking at a css/js user subpage, purge the action=raw.
3537                 if ( $this->isJsSubpage() ) {
3538                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3539                 } elseif ( $this->isCssSubpage() ) {
3540                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3541                 }
3542
3543                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3544                 return $urls;
3545         }
3546
3547         /**
3548          * Purge all applicable Squid URLs
3549          */
3550         public function purgeSquid() {
3551                 global $wgUseSquid;
3552                 if ( $wgUseSquid ) {
3553                         $urls = $this->getSquidURLs();
3554                         $u = new SquidUpdate( $urls );
3555                         $u->doUpdate();
3556                 }
3557         }
3558
3559         /**
3560          * Move this page without authentication
3561          *
3562          * @param Title $nt The new page Title
3563          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3564          */
3565         public function moveNoAuth( &$nt ) {
3566                 return $this->moveTo( $nt, false );
3567         }
3568
3569         /**
3570          * Check whether a given move operation would be valid.
3571          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3572          *
3573          * @param Title $nt The new title
3574          * @param bool $auth Indicates whether $wgUser's permissions
3575          *  should be checked
3576          * @param string $reason Is the log summary of the move, used for spam checking
3577          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3578          */
3579         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3580                 global $wgUser, $wgContentHandlerUseDB;
3581
3582                 $errors = array();
3583                 if ( !$nt ) {
3584                         // Normally we'd add this to $errors, but we'll get
3585                         // lots of syntax errors if $nt is not an object
3586                         return array( array( 'badtitletext' ) );
3587                 }
3588                 if ( $this->equals( $nt ) ) {
3589                         $errors[] = array( 'selfmove' );
3590                 }
3591                 if ( !$this->isMovable() ) {
3592                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3593                 }
3594                 if ( $nt->isExternal() ) {
3595                         $errors[] = array( 'immobile-target-namespace-iw' );
3596                 }
3597                 if ( !$nt->isMovable() ) {
3598                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3599                 }
3600
3601                 $oldid = $this->getArticleID();
3602                 $newid = $nt->getArticleID();
3603
3604                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3605                         $errors[] = array( 'articleexists' );
3606                 }
3607                 if (
3608                         ( $this->getDBkey() == '' ) ||
3609                         ( !$oldid ) ||
3610                         ( $nt->getDBkey() == '' )
3611                 ) {
3612                         $errors[] = array( 'badarticleerror' );
3613                 }
3614
3615                 // Content model checks
3616                 if ( !$wgContentHandlerUseDB &&
3617                                 $this->getContentModel() !== $nt->getContentModel() ) {
3618                         // can't move a page if that would change the page's content model
3619                         $errors[] = array(
3620                                 'bad-target-model',
3621                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3622                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3623                         );
3624                 }
3625
3626                 // Image-specific checks
3627                 if ( $this->getNamespace() == NS_FILE ) {
3628                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3629                 }
3630
3631                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3632                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3633                 }
3634
3635                 if ( $auth ) {
3636                         $errors = wfMergeErrorArrays( $errors,
3637                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3638                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3639                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3640                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3641                 }
3642
3643                 $match = EditPage::matchSummarySpamRegex( $reason );
3644                 if ( $match !== false ) {
3645                         // This is kind of lame, won't display nice
3646                         $errors[] = array( 'spamprotectiontext' );
3647                 }
3648
3649                 $err = null;
3650                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3651                         $errors[] = array( 'hookaborted', $err );
3652                 }
3653
3654                 # The move is allowed only if (1) the target doesn't exist, or
3655                 # (2) the target is a redirect to the source, and has no history
3656                 # (so we can undo bad moves right after they're done).
3657
3658                 if ( 0 != $newid ) { # Target exists; check for validity
3659                         if ( !$this->isValidMoveTarget( $nt ) ) {
3660                                 $errors[] = array( 'articleexists' );
3661                         }
3662                 } else {
3663                         $tp = $nt->getTitleProtection();
3664                         $right = $tp['pt_create_perm'];
3665                         if ( $right == 'sysop' ) {
3666                                 $right = 'editprotected'; // B/C
3667                         }
3668                         if ( $right == 'autoconfirmed' ) {
3669                                 $right = 'editsemiprotected'; // B/C
3670                         }
3671                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3672                                 $errors[] = array( 'cantmove-titleprotected' );
3673                         }
3674                 }
3675                 if ( empty( $errors ) ) {
3676                         return true;
3677                 }
3678                 return $errors;
3679         }
3680
3681         /**
3682          * Check if the requested move target is a valid file move target
3683          * @param Title $nt Target title
3684          * @return array List of errors
3685          */
3686         protected function validateFileMoveOperation( $nt ) {
3687                 global $wgUser;
3688
3689                 $errors = array();
3690
3691                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3692
3693                 $file = wfLocalFile( $this );
3694                 if ( $file->exists() ) {
3695                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3696                                 $errors[] = array( 'imageinvalidfilename' );
3697                         }
3698                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3699                                 $errors[] = array( 'imagetypemismatch' );
3700                         }
3701                 }
3702
3703                 if ( $nt->getNamespace() != NS_FILE ) {
3704                         $errors[] = array( 'imagenocrossnamespace' );
3705                         // From here we want to do checks on a file object, so if we can't
3706                         // create one, we must return.
3707                         return $errors;
3708                 }
3709
3710                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3711
3712                 $destFile = wfLocalFile( $nt );
3713                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3714                         $errors[] = array( 'file-exists-sharedrepo' );
3715                 }
3716
3717                 return $errors;
3718         }
3719
3720         /**
3721          * Move a title to a new location
3722          *
3723          * @param Title $nt The new title
3724          * @param bool $auth Indicates whether $wgUser's permissions
3725          *  should be checked
3726          * @param string $reason The reason for the move
3727          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3728          *  Ignored if the user doesn't have the suppressredirect right.
3729          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3730          */
3731         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3732                 global $wgUser;
3733                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3734                 if ( is_array( $err ) ) {
3735                         // Auto-block user's IP if the account was "hard" blocked
3736                         $wgUser->spreadAnyEditBlock();
3737                         return $err;
3738                 }
3739                 // Check suppressredirect permission
3740                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3741                         $createRedirect = true;
3742                 }
3743
3744                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3745
3746                 // If it is a file, move it first.
3747                 // It is done before all other moving stuff is done because it's hard to revert.
3748                 $dbw = wfGetDB( DB_MASTER );
3749                 if ( $this->getNamespace() == NS_FILE ) {
3750                         $file = wfLocalFile( $this );
3751                         if ( $file->exists() ) {
3752                                 $status = $file->move( $nt );
3753                                 if ( !$status->isOk() ) {
3754                                         return $status->getErrorsArray();
3755                                 }
3756                         }
3757                         // Clear RepoGroup process cache
3758                         RepoGroup::singleton()->clearCache( $this );
3759                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3760                 }
3761
3762                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3763                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3764                 $protected = $this->isProtected();
3765
3766                 // Do the actual move
3767                 $this->moveToInternal( $nt, $reason, $createRedirect );
3768
3769                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3770                 // cl_timestamp, which may disturb time-based lists on some sites.
3771                 $prefixes = $dbw->select(
3772                         'categorylinks',
3773                         array( 'cl_sortkey_prefix', 'cl_to' ),
3774                         array( 'cl_from' => $pageid ),
3775                         __METHOD__
3776                 );
3777                 foreach ( $prefixes as $prefixRow ) {
3778                         $prefix = $prefixRow->cl_sortkey_prefix;
3779                         $catTo = $prefixRow->cl_to;
3780                         $dbw->update( 'categorylinks',
3781                                 array(
3782                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3783                                                 $nt->getCategorySortkey( $prefix ) ),
3784                                         'cl_timestamp=cl_timestamp' ),
3785                                 array(
3786                                         'cl_from' => $pageid,
3787                                         'cl_to' => $catTo ),
3788                                 __METHOD__
3789                         );
3790                 }
3791
3792                 $redirid = $this->getArticleID();
3793
3794                 if ( $protected ) {
3795                         # Protect the redirect title as the title used to be...
3796                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3797                                 array(
3798                                         'pr_page' => $redirid,
3799                                         'pr_type' => 'pr_type',
3800                                         'pr_level' => 'pr_level',
3801                                         'pr_cascade' => 'pr_cascade',
3802                                         'pr_user' => 'pr_user',
3803                                         'pr_expiry' => 'pr_expiry'
3804                                 ),
3805                                 array( 'pr_page' => $pageid ),
3806                                 __METHOD__,
3807                                 array( 'IGNORE' )
3808                         );
3809                         # Update the protection log
3810                         $log = new LogPage( 'protect' );
3811                         $comment = wfMessage(
3812                                 'prot_1movedto2',
3813                                 $this->getPrefixedText(),
3814                                 $nt->getPrefixedText()
3815                         )->inContentLanguage()->text();
3816                         if ( $reason ) {
3817                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3818                         }
3819                         // @todo FIXME: $params?
3820                         $logId = $log->addEntry(
3821                                 'move_prot',
3822                                 $nt,
3823                                 $comment,
3824                                 array( $this->getPrefixedText() ),
3825                                 $wgUser
3826                         );
3827
3828                         // reread inserted pr_ids for log relation
3829                         $insertedPrIds = $dbw->select(
3830                                 'page_restrictions',
3831                                 'pr_id',
3832                                 array( 'pr_page' => $redirid ),
3833                                 __METHOD__
3834                         );
3835                         $logRelationsValues = array();
3836                         foreach ( $insertedPrIds as $prid ) {
3837                                 $logRelationsValues[] = $prid->pr_id;
3838                         }
3839                         $log->addRelations( 'pr_id', $logRelationsValues, $logId );
3840                 }
3841
3842                 // Update *_from_namespace fields as needed
3843                 if ( $this->getNamespace() != $nt->getNamespace() ) {
3844                         $dbw->update( 'pagelinks',
3845                                 array( 'pl_from_namespace' => $nt->getNamespace() ),
3846                                 array( 'pl_from' => $pageid ),
3847                                 __METHOD__
3848                         );
3849                         $dbw->update( 'templatelinks',
3850                                 array( 'tl_from_namespace' => $nt->getNamespace() ),
3851                                 array( 'tl_from' => $pageid ),
3852                                 __METHOD__
3853                         );
3854                         $dbw->update( 'imagelinks',
3855                                 array( 'il_from_namespace' => $nt->getNamespace() ),
3856                                 array( 'il_from' => $pageid ),
3857                                 __METHOD__
3858                         );
3859                 }
3860
3861                 # Update watchlists
3862                 $oldtitle = $this->getDBkey();
3863                 $newtitle = $nt->getDBkey();
3864                 $oldsnamespace = MWNamespace::getSubject( $this->getNamespace() );
3865                 $newsnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3866                 if ( $oldsnamespace != $newsnamespace || $oldtitle != $newtitle ) {
3867                         WatchedItem::duplicateEntries( $this, $nt );
3868                 }
3869
3870                 $dbw->commit( __METHOD__ );
3871
3872                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid, $reason ) );
3873                 return true;
3874         }
3875
3876         /**
3877          * Move page to a title which is either a redirect to the
3878          * source page or nonexistent
3879          *
3880          * @param Title $nt The page to move to, which should be a redirect or nonexistent
3881          * @param string $reason The reason for the move
3882          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3883          *   if the user has the suppressredirect right
3884          * @throws MWException
3885          */
3886         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3887                 global $wgUser, $wgContLang;
3888
3889                 if ( $nt->exists() ) {
3890                         $moveOverRedirect = true;
3891                         $logType = 'move_redir';
3892                 } else {
3893                         $moveOverRedirect = false;
3894                         $logType = 'move';
3895                 }
3896
3897                 if ( $createRedirect ) {
3898                         if ( $this->getNamespace() == NS_CATEGORY
3899                                 && !wfMessage( 'category-move-redirect-override' )->inContentLanguage()->isDisabled()
3900                         ) {
3901                                 $redirectContent = new WikitextContent(
3902                                         wfMessage( 'category-move-redirect-override' )
3903                                                 ->params( $nt->getPrefixedText() )->inContentLanguage()->plain() );
3904                         } else {
3905                                 $contentHandler = ContentHandler::getForTitle( $this );
3906                                 $redirectContent = $contentHandler->makeRedirectContent( $nt,
3907                                         wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3908                         }
3909
3910                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3911                 } else {
3912                         $redirectContent = null;
3913                 }
3914
3915                 $logEntry = new ManualLogEntry( 'move', $logType );
3916                 $logEntry->setPerformer( $wgUser );
3917                 $logEntry->setTarget( $this );
3918                 $logEntry->setComment( $reason );
3919                 $logEntry->setParameters( array(
3920                         '4::target' => $nt->getPrefixedText(),
3921                         '5::noredir' => $redirectContent ? '0': '1',
3922                 ) );
3923
3924                 $formatter = LogFormatter::newFromEntry( $logEntry );
3925                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3926                 $comment = $formatter->getPlainActionText();
3927                 if ( $reason ) {
3928                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3929                 }
3930                 # Truncate for whole multibyte characters.
3931                 $comment = $wgContLang->truncate( $comment, 255 );
3932
3933                 $oldid = $this->getArticleID();
3934
3935                 $dbw = wfGetDB( DB_MASTER );
3936
3937                 $newpage = WikiPage::factory( $nt );
3938
3939                 if ( $moveOverRedirect ) {
3940                         $newid = $nt->getArticleID();
3941                         $newcontent = $newpage->getContent();
3942
3943                         # Delete the old redirect. We don't save it to history since
3944                         # by definition if we've got here it's rather uninteresting.
3945                         # We have to remove it so that the next step doesn't trigger
3946                         # a conflict on the unique namespace+title index...
3947                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3948
3949                         $newpage->doDeleteUpdates( $newid, $newcontent );
3950                 }
3951
3952                 # Save a null revision in the page's history notifying of the move
3953                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true, $wgUser );
3954                 if ( !is_object( $nullRevision ) ) {
3955                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3956                 }
3957
3958                 $nullRevision->insertOn( $dbw );
3959
3960                 # Change the name of the target page:
3961                 $dbw->update( 'page',
3962                         /* SET */ array(
3963                                 'page_namespace' => $nt->getNamespace(),
3964                                 'page_title' => $nt->getDBkey(),
3965                         ),
3966                         /* WHERE */ array( 'page_id' => $oldid ),
3967                         __METHOD__
3968                 );
3969
3970                 // clean up the old title before reset article id - bug 45348
3971                 if ( !$redirectContent ) {
3972                         WikiPage::onArticleDelete( $this );
3973                 }
3974
3975                 $this->resetArticleID( 0 ); // 0 == non existing
3976                 $nt->resetArticleID( $oldid );
3977                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
3978
3979                 $newpage->updateRevisionOn( $dbw, $nullRevision );
3980
3981                 wfRunHooks( 'NewRevisionFromEditComplete',
3982                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
3983
3984                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
3985
3986                 if ( !$moveOverRedirect ) {
3987                         WikiPage::onArticleCreate( $nt );
3988                 }
3989
3990                 # Recreate the redirect, this time in the other direction.
3991                 if ( $redirectContent ) {
3992                         $redirectArticle = WikiPage::factory( $this );
3993                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
3994                         $newid = $redirectArticle->insertOn( $dbw );
3995                         if ( $newid ) { // sanity
3996                                 $this->resetArticleID( $newid );
3997                                 $redirectRevision = new Revision( array(
3998                                         'title' => $this, // for determining the default content model
3999                                         'page' => $newid,
4000                                         'user_text' => $wgUser->getName(),
4001                                         'user' => $wgUser->getId(),
4002                                         'comment' => $comment,
4003                                         'content' => $redirectContent ) );
4004                                 $redirectRevision->insertOn( $dbw );
4005                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
4006
4007                                 wfRunHooks( 'NewRevisionFromEditComplete',
4008                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
4009
4010                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
4011                         }
4012                 }
4013
4014                 # Log the move
4015                 $logid = $logEntry->insert();
4016                 $logEntry->publish( $logid );
4017         }
4018
4019         /**
4020          * Move this page's subpages to be subpages of $nt
4021          *
4022          * @param Title $nt Move target
4023          * @param bool $auth Whether $wgUser's permissions should be checked
4024          * @param string $reason The reason for the move
4025          * @param bool $createRedirect Whether to create redirects from the old subpages to
4026          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4027          * @return array Array with old page titles as keys, and strings (new page titles) or
4028          *     arrays (errors) as values, or an error array with numeric indices if no pages
4029          *     were moved
4030          */
4031         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
4032                 global $wgMaximumMovedPages;
4033                 // Check permissions
4034                 if ( !$this->userCan( 'move-subpages' ) ) {
4035                         return array( 'cant-move-subpages' );
4036                 }
4037                 // Do the source and target namespaces support subpages?
4038                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4039                         return array( 'namespace-nosubpages',
4040                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
4041                 }
4042                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4043                         return array( 'namespace-nosubpages',
4044                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
4045                 }
4046
4047                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4048                 $retval = array();
4049                 $count = 0;
4050                 foreach ( $subpages as $oldSubpage ) {
4051                         $count++;
4052                         if ( $count > $wgMaximumMovedPages ) {
4053                                 $retval[$oldSubpage->getPrefixedText()] =
4054                                                 array( 'movepage-max-pages',
4055                                                         $wgMaximumMovedPages );
4056                                 break;
4057                         }
4058
4059                         // We don't know whether this function was called before
4060                         // or after moving the root page, so check both
4061                         // $this and $nt
4062                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4063                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4064                         ) {
4065                                 // When moving a page to a subpage of itself,
4066                                 // don't move it twice
4067                                 continue;
4068                         }
4069                         $newPageName = preg_replace(
4070                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4071                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4072                                         $oldSubpage->getDBkey() );
4073                         if ( $oldSubpage->isTalkPage() ) {
4074                                 $newNs = $nt->getTalkPage()->getNamespace();
4075                         } else {
4076                                 $newNs = $nt->getSubjectPage()->getNamespace();
4077                         }
4078                         # Bug 14385: we need makeTitleSafe because the new page names may
4079                         # be longer than 255 characters.
4080                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4081
4082                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4083                         if ( $success === true ) {
4084                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4085                         } else {
4086                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4087                         }
4088                 }
4089                 return $retval;
4090         }
4091
4092         /**
4093          * Checks if this page is just a one-rev redirect.
4094          * Adds lock, so don't use just for light purposes.
4095          *
4096          * @return bool
4097          */
4098         public function isSingleRevRedirect() {
4099                 global $wgContentHandlerUseDB;
4100
4101                 $dbw = wfGetDB( DB_MASTER );
4102
4103                 # Is it a redirect?
4104                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4105                 if ( $wgContentHandlerUseDB ) {
4106                         $fields[] = 'page_content_model';
4107                 }
4108
4109                 $row = $dbw->selectRow( 'page',
4110                         $fields,
4111                         $this->pageCond(),
4112                         __METHOD__,
4113                         array( 'FOR UPDATE' )
4114                 );
4115                 # Cache some fields we may want
4116                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4117                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4118                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4119                 $this->mContentModel = $row && isset( $row->page_content_model )
4120                         ? strval( $row->page_content_model )
4121                         : false;
4122
4123                 if ( !$this->mRedirect ) {
4124                         return false;
4125                 }
4126                 # Does the article have a history?
4127                 $row = $dbw->selectField( array( 'page', 'revision' ),
4128                         'rev_id',
4129                         array( 'page_namespace' => $this->getNamespace(),
4130                                 'page_title' => $this->getDBkey(),
4131                                 'page_id=rev_page',
4132                                 'page_latest != rev_id'
4133                         ),
4134                         __METHOD__,
4135                         array( 'FOR UPDATE' )
4136                 );
4137                 # Return true if there was no history
4138                 return ( $row === false );
4139         }
4140
4141         /**
4142          * Checks if $this can be moved to a given Title
4143          * - Selects for update, so don't call it unless you mean business
4144          *
4145          * @param Title $nt The new title to check
4146          * @return bool
4147          */
4148         public function isValidMoveTarget( $nt ) {
4149                 # Is it an existing file?
4150                 if ( $nt->getNamespace() == NS_FILE ) {
4151                         $file = wfLocalFile( $nt );
4152                         if ( $file->exists() ) {
4153                                 wfDebug( __METHOD__ . ": file exists\n" );
4154                                 return false;
4155                         }
4156                 }
4157                 # Is it a redirect with no history?
4158                 if ( !$nt->isSingleRevRedirect() ) {
4159                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4160                         return false;
4161                 }
4162                 # Get the article text
4163                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4164                 if ( !is_object( $rev ) ) {
4165                         return false;
4166                 }
4167                 $content = $rev->getContent();
4168                 # Does the redirect point to the source?
4169                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4170                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4171
4172                 if ( $redirTitle ) {
4173                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4174                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4175                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4176                                 return false;
4177                         } else {
4178                                 return true;
4179                         }
4180                 } else {
4181                         # Fail safe (not a redirect after all. strange.)
4182                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4183                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4184                         return false;
4185                 }
4186         }
4187
4188         /**
4189          * Get categories to which this Title belongs and return an array of
4190          * categories' names.
4191          *
4192          * @return array Array of parents in the form:
4193          *        $parent => $currentarticle
4194          */
4195         public function getParentCategories() {
4196                 global $wgContLang;
4197
4198                 $data = array();
4199
4200                 $titleKey = $this->getArticleID();
4201
4202                 if ( $titleKey === 0 ) {
4203                         return $data;
4204                 }
4205
4206                 $dbr = wfGetDB( DB_SLAVE );
4207
4208                 $res = $dbr->select(
4209                         'categorylinks',
4210                         'cl_to',
4211                         array( 'cl_from' => $titleKey ),
4212                         __METHOD__
4213                 );
4214
4215                 if ( $res->numRows() > 0 ) {
4216                         foreach ( $res as $row ) {
4217                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4218                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4219                         }
4220                 }
4221                 return $data;
4222         }
4223
4224         /**
4225          * Get a tree of parent categories
4226          *
4227          * @param array $children Array with the children in the keys, to check for circular refs
4228          * @return array Tree of parent categories
4229          */
4230         public function getParentCategoryTree( $children = array() ) {
4231                 $stack = array();
4232                 $parents = $this->getParentCategories();
4233
4234                 if ( $parents ) {
4235                         foreach ( $parents as $parent => $current ) {
4236                                 if ( array_key_exists( $parent, $children ) ) {
4237                                         # Circular reference
4238                                         $stack[$parent] = array();
4239                                 } else {
4240                                         $nt = Title::newFromText( $parent );
4241                                         if ( $nt ) {
4242                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4243                                         }
4244                                 }
4245                         }
4246                 }
4247
4248                 return $stack;
4249         }
4250
4251         /**
4252          * Get an associative array for selecting this title from
4253          * the "page" table
4254          *
4255          * @return array Array suitable for the $where parameter of DB::select()
4256          */
4257         public function pageCond() {
4258                 if ( $this->mArticleID > 0 ) {
4259                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4260                         return array( 'page_id' => $this->mArticleID );
4261                 } else {
4262                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4263                 }
4264         }
4265
4266         /**
4267          * Get the revision ID of the previous revision
4268          *
4269          * @param int $revId Revision ID. Get the revision that was before this one.
4270          * @param int $flags Title::GAID_FOR_UPDATE
4271          * @return int|bool Old revision ID, or false if none exists
4272          */
4273         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4274                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4275                 $revId = $db->selectField( 'revision', 'rev_id',
4276                         array(
4277                                 'rev_page' => $this->getArticleID( $flags ),
4278                                 'rev_id < ' . intval( $revId )
4279                         ),
4280                         __METHOD__,
4281                         array( 'ORDER BY' => 'rev_id DESC' )
4282                 );
4283
4284                 if ( $revId === false ) {
4285                         return false;
4286                 } else {
4287                         return intval( $revId );
4288                 }
4289         }
4290
4291         /**
4292          * Get the revision ID of the next revision
4293          *
4294          * @param int $revId Revision ID. Get the revision that was after this one.
4295          * @param int $flags Title::GAID_FOR_UPDATE
4296          * @return int|bool Next revision ID, or false if none exists
4297          */
4298         public function getNextRevisionID( $revId, $flags = 0 ) {
4299                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4300                 $revId = $db->selectField( 'revision', 'rev_id',
4301                         array(
4302                                 'rev_page' => $this->getArticleID( $flags ),
4303                                 'rev_id > ' . intval( $revId )
4304                         ),
4305                         __METHOD__,
4306                         array( 'ORDER BY' => 'rev_id' )
4307                 );
4308
4309                 if ( $revId === false ) {
4310                         return false;
4311                 } else {
4312                         return intval( $revId );
4313                 }
4314         }
4315
4316         /**
4317          * Get the first revision of the page
4318          *
4319          * @param int $flags Title::GAID_FOR_UPDATE
4320          * @return Revision|null If page doesn't exist
4321          */
4322         public function getFirstRevision( $flags = 0 ) {
4323                 $pageId = $this->getArticleID( $flags );
4324                 if ( $pageId ) {
4325                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4326                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4327                                 array( 'rev_page' => $pageId ),
4328                                 __METHOD__,
4329                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4330                         );
4331                         if ( $row ) {
4332                                 return new Revision( $row );
4333                         }
4334                 }
4335                 return null;
4336         }
4337
4338         /**
4339          * Get the oldest revision timestamp of this page
4340          *
4341          * @param int $flags Title::GAID_FOR_UPDATE
4342          * @return string MW timestamp
4343          */
4344         public function getEarliestRevTime( $flags = 0 ) {
4345                 $rev = $this->getFirstRevision( $flags );
4346                 return $rev ? $rev->getTimestamp() : null;
4347         }
4348
4349         /**
4350          * Check if this is a new page
4351          *
4352          * @return bool
4353          */
4354         public function isNewPage() {
4355                 $dbr = wfGetDB( DB_SLAVE );
4356                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4357         }
4358
4359         /**
4360          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4361          *
4362          * @return bool
4363          */
4364         public function isBigDeletion() {
4365                 global $wgDeleteRevisionsLimit;
4366
4367                 if ( !$wgDeleteRevisionsLimit ) {
4368                         return false;
4369                 }
4370
4371                 $revCount = $this->estimateRevisionCount();
4372                 return $revCount > $wgDeleteRevisionsLimit;
4373         }
4374
4375         /**
4376          * Get the  approximate revision count of this page.
4377          *
4378          * @return int
4379          */
4380         public function estimateRevisionCount() {
4381                 if ( !$this->exists() ) {
4382                         return 0;
4383                 }
4384
4385                 if ( $this->mEstimateRevisions === null ) {
4386                         $dbr = wfGetDB( DB_SLAVE );
4387                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4388                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4389                 }
4390
4391                 return $this->mEstimateRevisions;
4392         }
4393
4394         /**
4395          * Get the number of revisions between the given revision.
4396          * Used for diffs and other things that really need it.
4397          *
4398          * @param int|Revision $old Old revision or rev ID (first before range)
4399          * @param int|Revision $new New revision or rev ID (first after range)
4400          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4401          * @return int Number of revisions between these revisions.
4402          */
4403         public function countRevisionsBetween( $old, $new, $max = null ) {
4404                 if ( !( $old instanceof Revision ) ) {
4405                         $old = Revision::newFromTitle( $this, (int)$old );
4406                 }
4407                 if ( !( $new instanceof Revision ) ) {
4408                         $new = Revision::newFromTitle( $this, (int)$new );
4409                 }
4410                 if ( !$old || !$new ) {
4411                         return 0; // nothing to compare
4412                 }
4413                 $dbr = wfGetDB( DB_SLAVE );
4414                 $conds = array(
4415                         'rev_page' => $this->getArticleID(),
4416                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4417                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4418                 );
4419                 if ( $max !== null ) {
4420                         $res = $dbr->select( 'revision', '1',
4421                                 $conds,
4422                                 __METHOD__,
4423                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4424                         );
4425                         return $res->numRows();
4426                 } else {
4427                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4428                 }
4429         }
4430
4431         /**
4432          * Get the authors between the given revisions or revision IDs.
4433          * Used for diffs and other things that really need it.
4434          *
4435          * @since 1.23
4436          *
4437          * @param int|Revision $old Old revision or rev ID (first before range by default)
4438          * @param int|Revision $new New revision or rev ID (first after range by default)
4439          * @param int $limit Maximum number of authors
4440          * @param string|array $options (Optional): Single option, or an array of options:
4441          *     'include_old' Include $old in the range; $new is excluded.
4442          *     'include_new' Include $new in the range; $old is excluded.
4443          *     'include_both' Include both $old and $new in the range.
4444          *     Unknown option values are ignored.
4445          * @return array|null Names of revision authors in the range; null if not both revisions exist
4446          */
4447         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4448                 if ( !( $old instanceof Revision ) ) {
4449                         $old = Revision::newFromTitle( $this, (int)$old );
4450                 }
4451                 if ( !( $new instanceof Revision ) ) {
4452                         $new = Revision::newFromTitle( $this, (int)$new );
4453                 }
4454                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4455                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4456                 // in the sanity check below?
4457                 if ( !$old || !$new ) {
4458                         return null; // nothing to compare
4459                 }
4460                 $authors = array();
4461                 $old_cmp = '>';
4462                 $new_cmp = '<';
4463                 $options = (array)$options;
4464                 if ( in_array( 'include_old', $options ) ) {
4465                         $old_cmp = '>=';
4466                 }
4467                 if ( in_array( 'include_new', $options ) ) {
4468                         $new_cmp = '<=';
4469                 }
4470                 if ( in_array( 'include_both', $options ) ) {
4471                         $old_cmp = '>=';
4472                         $new_cmp = '<=';
4473                 }
4474                 // No DB query needed if $old and $new are the same or successive revisions:
4475                 if ( $old->getId() === $new->getId() ) {
4476                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? array() : array( $old->getRawUserText() );
4477                 } elseif ( $old->getId() === $new->getParentId() ) {
4478                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4479                                 $authors[] = $old->getRawUserText();
4480                                 if ( $old->getRawUserText() != $new->getRawUserText() ) {
4481                                         $authors[] = $new->getRawUserText();
4482                                 }
4483                         } elseif ( $old_cmp === '>=' ) {
4484                                 $authors[] = $old->getRawUserText();
4485                         } elseif ( $new_cmp === '<=' ) {
4486                                 $authors[] = $new->getRawUserText();
4487                         }
4488                         return $authors;
4489                 }
4490                 $dbr = wfGetDB( DB_SLAVE );
4491                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4492                         array(
4493                                 'rev_page' => $this->getArticleID(),
4494                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4495                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4496                         ), __METHOD__,
4497                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4498                 );
4499                 foreach ( $res as $row ) {
4500                         $authors[] = $row->rev_user_text;
4501                 }
4502                 return $authors;
4503         }
4504
4505         /**
4506          * Get the number of authors between the given revisions or revision IDs.
4507          * Used for diffs and other things that really need it.
4508          *
4509          * @param int|Revision $old Old revision or rev ID (first before range by default)
4510          * @param int|Revision $new New revision or rev ID (first after range by default)
4511          * @param int $limit Maximum number of authors
4512          * @param string|array $options (Optional): Single option, or an array of options:
4513          *     'include_old' Include $old in the range; $new is excluded.
4514          *     'include_new' Include $new in the range; $old is excluded.
4515          *     'include_both' Include both $old and $new in the range.
4516          *     Unknown option values are ignored.
4517          * @return int Number of revision authors in the range; zero if not both revisions exist
4518          */
4519         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4520                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4521                 return $authors ? count( $authors ) : 0;
4522         }
4523
4524         /**
4525          * Compare with another title.
4526          *
4527          * @param Title $title
4528          * @return bool
4529          */
4530         public function equals( Title $title ) {
4531                 // Note: === is necessary for proper matching of number-like titles.
4532                 return $this->getInterwiki() === $title->getInterwiki()
4533                         && $this->getNamespace() == $title->getNamespace()
4534                         && $this->getDBkey() === $title->getDBkey();
4535         }
4536
4537         /**
4538          * Check if this title is a subpage of another title
4539          *
4540          * @param Title $title
4541          * @return bool
4542          */
4543         public function isSubpageOf( Title $title ) {
4544                 return $this->getInterwiki() === $title->getInterwiki()
4545                         && $this->getNamespace() == $title->getNamespace()
4546                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4547         }
4548
4549         /**
4550          * Check if page exists.  For historical reasons, this function simply
4551          * checks for the existence of the title in the page table, and will
4552          * thus return false for interwiki links, special pages and the like.
4553          * If you want to know if a title can be meaningfully viewed, you should
4554          * probably call the isKnown() method instead.
4555          *
4556          * @return bool
4557          */
4558         public function exists() {
4559                 return $this->getArticleID() != 0;
4560         }
4561
4562         /**
4563          * Should links to this title be shown as potentially viewable (i.e. as
4564          * "bluelinks"), even if there's no record by this title in the page
4565          * table?
4566          *
4567          * This function is semi-deprecated for public use, as well as somewhat
4568          * misleadingly named.  You probably just want to call isKnown(), which
4569          * calls this function internally.
4570          *
4571          * (ISSUE: Most of these checks are cheap, but the file existence check
4572          * can potentially be quite expensive.  Including it here fixes a lot of
4573          * existing code, but we might want to add an optional parameter to skip
4574          * it and any other expensive checks.)
4575          *
4576          * @return bool
4577          */
4578         public function isAlwaysKnown() {
4579                 $isKnown = null;
4580
4581                 /**
4582                  * Allows overriding default behavior for determining if a page exists.
4583                  * If $isKnown is kept as null, regular checks happen. If it's
4584                  * a boolean, this value is returned by the isKnown method.
4585                  *
4586                  * @since 1.20
4587                  *
4588                  * @param Title $title
4589                  * @param bool|null $isKnown
4590                  */
4591                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4592
4593                 if ( !is_null( $isKnown ) ) {
4594                         return $isKnown;
4595                 }
4596
4597                 if ( $this->isExternal() ) {
4598                         return true;  // any interwiki link might be viewable, for all we know
4599                 }
4600
4601                 switch ( $this->mNamespace ) {
4602                         case NS_MEDIA:
4603                         case NS_FILE:
4604                                 // file exists, possibly in a foreign repo
4605                                 return (bool)wfFindFile( $this );
4606                         case NS_SPECIAL:
4607                                 // valid special page
4608                                 return SpecialPageFactory::exists( $this->getDBkey() );
4609                         case NS_MAIN:
4610                                 // selflink, possibly with fragment
4611                                 return $this->mDbkeyform == '';
4612                         case NS_MEDIAWIKI:
4613                                 // known system message
4614                                 return $this->hasSourceText() !== false;
4615                         default:
4616                                 return false;
4617                 }
4618         }
4619
4620         /**
4621          * Does this title refer to a page that can (or might) be meaningfully
4622          * viewed?  In particular, this function may be used to determine if
4623          * links to the title should be rendered as "bluelinks" (as opposed to
4624          * "redlinks" to non-existent pages).
4625          * Adding something else to this function will cause inconsistency
4626          * since LinkHolderArray calls isAlwaysKnown() and does its own
4627          * page existence check.
4628          *
4629          * @return bool
4630          */
4631         public function isKnown() {
4632                 return $this->isAlwaysKnown() || $this->exists();
4633         }
4634
4635         /**
4636          * Does this page have source text?
4637          *
4638          * @return bool
4639          */
4640         public function hasSourceText() {
4641                 if ( $this->exists() ) {
4642                         return true;
4643                 }
4644
4645                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4646                         // If the page doesn't exist but is a known system message, default
4647                         // message content will be displayed, same for language subpages-
4648                         // Use always content language to avoid loading hundreds of languages
4649                         // to get the link color.
4650                         global $wgContLang;
4651                         list( $name, ) = MessageCache::singleton()->figureMessage(
4652                                 $wgContLang->lcfirst( $this->getText() )
4653                         );
4654                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4655                         return $message->exists();
4656                 }
4657
4658                 return false;
4659         }
4660
4661         /**
4662          * Get the default message text or false if the message doesn't exist
4663          *
4664          * @return string|bool
4665          */
4666         public function getDefaultMessageText() {
4667                 global $wgContLang;
4668
4669                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4670                         return false;
4671                 }
4672
4673                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4674                         $wgContLang->lcfirst( $this->getText() )
4675                 );
4676                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4677
4678                 if ( $message->exists() ) {
4679                         return $message->plain();
4680                 } else {
4681                         return false;
4682                 }
4683         }
4684
4685         /**
4686          * Updates page_touched for this page; called from LinksUpdate.php
4687          *
4688          * @return bool True if the update succeeded
4689          */
4690         public function invalidateCache() {
4691                 if ( wfReadOnly() ) {
4692                         return false;
4693                 }
4694
4695                 if ( $this->mArticleID === 0 ) {
4696                         return true; // avoid gap locking if we know it's not there
4697                 }
4698
4699                 $method = __METHOD__;
4700                 $dbw = wfGetDB( DB_MASTER );
4701                 $conds = $this->pageCond();
4702                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method ) {
4703                         $dbw->update(
4704                                 'page',
4705                                 array( 'page_touched' => $dbw->timestamp() ),
4706                                 $conds,
4707                                 $method
4708                         );
4709                 } );
4710
4711                 return true;
4712         }
4713
4714         /**
4715          * Update page_touched timestamps and send squid purge messages for
4716          * pages linking to this title. May be sent to the job queue depending
4717          * on the number of links. Typically called on create and delete.
4718          */
4719         public function touchLinks() {
4720                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4721                 $u->doUpdate();
4722
4723                 if ( $this->getNamespace() == NS_CATEGORY ) {
4724                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4725                         $u->doUpdate();
4726                 }
4727         }
4728
4729         /**
4730          * Get the last touched timestamp
4731          *
4732          * @param DatabaseBase $db Optional db
4733          * @return string Last-touched timestamp
4734          */
4735         public function getTouched( $db = null ) {
4736                 if ( $db === null ) {
4737                         $db = wfGetDB( DB_SLAVE );
4738                 }
4739                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4740                 return $touched;
4741         }
4742
4743         /**
4744          * Get the timestamp when this page was updated since the user last saw it.
4745          *
4746          * @param User $user
4747          * @return string|null
4748          */
4749         public function getNotificationTimestamp( $user = null ) {
4750                 global $wgUser, $wgShowUpdatedMarker;
4751                 // Assume current user if none given
4752                 if ( !$user ) {
4753                         $user = $wgUser;
4754                 }
4755                 // Check cache first
4756                 $uid = $user->getId();
4757                 // avoid isset here, as it'll return false for null entries
4758                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4759                         return $this->mNotificationTimestamp[$uid];
4760                 }
4761                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4762                         $this->mNotificationTimestamp[$uid] = false;
4763                         return $this->mNotificationTimestamp[$uid];
4764                 }
4765                 // Don't cache too much!
4766                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4767                         $this->mNotificationTimestamp = array();
4768                 }
4769                 $dbr = wfGetDB( DB_SLAVE );
4770                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4771                         'wl_notificationtimestamp',
4772                         array(
4773                                 'wl_user' => $user->getId(),
4774                                 'wl_namespace' => $this->getNamespace(),
4775                                 'wl_title' => $this->getDBkey(),
4776                         ),
4777                         __METHOD__
4778                 );
4779                 return $this->mNotificationTimestamp[$uid];
4780         }
4781
4782         /**
4783          * Generate strings used for xml 'id' names in monobook tabs
4784          *
4785          * @param string $prepend Defaults to 'nstab-'
4786          * @return string XML 'id' name
4787          */
4788         public function getNamespaceKey( $prepend = 'nstab-' ) {
4789                 global $wgContLang;
4790                 // Gets the subject namespace if this title
4791                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4792                 // Checks if canonical namespace name exists for namespace
4793                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4794                         // Uses canonical namespace name
4795                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4796                 } else {
4797                         // Uses text of namespace
4798                         $namespaceKey = $this->getSubjectNsText();
4799                 }
4800                 // Makes namespace key lowercase
4801                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4802                 // Uses main
4803                 if ( $namespaceKey == '' ) {
4804                         $namespaceKey = 'main';
4805                 }
4806                 // Changes file to image for backwards compatibility
4807                 if ( $namespaceKey == 'file' ) {
4808                         $namespaceKey = 'image';
4809                 }
4810                 return $prepend . $namespaceKey;
4811         }
4812
4813         /**
4814          * Get all extant redirects to this Title
4815          *
4816          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4817          * @return Title[] Array of Title redirects to this title
4818          */
4819         public function getRedirectsHere( $ns = null ) {
4820                 $redirs = array();
4821
4822                 $dbr = wfGetDB( DB_SLAVE );
4823                 $where = array(
4824                         'rd_namespace' => $this->getNamespace(),
4825                         'rd_title' => $this->getDBkey(),
4826                         'rd_from = page_id'
4827                 );
4828                 if ( $this->isExternal() ) {
4829                         $where['rd_interwiki'] = $this->getInterwiki();
4830                 } else {
4831                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4832                 }
4833                 if ( !is_null( $ns ) ) {
4834                         $where['page_namespace'] = $ns;
4835                 }
4836
4837                 $res = $dbr->select(
4838                         array( 'redirect', 'page' ),
4839                         array( 'page_namespace', 'page_title' ),
4840                         $where,
4841                         __METHOD__
4842                 );
4843
4844                 foreach ( $res as $row ) {
4845                         $redirs[] = self::newFromRow( $row );
4846                 }
4847                 return $redirs;
4848         }
4849
4850         /**
4851          * Check if this Title is a valid redirect target
4852          *
4853          * @return bool
4854          */
4855         public function isValidRedirectTarget() {
4856                 global $wgInvalidRedirectTargets;
4857
4858                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4859                 if ( $this->isSpecial( 'Userlogout' ) ) {
4860                         return false;
4861                 }
4862
4863                 foreach ( $wgInvalidRedirectTargets as $target ) {
4864                         if ( $this->isSpecial( $target ) ) {
4865                                 return false;
4866                         }
4867                 }
4868
4869                 return true;
4870         }
4871
4872         /**
4873          * Get a backlink cache object
4874          *
4875          * @return BacklinkCache
4876          */
4877         public function getBacklinkCache() {
4878                 return BacklinkCache::get( $this );
4879         }
4880
4881         /**
4882          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4883          *
4884          * @return bool
4885          */
4886         public function canUseNoindex() {
4887                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4888
4889                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4890                         ? $wgContentNamespaces
4891                         : $wgExemptFromUserRobotsControl;
4892
4893                 return !in_array( $this->mNamespace, $bannedNamespaces );
4894
4895         }
4896
4897         /**
4898          * Returns the raw sort key to be used for categories, with the specified
4899          * prefix.  This will be fed to Collation::getSortKey() to get a
4900          * binary sortkey that can be used for actual sorting.
4901          *
4902          * @param string $prefix The prefix to be used, specified using
4903          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4904          *   prefix.
4905          * @return string
4906          */
4907         public function getCategorySortkey( $prefix = '' ) {
4908                 $unprefixed = $this->getText();
4909
4910                 // Anything that uses this hook should only depend
4911                 // on the Title object passed in, and should probably
4912                 // tell the users to run updateCollations.php --force
4913                 // in order to re-sort existing category relations.
4914                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4915                 if ( $prefix !== '' ) {
4916                         # Separate with a line feed, so the unprefixed part is only used as
4917                         # a tiebreaker when two pages have the exact same prefix.
4918                         # In UCA, tab is the only character that can sort above LF
4919                         # so we strip both of them from the original prefix.
4920                         $prefix = strtr( $prefix, "\n\t", '  ' );
4921                         return "$prefix\n$unprefixed";
4922                 }
4923                 return $unprefixed;
4924         }
4925
4926         /**
4927          * Get the language in which the content of this page is written in
4928          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4929          * e.g. $wgLang (such as special pages, which are in the user language).
4930          *
4931          * @since 1.18
4932          * @return Language
4933          */
4934         public function getPageLanguage() {
4935                 global $wgLang, $wgLanguageCode;
4936                 wfProfileIn( __METHOD__ );
4937                 if ( $this->isSpecialPage() ) {
4938                         // special pages are in the user language
4939                         wfProfileOut( __METHOD__ );
4940                         return $wgLang;
4941                 }
4942
4943                 // Checking if DB language is set
4944                 if ( $this->mDbPageLanguage ) {
4945                         wfProfileOut( __METHOD__ );
4946                         return wfGetLangObj( $this->mDbPageLanguage );
4947                 }
4948
4949                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4950                         // Note that this may depend on user settings, so the cache should
4951                         // be only per-request.
4952                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4953                         // content to determine the page language!
4954                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4955                         // tests.
4956                         $contentHandler = ContentHandler::getForTitle( $this );
4957                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4958                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4959                 } else {
4960                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4961                 }
4962
4963                 wfProfileOut( __METHOD__ );
4964                 return $langObj;
4965         }
4966
4967         /**
4968          * Get the language in which the content of this page is written when
4969          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4970          * e.g. $wgLang (such as special pages, which are in the user language).
4971          *
4972          * @since 1.20
4973          * @return Language
4974          */
4975         public function getPageViewLanguage() {
4976                 global $wgLang;
4977
4978                 if ( $this->isSpecialPage() ) {
4979                         // If the user chooses a variant, the content is actually
4980                         // in a language whose code is the variant code.
4981                         $variant = $wgLang->getPreferredVariant();
4982                         if ( $wgLang->getCode() !== $variant ) {
4983                                 return Language::factory( $variant );
4984                         }
4985
4986                         return $wgLang;
4987                 }
4988
4989                 // @note Can't be cached persistently, depends on user settings.
4990                 // @note ContentHandler::getPageViewLanguage() may need to load the
4991                 //   content to determine the page language!
4992                 $contentHandler = ContentHandler::getForTitle( $this );
4993                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4994                 return $pageLang;
4995         }
4996
4997         /**
4998          * Get a list of rendered edit notices for this page.
4999          *
5000          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
5001          * they will already be wrapped in paragraphs.
5002          *
5003          * @since 1.21
5004          * @param int $oldid Revision ID that's being edited
5005          * @return array
5006          */
5007         public function getEditNotices( $oldid = 0 ) {
5008                 $notices = array();
5009
5010                 # Optional notices on a per-namespace and per-page basis
5011                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
5012                 $editnotice_ns_message = wfMessage( $editnotice_ns );
5013                 if ( $editnotice_ns_message->exists() ) {
5014                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
5015                 }
5016                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
5017                         $parts = explode( '/', $this->getDBkey() );
5018                         $editnotice_base = $editnotice_ns;
5019                         while ( count( $parts ) > 0 ) {
5020                                 $editnotice_base .= '-' . array_shift( $parts );
5021                                 $editnotice_base_msg = wfMessage( $editnotice_base );
5022                                 if ( $editnotice_base_msg->exists() ) {
5023                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
5024                                 }
5025                         }
5026                 } else {
5027                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
5028                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
5029                         $editnoticeMsg = wfMessage( $editnoticeText );
5030                         if ( $editnoticeMsg->exists() ) {
5031                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
5032                         }
5033                 }
5034
5035                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
5036                 return $notices;
5037         }
5038 }