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 string Title fragment (i.e. the bit after the #) */
  78         public $mFragment = '';
  79
  80         /** @var int Article ID, fetched from the link cache on demand */
  81         public $mArticleID = -1;
  82
  83         /** @var bool|int ID of most recent revision */
  84         protected $mLatestID = false;
  85
  86         /**
  87          * @var bool|string ID of the page's content model, i.e. one of the
  88          *   CONTENT_MODEL_XXX constants
  89          */
  90         public $mContentModel = false;
  91
  92         /** @var int Estimated number of revisions; null of not loaded */
  93         private $mEstimateRevisions;
  94
  95         /** @var array Array of groups allowed to edit this article */
  96         public $mRestrictions = array();
  97
  98         /** @var bool  */
  99         protected $mOldRestrictions = false;
 100
 101         /** @var bool Cascade restrictions on this page to included templates and images? */
 102         public $mCascadeRestriction;
 103
 104         /** Caching the results of getCascadeProtectionSources */
 105         public $mCascadingRestrictions;
 106
 107         /** @var array When do the restrictions on this page expire? */
 108         protected $mRestrictionsExpiry = array();
 109
 110         /** @var bool Are cascading restrictions in effect on this page? */
 111         protected $mHasCascadingRestrictions;
 112
 113         /** @var array Where are the cascading restrictions coming from on this page? */
 114         public $mCascadeSources;
 115
 116         /** @var bool Boolean for initialisation on demand */
 117         public $mRestrictionsLoaded = false;
 118
 119         /** @var string Text form including namespace/interwiki, initialised on demand */
 120         protected $mPrefixedText = null;
 121
 122         /** @var mixed Cached value for getTitleProtection (create protection) */
 123         public $mTitleProtection;
 124
 125         /**
 126          * @var int Namespace index when there is no namespace. Don't change the
 127          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 128          *   Zero except in {{transclusion}} tags.
 129          */
 130         public $mDefaultNamespace = NS_MAIN;
 131
 132         /**
 133          * @var bool Is $wgUser watching this page? null if unfilled, accessed
 134          * through userIsWatching()
 135          */
 136         protected $mWatched = null;
 137
 138         /** @var int The page length, 0 for special pages */
 139         protected $mLength = -1;
 140
 141         /** @var null Is the article at this title a redirect? */
 142         public $mRedirect = null;
 143
 144         /** @var array Associative array of user ID -> timestamp/false */
 145         private $mNotificationTimestamp = array();
 146
 147         /** @var bool Whether a page has any subpages */
 148         var $mHasSubpages;
 149
 150         /** @var bool The (string) language code of the page's language and content code. */
 151         private $mPageLanguage = false;
 152
 153         /** @var TitleValue A corresponding TitleValue object */
 154         private $mTitleValue = null;
 155         // @}
 156
 157         /**
 158          * B/C kludge: provide a TitleParser for use by Title.
 159          * Ideally, Title would have no methods that need this.
 160          * Avoid usage of this singleton by using TitleValue
 161          * and the associated services when possible.
 162          *
 163          * @return TitleParser
 164          */
 165         private static function getTitleParser() {
 166                 global $wgContLang, $wgLocalInterwikis;
 167
 168                 static $titleCodec = null;
 169                 static $titleCodecFingerprint = null;
 170
 171                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 172                 // make sure we are using the right one. To detect changes over the course
 173                 // of a request, we remember a fingerprint of the config used to create the
 174                 // codec singleton, and re-create it if the fingerprint doesn't match.
 175                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . join( '+', $wgLocalInterwikis );
 176
 177                 if ( $fingerprint !== $titleCodecFingerprint ) {
 178                         $titleCodec = null;
 179                 }
 180
 181                 if ( !$titleCodec ) {
 182                         $titleCodec = new MediaWikiTitleCodec(
 183                                 $wgContLang,
 184                                 GenderCache::singleton(),
 185                                 $wgLocalInterwikis
 186                         );
 187                         $titleCodecFingerprint = $fingerprint;
 188                 }
 189
 190                 return $titleCodec;
 191         }
 192
 193         /**
 194          * B/C kludge: provide a TitleParser for use by Title.
 195          * Ideally, Title would have no methods that need this.
 196          * Avoid usage of this singleton by using TitleValue
 197          * and the associated services when possible.
 198          *
 199          * @return TitleFormatter
 200          */
 201         private static function getTitleFormatter() {
 202                 //NOTE: we know that getTitleParser() returns a MediaWikiTitleCodec,
 203                 //      which implements TitleFormatter.
 204                 return self::getTitleParser();
 205         }
 206
 207         function __construct() {
 208         }
 209
 210         /**
 211          * Create a new Title from a prefixed DB key
 212          *
 213          * @param string $key The database key, which has underscores
 214          *      instead of spaces, possibly including namespace and
 215          *      interwiki prefixes
 216          * @return Title|null Title, or null on an error
 217          */
 218         public static function newFromDBkey( $key ) {
 219                 $t = new Title();
 220                 $t->mDbkeyform = $key;
 221                 if ( $t->secureAndSplit() ) {
 222                         return $t;
 223                 } else {
 224                         return null;
 225                 }
 226         }
 227
 228         /**
 229          * Create a new Title from a TitleValue
 230          *
 231          * @param TitleValue $titleValue Assumed to be safe.
 232          *
 233          * @return Title
 234          */
 235         public static function newFromTitleValue( TitleValue $titleValue ) {
 236                 return self::makeTitle(
 237                         $titleValue->getNamespace(),
 238                         $titleValue->getText(),
 239                         $titleValue->getFragment() );
 240         }
 241
 242         /**
 243          * Create a new Title from text, such as what one would find in a link. De-
 244          * codes any HTML entities in the text.
 245          *
 246          * @param string $text The link text; spaces, prefixes, and an
 247          *   initial ':' indicating the main namespace are accepted.
 248          * @param int $defaultNamespace The namespace to use if none is specified
 249          *   by a prefix.  If you want to force a specific namespace even if
 250          *   $text might begin with a namespace prefix, use makeTitle() or
 251          *   makeTitleSafe().
 252          * @throws MWException
 253          * @return Title|null Title or null on an error.
 254          */
 255         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 256                 if ( is_object( $text ) ) {
 257                         throw new MWException( 'Title::newFromText given an object' );
 258                 }
 259
 260                 $cache = self::getTitleCache();
 261
 262                 /**
 263                  * Wiki pages often contain multiple links to the same page.
 264                  * Title normalization and parsing can become expensive on
 265                  * pages with many links, so we can save a little time by
 266                  * caching them.
 267                  *
 268                  * In theory these are value objects and won't get changed...
 269                  */
 270                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 271                         return $cache->get( $text );
 272                 }
 273
 274                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 275                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 276
 277                 $t = new Title();
 278                 $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
 279                 $t->mDefaultNamespace = intval( $defaultNamespace );
 280
 281                 if ( $t->secureAndSplit() ) {
 282                         if ( $defaultNamespace == NS_MAIN ) {
 283                                 $cache->set( $text, $t );
 284                         }
 285                         return $t;
 286                 } else {
 287                         return null;
 288                 }
 289         }
 290
 291         /**
 292          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 293          *
 294          * Example of wrong and broken code:
 295          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 296          *
 297          * Example of right code:
 298          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 299          *
 300          * Create a new Title from URL-encoded text. Ensures that
 301          * the given title's length does not exceed the maximum.
 302          *
 303          * @param string $url The title, as might be taken from a URL
 304          * @return Title|null The new object, or null on an error
 305          */
 306         public static function newFromURL( $url ) {
 307                 $t = new Title();
 308
 309                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 310                 # but some URLs used it as a space replacement and they still come
 311                 # from some external search tools.
 312                 if ( strpos( self::legalChars(), '+' ) === false ) {
 313                         $url = str_replace( '+', ' ', $url );
 314                 }
 315
 316                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 317                 if ( $t->secureAndSplit() ) {
 318                         return $t;
 319                 } else {
 320                         return null;
 321                 }
 322         }
 323
 324         /**
 325          * @return MapCacheLRU
 326          */
 327         private static function getTitleCache() {
 328                 if ( self::$titleCache == null ) {
 329                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 330                 }
 331                 return self::$titleCache;
 332         }
 333
 334         /**
 335          * Returns a list of fields that are to be selected for initializing Title
 336          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 337          * whether to include page_content_model.
 338          *
 339          * @return array
 340          */
 341         protected static function getSelectFields() {
 342                 global $wgContentHandlerUseDB;
 343
 344                 $fields = array(
 345                         'page_namespace', 'page_title', 'page_id',
 346                         'page_len', 'page_is_redirect', 'page_latest',
 347                 );
 348
 349                 if ( $wgContentHandlerUseDB ) {
 350                         $fields[] = 'page_content_model';
 351                 }
 352
 353                 return $fields;
 354         }
 355
 356         /**
 357          * Create a new Title from an article ID
 358          *
 359          * @param int $id The page_id corresponding to the Title to create
 360          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 361          * @return Title|null The new object, or null on an error
 362          */
 363         public static function newFromID( $id, $flags = 0 ) {
 364                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 365                 $row = $db->selectRow(
 366                         'page',
 367                         self::getSelectFields(),
 368                         array( 'page_id' => $id ),
 369                         __METHOD__
 370                 );
 371                 if ( $row !== false ) {
 372                         $title = Title::newFromRow( $row );
 373                 } else {
 374                         $title = null;
 375                 }
 376                 return $title;
 377         }
 378
 379         /**
 380          * Make an array of titles from an array of IDs
 381          *
 382          * @param int[] $ids Array of IDs
 383          * @return Title[] Array of Titles
 384          */
 385         public static function newFromIDs( $ids ) {
 386                 if ( !count( $ids ) ) {
 387                         return array();
 388                 }
 389                 $dbr = wfGetDB( DB_SLAVE );
 390
 391                 $res = $dbr->select(
 392                         'page',
 393                         self::getSelectFields(),
 394                         array( 'page_id' => $ids ),
 395                         __METHOD__
 396                 );
 397
 398                 $titles = array();
 399                 foreach ( $res as $row ) {
 400                         $titles[] = Title::newFromRow( $row );
 401                 }
 402                 return $titles;
 403         }
 404
 405         /**
 406          * Make a Title object from a DB row
 407          *
 408          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 409          * @return Title Corresponding Title
 410          */
 411         public static function newFromRow( $row ) {
 412                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 413                 $t->loadFromRow( $row );
 414                 return $t;
 415         }
 416
 417         /**
 418          * Load Title object fields from a DB row.
 419          * If false is given, the title will be treated as non-existing.
 420          *
 421          * @param stdClass|bool $row Database row
 422          */
 423         public function loadFromRow( $row ) {
 424                 if ( $row ) { // page found
 425                         if ( isset( $row->page_id ) ) {
 426                                 $this->mArticleID = (int)$row->page_id;
 427                         }
 428                         if ( isset( $row->page_len ) ) {
 429                                 $this->mLength = (int)$row->page_len;
 430                         }
 431                         if ( isset( $row->page_is_redirect ) ) {
 432                                 $this->mRedirect = (bool)$row->page_is_redirect;
 433                         }
 434                         if ( isset( $row->page_latest ) ) {
 435                                 $this->mLatestID = (int)$row->page_latest;
 436                         }
 437                         if ( isset( $row->page_content_model ) ) {
 438                                 $this->mContentModel = strval( $row->page_content_model );
 439                         } else {
 440                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 441                         }
 442                 } else { // page not found
 443                         $this->mArticleID = 0;
 444                         $this->mLength = 0;
 445                         $this->mRedirect = false;
 446                         $this->mLatestID = 0;
 447                         $this->mContentModel = false; # initialized lazily in getContentModel()
 448                 }
 449         }
 450
 451         /**
 452          * Create a new Title from a namespace index and a DB key.
 453          * It's assumed that $ns and $title are *valid*, for instance when
 454          * they came directly from the database or a special page name.
 455          * For convenience, spaces are converted to underscores so that
 456          * eg user_text fields can be used directly.
 457          *
 458          * @param int $ns The namespace of the article
 459          * @param string $title The unprefixed database key form
 460          * @param string $fragment The link fragment (after the "#")
 461          * @param string $interwiki The interwiki prefix
 462          * @return Title The new object
 463          */
 464         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 465                 $t = new Title();
 466                 $t->mInterwiki = $interwiki;
 467                 $t->mFragment = $fragment;
 468                 $t->mNamespace = $ns = intval( $ns );
 469                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 470                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 471                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 472                 $t->mTextform = str_replace( '_', ' ', $title );
 473                 $t->mContentModel = false; # initialized lazily in getContentModel()
 474                 return $t;
 475         }
 476
 477         /**
 478          * Create a new Title from a namespace index and a DB key.
 479          * The parameters will be checked for validity, which is a bit slower
 480          * than makeTitle() but safer for user-provided data.
 481          *
 482          * @param int $ns The namespace of the article
 483          * @param string $title Database key form
 484          * @param string $fragment The link fragment (after the "#")
 485          * @param string $interwiki Interwiki prefix
 486          * @return Title The new object, or null on an error
 487          */
 488         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 489                 if ( !MWNamespace::exists( $ns ) ) {
 490                         return null;
 491                 }
 492
 493                 $t = new Title();
 494                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 495                 if ( $t->secureAndSplit() ) {
 496                         return $t;
 497                 } else {
 498                         return null;
 499                 }
 500         }
 501
 502         /**
 503          * Create a new Title for the Main Page
 504          *
 505          * @return Title The new object
 506          */
 507         public static function newMainPage() {
 508                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 509                 // Don't give fatal errors if the message is broken
 510                 if ( !$title ) {
 511                         $title = Title::newFromText( 'Main Page' );
 512                 }
 513                 return $title;
 514         }
 515
 516         /**
 517          * Extract a redirect destination from a string and return the
 518          * Title, or null if the text doesn't contain a valid redirect
 519          * This will only return the very next target, useful for
 520          * the redirect table and other checks that don't need full recursion
 521          *
 522          * @param string $text Text with possible redirect
 523          * @return Title The corresponding Title
 524          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 525          */
 526         public static function newFromRedirect( $text ) {
 527                 ContentHandler::deprecated( __METHOD__, '1.21' );
 528
 529                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 530                 return $content->getRedirectTarget();
 531         }
 532
 533         /**
 534          * Extract a redirect destination from a string and return the
 535          * Title, or null if the text doesn't contain a valid redirect
 536          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 537          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 538          *
 539          * @param string $text Text with possible redirect
 540          * @return Title
 541          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 542          */
 543         public static function newFromRedirectRecurse( $text ) {
 544                 ContentHandler::deprecated( __METHOD__, '1.21' );
 545
 546                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 547                 return $content->getUltimateRedirectTarget();
 548         }
 549
 550         /**
 551          * Extract a redirect destination from a string and return an
 552          * array of Titles, or null if the text doesn't contain a valid redirect
 553          * The last element in the array is the final destination after all redirects
 554          * have been resolved (up to $wgMaxRedirects times)
 555          *
 556          * @param string $text Text with possible redirect
 557          * @return Title[] Array of Titles, with the destination last
 558          * @deprecated since 1.21, use Content::getRedirectChain instead.
 559          */
 560         public static function newFromRedirectArray( $text ) {
 561                 ContentHandler::deprecated( __METHOD__, '1.21' );
 562
 563                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 564                 return $content->getRedirectChain();
 565         }
 566
 567         /**
 568          * Get the prefixed DB key associated with an ID
 569          *
 570          * @param int $id The page_id of the article
 571          * @return Title|null An object representing the article, or null if no such article was found
 572          */
 573         public static function nameOf( $id ) {
 574                 $dbr = wfGetDB( DB_SLAVE );
 575
 576                 $s = $dbr->selectRow(
 577                         'page',
 578                         array( 'page_namespace', 'page_title' ),
 579                         array( 'page_id' => $id ),
 580                         __METHOD__
 581                 );
 582                 if ( $s === false ) {
 583                         return null;
 584                 }
 585
 586                 $n = self::makeName( $s->page_namespace, $s->page_title );
 587                 return $n;
 588         }
 589
 590         /**
 591          * Get a regex character class describing the legal characters in a link
 592          *
 593          * @return string The list of characters, not delimited
 594          */
 595         public static function legalChars() {
 596                 global $wgLegalTitleChars;
 597                 return $wgLegalTitleChars;
 598         }
 599
 600         /**
 601          * Returns a simple regex that will match on characters and sequences invalid in titles.
 602          * Note that this doesn't pick up many things that could be wrong with titles, but that
 603          * replacing this regex with something valid will make many titles valid.
 604          *
 605          * @todo: move this into MediaWikiTitleCodec
 606          *
 607          * @return string Regex string
 608          */
 609         static function getTitleInvalidRegex() {
 610                 static $rxTc = false;
 611                 if ( !$rxTc ) {
 612                         # Matching titles will be held as illegal.
 613                         $rxTc = '/' .
 614                                 # Any character not allowed is forbidden...
 615                                 '[^' . self::legalChars() . ']' .
 616                                 # URL percent encoding sequences interfere with the ability
 617                                 # to round-trip titles -- you can't link to them consistently.
 618                                 '|%[0-9A-Fa-f]{2}' .
 619                                 # XML/HTML character references produce similar issues.
 620                                 '|&[A-Za-z0-9\x80-\xff]+;' .
 621                                 '|&#[0-9]+;' .
 622                                 '|&#x[0-9A-Fa-f]+;' .
 623                                 '/S';
 624                 }
 625
 626                 return $rxTc;
 627         }
 628
 629         /**
 630          * Utility method for converting a character sequence from bytes to Unicode.
 631          *
 632          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 633          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 634          *
 635          * @param string $byteClass
 636          * @return string
 637          */
 638         public static function convertByteClassToUnicodeClass( $byteClass ) {
 639                 $length = strlen( $byteClass );
 640                 // Input token queue
 641                 $x0 = $x1 = $x2 = '';
 642                 // Decoded queue
 643                 $d0 = $d1 = $d2 = '';
 644                 // Decoded integer codepoints
 645                 $ord0 = $ord1 = $ord2 = 0;
 646                 // Re-encoded queue
 647                 $r0 = $r1 = $r2 = '';
 648                 // Output
 649                 $out = '';
 650                 // Flags
 651                 $allowUnicode = false;
 652                 for ( $pos = 0; $pos < $length; $pos++ ) {
 653                         // Shift the queues down
 654                         $x2 = $x1;
 655                         $x1 = $x0;
 656                         $d2 = $d1;
 657                         $d1 = $d0;
 658                         $ord2 = $ord1;
 659                         $ord1 = $ord0;
 660                         $r2 = $r1;
 661                         $r1 = $r0;
 662                         // Load the current input token and decoded values
 663                         $inChar = $byteClass[$pos];
 664                         if ( $inChar == '\\' ) {
 665                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 666                                         $x0 = $inChar . $m[0];
 667                                         $d0 = chr( hexdec( $m[1] ) );
 668                                         $pos += strlen( $m[0] );
 669                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 670                                         $x0 = $inChar . $m[0];
 671                                         $d0 = chr( octdec( $m[0] ) );
 672                                         $pos += strlen( $m[0] );
 673                                 } elseif ( $pos + 1 >= $length ) {
 674                                         $x0 = $d0 = '\\';
 675                                 } else {
 676                                         $d0 = $byteClass[$pos + 1];
 677                                         $x0 = $inChar . $d0;
 678                                         $pos += 1;
 679                                 }
 680                         } else {
 681                                 $x0 = $d0 = $inChar;
 682                         }
 683                         $ord0 = ord( $d0 );
 684                         // Load the current re-encoded value
 685                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 686                                 $r0 = sprintf( '\x%02x', $ord0 );
 687                         } elseif ( $ord0 >= 0x80 ) {
 688                                 // Allow unicode if a single high-bit character appears
 689                                 $r0 = sprintf( '\x%02x', $ord0 );
 690                                 $allowUnicode = true;
 691                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 692                                 $r0 = '\\' . $d0;
 693                         } else {
 694                                 $r0 = $d0;
 695                         }
 696                         // Do the output
 697                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 698                                 // Range
 699                                 if ( $ord2 > $ord0 ) {
 700                                         // Empty range
 701                                 } elseif ( $ord0 >= 0x80 ) {
 702                                         // Unicode range
 703                                         $allowUnicode = true;
 704                                         if ( $ord2 < 0x80 ) {
 705                                                 // Keep the non-unicode section of the range
 706                                                 $out .= "$r2-\\x7F";
 707                                         }
 708                                 } else {
 709                                         // Normal range
 710                                         $out .= "$r2-$r0";
 711                                 }
 712                                 // Reset state to the initial value
 713                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 714                         } elseif ( $ord2 < 0x80 ) {
 715                                 // ASCII character
 716                                 $out .= $r2;
 717                         }
 718                 }
 719                 if ( $ord1 < 0x80 ) {
 720                         $out .= $r1;
 721                 }
 722                 if ( $ord0 < 0x80 ) {
 723                         $out .= $r0;
 724                 }
 725                 if ( $allowUnicode ) {
 726                         $out .= '\u0080-\uFFFF';
 727                 }
 728                 return $out;
 729         }
 730
 731         /**
 732          * Make a prefixed DB key from a DB key and a namespace index
 733          *
 734          * @param int $ns Numerical representation of the namespace
 735          * @param string $title The DB key form the title
 736          * @param string $fragment The link fragment (after the "#")
 737          * @param string $interwiki The interwiki prefix
 738          * @return string The prefixed form of the title
 739          */
 740         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 741                 global $wgContLang;
 742
 743                 $namespace = $wgContLang->getNsText( $ns );
 744                 $name = $namespace == '' ? $title : "$namespace:$title";
 745                 if ( strval( $interwiki ) != '' ) {
 746                         $name = "$interwiki:$name";
 747                 }
 748                 if ( strval( $fragment ) != '' ) {
 749                         $name .= '#' . $fragment;
 750                 }
 751                 return $name;
 752         }
 753
 754         /**
 755          * Escape a text fragment, say from a link, for a URL
 756          *
 757          * @param string $fragment Containing a URL or link fragment (after the "#")
 758          * @return string Escaped string
 759          */
 760         static function escapeFragmentForURL( $fragment ) {
 761                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 762                 # fragments appear not to work in IE (at least up to 7) or in at least
 763                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 764                 # to care if they aren't encoded.
 765                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 766         }
 767
 768         /**
 769          * Callback for usort() to do title sorts by (namespace, title)
 770          *
 771          * @param Title $a
 772          * @param Title $b
 773          *
 774          * @return int Result of string comparison, or namespace comparison
 775          */
 776         public static function compare( $a, $b ) {
 777                 if ( $a->getNamespace() == $b->getNamespace() ) {
 778                         return strcmp( $a->getText(), $b->getText() );
 779                 } else {
 780                         return $a->getNamespace() - $b->getNamespace();
 781                 }
 782         }
 783
 784         /**
 785          * Determine whether the object refers to a page within
 786          * this project.
 787          *
 788          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 789          */
 790         public function isLocal() {
 791                 if ( $this->isExternal() ) {
 792                         $iw = Interwiki::fetch( $this->mInterwiki );
 793                         if ( $iw ) {
 794                                 return $iw->isLocal();
 795                         }
 796                 }
 797                 return true;
 798         }
 799
 800         /**
 801          * Is this Title interwiki?
 802          *
 803          * @return bool
 804          */
 805         public function isExternal() {
 806                 return $this->mInterwiki !== '';
 807         }
 808
 809         /**
 810          * Get the interwiki prefix
 811          *
 812          * Use Title::isExternal to check if a interwiki is set
 813          *
 814          * @return string Interwiki prefix
 815          */
 816         public function getInterwiki() {
 817                 return $this->mInterwiki;
 818         }
 819
 820         /**
 821          * Determine whether the object refers to a page within
 822          * this project and is transcludable.
 823          *
 824          * @return bool True if this is transcludable
 825          */
 826         public function isTrans() {
 827                 if ( !$this->isExternal() ) {
 828                         return false;
 829                 }
 830
 831                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 832         }
 833
 834         /**
 835          * Returns the DB name of the distant wiki which owns the object.
 836          *
 837          * @return string The DB name
 838          */
 839         public function getTransWikiID() {
 840                 if ( !$this->isExternal() ) {
 841                         return false;
 842                 }
 843
 844                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 845         }
 846
 847         /**
 848          * Get a TitleValue object representing this Title.
 849          *
 850          * @note: Not all valid Titles have a corresponding valid TitleValue
 851          * (e.g. TitleValues cannot represent page-local links that have a
 852          * fragment but no title text).
 853          *
 854          * @return TitleValue|null
 855          */
 856         public function getTitleValue() {
 857                 if ( $this->mTitleValue === null ) {
 858                         try {
 859                                 $this->mTitleValue = new TitleValue(
 860                                         $this->getNamespace(),
 861                                         $this->getDBkey(),
 862                                         $this->getFragment() );
 863                         } catch ( InvalidArgumentException $ex ) {
 864                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 865                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 866                         }
 867                 }
 868
 869                 return $this->mTitleValue;
 870         }
 871
 872         /**
 873          * Get the text form (spaces not underscores) of the main part
 874          *
 875          * @return string Main part of the title
 876          */
 877         public function getText() {
 878                 return $this->mTextform;
 879         }
 880
 881         /**
 882          * Get the URL-encoded form of the main part
 883          *
 884          * @return string Main part of the title, URL-encoded
 885          */
 886         public function getPartialURL() {
 887                 return $this->mUrlform;
 888         }
 889
 890         /**
 891          * Get the main part with underscores
 892          *
 893          * @return string Main part of the title, with underscores
 894          */
 895         public function getDBkey() {
 896                 return $this->mDbkeyform;
 897         }
 898
 899         /**
 900          * Get the DB key with the initial letter case as specified by the user
 901          *
 902          * @return string DB key
 903          */
 904         function getUserCaseDBKey() {
 905                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 906                         return $this->mUserCaseDBKey;
 907                 } else {
 908                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 909                         return $this->mDbkeyform;
 910                 }
 911         }
 912
 913         /**
 914          * Get the namespace index, i.e. one of the NS_xxxx constants.
 915          *
 916          * @return int Namespace index
 917          */
 918         public function getNamespace() {
 919                 return $this->mNamespace;
 920         }
 921
 922         /**
 923          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 924          *
 925          * @throws MWException
 926          * @return string Content model id
 927          */
 928         public function getContentModel() {
 929                 if ( !$this->mContentModel ) {
 930                         $linkCache = LinkCache::singleton();
 931                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 932                 }
 933
 934                 if ( !$this->mContentModel ) {
 935                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 936                 }
 937
 938                 if ( !$this->mContentModel ) {
 939                         throw new MWException( 'Failed to determine content model!' );
 940                 }
 941
 942                 return $this->mContentModel;
 943         }
 944
 945         /**
 946          * Convenience method for checking a title's content model name
 947          *
 948          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 949          * @return bool True if $this->getContentModel() == $id
 950          */
 951         public function hasContentModel( $id ) {
 952                 return $this->getContentModel() == $id;
 953         }
 954
 955         /**
 956          * Get the namespace text
 957          *
 958          * @return string Namespace text
 959          */
 960         public function getNsText() {
 961                 if ( $this->isExternal() ) {
 962                         // This probably shouldn't even happen. ohh man, oh yuck.
 963                         // But for interwiki transclusion it sometimes does.
 964                         // Shit. Shit shit shit.
 965                         //
 966                         // Use the canonical namespaces if possible to try to
 967                         // resolve a foreign namespace.
 968                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 969                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 970                         }
 971                 }
 972
 973                 try {
 974                         $formatter = $this->getTitleFormatter();
 975                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 976                 } catch ( InvalidArgumentException $ex )  {
 977                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 978                         return false;
 979                 }
 980         }
 981
 982         /**
 983          * Get the namespace text of the subject (rather than talk) page
 984          *
 985          * @return string Namespace text
 986          */
 987         public function getSubjectNsText() {
 988                 global $wgContLang;
 989                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 990         }
 991
 992         /**
 993          * Get the namespace text of the talk page
 994          *
 995          * @return string Namespace text
 996          */
 997         public function getTalkNsText() {
 998                 global $wgContLang;
 999                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1000         }
1001
1002         /**
1003          * Could this title have a corresponding talk page?
1004          *
1005          * @return bool
1006          */
1007         public function canTalk() {
1008                 return MWNamespace::canTalk( $this->mNamespace );
1009         }
1010
1011         /**
1012          * Is this in a namespace that allows actual pages?
1013          *
1014          * @return bool
1015          * @internal note -- uses hardcoded namespace index instead of constants
1016          */
1017         public function canExist() {
1018                 return $this->mNamespace >= NS_MAIN;
1019         }
1020
1021         /**
1022          * Can this title be added to a user's watchlist?
1023          *
1024          * @return bool
1025          */
1026         public function isWatchable() {
1027                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1028         }
1029
1030         /**
1031          * Returns true if this is a special page.
1032          *
1033          * @return bool
1034          */
1035         public function isSpecialPage() {
1036                 return $this->getNamespace() == NS_SPECIAL;
1037         }
1038
1039         /**
1040          * Returns true if this title resolves to the named special page
1041          *
1042          * @param string $name The special page name
1043          * @return bool
1044          */
1045         public function isSpecial( $name ) {
1046                 if ( $this->isSpecialPage() ) {
1047                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1048                         if ( $name == $thisName ) {
1049                                 return true;
1050                         }
1051                 }
1052                 return false;
1053         }
1054
1055         /**
1056          * If the Title refers to a special page alias which is not the local default, resolve
1057          * the alias, and localise the name as necessary.  Otherwise, return $this
1058          *
1059          * @return Title
1060          */
1061         public function fixSpecialName() {
1062                 if ( $this->isSpecialPage() ) {
1063                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1064                         if ( $canonicalName ) {
1065                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1066                                 if ( $localName != $this->mDbkeyform ) {
1067                                         return Title::makeTitle( NS_SPECIAL, $localName );
1068                                 }
1069                         }
1070                 }
1071                 return $this;
1072         }
1073
1074         /**
1075          * Returns true if the title is inside the specified namespace.
1076          *
1077          * Please make use of this instead of comparing to getNamespace()
1078          * This function is much more resistant to changes we may make
1079          * to namespaces than code that makes direct comparisons.
1080          * @param int $ns The namespace
1081          * @return bool
1082          * @since 1.19
1083          */
1084         public function inNamespace( $ns ) {
1085                 return MWNamespace::equals( $this->getNamespace(), $ns );
1086         }
1087
1088         /**
1089          * Returns true if the title is inside one of the specified namespaces.
1090          *
1091          * @param ...$namespaces The namespaces to check for
1092          * @return bool
1093          * @since 1.19
1094          */
1095         public function inNamespaces( /* ... */ ) {
1096                 $namespaces = func_get_args();
1097                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1098                         $namespaces = $namespaces[0];
1099                 }
1100
1101                 foreach ( $namespaces as $ns ) {
1102                         if ( $this->inNamespace( $ns ) ) {
1103                                 return true;
1104                         }
1105                 }
1106
1107                 return false;
1108         }
1109
1110         /**
1111          * Returns true if the title has the same subject namespace as the
1112          * namespace specified.
1113          * For example this method will take NS_USER and return true if namespace
1114          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1115          * as their subject namespace.
1116          *
1117          * This is MUCH simpler than individually testing for equivalence
1118          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1119          * @since 1.19
1120          * @param int $ns
1121          * @return bool
1122          */
1123         public function hasSubjectNamespace( $ns ) {
1124                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1125         }
1126
1127         /**
1128          * Is this Title in a namespace which contains content?
1129          * In other words, is this a content page, for the purposes of calculating
1130          * statistics, etc?
1131          *
1132          * @return bool
1133          */
1134         public function isContentPage() {
1135                 return MWNamespace::isContent( $this->getNamespace() );
1136         }
1137
1138         /**
1139          * Would anybody with sufficient privileges be able to move this page?
1140          * Some pages just aren't movable.
1141          *
1142          * @return bool
1143          */
1144         public function isMovable() {
1145                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1146                         // Interwiki title or immovable namespace. Hooks don't get to override here
1147                         return false;
1148                 }
1149
1150                 $result = true;
1151                 wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
1152                 return $result;
1153         }
1154
1155         /**
1156          * Is this the mainpage?
1157          * @note Title::newFromText seems to be sufficiently optimized by the title
1158          * cache that we don't need to over-optimize by doing direct comparisons and
1159          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1160          * ends up reporting something differently than $title->isMainPage();
1161          *
1162          * @since 1.18
1163          * @return bool
1164          */
1165         public function isMainPage() {
1166                 return $this->equals( Title::newMainPage() );
1167         }
1168
1169         /**
1170          * Is this a subpage?
1171          *
1172          * @return bool
1173          */
1174         public function isSubpage() {
1175                 return MWNamespace::hasSubpages( $this->mNamespace )
1176                         ? strpos( $this->getText(), '/' ) !== false
1177                         : false;
1178         }
1179
1180         /**
1181          * Is this a conversion table for the LanguageConverter?
1182          *
1183          * @return bool
1184          */
1185         public function isConversionTable() {
1186                 // @todo ConversionTable should become a separate content model.
1187
1188                 return $this->getNamespace() == NS_MEDIAWIKI &&
1189                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1190         }
1191
1192         /**
1193          * Does that page contain wikitext, or it is JS, CSS or whatever?
1194          *
1195          * @return bool
1196          */
1197         public function isWikitextPage() {
1198                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1199         }
1200
1201         /**
1202          * Could this page contain custom CSS or JavaScript for the global UI.
1203          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1204          * or CONTENT_MODEL_JAVASCRIPT.
1205          *
1206          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1207          * for that!
1208          *
1209          * Note that this method should not return true for pages that contain and
1210          * show "inactive" CSS or JS.
1211          *
1212          * @return bool
1213          */
1214         public function isCssOrJsPage() {
1215                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1216                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1217                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1218
1219                 # @note This hook is also called in ContentHandler::getDefaultModel.
1220                 #   It's called here again to make sure hook functions can force this
1221                 #   method to return true even outside the mediawiki namespace.
1222
1223                 wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ) );
1224
1225                 return $isCssOrJsPage;
1226         }
1227
1228         /**
1229          * Is this a .css or .js subpage of a user page?
1230          * @return bool
1231          */
1232         public function isCssJsSubpage() {
1233                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1234                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1235                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1236         }
1237
1238         /**
1239          * Trim down a .css or .js subpage title to get the corresponding skin name
1240          *
1241          * @return string Containing skin name from .css or .js subpage title
1242          */
1243         public function getSkinFromCssJsSubpage() {
1244                 $subpage = explode( '/', $this->mTextform );
1245                 $subpage = $subpage[count( $subpage ) - 1];
1246                 $lastdot = strrpos( $subpage, '.' );
1247                 if ( $lastdot === false ) {
1248                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1249                 }
1250                 return substr( $subpage, 0, $lastdot );
1251         }
1252
1253         /**
1254          * Is this a .css subpage of a user page?
1255          *
1256          * @return bool
1257          */
1258         public function isCssSubpage() {
1259                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1260                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1261         }
1262
1263         /**
1264          * Is this a .js subpage of a user page?
1265          *
1266          * @return bool
1267          */
1268         public function isJsSubpage() {
1269                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1270                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1271         }
1272
1273         /**
1274          * Is this a talk page of some sort?
1275          *
1276          * @return bool
1277          */
1278         public function isTalkPage() {
1279                 return MWNamespace::isTalk( $this->getNamespace() );
1280         }
1281
1282         /**
1283          * Get a Title object associated with the talk page of this article
1284          *
1285          * @return Title The object for the talk page
1286          */
1287         public function getTalkPage() {
1288                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1289         }
1290
1291         /**
1292          * Get a title object associated with the subject page of this
1293          * talk page
1294          *
1295          * @return Title The object for the subject page
1296          */
1297         public function getSubjectPage() {
1298                 // Is this the same title?
1299                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1300                 if ( $this->getNamespace() == $subjectNS ) {
1301                         return $this;
1302                 }
1303                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1304         }
1305
1306         /**
1307          * Get the default namespace index, for when there is no namespace
1308          *
1309          * @return int Default namespace index
1310          */
1311         public function getDefaultNamespace() {
1312                 return $this->mDefaultNamespace;
1313         }
1314
1315         /**
1316          * Get the Title fragment (i.e.\ the bit after the #) in text form
1317          *
1318          * Use Title::hasFragment to check for a fragment
1319          *
1320          * @return string Title fragment
1321          */
1322         public function getFragment() {
1323                 return $this->mFragment;
1324         }
1325
1326         /**
1327          * Check if a Title fragment is set
1328          *
1329          * @return bool
1330          * @since 1.23
1331          */
1332         public function hasFragment() {
1333                 return $this->mFragment !== '';
1334         }
1335
1336         /**
1337          * Get the fragment in URL form, including the "#" character if there is one
1338          * @return string Fragment in URL form
1339          */
1340         public function getFragmentForURL() {
1341                 if ( !$this->hasFragment() ) {
1342                         return '';
1343                 } else {
1344                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1345                 }
1346         }
1347
1348         /**
1349          * Set the fragment for this title. Removes the first character from the
1350          * specified fragment before setting, so it assumes you're passing it with
1351          * an initial "#".
1352          *
1353          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1354          * Still in active use privately.
1355          *
1356          * @param string $fragment Text
1357          */
1358         public function setFragment( $fragment ) {
1359                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1360         }
1361
1362         /**
1363          * Prefix some arbitrary text with the namespace or interwiki prefix
1364          * of this object
1365          *
1366          * @param string $name The text
1367          * @return string The prefixed text
1368          * @private
1369          */
1370         private function prefix( $name ) {
1371                 $p = '';
1372                 if ( $this->isExternal() ) {
1373                         $p = $this->mInterwiki . ':';
1374                 }
1375
1376                 if ( 0 != $this->mNamespace ) {
1377                         $p .= $this->getNsText() . ':';
1378                 }
1379                 return $p . $name;
1380         }
1381
1382         /**
1383          * Get the prefixed database key form
1384          *
1385          * @return string The prefixed title, with underscores and
1386          *  any interwiki and namespace prefixes
1387          */
1388         public function getPrefixedDBkey() {
1389                 $s = $this->prefix( $this->mDbkeyform );
1390                 $s = str_replace( ' ', '_', $s );
1391                 return $s;
1392         }
1393
1394         /**
1395          * Get the prefixed title with spaces.
1396          * This is the form usually used for display
1397          *
1398          * @return string The prefixed title, with spaces
1399          */
1400         public function getPrefixedText() {
1401                 if ( $this->mPrefixedText === null ) {
1402                         $s = $this->prefix( $this->mTextform );
1403                         $s = str_replace( '_', ' ', $s );
1404                         $this->mPrefixedText = $s;
1405                 }
1406                 return $this->mPrefixedText;
1407         }
1408
1409         /**
1410          * Return a string representation of this title
1411          *
1412          * @return string Representation of this title
1413          */
1414         public function __toString() {
1415                 return $this->getPrefixedText();
1416         }
1417
1418         /**
1419          * Get the prefixed title with spaces, plus any fragment
1420          * (part beginning with '#')
1421          *
1422          * @return string The prefixed title, with spaces and the fragment, including '#'
1423          */
1424         public function getFullText() {
1425                 $text = $this->getPrefixedText();
1426                 if ( $this->hasFragment() ) {
1427                         $text .= '#' . $this->getFragment();
1428                 }
1429                 return $text;
1430         }
1431
1432         /**
1433          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1434          *
1435          * @par Example:
1436          * @code
1437          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1438          * # returns: 'Foo'
1439          * @endcode
1440          *
1441          * @return string Root name
1442          * @since 1.20
1443          */
1444         public function getRootText() {
1445                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1446                         return $this->getText();
1447                 }
1448
1449                 return strtok( $this->getText(), '/' );
1450         }
1451
1452         /**
1453          * Get the root page name title, i.e. the leftmost part before any slashes
1454          *
1455          * @par Example:
1456          * @code
1457          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1458          * # returns: Title{User:Foo}
1459          * @endcode
1460          *
1461          * @return Title Root title
1462          * @since 1.20
1463          */
1464         public function getRootTitle() {
1465                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1466         }
1467
1468         /**
1469          * Get the base page name without a namespace, i.e. the part before the subpage name
1470          *
1471          * @par Example:
1472          * @code
1473          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1474          * # returns: 'Foo/Bar'
1475          * @endcode
1476          *
1477          * @return string Base name
1478          */
1479         public function getBaseText() {
1480                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1481                         return $this->getText();
1482                 }
1483
1484                 $parts = explode( '/', $this->getText() );
1485                 # Don't discard the real title if there's no subpage involved
1486                 if ( count( $parts ) > 1 ) {
1487                         unset( $parts[count( $parts ) - 1] );
1488                 }
1489                 return implode( '/', $parts );
1490         }
1491
1492         /**
1493          * Get the base page name title, i.e. the part before the subpage name
1494          *
1495          * @par Example:
1496          * @code
1497          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1498          * # returns: Title{User:Foo/Bar}
1499          * @endcode
1500          *
1501          * @return Title Base title
1502          * @since 1.20
1503          */
1504         public function getBaseTitle() {
1505                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1506         }
1507
1508         /**
1509          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1510          *
1511          * @par Example:
1512          * @code
1513          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1514          * # returns: "Baz"
1515          * @endcode
1516          *
1517          * @return string Subpage name
1518          */
1519         public function getSubpageText() {
1520                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1521                         return $this->mTextform;
1522                 }
1523                 $parts = explode( '/', $this->mTextform );
1524                 return $parts[count( $parts ) - 1];
1525         }
1526
1527         /**
1528          * Get the title for a subpage of the current page
1529          *
1530          * @par Example:
1531          * @code
1532          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1533          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1534          * @endcode
1535          *
1536          * @param string $text The subpage name to add to the title
1537          * @return Title Subpage title
1538          * @since 1.20
1539          */
1540         public function getSubpage( $text ) {
1541                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1542         }
1543
1544         /**
1545          * Get the HTML-escaped displayable text form.
1546          * Used for the title field in <a> tags.
1547          *
1548          * @return string The text, including any prefixes
1549          * @deprecated since 1.19
1550          */
1551         public function getEscapedText() {
1552                 wfDeprecated( __METHOD__, '1.19' );
1553                 return htmlspecialchars( $this->getPrefixedText() );
1554         }
1555
1556         /**
1557          * Get a URL-encoded form of the subpage text
1558          *
1559          * @return string URL-encoded subpage name
1560          */
1561         public function getSubpageUrlForm() {
1562                 $text = $this->getSubpageText();
1563                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1564                 return $text;
1565         }
1566
1567         /**
1568          * Get a URL-encoded title (not an actual URL) including interwiki
1569          *
1570          * @return string The URL-encoded form
1571          */
1572         public function getPrefixedURL() {
1573                 $s = $this->prefix( $this->mDbkeyform );
1574                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1575                 return $s;
1576         }
1577
1578         /**
1579          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1580          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1581          * second argument named variant. This was deprecated in favor
1582          * of passing an array of option with a "variant" key
1583          * Once $query2 is removed for good, this helper can be dropped
1584          * and the wfArrayToCgi moved to getLocalURL();
1585          *
1586          * @since 1.19 (r105919)
1587          * @param array|string $query
1588          * @param bool $query2
1589          * @return string
1590          */
1591         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1592                 if ( $query2 !== false ) {
1593                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1594                                 "method called with a second parameter is deprecated. Add your " .
1595                                 "parameter to an array passed as the first parameter.", "1.19" );
1596                 }
1597                 if ( is_array( $query ) ) {
1598                         $query = wfArrayToCgi( $query );
1599                 }
1600                 if ( $query2 ) {
1601                         if ( is_string( $query2 ) ) {
1602                                 // $query2 is a string, we will consider this to be
1603                                 // a deprecated $variant argument and add it to the query
1604                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1605                         } else {
1606                                 $query2 = wfArrayToCgi( $query2 );
1607                         }
1608                         // If we have $query content add a & to it first
1609                         if ( $query ) {
1610                                 $query .= '&';
1611                         }
1612                         // Now append the queries together
1613                         $query .= $query2;
1614                 }
1615                 return $query;
1616         }
1617
1618         /**
1619          * Get a real URL referring to this title, with interwiki link and
1620          * fragment
1621          *
1622          * @see self::getLocalURL for the arguments.
1623          * @see wfExpandUrl
1624          * @param array|string $query
1625          * @param bool $query2
1626          * @param string $proto Protocol type to use in URL
1627          * @return string The URL
1628          */
1629         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1630                 $query = self::fixUrlQueryArgs( $query, $query2 );
1631
1632                 # Hand off all the decisions on urls to getLocalURL
1633                 $url = $this->getLocalURL( $query );
1634
1635                 # Expand the url to make it a full url. Note that getLocalURL has the
1636                 # potential to output full urls for a variety of reasons, so we use
1637                 # wfExpandUrl instead of simply prepending $wgServer
1638                 $url = wfExpandUrl( $url, $proto );
1639
1640                 # Finally, add the fragment.
1641                 $url .= $this->getFragmentForURL();
1642
1643                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1644                 return $url;
1645         }
1646
1647         /**
1648          * Get a URL with no fragment or server name (relative URL) from a Title object.
1649          * If this page is generated with action=render, however,
1650          * $wgServer is prepended to make an absolute URL.
1651          *
1652          * @see self::getFullURL to always get an absolute URL.
1653          * @see self::newFromText to produce a Title object.
1654          *
1655          * @param string|array $query an optional query string,
1656          *   not used for interwiki links. Can be specified as an associative array as well,
1657          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1658          *   Some query patterns will trigger various shorturl path replacements.
1659          * @param array $query2 An optional secondary query array. This one MUST
1660          *   be an array. If a string is passed it will be interpreted as a deprecated
1661          *   variant argument and urlencoded into a variant= argument.
1662          *   This second query argument will be added to the $query
1663          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1664          *   pair in the first parameter array instead.
1665          *
1666          * @return string String of the URL.
1667          */
1668         public function getLocalURL( $query = '', $query2 = false ) {
1669                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1670
1671                 $query = self::fixUrlQueryArgs( $query, $query2 );
1672
1673                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1674                 if ( $interwiki ) {
1675                         $namespace = $this->getNsText();
1676                         if ( $namespace != '' ) {
1677                                 # Can this actually happen? Interwikis shouldn't be parsed.
1678                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1679                                 $namespace .= ':';
1680                         }
1681                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1682                         $url = wfAppendQuery( $url, $query );
1683                 } else {
1684                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1685                         if ( $query == '' ) {
1686                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1687                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1688                         } else {
1689                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1690                                 $url = false;
1691                                 $matches = array();
1692
1693                                 if ( !empty( $wgActionPaths )
1694                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1695                                 ) {
1696                                         $action = urldecode( $matches[2] );
1697                                         if ( isset( $wgActionPaths[$action] ) ) {
1698                                                 $query = $matches[1];
1699                                                 if ( isset( $matches[4] ) ) {
1700                                                         $query .= $matches[4];
1701                                                 }
1702                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1703                                                 if ( $query != '' ) {
1704                                                         $url = wfAppendQuery( $url, $query );
1705                                                 }
1706                                         }
1707                                 }
1708
1709                                 if ( $url === false
1710                                         && $wgVariantArticlePath
1711                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1712                                         && $this->getPageLanguage()->hasVariants()
1713                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1714                                 ) {
1715                                         $variant = urldecode( $matches[1] );
1716                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1717                                                 // Only do the variant replacement if the given variant is a valid
1718                                                 // variant for the page's language.
1719                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1720                                                 $url = str_replace( '$1', $dbkey, $url );
1721                                         }
1722                                 }
1723
1724                                 if ( $url === false ) {
1725                                         if ( $query == '-' ) {
1726                                                 $query = '';
1727                                         }
1728                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1729                                 }
1730                         }
1731
1732                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1733
1734                         // @todo FIXME: This causes breakage in various places when we
1735                         // actually expected a local URL and end up with dupe prefixes.
1736                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1737                                 $url = $wgServer . $url;
1738                         }
1739                 }
1740                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1741                 return $url;
1742         }
1743
1744         /**
1745          * Get a URL that's the simplest URL that will be valid to link, locally,
1746          * to the current Title.  It includes the fragment, but does not include
1747          * the server unless action=render is used (or the link is external).  If
1748          * there's a fragment but the prefixed text is empty, we just return a link
1749          * to the fragment.
1750          *
1751          * The result obviously should not be URL-escaped, but does need to be
1752          * HTML-escaped if it's being output in HTML.
1753          *
1754          * @param array $query
1755          * @param bool $query2
1756          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1757          * @see self::getLocalURL for the arguments.
1758          * @return string The URL
1759          */
1760         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1761                 wfProfileIn( __METHOD__ );
1762                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1763                         $ret = $this->getFullURL( $query, $query2, $proto );
1764                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1765                         $ret = $this->getFragmentForURL();
1766                 } else {
1767                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1768                 }
1769                 wfProfileOut( __METHOD__ );
1770                 return $ret;
1771         }
1772
1773         /**
1774          * Get an HTML-escaped version of the URL form, suitable for
1775          * using in a link, without a server name or fragment
1776          *
1777          * @see self::getLocalURL for the arguments.
1778          * @param string $query
1779          * @param bool|string $query2
1780          * @return string The URL
1781          * @deprecated since 1.19
1782          */
1783         public function escapeLocalURL( $query = '', $query2 = false ) {
1784                 wfDeprecated( __METHOD__, '1.19' );
1785                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1786         }
1787
1788         /**
1789          * Get an HTML-escaped version of the URL form, suitable for
1790          * using in a link, including the server name and fragment
1791          *
1792          * @see self::getLocalURL for the arguments.
1793          * @return string The URL
1794          * @deprecated since 1.19
1795          */
1796         public function escapeFullURL( $query = '', $query2 = false ) {
1797                 wfDeprecated( __METHOD__, '1.19' );
1798                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1799         }
1800
1801         /**
1802          * Get the URL form for an internal link.
1803          * - Used in various Squid-related code, in case we have a different
1804          * internal hostname for the server from the exposed one.
1805          *
1806          * This uses $wgInternalServer to qualify the path, or $wgServer
1807          * if $wgInternalServer is not set. If the server variable used is
1808          * protocol-relative, the URL will be expanded to http://
1809          *
1810          * @see self::getLocalURL for the arguments.
1811          * @return string The URL
1812          */
1813         public function getInternalURL( $query = '', $query2 = false ) {
1814                 global $wgInternalServer, $wgServer;
1815                 $query = self::fixUrlQueryArgs( $query, $query2 );
1816                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1817                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1818                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1819                 return $url;
1820         }
1821
1822         /**
1823          * Get the URL for a canonical link, for use in things like IRC and
1824          * e-mail notifications. Uses $wgCanonicalServer and the
1825          * GetCanonicalURL hook.
1826          *
1827          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1828          *
1829          * @see self::getLocalURL for the arguments.
1830          * @return string The URL
1831          * @since 1.18
1832          */
1833         public function getCanonicalURL( $query = '', $query2 = false ) {
1834                 $query = self::fixUrlQueryArgs( $query, $query2 );
1835                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1836                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1837                 return $url;
1838         }
1839
1840         /**
1841          * HTML-escaped version of getCanonicalURL()
1842          *
1843          * @see self::getLocalURL for the arguments.
1844          * @since 1.18
1845          * @return string
1846          * @deprecated since 1.19
1847          */
1848         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1849                 wfDeprecated( __METHOD__, '1.19' );
1850                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1851         }
1852
1853         /**
1854          * Get the edit URL for this Title
1855          *
1856          * @return string The URL, or a null string if this is an interwiki link
1857          */
1858         public function getEditURL() {
1859                 if ( $this->isExternal() ) {
1860                         return '';
1861                 }
1862                 $s = $this->getLocalURL( 'action=edit' );
1863
1864                 return $s;
1865         }
1866
1867         /**
1868          * Is $wgUser watching this page?
1869          *
1870          * @deprecated since 1.20; use User::isWatched() instead.
1871          * @return bool
1872          */
1873         public function userIsWatching() {
1874                 global $wgUser;
1875
1876                 if ( is_null( $this->mWatched ) ) {
1877                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1878                                 $this->mWatched = false;
1879                         } else {
1880                                 $this->mWatched = $wgUser->isWatched( $this );
1881                         }
1882                 }
1883                 return $this->mWatched;
1884         }
1885
1886         /**
1887          * Can $wgUser read this page?
1888          *
1889          * @deprecated since 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1890          * @return bool
1891          */
1892         public function userCanRead() {
1893                 wfDeprecated( __METHOD__, '1.19' );
1894                 return $this->userCan( 'read' );
1895         }
1896
1897         /**
1898          * Can $user perform $action on this page?
1899          * This skips potentially expensive cascading permission checks
1900          * as well as avoids expensive error formatting
1901          *
1902          * Suitable for use for nonessential UI controls in common cases, but
1903          * _not_ for functional access control.
1904          *
1905          * May provide false positives, but should never provide a false negative.
1906          *
1907          * @param string $action Action that permission needs to be checked for
1908          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1909          * @return bool
1910          */
1911         public function quickUserCan( $action, $user = null ) {
1912                 return $this->userCan( $action, $user, false );
1913         }
1914
1915         /**
1916          * Can $user perform $action on this page?
1917          *
1918          * @param string $action Action that permission needs to be checked for
1919          * @param User $user User to check (since 1.19); $wgUser will be used if not
1920          *   provided.
1921          * @param bool $doExpensiveQueries Set this to false to avoid doing
1922          *   unnecessary queries.
1923          * @return bool
1924          */
1925         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1926                 if ( !$user instanceof User ) {
1927                         global $wgUser;
1928                         $user = $wgUser;
1929                 }
1930
1931                 return !count( $this->getUserPermissionsErrorsInternal(
1932                         $action, $user, $doExpensiveQueries, true ) );
1933         }
1934
1935         /**
1936          * Can $user perform $action on this page?
1937          *
1938          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1939          *
1940          * @param string $action action that permission needs to be checked for
1941          * @param User $user User to check
1942          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1943          *   queries by skipping checks for cascading protections and user blocks.
1944          * @param array $ignoreErrors of Strings Set this to a list of message keys
1945          *   whose corresponding errors may be ignored.
1946          * @return array Array of arguments to wfMessage to explain permissions problems.
1947          */
1948         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true,
1949                 $ignoreErrors = array()
1950         ) {
1951                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1952
1953                 // Remove the errors being ignored.
1954                 foreach ( $errors as $index => $error ) {
1955                         $error_key = is_array( $error ) ? $error[0] : $error;
1956
1957                         if ( in_array( $error_key, $ignoreErrors ) ) {
1958                                 unset( $errors[$index] );
1959                         }
1960                 }
1961
1962                 return $errors;
1963         }
1964
1965         /**
1966          * Permissions checks that fail most often, and which are easiest to test.
1967          *
1968          * @param string $action the action to check
1969          * @param User $user User to check
1970          * @param array $errors List of current errors
1971          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
1972          * @param bool $short Short circuit on first error
1973          *
1974          * @return array List of errors
1975          */
1976         private function checkQuickPermissions( $action, $user, $errors,
1977                 $doExpensiveQueries, $short
1978         ) {
1979                 if ( !wfRunHooks( 'TitleQuickPermissions',
1980                         array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) )
1981                 ) {
1982                         return $errors;
1983                 }
1984
1985                 if ( $action == 'create' ) {
1986                         if (
1987                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1988                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1989                         ) {
1990                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1991                         }
1992                 } elseif ( $action == 'move' ) {
1993                         if ( !$user->isAllowed( 'move-rootuserpages' )
1994                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1995                                 // Show user page-specific message only if the user can move other pages
1996                                 $errors[] = array( 'cant-move-user-page' );
1997                         }
1998
1999                         // Check if user is allowed to move files if it's a file
2000                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2001                                 $errors[] = array( 'movenotallowedfile' );
2002                         }
2003
2004                         // Check if user is allowed to move category pages if it's a category page
2005                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2006                                 $errors[] = array( 'cant-move-category-page' );
2007                         }
2008
2009                         if ( !$user->isAllowed( 'move' ) ) {
2010                                 // User can't move anything
2011                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2012                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2013                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2014                                         // custom message if logged-in users without any special rights can move
2015                                         $errors[] = array( 'movenologintext' );
2016                                 } else {
2017                                         $errors[] = array( 'movenotallowed' );
2018                                 }
2019                         }
2020                 } elseif ( $action == 'move-target' ) {
2021                         if ( !$user->isAllowed( 'move' ) ) {
2022                                 // User can't move anything
2023                                 $errors[] = array( 'movenotallowed' );
2024                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2025                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2026                                 // Show user page-specific message only if the user can move other pages
2027                                 $errors[] = array( 'cant-move-to-user-page' );
2028                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2029                                         && $this->mNamespace == NS_CATEGORY ) {
2030                                 // Show category page-specific message only if the user can move other pages
2031                                 $errors[] = array( 'cant-move-to-category-page' );
2032                         }
2033                 } elseif ( !$user->isAllowed( $action ) ) {
2034                         $errors[] = $this->missingPermissionError( $action, $short );
2035                 }
2036
2037                 return $errors;
2038         }
2039
2040         /**
2041          * Add the resulting error code to the errors array
2042          *
2043          * @param array $errors List of current errors
2044          * @param array $result Result of errors
2045          *
2046          * @return array List of errors
2047          */
2048         private function resultToError( $errors, $result ) {
2049                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2050                         // A single array representing an error
2051                         $errors[] = $result;
2052                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2053                         // A nested array representing multiple errors
2054                         $errors = array_merge( $errors, $result );
2055                 } elseif ( $result !== '' && is_string( $result ) ) {
2056                         // A string representing a message-id
2057                         $errors[] = array( $result );
2058                 } elseif ( $result === false ) {
2059                         // a generic "We don't want them to do that"
2060                         $errors[] = array( 'badaccess-group0' );
2061                 }
2062                 return $errors;
2063         }
2064
2065         /**
2066          * Check various permission hooks
2067          *
2068          * @param string $action The action to check
2069          * @param User $user User to check
2070          * @param array $errors List of current errors
2071          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2072          * @param bool $short Short circuit on first error
2073          *
2074          * @return array List of errors
2075          */
2076         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
2077                 // Use getUserPermissionsErrors instead
2078                 $result = '';
2079                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2080                         return $result ? array() : array( array( 'badaccess-group0' ) );
2081                 }
2082                 // Check getUserPermissionsErrors hook
2083                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2084                         $errors = $this->resultToError( $errors, $result );
2085                 }
2086                 // Check getUserPermissionsErrorsExpensive hook
2087                 if (
2088                         $doExpensiveQueries
2089                         && !( $short && count( $errors ) > 0 )
2090                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2091                 ) {
2092                         $errors = $this->resultToError( $errors, $result );
2093                 }
2094
2095                 return $errors;
2096         }
2097
2098         /**
2099          * Check permissions on special pages & namespaces
2100          *
2101          * @param string $action The action to check
2102          * @param User $user User to check
2103          * @param array $errors List of current errors
2104          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2105          * @param bool $short Short circuit on first error
2106          *
2107          * @return array List of errors
2108          */
2109         private function checkSpecialsAndNSPermissions( $action, $user, $errors,
2110                 $doExpensiveQueries, $short
2111         ) {
2112                 # Only 'createaccount' can be performed on special pages,
2113                 # which don't actually exist in the DB.
2114                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2115                         $errors[] = array( 'ns-specialprotected' );
2116                 }
2117
2118                 # Check $wgNamespaceProtection for restricted namespaces
2119                 if ( $this->isNamespaceProtected( $user ) ) {
2120                         $ns = $this->mNamespace == NS_MAIN ?
2121                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2122                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2123                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
2124                 }
2125
2126                 return $errors;
2127         }
2128
2129         /**
2130          * Check CSS/JS sub-page permissions
2131          *
2132          * @param string $action The action to check
2133          * @param User $user User to check
2134          * @param array $errors List of current errors
2135          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2136          * @param bool $short Short circuit on first error
2137          *
2138          * @return array List of errors
2139          */
2140         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2141                 # Protect css/js subpages of user pages
2142                 # XXX: this might be better using restrictions
2143                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2144                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2145                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2146                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2147                                         $errors[] = array( 'mycustomcssprotected' );
2148                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2149                                         $errors[] = array( 'mycustomjsprotected' );
2150                                 }
2151                         } else {
2152                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2153                                         $errors[] = array( 'customcssprotected' );
2154                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2155                                         $errors[] = array( 'customjsprotected' );
2156                                 }
2157                         }
2158                 }
2159
2160                 return $errors;
2161         }
2162
2163         /**
2164          * Check against page_restrictions table requirements on this
2165          * page. The user must possess all required rights for this
2166          * action.
2167          *
2168          * @param string $action The action to check
2169          * @param User $user User to check
2170          * @param array $errors List of current errors
2171          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2172          * @param bool $short Short circuit on first error
2173          *
2174          * @return array List of errors
2175          */
2176         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2177                 foreach ( $this->getRestrictions( $action ) as $right ) {
2178                         // Backwards compatibility, rewrite sysop -> editprotected
2179                         if ( $right == 'sysop' ) {
2180                                 $right = 'editprotected';
2181                         }
2182                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2183                         if ( $right == 'autoconfirmed' ) {
2184                                 $right = 'editsemiprotected';
2185                         }
2186                         if ( $right == '' ) {
2187                                 continue;
2188                         }
2189                         if ( !$user->isAllowed( $right ) ) {
2190                                 $errors[] = array( 'protectedpagetext', $right );
2191                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2192                                 $errors[] = array( 'protectedpagetext', 'protect' );
2193                         }
2194                 }
2195
2196                 return $errors;
2197         }
2198
2199         /**
2200          * Check restrictions on cascading pages.
2201          *
2202          * @param string $action The action to check
2203          * @param User $user User to check
2204          * @param array $errors List of current errors
2205          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2206          * @param bool $short Short circuit on first error
2207          *
2208          * @return array List of errors
2209          */
2210         private function checkCascadingSourcesRestrictions( $action, $user, $errors,
2211                 $doExpensiveQueries, $short
2212         ) {
2213                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2214                         # We /could/ use the protection level on the source page, but it's
2215                         # fairly ugly as we have to establish a precedence hierarchy for pages
2216                         # included by multiple cascade-protected pages. So just restrict
2217                         # it to people with 'protect' permission, as they could remove the
2218                         # protection anyway.
2219                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2220                         # Cascading protection depends on more than this page...
2221                         # Several cascading protected pages may include this page...
2222                         # Check each cascading level
2223                         # This is only for protection restrictions, not for all actions
2224                         if ( isset( $restrictions[$action] ) ) {
2225                                 foreach ( $restrictions[$action] as $right ) {
2226                                         // Backwards compatibility, rewrite sysop -> editprotected
2227                                         if ( $right == 'sysop' ) {
2228                                                 $right = 'editprotected';
2229                                         }
2230                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2231                                         if ( $right == 'autoconfirmed' ) {
2232                                                 $right = 'editsemiprotected';
2233                                         }
2234                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2235                                                 $pages = '';
2236                                                 foreach ( $cascadingSources as $page ) {
2237                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2238                                                 }
2239                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2240                                         }
2241                                 }
2242                         }
2243                 }
2244
2245                 return $errors;
2246         }
2247
2248         /**
2249          * Check action permissions not already checked in checkQuickPermissions
2250          *
2251          * @param string $action The action to check
2252          * @param User $user User to check
2253          * @param array $errors List of current errors
2254          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2255          * @param bool $short Short circuit on first error
2256          *
2257          * @return array List of errors
2258          */
2259         private function checkActionPermissions( $action, $user, $errors,
2260                 $doExpensiveQueries, $short
2261         ) {
2262                 global $wgDeleteRevisionsLimit, $wgLang;
2263
2264                 if ( $action == 'protect' ) {
2265                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit',
2266                                 $user, $doExpensiveQueries, true ) )
2267                         ) {
2268                                 // If they can't edit, they shouldn't protect.
2269                                 $errors[] = array( 'protect-cantedit' );
2270                         }
2271                 } elseif ( $action == 'create' ) {
2272                         $title_protection = $this->getTitleProtection();
2273                         if ( $title_protection ) {
2274                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2275                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2276                                 }
2277                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2278                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2279                                 }
2280                                 if ( $title_protection['pt_create_perm'] == ''
2281                                         || !$user->isAllowed( $title_protection['pt_create_perm'] )
2282                                 ) {
2283                                         $errors[] = array(
2284                                                 'titleprotected',
2285                                                 User::whoIs( $title_protection['pt_user'] ),
2286                                                 $title_protection['pt_reason']
2287                                         );
2288                                 }
2289                         }
2290                 } elseif ( $action == 'move' ) {
2291                         // Check for immobile pages
2292                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2293                                 // Specific message for this case
2294                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2295                         } elseif ( !$this->isMovable() ) {
2296                                 // Less specific message for rarer cases
2297                                 $errors[] = array( 'immobile-source-page' );
2298                         }
2299                 } elseif ( $action == 'move-target' ) {
2300                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2301                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2302                         } elseif ( !$this->isMovable() ) {
2303                                 $errors[] = array( 'immobile-target-page' );
2304                         }
2305                 } elseif ( $action == 'delete' ) {
2306                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2307                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2308                         ) {
2309                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2310                         }
2311                 }
2312                 return $errors;
2313         }
2314
2315         /**
2316          * Check that the user isn't blocked from editing.
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 checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2327                 // Account creation blocks handled at userlogin.
2328                 // Unblocking handled in SpecialUnblock
2329                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2330                         return $errors;
2331                 }
2332
2333                 global $wgEmailConfirmToEdit;
2334
2335                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2336                         $errors[] = array( 'confirmedittext' );
2337                 }
2338
2339                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2340                         // Don't block the user from editing their own talk page unless they've been
2341                         // explicitly blocked from that too.
2342                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2343                         // @todo FIXME: Pass the relevant context into this function.
2344                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2345                 }
2346
2347                 return $errors;
2348         }
2349
2350         /**
2351          * Check that the user is allowed to read this page.
2352          *
2353          * @param string $action The action to check
2354          * @param User $user User to check
2355          * @param array $errors List of current errors
2356          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2357          * @param bool $short Short circuit on first error
2358          *
2359          * @return array List of errors
2360          */
2361         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2362                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2363
2364                 $whitelisted = false;
2365                 if ( User::isEveryoneAllowed( 'read' ) ) {
2366                         # Shortcut for public wikis, allows skipping quite a bit of code
2367                         $whitelisted = true;
2368                 } elseif ( $user->isAllowed( 'read' ) ) {
2369                         # If the user is allowed to read pages, he is allowed to read all pages
2370                         $whitelisted = true;
2371                 } elseif ( $this->isSpecial( 'Userlogin' )
2372                         || $this->isSpecial( 'ChangePassword' )
2373                         || $this->isSpecial( 'PasswordReset' )
2374                 ) {
2375                         # Always grant access to the login page.
2376                         # Even anons need to be able to log in.
2377                         $whitelisted = true;
2378                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2379                         # Time to check the whitelist
2380                         # Only do these checks is there's something to check against
2381                         $name = $this->getPrefixedText();
2382                         $dbName = $this->getPrefixedDBkey();
2383
2384                         // Check for explicit whitelisting with and without underscores
2385                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2386                                 $whitelisted = true;
2387                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2388                                 # Old settings might have the title prefixed with
2389                                 # a colon for main-namespace pages
2390                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2391                                         $whitelisted = true;
2392                                 }
2393                         } elseif ( $this->isSpecialPage() ) {
2394                                 # If it's a special page, ditch the subpage bit and check again
2395                                 $name = $this->getDBkey();
2396                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2397                                 if ( $name ) {
2398                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2399                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2400                                                 $whitelisted = true;
2401                                         }
2402                                 }
2403                         }
2404                 }
2405
2406                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2407                         $name = $this->getPrefixedText();
2408                         // Check for regex whitelisting
2409                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2410                                 if ( preg_match( $listItem, $name ) ) {
2411                                         $whitelisted = true;
2412                                         break;
2413                                 }
2414                         }
2415                 }
2416
2417                 if ( !$whitelisted ) {
2418                         # If the title is not whitelisted, give extensions a chance to do so...
2419                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2420                         if ( !$whitelisted ) {
2421                                 $errors[] = $this->missingPermissionError( $action, $short );
2422                         }
2423                 }
2424
2425                 return $errors;
2426         }
2427
2428         /**
2429          * Get a description array when the user doesn't have the right to perform
2430          * $action (i.e. when User::isAllowed() returns false)
2431          *
2432          * @param string $action The action to check
2433          * @param bool $short Short circuit on first error
2434          * @return array List of errors
2435          */
2436         private function missingPermissionError( $action, $short ) {
2437                 // We avoid expensive display logic for quickUserCan's and such
2438                 if ( $short ) {
2439                         return array( 'badaccess-group0' );
2440                 }
2441
2442                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2443                         User::getGroupsWithPermission( $action ) );
2444
2445                 if ( count( $groups ) ) {
2446                         global $wgLang;
2447                         return array(
2448                                 'badaccess-groups',
2449                                 $wgLang->commaList( $groups ),
2450                                 count( $groups )
2451                         );
2452                 } else {
2453                         return array( 'badaccess-group0' );
2454                 }
2455         }
2456
2457         /**
2458          * Can $user perform $action on this page? This is an internal function,
2459          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2460          * checks on wfReadOnly() and blocks)
2461          *
2462          * @param string $action Action that permission needs to be checked for
2463          * @param User $user User to check
2464          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2465          * @param bool $short Set this to true to stop after the first permission error.
2466          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2467          */
2468         protected function getUserPermissionsErrorsInternal( $action, $user,
2469                 $doExpensiveQueries = true, $short = false
2470         ) {
2471                 wfProfileIn( __METHOD__ );
2472
2473                 # Read has special handling
2474                 if ( $action == 'read' ) {
2475                         $checks = array(
2476                                 'checkPermissionHooks',
2477                                 'checkReadPermissions',
2478                         );
2479                 } else {
2480                         $checks = array(
2481                                 'checkQuickPermissions',
2482                                 'checkPermissionHooks',
2483                                 'checkSpecialsAndNSPermissions',
2484                                 'checkCSSandJSPermissions',
2485                                 'checkPageRestrictions',
2486                                 'checkCascadingSourcesRestrictions',
2487                                 'checkActionPermissions',
2488                                 'checkUserBlock'
2489                         );
2490                 }
2491
2492                 $errors = array();
2493                 while ( count( $checks ) > 0 &&
2494                                 !( $short && count( $errors ) > 0 ) ) {
2495                         $method = array_shift( $checks );
2496                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2497                 }
2498
2499                 wfProfileOut( __METHOD__ );
2500                 return $errors;
2501         }
2502
2503         /**
2504          * Get a filtered list of all restriction types supported by this wiki.
2505          * @param bool $exists True to get all restriction types that apply to
2506          * titles that do exist, False for all restriction types that apply to
2507          * titles that do not exist
2508          * @return array
2509          */
2510         public static function getFilteredRestrictionTypes( $exists = true ) {
2511                 global $wgRestrictionTypes;
2512                 $types = $wgRestrictionTypes;
2513                 if ( $exists ) {
2514                         # Remove the create restriction for existing titles
2515                         $types = array_diff( $types, array( 'create' ) );
2516                 } else {
2517                         # Only the create and upload restrictions apply to non-existing titles
2518                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2519                 }
2520                 return $types;
2521         }
2522
2523         /**
2524          * Returns restriction types for the current Title
2525          *
2526          * @return array Applicable restriction types
2527          */
2528         public function getRestrictionTypes() {
2529                 if ( $this->isSpecialPage() ) {
2530                         return array();
2531                 }
2532
2533                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2534
2535                 if ( $this->getNamespace() != NS_FILE ) {
2536                         # Remove the upload restriction for non-file titles
2537                         $types = array_diff( $types, array( 'upload' ) );
2538                 }
2539
2540                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2541
2542                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2543                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2544
2545                 return $types;
2546         }
2547
2548         /**
2549          * Is this title subject to title protection?
2550          * Title protection is the one applied against creation of such title.
2551          *
2552          * @return array|bool An associative array representing any existent title
2553          *   protection, or false if there's none.
2554          */
2555         private function getTitleProtection() {
2556                 // Can't protect pages in special namespaces
2557                 if ( $this->getNamespace() < 0 ) {
2558                         return false;
2559                 }
2560
2561                 // Can't protect pages that exist.
2562                 if ( $this->exists() ) {
2563                         return false;
2564                 }
2565
2566                 if ( !isset( $this->mTitleProtection ) ) {
2567                         $dbr = wfGetDB( DB_SLAVE );
2568                         $res = $dbr->select(
2569                                 'protected_titles',
2570                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2571                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2572                                 __METHOD__
2573                         );
2574
2575                         // fetchRow returns false if there are no rows.
2576                         $this->mTitleProtection = $dbr->fetchRow( $res );
2577                 }
2578                 return $this->mTitleProtection;
2579         }
2580
2581         /**
2582          * Update the title protection status
2583          *
2584          * @deprecated since 1.19; use WikiPage::doUpdateRestrictions() instead.
2585          * @param string $create_perm Permission required for creation
2586          * @param string $reason Reason for protection
2587          * @param string $expiry Expiry timestamp
2588          * @return bool
2589          */
2590         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2591                 wfDeprecated( __METHOD__, '1.19' );
2592
2593                 global $wgUser;
2594
2595                 $limit = array( 'create' => $create_perm );
2596                 $expiry = array( 'create' => $expiry );
2597
2598                 $page = WikiPage::factory( $this );
2599                 $cascade = false;
2600                 $status = $page->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $wgUser );
2601
2602                 return $status->isOK();
2603         }
2604
2605         /**
2606          * Remove any title protection due to page existing
2607          */
2608         public function deleteTitleProtection() {
2609                 $dbw = wfGetDB( DB_MASTER );
2610
2611                 $dbw->delete(
2612                         'protected_titles',
2613                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2614                         __METHOD__
2615                 );
2616                 $this->mTitleProtection = false;
2617         }
2618
2619         /**
2620          * Is this page "semi-protected" - the *only* protection levels are listed
2621          * in $wgSemiprotectedRestrictionLevels?
2622          *
2623          * @param string $action Action to check (default: edit)
2624          * @return bool
2625          */
2626         public function isSemiProtected( $action = 'edit' ) {
2627                 global $wgSemiprotectedRestrictionLevels;
2628
2629                 $restrictions = $this->getRestrictions( $action );
2630                 $semi = $wgSemiprotectedRestrictionLevels;
2631                 if ( !$restrictions || !$semi ) {
2632                         // Not protected, or all protection is full protection
2633                         return false;
2634                 }
2635
2636                 // Remap autoconfirmed to editsemiprotected for BC
2637                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2638                         $semi[$key] = 'editsemiprotected';
2639                 }
2640                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2641                         $restrictions[$key] = 'editsemiprotected';
2642                 }
2643
2644                 return !array_diff( $restrictions, $semi );
2645         }
2646
2647         /**
2648          * Does the title correspond to a protected article?
2649          *
2650          * @param string $action the action the page is protected from,
2651          * by default checks all actions.
2652          * @return bool
2653          */
2654         public function isProtected( $action = '' ) {
2655                 global $wgRestrictionLevels;
2656
2657                 $restrictionTypes = $this->getRestrictionTypes();
2658
2659                 # Special pages have inherent protection
2660                 if ( $this->isSpecialPage() ) {
2661                         return true;
2662                 }
2663
2664                 # Check regular protection levels
2665                 foreach ( $restrictionTypes as $type ) {
2666                         if ( $action == $type || $action == '' ) {
2667                                 $r = $this->getRestrictions( $type );
2668                                 foreach ( $wgRestrictionLevels as $level ) {
2669                                         if ( in_array( $level, $r ) && $level != '' ) {
2670                                                 return true;
2671                                         }
2672                                 }
2673                         }
2674                 }
2675
2676                 return false;
2677         }
2678
2679         /**
2680          * Determines if $user is unable to edit this page because it has been protected
2681          * by $wgNamespaceProtection.
2682          *
2683          * @param User $user User object to check permissions
2684          * @return bool
2685          */
2686         public function isNamespaceProtected( User $user ) {
2687                 global $wgNamespaceProtection;
2688
2689                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2690                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2691                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2692                                         return true;
2693                                 }
2694                         }
2695                 }
2696                 return false;
2697         }
2698
2699         /**
2700          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2701          *
2702          * @return bool If the page is subject to cascading restrictions.
2703          */
2704         public function isCascadeProtected() {
2705                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2706                 return ( $sources > 0 );
2707         }
2708
2709         /**
2710          * Determines whether cascading protection sources have already been loaded from
2711          * the database.
2712          *
2713          * @param bool $getPages True to check if the pages are loaded, or false to check
2714          * if the status is loaded.
2715          * @return bool Whether or not the specified information has been loaded
2716          * @since 1.23
2717          */
2718         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2719                 return $getPages ? isset( $this->mCascadeSources ) : isset( $this->mHasCascadingRestrictions );
2720         }
2721
2722         /**
2723          * Cascading protection: Get the source of any cascading restrictions on this page.
2724          *
2725          * @param bool $getPages Whether or not to retrieve the actual pages
2726          *        that the restrictions have come from.
2727          * @return array|bool Array of Title objects of the pages from which cascading restrictions
2728          *     have come, false for none, or true if such restrictions exist, but $getPages
2729          *     was not set.  The restriction array is an array of each type, each of which
2730          *     contains a array of unique groups.
2731          */
2732         public function getCascadeProtectionSources( $getPages = true ) {
2733                 global $wgContLang;
2734                 $pagerestrictions = array();
2735
2736                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2737                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2738                 } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2739                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2740                 }
2741
2742                 wfProfileIn( __METHOD__ );
2743
2744                 $dbr = wfGetDB( DB_SLAVE );
2745
2746                 if ( $this->getNamespace() == NS_FILE ) {
2747                         $tables = array( 'imagelinks', 'page_restrictions' );
2748                         $where_clauses = array(
2749                                 'il_to' => $this->getDBkey(),
2750                                 'il_from=pr_page',
2751                                 'pr_cascade' => 1
2752                         );
2753                 } else {
2754                         $tables = array( 'templatelinks', 'page_restrictions' );
2755                         $where_clauses = array(
2756                                 'tl_namespace' => $this->getNamespace(),
2757                                 'tl_title' => $this->getDBkey(),
2758                                 'tl_from=pr_page',
2759                                 'pr_cascade' => 1
2760                         );
2761                 }
2762
2763                 if ( $getPages ) {
2764                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2765                                 'pr_expiry', 'pr_type', 'pr_level' );
2766                         $where_clauses[] = 'page_id=pr_page';
2767                         $tables[] = 'page';
2768                 } else {
2769                         $cols = array( 'pr_expiry' );
2770                 }
2771
2772                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2773
2774                 $sources = $getPages ? array() : false;
2775                 $now = wfTimestampNow();
2776                 $purgeExpired = false;
2777
2778                 foreach ( $res as $row ) {
2779                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2780                         if ( $expiry > $now ) {
2781                                 if ( $getPages ) {
2782                                         $page_id = $row->pr_page;
2783                                         $page_ns = $row->page_namespace;
2784                                         $page_title = $row->page_title;
2785                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2786                                         # Add groups needed for each restriction type if its not already there
2787                                         # Make sure this restriction type still exists
2788
2789                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2790                                                 $pagerestrictions[$row->pr_type] = array();
2791                                         }
2792
2793                                         if (
2794                                                 isset( $pagerestrictions[$row->pr_type] )
2795                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2796                                         ) {
2797                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2798                                         }
2799                                 } else {
2800                                         $sources = true;
2801                                 }
2802                         } else {
2803                                 // Trigger lazy purge of expired restrictions from the db
2804                                 $purgeExpired = true;
2805                         }
2806                 }
2807                 if ( $purgeExpired ) {
2808                         Title::purgeExpiredRestrictions();
2809                 }
2810
2811                 if ( $getPages ) {
2812                         $this->mCascadeSources = $sources;
2813                         $this->mCascadingRestrictions = $pagerestrictions;
2814                 } else {
2815                         $this->mHasCascadingRestrictions = $sources;
2816                 }
2817
2818                 wfProfileOut( __METHOD__ );
2819                 return array( $sources, $pagerestrictions );
2820         }
2821
2822         /**
2823          * Accessor for mRestrictionsLoaded
2824          *
2825          * @return bool Whether or not the page's restrictions have already been
2826          * loaded from the database
2827          * @since 1.23
2828          */
2829         public function areRestrictionsLoaded() {
2830                 return $this->mRestrictionsLoaded;
2831         }
2832
2833         /**
2834          * Accessor/initialisation for mRestrictions
2835          *
2836          * @param string $action Action that permission needs to be checked for
2837          * @return array Array of Strings the array of groups allowed to edit this article
2838          */
2839         public function getRestrictions( $action ) {
2840                 if ( !$this->mRestrictionsLoaded ) {
2841                         $this->loadRestrictions();
2842                 }
2843                 return isset( $this->mRestrictions[$action] )
2844                                 ? $this->mRestrictions[$action]
2845                                 : array();
2846         }
2847
2848         /**
2849          * Accessor/initialisation for mRestrictions
2850          *
2851          * @return array Array of Arrays of Strings the first level indexed by
2852          * action, the second level containing the names of the groups
2853          * allowed to perform each action
2854          * @since 1.23
2855          */
2856         public function getAllRestrictions() {
2857                 if ( !$this->mRestrictionsLoaded ) {
2858                         $this->loadRestrictions();
2859                 }
2860                 return $this->mRestrictions;
2861         }
2862
2863         /**
2864          * Get the expiry time for the restriction against a given action
2865          *
2866          * @param string $action
2867          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2868          *     or not protected at all, or false if the action is not recognised.
2869          */
2870         public function getRestrictionExpiry( $action ) {
2871                 if ( !$this->mRestrictionsLoaded ) {
2872                         $this->loadRestrictions();
2873                 }
2874                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2875         }
2876
2877         /**
2878          * Returns cascading restrictions for the current article
2879          *
2880          * @return bool
2881          */
2882         function areRestrictionsCascading() {
2883                 if ( !$this->mRestrictionsLoaded ) {
2884                         $this->loadRestrictions();
2885                 }
2886
2887                 return $this->mCascadeRestriction;
2888         }
2889
2890         /**
2891          * Loads a string into mRestrictions array
2892          *
2893          * @param ResultWrapper $res Resource restrictions as an SQL result.
2894          * @param string $oldFashionedRestrictions Comma-separated list of page
2895          *        restrictions from page table (pre 1.10)
2896          */
2897         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2898                 $rows = array();
2899
2900                 foreach ( $res as $row ) {
2901                         $rows[] = $row;
2902                 }
2903
2904                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2905         }
2906
2907         /**
2908          * Compiles list of active page restrictions from both page table (pre 1.10)
2909          * and page_restrictions table for this existing page.
2910          * Public for usage by LiquidThreads.
2911          *
2912          * @param array $rows Array of db result objects
2913          * @param string $oldFashionedRestrictions Comma-separated list of page
2914          *   restrictions from page table (pre 1.10)
2915          */
2916         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2917                 global $wgContLang;
2918                 $dbr = wfGetDB( DB_SLAVE );
2919
2920                 $restrictionTypes = $this->getRestrictionTypes();
2921
2922                 foreach ( $restrictionTypes as $type ) {
2923                         $this->mRestrictions[$type] = array();
2924                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2925                 }
2926
2927                 $this->mCascadeRestriction = false;
2928
2929                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2930
2931                 if ( $oldFashionedRestrictions === null ) {
2932                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2933                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2934                 }
2935
2936                 if ( $oldFashionedRestrictions != '' ) {
2937
2938                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2939                                 $temp = explode( '=', trim( $restrict ) );
2940                                 if ( count( $temp ) == 1 ) {
2941                                         // old old format should be treated as edit/move restriction
2942                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2943                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2944                                 } else {
2945                                         $restriction = trim( $temp[1] );
2946                                         if ( $restriction != '' ) { //some old entries are empty
2947                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2948                                         }
2949                                 }
2950                         }
2951
2952                         $this->mOldRestrictions = true;
2953
2954                 }
2955
2956                 if ( count( $rows ) ) {
2957                         # Current system - load second to make them override.
2958                         $now = wfTimestampNow();
2959                         $purgeExpired = false;
2960
2961                         # Cycle through all the restrictions.
2962                         foreach ( $rows as $row ) {
2963
2964                                 // Don't take care of restrictions types that aren't allowed
2965                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2966                                         continue;
2967                                 }
2968
2969                                 // This code should be refactored, now that it's being used more generally,
2970                                 // But I don't really see any harm in leaving it in Block for now -werdna
2971                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2972
2973                                 // Only apply the restrictions if they haven't expired!
2974                                 if ( !$expiry || $expiry > $now ) {
2975                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2976                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2977
2978                                         $this->mCascadeRestriction |= $row->pr_cascade;
2979                                 } else {
2980                                         // Trigger a lazy purge of expired restrictions
2981                                         $purgeExpired = true;
2982                                 }
2983                         }
2984
2985                         if ( $purgeExpired ) {
2986                                 Title::purgeExpiredRestrictions();
2987                         }
2988                 }
2989
2990                 $this->mRestrictionsLoaded = true;
2991         }
2992
2993         /**
2994          * Load restrictions from the page_restrictions table
2995          *
2996          * @param string $oldFashionedRestrictions Comma-separated list of page
2997          *   restrictions from page table (pre 1.10)
2998          */
2999         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3000                 global $wgContLang;
3001                 if ( !$this->mRestrictionsLoaded ) {
3002                         if ( $this->exists() ) {
3003                                 $dbr = wfGetDB( DB_SLAVE );
3004
3005                                 $res = $dbr->select(
3006                                         'page_restrictions',
3007                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
3008                                         array( 'pr_page' => $this->getArticleID() ),
3009                                         __METHOD__
3010                                 );
3011
3012                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
3013                         } else {
3014                                 $title_protection = $this->getTitleProtection();
3015
3016                                 if ( $title_protection ) {
3017                                         $now = wfTimestampNow();
3018                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
3019
3020                                         if ( !$expiry || $expiry > $now ) {
3021                                                 // Apply the restrictions
3022                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3023                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
3024                                         } else { // Get rid of the old restrictions
3025                                                 Title::purgeExpiredRestrictions();
3026                                                 $this->mTitleProtection = false;
3027                                         }
3028                                 } else {
3029                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
3030                                 }
3031                                 $this->mRestrictionsLoaded = true;
3032                         }
3033                 }
3034         }
3035
3036         /**
3037          * Flush the protection cache in this object and force reload from the database.
3038          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3039          */
3040         public function flushRestrictions() {
3041                 $this->mRestrictionsLoaded = false;
3042                 $this->mTitleProtection = null;
3043         }
3044
3045         /**
3046          * Purge expired restrictions from the page_restrictions table
3047          */
3048         static function purgeExpiredRestrictions() {
3049                 if ( wfReadOnly() ) {
3050                         return;
3051                 }
3052
3053                 $method = __METHOD__;
3054                 $dbw = wfGetDB( DB_MASTER );
3055                 $dbw->onTransactionIdle( function() use ( $dbw, $method ) {
3056                         $dbw->delete(
3057                                 'page_restrictions',
3058                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3059                                 $method
3060                         );
3061                         $dbw->delete(
3062                                 'protected_titles',
3063                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3064                                 $method
3065                         );
3066                 } );
3067         }
3068
3069         /**
3070          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3071          *
3072          * @return bool
3073          */
3074         public function hasSubpages() {
3075                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3076                         # Duh
3077                         return false;
3078                 }
3079
3080                 # We dynamically add a member variable for the purpose of this method
3081                 # alone to cache the result.  There's no point in having it hanging
3082                 # around uninitialized in every Title object; therefore we only add it
3083                 # if needed and don't declare it statically.
3084                 if ( !isset( $this->mHasSubpages ) ) {
3085                         $this->mHasSubpages = false;
3086                         $subpages = $this->getSubpages( 1 );
3087                         if ( $subpages instanceof TitleArray ) {
3088                                 $this->mHasSubpages = (bool)$subpages->count();
3089                         }
3090                 }
3091
3092                 return $this->mHasSubpages;
3093         }
3094
3095         /**
3096          * Get all subpages of this page.
3097          *
3098          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3099          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3100          *  doesn't allow subpages
3101          */
3102         public function getSubpages( $limit = -1 ) {
3103                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3104                         return array();
3105                 }
3106
3107                 $dbr = wfGetDB( DB_SLAVE );
3108                 $conds['page_namespace'] = $this->getNamespace();
3109                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3110                 $options = array();
3111                 if ( $limit > -1 ) {
3112                         $options['LIMIT'] = $limit;
3113                 }
3114                 $this->mSubpages = TitleArray::newFromResult(
3115                         $dbr->select( 'page',
3116                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3117                                 $conds,
3118                                 __METHOD__,
3119                                 $options
3120                         )
3121                 );
3122                 return $this->mSubpages;
3123         }
3124
3125         /**
3126          * Is there a version of this page in the deletion archive?
3127          *
3128          * @return int The number of archived revisions
3129          */
3130         public function isDeleted() {
3131                 if ( $this->getNamespace() < 0 ) {
3132                         $n = 0;
3133                 } else {
3134                         $dbr = wfGetDB( DB_SLAVE );
3135
3136                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3137                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3138                                 __METHOD__
3139                         );
3140                         if ( $this->getNamespace() == NS_FILE ) {
3141                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3142                                         array( 'fa_name' => $this->getDBkey() ),
3143                                         __METHOD__
3144                                 );
3145                         }
3146                 }
3147                 return (int)$n;
3148         }
3149
3150         /**
3151          * Is there a version of this page in the deletion archive?
3152          *
3153          * @return bool
3154          */
3155         public function isDeletedQuick() {
3156                 if ( $this->getNamespace() < 0 ) {
3157                         return false;
3158                 }
3159                 $dbr = wfGetDB( DB_SLAVE );
3160                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3161                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3162                         __METHOD__
3163                 );
3164                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3165                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3166                                 array( 'fa_name' => $this->getDBkey() ),
3167                                 __METHOD__
3168                         );
3169                 }
3170                 return $deleted;
3171         }
3172
3173         /**
3174          * Get the article ID for this Title from the link cache,
3175          * adding it if necessary
3176          *
3177          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3178          *  for update
3179          * @return int The ID
3180          */
3181         public function getArticleID( $flags = 0 ) {
3182                 if ( $this->getNamespace() < 0 ) {
3183                         $this->mArticleID = 0;
3184                         return $this->mArticleID;
3185                 }
3186                 $linkCache = LinkCache::singleton();
3187                 if ( $flags & self::GAID_FOR_UPDATE ) {
3188                         $oldUpdate = $linkCache->forUpdate( true );
3189                         $linkCache->clearLink( $this );
3190                         $this->mArticleID = $linkCache->addLinkObj( $this );
3191                         $linkCache->forUpdate( $oldUpdate );
3192                 } else {
3193                         if ( -1 == $this->mArticleID ) {
3194                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3195                         }
3196                 }
3197                 return $this->mArticleID;
3198         }
3199
3200         /**
3201          * Is this an article that is a redirect page?
3202          * Uses link cache, adding it if necessary
3203          *
3204          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3205          * @return bool
3206          */
3207         public function isRedirect( $flags = 0 ) {
3208                 if ( !is_null( $this->mRedirect ) ) {
3209                         return $this->mRedirect;
3210                 }
3211                 # Calling getArticleID() loads the field from cache as needed
3212                 if ( !$this->getArticleID( $flags ) ) {
3213                         $this->mRedirect = false;
3214                         return $this->mRedirect;
3215                 }
3216
3217                 $linkCache = LinkCache::singleton();
3218                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3219                 if ( $cached === null ) {
3220                         # Trust LinkCache's state over our own
3221                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3222                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3223                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3224                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3225                         # LinkCache to refresh its data from the master.
3226                         $this->mRedirect = false;
3227                         return $this->mRedirect;
3228                 }
3229
3230                 $this->mRedirect = (bool)$cached;
3231
3232                 return $this->mRedirect;
3233         }
3234
3235         /**
3236          * What is the length of this page?
3237          * Uses link cache, adding it if necessary
3238          *
3239          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3240          * @return int
3241          */
3242         public function getLength( $flags = 0 ) {
3243                 if ( $this->mLength != -1 ) {
3244                         return $this->mLength;
3245                 }
3246                 # Calling getArticleID() loads the field from cache as needed
3247                 if ( !$this->getArticleID( $flags ) ) {
3248                         $this->mLength = 0;
3249                         return $this->mLength;
3250                 }
3251                 $linkCache = LinkCache::singleton();
3252                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3253                 if ( $cached === null ) {
3254                         # Trust LinkCache's state over our own, as for isRedirect()
3255                         $this->mLength = 0;
3256                         return $this->mLength;
3257                 }
3258
3259                 $this->mLength = intval( $cached );
3260
3261                 return $this->mLength;
3262         }
3263
3264         /**
3265          * What is the page_latest field for this page?
3266          *
3267          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3268          * @return int Int or 0 if the page doesn't exist
3269          */
3270         public function getLatestRevID( $flags = 0 ) {
3271                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3272                         return intval( $this->mLatestID );
3273                 }
3274                 # Calling getArticleID() loads the field from cache as needed
3275                 if ( !$this->getArticleID( $flags ) ) {
3276                         $this->mLatestID = 0;
3277                         return $this->mLatestID;
3278                 }
3279                 $linkCache = LinkCache::singleton();
3280                 $linkCache->addLinkObj( $this );
3281                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3282                 if ( $cached === null ) {
3283                         # Trust LinkCache's state over our own, as for isRedirect()
3284                         $this->mLatestID = 0;
3285                         return $this->mLatestID;
3286                 }
3287
3288                 $this->mLatestID = intval( $cached );
3289
3290                 return $this->mLatestID;
3291         }
3292
3293         /**
3294          * This clears some fields in this object, and clears any associated
3295          * keys in the "bad links" section of the link cache.
3296          *
3297          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3298          * loading of the new page_id. It's also called from
3299          * WikiPage::doDeleteArticleReal()
3300          *
3301          * @param int $newid The new Article ID
3302          */
3303         public function resetArticleID( $newid ) {
3304                 $linkCache = LinkCache::singleton();
3305                 $linkCache->clearLink( $this );
3306
3307                 if ( $newid === false ) {
3308                         $this->mArticleID = -1;
3309                 } else {
3310                         $this->mArticleID = intval( $newid );
3311                 }
3312                 $this->mRestrictionsLoaded = false;
3313                 $this->mRestrictions = array();
3314                 $this->mRedirect = null;
3315                 $this->mLength = -1;
3316                 $this->mLatestID = false;
3317                 $this->mContentModel = false;
3318                 $this->mEstimateRevisions = null;
3319                 $this->mPageLanguage = false;
3320         }
3321
3322         /**
3323          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3324          *
3325          * @param string $text Containing title to capitalize
3326          * @param int $ns Namespace index, defaults to NS_MAIN
3327          * @return string Containing capitalized title
3328          */
3329         public static function capitalize( $text, $ns = NS_MAIN ) {
3330                 global $wgContLang;
3331
3332                 if ( MWNamespace::isCapitalized( $ns ) ) {
3333                         return $wgContLang->ucfirst( $text );
3334                 } else {
3335                         return $text;
3336                 }
3337         }
3338
3339         /**
3340          * Secure and split - main initialisation function for this object
3341          *
3342          * Assumes that mDbkeyform has been set, and is urldecoded
3343          * and uses underscores, but not otherwise munged.  This function
3344          * removes illegal characters, splits off the interwiki and
3345          * namespace prefixes, sets the other forms, and canonicalizes
3346          * everything.
3347          *
3348          * @return bool True on success
3349          */
3350         private function secureAndSplit() {
3351                 # Initialisation
3352                 $this->mInterwiki = '';
3353                 $this->mFragment = '';
3354                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3355
3356                 $dbkey = $this->mDbkeyform;
3357
3358                 try {
3359                         // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3360                         //        the parsing code with Title, while avoiding massive refactoring.
3361                         // @todo: get rid of secureAndSplit, refactor parsing code.
3362                         $parser = $this->getTitleParser();
3363                         $parts = $parser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3364                 } catch ( MalformedTitleException $ex ) {
3365                         return false;
3366                 }
3367
3368                 # Fill fields
3369                 $this->setFragment( '#' . $parts['fragment'] );
3370                 $this->mInterwiki = $parts['interwiki'];
3371                 $this->mNamespace = $parts['namespace'];
3372                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3373
3374                 $this->mDbkeyform = $parts['dbkey'];
3375                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3376                 $this->mTextform = str_replace( '_', ' ', $this->mDbkeyform );
3377
3378                 # We already know that some pages won't be in the database!
3379                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3380                         $this->mArticleID = 0;
3381                 }
3382
3383                 return true;
3384         }
3385
3386         /**
3387          * Get an array of Title objects linking to this Title
3388          * Also stores the IDs in the link cache.
3389          *
3390          * WARNING: do not use this function on arbitrary user-supplied titles!
3391          * On heavily-used templates it will max out the memory.
3392          *
3393          * @param array $options May be FOR UPDATE
3394          * @param string $table Table name
3395          * @param string $prefix Fields prefix
3396          * @return Title[] Array of Title objects linking here
3397          */
3398         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3399                 if ( count( $options ) > 0 ) {
3400                         $db = wfGetDB( DB_MASTER );
3401                 } else {
3402                         $db = wfGetDB( DB_SLAVE );
3403                 }
3404
3405                 $res = $db->select(
3406                         array( 'page', $table ),
3407                         self::getSelectFields(),
3408                         array(
3409                                 "{$prefix}_from=page_id",
3410                                 "{$prefix}_namespace" => $this->getNamespace(),
3411                                 "{$prefix}_title" => $this->getDBkey() ),
3412                         __METHOD__,
3413                         $options
3414                 );
3415
3416                 $retVal = array();
3417                 if ( $res->numRows() ) {
3418                         $linkCache = LinkCache::singleton();
3419                         foreach ( $res as $row ) {
3420                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3421                                 if ( $titleObj ) {
3422                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3423                                         $retVal[] = $titleObj;
3424                                 }
3425                         }
3426                 }
3427                 return $retVal;
3428         }
3429
3430         /**
3431          * Get an array of Title objects using this Title as a template
3432          * Also stores the IDs in the link cache.
3433          *
3434          * WARNING: do not use this function on arbitrary user-supplied titles!
3435          * On heavily-used templates it will max out the memory.
3436          *
3437          * @param array $options May be FOR UPDATE
3438          * @return Title[] Array of Title the Title objects linking here
3439          */
3440         public function getTemplateLinksTo( $options = array() ) {
3441                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3442         }
3443
3444         /**
3445          * Get an array of Title objects linked from this Title
3446          * Also stores the IDs in the link cache.
3447          *
3448          * WARNING: do not use this function on arbitrary user-supplied titles!
3449          * On heavily-used templates it will max out the memory.
3450          *
3451          * @param array $options May be FOR UPDATE
3452          * @param string $table Table name
3453          * @param string $prefix Fields prefix
3454          * @return array Array of Title objects linking here
3455          */
3456         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3457                 global $wgContentHandlerUseDB;
3458
3459                 $id = $this->getArticleID();
3460
3461                 # If the page doesn't exist; there can't be any link from this page
3462                 if ( !$id ) {
3463                         return array();
3464                 }
3465
3466                 if ( count( $options ) > 0 ) {
3467                         $db = wfGetDB( DB_MASTER );
3468                 } else {
3469                         $db = wfGetDB( DB_SLAVE );
3470                 }
3471
3472                 $namespaceFiled = "{$prefix}_namespace";
3473                 $titleField = "{$prefix}_title";
3474
3475                 $fields = array(
3476                         $namespaceFiled,
3477                         $titleField,
3478                         'page_id',
3479                         'page_len',
3480                         'page_is_redirect',
3481                         'page_latest'
3482                 );
3483
3484                 if ( $wgContentHandlerUseDB ) {
3485                         $fields[] = 'page_content_model';
3486                 }
3487
3488                 $res = $db->select(
3489                         array( $table, 'page' ),
3490                         $fields,
3491                         array( "{$prefix}_from" => $id ),
3492                         __METHOD__,
3493                         $options,
3494                         array( 'page' => array(
3495                                 'LEFT JOIN',
3496                                 array( "page_namespace=$namespaceFiled", "page_title=$titleField" )
3497                         ) )
3498                 );
3499
3500                 $retVal = array();
3501                 if ( $res->numRows() ) {
3502                         $linkCache = LinkCache::singleton();
3503                         foreach ( $res as $row ) {
3504                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3505                                 if ( $titleObj ) {
3506                                         if ( $row->page_id ) {
3507                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3508                                         } else {
3509                                                 $linkCache->addBadLinkObj( $titleObj );
3510                                         }
3511                                         $retVal[] = $titleObj;
3512                                 }
3513                         }
3514                 }
3515                 return $retVal;
3516         }
3517
3518         /**
3519          * Get an array of Title objects used on this Title as a template
3520          * Also stores the IDs in the link cache.
3521          *
3522          * WARNING: do not use this function on arbitrary user-supplied titles!
3523          * On heavily-used templates it will max out the memory.
3524          *
3525          * @param array $options May be FOR UPDATE
3526          * @return Title[] Array of Title the Title objects used here
3527          */
3528         public function getTemplateLinksFrom( $options = array() ) {
3529                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3530         }
3531
3532         /**
3533          * Get an array of Title objects referring to non-existent articles linked
3534          * from this page.
3535          *
3536          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3537          *   should use redirect table in this case).
3538          * @return Title[] Array of Title the Title objects
3539          */
3540         public function getBrokenLinksFrom() {
3541                 if ( $this->getArticleID() == 0 ) {
3542                         # All links from article ID 0 are false positives
3543                         return array();
3544                 }
3545
3546                 $dbr = wfGetDB( DB_SLAVE );
3547                 $res = $dbr->select(
3548                         array( 'page', 'pagelinks' ),
3549                         array( 'pl_namespace', 'pl_title' ),
3550                         array(
3551                                 'pl_from' => $this->getArticleID(),
3552                                 'page_namespace IS NULL'
3553                         ),
3554                         __METHOD__, array(),
3555                         array(
3556                                 'page' => array(
3557                                         'LEFT JOIN',
3558                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3559                                 )
3560                         )
3561                 );
3562
3563                 $retVal = array();
3564                 foreach ( $res as $row ) {
3565                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3566                 }
3567                 return $retVal;
3568         }
3569
3570         /**
3571          * Get a list of URLs to purge from the Squid cache when this
3572          * page changes
3573          *
3574          * @return string[] Array of String the URLs
3575          */
3576         public function getSquidURLs() {
3577                 $urls = array(
3578                         $this->getInternalURL(),
3579                         $this->getInternalURL( 'action=history' )
3580                 );
3581
3582                 $pageLang = $this->getPageLanguage();
3583                 if ( $pageLang->hasVariants() ) {
3584                         $variants = $pageLang->getVariants();
3585                         foreach ( $variants as $vCode ) {
3586                                 $urls[] = $this->getInternalURL( '', $vCode );
3587                         }
3588                 }
3589
3590                 // If we are looking at a css/js user subpage, purge the action=raw.
3591                 if ( $this->isJsSubpage() ) {
3592                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3593                 } elseif ( $this->isCssSubpage() ) {
3594                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3595                 }
3596
3597                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3598                 return $urls;
3599         }
3600
3601         /**
3602          * Purge all applicable Squid URLs
3603          */
3604         public function purgeSquid() {
3605                 global $wgUseSquid;
3606                 if ( $wgUseSquid ) {
3607                         $urls = $this->getSquidURLs();
3608                         $u = new SquidUpdate( $urls );
3609                         $u->doUpdate();
3610                 }
3611         }
3612
3613         /**
3614          * Move this page without authentication
3615          *
3616          * @param Title $nt The new page Title
3617          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3618          */
3619         public function moveNoAuth( &$nt ) {
3620                 return $this->moveTo( $nt, false );
3621         }
3622
3623         /**
3624          * Check whether a given move operation would be valid.
3625          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3626          *
3627          * @param Title $nt The new title
3628          * @param bool $auth Indicates whether $wgUser's permissions
3629          *  should be checked
3630          * @param string $reason Is the log summary of the move, used for spam checking
3631          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3632          */
3633         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3634                 global $wgUser, $wgContentHandlerUseDB;
3635
3636                 $errors = array();
3637                 if ( !$nt ) {
3638                         // Normally we'd add this to $errors, but we'll get
3639                         // lots of syntax errors if $nt is not an object
3640                         return array( array( 'badtitletext' ) );
3641                 }
3642                 if ( $this->equals( $nt ) ) {
3643                         $errors[] = array( 'selfmove' );
3644                 }
3645                 if ( !$this->isMovable() ) {
3646                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3647                 }
3648                 if ( $nt->isExternal() ) {
3649                         $errors[] = array( 'immobile-target-namespace-iw' );
3650                 }
3651                 if ( !$nt->isMovable() ) {
3652                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3653                 }
3654
3655                 $oldid = $this->getArticleID();
3656                 $newid = $nt->getArticleID();
3657
3658                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3659                         $errors[] = array( 'articleexists' );
3660                 }
3661                 if (
3662                         ( $this->getDBkey() == '' ) ||
3663                         ( !$oldid ) ||
3664                         ( $nt->getDBkey() == '' )
3665                 ) {
3666                         $errors[] = array( 'badarticleerror' );
3667                 }
3668
3669                 // Content model checks
3670                 if ( !$wgContentHandlerUseDB &&
3671                                 $this->getContentModel() !== $nt->getContentModel() ) {
3672                         // can't move a page if that would change the page's content model
3673                         $errors[] = array(
3674                                 'bad-target-model',
3675                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3676                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3677                         );
3678                 }
3679
3680                 // Image-specific checks
3681                 if ( $this->getNamespace() == NS_FILE ) {
3682                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3683                 }
3684
3685                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3686                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3687                 }
3688
3689                 if ( $auth ) {
3690                         $errors = wfMergeErrorArrays( $errors,
3691                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3692                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3693                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3694                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3695                 }
3696
3697                 $match = EditPage::matchSummarySpamRegex( $reason );
3698                 if ( $match !== false ) {
3699                         // This is kind of lame, won't display nice
3700                         $errors[] = array( 'spamprotectiontext' );
3701                 }
3702
3703                 $err = null;
3704                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3705                         $errors[] = array( 'hookaborted', $err );
3706                 }
3707
3708                 # The move is allowed only if (1) the target doesn't exist, or
3709                 # (2) the target is a redirect to the source, and has no history
3710                 # (so we can undo bad moves right after they're done).
3711
3712                 if ( 0 != $newid ) { # Target exists; check for validity
3713                         if ( !$this->isValidMoveTarget( $nt ) ) {
3714                                 $errors[] = array( 'articleexists' );
3715                         }
3716                 } else {
3717                         $tp = $nt->getTitleProtection();
3718                         $right = $tp['pt_create_perm'];
3719                         if ( $right == 'sysop' ) {
3720                                 $right = 'editprotected'; // B/C
3721                         }
3722                         if ( $right == 'autoconfirmed' ) {
3723                                 $right = 'editsemiprotected'; // B/C
3724                         }
3725                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3726                                 $errors[] = array( 'cantmove-titleprotected' );
3727                         }
3728                 }
3729                 if ( empty( $errors ) ) {
3730                         return true;
3731                 }
3732                 return $errors;
3733         }
3734
3735         /**
3736          * Check if the requested move target is a valid file move target
3737          * @param Title $nt Target title
3738          * @return array List of errors
3739          */
3740         protected function validateFileMoveOperation( $nt ) {
3741                 global $wgUser;
3742
3743                 $errors = array();
3744
3745                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3746
3747                 $file = wfLocalFile( $this );
3748                 if ( $file->exists() ) {
3749                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3750                                 $errors[] = array( 'imageinvalidfilename' );
3751                         }
3752                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3753                                 $errors[] = array( 'imagetypemismatch' );
3754                         }
3755                 }
3756
3757                 if ( $nt->getNamespace() != NS_FILE ) {
3758                         $errors[] = array( 'imagenocrossnamespace' );
3759                         // From here we want to do checks on a file object, so if we can't
3760                         // create one, we must return.
3761                         return $errors;
3762                 }
3763
3764                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3765
3766                 $destFile = wfLocalFile( $nt );
3767                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3768                         $errors[] = array( 'file-exists-sharedrepo' );
3769                 }
3770
3771                 return $errors;
3772         }
3773
3774         /**
3775          * Move a title to a new location
3776          *
3777          * @param Title $nt The new title
3778          * @param bool $auth Indicates whether $wgUser's permissions
3779          *  should be checked
3780          * @param string $reason The reason for the move
3781          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3782          *  Ignored if the user doesn't have the suppressredirect right.
3783          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3784          */
3785         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3786                 global $wgUser;
3787                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3788                 if ( is_array( $err ) ) {
3789                         // Auto-block user's IP if the account was "hard" blocked
3790                         $wgUser->spreadAnyEditBlock();
3791                         return $err;
3792                 }
3793                 // Check suppressredirect permission
3794                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3795                         $createRedirect = true;
3796                 }
3797
3798                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3799
3800                 // If it is a file, move it first.
3801                 // It is done before all other moving stuff is done because it's hard to revert.
3802                 $dbw = wfGetDB( DB_MASTER );
3803                 if ( $this->getNamespace() == NS_FILE ) {
3804                         $file = wfLocalFile( $this );
3805                         if ( $file->exists() ) {
3806                                 $status = $file->move( $nt );
3807                                 if ( !$status->isOk() ) {
3808                                         return $status->getErrorsArray();
3809                                 }
3810                         }
3811                         // Clear RepoGroup process cache
3812                         RepoGroup::singleton()->clearCache( $this );
3813                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3814                 }
3815
3816                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3817                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3818                 $protected = $this->isProtected();
3819
3820                 // Do the actual move
3821                 $this->moveToInternal( $nt, $reason, $createRedirect );
3822
3823                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3824                 // cl_timestamp, which may disturb time-based lists on some sites.
3825                 $prefixes = $dbw->select(
3826                         'categorylinks',
3827                         array( 'cl_sortkey_prefix', 'cl_to' ),
3828                         array( 'cl_from' => $pageid ),
3829                         __METHOD__
3830                 );
3831                 foreach ( $prefixes as $prefixRow ) {
3832                         $prefix = $prefixRow->cl_sortkey_prefix;
3833                         $catTo = $prefixRow->cl_to;
3834                         $dbw->update( 'categorylinks',
3835                                 array(
3836                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3837                                                 $nt->getCategorySortkey( $prefix ) ),
3838                                         'cl_timestamp=cl_timestamp' ),
3839                                 array(
3840                                         'cl_from' => $pageid,
3841                                         'cl_to' => $catTo ),
3842                                 __METHOD__
3843                         );
3844                 }
3845
3846                 $redirid = $this->getArticleID();
3847
3848                 if ( $protected ) {
3849                         # Protect the redirect title as the title used to be...
3850                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3851                                 array(
3852                                         'pr_page' => $redirid,
3853                                         'pr_type' => 'pr_type',
3854                                         'pr_level' => 'pr_level',
3855                                         'pr_cascade' => 'pr_cascade',
3856                                         'pr_user' => 'pr_user',
3857                                         'pr_expiry' => 'pr_expiry'
3858                                 ),
3859                                 array( 'pr_page' => $pageid ),
3860                                 __METHOD__,
3861                                 array( 'IGNORE' )
3862                         );
3863                         # Update the protection log
3864                         $log = new LogPage( 'protect' );
3865                         $comment = wfMessage(
3866                                 'prot_1movedto2',
3867                                 $this->getPrefixedText(),
3868                                 $nt->getPrefixedText()
3869                         )->inContentLanguage()->text();
3870                         if ( $reason ) {
3871                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3872                         }
3873                         // @todo FIXME: $params?
3874                         $logId = $log->addEntry(
3875                                 'move_prot',
3876                                 $nt,
3877                                 $comment,
3878                                 array( $this->getPrefixedText() ),
3879                                 $wgUser
3880                         );
3881
3882                         // reread inserted pr_ids for log relation
3883                         $insertedPrIds = $dbw->select(
3884                                 'page_restrictions',
3885                                 'pr_id',
3886                                 array( 'pr_page' => $redirid ),
3887                                 __METHOD__
3888                         );
3889                         $logRelationsValues = array();
3890                         foreach ( $insertedPrIds as $prid ) {
3891                                 $logRelationsValues[] = $prid->pr_id;
3892                         }
3893                         $log->addRelations( 'pr_id', $logRelationsValues, $logId );
3894                 }
3895
3896                 # Update watchlists
3897                 $oldnamespace = MWNamespace::getSubject( $this->getNamespace() );
3898                 $newnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3899                 $oldtitle = $this->getDBkey();
3900                 $newtitle = $nt->getDBkey();
3901
3902                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3903                         WatchedItem::duplicateEntries( $this, $nt );
3904                 }
3905
3906                 $dbw->commit( __METHOD__ );
3907
3908                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid, $reason ) );
3909                 return true;
3910         }
3911
3912         /**
3913          * Move page to a title which is either a redirect to the
3914          * source page or nonexistent
3915          *
3916          * @param Title $nt The page to move to, which should be a redirect or nonexistent
3917          * @param string $reason The reason for the move
3918          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3919          *   if the user has the suppressredirect right
3920          * @throws MWException
3921          */
3922         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3923                 global $wgUser, $wgContLang;
3924
3925                 if ( $nt->exists() ) {
3926                         $moveOverRedirect = true;
3927                         $logType = 'move_redir';
3928                 } else {
3929                         $moveOverRedirect = false;
3930                         $logType = 'move';
3931                 }
3932
3933                 if ( $createRedirect ) {
3934                         if ( $this->getNamespace() == NS_CATEGORY
3935                                 && !wfMessage( 'category-move-redirect-override' )->isDisabled()
3936                         ) {
3937                                 $redirectContent = new WikitextContent(
3938                                         wfMessage( 'category-move-redirect-override' )
3939                                                 ->params( $nt->getPrefixedText() )->inContentLanguage()->plain() );
3940                         } else {
3941                                 $contentHandler = ContentHandler::getForTitle( $this );
3942                                 $redirectContent = $contentHandler->makeRedirectContent( $nt,
3943                                         wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3944                         }
3945
3946                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3947                 } else {
3948                         $redirectContent = null;
3949                 }
3950
3951                 $logEntry = new ManualLogEntry( 'move', $logType );
3952                 $logEntry->setPerformer( $wgUser );
3953                 $logEntry->setTarget( $this );
3954                 $logEntry->setComment( $reason );
3955                 $logEntry->setParameters( array(
3956                         '4::target' => $nt->getPrefixedText(),
3957                         '5::noredir' => $redirectContent ? '0': '1',
3958                 ) );
3959
3960                 $formatter = LogFormatter::newFromEntry( $logEntry );
3961                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3962                 $comment = $formatter->getPlainActionText();
3963                 if ( $reason ) {
3964                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3965                 }
3966                 # Truncate for whole multibyte characters.
3967                 $comment = $wgContLang->truncate( $comment, 255 );
3968
3969                 $oldid = $this->getArticleID();
3970
3971                 $dbw = wfGetDB( DB_MASTER );
3972
3973                 $newpage = WikiPage::factory( $nt );
3974
3975                 if ( $moveOverRedirect ) {
3976                         $newid = $nt->getArticleID();
3977                         $newcontent = $newpage->getContent();
3978
3979                         # Delete the old redirect. We don't save it to history since
3980                         # by definition if we've got here it's rather uninteresting.
3981                         # We have to remove it so that the next step doesn't trigger
3982                         # a conflict on the unique namespace+title index...
3983                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3984
3985                         $newpage->doDeleteUpdates( $newid, $newcontent );
3986                 }
3987
3988                 # Save a null revision in the page's history notifying of the move
3989                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true, $wgUser );
3990                 if ( !is_object( $nullRevision ) ) {
3991                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3992                 }
3993
3994                 $nullRevision->insertOn( $dbw );
3995
3996                 # Change the name of the target page:
3997                 $dbw->update( 'page',
3998                         /* SET */ array(
3999                                 'page_namespace' => $nt->getNamespace(),
4000                                 'page_title' => $nt->getDBkey(),
4001                         ),
4002                         /* WHERE */ array( 'page_id' => $oldid ),
4003                         __METHOD__
4004                 );
4005
4006                 // clean up the old title before reset article id - bug 45348
4007                 if ( !$redirectContent ) {
4008                         WikiPage::onArticleDelete( $this );
4009                 }
4010
4011                 $this->resetArticleID( 0 ); // 0 == non existing
4012                 $nt->resetArticleID( $oldid );
4013                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
4014
4015                 $newpage->updateRevisionOn( $dbw, $nullRevision );
4016
4017                 wfRunHooks( 'NewRevisionFromEditComplete',
4018                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
4019
4020                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
4021
4022                 if ( !$moveOverRedirect ) {
4023                         WikiPage::onArticleCreate( $nt );
4024                 }
4025
4026                 # Recreate the redirect, this time in the other direction.
4027                 if ( $redirectContent ) {
4028                         $redirectArticle = WikiPage::factory( $this );
4029                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
4030                         $newid = $redirectArticle->insertOn( $dbw );
4031                         if ( $newid ) { // sanity
4032                                 $this->resetArticleID( $newid );
4033                                 $redirectRevision = new Revision( array(
4034                                         'title' => $this, // for determining the default content model
4035                                         'page' => $newid,
4036                                         'user_text' => $wgUser->getName(),
4037                                         'user' => $wgUser->getId(),
4038                                         'comment' => $comment,
4039                                         'content' => $redirectContent ) );
4040                                 $redirectRevision->insertOn( $dbw );
4041                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
4042
4043                                 wfRunHooks( 'NewRevisionFromEditComplete',
4044                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
4045
4046                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
4047                         }
4048                 }
4049
4050                 # Log the move
4051                 $logid = $logEntry->insert();
4052                 $logEntry->publish( $logid );
4053         }
4054
4055         /**
4056          * Move this page's subpages to be subpages of $nt
4057          *
4058          * @param Title $nt Move target
4059          * @param bool $auth Whether $wgUser's permissions should be checked
4060          * @param string $reason The reason for the move
4061          * @param bool $createRedirect Whether to create redirects from the old subpages to
4062          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4063          * @return array Array with old page titles as keys, and strings (new page titles) or
4064          *     arrays (errors) as values, or an error array with numeric indices if no pages
4065          *     were moved
4066          */
4067         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
4068                 global $wgMaximumMovedPages;
4069                 // Check permissions
4070                 if ( !$this->userCan( 'move-subpages' ) ) {
4071                         return array( 'cant-move-subpages' );
4072                 }
4073                 // Do the source and target namespaces support subpages?
4074                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4075                         return array( 'namespace-nosubpages',
4076                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
4077                 }
4078                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4079                         return array( 'namespace-nosubpages',
4080                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
4081                 }
4082
4083                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4084                 $retval = array();
4085                 $count = 0;
4086                 foreach ( $subpages as $oldSubpage ) {
4087                         $count++;
4088                         if ( $count > $wgMaximumMovedPages ) {
4089                                 $retval[$oldSubpage->getPrefixedText()] =
4090                                                 array( 'movepage-max-pages',
4091                                                         $wgMaximumMovedPages );
4092                                 break;
4093                         }
4094
4095                         // We don't know whether this function was called before
4096                         // or after moving the root page, so check both
4097                         // $this and $nt
4098                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4099                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4100                         ) {
4101                                 // When moving a page to a subpage of itself,
4102                                 // don't move it twice
4103                                 continue;
4104                         }
4105                         $newPageName = preg_replace(
4106                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4107                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4108                                         $oldSubpage->getDBkey() );
4109                         if ( $oldSubpage->isTalkPage() ) {
4110                                 $newNs = $nt->getTalkPage()->getNamespace();
4111                         } else {
4112                                 $newNs = $nt->getSubjectPage()->getNamespace();
4113                         }
4114                         # Bug 14385: we need makeTitleSafe because the new page names may
4115                         # be longer than 255 characters.
4116                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4117
4118                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4119                         if ( $success === true ) {
4120                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4121                         } else {
4122                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4123                         }
4124                 }
4125                 return $retval;
4126         }
4127
4128         /**
4129          * Checks if this page is just a one-rev redirect.
4130          * Adds lock, so don't use just for light purposes.
4131          *
4132          * @return bool
4133          */
4134         public function isSingleRevRedirect() {
4135                 global $wgContentHandlerUseDB;
4136
4137                 $dbw = wfGetDB( DB_MASTER );
4138
4139                 # Is it a redirect?
4140                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4141                 if ( $wgContentHandlerUseDB ) {
4142                         $fields[] = 'page_content_model';
4143                 }
4144
4145                 $row = $dbw->selectRow( 'page',
4146                         $fields,
4147                         $this->pageCond(),
4148                         __METHOD__,
4149                         array( 'FOR UPDATE' )
4150                 );
4151                 # Cache some fields we may want
4152                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4153                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4154                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4155                 $this->mContentModel = $row && isset( $row->page_content_model )
4156                         ? strval( $row->page_content_model )
4157                         : false;
4158
4159                 if ( !$this->mRedirect ) {
4160                         return false;
4161                 }
4162                 # Does the article have a history?
4163                 $row = $dbw->selectField( array( 'page', 'revision' ),
4164                         'rev_id',
4165                         array( 'page_namespace' => $this->getNamespace(),
4166                                 'page_title' => $this->getDBkey(),
4167                                 'page_id=rev_page',
4168                                 'page_latest != rev_id'
4169                         ),
4170                         __METHOD__,
4171                         array( 'FOR UPDATE' )
4172                 );
4173                 # Return true if there was no history
4174                 return ( $row === false );
4175         }
4176
4177         /**
4178          * Checks if $this can be moved to a given Title
4179          * - Selects for update, so don't call it unless you mean business
4180          *
4181          * @param Title $nt The new title to check
4182          * @return bool
4183          */
4184         public function isValidMoveTarget( $nt ) {
4185                 # Is it an existing file?
4186                 if ( $nt->getNamespace() == NS_FILE ) {
4187                         $file = wfLocalFile( $nt );
4188                         if ( $file->exists() ) {
4189                                 wfDebug( __METHOD__ . ": file exists\n" );
4190                                 return false;
4191                         }
4192                 }
4193                 # Is it a redirect with no history?
4194                 if ( !$nt->isSingleRevRedirect() ) {
4195                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4196                         return false;
4197                 }
4198                 # Get the article text
4199                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4200                 if ( !is_object( $rev ) ) {
4201                         return false;
4202                 }
4203                 $content = $rev->getContent();
4204                 # Does the redirect point to the source?
4205                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4206                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4207
4208                 if ( $redirTitle ) {
4209                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4210                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4211                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4212                                 return false;
4213                         } else {
4214                                 return true;
4215                         }
4216                 } else {
4217                         # Fail safe (not a redirect after all. strange.)
4218                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4219                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4220                         return false;
4221                 }
4222         }
4223
4224         /**
4225          * Get categories to which this Title belongs and return an array of
4226          * categories' names.
4227          *
4228          * @return array Array of parents in the form:
4229          *        $parent => $currentarticle
4230          */
4231         public function getParentCategories() {
4232                 global $wgContLang;
4233
4234                 $data = array();
4235
4236                 $titleKey = $this->getArticleID();
4237
4238                 if ( $titleKey === 0 ) {
4239                         return $data;
4240                 }
4241
4242                 $dbr = wfGetDB( DB_SLAVE );
4243
4244                 $res = $dbr->select(
4245                         'categorylinks',
4246                         'cl_to',
4247                         array( 'cl_from' => $titleKey ),
4248                         __METHOD__
4249                 );
4250
4251                 if ( $res->numRows() > 0 ) {
4252                         foreach ( $res as $row ) {
4253                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4254                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4255                         }
4256                 }
4257                 return $data;
4258         }
4259
4260         /**
4261          * Get a tree of parent categories
4262          *
4263          * @param array $children Array with the children in the keys, to check for circular refs
4264          * @return array Tree of parent categories
4265          */
4266         public function getParentCategoryTree( $children = array() ) {
4267                 $stack = array();
4268                 $parents = $this->getParentCategories();
4269
4270                 if ( $parents ) {
4271                         foreach ( $parents as $parent => $current ) {
4272                                 if ( array_key_exists( $parent, $children ) ) {
4273                                         # Circular reference
4274                                         $stack[$parent] = array();
4275                                 } else {
4276                                         $nt = Title::newFromText( $parent );
4277                                         if ( $nt ) {
4278                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4279                                         }
4280                                 }
4281                         }
4282                 }
4283
4284                 return $stack;
4285         }
4286
4287         /**
4288          * Get an associative array for selecting this title from
4289          * the "page" table
4290          *
4291          * @return array Array suitable for the $where parameter of DB::select()
4292          */
4293         public function pageCond() {
4294                 if ( $this->mArticleID > 0 ) {
4295                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4296                         return array( 'page_id' => $this->mArticleID );
4297                 } else {
4298                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4299                 }
4300         }
4301
4302         /**
4303          * Get the revision ID of the previous revision
4304          *
4305          * @param int $revId Revision ID. Get the revision that was before this one.
4306          * @param int $flags Title::GAID_FOR_UPDATE
4307          * @return int|bool Old revision ID, or false if none exists
4308          */
4309         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4310                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4311                 $revId = $db->selectField( 'revision', 'rev_id',
4312                         array(
4313                                 'rev_page' => $this->getArticleID( $flags ),
4314                                 'rev_id < ' . intval( $revId )
4315                         ),
4316                         __METHOD__,
4317                         array( 'ORDER BY' => 'rev_id DESC' )
4318                 );
4319
4320                 if ( $revId === false ) {
4321                         return false;
4322                 } else {
4323                         return intval( $revId );
4324                 }
4325         }
4326
4327         /**
4328          * Get the revision ID of the next revision
4329          *
4330          * @param int $revId Revision ID. Get the revision that was after this one.
4331          * @param int $flags Title::GAID_FOR_UPDATE
4332          * @return int|bool Next revision ID, or false if none exists
4333          */
4334         public function getNextRevisionID( $revId, $flags = 0 ) {
4335                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4336                 $revId = $db->selectField( 'revision', 'rev_id',
4337                         array(
4338                                 'rev_page' => $this->getArticleID( $flags ),
4339                                 'rev_id > ' . intval( $revId )
4340                         ),
4341                         __METHOD__,
4342                         array( 'ORDER BY' => 'rev_id' )
4343                 );
4344
4345                 if ( $revId === false ) {
4346                         return false;
4347                 } else {
4348                         return intval( $revId );
4349                 }
4350         }
4351
4352         /**
4353          * Get the first revision of the page
4354          *
4355          * @param int $flags Title::GAID_FOR_UPDATE
4356          * @return Revision|null If page doesn't exist
4357          */
4358         public function getFirstRevision( $flags = 0 ) {
4359                 $pageId = $this->getArticleID( $flags );
4360                 if ( $pageId ) {
4361                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4362                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4363                                 array( 'rev_page' => $pageId ),
4364                                 __METHOD__,
4365                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4366                         );
4367                         if ( $row ) {
4368                                 return new Revision( $row );
4369                         }
4370                 }
4371                 return null;
4372         }
4373
4374         /**
4375          * Get the oldest revision timestamp of this page
4376          *
4377          * @param int $flags Title::GAID_FOR_UPDATE
4378          * @return string MW timestamp
4379          */
4380         public function getEarliestRevTime( $flags = 0 ) {
4381                 $rev = $this->getFirstRevision( $flags );
4382                 return $rev ? $rev->getTimestamp() : null;
4383         }
4384
4385         /**
4386          * Check if this is a new page
4387          *
4388          * @return bool
4389          */
4390         public function isNewPage() {
4391                 $dbr = wfGetDB( DB_SLAVE );
4392                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4393         }
4394
4395         /**
4396          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4397          *
4398          * @return bool
4399          */
4400         public function isBigDeletion() {
4401                 global $wgDeleteRevisionsLimit;
4402
4403                 if ( !$wgDeleteRevisionsLimit ) {
4404                         return false;
4405                 }
4406
4407                 $revCount = $this->estimateRevisionCount();
4408                 return $revCount > $wgDeleteRevisionsLimit;
4409         }
4410
4411         /**
4412          * Get the  approximate revision count of this page.
4413          *
4414          * @return int
4415          */
4416         public function estimateRevisionCount() {
4417                 if ( !$this->exists() ) {
4418                         return 0;
4419                 }
4420
4421                 if ( $this->mEstimateRevisions === null ) {
4422                         $dbr = wfGetDB( DB_SLAVE );
4423                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4424                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4425                 }
4426
4427                 return $this->mEstimateRevisions;
4428         }
4429
4430         /**
4431          * Get the number of revisions between the given revision.
4432          * Used for diffs and other things that really need it.
4433          *
4434          * @param int|Revision $old Old revision or rev ID (first before range)
4435          * @param int|Revision $new New revision or rev ID (first after range)
4436          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4437          * @return int Number of revisions between these revisions.
4438          */
4439         public function countRevisionsBetween( $old, $new, $max = null ) {
4440                 if ( !( $old instanceof Revision ) ) {
4441                         $old = Revision::newFromTitle( $this, (int)$old );
4442                 }
4443                 if ( !( $new instanceof Revision ) ) {
4444                         $new = Revision::newFromTitle( $this, (int)$new );
4445                 }
4446                 if ( !$old || !$new ) {
4447                         return 0; // nothing to compare
4448                 }
4449                 $dbr = wfGetDB( DB_SLAVE );
4450                 $conds = array(
4451                         'rev_page' => $this->getArticleID(),
4452                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4453                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4454                 );
4455                 if ( $max !== null ) {
4456                         $res = $dbr->select( 'revision', '1',
4457                                 $conds,
4458                                 __METHOD__,
4459                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4460                         );
4461                         return $res->numRows();
4462                 } else {
4463                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4464                 }
4465         }
4466
4467         /**
4468          * Get the authors between the given revisions or revision IDs.
4469          * Used for diffs and other things that really need it.
4470          *
4471          * @since 1.23
4472          *
4473          * @param int|Revision $old Old revision or rev ID (first before range by default)
4474          * @param int|Revision $new New revision or rev ID (first after range by default)
4475          * @param int $limit Maximum number of authors
4476          * @param string|array $options (Optional): Single option, or an array of options:
4477          *     'include_old' Include $old in the range; $new is excluded.
4478          *     'include_new' Include $new in the range; $old is excluded.
4479          *     'include_both' Include both $old and $new in the range.
4480          *     Unknown option values are ignored.
4481          * @return array|null Names of revision authors in the range; null if not both revisions exist
4482          */
4483         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4484                 if ( !( $old instanceof Revision ) ) {
4485                         $old = Revision::newFromTitle( $this, (int)$old );
4486                 }
4487                 if ( !( $new instanceof Revision ) ) {
4488                         $new = Revision::newFromTitle( $this, (int)$new );
4489                 }
4490                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4491                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4492                 // in the sanity check below?
4493                 if ( !$old || !$new ) {
4494                         return null; // nothing to compare
4495                 }
4496                 $authors = array();
4497                 $old_cmp = '>';
4498                 $new_cmp = '<';
4499                 $options = (array)$options;
4500                 if ( in_array( 'include_old', $options ) ) {
4501                         $old_cmp = '>=';
4502                 }
4503                 if ( in_array( 'include_new', $options ) ) {
4504                         $new_cmp = '<=';
4505                 }
4506                 if ( in_array( 'include_both', $options ) ) {
4507                         $old_cmp = '>=';
4508                         $new_cmp = '<=';
4509                 }
4510                 // No DB query needed if $old and $new are the same or successive revisions:
4511                 if ( $old->getId() === $new->getId() ) {
4512                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? array() : array( $old->getRawUserText() );
4513                 } elseif ( $old->getId() === $new->getParentId() ) {
4514                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4515                                 $authors[] = $old->getRawUserText();
4516                                 if ( $old->getRawUserText() != $new->getRawUserText() ) {
4517                                         $authors[] = $new->getRawUserText();
4518                                 }
4519                         } elseif ( $old_cmp === '>=' ) {
4520                                 $authors[] = $old->getRawUserText();
4521                         } elseif ( $new_cmp === '<=' ) {
4522                                 $authors[] = $new->getRawUserText();
4523                         }
4524                         return $authors;
4525                 }
4526                 $dbr = wfGetDB( DB_SLAVE );
4527                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4528                         array(
4529                                 'rev_page' => $this->getArticleID(),
4530                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4531                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4532                         ), __METHOD__,
4533                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4534                 );
4535                 foreach ( $res as $row ) {
4536                         $authors[] = $row->rev_user_text;
4537                 }
4538                 return $authors;
4539         }
4540
4541         /**
4542          * Get the number of authors between the given revisions or revision IDs.
4543          * Used for diffs and other things that really need it.
4544          *
4545          * @param int|Revision $old Old revision or rev ID (first before range by default)
4546          * @param int|Revision $new New revision or rev ID (first after range by default)
4547          * @param int $limit Maximum number of authors
4548          * @param string|array $options (Optional): Single option, or an array of options:
4549          *     'include_old' Include $old in the range; $new is excluded.
4550          *     'include_new' Include $new in the range; $old is excluded.
4551          *     'include_both' Include both $old and $new in the range.
4552          *     Unknown option values are ignored.
4553          * @return int Number of revision authors in the range; zero if not both revisions exist
4554          */
4555         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4556                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4557                 return $authors ? count( $authors ) : 0;
4558         }
4559
4560         /**
4561          * Compare with another title.
4562          *
4563          * @param Title $title
4564          * @return bool
4565          */
4566         public function equals( Title $title ) {
4567                 // Note: === is necessary for proper matching of number-like titles.
4568                 return $this->getInterwiki() === $title->getInterwiki()
4569                         && $this->getNamespace() == $title->getNamespace()
4570                         && $this->getDBkey() === $title->getDBkey();
4571         }
4572
4573         /**
4574          * Check if this title is a subpage of another title
4575          *
4576          * @param Title $title
4577          * @return bool
4578          */
4579         public function isSubpageOf( Title $title ) {
4580                 return $this->getInterwiki() === $title->getInterwiki()
4581                         && $this->getNamespace() == $title->getNamespace()
4582                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4583         }
4584
4585         /**
4586          * Check if page exists.  For historical reasons, this function simply
4587          * checks for the existence of the title in the page table, and will
4588          * thus return false for interwiki links, special pages and the like.
4589          * If you want to know if a title can be meaningfully viewed, you should
4590          * probably call the isKnown() method instead.
4591          *
4592          * @return bool
4593          */
4594         public function exists() {
4595                 return $this->getArticleID() != 0;
4596         }
4597
4598         /**
4599          * Should links to this title be shown as potentially viewable (i.e. as
4600          * "bluelinks"), even if there's no record by this title in the page
4601          * table?
4602          *
4603          * This function is semi-deprecated for public use, as well as somewhat
4604          * misleadingly named.  You probably just want to call isKnown(), which
4605          * calls this function internally.
4606          *
4607          * (ISSUE: Most of these checks are cheap, but the file existence check
4608          * can potentially be quite expensive.  Including it here fixes a lot of
4609          * existing code, but we might want to add an optional parameter to skip
4610          * it and any other expensive checks.)
4611          *
4612          * @return bool
4613          */
4614         public function isAlwaysKnown() {
4615                 $isKnown = null;
4616
4617                 /**
4618                  * Allows overriding default behavior for determining if a page exists.
4619                  * If $isKnown is kept as null, regular checks happen. If it's
4620                  * a boolean, this value is returned by the isKnown method.
4621                  *
4622                  * @since 1.20
4623                  *
4624                  * @param Title $title
4625                  * @param bool|null $isKnown
4626                  */
4627                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4628
4629                 if ( !is_null( $isKnown ) ) {
4630                         return $isKnown;
4631                 }
4632
4633                 if ( $this->isExternal() ) {
4634                         return true;  // any interwiki link might be viewable, for all we know
4635                 }
4636
4637                 switch ( $this->mNamespace ) {
4638                         case NS_MEDIA:
4639                         case NS_FILE:
4640                                 // file exists, possibly in a foreign repo
4641                                 return (bool)wfFindFile( $this );
4642                         case NS_SPECIAL:
4643                                 // valid special page
4644                                 return SpecialPageFactory::exists( $this->getDBkey() );
4645                         case NS_MAIN:
4646                                 // selflink, possibly with fragment
4647                                 return $this->mDbkeyform == '';
4648                         case NS_MEDIAWIKI:
4649                                 // known system message
4650                                 return $this->hasSourceText() !== false;
4651                         default:
4652                                 return false;
4653                 }
4654         }
4655
4656         /**
4657          * Does this title refer to a page that can (or might) be meaningfully
4658          * viewed?  In particular, this function may be used to determine if
4659          * links to the title should be rendered as "bluelinks" (as opposed to
4660          * "redlinks" to non-existent pages).
4661          * Adding something else to this function will cause inconsistency
4662          * since LinkHolderArray calls isAlwaysKnown() and does its own
4663          * page existence check.
4664          *
4665          * @return bool
4666          */
4667         public function isKnown() {
4668                 return $this->isAlwaysKnown() || $this->exists();
4669         }
4670
4671         /**
4672          * Does this page have source text?
4673          *
4674          * @return bool
4675          */
4676         public function hasSourceText() {
4677                 if ( $this->exists() ) {
4678                         return true;
4679                 }
4680
4681                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4682                         // If the page doesn't exist but is a known system message, default
4683                         // message content will be displayed, same for language subpages-
4684                         // Use always content language to avoid loading hundreds of languages
4685                         // to get the link color.
4686                         global $wgContLang;
4687                         list( $name, ) = MessageCache::singleton()->figureMessage(
4688                                 $wgContLang->lcfirst( $this->getText() )
4689                         );
4690                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4691                         return $message->exists();
4692                 }
4693
4694                 return false;
4695         }
4696
4697         /**
4698          * Get the default message text or false if the message doesn't exist
4699          *
4700          * @return string|bool
4701          */
4702         public function getDefaultMessageText() {
4703                 global $wgContLang;
4704
4705                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4706                         return false;
4707                 }
4708
4709                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4710                         $wgContLang->lcfirst( $this->getText() )
4711                 );
4712                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4713
4714                 if ( $message->exists() ) {
4715                         return $message->plain();
4716                 } else {
4717                         return false;
4718                 }
4719         }
4720
4721         /**
4722          * Updates page_touched for this page; called from LinksUpdate.php
4723          *
4724          * @return bool True if the update succeeded
4725          */
4726         public function invalidateCache() {
4727                 if ( wfReadOnly() ) {
4728                         return false;
4729                 }
4730
4731                 $method = __METHOD__;
4732                 $dbw = wfGetDB( DB_MASTER );
4733                 $conds = $this->pageCond();
4734                 $dbw->onTransactionIdle( function() use ( $dbw, $conds, $method ) {
4735                         $dbw->update(
4736                                 'page',
4737                                 array( 'page_touched' => $dbw->timestamp() ),
4738                                 $conds,
4739                                 $method
4740                         );
4741                 } );
4742
4743                 return true;
4744         }
4745
4746         /**
4747          * Update page_touched timestamps and send squid purge messages for
4748          * pages linking to this title. May be sent to the job queue depending
4749          * on the number of links. Typically called on create and delete.
4750          */
4751         public function touchLinks() {
4752                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4753                 $u->doUpdate();
4754
4755                 if ( $this->getNamespace() == NS_CATEGORY ) {
4756                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4757                         $u->doUpdate();
4758                 }
4759         }
4760
4761         /**
4762          * Get the last touched timestamp
4763          *
4764          * @param DatabaseBase $db Optional db
4765          * @return string Last-touched timestamp
4766          */
4767         public function getTouched( $db = null ) {
4768                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
4769                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4770                 return $touched;
4771         }
4772
4773         /**
4774          * Get the timestamp when this page was updated since the user last saw it.
4775          *
4776          * @param User $user
4777          * @return string|null
4778          */
4779         public function getNotificationTimestamp( $user = null ) {
4780                 global $wgUser, $wgShowUpdatedMarker;
4781                 // Assume current user if none given
4782                 if ( !$user ) {
4783                         $user = $wgUser;
4784                 }
4785                 // Check cache first
4786                 $uid = $user->getId();
4787                 // avoid isset here, as it'll return false for null entries
4788                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4789                         return $this->mNotificationTimestamp[$uid];
4790                 }
4791                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4792                         $this->mNotificationTimestamp[$uid] = false;
4793                         return $this->mNotificationTimestamp[$uid];
4794                 }
4795                 // Don't cache too much!
4796                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4797                         $this->mNotificationTimestamp = array();
4798                 }
4799                 $dbr = wfGetDB( DB_SLAVE );
4800                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4801                         'wl_notificationtimestamp',
4802                         array(
4803                                 'wl_user' => $user->getId(),
4804                                 'wl_namespace' => $this->getNamespace(),
4805                                 'wl_title' => $this->getDBkey(),
4806                         ),
4807                         __METHOD__
4808                 );
4809                 return $this->mNotificationTimestamp[$uid];
4810         }
4811
4812         /**
4813          * Generate strings used for xml 'id' names in monobook tabs
4814          *
4815          * @param string $prepend Defaults to 'nstab-'
4816          * @return string XML 'id' name
4817          */
4818         public function getNamespaceKey( $prepend = 'nstab-' ) {
4819                 global $wgContLang;
4820                 // Gets the subject namespace if this title
4821                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4822                 // Checks if canonical namespace name exists for namespace
4823                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4824                         // Uses canonical namespace name
4825                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4826                 } else {
4827                         // Uses text of namespace
4828                         $namespaceKey = $this->getSubjectNsText();
4829                 }
4830                 // Makes namespace key lowercase
4831                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4832                 // Uses main
4833                 if ( $namespaceKey == '' ) {
4834                         $namespaceKey = 'main';
4835                 }
4836                 // Changes file to image for backwards compatibility
4837                 if ( $namespaceKey == 'file' ) {
4838                         $namespaceKey = 'image';
4839                 }
4840                 return $prepend . $namespaceKey;
4841         }
4842
4843         /**
4844          * Get all extant redirects to this Title
4845          *
4846          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4847          * @return Title[] Array of Title redirects to this title
4848          */
4849         public function getRedirectsHere( $ns = null ) {
4850                 $redirs = array();
4851
4852                 $dbr = wfGetDB( DB_SLAVE );
4853                 $where = array(
4854                         'rd_namespace' => $this->getNamespace(),
4855                         'rd_title' => $this->getDBkey(),
4856                         'rd_from = page_id'
4857                 );
4858                 if ( $this->isExternal() ) {
4859                         $where['rd_interwiki'] = $this->getInterwiki();
4860                 } else {
4861                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4862                 }
4863                 if ( !is_null( $ns ) ) {
4864                         $where['page_namespace'] = $ns;
4865                 }
4866
4867                 $res = $dbr->select(
4868                         array( 'redirect', 'page' ),
4869                         array( 'page_namespace', 'page_title' ),
4870                         $where,
4871                         __METHOD__
4872                 );
4873
4874                 foreach ( $res as $row ) {
4875                         $redirs[] = self::newFromRow( $row );
4876                 }
4877                 return $redirs;
4878         }
4879
4880         /**
4881          * Check if this Title is a valid redirect target
4882          *
4883          * @return bool
4884          */
4885         public function isValidRedirectTarget() {
4886                 global $wgInvalidRedirectTargets;
4887
4888                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4889                 if ( $this->isSpecial( 'Userlogout' ) ) {
4890                         return false;
4891                 }
4892
4893                 foreach ( $wgInvalidRedirectTargets as $target ) {
4894                         if ( $this->isSpecial( $target ) ) {
4895                                 return false;
4896                         }
4897                 }
4898
4899                 return true;
4900         }
4901
4902         /**
4903          * Get a backlink cache object
4904          *
4905          * @return BacklinkCache
4906          */
4907         public function getBacklinkCache() {
4908                 return BacklinkCache::get( $this );
4909         }
4910
4911         /**
4912          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4913          *
4914          * @return bool
4915          */
4916         public function canUseNoindex() {
4917                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4918
4919                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4920                         ? $wgContentNamespaces
4921                         : $wgExemptFromUserRobotsControl;
4922
4923                 return !in_array( $this->mNamespace, $bannedNamespaces );
4924
4925         }
4926
4927         /**
4928          * Returns the raw sort key to be used for categories, with the specified
4929          * prefix.  This will be fed to Collation::getSortKey() to get a
4930          * binary sortkey that can be used for actual sorting.
4931          *
4932          * @param string $prefix The prefix to be used, specified using
4933          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4934          *   prefix.
4935          * @return string
4936          */
4937         public function getCategorySortkey( $prefix = '' ) {
4938                 $unprefixed = $this->getText();
4939
4940                 // Anything that uses this hook should only depend
4941                 // on the Title object passed in, and should probably
4942                 // tell the users to run updateCollations.php --force
4943                 // in order to re-sort existing category relations.
4944                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4945                 if ( $prefix !== '' ) {
4946                         # Separate with a line feed, so the unprefixed part is only used as
4947                         # a tiebreaker when two pages have the exact same prefix.
4948                         # In UCA, tab is the only character that can sort above LF
4949                         # so we strip both of them from the original prefix.
4950                         $prefix = strtr( $prefix, "\n\t", '  ' );
4951                         return "$prefix\n$unprefixed";
4952                 }
4953                 return $unprefixed;
4954         }
4955
4956         /**
4957          * Get the language in which the content of this page is written in
4958          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4959          * e.g. $wgLang (such as special pages, which are in the user language).
4960          *
4961          * @since 1.18
4962          * @return Language
4963          */
4964         public function getPageLanguage() {
4965                 global $wgLang, $wgLanguageCode;
4966                 wfProfileIn( __METHOD__ );
4967                 if ( $this->isSpecialPage() ) {
4968                         // special pages are in the user language
4969                         wfProfileOut( __METHOD__ );
4970                         return $wgLang;
4971                 }
4972
4973                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4974                         // Note that this may depend on user settings, so the cache should
4975                         // be only per-request.
4976                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4977                         // content to determine the page language!
4978                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4979                         // tests.
4980                         $contentHandler = ContentHandler::getForTitle( $this );
4981                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4982                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4983                 } else {
4984                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4985                 }
4986                 wfProfileOut( __METHOD__ );
4987                 return $langObj;
4988         }
4989
4990         /**
4991          * Get the language in which the content of this page is written when
4992          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4993          * e.g. $wgLang (such as special pages, which are in the user language).
4994          *
4995          * @since 1.20
4996          * @return Language
4997          */
4998         public function getPageViewLanguage() {
4999                 global $wgLang;
5000
5001                 if ( $this->isSpecialPage() ) {
5002                         // If the user chooses a variant, the content is actually
5003                         // in a language whose code is the variant code.
5004                         $variant = $wgLang->getPreferredVariant();
5005                         if ( $wgLang->getCode() !== $variant ) {
5006                                 return Language::factory( $variant );
5007                         }
5008
5009                         return $wgLang;
5010                 }
5011
5012                 // @note Can't be cached persistently, depends on user settings.
5013                 // @note ContentHandler::getPageViewLanguage() may need to load the
5014                 //   content to determine the page language!
5015                 $contentHandler = ContentHandler::getForTitle( $this );
5016                 $pageLang = $contentHandler->getPageViewLanguage( $this );
5017                 return $pageLang;
5018         }
5019
5020         /**
5021          * Get a list of rendered edit notices for this page.
5022          *
5023          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
5024          * they will already be wrapped in paragraphs.
5025          *
5026          * @since 1.21
5027          * @param int $oldid Revision ID that's being edited
5028          * @return array
5029          */
5030         public function getEditNotices( $oldid = 0 ) {
5031                 $notices = array();
5032
5033                 # Optional notices on a per-namespace and per-page basis
5034                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
5035                 $editnotice_ns_message = wfMessage( $editnotice_ns );
5036                 if ( $editnotice_ns_message->exists() ) {
5037                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
5038                 }
5039                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
5040                         $parts = explode( '/', $this->getDBkey() );
5041                         $editnotice_base = $editnotice_ns;
5042                         while ( count( $parts ) > 0 ) {
5043                                 $editnotice_base .= '-' . array_shift( $parts );
5044                                 $editnotice_base_msg = wfMessage( $editnotice_base );
5045                                 if ( $editnotice_base_msg->exists() ) {
5046                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
5047                                 }
5048                         }
5049                 } else {
5050                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
5051                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
5052                         $editnoticeMsg = wfMessage( $editnoticeText );
5053                         if ( $editnoticeMsg->exists() ) {
5054                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
5055                         }
5056                 }
5057
5058                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
5059                 return $notices;
5060         }
5061 }