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         private $mHasSubpages;
 149
 150         /** @var bool The (string) language code of the page's language and content code. */
 151         private $mPageLanguage = false;
 152
 153         /** @var string The page language code from the database */
 154         private $mDbPageLanguage = null;
 155
 156         /** @var TitleValue A corresponding TitleValue object */
 157         private $mTitleValue = null;
 158         // @}
 159
 160         /**
 161          * B/C kludge: provide a TitleParser for use by Title.
 162          * Ideally, Title would have no methods that need this.
 163          * Avoid usage of this singleton by using TitleValue
 164          * and the associated services when possible.
 165          *
 166          * @return TitleParser
 167          */
 168         private static function getTitleParser() {
 169                 global $wgContLang, $wgLocalInterwikis;
 170
 171                 static $titleCodec = null;
 172                 static $titleCodecFingerprint = null;
 173
 174                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 175                 // make sure we are using the right one. To detect changes over the course
 176                 // of a request, we remember a fingerprint of the config used to create the
 177                 // codec singleton, and re-create it if the fingerprint doesn't match.
 178                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . join( '+', $wgLocalInterwikis );
 179
 180                 if ( $fingerprint !== $titleCodecFingerprint ) {
 181                         $titleCodec = null;
 182                 }
 183
 184                 if ( !$titleCodec ) {
 185                         $titleCodec = new MediaWikiTitleCodec(
 186                                 $wgContLang,
 187                                 GenderCache::singleton(),
 188                                 $wgLocalInterwikis
 189                         );
 190                         $titleCodecFingerprint = $fingerprint;
 191                 }
 192
 193                 return $titleCodec;
 194         }
 195
 196         /**
 197          * B/C kludge: provide a TitleParser for use by Title.
 198          * Ideally, Title would have no methods that need this.
 199          * Avoid usage of this singleton by using TitleValue
 200          * and the associated services when possible.
 201          *
 202          * @return TitleFormatter
 203          */
 204         private static function getTitleFormatter() {
 205                 //NOTE: we know that getTitleParser() returns a MediaWikiTitleCodec,
 206                 //      which implements TitleFormatter.
 207                 return self::getTitleParser();
 208         }
 209
 210         function __construct() {
 211         }
 212
 213         /**
 214          * Create a new Title from a prefixed DB key
 215          *
 216          * @param string $key The database key, which has underscores
 217          *      instead of spaces, possibly including namespace and
 218          *      interwiki prefixes
 219          * @return Title|null Title, or null on an error
 220          */
 221         public static function newFromDBkey( $key ) {
 222                 $t = new Title();
 223                 $t->mDbkeyform = $key;
 224                 if ( $t->secureAndSplit() ) {
 225                         return $t;
 226                 } else {
 227                         return null;
 228                 }
 229         }
 230
 231         /**
 232          * Create a new Title from a TitleValue
 233          *
 234          * @param TitleValue $titleValue Assumed to be safe.
 235          *
 236          * @return Title
 237          */
 238         public static function newFromTitleValue( TitleValue $titleValue ) {
 239                 return self::makeTitle(
 240                         $titleValue->getNamespace(),
 241                         $titleValue->getText(),
 242                         $titleValue->getFragment() );
 243         }
 244
 245         /**
 246          * Create a new Title from text, such as what one would find in a link. De-
 247          * codes any HTML entities in the text.
 248          *
 249          * @param string $text The link text; spaces, prefixes, and an
 250          *   initial ':' indicating the main namespace are accepted.
 251          * @param int $defaultNamespace The namespace to use if none is specified
 252          *   by a prefix.  If you want to force a specific namespace even if
 253          *   $text might begin with a namespace prefix, use makeTitle() or
 254          *   makeTitleSafe().
 255          * @throws MWException
 256          * @return Title|null Title or null on an error.
 257          */
 258         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 259                 if ( is_object( $text ) ) {
 260                         throw new MWException( 'Title::newFromText given an object' );
 261                 }
 262
 263                 $cache = self::getTitleCache();
 264
 265                 /**
 266                  * Wiki pages often contain multiple links to the same page.
 267                  * Title normalization and parsing can become expensive on
 268                  * pages with many links, so we can save a little time by
 269                  * caching them.
 270                  *
 271                  * In theory these are value objects and won't get changed...
 272                  */
 273                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 274                         return $cache->get( $text );
 275                 }
 276
 277                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 278                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 279
 280                 $t = new Title();
 281                 $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
 282                 $t->mDefaultNamespace = intval( $defaultNamespace );
 283
 284                 if ( $t->secureAndSplit() ) {
 285                         if ( $defaultNamespace == NS_MAIN ) {
 286                                 $cache->set( $text, $t );
 287                         }
 288                         return $t;
 289                 } else {
 290                         return null;
 291                 }
 292         }
 293
 294         /**
 295          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 296          *
 297          * Example of wrong and broken code:
 298          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 299          *
 300          * Example of right code:
 301          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 302          *
 303          * Create a new Title from URL-encoded text. Ensures that
 304          * the given title's length does not exceed the maximum.
 305          *
 306          * @param string $url The title, as might be taken from a URL
 307          * @return Title|null The new object, or null on an error
 308          */
 309         public static function newFromURL( $url ) {
 310                 $t = new Title();
 311
 312                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 313                 # but some URLs used it as a space replacement and they still come
 314                 # from some external search tools.
 315                 if ( strpos( self::legalChars(), '+' ) === false ) {
 316                         $url = str_replace( '+', ' ', $url );
 317                 }
 318
 319                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 320                 if ( $t->secureAndSplit() ) {
 321                         return $t;
 322                 } else {
 323                         return null;
 324                 }
 325         }
 326
 327         /**
 328          * @return MapCacheLRU
 329          */
 330         private static function getTitleCache() {
 331                 if ( self::$titleCache == null ) {
 332                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 333                 }
 334                 return self::$titleCache;
 335         }
 336
 337         /**
 338          * Returns a list of fields that are to be selected for initializing Title
 339          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 340          * whether to include page_content_model.
 341          *
 342          * @return array
 343          */
 344         protected static function getSelectFields() {
 345                 global $wgContentHandlerUseDB;
 346
 347                 $fields = array(
 348                         'page_namespace', 'page_title', 'page_id',
 349                         'page_len', 'page_is_redirect', 'page_latest',
 350                 );
 351
 352                 if ( $wgContentHandlerUseDB ) {
 353                         $fields[] = 'page_content_model';
 354                 }
 355
 356                 return $fields;
 357         }
 358
 359         /**
 360          * Create a new Title from an article ID
 361          *
 362          * @param int $id The page_id corresponding to the Title to create
 363          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 364          * @return Title|null The new object, or null on an error
 365          */
 366         public static function newFromID( $id, $flags = 0 ) {
 367                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 368                 $row = $db->selectRow(
 369                         'page',
 370                         self::getSelectFields(),
 371                         array( 'page_id' => $id ),
 372                         __METHOD__
 373                 );
 374                 if ( $row !== false ) {
 375                         $title = Title::newFromRow( $row );
 376                 } else {
 377                         $title = null;
 378                 }
 379                 return $title;
 380         }
 381
 382         /**
 383          * Make an array of titles from an array of IDs
 384          *
 385          * @param int[] $ids Array of IDs
 386          * @return Title[] Array of Titles
 387          */
 388         public static function newFromIDs( $ids ) {
 389                 if ( !count( $ids ) ) {
 390                         return array();
 391                 }
 392                 $dbr = wfGetDB( DB_SLAVE );
 393
 394                 $res = $dbr->select(
 395                         'page',
 396                         self::getSelectFields(),
 397                         array( 'page_id' => $ids ),
 398                         __METHOD__
 399                 );
 400
 401                 $titles = array();
 402                 foreach ( $res as $row ) {
 403                         $titles[] = Title::newFromRow( $row );
 404                 }
 405                 return $titles;
 406         }
 407
 408         /**
 409          * Make a Title object from a DB row
 410          *
 411          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 412          * @return Title Corresponding Title
 413          */
 414         public static function newFromRow( $row ) {
 415                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 416                 $t->loadFromRow( $row );
 417                 return $t;
 418         }
 419
 420         /**
 421          * Load Title object fields from a DB row.
 422          * If false is given, the title will be treated as non-existing.
 423          *
 424          * @param stdClass|bool $row Database row
 425          */
 426         public function loadFromRow( $row ) {
 427                 if ( $row ) { // page found
 428                         if ( isset( $row->page_id ) ) {
 429                                 $this->mArticleID = (int)$row->page_id;
 430                         }
 431                         if ( isset( $row->page_len ) ) {
 432                                 $this->mLength = (int)$row->page_len;
 433                         }
 434                         if ( isset( $row->page_is_redirect ) ) {
 435                                 $this->mRedirect = (bool)$row->page_is_redirect;
 436                         }
 437                         if ( isset( $row->page_latest ) ) {
 438                                 $this->mLatestID = (int)$row->page_latest;
 439                         }
 440                         if ( isset( $row->page_content_model ) ) {
 441                                 $this->mContentModel = strval( $row->page_content_model );
 442                         } else {
 443                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 444                         }
 445                         if ( isset( $row->page_lang ) ) {
 446                                 $this->mDbPageLanguage = (string)$row->page_lang;
 447                         }
 448                 } else { // page not found
 449                         $this->mArticleID = 0;
 450                         $this->mLength = 0;
 451                         $this->mRedirect = false;
 452                         $this->mLatestID = 0;
 453                         $this->mContentModel = false; # initialized lazily in getContentModel()
 454                 }
 455         }
 456
 457         /**
 458          * Create a new Title from a namespace index and a DB key.
 459          * It's assumed that $ns and $title are *valid*, for instance when
 460          * they came directly from the database or a special page name.
 461          * For convenience, spaces are converted to underscores so that
 462          * eg user_text fields can be used directly.
 463          *
 464          * @param int $ns The namespace of the article
 465          * @param string $title The unprefixed database key form
 466          * @param string $fragment The link fragment (after the "#")
 467          * @param string $interwiki The interwiki prefix
 468          * @return Title The new object
 469          */
 470         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 471                 $t = new Title();
 472                 $t->mInterwiki = $interwiki;
 473                 $t->mFragment = $fragment;
 474                 $t->mNamespace = $ns = intval( $ns );
 475                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 476                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 477                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 478                 $t->mTextform = str_replace( '_', ' ', $title );
 479                 $t->mContentModel = false; # initialized lazily in getContentModel()
 480                 return $t;
 481         }
 482
 483         /**
 484          * Create a new Title from a namespace index and a DB key.
 485          * The parameters will be checked for validity, which is a bit slower
 486          * than makeTitle() but safer for user-provided data.
 487          *
 488          * @param int $ns The namespace of the article
 489          * @param string $title Database key form
 490          * @param string $fragment The link fragment (after the "#")
 491          * @param string $interwiki Interwiki prefix
 492          * @return Title The new object, or null on an error
 493          */
 494         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 495                 if ( !MWNamespace::exists( $ns ) ) {
 496                         return null;
 497                 }
 498
 499                 $t = new Title();
 500                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 501                 if ( $t->secureAndSplit() ) {
 502                         return $t;
 503                 } else {
 504                         return null;
 505                 }
 506         }
 507
 508         /**
 509          * Create a new Title for the Main Page
 510          *
 511          * @return Title The new object
 512          */
 513         public static function newMainPage() {
 514                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 515                 // Don't give fatal errors if the message is broken
 516                 if ( !$title ) {
 517                         $title = Title::newFromText( 'Main Page' );
 518                 }
 519                 return $title;
 520         }
 521
 522         /**
 523          * Extract a redirect destination from a string and return the
 524          * Title, or null if the text doesn't contain a valid redirect
 525          * This will only return the very next target, useful for
 526          * the redirect table and other checks that don't need full recursion
 527          *
 528          * @param string $text Text with possible redirect
 529          * @return Title The corresponding Title
 530          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 531          */
 532         public static function newFromRedirect( $text ) {
 533                 ContentHandler::deprecated( __METHOD__, '1.21' );
 534
 535                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 536                 return $content->getRedirectTarget();
 537         }
 538
 539         /**
 540          * Extract a redirect destination from a string and return the
 541          * Title, or null if the text doesn't contain a valid redirect
 542          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 543          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 544          *
 545          * @param string $text Text with possible redirect
 546          * @return Title
 547          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 548          */
 549         public static function newFromRedirectRecurse( $text ) {
 550                 ContentHandler::deprecated( __METHOD__, '1.21' );
 551
 552                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 553                 return $content->getUltimateRedirectTarget();
 554         }
 555
 556         /**
 557          * Extract a redirect destination from a string and return an
 558          * array of Titles, or null if the text doesn't contain a valid redirect
 559          * The last element in the array is the final destination after all redirects
 560          * have been resolved (up to $wgMaxRedirects times)
 561          *
 562          * @param string $text Text with possible redirect
 563          * @return Title[] Array of Titles, with the destination last
 564          * @deprecated since 1.21, use Content::getRedirectChain instead.
 565          */
 566         public static function newFromRedirectArray( $text ) {
 567                 ContentHandler::deprecated( __METHOD__, '1.21' );
 568
 569                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 570                 return $content->getRedirectChain();
 571         }
 572
 573         /**
 574          * Get the prefixed DB key associated with an ID
 575          *
 576          * @param int $id The page_id of the article
 577          * @return Title|null An object representing the article, or null if no such article was found
 578          */
 579         public static function nameOf( $id ) {
 580                 $dbr = wfGetDB( DB_SLAVE );
 581
 582                 $s = $dbr->selectRow(
 583                         'page',
 584                         array( 'page_namespace', 'page_title' ),
 585                         array( 'page_id' => $id ),
 586                         __METHOD__
 587                 );
 588                 if ( $s === false ) {
 589                         return null;
 590                 }
 591
 592                 $n = self::makeName( $s->page_namespace, $s->page_title );
 593                 return $n;
 594         }
 595
 596         /**
 597          * Get a regex character class describing the legal characters in a link
 598          *
 599          * @return string The list of characters, not delimited
 600          */
 601         public static function legalChars() {
 602                 global $wgLegalTitleChars;
 603                 return $wgLegalTitleChars;
 604         }
 605
 606         /**
 607          * Returns a simple regex that will match on characters and sequences invalid in titles.
 608          * Note that this doesn't pick up many things that could be wrong with titles, but that
 609          * replacing this regex with something valid will make many titles valid.
 610          *
 611          * @todo: move this into MediaWikiTitleCodec
 612          *
 613          * @return string Regex string
 614          */
 615         static function getTitleInvalidRegex() {
 616                 static $rxTc = false;
 617                 if ( !$rxTc ) {
 618                         # Matching titles will be held as illegal.
 619                         $rxTc = '/' .
 620                                 # Any character not allowed is forbidden...
 621                                 '[^' . self::legalChars() . ']' .
 622                                 # URL percent encoding sequences interfere with the ability
 623                                 # to round-trip titles -- you can't link to them consistently.
 624                                 '|%[0-9A-Fa-f]{2}' .
 625                                 # XML/HTML character references produce similar issues.
 626                                 '|&[A-Za-z0-9\x80-\xff]+;' .
 627                                 '|&#[0-9]+;' .
 628                                 '|&#x[0-9A-Fa-f]+;' .
 629                                 '/S';
 630                 }
 631
 632                 return $rxTc;
 633         }
 634
 635         /**
 636          * Utility method for converting a character sequence from bytes to Unicode.
 637          *
 638          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 639          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 640          *
 641          * @param string $byteClass
 642          * @return string
 643          */
 644         public static function convertByteClassToUnicodeClass( $byteClass ) {
 645                 $length = strlen( $byteClass );
 646                 // Input token queue
 647                 $x0 = $x1 = $x2 = '';
 648                 // Decoded queue
 649                 $d0 = $d1 = $d2 = '';
 650                 // Decoded integer codepoints
 651                 $ord0 = $ord1 = $ord2 = 0;
 652                 // Re-encoded queue
 653                 $r0 = $r1 = $r2 = '';
 654                 // Output
 655                 $out = '';
 656                 // Flags
 657                 $allowUnicode = false;
 658                 for ( $pos = 0; $pos < $length; $pos++ ) {
 659                         // Shift the queues down
 660                         $x2 = $x1;
 661                         $x1 = $x0;
 662                         $d2 = $d1;
 663                         $d1 = $d0;
 664                         $ord2 = $ord1;
 665                         $ord1 = $ord0;
 666                         $r2 = $r1;
 667                         $r1 = $r0;
 668                         // Load the current input token and decoded values
 669                         $inChar = $byteClass[$pos];
 670                         if ( $inChar == '\\' ) {
 671                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 672                                         $x0 = $inChar . $m[0];
 673                                         $d0 = chr( hexdec( $m[1] ) );
 674                                         $pos += strlen( $m[0] );
 675                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 676                                         $x0 = $inChar . $m[0];
 677                                         $d0 = chr( octdec( $m[0] ) );
 678                                         $pos += strlen( $m[0] );
 679                                 } elseif ( $pos + 1 >= $length ) {
 680                                         $x0 = $d0 = '\\';
 681                                 } else {
 682                                         $d0 = $byteClass[$pos + 1];
 683                                         $x0 = $inChar . $d0;
 684                                         $pos += 1;
 685                                 }
 686                         } else {
 687                                 $x0 = $d0 = $inChar;
 688                         }
 689                         $ord0 = ord( $d0 );
 690                         // Load the current re-encoded value
 691                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 692                                 $r0 = sprintf( '\x%02x', $ord0 );
 693                         } elseif ( $ord0 >= 0x80 ) {
 694                                 // Allow unicode if a single high-bit character appears
 695                                 $r0 = sprintf( '\x%02x', $ord0 );
 696                                 $allowUnicode = true;
 697                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 698                                 $r0 = '\\' . $d0;
 699                         } else {
 700                                 $r0 = $d0;
 701                         }
 702                         // Do the output
 703                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 704                                 // Range
 705                                 if ( $ord2 > $ord0 ) {
 706                                         // Empty range
 707                                 } elseif ( $ord0 >= 0x80 ) {
 708                                         // Unicode range
 709                                         $allowUnicode = true;
 710                                         if ( $ord2 < 0x80 ) {
 711                                                 // Keep the non-unicode section of the range
 712                                                 $out .= "$r2-\\x7F";
 713                                         }
 714                                 } else {
 715                                         // Normal range
 716                                         $out .= "$r2-$r0";
 717                                 }
 718                                 // Reset state to the initial value
 719                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 720                         } elseif ( $ord2 < 0x80 ) {
 721                                 // ASCII character
 722                                 $out .= $r2;
 723                         }
 724                 }
 725                 if ( $ord1 < 0x80 ) {
 726                         $out .= $r1;
 727                 }
 728                 if ( $ord0 < 0x80 ) {
 729                         $out .= $r0;
 730                 }
 731                 if ( $allowUnicode ) {
 732                         $out .= '\u0080-\uFFFF';
 733                 }
 734                 return $out;
 735         }
 736
 737         /**
 738          * Make a prefixed DB key from a DB key and a namespace index
 739          *
 740          * @param int $ns Numerical representation of the namespace
 741          * @param string $title The DB key form the title
 742          * @param string $fragment The link fragment (after the "#")
 743          * @param string $interwiki The interwiki prefix
 744          * @return string The prefixed form of the title
 745          */
 746         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 747                 global $wgContLang;
 748
 749                 $namespace = $wgContLang->getNsText( $ns );
 750                 $name = $namespace == '' ? $title : "$namespace:$title";
 751                 if ( strval( $interwiki ) != '' ) {
 752                         $name = "$interwiki:$name";
 753                 }
 754                 if ( strval( $fragment ) != '' ) {
 755                         $name .= '#' . $fragment;
 756                 }
 757                 return $name;
 758         }
 759
 760         /**
 761          * Escape a text fragment, say from a link, for a URL
 762          *
 763          * @param string $fragment Containing a URL or link fragment (after the "#")
 764          * @return string Escaped string
 765          */
 766         static function escapeFragmentForURL( $fragment ) {
 767                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 768                 # fragments appear not to work in IE (at least up to 7) or in at least
 769                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 770                 # to care if they aren't encoded.
 771                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 772         }
 773
 774         /**
 775          * Callback for usort() to do title sorts by (namespace, title)
 776          *
 777          * @param Title $a
 778          * @param Title $b
 779          *
 780          * @return int Result of string comparison, or namespace comparison
 781          */
 782         public static function compare( $a, $b ) {
 783                 if ( $a->getNamespace() == $b->getNamespace() ) {
 784                         return strcmp( $a->getText(), $b->getText() );
 785                 } else {
 786                         return $a->getNamespace() - $b->getNamespace();
 787                 }
 788         }
 789
 790         /**
 791          * Determine whether the object refers to a page within
 792          * this project.
 793          *
 794          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 795          */
 796         public function isLocal() {
 797                 if ( $this->isExternal() ) {
 798                         $iw = Interwiki::fetch( $this->mInterwiki );
 799                         if ( $iw ) {
 800                                 return $iw->isLocal();
 801                         }
 802                 }
 803                 return true;
 804         }
 805
 806         /**
 807          * Is this Title interwiki?
 808          *
 809          * @return bool
 810          */
 811         public function isExternal() {
 812                 return $this->mInterwiki !== '';
 813         }
 814
 815         /**
 816          * Get the interwiki prefix
 817          *
 818          * Use Title::isExternal to check if a interwiki is set
 819          *
 820          * @return string Interwiki prefix
 821          */
 822         public function getInterwiki() {
 823                 return $this->mInterwiki;
 824         }
 825
 826         /**
 827          * Determine whether the object refers to a page within
 828          * this project and is transcludable.
 829          *
 830          * @return bool True if this is transcludable
 831          */
 832         public function isTrans() {
 833                 if ( !$this->isExternal() ) {
 834                         return false;
 835                 }
 836
 837                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 838         }
 839
 840         /**
 841          * Returns the DB name of the distant wiki which owns the object.
 842          *
 843          * @return string The DB name
 844          */
 845         public function getTransWikiID() {
 846                 if ( !$this->isExternal() ) {
 847                         return false;
 848                 }
 849
 850                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 851         }
 852
 853         /**
 854          * Get a TitleValue object representing this Title.
 855          *
 856          * @note: Not all valid Titles have a corresponding valid TitleValue
 857          * (e.g. TitleValues cannot represent page-local links that have a
 858          * fragment but no title text).
 859          *
 860          * @return TitleValue|null
 861          */
 862         public function getTitleValue() {
 863                 if ( $this->mTitleValue === null ) {
 864                         try {
 865                                 $this->mTitleValue = new TitleValue(
 866                                         $this->getNamespace(),
 867                                         $this->getDBkey(),
 868                                         $this->getFragment() );
 869                         } catch ( InvalidArgumentException $ex ) {
 870                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 871                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 872                         }
 873                 }
 874
 875                 return $this->mTitleValue;
 876         }
 877
 878         /**
 879          * Get the text form (spaces not underscores) of the main part
 880          *
 881          * @return string Main part of the title
 882          */
 883         public function getText() {
 884                 return $this->mTextform;
 885         }
 886
 887         /**
 888          * Get the URL-encoded form of the main part
 889          *
 890          * @return string Main part of the title, URL-encoded
 891          */
 892         public function getPartialURL() {
 893                 return $this->mUrlform;
 894         }
 895
 896         /**
 897          * Get the main part with underscores
 898          *
 899          * @return string Main part of the title, with underscores
 900          */
 901         public function getDBkey() {
 902                 return $this->mDbkeyform;
 903         }
 904
 905         /**
 906          * Get the DB key with the initial letter case as specified by the user
 907          *
 908          * @return string DB key
 909          */
 910         function getUserCaseDBKey() {
 911                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 912                         return $this->mUserCaseDBKey;
 913                 } else {
 914                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 915                         return $this->mDbkeyform;
 916                 }
 917         }
 918
 919         /**
 920          * Get the namespace index, i.e. one of the NS_xxxx constants.
 921          *
 922          * @return int Namespace index
 923          */
 924         public function getNamespace() {
 925                 return $this->mNamespace;
 926         }
 927
 928         /**
 929          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 930          *
 931          * @throws MWException
 932          * @return string Content model id
 933          */
 934         public function getContentModel() {
 935                 if ( !$this->mContentModel ) {
 936                         $linkCache = LinkCache::singleton();
 937                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 938                 }
 939
 940                 if ( !$this->mContentModel ) {
 941                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 942                 }
 943
 944                 if ( !$this->mContentModel ) {
 945                         throw new MWException( 'Failed to determine content model!' );
 946                 }
 947
 948                 return $this->mContentModel;
 949         }
 950
 951         /**
 952          * Convenience method for checking a title's content model name
 953          *
 954          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 955          * @return bool True if $this->getContentModel() == $id
 956          */
 957         public function hasContentModel( $id ) {
 958                 return $this->getContentModel() == $id;
 959         }
 960
 961         /**
 962          * Get the namespace text
 963          *
 964          * @return string Namespace text
 965          */
 966         public function getNsText() {
 967                 if ( $this->isExternal() ) {
 968                         // This probably shouldn't even happen. ohh man, oh yuck.
 969                         // But for interwiki transclusion it sometimes does.
 970                         // Shit. Shit shit shit.
 971                         //
 972                         // Use the canonical namespaces if possible to try to
 973                         // resolve a foreign namespace.
 974                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 975                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 976                         }
 977                 }
 978
 979                 try {
 980                         $formatter = $this->getTitleFormatter();
 981                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 982                 } catch ( InvalidArgumentException $ex )  {
 983                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 984                         return false;
 985                 }
 986         }
 987
 988         /**
 989          * Get the namespace text of the subject (rather than talk) page
 990          *
 991          * @return string Namespace text
 992          */
 993         public function getSubjectNsText() {
 994                 global $wgContLang;
 995                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 996         }
 997
 998         /**
 999          * Get the namespace text of the talk page
1000          *
1001          * @return string Namespace text
1002          */
1003         public function getTalkNsText() {
1004                 global $wgContLang;
1005                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1006         }
1007
1008         /**
1009          * Could this title have a corresponding talk page?
1010          *
1011          * @return bool
1012          */
1013         public function canTalk() {
1014                 return MWNamespace::canTalk( $this->mNamespace );
1015         }
1016
1017         /**
1018          * Is this in a namespace that allows actual pages?
1019          *
1020          * @return bool
1021          * @internal note -- uses hardcoded namespace index instead of constants
1022          */
1023         public function canExist() {
1024                 return $this->mNamespace >= NS_MAIN;
1025         }
1026
1027         /**
1028          * Can this title be added to a user's watchlist?
1029          *
1030          * @return bool
1031          */
1032         public function isWatchable() {
1033                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1034         }
1035
1036         /**
1037          * Returns true if this is a special page.
1038          *
1039          * @return bool
1040          */
1041         public function isSpecialPage() {
1042                 return $this->getNamespace() == NS_SPECIAL;
1043         }
1044
1045         /**
1046          * Returns true if this title resolves to the named special page
1047          *
1048          * @param string $name The special page name
1049          * @return bool
1050          */
1051         public function isSpecial( $name ) {
1052                 if ( $this->isSpecialPage() ) {
1053                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1054                         if ( $name == $thisName ) {
1055                                 return true;
1056                         }
1057                 }
1058                 return false;
1059         }
1060
1061         /**
1062          * If the Title refers to a special page alias which is not the local default, resolve
1063          * the alias, and localise the name as necessary.  Otherwise, return $this
1064          *
1065          * @return Title
1066          */
1067         public function fixSpecialName() {
1068                 if ( $this->isSpecialPage() ) {
1069                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1070                         if ( $canonicalName ) {
1071                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1072                                 if ( $localName != $this->mDbkeyform ) {
1073                                         return Title::makeTitle( NS_SPECIAL, $localName );
1074                                 }
1075                         }
1076                 }
1077                 return $this;
1078         }
1079
1080         /**
1081          * Returns true if the title is inside the specified namespace.
1082          *
1083          * Please make use of this instead of comparing to getNamespace()
1084          * This function is much more resistant to changes we may make
1085          * to namespaces than code that makes direct comparisons.
1086          * @param int $ns The namespace
1087          * @return bool
1088          * @since 1.19
1089          */
1090         public function inNamespace( $ns ) {
1091                 return MWNamespace::equals( $this->getNamespace(), $ns );
1092         }
1093
1094         /**
1095          * Returns true if the title is inside one of the specified namespaces.
1096          *
1097          * @param ...$namespaces The namespaces to check for
1098          * @return bool
1099          * @since 1.19
1100          */
1101         public function inNamespaces( /* ... */ ) {
1102                 $namespaces = func_get_args();
1103                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1104                         $namespaces = $namespaces[0];
1105                 }
1106
1107                 foreach ( $namespaces as $ns ) {
1108                         if ( $this->inNamespace( $ns ) ) {
1109                                 return true;
1110                         }
1111                 }
1112
1113                 return false;
1114         }
1115
1116         /**
1117          * Returns true if the title has the same subject namespace as the
1118          * namespace specified.
1119          * For example this method will take NS_USER and return true if namespace
1120          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1121          * as their subject namespace.
1122          *
1123          * This is MUCH simpler than individually testing for equivalence
1124          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1125          * @since 1.19
1126          * @param int $ns
1127          * @return bool
1128          */
1129         public function hasSubjectNamespace( $ns ) {
1130                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1131         }
1132
1133         /**
1134          * Is this Title in a namespace which contains content?
1135          * In other words, is this a content page, for the purposes of calculating
1136          * statistics, etc?
1137          *
1138          * @return bool
1139          */
1140         public function isContentPage() {
1141                 return MWNamespace::isContent( $this->getNamespace() );
1142         }
1143
1144         /**
1145          * Would anybody with sufficient privileges be able to move this page?
1146          * Some pages just aren't movable.
1147          *
1148          * @return bool
1149          */
1150         public function isMovable() {
1151                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1152                         // Interwiki title or immovable namespace. Hooks don't get to override here
1153                         return false;
1154                 }
1155
1156                 $result = true;
1157                 wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
1158                 return $result;
1159         }
1160
1161         /**
1162          * Is this the mainpage?
1163          * @note Title::newFromText seems to be sufficiently optimized by the title
1164          * cache that we don't need to over-optimize by doing direct comparisons and
1165          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1166          * ends up reporting something differently than $title->isMainPage();
1167          *
1168          * @since 1.18
1169          * @return bool
1170          */
1171         public function isMainPage() {
1172                 return $this->equals( Title::newMainPage() );
1173         }
1174
1175         /**
1176          * Is this a subpage?
1177          *
1178          * @return bool
1179          */
1180         public function isSubpage() {
1181                 return MWNamespace::hasSubpages( $this->mNamespace )
1182                         ? strpos( $this->getText(), '/' ) !== false
1183                         : false;
1184         }
1185
1186         /**
1187          * Is this a conversion table for the LanguageConverter?
1188          *
1189          * @return bool
1190          */
1191         public function isConversionTable() {
1192                 // @todo ConversionTable should become a separate content model.
1193
1194                 return $this->getNamespace() == NS_MEDIAWIKI &&
1195                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1196         }
1197
1198         /**
1199          * Does that page contain wikitext, or it is JS, CSS or whatever?
1200          *
1201          * @return bool
1202          */
1203         public function isWikitextPage() {
1204                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1205         }
1206
1207         /**
1208          * Could this page contain custom CSS or JavaScript for the global UI.
1209          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1210          * or CONTENT_MODEL_JAVASCRIPT.
1211          *
1212          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1213          * for that!
1214          *
1215          * Note that this method should not return true for pages that contain and
1216          * show "inactive" CSS or JS.
1217          *
1218          * @return bool
1219          */
1220         public function isCssOrJsPage() {
1221                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1222                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1223                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1224
1225                 # @note This hook is also called in ContentHandler::getDefaultModel.
1226                 #   It's called here again to make sure hook functions can force this
1227                 #   method to return true even outside the mediawiki namespace.
1228
1229                 wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ) );
1230
1231                 return $isCssOrJsPage;
1232         }
1233
1234         /**
1235          * Is this a .css or .js subpage of a user page?
1236          * @return bool
1237          */
1238         public function isCssJsSubpage() {
1239                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1240                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1241                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1242         }
1243
1244         /**
1245          * Trim down a .css or .js subpage title to get the corresponding skin name
1246          *
1247          * @return string Containing skin name from .css or .js subpage title
1248          */
1249         public function getSkinFromCssJsSubpage() {
1250                 $subpage = explode( '/', $this->mTextform );
1251                 $subpage = $subpage[count( $subpage ) - 1];
1252                 $lastdot = strrpos( $subpage, '.' );
1253                 if ( $lastdot === false ) {
1254                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1255                 }
1256                 return substr( $subpage, 0, $lastdot );
1257         }
1258
1259         /**
1260          * Is this a .css subpage of a user page?
1261          *
1262          * @return bool
1263          */
1264         public function isCssSubpage() {
1265                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1266                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1267         }
1268
1269         /**
1270          * Is this a .js subpage of a user page?
1271          *
1272          * @return bool
1273          */
1274         public function isJsSubpage() {
1275                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1276                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1277         }
1278
1279         /**
1280          * Is this a talk page of some sort?
1281          *
1282          * @return bool
1283          */
1284         public function isTalkPage() {
1285                 return MWNamespace::isTalk( $this->getNamespace() );
1286         }
1287
1288         /**
1289          * Get a Title object associated with the talk page of this article
1290          *
1291          * @return Title The object for the talk page
1292          */
1293         public function getTalkPage() {
1294                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1295         }
1296
1297         /**
1298          * Get a title object associated with the subject page of this
1299          * talk page
1300          *
1301          * @return Title The object for the subject page
1302          */
1303         public function getSubjectPage() {
1304                 // Is this the same title?
1305                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1306                 if ( $this->getNamespace() == $subjectNS ) {
1307                         return $this;
1308                 }
1309                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1310         }
1311
1312         /**
1313          * Get the default namespace index, for when there is no namespace
1314          *
1315          * @return int Default namespace index
1316          */
1317         public function getDefaultNamespace() {
1318                 return $this->mDefaultNamespace;
1319         }
1320
1321         /**
1322          * Get the Title fragment (i.e.\ the bit after the #) in text form
1323          *
1324          * Use Title::hasFragment to check for a fragment
1325          *
1326          * @return string Title fragment
1327          */
1328         public function getFragment() {
1329                 return $this->mFragment;
1330         }
1331
1332         /**
1333          * Check if a Title fragment is set
1334          *
1335          * @return bool
1336          * @since 1.23
1337          */
1338         public function hasFragment() {
1339                 return $this->mFragment !== '';
1340         }
1341
1342         /**
1343          * Get the fragment in URL form, including the "#" character if there is one
1344          * @return string Fragment in URL form
1345          */
1346         public function getFragmentForURL() {
1347                 if ( !$this->hasFragment() ) {
1348                         return '';
1349                 } else {
1350                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1351                 }
1352         }
1353
1354         /**
1355          * Set the fragment for this title. Removes the first character from the
1356          * specified fragment before setting, so it assumes you're passing it with
1357          * an initial "#".
1358          *
1359          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1360          * Still in active use privately.
1361          *
1362          * @param string $fragment Text
1363          */
1364         public function setFragment( $fragment ) {
1365                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1366         }
1367
1368         /**
1369          * Prefix some arbitrary text with the namespace or interwiki prefix
1370          * of this object
1371          *
1372          * @param string $name The text
1373          * @return string The prefixed text
1374          * @private
1375          */
1376         private function prefix( $name ) {
1377                 $p = '';
1378                 if ( $this->isExternal() ) {
1379                         $p = $this->mInterwiki . ':';
1380                 }
1381
1382                 if ( 0 != $this->mNamespace ) {
1383                         $p .= $this->getNsText() . ':';
1384                 }
1385                 return $p . $name;
1386         }
1387
1388         /**
1389          * Get the prefixed database key form
1390          *
1391          * @return string The prefixed title, with underscores and
1392          *  any interwiki and namespace prefixes
1393          */
1394         public function getPrefixedDBkey() {
1395                 $s = $this->prefix( $this->mDbkeyform );
1396                 $s = str_replace( ' ', '_', $s );
1397                 return $s;
1398         }
1399
1400         /**
1401          * Get the prefixed title with spaces.
1402          * This is the form usually used for display
1403          *
1404          * @return string The prefixed title, with spaces
1405          */
1406         public function getPrefixedText() {
1407                 if ( $this->mPrefixedText === null ) {
1408                         $s = $this->prefix( $this->mTextform );
1409                         $s = str_replace( '_', ' ', $s );
1410                         $this->mPrefixedText = $s;
1411                 }
1412                 return $this->mPrefixedText;
1413         }
1414
1415         /**
1416          * Return a string representation of this title
1417          *
1418          * @return string Representation of this title
1419          */
1420         public function __toString() {
1421                 return $this->getPrefixedText();
1422         }
1423
1424         /**
1425          * Get the prefixed title with spaces, plus any fragment
1426          * (part beginning with '#')
1427          *
1428          * @return string The prefixed title, with spaces and the fragment, including '#'
1429          */
1430         public function getFullText() {
1431                 $text = $this->getPrefixedText();
1432                 if ( $this->hasFragment() ) {
1433                         $text .= '#' . $this->getFragment();
1434                 }
1435                 return $text;
1436         }
1437
1438         /**
1439          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1440          *
1441          * @par Example:
1442          * @code
1443          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1444          * # returns: 'Foo'
1445          * @endcode
1446          *
1447          * @return string Root name
1448          * @since 1.20
1449          */
1450         public function getRootText() {
1451                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1452                         return $this->getText();
1453                 }
1454
1455                 return strtok( $this->getText(), '/' );
1456         }
1457
1458         /**
1459          * Get the root page name title, i.e. the leftmost part before any slashes
1460          *
1461          * @par Example:
1462          * @code
1463          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1464          * # returns: Title{User:Foo}
1465          * @endcode
1466          *
1467          * @return Title Root title
1468          * @since 1.20
1469          */
1470         public function getRootTitle() {
1471                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1472         }
1473
1474         /**
1475          * Get the base page name without a namespace, i.e. the part before the subpage name
1476          *
1477          * @par Example:
1478          * @code
1479          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1480          * # returns: 'Foo/Bar'
1481          * @endcode
1482          *
1483          * @return string Base name
1484          */
1485         public function getBaseText() {
1486                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1487                         return $this->getText();
1488                 }
1489
1490                 $parts = explode( '/', $this->getText() );
1491                 # Don't discard the real title if there's no subpage involved
1492                 if ( count( $parts ) > 1 ) {
1493                         unset( $parts[count( $parts ) - 1] );
1494                 }
1495                 return implode( '/', $parts );
1496         }
1497
1498         /**
1499          * Get the base page name title, i.e. the part before the subpage name
1500          *
1501          * @par Example:
1502          * @code
1503          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1504          * # returns: Title{User:Foo/Bar}
1505          * @endcode
1506          *
1507          * @return Title Base title
1508          * @since 1.20
1509          */
1510         public function getBaseTitle() {
1511                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1512         }
1513
1514         /**
1515          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1516          *
1517          * @par Example:
1518          * @code
1519          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1520          * # returns: "Baz"
1521          * @endcode
1522          *
1523          * @return string Subpage name
1524          */
1525         public function getSubpageText() {
1526                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1527                         return $this->mTextform;
1528                 }
1529                 $parts = explode( '/', $this->mTextform );
1530                 return $parts[count( $parts ) - 1];
1531         }
1532
1533         /**
1534          * Get the title for a subpage of the current page
1535          *
1536          * @par Example:
1537          * @code
1538          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1539          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1540          * @endcode
1541          *
1542          * @param string $text The subpage name to add to the title
1543          * @return Title Subpage title
1544          * @since 1.20
1545          */
1546         public function getSubpage( $text ) {
1547                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1548         }
1549
1550         /**
1551          * Get the HTML-escaped displayable text form.
1552          * Used for the title field in <a> tags.
1553          *
1554          * @return string The text, including any prefixes
1555          * @deprecated since 1.19
1556          */
1557         public function getEscapedText() {
1558                 wfDeprecated( __METHOD__, '1.19' );
1559                 return htmlspecialchars( $this->getPrefixedText() );
1560         }
1561
1562         /**
1563          * Get a URL-encoded form of the subpage text
1564          *
1565          * @return string URL-encoded subpage name
1566          */
1567         public function getSubpageUrlForm() {
1568                 $text = $this->getSubpageText();
1569                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1570                 return $text;
1571         }
1572
1573         /**
1574          * Get a URL-encoded title (not an actual URL) including interwiki
1575          *
1576          * @return string The URL-encoded form
1577          */
1578         public function getPrefixedURL() {
1579                 $s = $this->prefix( $this->mDbkeyform );
1580                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1581                 return $s;
1582         }
1583
1584         /**
1585          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1586          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1587          * second argument named variant. This was deprecated in favor
1588          * of passing an array of option with a "variant" key
1589          * Once $query2 is removed for good, this helper can be dropped
1590          * and the wfArrayToCgi moved to getLocalURL();
1591          *
1592          * @since 1.19 (r105919)
1593          * @param array|string $query
1594          * @param bool $query2
1595          * @return string
1596          */
1597         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1598                 if ( $query2 !== false ) {
1599                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1600                                 "method called with a second parameter is deprecated. Add your " .
1601                                 "parameter to an array passed as the first parameter.", "1.19" );
1602                 }
1603                 if ( is_array( $query ) ) {
1604                         $query = wfArrayToCgi( $query );
1605                 }
1606                 if ( $query2 ) {
1607                         if ( is_string( $query2 ) ) {
1608                                 // $query2 is a string, we will consider this to be
1609                                 // a deprecated $variant argument and add it to the query
1610                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1611                         } else {
1612                                 $query2 = wfArrayToCgi( $query2 );
1613                         }
1614                         // If we have $query content add a & to it first
1615                         if ( $query ) {
1616                                 $query .= '&';
1617                         }
1618                         // Now append the queries together
1619                         $query .= $query2;
1620                 }
1621                 return $query;
1622         }
1623
1624         /**
1625          * Get a real URL referring to this title, with interwiki link and
1626          * fragment
1627          *
1628          * @see self::getLocalURL for the arguments.
1629          * @see wfExpandUrl
1630          * @param array|string $query
1631          * @param bool $query2
1632          * @param string $proto Protocol type to use in URL
1633          * @return string The URL
1634          */
1635         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1636                 $query = self::fixUrlQueryArgs( $query, $query2 );
1637
1638                 # Hand off all the decisions on urls to getLocalURL
1639                 $url = $this->getLocalURL( $query );
1640
1641                 # Expand the url to make it a full url. Note that getLocalURL has the
1642                 # potential to output full urls for a variety of reasons, so we use
1643                 # wfExpandUrl instead of simply prepending $wgServer
1644                 $url = wfExpandUrl( $url, $proto );
1645
1646                 # Finally, add the fragment.
1647                 $url .= $this->getFragmentForURL();
1648
1649                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1650                 return $url;
1651         }
1652
1653         /**
1654          * Get a URL with no fragment or server name (relative URL) from a Title object.
1655          * If this page is generated with action=render, however,
1656          * $wgServer is prepended to make an absolute URL.
1657          *
1658          * @see self::getFullURL to always get an absolute URL.
1659          * @see self::newFromText to produce a Title object.
1660          *
1661          * @param string|array $query an optional query string,
1662          *   not used for interwiki links. Can be specified as an associative array as well,
1663          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1664          *   Some query patterns will trigger various shorturl path replacements.
1665          * @param array $query2 An optional secondary query array. This one MUST
1666          *   be an array. If a string is passed it will be interpreted as a deprecated
1667          *   variant argument and urlencoded into a variant= argument.
1668          *   This second query argument will be added to the $query
1669          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1670          *   pair in the first parameter array instead.
1671          *
1672          * @return string String of the URL.
1673          */
1674         public function getLocalURL( $query = '', $query2 = false ) {
1675                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1676
1677                 $query = self::fixUrlQueryArgs( $query, $query2 );
1678
1679                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1680                 if ( $interwiki ) {
1681                         $namespace = $this->getNsText();
1682                         if ( $namespace != '' ) {
1683                                 # Can this actually happen? Interwikis shouldn't be parsed.
1684                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1685                                 $namespace .= ':';
1686                         }
1687                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1688                         $url = wfAppendQuery( $url, $query );
1689                 } else {
1690                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1691                         if ( $query == '' ) {
1692                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1693                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1694                         } else {
1695                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1696                                 $url = false;
1697                                 $matches = array();
1698
1699                                 if ( !empty( $wgActionPaths )
1700                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1701                                 ) {
1702                                         $action = urldecode( $matches[2] );
1703                                         if ( isset( $wgActionPaths[$action] ) ) {
1704                                                 $query = $matches[1];
1705                                                 if ( isset( $matches[4] ) ) {
1706                                                         $query .= $matches[4];
1707                                                 }
1708                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1709                                                 if ( $query != '' ) {
1710                                                         $url = wfAppendQuery( $url, $query );
1711                                                 }
1712                                         }
1713                                 }
1714
1715                                 if ( $url === false
1716                                         && $wgVariantArticlePath
1717                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1718                                         && $this->getPageLanguage()->hasVariants()
1719                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1720                                 ) {
1721                                         $variant = urldecode( $matches[1] );
1722                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1723                                                 // Only do the variant replacement if the given variant is a valid
1724                                                 // variant for the page's language.
1725                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1726                                                 $url = str_replace( '$1', $dbkey, $url );
1727                                         }
1728                                 }
1729
1730                                 if ( $url === false ) {
1731                                         if ( $query == '-' ) {
1732                                                 $query = '';
1733                                         }
1734                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1735                                 }
1736                         }
1737
1738                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1739
1740                         // @todo FIXME: This causes breakage in various places when we
1741                         // actually expected a local URL and end up with dupe prefixes.
1742                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1743                                 $url = $wgServer . $url;
1744                         }
1745                 }
1746                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1747                 return $url;
1748         }
1749
1750         /**
1751          * Get a URL that's the simplest URL that will be valid to link, locally,
1752          * to the current Title.  It includes the fragment, but does not include
1753          * the server unless action=render is used (or the link is external).  If
1754          * there's a fragment but the prefixed text is empty, we just return a link
1755          * to the fragment.
1756          *
1757          * The result obviously should not be URL-escaped, but does need to be
1758          * HTML-escaped if it's being output in HTML.
1759          *
1760          * @param array $query
1761          * @param bool $query2
1762          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1763          * @see self::getLocalURL for the arguments.
1764          * @return string The URL
1765          */
1766         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1767                 wfProfileIn( __METHOD__ );
1768                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1769                         $ret = $this->getFullURL( $query, $query2, $proto );
1770                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1771                         $ret = $this->getFragmentForURL();
1772                 } else {
1773                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1774                 }
1775                 wfProfileOut( __METHOD__ );
1776                 return $ret;
1777         }
1778
1779         /**
1780          * Get an HTML-escaped version of the URL form, suitable for
1781          * using in a link, without a server name or fragment
1782          *
1783          * @see self::getLocalURL for the arguments.
1784          * @param string $query
1785          * @param bool|string $query2
1786          * @return string The URL
1787          * @deprecated since 1.19
1788          */
1789         public function escapeLocalURL( $query = '', $query2 = false ) {
1790                 wfDeprecated( __METHOD__, '1.19' );
1791                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1792         }
1793
1794         /**
1795          * Get an HTML-escaped version of the URL form, suitable for
1796          * using in a link, including the server name and fragment
1797          *
1798          * @see self::getLocalURL for the arguments.
1799          * @return string The URL
1800          * @deprecated since 1.19
1801          */
1802         public function escapeFullURL( $query = '', $query2 = false ) {
1803                 wfDeprecated( __METHOD__, '1.19' );
1804                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1805         }
1806
1807         /**
1808          * Get the URL form for an internal link.
1809          * - Used in various Squid-related code, in case we have a different
1810          * internal hostname for the server from the exposed one.
1811          *
1812          * This uses $wgInternalServer to qualify the path, or $wgServer
1813          * if $wgInternalServer is not set. If the server variable used is
1814          * protocol-relative, the URL will be expanded to http://
1815          *
1816          * @see self::getLocalURL for the arguments.
1817          * @return string The URL
1818          */
1819         public function getInternalURL( $query = '', $query2 = false ) {
1820                 global $wgInternalServer, $wgServer;
1821                 $query = self::fixUrlQueryArgs( $query, $query2 );
1822                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1823                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1824                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1825                 return $url;
1826         }
1827
1828         /**
1829          * Get the URL for a canonical link, for use in things like IRC and
1830          * e-mail notifications. Uses $wgCanonicalServer and the
1831          * GetCanonicalURL hook.
1832          *
1833          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1834          *
1835          * @see self::getLocalURL for the arguments.
1836          * @return string The URL
1837          * @since 1.18
1838          */
1839         public function getCanonicalURL( $query = '', $query2 = false ) {
1840                 $query = self::fixUrlQueryArgs( $query, $query2 );
1841                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1842                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1843                 return $url;
1844         }
1845
1846         /**
1847          * HTML-escaped version of getCanonicalURL()
1848          *
1849          * @see self::getLocalURL for the arguments.
1850          * @since 1.18
1851          * @return string
1852          * @deprecated since 1.19
1853          */
1854         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1855                 wfDeprecated( __METHOD__, '1.19' );
1856                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1857         }
1858
1859         /**
1860          * Get the edit URL for this Title
1861          *
1862          * @return string The URL, or a null string if this is an interwiki link
1863          */
1864         public function getEditURL() {
1865                 if ( $this->isExternal() ) {
1866                         return '';
1867                 }
1868                 $s = $this->getLocalURL( 'action=edit' );
1869
1870                 return $s;
1871         }
1872
1873         /**
1874          * Is $wgUser watching this page?
1875          *
1876          * @deprecated since 1.20; use User::isWatched() instead.
1877          * @return bool
1878          */
1879         public function userIsWatching() {
1880                 global $wgUser;
1881
1882                 if ( is_null( $this->mWatched ) ) {
1883                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1884                                 $this->mWatched = false;
1885                         } else {
1886                                 $this->mWatched = $wgUser->isWatched( $this );
1887                         }
1888                 }
1889                 return $this->mWatched;
1890         }
1891
1892         /**
1893          * Can $wgUser read this page?
1894          *
1895          * @deprecated since 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1896          * @return bool
1897          */
1898         public function userCanRead() {
1899                 wfDeprecated( __METHOD__, '1.19' );
1900                 return $this->userCan( 'read' );
1901         }
1902
1903         /**
1904          * Can $user perform $action on this page?
1905          * This skips potentially expensive cascading permission checks
1906          * as well as avoids expensive error formatting
1907          *
1908          * Suitable for use for nonessential UI controls in common cases, but
1909          * _not_ for functional access control.
1910          *
1911          * May provide false positives, but should never provide a false negative.
1912          *
1913          * @param string $action Action that permission needs to be checked for
1914          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1915          * @return bool
1916          */
1917         public function quickUserCan( $action, $user = null ) {
1918                 return $this->userCan( $action, $user, false );
1919         }
1920
1921         /**
1922          * Can $user perform $action on this page?
1923          *
1924          * @param string $action Action that permission needs to be checked for
1925          * @param User $user User to check (since 1.19); $wgUser will be used if not
1926          *   provided.
1927          * @param bool $doExpensiveQueries Set this to false to avoid doing
1928          *   unnecessary queries.
1929          * @return bool
1930          */
1931         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1932                 if ( !$user instanceof User ) {
1933                         global $wgUser;
1934                         $user = $wgUser;
1935                 }
1936
1937                 return !count( $this->getUserPermissionsErrorsInternal(
1938                         $action, $user, $doExpensiveQueries, true ) );
1939         }
1940
1941         /**
1942          * Can $user perform $action on this page?
1943          *
1944          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1945          *
1946          * @param string $action action that permission needs to be checked for
1947          * @param User $user User to check
1948          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1949          *   queries by skipping checks for cascading protections and user blocks.
1950          * @param array $ignoreErrors of Strings Set this to a list of message keys
1951          *   whose corresponding errors may be ignored.
1952          * @return array Array of arguments to wfMessage to explain permissions problems.
1953          */
1954         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true,
1955                 $ignoreErrors = array()
1956         ) {
1957                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1958
1959                 // Remove the errors being ignored.
1960                 foreach ( $errors as $index => $error ) {
1961                         $error_key = is_array( $error ) ? $error[0] : $error;
1962
1963                         if ( in_array( $error_key, $ignoreErrors ) ) {
1964                                 unset( $errors[$index] );
1965                         }
1966                 }
1967
1968                 return $errors;
1969         }
1970
1971         /**
1972          * Permissions checks that fail most often, and which are easiest to test.
1973          *
1974          * @param string $action the action to check
1975          * @param User $user User to check
1976          * @param array $errors List of current errors
1977          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
1978          * @param bool $short Short circuit on first error
1979          *
1980          * @return array List of errors
1981          */
1982         private function checkQuickPermissions( $action, $user, $errors,
1983                 $doExpensiveQueries, $short
1984         ) {
1985                 if ( !wfRunHooks( 'TitleQuickPermissions',
1986                         array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) )
1987                 ) {
1988                         return $errors;
1989                 }
1990
1991                 if ( $action == 'create' ) {
1992                         if (
1993                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1994                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1995                         ) {
1996                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1997                         }
1998                 } elseif ( $action == 'move' ) {
1999                         if ( !$user->isAllowed( 'move-rootuserpages' )
2000                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2001                                 // Show user page-specific message only if the user can move other pages
2002                                 $errors[] = array( 'cant-move-user-page' );
2003                         }
2004
2005                         // Check if user is allowed to move files if it's a file
2006                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2007                                 $errors[] = array( 'movenotallowedfile' );
2008                         }
2009
2010                         // Check if user is allowed to move category pages if it's a category page
2011                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2012                                 $errors[] = array( 'cant-move-category-page' );
2013                         }
2014
2015                         if ( !$user->isAllowed( 'move' ) ) {
2016                                 // User can't move anything
2017                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2018                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2019                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2020                                         // custom message if logged-in users without any special rights can move
2021                                         $errors[] = array( 'movenologintext' );
2022                                 } else {
2023                                         $errors[] = array( 'movenotallowed' );
2024                                 }
2025                         }
2026                 } elseif ( $action == 'move-target' ) {
2027                         if ( !$user->isAllowed( 'move' ) ) {
2028                                 // User can't move anything
2029                                 $errors[] = array( 'movenotallowed' );
2030                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2031                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2032                                 // Show user page-specific message only if the user can move other pages
2033                                 $errors[] = array( 'cant-move-to-user-page' );
2034                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2035                                         && $this->mNamespace == NS_CATEGORY ) {
2036                                 // Show category page-specific message only if the user can move other pages
2037                                 $errors[] = array( 'cant-move-to-category-page' );
2038                         }
2039                 } elseif ( !$user->isAllowed( $action ) ) {
2040                         $errors[] = $this->missingPermissionError( $action, $short );
2041                 }
2042
2043                 return $errors;
2044         }
2045
2046         /**
2047          * Add the resulting error code to the errors array
2048          *
2049          * @param array $errors List of current errors
2050          * @param array $result Result of errors
2051          *
2052          * @return array List of errors
2053          */
2054         private function resultToError( $errors, $result ) {
2055                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2056                         // A single array representing an error
2057                         $errors[] = $result;
2058                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2059                         // A nested array representing multiple errors
2060                         $errors = array_merge( $errors, $result );
2061                 } elseif ( $result !== '' && is_string( $result ) ) {
2062                         // A string representing a message-id
2063                         $errors[] = array( $result );
2064                 } elseif ( $result === false ) {
2065                         // a generic "We don't want them to do that"
2066                         $errors[] = array( 'badaccess-group0' );
2067                 }
2068                 return $errors;
2069         }
2070
2071         /**
2072          * Check various permission hooks
2073          *
2074          * @param string $action The action to check
2075          * @param User $user User to check
2076          * @param array $errors List of current errors
2077          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2078          * @param bool $short Short circuit on first error
2079          *
2080          * @return array List of errors
2081          */
2082         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
2083                 // Use getUserPermissionsErrors instead
2084                 $result = '';
2085                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2086                         return $result ? array() : array( array( 'badaccess-group0' ) );
2087                 }
2088                 // Check getUserPermissionsErrors hook
2089                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2090                         $errors = $this->resultToError( $errors, $result );
2091                 }
2092                 // Check getUserPermissionsErrorsExpensive hook
2093                 if (
2094                         $doExpensiveQueries
2095                         && !( $short && count( $errors ) > 0 )
2096                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2097                 ) {
2098                         $errors = $this->resultToError( $errors, $result );
2099                 }
2100
2101                 return $errors;
2102         }
2103
2104         /**
2105          * Check permissions on special pages & namespaces
2106          *
2107          * @param string $action The action to check
2108          * @param User $user User to check
2109          * @param array $errors List of current errors
2110          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2111          * @param bool $short Short circuit on first error
2112          *
2113          * @return array List of errors
2114          */
2115         private function checkSpecialsAndNSPermissions( $action, $user, $errors,
2116                 $doExpensiveQueries, $short
2117         ) {
2118                 # Only 'createaccount' can be performed on special pages,
2119                 # which don't actually exist in the DB.
2120                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2121                         $errors[] = array( 'ns-specialprotected' );
2122                 }
2123
2124                 # Check $wgNamespaceProtection for restricted namespaces
2125                 if ( $this->isNamespaceProtected( $user ) ) {
2126                         $ns = $this->mNamespace == NS_MAIN ?
2127                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2128                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2129                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
2130                 }
2131
2132                 return $errors;
2133         }
2134
2135         /**
2136          * Check CSS/JS sub-page permissions
2137          *
2138          * @param string $action The action to check
2139          * @param User $user User to check
2140          * @param array $errors List of current errors
2141          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2142          * @param bool $short Short circuit on first error
2143          *
2144          * @return array List of errors
2145          */
2146         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2147                 # Protect css/js subpages of user pages
2148                 # XXX: this might be better using restrictions
2149                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2150                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2151                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2152                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2153                                         $errors[] = array( 'mycustomcssprotected' );
2154                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2155                                         $errors[] = array( 'mycustomjsprotected' );
2156                                 }
2157                         } else {
2158                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2159                                         $errors[] = array( 'customcssprotected' );
2160                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2161                                         $errors[] = array( 'customjsprotected' );
2162                                 }
2163                         }
2164                 }
2165
2166                 return $errors;
2167         }
2168
2169         /**
2170          * Check against page_restrictions table requirements on this
2171          * page. The user must possess all required rights for this
2172          * action.
2173          *
2174          * @param string $action The action to check
2175          * @param User $user User to check
2176          * @param array $errors List of current errors
2177          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2178          * @param bool $short Short circuit on first error
2179          *
2180          * @return array List of errors
2181          */
2182         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2183                 foreach ( $this->getRestrictions( $action ) as $right ) {
2184                         // Backwards compatibility, rewrite sysop -> editprotected
2185                         if ( $right == 'sysop' ) {
2186                                 $right = 'editprotected';
2187                         }
2188                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2189                         if ( $right == 'autoconfirmed' ) {
2190                                 $right = 'editsemiprotected';
2191                         }
2192                         if ( $right == '' ) {
2193                                 continue;
2194                         }
2195                         if ( !$user->isAllowed( $right ) ) {
2196                                 $errors[] = array( 'protectedpagetext', $right );
2197                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2198                                 $errors[] = array( 'protectedpagetext', 'protect' );
2199                         }
2200                 }
2201
2202                 return $errors;
2203         }
2204
2205         /**
2206          * Check restrictions on cascading pages.
2207          *
2208          * @param string $action The action to check
2209          * @param User $user User to check
2210          * @param array $errors List of current errors
2211          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2212          * @param bool $short Short circuit on first error
2213          *
2214          * @return array List of errors
2215          */
2216         private function checkCascadingSourcesRestrictions( $action, $user, $errors,
2217                 $doExpensiveQueries, $short
2218         ) {
2219                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2220                         # We /could/ use the protection level on the source page, but it's
2221                         # fairly ugly as we have to establish a precedence hierarchy for pages
2222                         # included by multiple cascade-protected pages. So just restrict
2223                         # it to people with 'protect' permission, as they could remove the
2224                         # protection anyway.
2225                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2226                         # Cascading protection depends on more than this page...
2227                         # Several cascading protected pages may include this page...
2228                         # Check each cascading level
2229                         # This is only for protection restrictions, not for all actions
2230                         if ( isset( $restrictions[$action] ) ) {
2231                                 foreach ( $restrictions[$action] as $right ) {
2232                                         // Backwards compatibility, rewrite sysop -> editprotected
2233                                         if ( $right == 'sysop' ) {
2234                                                 $right = 'editprotected';
2235                                         }
2236                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2237                                         if ( $right == 'autoconfirmed' ) {
2238                                                 $right = 'editsemiprotected';
2239                                         }
2240                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2241                                                 $pages = '';
2242                                                 foreach ( $cascadingSources as $page ) {
2243                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2244                                                 }
2245                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2246                                         }
2247                                 }
2248                         }
2249                 }
2250
2251                 return $errors;
2252         }
2253
2254         /**
2255          * Check action permissions not already checked in checkQuickPermissions
2256          *
2257          * @param string $action The action to check
2258          * @param User $user User to check
2259          * @param array $errors List of current errors
2260          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2261          * @param bool $short Short circuit on first error
2262          *
2263          * @return array List of errors
2264          */
2265         private function checkActionPermissions( $action, $user, $errors,
2266                 $doExpensiveQueries, $short
2267         ) {
2268                 global $wgDeleteRevisionsLimit, $wgLang;
2269
2270                 if ( $action == 'protect' ) {
2271                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit',
2272                                 $user, $doExpensiveQueries, true ) )
2273                         ) {
2274                                 // If they can't edit, they shouldn't protect.
2275                                 $errors[] = array( 'protect-cantedit' );
2276                         }
2277                 } elseif ( $action == 'create' ) {
2278                         $title_protection = $this->getTitleProtection();
2279                         if ( $title_protection ) {
2280                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2281                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2282                                 }
2283                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2284                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2285                                 }
2286                                 if ( $title_protection['pt_create_perm'] == ''
2287                                         || !$user->isAllowed( $title_protection['pt_create_perm'] )
2288                                 ) {
2289                                         $errors[] = array(
2290                                                 'titleprotected',
2291                                                 User::whoIs( $title_protection['pt_user'] ),
2292                                                 $title_protection['pt_reason']
2293                                         );
2294                                 }
2295                         }
2296                 } elseif ( $action == 'move' ) {
2297                         // Check for immobile pages
2298                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2299                                 // Specific message for this case
2300                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2301                         } elseif ( !$this->isMovable() ) {
2302                                 // Less specific message for rarer cases
2303                                 $errors[] = array( 'immobile-source-page' );
2304                         }
2305                 } elseif ( $action == 'move-target' ) {
2306                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2307                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2308                         } elseif ( !$this->isMovable() ) {
2309                                 $errors[] = array( 'immobile-target-page' );
2310                         }
2311                 } elseif ( $action == 'delete' ) {
2312                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2313                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2314                         ) {
2315                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2316                         }
2317                 }
2318                 return $errors;
2319         }
2320
2321         /**
2322          * Check that the user isn't blocked from editing.
2323          *
2324          * @param string $action The action to check
2325          * @param User $user User to check
2326          * @param array $errors List of current errors
2327          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2328          * @param bool $short Short circuit on first error
2329          *
2330          * @return array List of errors
2331          */
2332         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2333                 // Account creation blocks handled at userlogin.
2334                 // Unblocking handled in SpecialUnblock
2335                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2336                         return $errors;
2337                 }
2338
2339                 global $wgEmailConfirmToEdit;
2340
2341                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2342                         $errors[] = array( 'confirmedittext' );
2343                 }
2344
2345                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2346                         // Don't block the user from editing their own talk page unless they've been
2347                         // explicitly blocked from that too.
2348                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2349                         // @todo FIXME: Pass the relevant context into this function.
2350                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2351                 }
2352
2353                 return $errors;
2354         }
2355
2356         /**
2357          * Check that the user is allowed to read this page.
2358          *
2359          * @param string $action The action to check
2360          * @param User $user User to check
2361          * @param array $errors List of current errors
2362          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2363          * @param bool $short Short circuit on first error
2364          *
2365          * @return array List of errors
2366          */
2367         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2368                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2369
2370                 $whitelisted = false;
2371                 if ( User::isEveryoneAllowed( 'read' ) ) {
2372                         # Shortcut for public wikis, allows skipping quite a bit of code
2373                         $whitelisted = true;
2374                 } elseif ( $user->isAllowed( 'read' ) ) {
2375                         # If the user is allowed to read pages, he is allowed to read all pages
2376                         $whitelisted = true;
2377                 } elseif ( $this->isSpecial( 'Userlogin' )
2378                         || $this->isSpecial( 'ChangePassword' )
2379                         || $this->isSpecial( 'PasswordReset' )
2380                 ) {
2381                         # Always grant access to the login page.
2382                         # Even anons need to be able to log in.
2383                         $whitelisted = true;
2384                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2385                         # Time to check the whitelist
2386                         # Only do these checks is there's something to check against
2387                         $name = $this->getPrefixedText();
2388                         $dbName = $this->getPrefixedDBkey();
2389
2390                         // Check for explicit whitelisting with and without underscores
2391                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2392                                 $whitelisted = true;
2393                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2394                                 # Old settings might have the title prefixed with
2395                                 # a colon for main-namespace pages
2396                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2397                                         $whitelisted = true;
2398                                 }
2399                         } elseif ( $this->isSpecialPage() ) {
2400                                 # If it's a special page, ditch the subpage bit and check again
2401                                 $name = $this->getDBkey();
2402                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2403                                 if ( $name ) {
2404                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2405                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2406                                                 $whitelisted = true;
2407                                         }
2408                                 }
2409                         }
2410                 }
2411
2412                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2413                         $name = $this->getPrefixedText();
2414                         // Check for regex whitelisting
2415                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2416                                 if ( preg_match( $listItem, $name ) ) {
2417                                         $whitelisted = true;
2418                                         break;
2419                                 }
2420                         }
2421                 }
2422
2423                 if ( !$whitelisted ) {
2424                         # If the title is not whitelisted, give extensions a chance to do so...
2425                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2426                         if ( !$whitelisted ) {
2427                                 $errors[] = $this->missingPermissionError( $action, $short );
2428                         }
2429                 }
2430
2431                 return $errors;
2432         }
2433
2434         /**
2435          * Get a description array when the user doesn't have the right to perform
2436          * $action (i.e. when User::isAllowed() returns false)
2437          *
2438          * @param string $action The action to check
2439          * @param bool $short Short circuit on first error
2440          * @return array List of errors
2441          */
2442         private function missingPermissionError( $action, $short ) {
2443                 // We avoid expensive display logic for quickUserCan's and such
2444                 if ( $short ) {
2445                         return array( 'badaccess-group0' );
2446                 }
2447
2448                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2449                         User::getGroupsWithPermission( $action ) );
2450
2451                 if ( count( $groups ) ) {
2452                         global $wgLang;
2453                         return array(
2454                                 'badaccess-groups',
2455                                 $wgLang->commaList( $groups ),
2456                                 count( $groups )
2457                         );
2458                 } else {
2459                         return array( 'badaccess-group0' );
2460                 }
2461         }
2462
2463         /**
2464          * Can $user perform $action on this page? This is an internal function,
2465          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2466          * checks on wfReadOnly() and blocks)
2467          *
2468          * @param string $action Action that permission needs to be checked for
2469          * @param User $user User to check
2470          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2471          * @param bool $short Set this to true to stop after the first permission error.
2472          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2473          */
2474         protected function getUserPermissionsErrorsInternal( $action, $user,
2475                 $doExpensiveQueries = true, $short = false
2476         ) {
2477                 wfProfileIn( __METHOD__ );
2478
2479                 # Read has special handling
2480                 if ( $action == 'read' ) {
2481                         $checks = array(
2482                                 'checkPermissionHooks',
2483                                 'checkReadPermissions',
2484                         );
2485                 } else {
2486                         $checks = array(
2487                                 'checkQuickPermissions',
2488                                 'checkPermissionHooks',
2489                                 'checkSpecialsAndNSPermissions',
2490                                 'checkCSSandJSPermissions',
2491                                 'checkPageRestrictions',
2492                                 'checkCascadingSourcesRestrictions',
2493                                 'checkActionPermissions',
2494                                 'checkUserBlock'
2495                         );
2496                 }
2497
2498                 $errors = array();
2499                 while ( count( $checks ) > 0 &&
2500                                 !( $short && count( $errors ) > 0 ) ) {
2501                         $method = array_shift( $checks );
2502                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2503                 }
2504
2505                 wfProfileOut( __METHOD__ );
2506                 return $errors;
2507         }
2508
2509         /**
2510          * Get a filtered list of all restriction types supported by this wiki.
2511          * @param bool $exists True to get all restriction types that apply to
2512          * titles that do exist, False for all restriction types that apply to
2513          * titles that do not exist
2514          * @return array
2515          */
2516         public static function getFilteredRestrictionTypes( $exists = true ) {
2517                 global $wgRestrictionTypes;
2518                 $types = $wgRestrictionTypes;
2519                 if ( $exists ) {
2520                         # Remove the create restriction for existing titles
2521                         $types = array_diff( $types, array( 'create' ) );
2522                 } else {
2523                         # Only the create and upload restrictions apply to non-existing titles
2524                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2525                 }
2526                 return $types;
2527         }
2528
2529         /**
2530          * Returns restriction types for the current Title
2531          *
2532          * @return array Applicable restriction types
2533          */
2534         public function getRestrictionTypes() {
2535                 if ( $this->isSpecialPage() ) {
2536                         return array();
2537                 }
2538
2539                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2540
2541                 if ( $this->getNamespace() != NS_FILE ) {
2542                         # Remove the upload restriction for non-file titles
2543                         $types = array_diff( $types, array( 'upload' ) );
2544                 }
2545
2546                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2547
2548                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2549                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2550
2551                 return $types;
2552         }
2553
2554         /**
2555          * Is this title subject to title protection?
2556          * Title protection is the one applied against creation of such title.
2557          *
2558          * @return array|bool An associative array representing any existent title
2559          *   protection, or false if there's none.
2560          */
2561         private function getTitleProtection() {
2562                 // Can't protect pages in special namespaces
2563                 if ( $this->getNamespace() < 0 ) {
2564                         return false;
2565                 }
2566
2567                 // Can't protect pages that exist.
2568                 if ( $this->exists() ) {
2569                         return false;
2570                 }
2571
2572                 if ( $this->mTitleProtection === null ) {
2573                         $dbr = wfGetDB( DB_SLAVE );
2574                         $res = $dbr->select(
2575                                 'protected_titles',
2576                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2577                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2578                                 __METHOD__
2579                         );
2580
2581                         // fetchRow returns false if there are no rows.
2582                         $this->mTitleProtection = $dbr->fetchRow( $res );
2583                 }
2584                 return $this->mTitleProtection;
2585         }
2586
2587         /**
2588          * Update the title protection status
2589          *
2590          * @deprecated since 1.19; use WikiPage::doUpdateRestrictions() instead.
2591          * @param string $create_perm Permission required for creation
2592          * @param string $reason Reason for protection
2593          * @param string $expiry Expiry timestamp
2594          * @return bool
2595          */
2596         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2597                 wfDeprecated( __METHOD__, '1.19' );
2598
2599                 global $wgUser;
2600
2601                 $limit = array( 'create' => $create_perm );
2602                 $expiry = array( 'create' => $expiry );
2603
2604                 $page = WikiPage::factory( $this );
2605                 $cascade = false;
2606                 $status = $page->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $wgUser );
2607
2608                 return $status->isOK();
2609         }
2610
2611         /**
2612          * Remove any title protection due to page existing
2613          */
2614         public function deleteTitleProtection() {
2615                 $dbw = wfGetDB( DB_MASTER );
2616
2617                 $dbw->delete(
2618                         'protected_titles',
2619                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2620                         __METHOD__
2621                 );
2622                 $this->mTitleProtection = false;
2623         }
2624
2625         /**
2626          * Is this page "semi-protected" - the *only* protection levels are listed
2627          * in $wgSemiprotectedRestrictionLevels?
2628          *
2629          * @param string $action Action to check (default: edit)
2630          * @return bool
2631          */
2632         public function isSemiProtected( $action = 'edit' ) {
2633                 global $wgSemiprotectedRestrictionLevels;
2634
2635                 $restrictions = $this->getRestrictions( $action );
2636                 $semi = $wgSemiprotectedRestrictionLevels;
2637                 if ( !$restrictions || !$semi ) {
2638                         // Not protected, or all protection is full protection
2639                         return false;
2640                 }
2641
2642                 // Remap autoconfirmed to editsemiprotected for BC
2643                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2644                         $semi[$key] = 'editsemiprotected';
2645                 }
2646                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2647                         $restrictions[$key] = 'editsemiprotected';
2648                 }
2649
2650                 return !array_diff( $restrictions, $semi );
2651         }
2652
2653         /**
2654          * Does the title correspond to a protected article?
2655          *
2656          * @param string $action the action the page is protected from,
2657          * by default checks all actions.
2658          * @return bool
2659          */
2660         public function isProtected( $action = '' ) {
2661                 global $wgRestrictionLevels;
2662
2663                 $restrictionTypes = $this->getRestrictionTypes();
2664
2665                 # Special pages have inherent protection
2666                 if ( $this->isSpecialPage() ) {
2667                         return true;
2668                 }
2669
2670                 # Check regular protection levels
2671                 foreach ( $restrictionTypes as $type ) {
2672                         if ( $action == $type || $action == '' ) {
2673                                 $r = $this->getRestrictions( $type );
2674                                 foreach ( $wgRestrictionLevels as $level ) {
2675                                         if ( in_array( $level, $r ) && $level != '' ) {
2676                                                 return true;
2677                                         }
2678                                 }
2679                         }
2680                 }
2681
2682                 return false;
2683         }
2684
2685         /**
2686          * Determines if $user is unable to edit this page because it has been protected
2687          * by $wgNamespaceProtection.
2688          *
2689          * @param User $user User object to check permissions
2690          * @return bool
2691          */
2692         public function isNamespaceProtected( User $user ) {
2693                 global $wgNamespaceProtection;
2694
2695                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2696                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2697                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2698                                         return true;
2699                                 }
2700                         }
2701                 }
2702                 return false;
2703         }
2704
2705         /**
2706          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2707          *
2708          * @return bool If the page is subject to cascading restrictions.
2709          */
2710         public function isCascadeProtected() {
2711                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2712                 return ( $sources > 0 );
2713         }
2714
2715         /**
2716          * Determines whether cascading protection sources have already been loaded from
2717          * the database.
2718          *
2719          * @param bool $getPages True to check if the pages are loaded, or false to check
2720          * if the status is loaded.
2721          * @return bool Whether or not the specified information has been loaded
2722          * @since 1.23
2723          */
2724         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2725                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2726         }
2727
2728         /**
2729          * Cascading protection: Get the source of any cascading restrictions on this page.
2730          *
2731          * @param bool $getPages Whether or not to retrieve the actual pages
2732          *        that the restrictions have come from and the actual restrictions
2733          *        themselves.
2734          * @return array Two elements: First is an array of Title objects of the
2735          *        pages from which cascading restrictions have come, false for
2736          *        none, or true if such restrictions exist but $getPages was not
2737          *        set. Second is an array like that returned by
2738          *        Title::getAllRestrictions(), or an empty array if $getPages is
2739          *        false.
2740          */
2741         public function getCascadeProtectionSources( $getPages = true ) {
2742                 global $wgContLang;
2743                 $pagerestrictions = array();
2744
2745                 if ( $this->mCascadeSources !== null && $getPages ) {
2746                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2747                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2748                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2749                 }
2750
2751                 wfProfileIn( __METHOD__ );
2752
2753                 $dbr = wfGetDB( DB_SLAVE );
2754
2755                 if ( $this->getNamespace() == NS_FILE ) {
2756                         $tables = array( 'imagelinks', 'page_restrictions' );
2757                         $where_clauses = array(
2758                                 'il_to' => $this->getDBkey(),
2759                                 'il_from=pr_page',
2760                                 'pr_cascade' => 1
2761                         );
2762                 } else {
2763                         $tables = array( 'templatelinks', 'page_restrictions' );
2764                         $where_clauses = array(
2765                                 'tl_namespace' => $this->getNamespace(),
2766                                 'tl_title' => $this->getDBkey(),
2767                                 'tl_from=pr_page',
2768                                 'pr_cascade' => 1
2769                         );
2770                 }
2771
2772                 if ( $getPages ) {
2773                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2774                                 'pr_expiry', 'pr_type', 'pr_level' );
2775                         $where_clauses[] = 'page_id=pr_page';
2776                         $tables[] = 'page';
2777                 } else {
2778                         $cols = array( 'pr_expiry' );
2779                 }
2780
2781                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2782
2783                 $sources = $getPages ? array() : false;
2784                 $now = wfTimestampNow();
2785                 $purgeExpired = false;
2786
2787                 foreach ( $res as $row ) {
2788                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2789                         if ( $expiry > $now ) {
2790                                 if ( $getPages ) {
2791                                         $page_id = $row->pr_page;
2792                                         $page_ns = $row->page_namespace;
2793                                         $page_title = $row->page_title;
2794                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2795                                         # Add groups needed for each restriction type if its not already there
2796                                         # Make sure this restriction type still exists
2797
2798                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2799                                                 $pagerestrictions[$row->pr_type] = array();
2800                                         }
2801
2802                                         if (
2803                                                 isset( $pagerestrictions[$row->pr_type] )
2804                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2805                                         ) {
2806                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2807                                         }
2808                                 } else {
2809                                         $sources = true;
2810                                 }
2811                         } else {
2812                                 // Trigger lazy purge of expired restrictions from the db
2813                                 $purgeExpired = true;
2814                         }
2815                 }
2816                 if ( $purgeExpired ) {
2817                         Title::purgeExpiredRestrictions();
2818                 }
2819
2820                 if ( $getPages ) {
2821                         $this->mCascadeSources = $sources;
2822                         $this->mCascadingRestrictions = $pagerestrictions;
2823                 } else {
2824                         $this->mHasCascadingRestrictions = $sources;
2825                 }
2826
2827                 wfProfileOut( __METHOD__ );
2828                 return array( $sources, $pagerestrictions );
2829         }
2830
2831         /**
2832          * Accessor for mRestrictionsLoaded
2833          *
2834          * @return bool Whether or not the page's restrictions have already been
2835          * loaded from the database
2836          * @since 1.23
2837          */
2838         public function areRestrictionsLoaded() {
2839                 return $this->mRestrictionsLoaded;
2840         }
2841
2842         /**
2843          * Accessor/initialisation for mRestrictions
2844          *
2845          * @param string $action Action that permission needs to be checked for
2846          * @return array Restriction levels needed to take the action. All levels
2847          *     are required.
2848          */
2849         public function getRestrictions( $action ) {
2850                 if ( !$this->mRestrictionsLoaded ) {
2851                         $this->loadRestrictions();
2852                 }
2853                 return isset( $this->mRestrictions[$action] )
2854                                 ? $this->mRestrictions[$action]
2855                                 : array();
2856         }
2857
2858         /**
2859          * Accessor/initialisation for mRestrictions
2860          *
2861          * @return array Keys are actions, values are arrays as returned by
2862          *     Title::getRestrictions()
2863          * @since 1.23
2864          */
2865         public function getAllRestrictions() {
2866                 if ( !$this->mRestrictionsLoaded ) {
2867                         $this->loadRestrictions();
2868                 }
2869                 return $this->mRestrictions;
2870         }
2871
2872         /**
2873          * Get the expiry time for the restriction against a given action
2874          *
2875          * @param string $action
2876          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2877          *     or not protected at all, or false if the action is not recognised.
2878          */
2879         public function getRestrictionExpiry( $action ) {
2880                 if ( !$this->mRestrictionsLoaded ) {
2881                         $this->loadRestrictions();
2882                 }
2883                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2884         }
2885
2886         /**
2887          * Returns cascading restrictions for the current article
2888          *
2889          * @return bool
2890          */
2891         function areRestrictionsCascading() {
2892                 if ( !$this->mRestrictionsLoaded ) {
2893                         $this->loadRestrictions();
2894                 }
2895
2896                 return $this->mCascadeRestriction;
2897         }
2898
2899         /**
2900          * Loads a string into mRestrictions array
2901          *
2902          * @param ResultWrapper $res Resource restrictions as an SQL result.
2903          * @param string $oldFashionedRestrictions Comma-separated list of page
2904          *        restrictions from page table (pre 1.10)
2905          */
2906         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2907                 $rows = array();
2908
2909                 foreach ( $res as $row ) {
2910                         $rows[] = $row;
2911                 }
2912
2913                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2914         }
2915
2916         /**
2917          * Compiles list of active page restrictions from both page table (pre 1.10)
2918          * and page_restrictions table for this existing page.
2919          * Public for usage by LiquidThreads.
2920          *
2921          * @param array $rows Array of db result objects
2922          * @param string $oldFashionedRestrictions Comma-separated list of page
2923          *   restrictions from page table (pre 1.10)
2924          */
2925         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2926                 global $wgContLang;
2927                 $dbr = wfGetDB( DB_SLAVE );
2928
2929                 $restrictionTypes = $this->getRestrictionTypes();
2930
2931                 foreach ( $restrictionTypes as $type ) {
2932                         $this->mRestrictions[$type] = array();
2933                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2934                 }
2935
2936                 $this->mCascadeRestriction = false;
2937
2938                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2939
2940                 if ( $oldFashionedRestrictions === null ) {
2941                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2942                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2943                 }
2944
2945                 if ( $oldFashionedRestrictions != '' ) {
2946
2947                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2948                                 $temp = explode( '=', trim( $restrict ) );
2949                                 if ( count( $temp ) == 1 ) {
2950                                         // old old format should be treated as edit/move restriction
2951                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2952                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2953                                 } else {
2954                                         $restriction = trim( $temp[1] );
2955                                         if ( $restriction != '' ) { //some old entries are empty
2956                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2957                                         }
2958                                 }
2959                         }
2960
2961                         $this->mOldRestrictions = true;
2962
2963                 }
2964
2965                 if ( count( $rows ) ) {
2966                         # Current system - load second to make them override.
2967                         $now = wfTimestampNow();
2968                         $purgeExpired = false;
2969
2970                         # Cycle through all the restrictions.
2971                         foreach ( $rows as $row ) {
2972
2973                                 // Don't take care of restrictions types that aren't allowed
2974                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2975                                         continue;
2976                                 }
2977
2978                                 // This code should be refactored, now that it's being used more generally,
2979                                 // But I don't really see any harm in leaving it in Block for now -werdna
2980                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2981
2982                                 // Only apply the restrictions if they haven't expired!
2983                                 if ( !$expiry || $expiry > $now ) {
2984                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2985                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2986
2987                                         $this->mCascadeRestriction |= $row->pr_cascade;
2988                                 } else {
2989                                         // Trigger a lazy purge of expired restrictions
2990                                         $purgeExpired = true;
2991                                 }
2992                         }
2993
2994                         if ( $purgeExpired ) {
2995                                 Title::purgeExpiredRestrictions();
2996                         }
2997                 }
2998
2999                 $this->mRestrictionsLoaded = true;
3000         }
3001
3002         /**
3003          * Load restrictions from the page_restrictions table
3004          *
3005          * @param string $oldFashionedRestrictions Comma-separated list of page
3006          *   restrictions from page table (pre 1.10)
3007          */
3008         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3009                 global $wgContLang;
3010                 if ( !$this->mRestrictionsLoaded ) {
3011                         if ( $this->exists() ) {
3012                                 $dbr = wfGetDB( DB_SLAVE );
3013
3014                                 $res = $dbr->select(
3015                                         'page_restrictions',
3016                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
3017                                         array( 'pr_page' => $this->getArticleID() ),
3018                                         __METHOD__
3019                                 );
3020
3021                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
3022                         } else {
3023                                 $title_protection = $this->getTitleProtection();
3024
3025                                 if ( $title_protection ) {
3026                                         $now = wfTimestampNow();
3027                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
3028
3029                                         if ( !$expiry || $expiry > $now ) {
3030                                                 // Apply the restrictions
3031                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3032                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
3033                                         } else { // Get rid of the old restrictions
3034                                                 Title::purgeExpiredRestrictions();
3035                                                 $this->mTitleProtection = false;
3036                                         }
3037                                 } else {
3038                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
3039                                 }
3040                                 $this->mRestrictionsLoaded = true;
3041                         }
3042                 }
3043         }
3044
3045         /**
3046          * Flush the protection cache in this object and force reload from the database.
3047          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3048          */
3049         public function flushRestrictions() {
3050                 $this->mRestrictionsLoaded = false;
3051                 $this->mTitleProtection = null;
3052         }
3053
3054         /**
3055          * Purge expired restrictions from the page_restrictions table
3056          */
3057         static function purgeExpiredRestrictions() {
3058                 if ( wfReadOnly() ) {
3059                         return;
3060                 }
3061
3062                 $method = __METHOD__;
3063                 $dbw = wfGetDB( DB_MASTER );
3064                 $dbw->onTransactionIdle( function() use ( $dbw, $method ) {
3065                         $dbw->delete(
3066                                 'page_restrictions',
3067                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3068                                 $method
3069                         );
3070                         $dbw->delete(
3071                                 'protected_titles',
3072                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3073                                 $method
3074                         );
3075                 } );
3076         }
3077
3078         /**
3079          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3080          *
3081          * @return bool
3082          */
3083         public function hasSubpages() {
3084                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3085                         # Duh
3086                         return false;
3087                 }
3088
3089                 # We dynamically add a member variable for the purpose of this method
3090                 # alone to cache the result.  There's no point in having it hanging
3091                 # around uninitialized in every Title object; therefore we only add it
3092                 # if needed and don't declare it statically.
3093                 if ( $this->mHasSubpages === null ) {
3094                         $this->mHasSubpages = false;
3095                         $subpages = $this->getSubpages( 1 );
3096                         if ( $subpages instanceof TitleArray ) {
3097                                 $this->mHasSubpages = (bool)$subpages->count();
3098                         }
3099                 }
3100
3101                 return $this->mHasSubpages;
3102         }
3103
3104         /**
3105          * Get all subpages of this page.
3106          *
3107          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3108          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3109          *  doesn't allow subpages
3110          */
3111         public function getSubpages( $limit = -1 ) {
3112                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3113                         return array();
3114                 }
3115
3116                 $dbr = wfGetDB( DB_SLAVE );
3117                 $conds['page_namespace'] = $this->getNamespace();
3118                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3119                 $options = array();
3120                 if ( $limit > -1 ) {
3121                         $options['LIMIT'] = $limit;
3122                 }
3123                 $this->mSubpages = TitleArray::newFromResult(
3124                         $dbr->select( 'page',
3125                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3126                                 $conds,
3127                                 __METHOD__,
3128                                 $options
3129                         )
3130                 );
3131                 return $this->mSubpages;
3132         }
3133
3134         /**
3135          * Is there a version of this page in the deletion archive?
3136          *
3137          * @return int The number of archived revisions
3138          */
3139         public function isDeleted() {
3140                 if ( $this->getNamespace() < 0 ) {
3141                         $n = 0;
3142                 } else {
3143                         $dbr = wfGetDB( DB_SLAVE );
3144
3145                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3146                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3147                                 __METHOD__
3148                         );
3149                         if ( $this->getNamespace() == NS_FILE ) {
3150                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3151                                         array( 'fa_name' => $this->getDBkey() ),
3152                                         __METHOD__
3153                                 );
3154                         }
3155                 }
3156                 return (int)$n;
3157         }
3158
3159         /**
3160          * Is there a version of this page in the deletion archive?
3161          *
3162          * @return bool
3163          */
3164         public function isDeletedQuick() {
3165                 if ( $this->getNamespace() < 0 ) {
3166                         return false;
3167                 }
3168                 $dbr = wfGetDB( DB_SLAVE );
3169                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3170                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3171                         __METHOD__
3172                 );
3173                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3174                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3175                                 array( 'fa_name' => $this->getDBkey() ),
3176                                 __METHOD__
3177                         );
3178                 }
3179                 return $deleted;
3180         }
3181
3182         /**
3183          * Get the article ID for this Title from the link cache,
3184          * adding it if necessary
3185          *
3186          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3187          *  for update
3188          * @return int The ID
3189          */
3190         public function getArticleID( $flags = 0 ) {
3191                 if ( $this->getNamespace() < 0 ) {
3192                         $this->mArticleID = 0;
3193                         return $this->mArticleID;
3194                 }
3195                 $linkCache = LinkCache::singleton();
3196                 if ( $flags & self::GAID_FOR_UPDATE ) {
3197                         $oldUpdate = $linkCache->forUpdate( true );
3198                         $linkCache->clearLink( $this );
3199                         $this->mArticleID = $linkCache->addLinkObj( $this );
3200                         $linkCache->forUpdate( $oldUpdate );
3201                 } else {
3202                         if ( -1 == $this->mArticleID ) {
3203                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3204                         }
3205                 }
3206                 return $this->mArticleID;
3207         }
3208
3209         /**
3210          * Is this an article that is a redirect page?
3211          * Uses link cache, adding it if necessary
3212          *
3213          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3214          * @return bool
3215          */
3216         public function isRedirect( $flags = 0 ) {
3217                 if ( !is_null( $this->mRedirect ) ) {
3218                         return $this->mRedirect;
3219                 }
3220                 # Calling getArticleID() loads the field from cache as needed
3221                 if ( !$this->getArticleID( $flags ) ) {
3222                         $this->mRedirect = false;
3223                         return $this->mRedirect;
3224                 }
3225
3226                 $linkCache = LinkCache::singleton();
3227                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3228                 if ( $cached === null ) {
3229                         # Trust LinkCache's state over our own
3230                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3231                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3232                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3233                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3234                         # LinkCache to refresh its data from the master.
3235                         $this->mRedirect = false;
3236                         return $this->mRedirect;
3237                 }
3238
3239                 $this->mRedirect = (bool)$cached;
3240
3241                 return $this->mRedirect;
3242         }
3243
3244         /**
3245          * What is the length of this page?
3246          * Uses link cache, adding it if necessary
3247          *
3248          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3249          * @return int
3250          */
3251         public function getLength( $flags = 0 ) {
3252                 if ( $this->mLength != -1 ) {
3253                         return $this->mLength;
3254                 }
3255                 # Calling getArticleID() loads the field from cache as needed
3256                 if ( !$this->getArticleID( $flags ) ) {
3257                         $this->mLength = 0;
3258                         return $this->mLength;
3259                 }
3260                 $linkCache = LinkCache::singleton();
3261                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3262                 if ( $cached === null ) {
3263                         # Trust LinkCache's state over our own, as for isRedirect()
3264                         $this->mLength = 0;
3265                         return $this->mLength;
3266                 }
3267
3268                 $this->mLength = intval( $cached );
3269
3270                 return $this->mLength;
3271         }
3272
3273         /**
3274          * What is the page_latest field for this page?
3275          *
3276          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3277          * @return int Int or 0 if the page doesn't exist
3278          */
3279         public function getLatestRevID( $flags = 0 ) {
3280                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3281                         return intval( $this->mLatestID );
3282                 }
3283                 # Calling getArticleID() loads the field from cache as needed
3284                 if ( !$this->getArticleID( $flags ) ) {
3285                         $this->mLatestID = 0;
3286                         return $this->mLatestID;
3287                 }
3288                 $linkCache = LinkCache::singleton();
3289                 $linkCache->addLinkObj( $this );
3290                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3291                 if ( $cached === null ) {
3292                         # Trust LinkCache's state over our own, as for isRedirect()
3293                         $this->mLatestID = 0;
3294                         return $this->mLatestID;
3295                 }
3296
3297                 $this->mLatestID = intval( $cached );
3298
3299                 return $this->mLatestID;
3300         }
3301
3302         /**
3303          * This clears some fields in this object, and clears any associated
3304          * keys in the "bad links" section of the link cache.
3305          *
3306          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3307          * loading of the new page_id. It's also called from
3308          * WikiPage::doDeleteArticleReal()
3309          *
3310          * @param int $newid The new Article ID
3311          */
3312         public function resetArticleID( $newid ) {
3313                 $linkCache = LinkCache::singleton();
3314                 $linkCache->clearLink( $this );
3315
3316                 if ( $newid === false ) {
3317                         $this->mArticleID = -1;
3318                 } else {
3319                         $this->mArticleID = intval( $newid );
3320                 }
3321                 $this->mRestrictionsLoaded = false;
3322                 $this->mRestrictions = array();
3323                 $this->mRedirect = null;
3324                 $this->mLength = -1;
3325                 $this->mLatestID = false;
3326                 $this->mContentModel = false;
3327                 $this->mEstimateRevisions = null;
3328                 $this->mPageLanguage = false;
3329                 $this->mDbPageLanguage = null;
3330         }
3331
3332         /**
3333          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3334          *
3335          * @param string $text Containing title to capitalize
3336          * @param int $ns Namespace index, defaults to NS_MAIN
3337          * @return string Containing capitalized title
3338          */
3339         public static function capitalize( $text, $ns = NS_MAIN ) {
3340                 global $wgContLang;
3341
3342                 if ( MWNamespace::isCapitalized( $ns ) ) {
3343                         return $wgContLang->ucfirst( $text );
3344                 } else {
3345                         return $text;
3346                 }
3347         }
3348
3349         /**
3350          * Secure and split - main initialisation function for this object
3351          *
3352          * Assumes that mDbkeyform has been set, and is urldecoded
3353          * and uses underscores, but not otherwise munged.  This function
3354          * removes illegal characters, splits off the interwiki and
3355          * namespace prefixes, sets the other forms, and canonicalizes
3356          * everything.
3357          *
3358          * @return bool True on success
3359          */
3360         private function secureAndSplit() {
3361                 # Initialisation
3362                 $this->mInterwiki = '';
3363                 $this->mFragment = '';
3364                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3365
3366                 $dbkey = $this->mDbkeyform;
3367
3368                 try {
3369                         // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3370                         //        the parsing code with Title, while avoiding massive refactoring.
3371                         // @todo: get rid of secureAndSplit, refactor parsing code.
3372                         $parser = $this->getTitleParser();
3373                         $parts = $parser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3374                 } catch ( MalformedTitleException $ex ) {
3375                         return false;
3376                 }
3377
3378                 # Fill fields
3379                 $this->setFragment( '#' . $parts['fragment'] );
3380                 $this->mInterwiki = $parts['interwiki'];
3381                 $this->mNamespace = $parts['namespace'];
3382                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3383
3384                 $this->mDbkeyform = $parts['dbkey'];
3385                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3386                 $this->mTextform = str_replace( '_', ' ', $this->mDbkeyform );
3387
3388                 # We already know that some pages won't be in the database!
3389                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3390                         $this->mArticleID = 0;
3391                 }
3392
3393                 return true;
3394         }
3395
3396         /**
3397          * Get an array of Title objects linking to this Title
3398          * Also stores the IDs in the link cache.
3399          *
3400          * WARNING: do not use this function on arbitrary user-supplied titles!
3401          * On heavily-used templates it will max out the memory.
3402          *
3403          * @param array $options May be FOR UPDATE
3404          * @param string $table Table name
3405          * @param string $prefix Fields prefix
3406          * @return Title[] Array of Title objects linking here
3407          */
3408         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3409                 if ( count( $options ) > 0 ) {
3410                         $db = wfGetDB( DB_MASTER );
3411                 } else {
3412                         $db = wfGetDB( DB_SLAVE );
3413                 }
3414
3415                 $res = $db->select(
3416                         array( 'page', $table ),
3417                         self::getSelectFields(),
3418                         array(
3419                                 "{$prefix}_from=page_id",
3420                                 "{$prefix}_namespace" => $this->getNamespace(),
3421                                 "{$prefix}_title" => $this->getDBkey() ),
3422                         __METHOD__,
3423                         $options
3424                 );
3425
3426                 $retVal = array();
3427                 if ( $res->numRows() ) {
3428                         $linkCache = LinkCache::singleton();
3429                         foreach ( $res as $row ) {
3430                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3431                                 if ( $titleObj ) {
3432                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3433                                         $retVal[] = $titleObj;
3434                                 }
3435                         }
3436                 }
3437                 return $retVal;
3438         }
3439
3440         /**
3441          * Get an array of Title objects using this Title as a template
3442          * Also stores the IDs in the link cache.
3443          *
3444          * WARNING: do not use this function on arbitrary user-supplied titles!
3445          * On heavily-used templates it will max out the memory.
3446          *
3447          * @param array $options May be FOR UPDATE
3448          * @return Title[] Array of Title the Title objects linking here
3449          */
3450         public function getTemplateLinksTo( $options = array() ) {
3451                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3452         }
3453
3454         /**
3455          * Get an array of Title objects linked from this Title
3456          * Also stores the IDs in the link cache.
3457          *
3458          * WARNING: do not use this function on arbitrary user-supplied titles!
3459          * On heavily-used templates it will max out the memory.
3460          *
3461          * @param array $options May be FOR UPDATE
3462          * @param string $table Table name
3463          * @param string $prefix Fields prefix
3464          * @return array Array of Title objects linking here
3465          */
3466         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3467                 global $wgContentHandlerUseDB;
3468
3469                 $id = $this->getArticleID();
3470
3471                 # If the page doesn't exist; there can't be any link from this page
3472                 if ( !$id ) {
3473                         return array();
3474                 }
3475
3476                 if ( count( $options ) > 0 ) {
3477                         $db = wfGetDB( DB_MASTER );
3478                 } else {
3479                         $db = wfGetDB( DB_SLAVE );
3480                 }
3481
3482                 $namespaceFiled = "{$prefix}_namespace";
3483                 $titleField = "{$prefix}_title";
3484
3485                 $fields = array(
3486                         $namespaceFiled,
3487                         $titleField,
3488                         'page_id',
3489                         'page_len',
3490                         'page_is_redirect',
3491                         'page_latest'
3492                 );
3493
3494                 if ( $wgContentHandlerUseDB ) {
3495                         $fields[] = 'page_content_model';
3496                 }
3497
3498                 $res = $db->select(
3499                         array( $table, 'page' ),
3500                         $fields,
3501                         array( "{$prefix}_from" => $id ),
3502                         __METHOD__,
3503                         $options,
3504                         array( 'page' => array(
3505                                 'LEFT JOIN',
3506                                 array( "page_namespace=$namespaceFiled", "page_title=$titleField" )
3507                         ) )
3508                 );
3509
3510                 $retVal = array();
3511                 if ( $res->numRows() ) {
3512                         $linkCache = LinkCache::singleton();
3513                         foreach ( $res as $row ) {
3514                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3515                                 if ( $titleObj ) {
3516                                         if ( $row->page_id ) {
3517                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3518                                         } else {
3519                                                 $linkCache->addBadLinkObj( $titleObj );
3520                                         }
3521                                         $retVal[] = $titleObj;
3522                                 }
3523                         }
3524                 }
3525                 return $retVal;
3526         }
3527
3528         /**
3529          * Get an array of Title objects used on this Title as a template
3530          * Also stores the IDs in the link cache.
3531          *
3532          * WARNING: do not use this function on arbitrary user-supplied titles!
3533          * On heavily-used templates it will max out the memory.
3534          *
3535          * @param array $options May be FOR UPDATE
3536          * @return Title[] Array of Title the Title objects used here
3537          */
3538         public function getTemplateLinksFrom( $options = array() ) {
3539                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3540         }
3541
3542         /**
3543          * Get an array of Title objects referring to non-existent articles linked
3544          * from this page.
3545          *
3546          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3547          *   should use redirect table in this case).
3548          * @return Title[] Array of Title the Title objects
3549          */
3550         public function getBrokenLinksFrom() {
3551                 if ( $this->getArticleID() == 0 ) {
3552                         # All links from article ID 0 are false positives
3553                         return array();
3554                 }
3555
3556                 $dbr = wfGetDB( DB_SLAVE );
3557                 $res = $dbr->select(
3558                         array( 'page', 'pagelinks' ),
3559                         array( 'pl_namespace', 'pl_title' ),
3560                         array(
3561                                 'pl_from' => $this->getArticleID(),
3562                                 'page_namespace IS NULL'
3563                         ),
3564                         __METHOD__, array(),
3565                         array(
3566                                 'page' => array(
3567                                         'LEFT JOIN',
3568                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3569                                 )
3570                         )
3571                 );
3572
3573                 $retVal = array();
3574                 foreach ( $res as $row ) {
3575                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3576                 }
3577                 return $retVal;
3578         }
3579
3580         /**
3581          * Get a list of URLs to purge from the Squid cache when this
3582          * page changes
3583          *
3584          * @return string[] Array of String the URLs
3585          */
3586         public function getSquidURLs() {
3587                 $urls = array(
3588                         $this->getInternalURL(),
3589                         $this->getInternalURL( 'action=history' )
3590                 );
3591
3592                 $pageLang = $this->getPageLanguage();
3593                 if ( $pageLang->hasVariants() ) {
3594                         $variants = $pageLang->getVariants();
3595                         foreach ( $variants as $vCode ) {
3596                                 $urls[] = $this->getInternalURL( '', $vCode );
3597                         }
3598                 }
3599
3600                 // If we are looking at a css/js user subpage, purge the action=raw.
3601                 if ( $this->isJsSubpage() ) {
3602                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3603                 } elseif ( $this->isCssSubpage() ) {
3604                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3605                 }
3606
3607                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3608                 return $urls;
3609         }
3610
3611         /**
3612          * Purge all applicable Squid URLs
3613          */
3614         public function purgeSquid() {
3615                 global $wgUseSquid;
3616                 if ( $wgUseSquid ) {
3617                         $urls = $this->getSquidURLs();
3618                         $u = new SquidUpdate( $urls );
3619                         $u->doUpdate();
3620                 }
3621         }
3622
3623         /**
3624          * Move this page without authentication
3625          *
3626          * @param Title $nt The new page Title
3627          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3628          */
3629         public function moveNoAuth( &$nt ) {
3630                 return $this->moveTo( $nt, false );
3631         }
3632
3633         /**
3634          * Check whether a given move operation would be valid.
3635          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3636          *
3637          * @param Title $nt The new title
3638          * @param bool $auth Indicates whether $wgUser's permissions
3639          *  should be checked
3640          * @param string $reason Is the log summary of the move, used for spam checking
3641          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3642          */
3643         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3644                 global $wgUser, $wgContentHandlerUseDB;
3645
3646                 $errors = array();
3647                 if ( !$nt ) {
3648                         // Normally we'd add this to $errors, but we'll get
3649                         // lots of syntax errors if $nt is not an object
3650                         return array( array( 'badtitletext' ) );
3651                 }
3652                 if ( $this->equals( $nt ) ) {
3653                         $errors[] = array( 'selfmove' );
3654                 }
3655                 if ( !$this->isMovable() ) {
3656                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3657                 }
3658                 if ( $nt->isExternal() ) {
3659                         $errors[] = array( 'immobile-target-namespace-iw' );
3660                 }
3661                 if ( !$nt->isMovable() ) {
3662                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3663                 }
3664
3665                 $oldid = $this->getArticleID();
3666                 $newid = $nt->getArticleID();
3667
3668                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3669                         $errors[] = array( 'articleexists' );
3670                 }
3671                 if (
3672                         ( $this->getDBkey() == '' ) ||
3673                         ( !$oldid ) ||
3674                         ( $nt->getDBkey() == '' )
3675                 ) {
3676                         $errors[] = array( 'badarticleerror' );
3677                 }
3678
3679                 // Content model checks
3680                 if ( !$wgContentHandlerUseDB &&
3681                                 $this->getContentModel() !== $nt->getContentModel() ) {
3682                         // can't move a page if that would change the page's content model
3683                         $errors[] = array(
3684                                 'bad-target-model',
3685                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3686                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3687                         );
3688                 }
3689
3690                 // Image-specific checks
3691                 if ( $this->getNamespace() == NS_FILE ) {
3692                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3693                 }
3694
3695                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3696                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3697                 }
3698
3699                 if ( $auth ) {
3700                         $errors = wfMergeErrorArrays( $errors,
3701                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3702                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3703                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3704                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3705                 }
3706
3707                 $match = EditPage::matchSummarySpamRegex( $reason );
3708                 if ( $match !== false ) {
3709                         // This is kind of lame, won't display nice
3710                         $errors[] = array( 'spamprotectiontext' );
3711                 }
3712
3713                 $err = null;
3714                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3715                         $errors[] = array( 'hookaborted', $err );
3716                 }
3717
3718                 # The move is allowed only if (1) the target doesn't exist, or
3719                 # (2) the target is a redirect to the source, and has no history
3720                 # (so we can undo bad moves right after they're done).
3721
3722                 if ( 0 != $newid ) { # Target exists; check for validity
3723                         if ( !$this->isValidMoveTarget( $nt ) ) {
3724                                 $errors[] = array( 'articleexists' );
3725                         }
3726                 } else {
3727                         $tp = $nt->getTitleProtection();
3728                         $right = $tp['pt_create_perm'];
3729                         if ( $right == 'sysop' ) {
3730                                 $right = 'editprotected'; // B/C
3731                         }
3732                         if ( $right == 'autoconfirmed' ) {
3733                                 $right = 'editsemiprotected'; // B/C
3734                         }
3735                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3736                                 $errors[] = array( 'cantmove-titleprotected' );
3737                         }
3738                 }
3739                 if ( empty( $errors ) ) {
3740                         return true;
3741                 }
3742                 return $errors;
3743         }
3744
3745         /**
3746          * Check if the requested move target is a valid file move target
3747          * @param Title $nt Target title
3748          * @return array List of errors
3749          */
3750         protected function validateFileMoveOperation( $nt ) {
3751                 global $wgUser;
3752
3753                 $errors = array();
3754
3755                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3756
3757                 $file = wfLocalFile( $this );
3758                 if ( $file->exists() ) {
3759                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3760                                 $errors[] = array( 'imageinvalidfilename' );
3761                         }
3762                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3763                                 $errors[] = array( 'imagetypemismatch' );
3764                         }
3765                 }
3766
3767                 if ( $nt->getNamespace() != NS_FILE ) {
3768                         $errors[] = array( 'imagenocrossnamespace' );
3769                         // From here we want to do checks on a file object, so if we can't
3770                         // create one, we must return.
3771                         return $errors;
3772                 }
3773
3774                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3775
3776                 $destFile = wfLocalFile( $nt );
3777                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3778                         $errors[] = array( 'file-exists-sharedrepo' );
3779                 }
3780
3781                 return $errors;
3782         }
3783
3784         /**
3785          * Move a title to a new location
3786          *
3787          * @param Title $nt The new title
3788          * @param bool $auth Indicates whether $wgUser's permissions
3789          *  should be checked
3790          * @param string $reason The reason for the move
3791          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3792          *  Ignored if the user doesn't have the suppressredirect right.
3793          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3794          */
3795         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3796                 global $wgUser;
3797                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3798                 if ( is_array( $err ) ) {
3799                         // Auto-block user's IP if the account was "hard" blocked
3800                         $wgUser->spreadAnyEditBlock();
3801                         return $err;
3802                 }
3803                 // Check suppressredirect permission
3804                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3805                         $createRedirect = true;
3806                 }
3807
3808                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3809
3810                 // If it is a file, move it first.
3811                 // It is done before all other moving stuff is done because it's hard to revert.
3812                 $dbw = wfGetDB( DB_MASTER );
3813                 if ( $this->getNamespace() == NS_FILE ) {
3814                         $file = wfLocalFile( $this );
3815                         if ( $file->exists() ) {
3816                                 $status = $file->move( $nt );
3817                                 if ( !$status->isOk() ) {
3818                                         return $status->getErrorsArray();
3819                                 }
3820                         }
3821                         // Clear RepoGroup process cache
3822                         RepoGroup::singleton()->clearCache( $this );
3823                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3824                 }
3825
3826                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3827                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3828                 $protected = $this->isProtected();
3829
3830                 // Do the actual move
3831                 $this->moveToInternal( $nt, $reason, $createRedirect );
3832
3833                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3834                 // cl_timestamp, which may disturb time-based lists on some sites.
3835                 $prefixes = $dbw->select(
3836                         'categorylinks',
3837                         array( 'cl_sortkey_prefix', 'cl_to' ),
3838                         array( 'cl_from' => $pageid ),
3839                         __METHOD__
3840                 );
3841                 foreach ( $prefixes as $prefixRow ) {
3842                         $prefix = $prefixRow->cl_sortkey_prefix;
3843                         $catTo = $prefixRow->cl_to;
3844                         $dbw->update( 'categorylinks',
3845                                 array(
3846                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3847                                                 $nt->getCategorySortkey( $prefix ) ),
3848                                         'cl_timestamp=cl_timestamp' ),
3849                                 array(
3850                                         'cl_from' => $pageid,
3851                                         'cl_to' => $catTo ),
3852                                 __METHOD__
3853                         );
3854                 }
3855
3856                 $redirid = $this->getArticleID();
3857
3858                 if ( $protected ) {
3859                         # Protect the redirect title as the title used to be...
3860                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3861                                 array(
3862                                         'pr_page' => $redirid,
3863                                         'pr_type' => 'pr_type',
3864                                         'pr_level' => 'pr_level',
3865                                         'pr_cascade' => 'pr_cascade',
3866                                         'pr_user' => 'pr_user',
3867                                         'pr_expiry' => 'pr_expiry'
3868                                 ),
3869                                 array( 'pr_page' => $pageid ),
3870                                 __METHOD__,
3871                                 array( 'IGNORE' )
3872                         );
3873                         # Update the protection log
3874                         $log = new LogPage( 'protect' );
3875                         $comment = wfMessage(
3876                                 'prot_1movedto2',
3877                                 $this->getPrefixedText(),
3878                                 $nt->getPrefixedText()
3879                         )->inContentLanguage()->text();
3880                         if ( $reason ) {
3881                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3882                         }
3883                         // @todo FIXME: $params?
3884                         $logId = $log->addEntry(
3885                                 'move_prot',
3886                                 $nt,
3887                                 $comment,
3888                                 array( $this->getPrefixedText() ),
3889                                 $wgUser
3890                         );
3891
3892                         // reread inserted pr_ids for log relation
3893                         $insertedPrIds = $dbw->select(
3894                                 'page_restrictions',
3895                                 'pr_id',
3896                                 array( 'pr_page' => $redirid ),
3897                                 __METHOD__
3898                         );
3899                         $logRelationsValues = array();
3900                         foreach ( $insertedPrIds as $prid ) {
3901                                 $logRelationsValues[] = $prid->pr_id;
3902                         }
3903                         $log->addRelations( 'pr_id', $logRelationsValues, $logId );
3904                 }
3905
3906                 # Update watchlists
3907                 $oldnamespace = MWNamespace::getSubject( $this->getNamespace() );
3908                 $newnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3909                 $oldtitle = $this->getDBkey();
3910                 $newtitle = $nt->getDBkey();
3911
3912                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3913                         WatchedItem::duplicateEntries( $this, $nt );
3914                 }
3915
3916                 $dbw->commit( __METHOD__ );
3917
3918                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid, $reason ) );
3919                 return true;
3920         }
3921
3922         /**
3923          * Move page to a title which is either a redirect to the
3924          * source page or nonexistent
3925          *
3926          * @param Title $nt The page to move to, which should be a redirect or nonexistent
3927          * @param string $reason The reason for the move
3928          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3929          *   if the user has the suppressredirect right
3930          * @throws MWException
3931          */
3932         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3933                 global $wgUser, $wgContLang;
3934
3935                 if ( $nt->exists() ) {
3936                         $moveOverRedirect = true;
3937                         $logType = 'move_redir';
3938                 } else {
3939                         $moveOverRedirect = false;
3940                         $logType = 'move';
3941                 }
3942
3943                 if ( $createRedirect ) {
3944                         if ( $this->getNamespace() == NS_CATEGORY
3945                                 && !wfMessage( 'category-move-redirect-override' )->inContentLanguage()->isDisabled()
3946                         ) {
3947                                 $redirectContent = new WikitextContent(
3948                                         wfMessage( 'category-move-redirect-override' )
3949                                                 ->params( $nt->getPrefixedText() )->inContentLanguage()->plain() );
3950                         } else {
3951                                 $contentHandler = ContentHandler::getForTitle( $this );
3952                                 $redirectContent = $contentHandler->makeRedirectContent( $nt,
3953                                         wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3954                         }
3955
3956                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3957                 } else {
3958                         $redirectContent = null;
3959                 }
3960
3961                 $logEntry = new ManualLogEntry( 'move', $logType );
3962                 $logEntry->setPerformer( $wgUser );
3963                 $logEntry->setTarget( $this );
3964                 $logEntry->setComment( $reason );
3965                 $logEntry->setParameters( array(
3966                         '4::target' => $nt->getPrefixedText(),
3967                         '5::noredir' => $redirectContent ? '0': '1',
3968                 ) );
3969
3970                 $formatter = LogFormatter::newFromEntry( $logEntry );
3971                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3972                 $comment = $formatter->getPlainActionText();
3973                 if ( $reason ) {
3974                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3975                 }
3976                 # Truncate for whole multibyte characters.
3977                 $comment = $wgContLang->truncate( $comment, 255 );
3978
3979                 $oldid = $this->getArticleID();
3980
3981                 $dbw = wfGetDB( DB_MASTER );
3982
3983                 $newpage = WikiPage::factory( $nt );
3984
3985                 if ( $moveOverRedirect ) {
3986                         $newid = $nt->getArticleID();
3987                         $newcontent = $newpage->getContent();
3988
3989                         # Delete the old redirect. We don't save it to history since
3990                         # by definition if we've got here it's rather uninteresting.
3991                         # We have to remove it so that the next step doesn't trigger
3992                         # a conflict on the unique namespace+title index...
3993                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3994
3995                         $newpage->doDeleteUpdates( $newid, $newcontent );
3996                 }
3997
3998                 # Save a null revision in the page's history notifying of the move
3999                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true, $wgUser );
4000                 if ( !is_object( $nullRevision ) ) {
4001                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
4002                 }
4003
4004                 $nullRevision->insertOn( $dbw );
4005
4006                 # Change the name of the target page:
4007                 $dbw->update( 'page',
4008                         /* SET */ array(
4009                                 'page_namespace' => $nt->getNamespace(),
4010                                 'page_title' => $nt->getDBkey(),
4011                         ),
4012                         /* WHERE */ array( 'page_id' => $oldid ),
4013                         __METHOD__
4014                 );
4015
4016                 // clean up the old title before reset article id - bug 45348
4017                 if ( !$redirectContent ) {
4018                         WikiPage::onArticleDelete( $this );
4019                 }
4020
4021                 $this->resetArticleID( 0 ); // 0 == non existing
4022                 $nt->resetArticleID( $oldid );
4023                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
4024
4025                 $newpage->updateRevisionOn( $dbw, $nullRevision );
4026
4027                 wfRunHooks( 'NewRevisionFromEditComplete',
4028                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
4029
4030                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
4031
4032                 if ( !$moveOverRedirect ) {
4033                         WikiPage::onArticleCreate( $nt );
4034                 }
4035
4036                 # Recreate the redirect, this time in the other direction.
4037                 if ( $redirectContent ) {
4038                         $redirectArticle = WikiPage::factory( $this );
4039                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
4040                         $newid = $redirectArticle->insertOn( $dbw );
4041                         if ( $newid ) { // sanity
4042                                 $this->resetArticleID( $newid );
4043                                 $redirectRevision = new Revision( array(
4044                                         'title' => $this, // for determining the default content model
4045                                         'page' => $newid,
4046                                         'user_text' => $wgUser->getName(),
4047                                         'user' => $wgUser->getId(),
4048                                         'comment' => $comment,
4049                                         'content' => $redirectContent ) );
4050                                 $redirectRevision->insertOn( $dbw );
4051                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
4052
4053                                 wfRunHooks( 'NewRevisionFromEditComplete',
4054                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
4055
4056                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
4057                         }
4058                 }
4059
4060                 # Log the move
4061                 $logid = $logEntry->insert();
4062                 $logEntry->publish( $logid );
4063         }
4064
4065         /**
4066          * Move this page's subpages to be subpages of $nt
4067          *
4068          * @param Title $nt Move target
4069          * @param bool $auth Whether $wgUser's permissions should be checked
4070          * @param string $reason The reason for the move
4071          * @param bool $createRedirect Whether to create redirects from the old subpages to
4072          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4073          * @return array Array with old page titles as keys, and strings (new page titles) or
4074          *     arrays (errors) as values, or an error array with numeric indices if no pages
4075          *     were moved
4076          */
4077         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
4078                 global $wgMaximumMovedPages;
4079                 // Check permissions
4080                 if ( !$this->userCan( 'move-subpages' ) ) {
4081                         return array( 'cant-move-subpages' );
4082                 }
4083                 // Do the source and target namespaces support subpages?
4084                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4085                         return array( 'namespace-nosubpages',
4086                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
4087                 }
4088                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4089                         return array( 'namespace-nosubpages',
4090                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
4091                 }
4092
4093                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4094                 $retval = array();
4095                 $count = 0;
4096                 foreach ( $subpages as $oldSubpage ) {
4097                         $count++;
4098                         if ( $count > $wgMaximumMovedPages ) {
4099                                 $retval[$oldSubpage->getPrefixedText()] =
4100                                                 array( 'movepage-max-pages',
4101                                                         $wgMaximumMovedPages );
4102                                 break;
4103                         }
4104
4105                         // We don't know whether this function was called before
4106                         // or after moving the root page, so check both
4107                         // $this and $nt
4108                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4109                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4110                         ) {
4111                                 // When moving a page to a subpage of itself,
4112                                 // don't move it twice
4113                                 continue;
4114                         }
4115                         $newPageName = preg_replace(
4116                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4117                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4118                                         $oldSubpage->getDBkey() );
4119                         if ( $oldSubpage->isTalkPage() ) {
4120                                 $newNs = $nt->getTalkPage()->getNamespace();
4121                         } else {
4122                                 $newNs = $nt->getSubjectPage()->getNamespace();
4123                         }
4124                         # Bug 14385: we need makeTitleSafe because the new page names may
4125                         # be longer than 255 characters.
4126                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4127
4128                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4129                         if ( $success === true ) {
4130                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4131                         } else {
4132                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4133                         }
4134                 }
4135                 return $retval;
4136         }
4137
4138         /**
4139          * Checks if this page is just a one-rev redirect.
4140          * Adds lock, so don't use just for light purposes.
4141          *
4142          * @return bool
4143          */
4144         public function isSingleRevRedirect() {
4145                 global $wgContentHandlerUseDB;
4146
4147                 $dbw = wfGetDB( DB_MASTER );
4148
4149                 # Is it a redirect?
4150                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4151                 if ( $wgContentHandlerUseDB ) {
4152                         $fields[] = 'page_content_model';
4153                 }
4154
4155                 $row = $dbw->selectRow( 'page',
4156                         $fields,
4157                         $this->pageCond(),
4158                         __METHOD__,
4159                         array( 'FOR UPDATE' )
4160                 );
4161                 # Cache some fields we may want
4162                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4163                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4164                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4165                 $this->mContentModel = $row && isset( $row->page_content_model )
4166                         ? strval( $row->page_content_model )
4167                         : false;
4168
4169                 if ( !$this->mRedirect ) {
4170                         return false;
4171                 }
4172                 # Does the article have a history?
4173                 $row = $dbw->selectField( array( 'page', 'revision' ),
4174                         'rev_id',
4175                         array( 'page_namespace' => $this->getNamespace(),
4176                                 'page_title' => $this->getDBkey(),
4177                                 'page_id=rev_page',
4178                                 'page_latest != rev_id'
4179                         ),
4180                         __METHOD__,
4181                         array( 'FOR UPDATE' )
4182                 );
4183                 # Return true if there was no history
4184                 return ( $row === false );
4185         }
4186
4187         /**
4188          * Checks if $this can be moved to a given Title
4189          * - Selects for update, so don't call it unless you mean business
4190          *
4191          * @param Title $nt The new title to check
4192          * @return bool
4193          */
4194         public function isValidMoveTarget( $nt ) {
4195                 # Is it an existing file?
4196                 if ( $nt->getNamespace() == NS_FILE ) {
4197                         $file = wfLocalFile( $nt );
4198                         if ( $file->exists() ) {
4199                                 wfDebug( __METHOD__ . ": file exists\n" );
4200                                 return false;
4201                         }
4202                 }
4203                 # Is it a redirect with no history?
4204                 if ( !$nt->isSingleRevRedirect() ) {
4205                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4206                         return false;
4207                 }
4208                 # Get the article text
4209                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4210                 if ( !is_object( $rev ) ) {
4211                         return false;
4212                 }
4213                 $content = $rev->getContent();
4214                 # Does the redirect point to the source?
4215                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4216                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4217
4218                 if ( $redirTitle ) {
4219                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4220                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4221                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4222                                 return false;
4223                         } else {
4224                                 return true;
4225                         }
4226                 } else {
4227                         # Fail safe (not a redirect after all. strange.)
4228                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4229                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4230                         return false;
4231                 }
4232         }
4233
4234         /**
4235          * Get categories to which this Title belongs and return an array of
4236          * categories' names.
4237          *
4238          * @return array Array of parents in the form:
4239          *        $parent => $currentarticle
4240          */
4241         public function getParentCategories() {
4242                 global $wgContLang;
4243
4244                 $data = array();
4245
4246                 $titleKey = $this->getArticleID();
4247
4248                 if ( $titleKey === 0 ) {
4249                         return $data;
4250                 }
4251
4252                 $dbr = wfGetDB( DB_SLAVE );
4253
4254                 $res = $dbr->select(
4255                         'categorylinks',
4256                         'cl_to',
4257                         array( 'cl_from' => $titleKey ),
4258                         __METHOD__
4259                 );
4260
4261                 if ( $res->numRows() > 0 ) {
4262                         foreach ( $res as $row ) {
4263                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4264                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4265                         }
4266                 }
4267                 return $data;
4268         }
4269
4270         /**
4271          * Get a tree of parent categories
4272          *
4273          * @param array $children Array with the children in the keys, to check for circular refs
4274          * @return array Tree of parent categories
4275          */
4276         public function getParentCategoryTree( $children = array() ) {
4277                 $stack = array();
4278                 $parents = $this->getParentCategories();
4279
4280                 if ( $parents ) {
4281                         foreach ( $parents as $parent => $current ) {
4282                                 if ( array_key_exists( $parent, $children ) ) {
4283                                         # Circular reference
4284                                         $stack[$parent] = array();
4285                                 } else {
4286                                         $nt = Title::newFromText( $parent );
4287                                         if ( $nt ) {
4288                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4289                                         }
4290                                 }
4291                         }
4292                 }
4293
4294                 return $stack;
4295         }
4296
4297         /**
4298          * Get an associative array for selecting this title from
4299          * the "page" table
4300          *
4301          * @return array Array suitable for the $where parameter of DB::select()
4302          */
4303         public function pageCond() {
4304                 if ( $this->mArticleID > 0 ) {
4305                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4306                         return array( 'page_id' => $this->mArticleID );
4307                 } else {
4308                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4309                 }
4310         }
4311
4312         /**
4313          * Get the revision ID of the previous revision
4314          *
4315          * @param int $revId Revision ID. Get the revision that was before this one.
4316          * @param int $flags Title::GAID_FOR_UPDATE
4317          * @return int|bool Old revision ID, or false if none exists
4318          */
4319         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4320                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4321                 $revId = $db->selectField( 'revision', 'rev_id',
4322                         array(
4323                                 'rev_page' => $this->getArticleID( $flags ),
4324                                 'rev_id < ' . intval( $revId )
4325                         ),
4326                         __METHOD__,
4327                         array( 'ORDER BY' => 'rev_id DESC' )
4328                 );
4329
4330                 if ( $revId === false ) {
4331                         return false;
4332                 } else {
4333                         return intval( $revId );
4334                 }
4335         }
4336
4337         /**
4338          * Get the revision ID of the next revision
4339          *
4340          * @param int $revId Revision ID. Get the revision that was after this one.
4341          * @param int $flags Title::GAID_FOR_UPDATE
4342          * @return int|bool Next revision ID, or false if none exists
4343          */
4344         public function getNextRevisionID( $revId, $flags = 0 ) {
4345                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4346                 $revId = $db->selectField( 'revision', 'rev_id',
4347                         array(
4348                                 'rev_page' => $this->getArticleID( $flags ),
4349                                 'rev_id > ' . intval( $revId )
4350                         ),
4351                         __METHOD__,
4352                         array( 'ORDER BY' => 'rev_id' )
4353                 );
4354
4355                 if ( $revId === false ) {
4356                         return false;
4357                 } else {
4358                         return intval( $revId );
4359                 }
4360         }
4361
4362         /**
4363          * Get the first revision of the page
4364          *
4365          * @param int $flags Title::GAID_FOR_UPDATE
4366          * @return Revision|null If page doesn't exist
4367          */
4368         public function getFirstRevision( $flags = 0 ) {
4369                 $pageId = $this->getArticleID( $flags );
4370                 if ( $pageId ) {
4371                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4372                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4373                                 array( 'rev_page' => $pageId ),
4374                                 __METHOD__,
4375                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4376                         );
4377                         if ( $row ) {
4378                                 return new Revision( $row );
4379                         }
4380                 }
4381                 return null;
4382         }
4383
4384         /**
4385          * Get the oldest revision timestamp of this page
4386          *
4387          * @param int $flags Title::GAID_FOR_UPDATE
4388          * @return string MW timestamp
4389          */
4390         public function getEarliestRevTime( $flags = 0 ) {
4391                 $rev = $this->getFirstRevision( $flags );
4392                 return $rev ? $rev->getTimestamp() : null;
4393         }
4394
4395         /**
4396          * Check if this is a new page
4397          *
4398          * @return bool
4399          */
4400         public function isNewPage() {
4401                 $dbr = wfGetDB( DB_SLAVE );
4402                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4403         }
4404
4405         /**
4406          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4407          *
4408          * @return bool
4409          */
4410         public function isBigDeletion() {
4411                 global $wgDeleteRevisionsLimit;
4412
4413                 if ( !$wgDeleteRevisionsLimit ) {
4414                         return false;
4415                 }
4416
4417                 $revCount = $this->estimateRevisionCount();
4418                 return $revCount > $wgDeleteRevisionsLimit;
4419         }
4420
4421         /**
4422          * Get the  approximate revision count of this page.
4423          *
4424          * @return int
4425          */
4426         public function estimateRevisionCount() {
4427                 if ( !$this->exists() ) {
4428                         return 0;
4429                 }
4430
4431                 if ( $this->mEstimateRevisions === null ) {
4432                         $dbr = wfGetDB( DB_SLAVE );
4433                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4434                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4435                 }
4436
4437                 return $this->mEstimateRevisions;
4438         }
4439
4440         /**
4441          * Get the number of revisions between the given revision.
4442          * Used for diffs and other things that really need it.
4443          *
4444          * @param int|Revision $old Old revision or rev ID (first before range)
4445          * @param int|Revision $new New revision or rev ID (first after range)
4446          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4447          * @return int Number of revisions between these revisions.
4448          */
4449         public function countRevisionsBetween( $old, $new, $max = null ) {
4450                 if ( !( $old instanceof Revision ) ) {
4451                         $old = Revision::newFromTitle( $this, (int)$old );
4452                 }
4453                 if ( !( $new instanceof Revision ) ) {
4454                         $new = Revision::newFromTitle( $this, (int)$new );
4455                 }
4456                 if ( !$old || !$new ) {
4457                         return 0; // nothing to compare
4458                 }
4459                 $dbr = wfGetDB( DB_SLAVE );
4460                 $conds = array(
4461                         'rev_page' => $this->getArticleID(),
4462                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4463                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4464                 );
4465                 if ( $max !== null ) {
4466                         $res = $dbr->select( 'revision', '1',
4467                                 $conds,
4468                                 __METHOD__,
4469                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4470                         );
4471                         return $res->numRows();
4472                 } else {
4473                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4474                 }
4475         }
4476
4477         /**
4478          * Get the authors between the given revisions or revision IDs.
4479          * Used for diffs and other things that really need it.
4480          *
4481          * @since 1.23
4482          *
4483          * @param int|Revision $old Old revision or rev ID (first before range by default)
4484          * @param int|Revision $new New revision or rev ID (first after range by default)
4485          * @param int $limit Maximum number of authors
4486          * @param string|array $options (Optional): Single option, or an array of options:
4487          *     'include_old' Include $old in the range; $new is excluded.
4488          *     'include_new' Include $new in the range; $old is excluded.
4489          *     'include_both' Include both $old and $new in the range.
4490          *     Unknown option values are ignored.
4491          * @return array|null Names of revision authors in the range; null if not both revisions exist
4492          */
4493         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4494                 if ( !( $old instanceof Revision ) ) {
4495                         $old = Revision::newFromTitle( $this, (int)$old );
4496                 }
4497                 if ( !( $new instanceof Revision ) ) {
4498                         $new = Revision::newFromTitle( $this, (int)$new );
4499                 }
4500                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4501                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4502                 // in the sanity check below?
4503                 if ( !$old || !$new ) {
4504                         return null; // nothing to compare
4505                 }
4506                 $authors = array();
4507                 $old_cmp = '>';
4508                 $new_cmp = '<';
4509                 $options = (array)$options;
4510                 if ( in_array( 'include_old', $options ) ) {
4511                         $old_cmp = '>=';
4512                 }
4513                 if ( in_array( 'include_new', $options ) ) {
4514                         $new_cmp = '<=';
4515                 }
4516                 if ( in_array( 'include_both', $options ) ) {
4517                         $old_cmp = '>=';
4518                         $new_cmp = '<=';
4519                 }
4520                 // No DB query needed if $old and $new are the same or successive revisions:
4521                 if ( $old->getId() === $new->getId() ) {
4522                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? array() : array( $old->getRawUserText() );
4523                 } elseif ( $old->getId() === $new->getParentId() ) {
4524                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4525                                 $authors[] = $old->getRawUserText();
4526                                 if ( $old->getRawUserText() != $new->getRawUserText() ) {
4527                                         $authors[] = $new->getRawUserText();
4528                                 }
4529                         } elseif ( $old_cmp === '>=' ) {
4530                                 $authors[] = $old->getRawUserText();
4531                         } elseif ( $new_cmp === '<=' ) {
4532                                 $authors[] = $new->getRawUserText();
4533                         }
4534                         return $authors;
4535                 }
4536                 $dbr = wfGetDB( DB_SLAVE );
4537                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4538                         array(
4539                                 'rev_page' => $this->getArticleID(),
4540                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4541                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4542                         ), __METHOD__,
4543                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4544                 );
4545                 foreach ( $res as $row ) {
4546                         $authors[] = $row->rev_user_text;
4547                 }
4548                 return $authors;
4549         }
4550
4551         /**
4552          * Get the number of authors between the given revisions or revision IDs.
4553          * Used for diffs and other things that really need it.
4554          *
4555          * @param int|Revision $old Old revision or rev ID (first before range by default)
4556          * @param int|Revision $new New revision or rev ID (first after range by default)
4557          * @param int $limit Maximum number of authors
4558          * @param string|array $options (Optional): Single option, or an array of options:
4559          *     'include_old' Include $old in the range; $new is excluded.
4560          *     'include_new' Include $new in the range; $old is excluded.
4561          *     'include_both' Include both $old and $new in the range.
4562          *     Unknown option values are ignored.
4563          * @return int Number of revision authors in the range; zero if not both revisions exist
4564          */
4565         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4566                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4567                 return $authors ? count( $authors ) : 0;
4568         }
4569
4570         /**
4571          * Compare with another title.
4572          *
4573          * @param Title $title
4574          * @return bool
4575          */
4576         public function equals( Title $title ) {
4577                 // Note: === is necessary for proper matching of number-like titles.
4578                 return $this->getInterwiki() === $title->getInterwiki()
4579                         && $this->getNamespace() == $title->getNamespace()
4580                         && $this->getDBkey() === $title->getDBkey();
4581         }
4582
4583         /**
4584          * Check if this title is a subpage of another title
4585          *
4586          * @param Title $title
4587          * @return bool
4588          */
4589         public function isSubpageOf( Title $title ) {
4590                 return $this->getInterwiki() === $title->getInterwiki()
4591                         && $this->getNamespace() == $title->getNamespace()
4592                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4593         }
4594
4595         /**
4596          * Check if page exists.  For historical reasons, this function simply
4597          * checks for the existence of the title in the page table, and will
4598          * thus return false for interwiki links, special pages and the like.
4599          * If you want to know if a title can be meaningfully viewed, you should
4600          * probably call the isKnown() method instead.
4601          *
4602          * @return bool
4603          */
4604         public function exists() {
4605                 return $this->getArticleID() != 0;
4606         }
4607
4608         /**
4609          * Should links to this title be shown as potentially viewable (i.e. as
4610          * "bluelinks"), even if there's no record by this title in the page
4611          * table?
4612          *
4613          * This function is semi-deprecated for public use, as well as somewhat
4614          * misleadingly named.  You probably just want to call isKnown(), which
4615          * calls this function internally.
4616          *
4617          * (ISSUE: Most of these checks are cheap, but the file existence check
4618          * can potentially be quite expensive.  Including it here fixes a lot of
4619          * existing code, but we might want to add an optional parameter to skip
4620          * it and any other expensive checks.)
4621          *
4622          * @return bool
4623          */
4624         public function isAlwaysKnown() {
4625                 $isKnown = null;
4626
4627                 /**
4628                  * Allows overriding default behavior for determining if a page exists.
4629                  * If $isKnown is kept as null, regular checks happen. If it's
4630                  * a boolean, this value is returned by the isKnown method.
4631                  *
4632                  * @since 1.20
4633                  *
4634                  * @param Title $title
4635                  * @param bool|null $isKnown
4636                  */
4637                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4638
4639                 if ( !is_null( $isKnown ) ) {
4640                         return $isKnown;
4641                 }
4642
4643                 if ( $this->isExternal() ) {
4644                         return true;  // any interwiki link might be viewable, for all we know
4645                 }
4646
4647                 switch ( $this->mNamespace ) {
4648                         case NS_MEDIA:
4649                         case NS_FILE:
4650                                 // file exists, possibly in a foreign repo
4651                                 return (bool)wfFindFile( $this );
4652                         case NS_SPECIAL:
4653                                 // valid special page
4654                                 return SpecialPageFactory::exists( $this->getDBkey() );
4655                         case NS_MAIN:
4656                                 // selflink, possibly with fragment
4657                                 return $this->mDbkeyform == '';
4658                         case NS_MEDIAWIKI:
4659                                 // known system message
4660                                 return $this->hasSourceText() !== false;
4661                         default:
4662                                 return false;
4663                 }
4664         }
4665
4666         /**
4667          * Does this title refer to a page that can (or might) be meaningfully
4668          * viewed?  In particular, this function may be used to determine if
4669          * links to the title should be rendered as "bluelinks" (as opposed to
4670          * "redlinks" to non-existent pages).
4671          * Adding something else to this function will cause inconsistency
4672          * since LinkHolderArray calls isAlwaysKnown() and does its own
4673          * page existence check.
4674          *
4675          * @return bool
4676          */
4677         public function isKnown() {
4678                 return $this->isAlwaysKnown() || $this->exists();
4679         }
4680
4681         /**
4682          * Does this page have source text?
4683          *
4684          * @return bool
4685          */
4686         public function hasSourceText() {
4687                 if ( $this->exists() ) {
4688                         return true;
4689                 }
4690
4691                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4692                         // If the page doesn't exist but is a known system message, default
4693                         // message content will be displayed, same for language subpages-
4694                         // Use always content language to avoid loading hundreds of languages
4695                         // to get the link color.
4696                         global $wgContLang;
4697                         list( $name, ) = MessageCache::singleton()->figureMessage(
4698                                 $wgContLang->lcfirst( $this->getText() )
4699                         );
4700                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4701                         return $message->exists();
4702                 }
4703
4704                 return false;
4705         }
4706
4707         /**
4708          * Get the default message text or false if the message doesn't exist
4709          *
4710          * @return string|bool
4711          */
4712         public function getDefaultMessageText() {
4713                 global $wgContLang;
4714
4715                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4716                         return false;
4717                 }
4718
4719                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4720                         $wgContLang->lcfirst( $this->getText() )
4721                 );
4722                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4723
4724                 if ( $message->exists() ) {
4725                         return $message->plain();
4726                 } else {
4727                         return false;
4728                 }
4729         }
4730
4731         /**
4732          * Updates page_touched for this page; called from LinksUpdate.php
4733          *
4734          * @return bool True if the update succeeded
4735          */
4736         public function invalidateCache() {
4737                 if ( wfReadOnly() ) {
4738                         return false;
4739                 }
4740
4741                 if ( $this->mArticleID === 0 ) {
4742                         return true; // avoid gap locking if we know it's not there
4743                 }
4744
4745                 $method = __METHOD__;
4746                 $dbw = wfGetDB( DB_MASTER );
4747                 $conds = $this->pageCond();
4748                 $dbw->onTransactionIdle( function() use ( $dbw, $conds, $method ) {
4749                         $dbw->update(
4750                                 'page',
4751                                 array( 'page_touched' => $dbw->timestamp() ),
4752                                 $conds,
4753                                 $method
4754                         );
4755                 } );
4756
4757                 return true;
4758         }
4759
4760         /**
4761          * Update page_touched timestamps and send squid purge messages for
4762          * pages linking to this title. May be sent to the job queue depending
4763          * on the number of links. Typically called on create and delete.
4764          */
4765         public function touchLinks() {
4766                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4767                 $u->doUpdate();
4768
4769                 if ( $this->getNamespace() == NS_CATEGORY ) {
4770                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4771                         $u->doUpdate();
4772                 }
4773         }
4774
4775         /**
4776          * Get the last touched timestamp
4777          *
4778          * @param DatabaseBase $db Optional db
4779          * @return string Last-touched timestamp
4780          */
4781         public function getTouched( $db = null ) {
4782                 if ( $db === null ) {
4783                         $db = wfGetDB( DB_SLAVE );
4784                 }
4785                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4786                 return $touched;
4787         }
4788
4789         /**
4790          * Get the timestamp when this page was updated since the user last saw it.
4791          *
4792          * @param User $user
4793          * @return string|null
4794          */
4795         public function getNotificationTimestamp( $user = null ) {
4796                 global $wgUser, $wgShowUpdatedMarker;
4797                 // Assume current user if none given
4798                 if ( !$user ) {
4799                         $user = $wgUser;
4800                 }
4801                 // Check cache first
4802                 $uid = $user->getId();
4803                 // avoid isset here, as it'll return false for null entries
4804                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4805                         return $this->mNotificationTimestamp[$uid];
4806                 }
4807                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4808                         $this->mNotificationTimestamp[$uid] = false;
4809                         return $this->mNotificationTimestamp[$uid];
4810                 }
4811                 // Don't cache too much!
4812                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4813                         $this->mNotificationTimestamp = array();
4814                 }
4815                 $dbr = wfGetDB( DB_SLAVE );
4816                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4817                         'wl_notificationtimestamp',
4818                         array(
4819                                 'wl_user' => $user->getId(),
4820                                 'wl_namespace' => $this->getNamespace(),
4821                                 'wl_title' => $this->getDBkey(),
4822                         ),
4823                         __METHOD__
4824                 );
4825                 return $this->mNotificationTimestamp[$uid];
4826         }
4827
4828         /**
4829          * Generate strings used for xml 'id' names in monobook tabs
4830          *
4831          * @param string $prepend Defaults to 'nstab-'
4832          * @return string XML 'id' name
4833          */
4834         public function getNamespaceKey( $prepend = 'nstab-' ) {
4835                 global $wgContLang;
4836                 // Gets the subject namespace if this title
4837                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4838                 // Checks if canonical namespace name exists for namespace
4839                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4840                         // Uses canonical namespace name
4841                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4842                 } else {
4843                         // Uses text of namespace
4844                         $namespaceKey = $this->getSubjectNsText();
4845                 }
4846                 // Makes namespace key lowercase
4847                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4848                 // Uses main
4849                 if ( $namespaceKey == '' ) {
4850                         $namespaceKey = 'main';
4851                 }
4852                 // Changes file to image for backwards compatibility
4853                 if ( $namespaceKey == 'file' ) {
4854                         $namespaceKey = 'image';
4855                 }
4856                 return $prepend . $namespaceKey;
4857         }
4858
4859         /**
4860          * Get all extant redirects to this Title
4861          *
4862          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4863          * @return Title[] Array of Title redirects to this title
4864          */
4865         public function getRedirectsHere( $ns = null ) {
4866                 $redirs = array();
4867
4868                 $dbr = wfGetDB( DB_SLAVE );
4869                 $where = array(
4870                         'rd_namespace' => $this->getNamespace(),
4871                         'rd_title' => $this->getDBkey(),
4872                         'rd_from = page_id'
4873                 );
4874                 if ( $this->isExternal() ) {
4875                         $where['rd_interwiki'] = $this->getInterwiki();
4876                 } else {
4877                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4878                 }
4879                 if ( !is_null( $ns ) ) {
4880                         $where['page_namespace'] = $ns;
4881                 }
4882
4883                 $res = $dbr->select(
4884                         array( 'redirect', 'page' ),
4885                         array( 'page_namespace', 'page_title' ),
4886                         $where,
4887                         __METHOD__
4888                 );
4889
4890                 foreach ( $res as $row ) {
4891                         $redirs[] = self::newFromRow( $row );
4892                 }
4893                 return $redirs;
4894         }
4895
4896         /**
4897          * Check if this Title is a valid redirect target
4898          *
4899          * @return bool
4900          */
4901         public function isValidRedirectTarget() {
4902                 global $wgInvalidRedirectTargets;
4903
4904                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4905                 if ( $this->isSpecial( 'Userlogout' ) ) {
4906                         return false;
4907                 }
4908
4909                 foreach ( $wgInvalidRedirectTargets as $target ) {
4910                         if ( $this->isSpecial( $target ) ) {
4911                                 return false;
4912                         }
4913                 }
4914
4915                 return true;
4916         }
4917
4918         /**
4919          * Get a backlink cache object
4920          *
4921          * @return BacklinkCache
4922          */
4923         public function getBacklinkCache() {
4924                 return BacklinkCache::get( $this );
4925         }
4926
4927         /**
4928          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4929          *
4930          * @return bool
4931          */
4932         public function canUseNoindex() {
4933                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4934
4935                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4936                         ? $wgContentNamespaces
4937                         : $wgExemptFromUserRobotsControl;
4938
4939                 return !in_array( $this->mNamespace, $bannedNamespaces );
4940
4941         }
4942
4943         /**
4944          * Returns the raw sort key to be used for categories, with the specified
4945          * prefix.  This will be fed to Collation::getSortKey() to get a
4946          * binary sortkey that can be used for actual sorting.
4947          *
4948          * @param string $prefix The prefix to be used, specified using
4949          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4950          *   prefix.
4951          * @return string
4952          */
4953         public function getCategorySortkey( $prefix = '' ) {
4954                 $unprefixed = $this->getText();
4955
4956                 // Anything that uses this hook should only depend
4957                 // on the Title object passed in, and should probably
4958                 // tell the users to run updateCollations.php --force
4959                 // in order to re-sort existing category relations.
4960                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4961                 if ( $prefix !== '' ) {
4962                         # Separate with a line feed, so the unprefixed part is only used as
4963                         # a tiebreaker when two pages have the exact same prefix.
4964                         # In UCA, tab is the only character that can sort above LF
4965                         # so we strip both of them from the original prefix.
4966                         $prefix = strtr( $prefix, "\n\t", '  ' );
4967                         return "$prefix\n$unprefixed";
4968                 }
4969                 return $unprefixed;
4970         }
4971
4972         /**
4973          * Get the language in which the content of this page is written in
4974          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4975          * e.g. $wgLang (such as special pages, which are in the user language).
4976          *
4977          * @since 1.18
4978          * @return Language
4979          */
4980         public function getPageLanguage() {
4981                 global $wgLang, $wgLanguageCode;
4982                 wfProfileIn( __METHOD__ );
4983                 if ( $this->isSpecialPage() ) {
4984                         // special pages are in the user language
4985                         wfProfileOut( __METHOD__ );
4986                         return $wgLang;
4987                 }
4988
4989                 // Checking if DB language is set
4990                 if ( $this->mDbPageLanguage ) {
4991                         wfProfileOut( __METHOD__ );
4992                         return wfGetLangObj( $this->mDbPageLanguage );
4993                 }
4994
4995                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4996                         // Note that this may depend on user settings, so the cache should
4997                         // be only per-request.
4998                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4999                         // content to determine the page language!
5000                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
5001                         // tests.
5002                         $contentHandler = ContentHandler::getForTitle( $this );
5003                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
5004                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
5005                 } else {
5006                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
5007                 }
5008
5009                 wfProfileOut( __METHOD__ );
5010                 return $langObj;
5011         }
5012
5013         /**
5014          * Get the language in which the content of this page is written when
5015          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
5016          * e.g. $wgLang (such as special pages, which are in the user language).
5017          *
5018          * @since 1.20
5019          * @return Language
5020          */
5021         public function getPageViewLanguage() {
5022                 global $wgLang;
5023
5024                 if ( $this->isSpecialPage() ) {
5025                         // If the user chooses a variant, the content is actually
5026                         // in a language whose code is the variant code.
5027                         $variant = $wgLang->getPreferredVariant();
5028                         if ( $wgLang->getCode() !== $variant ) {
5029                                 return Language::factory( $variant );
5030                         }
5031
5032                         return $wgLang;
5033                 }
5034
5035                 // @note Can't be cached persistently, depends on user settings.
5036                 // @note ContentHandler::getPageViewLanguage() may need to load the
5037                 //   content to determine the page language!
5038                 $contentHandler = ContentHandler::getForTitle( $this );
5039                 $pageLang = $contentHandler->getPageViewLanguage( $this );
5040                 return $pageLang;
5041         }
5042
5043         /**
5044          * Get a list of rendered edit notices for this page.
5045          *
5046          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
5047          * they will already be wrapped in paragraphs.
5048          *
5049          * @since 1.21
5050          * @param int $oldid Revision ID that's being edited
5051          * @return array
5052          */
5053         public function getEditNotices( $oldid = 0 ) {
5054                 $notices = array();
5055
5056                 # Optional notices on a per-namespace and per-page basis
5057                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
5058                 $editnotice_ns_message = wfMessage( $editnotice_ns );
5059                 if ( $editnotice_ns_message->exists() ) {
5060                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
5061                 }
5062                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
5063                         $parts = explode( '/', $this->getDBkey() );
5064                         $editnotice_base = $editnotice_ns;
5065                         while ( count( $parts ) > 0 ) {
5066                                 $editnotice_base .= '-' . array_shift( $parts );
5067                                 $editnotice_base_msg = wfMessage( $editnotice_base );
5068                                 if ( $editnotice_base_msg->exists() ) {
5069                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
5070                                 }
5071                         }
5072                 } else {
5073                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
5074                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
5075                         $editnoticeMsg = wfMessage( $editnoticeText );
5076                         if ( $editnoticeMsg->exists() ) {
5077                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
5078                         }
5079                 }
5080
5081                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
5082                 return $notices;
5083         }
5084 }