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          */
1375         private function prefix( $name ) {
1376                 $p = '';
1377                 if ( $this->isExternal() ) {
1378                         $p = $this->mInterwiki . ':';
1379                 }
1380
1381                 if ( 0 != $this->mNamespace ) {
1382                         $p .= $this->getNsText() . ':';
1383                 }
1384                 return $p . $name;
1385         }
1386
1387         /**
1388          * Get the prefixed database key form
1389          *
1390          * @return string The prefixed title, with underscores and
1391          *  any interwiki and namespace prefixes
1392          */
1393         public function getPrefixedDBkey() {
1394                 $s = $this->prefix( $this->mDbkeyform );
1395                 $s = str_replace( ' ', '_', $s );
1396                 return $s;
1397         }
1398
1399         /**
1400          * Get the prefixed title with spaces.
1401          * This is the form usually used for display
1402          *
1403          * @return string The prefixed title, with spaces
1404          */
1405         public function getPrefixedText() {
1406                 if ( $this->mPrefixedText === null ) {
1407                         $s = $this->prefix( $this->mTextform );
1408                         $s = str_replace( '_', ' ', $s );
1409                         $this->mPrefixedText = $s;
1410                 }
1411                 return $this->mPrefixedText;
1412         }
1413
1414         /**
1415          * Return a string representation of this title
1416          *
1417          * @return string Representation of this title
1418          */
1419         public function __toString() {
1420                 return $this->getPrefixedText();
1421         }
1422
1423         /**
1424          * Get the prefixed title with spaces, plus any fragment
1425          * (part beginning with '#')
1426          *
1427          * @return string The prefixed title, with spaces and the fragment, including '#'
1428          */
1429         public function getFullText() {
1430                 $text = $this->getPrefixedText();
1431                 if ( $this->hasFragment() ) {
1432                         $text .= '#' . $this->getFragment();
1433                 }
1434                 return $text;
1435         }
1436
1437         /**
1438          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1439          *
1440          * @par Example:
1441          * @code
1442          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1443          * # returns: 'Foo'
1444          * @endcode
1445          *
1446          * @return string Root name
1447          * @since 1.20
1448          */
1449         public function getRootText() {
1450                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1451                         return $this->getText();
1452                 }
1453
1454                 return strtok( $this->getText(), '/' );
1455         }
1456
1457         /**
1458          * Get the root page name title, i.e. the leftmost part before any slashes
1459          *
1460          * @par Example:
1461          * @code
1462          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1463          * # returns: Title{User:Foo}
1464          * @endcode
1465          *
1466          * @return Title Root title
1467          * @since 1.20
1468          */
1469         public function getRootTitle() {
1470                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1471         }
1472
1473         /**
1474          * Get the base page name without a namespace, i.e. the part before the subpage name
1475          *
1476          * @par Example:
1477          * @code
1478          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1479          * # returns: 'Foo/Bar'
1480          * @endcode
1481          *
1482          * @return string Base name
1483          */
1484         public function getBaseText() {
1485                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1486                         return $this->getText();
1487                 }
1488
1489                 $parts = explode( '/', $this->getText() );
1490                 # Don't discard the real title if there's no subpage involved
1491                 if ( count( $parts ) > 1 ) {
1492                         unset( $parts[count( $parts ) - 1] );
1493                 }
1494                 return implode( '/', $parts );
1495         }
1496
1497         /**
1498          * Get the base page name title, i.e. the part before the subpage name
1499          *
1500          * @par Example:
1501          * @code
1502          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1503          * # returns: Title{User:Foo/Bar}
1504          * @endcode
1505          *
1506          * @return Title Base title
1507          * @since 1.20
1508          */
1509         public function getBaseTitle() {
1510                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1511         }
1512
1513         /**
1514          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1515          *
1516          * @par Example:
1517          * @code
1518          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1519          * # returns: "Baz"
1520          * @endcode
1521          *
1522          * @return string Subpage name
1523          */
1524         public function getSubpageText() {
1525                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1526                         return $this->mTextform;
1527                 }
1528                 $parts = explode( '/', $this->mTextform );
1529                 return $parts[count( $parts ) - 1];
1530         }
1531
1532         /**
1533          * Get the title for a subpage of the current page
1534          *
1535          * @par Example:
1536          * @code
1537          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1538          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1539          * @endcode
1540          *
1541          * @param string $text The subpage name to add to the title
1542          * @return Title Subpage title
1543          * @since 1.20
1544          */
1545         public function getSubpage( $text ) {
1546                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1547         }
1548
1549         /**
1550          * Get the HTML-escaped displayable text form.
1551          * Used for the title field in <a> tags.
1552          *
1553          * @return string The text, including any prefixes
1554          * @deprecated since 1.19
1555          */
1556         public function getEscapedText() {
1557                 wfDeprecated( __METHOD__, '1.19' );
1558                 return htmlspecialchars( $this->getPrefixedText() );
1559         }
1560
1561         /**
1562          * Get a URL-encoded form of the subpage text
1563          *
1564          * @return string URL-encoded subpage name
1565          */
1566         public function getSubpageUrlForm() {
1567                 $text = $this->getSubpageText();
1568                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1569                 return $text;
1570         }
1571
1572         /**
1573          * Get a URL-encoded title (not an actual URL) including interwiki
1574          *
1575          * @return string The URL-encoded form
1576          */
1577         public function getPrefixedURL() {
1578                 $s = $this->prefix( $this->mDbkeyform );
1579                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1580                 return $s;
1581         }
1582
1583         /**
1584          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1585          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1586          * second argument named variant. This was deprecated in favor
1587          * of passing an array of option with a "variant" key
1588          * Once $query2 is removed for good, this helper can be dropped
1589          * and the wfArrayToCgi moved to getLocalURL();
1590          *
1591          * @since 1.19 (r105919)
1592          * @param array|string $query
1593          * @param bool $query2
1594          * @return string
1595          */
1596         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1597                 if ( $query2 !== false ) {
1598                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1599                                 "method called with a second parameter is deprecated. Add your " .
1600                                 "parameter to an array passed as the first parameter.", "1.19" );
1601                 }
1602                 if ( is_array( $query ) ) {
1603                         $query = wfArrayToCgi( $query );
1604                 }
1605                 if ( $query2 ) {
1606                         if ( is_string( $query2 ) ) {
1607                                 // $query2 is a string, we will consider this to be
1608                                 // a deprecated $variant argument and add it to the query
1609                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1610                         } else {
1611                                 $query2 = wfArrayToCgi( $query2 );
1612                         }
1613                         // If we have $query content add a & to it first
1614                         if ( $query ) {
1615                                 $query .= '&';
1616                         }
1617                         // Now append the queries together
1618                         $query .= $query2;
1619                 }
1620                 return $query;
1621         }
1622
1623         /**
1624          * Get a real URL referring to this title, with interwiki link and
1625          * fragment
1626          *
1627          * @see self::getLocalURL for the arguments.
1628          * @see wfExpandUrl
1629          * @param array|string $query
1630          * @param bool $query2
1631          * @param string $proto Protocol type to use in URL
1632          * @return string The URL
1633          */
1634         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1635                 $query = self::fixUrlQueryArgs( $query, $query2 );
1636
1637                 # Hand off all the decisions on urls to getLocalURL
1638                 $url = $this->getLocalURL( $query );
1639
1640                 # Expand the url to make it a full url. Note that getLocalURL has the
1641                 # potential to output full urls for a variety of reasons, so we use
1642                 # wfExpandUrl instead of simply prepending $wgServer
1643                 $url = wfExpandUrl( $url, $proto );
1644
1645                 # Finally, add the fragment.
1646                 $url .= $this->getFragmentForURL();
1647
1648                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1649                 return $url;
1650         }
1651
1652         /**
1653          * Get a URL with no fragment or server name (relative URL) from a Title object.
1654          * If this page is generated with action=render, however,
1655          * $wgServer is prepended to make an absolute URL.
1656          *
1657          * @see self::getFullURL to always get an absolute URL.
1658          * @see self::newFromText to produce a Title object.
1659          *
1660          * @param string|array $query an optional query string,
1661          *   not used for interwiki links. Can be specified as an associative array as well,
1662          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1663          *   Some query patterns will trigger various shorturl path replacements.
1664          * @param array $query2 An optional secondary query array. This one MUST
1665          *   be an array. If a string is passed it will be interpreted as a deprecated
1666          *   variant argument and urlencoded into a variant= argument.
1667          *   This second query argument will be added to the $query
1668          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1669          *   pair in the first parameter array instead.
1670          *
1671          * @return string String of the URL.
1672          */
1673         public function getLocalURL( $query = '', $query2 = false ) {
1674                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1675
1676                 $query = self::fixUrlQueryArgs( $query, $query2 );
1677
1678                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1679                 if ( $interwiki ) {
1680                         $namespace = $this->getNsText();
1681                         if ( $namespace != '' ) {
1682                                 # Can this actually happen? Interwikis shouldn't be parsed.
1683                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1684                                 $namespace .= ':';
1685                         }
1686                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1687                         $url = wfAppendQuery( $url, $query );
1688                 } else {
1689                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1690                         if ( $query == '' ) {
1691                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1692                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1693                         } else {
1694                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1695                                 $url = false;
1696                                 $matches = array();
1697
1698                                 if ( !empty( $wgActionPaths )
1699                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1700                                 ) {
1701                                         $action = urldecode( $matches[2] );
1702                                         if ( isset( $wgActionPaths[$action] ) ) {
1703                                                 $query = $matches[1];
1704                                                 if ( isset( $matches[4] ) ) {
1705                                                         $query .= $matches[4];
1706                                                 }
1707                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1708                                                 if ( $query != '' ) {
1709                                                         $url = wfAppendQuery( $url, $query );
1710                                                 }
1711                                         }
1712                                 }
1713
1714                                 if ( $url === false
1715                                         && $wgVariantArticlePath
1716                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1717                                         && $this->getPageLanguage()->hasVariants()
1718                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1719                                 ) {
1720                                         $variant = urldecode( $matches[1] );
1721                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1722                                                 // Only do the variant replacement if the given variant is a valid
1723                                                 // variant for the page's language.
1724                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1725                                                 $url = str_replace( '$1', $dbkey, $url );
1726                                         }
1727                                 }
1728
1729                                 if ( $url === false ) {
1730                                         if ( $query == '-' ) {
1731                                                 $query = '';
1732                                         }
1733                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1734                                 }
1735                         }
1736
1737                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1738
1739                         // @todo FIXME: This causes breakage in various places when we
1740                         // actually expected a local URL and end up with dupe prefixes.
1741                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1742                                 $url = $wgServer . $url;
1743                         }
1744                 }
1745                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1746                 return $url;
1747         }
1748
1749         /**
1750          * Get a URL that's the simplest URL that will be valid to link, locally,
1751          * to the current Title.  It includes the fragment, but does not include
1752          * the server unless action=render is used (or the link is external).  If
1753          * there's a fragment but the prefixed text is empty, we just return a link
1754          * to the fragment.
1755          *
1756          * The result obviously should not be URL-escaped, but does need to be
1757          * HTML-escaped if it's being output in HTML.
1758          *
1759          * @param array $query
1760          * @param bool $query2
1761          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1762          * @see self::getLocalURL for the arguments.
1763          * @return string The URL
1764          */
1765         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1766                 wfProfileIn( __METHOD__ );
1767                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1768                         $ret = $this->getFullURL( $query, $query2, $proto );
1769                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1770                         $ret = $this->getFragmentForURL();
1771                 } else {
1772                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1773                 }
1774                 wfProfileOut( __METHOD__ );
1775                 return $ret;
1776         }
1777
1778         /**
1779          * Get an HTML-escaped version of the URL form, suitable for
1780          * using in a link, without a server name or fragment
1781          *
1782          * @see self::getLocalURL for the arguments.
1783          * @param string $query
1784          * @param bool|string $query2
1785          * @return string The URL
1786          * @deprecated since 1.19
1787          */
1788         public function escapeLocalURL( $query = '', $query2 = false ) {
1789                 wfDeprecated( __METHOD__, '1.19' );
1790                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1791         }
1792
1793         /**
1794          * Get an HTML-escaped version of the URL form, suitable for
1795          * using in a link, including the server name and fragment
1796          *
1797          * @see self::getLocalURL for the arguments.
1798          * @return string The URL
1799          * @deprecated since 1.19
1800          */
1801         public function escapeFullURL( $query = '', $query2 = false ) {
1802                 wfDeprecated( __METHOD__, '1.19' );
1803                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1804         }
1805
1806         /**
1807          * Get the URL form for an internal link.
1808          * - Used in various Squid-related code, in case we have a different
1809          * internal hostname for the server from the exposed one.
1810          *
1811          * This uses $wgInternalServer to qualify the path, or $wgServer
1812          * if $wgInternalServer is not set. If the server variable used is
1813          * protocol-relative, the URL will be expanded to http://
1814          *
1815          * @see self::getLocalURL for the arguments.
1816          * @return string The URL
1817          */
1818         public function getInternalURL( $query = '', $query2 = false ) {
1819                 global $wgInternalServer, $wgServer;
1820                 $query = self::fixUrlQueryArgs( $query, $query2 );
1821                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1822                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1823                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1824                 return $url;
1825         }
1826
1827         /**
1828          * Get the URL for a canonical link, for use in things like IRC and
1829          * e-mail notifications. Uses $wgCanonicalServer and the
1830          * GetCanonicalURL hook.
1831          *
1832          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1833          *
1834          * @see self::getLocalURL for the arguments.
1835          * @return string The URL
1836          * @since 1.18
1837          */
1838         public function getCanonicalURL( $query = '', $query2 = false ) {
1839                 $query = self::fixUrlQueryArgs( $query, $query2 );
1840                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1841                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1842                 return $url;
1843         }
1844
1845         /**
1846          * HTML-escaped version of getCanonicalURL()
1847          *
1848          * @see self::getLocalURL for the arguments.
1849          * @since 1.18
1850          * @return string
1851          * @deprecated since 1.19
1852          */
1853         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1854                 wfDeprecated( __METHOD__, '1.19' );
1855                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1856         }
1857
1858         /**
1859          * Get the edit URL for this Title
1860          *
1861          * @return string The URL, or a null string if this is an interwiki link
1862          */
1863         public function getEditURL() {
1864                 if ( $this->isExternal() ) {
1865                         return '';
1866                 }
1867                 $s = $this->getLocalURL( 'action=edit' );
1868
1869                 return $s;
1870         }
1871
1872         /**
1873          * Is $wgUser watching this page?
1874          *
1875          * @deprecated since 1.20; use User::isWatched() instead.
1876          * @return bool
1877          */
1878         public function userIsWatching() {
1879                 global $wgUser;
1880
1881                 if ( is_null( $this->mWatched ) ) {
1882                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1883                                 $this->mWatched = false;
1884                         } else {
1885                                 $this->mWatched = $wgUser->isWatched( $this );
1886                         }
1887                 }
1888                 return $this->mWatched;
1889         }
1890
1891         /**
1892          * Can $wgUser read this page?
1893          *
1894          * @deprecated since 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1895          * @return bool
1896          */
1897         public function userCanRead() {
1898                 wfDeprecated( __METHOD__, '1.19' );
1899                 return $this->userCan( 'read' );
1900         }
1901
1902         /**
1903          * Can $user perform $action on this page?
1904          * This skips potentially expensive cascading permission checks
1905          * as well as avoids expensive error formatting
1906          *
1907          * Suitable for use for nonessential UI controls in common cases, but
1908          * _not_ for functional access control.
1909          *
1910          * May provide false positives, but should never provide a false negative.
1911          *
1912          * @param string $action Action that permission needs to be checked for
1913          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1914          * @return bool
1915          */
1916         public function quickUserCan( $action, $user = null ) {
1917                 return $this->userCan( $action, $user, false );
1918         }
1919
1920         /**
1921          * Can $user perform $action on this page?
1922          *
1923          * @param string $action Action that permission needs to be checked for
1924          * @param User $user User to check (since 1.19); $wgUser will be used if not
1925          *   provided.
1926          * @param bool $doExpensiveQueries Set this to false to avoid doing
1927          *   unnecessary queries.
1928          * @return bool
1929          */
1930         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1931                 if ( !$user instanceof User ) {
1932                         global $wgUser;
1933                         $user = $wgUser;
1934                 }
1935
1936                 return !count( $this->getUserPermissionsErrorsInternal(
1937                         $action, $user, $doExpensiveQueries, true ) );
1938         }
1939
1940         /**
1941          * Can $user perform $action on this page?
1942          *
1943          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1944          *
1945          * @param string $action action that permission needs to be checked for
1946          * @param User $user User to check
1947          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1948          *   queries by skipping checks for cascading protections and user blocks.
1949          * @param array $ignoreErrors of Strings Set this to a list of message keys
1950          *   whose corresponding errors may be ignored.
1951          * @return array Array of arguments to wfMessage to explain permissions problems.
1952          */
1953         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true,
1954                 $ignoreErrors = array()
1955         ) {
1956                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1957
1958                 // Remove the errors being ignored.
1959                 foreach ( $errors as $index => $error ) {
1960                         $error_key = is_array( $error ) ? $error[0] : $error;
1961
1962                         if ( in_array( $error_key, $ignoreErrors ) ) {
1963                                 unset( $errors[$index] );
1964                         }
1965                 }
1966
1967                 return $errors;
1968         }
1969
1970         /**
1971          * Permissions checks that fail most often, and which are easiest to test.
1972          *
1973          * @param string $action the action to check
1974          * @param User $user User to check
1975          * @param array $errors List of current errors
1976          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
1977          * @param bool $short Short circuit on first error
1978          *
1979          * @return array List of errors
1980          */
1981         private function checkQuickPermissions( $action, $user, $errors,
1982                 $doExpensiveQueries, $short
1983         ) {
1984                 if ( !wfRunHooks( 'TitleQuickPermissions',
1985                         array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) )
1986                 ) {
1987                         return $errors;
1988                 }
1989
1990                 if ( $action == 'create' ) {
1991                         if (
1992                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1993                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1994                         ) {
1995                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1996                         }
1997                 } elseif ( $action == 'move' ) {
1998                         if ( !$user->isAllowed( 'move-rootuserpages' )
1999                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2000                                 // Show user page-specific message only if the user can move other pages
2001                                 $errors[] = array( 'cant-move-user-page' );
2002                         }
2003
2004                         // Check if user is allowed to move files if it's a file
2005                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2006                                 $errors[] = array( 'movenotallowedfile' );
2007                         }
2008
2009                         // Check if user is allowed to move category pages if it's a category page
2010                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2011                                 $errors[] = array( 'cant-move-category-page' );
2012                         }
2013
2014                         if ( !$user->isAllowed( 'move' ) ) {
2015                                 // User can't move anything
2016                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2017                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2018                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2019                                         // custom message if logged-in users without any special rights can move
2020                                         $errors[] = array( 'movenologintext' );
2021                                 } else {
2022                                         $errors[] = array( 'movenotallowed' );
2023                                 }
2024                         }
2025                 } elseif ( $action == 'move-target' ) {
2026                         if ( !$user->isAllowed( 'move' ) ) {
2027                                 // User can't move anything
2028                                 $errors[] = array( 'movenotallowed' );
2029                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2030                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2031                                 // Show user page-specific message only if the user can move other pages
2032                                 $errors[] = array( 'cant-move-to-user-page' );
2033                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2034                                         && $this->mNamespace == NS_CATEGORY ) {
2035                                 // Show category page-specific message only if the user can move other pages
2036                                 $errors[] = array( 'cant-move-to-category-page' );
2037                         }
2038                 } elseif ( !$user->isAllowed( $action ) ) {
2039                         $errors[] = $this->missingPermissionError( $action, $short );
2040                 }
2041
2042                 return $errors;
2043         }
2044
2045         /**
2046          * Add the resulting error code to the errors array
2047          *
2048          * @param array $errors List of current errors
2049          * @param array $result Result of errors
2050          *
2051          * @return array List of errors
2052          */
2053         private function resultToError( $errors, $result ) {
2054                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2055                         // A single array representing an error
2056                         $errors[] = $result;
2057                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2058                         // A nested array representing multiple errors
2059                         $errors = array_merge( $errors, $result );
2060                 } elseif ( $result !== '' && is_string( $result ) ) {
2061                         // A string representing a message-id
2062                         $errors[] = array( $result );
2063                 } elseif ( $result === false ) {
2064                         // a generic "We don't want them to do that"
2065                         $errors[] = array( 'badaccess-group0' );
2066                 }
2067                 return $errors;
2068         }
2069
2070         /**
2071          * Check various permission hooks
2072          *
2073          * @param string $action The action to check
2074          * @param User $user User to check
2075          * @param array $errors List of current errors
2076          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2077          * @param bool $short Short circuit on first error
2078          *
2079          * @return array List of errors
2080          */
2081         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
2082                 // Use getUserPermissionsErrors instead
2083                 $result = '';
2084                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2085                         return $result ? array() : array( array( 'badaccess-group0' ) );
2086                 }
2087                 // Check getUserPermissionsErrors hook
2088                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2089                         $errors = $this->resultToError( $errors, $result );
2090                 }
2091                 // Check getUserPermissionsErrorsExpensive hook
2092                 if (
2093                         $doExpensiveQueries
2094                         && !( $short && count( $errors ) > 0 )
2095                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2096                 ) {
2097                         $errors = $this->resultToError( $errors, $result );
2098                 }
2099
2100                 return $errors;
2101         }
2102
2103         /**
2104          * Check permissions on special pages & namespaces
2105          *
2106          * @param string $action The action to check
2107          * @param User $user User to check
2108          * @param array $errors List of current errors
2109          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2110          * @param bool $short Short circuit on first error
2111          *
2112          * @return array List of errors
2113          */
2114         private function checkSpecialsAndNSPermissions( $action, $user, $errors,
2115                 $doExpensiveQueries, $short
2116         ) {
2117                 # Only 'createaccount' can be performed on special pages,
2118                 # which don't actually exist in the DB.
2119                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2120                         $errors[] = array( 'ns-specialprotected' );
2121                 }
2122
2123                 # Check $wgNamespaceProtection for restricted namespaces
2124                 if ( $this->isNamespaceProtected( $user ) ) {
2125                         $ns = $this->mNamespace == NS_MAIN ?
2126                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2127                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2128                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
2129                 }
2130
2131                 return $errors;
2132         }
2133
2134         /**
2135          * Check CSS/JS sub-page permissions
2136          *
2137          * @param string $action The action to check
2138          * @param User $user User to check
2139          * @param array $errors List of current errors
2140          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2141          * @param bool $short Short circuit on first error
2142          *
2143          * @return array List of errors
2144          */
2145         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2146                 # Protect css/js subpages of user pages
2147                 # XXX: this might be better using restrictions
2148                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2149                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2150                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2151                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2152                                         $errors[] = array( 'mycustomcssprotected' );
2153                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2154                                         $errors[] = array( 'mycustomjsprotected' );
2155                                 }
2156                         } else {
2157                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2158                                         $errors[] = array( 'customcssprotected' );
2159                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2160                                         $errors[] = array( 'customjsprotected' );
2161                                 }
2162                         }
2163                 }
2164
2165                 return $errors;
2166         }
2167
2168         /**
2169          * Check against page_restrictions table requirements on this
2170          * page. The user must possess all required rights for this
2171          * action.
2172          *
2173          * @param string $action The action to check
2174          * @param User $user User to check
2175          * @param array $errors List of current errors
2176          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2177          * @param bool $short Short circuit on first error
2178          *
2179          * @return array List of errors
2180          */
2181         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2182                 foreach ( $this->getRestrictions( $action ) as $right ) {
2183                         // Backwards compatibility, rewrite sysop -> editprotected
2184                         if ( $right == 'sysop' ) {
2185                                 $right = 'editprotected';
2186                         }
2187                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2188                         if ( $right == 'autoconfirmed' ) {
2189                                 $right = 'editsemiprotected';
2190                         }
2191                         if ( $right == '' ) {
2192                                 continue;
2193                         }
2194                         if ( !$user->isAllowed( $right ) ) {
2195                                 $errors[] = array( 'protectedpagetext', $right );
2196                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2197                                 $errors[] = array( 'protectedpagetext', 'protect' );
2198                         }
2199                 }
2200
2201                 return $errors;
2202         }
2203
2204         /**
2205          * Check restrictions on cascading pages.
2206          *
2207          * @param string $action The action to check
2208          * @param User $user User to check
2209          * @param array $errors List of current errors
2210          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2211          * @param bool $short Short circuit on first error
2212          *
2213          * @return array List of errors
2214          */
2215         private function checkCascadingSourcesRestrictions( $action, $user, $errors,
2216                 $doExpensiveQueries, $short
2217         ) {
2218                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2219                         # We /could/ use the protection level on the source page, but it's
2220                         # fairly ugly as we have to establish a precedence hierarchy for pages
2221                         # included by multiple cascade-protected pages. So just restrict
2222                         # it to people with 'protect' permission, as they could remove the
2223                         # protection anyway.
2224                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2225                         # Cascading protection depends on more than this page...
2226                         # Several cascading protected pages may include this page...
2227                         # Check each cascading level
2228                         # This is only for protection restrictions, not for all actions
2229                         if ( isset( $restrictions[$action] ) ) {
2230                                 foreach ( $restrictions[$action] as $right ) {
2231                                         // Backwards compatibility, rewrite sysop -> editprotected
2232                                         if ( $right == 'sysop' ) {
2233                                                 $right = 'editprotected';
2234                                         }
2235                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2236                                         if ( $right == 'autoconfirmed' ) {
2237                                                 $right = 'editsemiprotected';
2238                                         }
2239                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2240                                                 $pages = '';
2241                                                 foreach ( $cascadingSources as $page ) {
2242                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2243                                                 }
2244                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2245                                         }
2246                                 }
2247                         }
2248                 }
2249
2250                 return $errors;
2251         }
2252
2253         /**
2254          * Check action permissions not already checked in checkQuickPermissions
2255          *
2256          * @param string $action The action to check
2257          * @param User $user User to check
2258          * @param array $errors List of current errors
2259          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2260          * @param bool $short Short circuit on first error
2261          *
2262          * @return array List of errors
2263          */
2264         private function checkActionPermissions( $action, $user, $errors,
2265                 $doExpensiveQueries, $short
2266         ) {
2267                 global $wgDeleteRevisionsLimit, $wgLang;
2268
2269                 if ( $action == 'protect' ) {
2270                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit',
2271                                 $user, $doExpensiveQueries, true ) )
2272                         ) {
2273                                 // If they can't edit, they shouldn't protect.
2274                                 $errors[] = array( 'protect-cantedit' );
2275                         }
2276                 } elseif ( $action == 'create' ) {
2277                         $title_protection = $this->getTitleProtection();
2278                         if ( $title_protection ) {
2279                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2280                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2281                                 }
2282                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2283                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2284                                 }
2285                                 if ( $title_protection['pt_create_perm'] == ''
2286                                         || !$user->isAllowed( $title_protection['pt_create_perm'] )
2287                                 ) {
2288                                         $errors[] = array(
2289                                                 'titleprotected',
2290                                                 User::whoIs( $title_protection['pt_user'] ),
2291                                                 $title_protection['pt_reason']
2292                                         );
2293                                 }
2294                         }
2295                 } elseif ( $action == 'move' ) {
2296                         // Check for immobile pages
2297                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2298                                 // Specific message for this case
2299                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2300                         } elseif ( !$this->isMovable() ) {
2301                                 // Less specific message for rarer cases
2302                                 $errors[] = array( 'immobile-source-page' );
2303                         }
2304                 } elseif ( $action == 'move-target' ) {
2305                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2306                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2307                         } elseif ( !$this->isMovable() ) {
2308                                 $errors[] = array( 'immobile-target-page' );
2309                         }
2310                 } elseif ( $action == 'delete' ) {
2311                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2312                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2313                         ) {
2314                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2315                         }
2316                 }
2317                 return $errors;
2318         }
2319
2320         /**
2321          * Check that the user isn't blocked from editing.
2322          *
2323          * @param string $action The action to check
2324          * @param User $user User to check
2325          * @param array $errors List of current errors
2326          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2327          * @param bool $short Short circuit on first error
2328          *
2329          * @return array List of errors
2330          */
2331         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2332                 // Account creation blocks handled at userlogin.
2333                 // Unblocking handled in SpecialUnblock
2334                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2335                         return $errors;
2336                 }
2337
2338                 global $wgEmailConfirmToEdit;
2339
2340                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2341                         $errors[] = array( 'confirmedittext' );
2342                 }
2343
2344                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2345                         // Don't block the user from editing their own talk page unless they've been
2346                         // explicitly blocked from that too.
2347                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2348                         // @todo FIXME: Pass the relevant context into this function.
2349                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2350                 }
2351
2352                 return $errors;
2353         }
2354
2355         /**
2356          * Check that the user is allowed to read this page.
2357          *
2358          * @param string $action The action to check
2359          * @param User $user User to check
2360          * @param array $errors List of current errors
2361          * @param bool $doExpensiveQueries Whether or not to perform expensive queries
2362          * @param bool $short Short circuit on first error
2363          *
2364          * @return array List of errors
2365          */
2366         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2367                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2368
2369                 $whitelisted = false;
2370                 if ( User::isEveryoneAllowed( 'read' ) ) {
2371                         # Shortcut for public wikis, allows skipping quite a bit of code
2372                         $whitelisted = true;
2373                 } elseif ( $user->isAllowed( 'read' ) ) {
2374                         # If the user is allowed to read pages, he is allowed to read all pages
2375                         $whitelisted = true;
2376                 } elseif ( $this->isSpecial( 'Userlogin' )
2377                         || $this->isSpecial( 'ChangePassword' )
2378                         || $this->isSpecial( 'PasswordReset' )
2379                 ) {
2380                         # Always grant access to the login page.
2381                         # Even anons need to be able to log in.
2382                         $whitelisted = true;
2383                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2384                         # Time to check the whitelist
2385                         # Only do these checks is there's something to check against
2386                         $name = $this->getPrefixedText();
2387                         $dbName = $this->getPrefixedDBkey();
2388
2389                         // Check for explicit whitelisting with and without underscores
2390                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2391                                 $whitelisted = true;
2392                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2393                                 # Old settings might have the title prefixed with
2394                                 # a colon for main-namespace pages
2395                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2396                                         $whitelisted = true;
2397                                 }
2398                         } elseif ( $this->isSpecialPage() ) {
2399                                 # If it's a special page, ditch the subpage bit and check again
2400                                 $name = $this->getDBkey();
2401                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2402                                 if ( $name ) {
2403                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2404                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2405                                                 $whitelisted = true;
2406                                         }
2407                                 }
2408                         }
2409                 }
2410
2411                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2412                         $name = $this->getPrefixedText();
2413                         // Check for regex whitelisting
2414                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2415                                 if ( preg_match( $listItem, $name ) ) {
2416                                         $whitelisted = true;
2417                                         break;
2418                                 }
2419                         }
2420                 }
2421
2422                 if ( !$whitelisted ) {
2423                         # If the title is not whitelisted, give extensions a chance to do so...
2424                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2425                         if ( !$whitelisted ) {
2426                                 $errors[] = $this->missingPermissionError( $action, $short );
2427                         }
2428                 }
2429
2430                 return $errors;
2431         }
2432
2433         /**
2434          * Get a description array when the user doesn't have the right to perform
2435          * $action (i.e. when User::isAllowed() returns false)
2436          *
2437          * @param string $action The action to check
2438          * @param bool $short Short circuit on first error
2439          * @return array List of errors
2440          */
2441         private function missingPermissionError( $action, $short ) {
2442                 // We avoid expensive display logic for quickUserCan's and such
2443                 if ( $short ) {
2444                         return array( 'badaccess-group0' );
2445                 }
2446
2447                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2448                         User::getGroupsWithPermission( $action ) );
2449
2450                 if ( count( $groups ) ) {
2451                         global $wgLang;
2452                         return array(
2453                                 'badaccess-groups',
2454                                 $wgLang->commaList( $groups ),
2455                                 count( $groups )
2456                         );
2457                 } else {
2458                         return array( 'badaccess-group0' );
2459                 }
2460         }
2461
2462         /**
2463          * Can $user perform $action on this page? This is an internal function,
2464          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2465          * checks on wfReadOnly() and blocks)
2466          *
2467          * @param string $action Action that permission needs to be checked for
2468          * @param User $user User to check
2469          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2470          * @param bool $short Set this to true to stop after the first permission error.
2471          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2472          */
2473         protected function getUserPermissionsErrorsInternal( $action, $user,
2474                 $doExpensiveQueries = true, $short = false
2475         ) {
2476                 wfProfileIn( __METHOD__ );
2477
2478                 # Read has special handling
2479                 if ( $action == 'read' ) {
2480                         $checks = array(
2481                                 'checkPermissionHooks',
2482                                 'checkReadPermissions',
2483                         );
2484                 } else {
2485                         $checks = array(
2486                                 'checkQuickPermissions',
2487                                 'checkPermissionHooks',
2488                                 'checkSpecialsAndNSPermissions',
2489                                 'checkCSSandJSPermissions',
2490                                 'checkPageRestrictions',
2491                                 'checkCascadingSourcesRestrictions',
2492                                 'checkActionPermissions',
2493                                 'checkUserBlock'
2494                         );
2495                 }
2496
2497                 $errors = array();
2498                 while ( count( $checks ) > 0 &&
2499                                 !( $short && count( $errors ) > 0 ) ) {
2500                         $method = array_shift( $checks );
2501                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2502                 }
2503
2504                 wfProfileOut( __METHOD__ );
2505                 return $errors;
2506         }
2507
2508         /**
2509          * Get a filtered list of all restriction types supported by this wiki.
2510          * @param bool $exists True to get all restriction types that apply to
2511          * titles that do exist, False for all restriction types that apply to
2512          * titles that do not exist
2513          * @return array
2514          */
2515         public static function getFilteredRestrictionTypes( $exists = true ) {
2516                 global $wgRestrictionTypes;
2517                 $types = $wgRestrictionTypes;
2518                 if ( $exists ) {
2519                         # Remove the create restriction for existing titles
2520                         $types = array_diff( $types, array( 'create' ) );
2521                 } else {
2522                         # Only the create and upload restrictions apply to non-existing titles
2523                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2524                 }
2525                 return $types;
2526         }
2527
2528         /**
2529          * Returns restriction types for the current Title
2530          *
2531          * @return array Applicable restriction types
2532          */
2533         public function getRestrictionTypes() {
2534                 if ( $this->isSpecialPage() ) {
2535                         return array();
2536                 }
2537
2538                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2539
2540                 if ( $this->getNamespace() != NS_FILE ) {
2541                         # Remove the upload restriction for non-file titles
2542                         $types = array_diff( $types, array( 'upload' ) );
2543                 }
2544
2545                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2546
2547                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2548                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2549
2550                 return $types;
2551         }
2552
2553         /**
2554          * Is this title subject to title protection?
2555          * Title protection is the one applied against creation of such title.
2556          *
2557          * @return array|bool An associative array representing any existent title
2558          *   protection, or false if there's none.
2559          */
2560         private function getTitleProtection() {
2561                 // Can't protect pages in special namespaces
2562                 if ( $this->getNamespace() < 0 ) {
2563                         return false;
2564                 }
2565
2566                 // Can't protect pages that exist.
2567                 if ( $this->exists() ) {
2568                         return false;
2569                 }
2570
2571                 if ( $this->mTitleProtection === null ) {
2572                         $dbr = wfGetDB( DB_SLAVE );
2573                         $res = $dbr->select(
2574                                 'protected_titles',
2575                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2576                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2577                                 __METHOD__
2578                         );
2579
2580                         // fetchRow returns false if there are no rows.
2581                         $this->mTitleProtection = $dbr->fetchRow( $res );
2582                 }
2583                 return $this->mTitleProtection;
2584         }
2585
2586         /**
2587          * Update the title protection status
2588          *
2589          * @deprecated since 1.19; use WikiPage::doUpdateRestrictions() instead.
2590          * @param string $create_perm Permission required for creation
2591          * @param string $reason Reason for protection
2592          * @param string $expiry Expiry timestamp
2593          * @return bool
2594          */
2595         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2596                 wfDeprecated( __METHOD__, '1.19' );
2597
2598                 global $wgUser;
2599
2600                 $limit = array( 'create' => $create_perm );
2601                 $expiry = array( 'create' => $expiry );
2602
2603                 $page = WikiPage::factory( $this );
2604                 $cascade = false;
2605                 $status = $page->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $wgUser );
2606
2607                 return $status->isOK();
2608         }
2609
2610         /**
2611          * Remove any title protection due to page existing
2612          */
2613         public function deleteTitleProtection() {
2614                 $dbw = wfGetDB( DB_MASTER );
2615
2616                 $dbw->delete(
2617                         'protected_titles',
2618                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2619                         __METHOD__
2620                 );
2621                 $this->mTitleProtection = false;
2622         }
2623
2624         /**
2625          * Is this page "semi-protected" - the *only* protection levels are listed
2626          * in $wgSemiprotectedRestrictionLevels?
2627          *
2628          * @param string $action Action to check (default: edit)
2629          * @return bool
2630          */
2631         public function isSemiProtected( $action = 'edit' ) {
2632                 global $wgSemiprotectedRestrictionLevels;
2633
2634                 $restrictions = $this->getRestrictions( $action );
2635                 $semi = $wgSemiprotectedRestrictionLevels;
2636                 if ( !$restrictions || !$semi ) {
2637                         // Not protected, or all protection is full protection
2638                         return false;
2639                 }
2640
2641                 // Remap autoconfirmed to editsemiprotected for BC
2642                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2643                         $semi[$key] = 'editsemiprotected';
2644                 }
2645                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2646                         $restrictions[$key] = 'editsemiprotected';
2647                 }
2648
2649                 return !array_diff( $restrictions, $semi );
2650         }
2651
2652         /**
2653          * Does the title correspond to a protected article?
2654          *
2655          * @param string $action the action the page is protected from,
2656          * by default checks all actions.
2657          * @return bool
2658          */
2659         public function isProtected( $action = '' ) {
2660                 global $wgRestrictionLevels;
2661
2662                 $restrictionTypes = $this->getRestrictionTypes();
2663
2664                 # Special pages have inherent protection
2665                 if ( $this->isSpecialPage() ) {
2666                         return true;
2667                 }
2668
2669                 # Check regular protection levels
2670                 foreach ( $restrictionTypes as $type ) {
2671                         if ( $action == $type || $action == '' ) {
2672                                 $r = $this->getRestrictions( $type );
2673                                 foreach ( $wgRestrictionLevels as $level ) {
2674                                         if ( in_array( $level, $r ) && $level != '' ) {
2675                                                 return true;
2676                                         }
2677                                 }
2678                         }
2679                 }
2680
2681                 return false;
2682         }
2683
2684         /**
2685          * Determines if $user is unable to edit this page because it has been protected
2686          * by $wgNamespaceProtection.
2687          *
2688          * @param User $user User object to check permissions
2689          * @return bool
2690          */
2691         public function isNamespaceProtected( User $user ) {
2692                 global $wgNamespaceProtection;
2693
2694                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2695                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2696                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2697                                         return true;
2698                                 }
2699                         }
2700                 }
2701                 return false;
2702         }
2703
2704         /**
2705          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2706          *
2707          * @return bool If the page is subject to cascading restrictions.
2708          */
2709         public function isCascadeProtected() {
2710                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2711                 return ( $sources > 0 );
2712         }
2713
2714         /**
2715          * Determines whether cascading protection sources have already been loaded from
2716          * the database.
2717          *
2718          * @param bool $getPages True to check if the pages are loaded, or false to check
2719          * if the status is loaded.
2720          * @return bool Whether or not the specified information has been loaded
2721          * @since 1.23
2722          */
2723         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2724                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2725         }
2726
2727         /**
2728          * Cascading protection: Get the source of any cascading restrictions on this page.
2729          *
2730          * @param bool $getPages Whether or not to retrieve the actual pages
2731          *        that the restrictions have come from and the actual restrictions
2732          *        themselves.
2733          * @return array Two elements: First is an array of Title objects of the
2734          *        pages from which cascading restrictions have come, false for
2735          *        none, or true if such restrictions exist but $getPages was not
2736          *        set. Second is an array like that returned by
2737          *        Title::getAllRestrictions(), or an empty array if $getPages is
2738          *        false.
2739          */
2740         public function getCascadeProtectionSources( $getPages = true ) {
2741                 global $wgContLang;
2742                 $pagerestrictions = array();
2743
2744                 if ( $this->mCascadeSources !== null && $getPages ) {
2745                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2746                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2747                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2748                 }
2749
2750                 wfProfileIn( __METHOD__ );
2751
2752                 $dbr = wfGetDB( DB_SLAVE );
2753
2754                 if ( $this->getNamespace() == NS_FILE ) {
2755                         $tables = array( 'imagelinks', 'page_restrictions' );
2756                         $where_clauses = array(
2757                                 'il_to' => $this->getDBkey(),
2758                                 'il_from=pr_page',
2759                                 'pr_cascade' => 1
2760                         );
2761                 } else {
2762                         $tables = array( 'templatelinks', 'page_restrictions' );
2763                         $where_clauses = array(
2764                                 'tl_namespace' => $this->getNamespace(),
2765                                 'tl_title' => $this->getDBkey(),
2766                                 'tl_from=pr_page',
2767                                 'pr_cascade' => 1
2768                         );
2769                 }
2770
2771                 if ( $getPages ) {
2772                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2773                                 'pr_expiry', 'pr_type', 'pr_level' );
2774                         $where_clauses[] = 'page_id=pr_page';
2775                         $tables[] = 'page';
2776                 } else {
2777                         $cols = array( 'pr_expiry' );
2778                 }
2779
2780                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2781
2782                 $sources = $getPages ? array() : false;
2783                 $now = wfTimestampNow();
2784                 $purgeExpired = false;
2785
2786                 foreach ( $res as $row ) {
2787                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2788                         if ( $expiry > $now ) {
2789                                 if ( $getPages ) {
2790                                         $page_id = $row->pr_page;
2791                                         $page_ns = $row->page_namespace;
2792                                         $page_title = $row->page_title;
2793                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2794                                         # Add groups needed for each restriction type if its not already there
2795                                         # Make sure this restriction type still exists
2796
2797                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2798                                                 $pagerestrictions[$row->pr_type] = array();
2799                                         }
2800
2801                                         if (
2802                                                 isset( $pagerestrictions[$row->pr_type] )
2803                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2804                                         ) {
2805                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2806                                         }
2807                                 } else {
2808                                         $sources = true;
2809                                 }
2810                         } else {
2811                                 // Trigger lazy purge of expired restrictions from the db
2812                                 $purgeExpired = true;
2813                         }
2814                 }
2815                 if ( $purgeExpired ) {
2816                         Title::purgeExpiredRestrictions();
2817                 }
2818
2819                 if ( $getPages ) {
2820                         $this->mCascadeSources = $sources;
2821                         $this->mCascadingRestrictions = $pagerestrictions;
2822                 } else {
2823                         $this->mHasCascadingRestrictions = $sources;
2824                 }
2825
2826                 wfProfileOut( __METHOD__ );
2827                 return array( $sources, $pagerestrictions );
2828         }
2829
2830         /**
2831          * Accessor for mRestrictionsLoaded
2832          *
2833          * @return bool Whether or not the page's restrictions have already been
2834          * loaded from the database
2835          * @since 1.23
2836          */
2837         public function areRestrictionsLoaded() {
2838                 return $this->mRestrictionsLoaded;
2839         }
2840
2841         /**
2842          * Accessor/initialisation for mRestrictions
2843          *
2844          * @param string $action Action that permission needs to be checked for
2845          * @return array Restriction levels needed to take the action. All levels
2846          *     are required.
2847          */
2848         public function getRestrictions( $action ) {
2849                 if ( !$this->mRestrictionsLoaded ) {
2850                         $this->loadRestrictions();
2851                 }
2852                 return isset( $this->mRestrictions[$action] )
2853                                 ? $this->mRestrictions[$action]
2854                                 : array();
2855         }
2856
2857         /**
2858          * Accessor/initialisation for mRestrictions
2859          *
2860          * @return array Keys are actions, values are arrays as returned by
2861          *     Title::getRestrictions()
2862          * @since 1.23
2863          */
2864         public function getAllRestrictions() {
2865                 if ( !$this->mRestrictionsLoaded ) {
2866                         $this->loadRestrictions();
2867                 }
2868                 return $this->mRestrictions;
2869         }
2870
2871         /**
2872          * Get the expiry time for the restriction against a given action
2873          *
2874          * @param string $action
2875          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2876          *     or not protected at all, or false if the action is not recognised.
2877          */
2878         public function getRestrictionExpiry( $action ) {
2879                 if ( !$this->mRestrictionsLoaded ) {
2880                         $this->loadRestrictions();
2881                 }
2882                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2883         }
2884
2885         /**
2886          * Returns cascading restrictions for the current article
2887          *
2888          * @return bool
2889          */
2890         function areRestrictionsCascading() {
2891                 if ( !$this->mRestrictionsLoaded ) {
2892                         $this->loadRestrictions();
2893                 }
2894
2895                 return $this->mCascadeRestriction;
2896         }
2897
2898         /**
2899          * Loads a string into mRestrictions array
2900          *
2901          * @param ResultWrapper $res Resource restrictions as an SQL result.
2902          * @param string $oldFashionedRestrictions Comma-separated list of page
2903          *        restrictions from page table (pre 1.10)
2904          */
2905         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2906                 $rows = array();
2907
2908                 foreach ( $res as $row ) {
2909                         $rows[] = $row;
2910                 }
2911
2912                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2913         }
2914
2915         /**
2916          * Compiles list of active page restrictions from both page table (pre 1.10)
2917          * and page_restrictions table for this existing page.
2918          * Public for usage by LiquidThreads.
2919          *
2920          * @param array $rows Array of db result objects
2921          * @param string $oldFashionedRestrictions Comma-separated list of page
2922          *   restrictions from page table (pre 1.10)
2923          */
2924         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2925                 global $wgContLang;
2926                 $dbr = wfGetDB( DB_SLAVE );
2927
2928                 $restrictionTypes = $this->getRestrictionTypes();
2929
2930                 foreach ( $restrictionTypes as $type ) {
2931                         $this->mRestrictions[$type] = array();
2932                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2933                 }
2934
2935                 $this->mCascadeRestriction = false;
2936
2937                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2938
2939                 if ( $oldFashionedRestrictions === null ) {
2940                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2941                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2942                 }
2943
2944                 if ( $oldFashionedRestrictions != '' ) {
2945
2946                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2947                                 $temp = explode( '=', trim( $restrict ) );
2948                                 if ( count( $temp ) == 1 ) {
2949                                         // old old format should be treated as edit/move restriction
2950                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2951                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2952                                 } else {
2953                                         $restriction = trim( $temp[1] );
2954                                         if ( $restriction != '' ) { //some old entries are empty
2955                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2956                                         }
2957                                 }
2958                         }
2959
2960                         $this->mOldRestrictions = true;
2961
2962                 }
2963
2964                 if ( count( $rows ) ) {
2965                         # Current system - load second to make them override.
2966                         $now = wfTimestampNow();
2967                         $purgeExpired = false;
2968
2969                         # Cycle through all the restrictions.
2970                         foreach ( $rows as $row ) {
2971
2972                                 // Don't take care of restrictions types that aren't allowed
2973                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2974                                         continue;
2975                                 }
2976
2977                                 // This code should be refactored, now that it's being used more generally,
2978                                 // But I don't really see any harm in leaving it in Block for now -werdna
2979                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2980
2981                                 // Only apply the restrictions if they haven't expired!
2982                                 if ( !$expiry || $expiry > $now ) {
2983                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2984                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2985
2986                                         $this->mCascadeRestriction |= $row->pr_cascade;
2987                                 } else {
2988                                         // Trigger a lazy purge of expired restrictions
2989                                         $purgeExpired = true;
2990                                 }
2991                         }
2992
2993                         if ( $purgeExpired ) {
2994                                 Title::purgeExpiredRestrictions();
2995                         }
2996                 }
2997
2998                 $this->mRestrictionsLoaded = true;
2999         }
3000
3001         /**
3002          * Load restrictions from the page_restrictions table
3003          *
3004          * @param string $oldFashionedRestrictions Comma-separated list of page
3005          *   restrictions from page table (pre 1.10)
3006          */
3007         public function loadRestrictions( $oldFashionedRestrictions = null ) {
3008                 global $wgContLang;
3009                 if ( !$this->mRestrictionsLoaded ) {
3010                         if ( $this->exists() ) {
3011                                 $dbr = wfGetDB( DB_SLAVE );
3012
3013                                 $res = $dbr->select(
3014                                         'page_restrictions',
3015                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
3016                                         array( 'pr_page' => $this->getArticleID() ),
3017                                         __METHOD__
3018                                 );
3019
3020                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
3021                         } else {
3022                                 $title_protection = $this->getTitleProtection();
3023
3024                                 if ( $title_protection ) {
3025                                         $now = wfTimestampNow();
3026                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
3027
3028                                         if ( !$expiry || $expiry > $now ) {
3029                                                 // Apply the restrictions
3030                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3031                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
3032                                         } else { // Get rid of the old restrictions
3033                                                 Title::purgeExpiredRestrictions();
3034                                                 $this->mTitleProtection = false;
3035                                         }
3036                                 } else {
3037                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
3038                                 }
3039                                 $this->mRestrictionsLoaded = true;
3040                         }
3041                 }
3042         }
3043
3044         /**
3045          * Flush the protection cache in this object and force reload from the database.
3046          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3047          */
3048         public function flushRestrictions() {
3049                 $this->mRestrictionsLoaded = false;
3050                 $this->mTitleProtection = null;
3051         }
3052
3053         /**
3054          * Purge expired restrictions from the page_restrictions table
3055          */
3056         static function purgeExpiredRestrictions() {
3057                 if ( wfReadOnly() ) {
3058                         return;
3059                 }
3060
3061                 $method = __METHOD__;
3062                 $dbw = wfGetDB( DB_MASTER );
3063                 $dbw->onTransactionIdle( function() use ( $dbw, $method ) {
3064                         $dbw->delete(
3065                                 'page_restrictions',
3066                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3067                                 $method
3068                         );
3069                         $dbw->delete(
3070                                 'protected_titles',
3071                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3072                                 $method
3073                         );
3074                 } );
3075         }
3076
3077         /**
3078          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3079          *
3080          * @return bool
3081          */
3082         public function hasSubpages() {
3083                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3084                         # Duh
3085                         return false;
3086                 }
3087
3088                 # We dynamically add a member variable for the purpose of this method
3089                 # alone to cache the result.  There's no point in having it hanging
3090                 # around uninitialized in every Title object; therefore we only add it
3091                 # if needed and don't declare it statically.
3092                 if ( $this->mHasSubpages === null ) {
3093                         $this->mHasSubpages = false;
3094                         $subpages = $this->getSubpages( 1 );
3095                         if ( $subpages instanceof TitleArray ) {
3096                                 $this->mHasSubpages = (bool)$subpages->count();
3097                         }
3098                 }
3099
3100                 return $this->mHasSubpages;
3101         }
3102
3103         /**
3104          * Get all subpages of this page.
3105          *
3106          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3107          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3108          *  doesn't allow subpages
3109          */
3110         public function getSubpages( $limit = -1 ) {
3111                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3112                         return array();
3113                 }
3114
3115                 $dbr = wfGetDB( DB_SLAVE );
3116                 $conds['page_namespace'] = $this->getNamespace();
3117                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3118                 $options = array();
3119                 if ( $limit > -1 ) {
3120                         $options['LIMIT'] = $limit;
3121                 }
3122                 $this->mSubpages = TitleArray::newFromResult(
3123                         $dbr->select( 'page',
3124                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3125                                 $conds,
3126                                 __METHOD__,
3127                                 $options
3128                         )
3129                 );
3130                 return $this->mSubpages;
3131         }
3132
3133         /**
3134          * Is there a version of this page in the deletion archive?
3135          *
3136          * @return int The number of archived revisions
3137          */
3138         public function isDeleted() {
3139                 if ( $this->getNamespace() < 0 ) {
3140                         $n = 0;
3141                 } else {
3142                         $dbr = wfGetDB( DB_SLAVE );
3143
3144                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3145                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3146                                 __METHOD__
3147                         );
3148                         if ( $this->getNamespace() == NS_FILE ) {
3149                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3150                                         array( 'fa_name' => $this->getDBkey() ),
3151                                         __METHOD__
3152                                 );
3153                         }
3154                 }
3155                 return (int)$n;
3156         }
3157
3158         /**
3159          * Is there a version of this page in the deletion archive?
3160          *
3161          * @return bool
3162          */
3163         public function isDeletedQuick() {
3164                 if ( $this->getNamespace() < 0 ) {
3165                         return false;
3166                 }
3167                 $dbr = wfGetDB( DB_SLAVE );
3168                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3169                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3170                         __METHOD__
3171                 );
3172                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3173                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3174                                 array( 'fa_name' => $this->getDBkey() ),
3175                                 __METHOD__
3176                         );
3177                 }
3178                 return $deleted;
3179         }
3180
3181         /**
3182          * Get the article ID for this Title from the link cache,
3183          * adding it if necessary
3184          *
3185          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3186          *  for update
3187          * @return int The ID
3188          */
3189         public function getArticleID( $flags = 0 ) {
3190                 if ( $this->getNamespace() < 0 ) {
3191                         $this->mArticleID = 0;
3192                         return $this->mArticleID;
3193                 }
3194                 $linkCache = LinkCache::singleton();
3195                 if ( $flags & self::GAID_FOR_UPDATE ) {
3196                         $oldUpdate = $linkCache->forUpdate( true );
3197                         $linkCache->clearLink( $this );
3198                         $this->mArticleID = $linkCache->addLinkObj( $this );
3199                         $linkCache->forUpdate( $oldUpdate );
3200                 } else {
3201                         if ( -1 == $this->mArticleID ) {
3202                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3203                         }
3204                 }
3205                 return $this->mArticleID;
3206         }
3207
3208         /**
3209          * Is this an article that is a redirect page?
3210          * Uses link cache, adding it if necessary
3211          *
3212          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3213          * @return bool
3214          */
3215         public function isRedirect( $flags = 0 ) {
3216                 if ( !is_null( $this->mRedirect ) ) {
3217                         return $this->mRedirect;
3218                 }
3219                 # Calling getArticleID() loads the field from cache as needed
3220                 if ( !$this->getArticleID( $flags ) ) {
3221                         $this->mRedirect = false;
3222                         return $this->mRedirect;
3223                 }
3224
3225                 $linkCache = LinkCache::singleton();
3226                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3227                 if ( $cached === null ) {
3228                         # Trust LinkCache's state over our own
3229                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3230                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3231                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3232                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3233                         # LinkCache to refresh its data from the master.
3234                         $this->mRedirect = false;
3235                         return $this->mRedirect;
3236                 }
3237
3238                 $this->mRedirect = (bool)$cached;
3239
3240                 return $this->mRedirect;
3241         }
3242
3243         /**
3244          * What is the length of this page?
3245          * Uses link cache, adding it if necessary
3246          *
3247          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3248          * @return int
3249          */
3250         public function getLength( $flags = 0 ) {
3251                 if ( $this->mLength != -1 ) {
3252                         return $this->mLength;
3253                 }
3254                 # Calling getArticleID() loads the field from cache as needed
3255                 if ( !$this->getArticleID( $flags ) ) {
3256                         $this->mLength = 0;
3257                         return $this->mLength;
3258                 }
3259                 $linkCache = LinkCache::singleton();
3260                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3261                 if ( $cached === null ) {
3262                         # Trust LinkCache's state over our own, as for isRedirect()
3263                         $this->mLength = 0;
3264                         return $this->mLength;
3265                 }
3266
3267                 $this->mLength = intval( $cached );
3268
3269                 return $this->mLength;
3270         }
3271
3272         /**
3273          * What is the page_latest field for this page?
3274          *
3275          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3276          * @return int Int or 0 if the page doesn't exist
3277          */
3278         public function getLatestRevID( $flags = 0 ) {
3279                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3280                         return intval( $this->mLatestID );
3281                 }
3282                 # Calling getArticleID() loads the field from cache as needed
3283                 if ( !$this->getArticleID( $flags ) ) {
3284                         $this->mLatestID = 0;
3285                         return $this->mLatestID;
3286                 }
3287                 $linkCache = LinkCache::singleton();
3288                 $linkCache->addLinkObj( $this );
3289                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3290                 if ( $cached === null ) {
3291                         # Trust LinkCache's state over our own, as for isRedirect()
3292                         $this->mLatestID = 0;
3293                         return $this->mLatestID;
3294                 }
3295
3296                 $this->mLatestID = intval( $cached );
3297
3298                 return $this->mLatestID;
3299         }
3300
3301         /**
3302          * This clears some fields in this object, and clears any associated
3303          * keys in the "bad links" section of the link cache.
3304          *
3305          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3306          * loading of the new page_id. It's also called from
3307          * WikiPage::doDeleteArticleReal()
3308          *
3309          * @param int $newid The new Article ID
3310          */
3311         public function resetArticleID( $newid ) {
3312                 $linkCache = LinkCache::singleton();
3313                 $linkCache->clearLink( $this );
3314
3315                 if ( $newid === false ) {
3316                         $this->mArticleID = -1;
3317                 } else {
3318                         $this->mArticleID = intval( $newid );
3319                 }
3320                 $this->mRestrictionsLoaded = false;
3321                 $this->mRestrictions = array();
3322                 $this->mRedirect = null;
3323                 $this->mLength = -1;
3324                 $this->mLatestID = false;
3325                 $this->mContentModel = false;
3326                 $this->mEstimateRevisions = null;
3327                 $this->mPageLanguage = false;
3328                 $this->mDbPageLanguage = null;
3329         }
3330
3331         /**
3332          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3333          *
3334          * @param string $text Containing title to capitalize
3335          * @param int $ns Namespace index, defaults to NS_MAIN
3336          * @return string Containing capitalized title
3337          */
3338         public static function capitalize( $text, $ns = NS_MAIN ) {
3339                 global $wgContLang;
3340
3341                 if ( MWNamespace::isCapitalized( $ns ) ) {
3342                         return $wgContLang->ucfirst( $text );
3343                 } else {
3344                         return $text;
3345                 }
3346         }
3347
3348         /**
3349          * Secure and split - main initialisation function for this object
3350          *
3351          * Assumes that mDbkeyform has been set, and is urldecoded
3352          * and uses underscores, but not otherwise munged.  This function
3353          * removes illegal characters, splits off the interwiki and
3354          * namespace prefixes, sets the other forms, and canonicalizes
3355          * everything.
3356          *
3357          * @return bool True on success
3358          */
3359         private function secureAndSplit() {
3360                 # Initialisation
3361                 $this->mInterwiki = '';
3362                 $this->mFragment = '';
3363                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3364
3365                 $dbkey = $this->mDbkeyform;
3366
3367                 try {
3368                         // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3369                         //        the parsing code with Title, while avoiding massive refactoring.
3370                         // @todo: get rid of secureAndSplit, refactor parsing code.
3371                         $parser = $this->getTitleParser();
3372                         $parts = $parser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3373                 } catch ( MalformedTitleException $ex ) {
3374                         return false;
3375                 }
3376
3377                 # Fill fields
3378                 $this->setFragment( '#' . $parts['fragment'] );
3379                 $this->mInterwiki = $parts['interwiki'];
3380                 $this->mNamespace = $parts['namespace'];
3381                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3382
3383                 $this->mDbkeyform = $parts['dbkey'];
3384                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3385                 $this->mTextform = str_replace( '_', ' ', $this->mDbkeyform );
3386
3387                 # We already know that some pages won't be in the database!
3388                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3389                         $this->mArticleID = 0;
3390                 }
3391
3392                 return true;
3393         }
3394
3395         /**
3396          * Get an array of Title objects linking to this Title
3397          * Also stores the IDs in the link cache.
3398          *
3399          * WARNING: do not use this function on arbitrary user-supplied titles!
3400          * On heavily-used templates it will max out the memory.
3401          *
3402          * @param array $options May be FOR UPDATE
3403          * @param string $table Table name
3404          * @param string $prefix Fields prefix
3405          * @return Title[] Array of Title objects linking here
3406          */
3407         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3408                 if ( count( $options ) > 0 ) {
3409                         $db = wfGetDB( DB_MASTER );
3410                 } else {
3411                         $db = wfGetDB( DB_SLAVE );
3412                 }
3413
3414                 $res = $db->select(
3415                         array( 'page', $table ),
3416                         self::getSelectFields(),
3417                         array(
3418                                 "{$prefix}_from=page_id",
3419                                 "{$prefix}_namespace" => $this->getNamespace(),
3420                                 "{$prefix}_title" => $this->getDBkey() ),
3421                         __METHOD__,
3422                         $options
3423                 );
3424
3425                 $retVal = array();
3426                 if ( $res->numRows() ) {
3427                         $linkCache = LinkCache::singleton();
3428                         foreach ( $res as $row ) {
3429                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3430                                 if ( $titleObj ) {
3431                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3432                                         $retVal[] = $titleObj;
3433                                 }
3434                         }
3435                 }
3436                 return $retVal;
3437         }
3438
3439         /**
3440          * Get an array of Title objects using this Title as a template
3441          * Also stores the IDs in the link cache.
3442          *
3443          * WARNING: do not use this function on arbitrary user-supplied titles!
3444          * On heavily-used templates it will max out the memory.
3445          *
3446          * @param array $options May be FOR UPDATE
3447          * @return Title[] Array of Title the Title objects linking here
3448          */
3449         public function getTemplateLinksTo( $options = array() ) {
3450                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3451         }
3452
3453         /**
3454          * Get an array of Title objects linked from this Title
3455          * Also stores the IDs in the link cache.
3456          *
3457          * WARNING: do not use this function on arbitrary user-supplied titles!
3458          * On heavily-used templates it will max out the memory.
3459          *
3460          * @param array $options May be FOR UPDATE
3461          * @param string $table Table name
3462          * @param string $prefix Fields prefix
3463          * @return array Array of Title objects linking here
3464          */
3465         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3466                 global $wgContentHandlerUseDB;
3467
3468                 $id = $this->getArticleID();
3469
3470                 # If the page doesn't exist; there can't be any link from this page
3471                 if ( !$id ) {
3472                         return array();
3473                 }
3474
3475                 if ( count( $options ) > 0 ) {
3476                         $db = wfGetDB( DB_MASTER );
3477                 } else {
3478                         $db = wfGetDB( DB_SLAVE );
3479                 }
3480
3481                 $namespaceFiled = "{$prefix}_namespace";
3482                 $titleField = "{$prefix}_title";
3483
3484                 $fields = array(
3485                         $namespaceFiled,
3486                         $titleField,
3487                         'page_id',
3488                         'page_len',
3489                         'page_is_redirect',
3490                         'page_latest'
3491                 );
3492
3493                 if ( $wgContentHandlerUseDB ) {
3494                         $fields[] = 'page_content_model';
3495                 }
3496
3497                 $res = $db->select(
3498                         array( $table, 'page' ),
3499                         $fields,
3500                         array( "{$prefix}_from" => $id ),
3501                         __METHOD__,
3502                         $options,
3503                         array( 'page' => array(
3504                                 'LEFT JOIN',
3505                                 array( "page_namespace=$namespaceFiled", "page_title=$titleField" )
3506                         ) )
3507                 );
3508
3509                 $retVal = array();
3510                 if ( $res->numRows() ) {
3511                         $linkCache = LinkCache::singleton();
3512                         foreach ( $res as $row ) {
3513                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3514                                 if ( $titleObj ) {
3515                                         if ( $row->page_id ) {
3516                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3517                                         } else {
3518                                                 $linkCache->addBadLinkObj( $titleObj );
3519                                         }
3520                                         $retVal[] = $titleObj;
3521                                 }
3522                         }
3523                 }
3524                 return $retVal;
3525         }
3526
3527         /**
3528          * Get an array of Title objects used on this Title as a template
3529          * Also stores the IDs in the link cache.
3530          *
3531          * WARNING: do not use this function on arbitrary user-supplied titles!
3532          * On heavily-used templates it will max out the memory.
3533          *
3534          * @param array $options May be FOR UPDATE
3535          * @return Title[] Array of Title the Title objects used here
3536          */
3537         public function getTemplateLinksFrom( $options = array() ) {
3538                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3539         }
3540
3541         /**
3542          * Get an array of Title objects referring to non-existent articles linked
3543          * from this page.
3544          *
3545          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3546          *   should use redirect table in this case).
3547          * @return Title[] Array of Title the Title objects
3548          */
3549         public function getBrokenLinksFrom() {
3550                 if ( $this->getArticleID() == 0 ) {
3551                         # All links from article ID 0 are false positives
3552                         return array();
3553                 }
3554
3555                 $dbr = wfGetDB( DB_SLAVE );
3556                 $res = $dbr->select(
3557                         array( 'page', 'pagelinks' ),
3558                         array( 'pl_namespace', 'pl_title' ),
3559                         array(
3560                                 'pl_from' => $this->getArticleID(),
3561                                 'page_namespace IS NULL'
3562                         ),
3563                         __METHOD__, array(),
3564                         array(
3565                                 'page' => array(
3566                                         'LEFT JOIN',
3567                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3568                                 )
3569                         )
3570                 );
3571
3572                 $retVal = array();
3573                 foreach ( $res as $row ) {
3574                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3575                 }
3576                 return $retVal;
3577         }
3578
3579         /**
3580          * Get a list of URLs to purge from the Squid cache when this
3581          * page changes
3582          *
3583          * @return string[] Array of String the URLs
3584          */
3585         public function getSquidURLs() {
3586                 $urls = array(
3587                         $this->getInternalURL(),
3588                         $this->getInternalURL( 'action=history' )
3589                 );
3590
3591                 $pageLang = $this->getPageLanguage();
3592                 if ( $pageLang->hasVariants() ) {
3593                         $variants = $pageLang->getVariants();
3594                         foreach ( $variants as $vCode ) {
3595                                 $urls[] = $this->getInternalURL( '', $vCode );
3596                         }
3597                 }
3598
3599                 // If we are looking at a css/js user subpage, purge the action=raw.
3600                 if ( $this->isJsSubpage() ) {
3601                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3602                 } elseif ( $this->isCssSubpage() ) {
3603                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3604                 }
3605
3606                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3607                 return $urls;
3608         }
3609
3610         /**
3611          * Purge all applicable Squid URLs
3612          */
3613         public function purgeSquid() {
3614                 global $wgUseSquid;
3615                 if ( $wgUseSquid ) {
3616                         $urls = $this->getSquidURLs();
3617                         $u = new SquidUpdate( $urls );
3618                         $u->doUpdate();
3619                 }
3620         }
3621
3622         /**
3623          * Move this page without authentication
3624          *
3625          * @param Title $nt The new page Title
3626          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3627          */
3628         public function moveNoAuth( &$nt ) {
3629                 return $this->moveTo( $nt, false );
3630         }
3631
3632         /**
3633          * Check whether a given move operation would be valid.
3634          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3635          *
3636          * @param Title $nt The new title
3637          * @param bool $auth Indicates whether $wgUser's permissions
3638          *  should be checked
3639          * @param string $reason Is the log summary of the move, used for spam checking
3640          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3641          */
3642         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3643                 global $wgUser, $wgContentHandlerUseDB;
3644
3645                 $errors = array();
3646                 if ( !$nt ) {
3647                         // Normally we'd add this to $errors, but we'll get
3648                         // lots of syntax errors if $nt is not an object
3649                         return array( array( 'badtitletext' ) );
3650                 }
3651                 if ( $this->equals( $nt ) ) {
3652                         $errors[] = array( 'selfmove' );
3653                 }
3654                 if ( !$this->isMovable() ) {
3655                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3656                 }
3657                 if ( $nt->isExternal() ) {
3658                         $errors[] = array( 'immobile-target-namespace-iw' );
3659                 }
3660                 if ( !$nt->isMovable() ) {
3661                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3662                 }
3663
3664                 $oldid = $this->getArticleID();
3665                 $newid = $nt->getArticleID();
3666
3667                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3668                         $errors[] = array( 'articleexists' );
3669                 }
3670                 if (
3671                         ( $this->getDBkey() == '' ) ||
3672                         ( !$oldid ) ||
3673                         ( $nt->getDBkey() == '' )
3674                 ) {
3675                         $errors[] = array( 'badarticleerror' );
3676                 }
3677
3678                 // Content model checks
3679                 if ( !$wgContentHandlerUseDB &&
3680                                 $this->getContentModel() !== $nt->getContentModel() ) {
3681                         // can't move a page if that would change the page's content model
3682                         $errors[] = array(
3683                                 'bad-target-model',
3684                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3685                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3686                         );
3687                 }
3688
3689                 // Image-specific checks
3690                 if ( $this->getNamespace() == NS_FILE ) {
3691                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3692                 }
3693
3694                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3695                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3696                 }
3697
3698                 if ( $auth ) {
3699                         $errors = wfMergeErrorArrays( $errors,
3700                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3701                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3702                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3703                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3704                 }
3705
3706                 $match = EditPage::matchSummarySpamRegex( $reason );
3707                 if ( $match !== false ) {
3708                         // This is kind of lame, won't display nice
3709                         $errors[] = array( 'spamprotectiontext' );
3710                 }
3711
3712                 $err = null;
3713                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3714                         $errors[] = array( 'hookaborted', $err );
3715                 }
3716
3717                 # The move is allowed only if (1) the target doesn't exist, or
3718                 # (2) the target is a redirect to the source, and has no history
3719                 # (so we can undo bad moves right after they're done).
3720
3721                 if ( 0 != $newid ) { # Target exists; check for validity
3722                         if ( !$this->isValidMoveTarget( $nt ) ) {
3723                                 $errors[] = array( 'articleexists' );
3724                         }
3725                 } else {
3726                         $tp = $nt->getTitleProtection();
3727                         $right = $tp['pt_create_perm'];
3728                         if ( $right == 'sysop' ) {
3729                                 $right = 'editprotected'; // B/C
3730                         }
3731                         if ( $right == 'autoconfirmed' ) {
3732                                 $right = 'editsemiprotected'; // B/C
3733                         }
3734                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3735                                 $errors[] = array( 'cantmove-titleprotected' );
3736                         }
3737                 }
3738                 if ( empty( $errors ) ) {
3739                         return true;
3740                 }
3741                 return $errors;
3742         }
3743
3744         /**
3745          * Check if the requested move target is a valid file move target
3746          * @param Title $nt Target title
3747          * @return array List of errors
3748          */
3749         protected function validateFileMoveOperation( $nt ) {
3750                 global $wgUser;
3751
3752                 $errors = array();
3753
3754                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3755
3756                 $file = wfLocalFile( $this );
3757                 if ( $file->exists() ) {
3758                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3759                                 $errors[] = array( 'imageinvalidfilename' );
3760                         }
3761                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3762                                 $errors[] = array( 'imagetypemismatch' );
3763                         }
3764                 }
3765
3766                 if ( $nt->getNamespace() != NS_FILE ) {
3767                         $errors[] = array( 'imagenocrossnamespace' );
3768                         // From here we want to do checks on a file object, so if we can't
3769                         // create one, we must return.
3770                         return $errors;
3771                 }
3772
3773                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3774
3775                 $destFile = wfLocalFile( $nt );
3776                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3777                         $errors[] = array( 'file-exists-sharedrepo' );
3778                 }
3779
3780                 return $errors;
3781         }
3782
3783         /**
3784          * Move a title to a new location
3785          *
3786          * @param Title $nt The new title
3787          * @param bool $auth Indicates whether $wgUser's permissions
3788          *  should be checked
3789          * @param string $reason The reason for the move
3790          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3791          *  Ignored if the user doesn't have the suppressredirect right.
3792          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3793          */
3794         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3795                 global $wgUser;
3796                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3797                 if ( is_array( $err ) ) {
3798                         // Auto-block user's IP if the account was "hard" blocked
3799                         $wgUser->spreadAnyEditBlock();
3800                         return $err;
3801                 }
3802                 // Check suppressredirect permission
3803                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3804                         $createRedirect = true;
3805                 }
3806
3807                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3808
3809                 // If it is a file, move it first.
3810                 // It is done before all other moving stuff is done because it's hard to revert.
3811                 $dbw = wfGetDB( DB_MASTER );
3812                 if ( $this->getNamespace() == NS_FILE ) {
3813                         $file = wfLocalFile( $this );
3814                         if ( $file->exists() ) {
3815                                 $status = $file->move( $nt );
3816                                 if ( !$status->isOk() ) {
3817                                         return $status->getErrorsArray();
3818                                 }
3819                         }
3820                         // Clear RepoGroup process cache
3821                         RepoGroup::singleton()->clearCache( $this );
3822                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3823                 }
3824
3825                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3826                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3827                 $protected = $this->isProtected();
3828
3829                 // Do the actual move
3830                 $this->moveToInternal( $nt, $reason, $createRedirect );
3831
3832                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3833                 // cl_timestamp, which may disturb time-based lists on some sites.
3834                 $prefixes = $dbw->select(
3835                         'categorylinks',
3836                         array( 'cl_sortkey_prefix', 'cl_to' ),
3837                         array( 'cl_from' => $pageid ),
3838                         __METHOD__
3839                 );
3840                 foreach ( $prefixes as $prefixRow ) {
3841                         $prefix = $prefixRow->cl_sortkey_prefix;
3842                         $catTo = $prefixRow->cl_to;
3843                         $dbw->update( 'categorylinks',
3844                                 array(
3845                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3846                                                 $nt->getCategorySortkey( $prefix ) ),
3847                                         'cl_timestamp=cl_timestamp' ),
3848                                 array(
3849                                         'cl_from' => $pageid,
3850                                         'cl_to' => $catTo ),
3851                                 __METHOD__
3852                         );
3853                 }
3854
3855                 $redirid = $this->getArticleID();
3856
3857                 if ( $protected ) {
3858                         # Protect the redirect title as the title used to be...
3859                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3860                                 array(
3861                                         'pr_page' => $redirid,
3862                                         'pr_type' => 'pr_type',
3863                                         'pr_level' => 'pr_level',
3864                                         'pr_cascade' => 'pr_cascade',
3865                                         'pr_user' => 'pr_user',
3866                                         'pr_expiry' => 'pr_expiry'
3867                                 ),
3868                                 array( 'pr_page' => $pageid ),
3869                                 __METHOD__,
3870                                 array( 'IGNORE' )
3871                         );
3872                         # Update the protection log
3873                         $log = new LogPage( 'protect' );
3874                         $comment = wfMessage(
3875                                 'prot_1movedto2',
3876                                 $this->getPrefixedText(),
3877                                 $nt->getPrefixedText()
3878                         )->inContentLanguage()->text();
3879                         if ( $reason ) {
3880                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3881                         }
3882                         // @todo FIXME: $params?
3883                         $logId = $log->addEntry(
3884                                 'move_prot',
3885                                 $nt,
3886                                 $comment,
3887                                 array( $this->getPrefixedText() ),
3888                                 $wgUser
3889                         );
3890
3891                         // reread inserted pr_ids for log relation
3892                         $insertedPrIds = $dbw->select(
3893                                 'page_restrictions',
3894                                 'pr_id',
3895                                 array( 'pr_page' => $redirid ),
3896                                 __METHOD__
3897                         );
3898                         $logRelationsValues = array();
3899                         foreach ( $insertedPrIds as $prid ) {
3900                                 $logRelationsValues[] = $prid->pr_id;
3901                         }
3902                         $log->addRelations( 'pr_id', $logRelationsValues, $logId );
3903                 }
3904
3905                 # Update watchlists
3906                 $oldnamespace = MWNamespace::getSubject( $this->getNamespace() );
3907                 $newnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3908                 $oldtitle = $this->getDBkey();
3909                 $newtitle = $nt->getDBkey();
3910
3911                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3912                         WatchedItem::duplicateEntries( $this, $nt );
3913                 }
3914
3915                 $dbw->commit( __METHOD__ );
3916
3917                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid, $reason ) );
3918                 return true;
3919         }
3920
3921         /**
3922          * Move page to a title which is either a redirect to the
3923          * source page or nonexistent
3924          *
3925          * @param Title $nt The page to move to, which should be a redirect or nonexistent
3926          * @param string $reason The reason for the move
3927          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3928          *   if the user has the suppressredirect right
3929          * @throws MWException
3930          */
3931         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3932                 global $wgUser, $wgContLang;
3933
3934                 if ( $nt->exists() ) {
3935                         $moveOverRedirect = true;
3936                         $logType = 'move_redir';
3937                 } else {
3938                         $moveOverRedirect = false;
3939                         $logType = 'move';
3940                 }
3941
3942                 if ( $createRedirect ) {
3943                         if ( $this->getNamespace() == NS_CATEGORY
3944                                 && !wfMessage( 'category-move-redirect-override' )->inContentLanguage()->isDisabled()
3945                         ) {
3946                                 $redirectContent = new WikitextContent(
3947                                         wfMessage( 'category-move-redirect-override' )
3948                                                 ->params( $nt->getPrefixedText() )->inContentLanguage()->plain() );
3949                         } else {
3950                                 $contentHandler = ContentHandler::getForTitle( $this );
3951                                 $redirectContent = $contentHandler->makeRedirectContent( $nt,
3952                                         wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3953                         }
3954
3955                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3956                 } else {
3957                         $redirectContent = null;
3958                 }
3959
3960                 $logEntry = new ManualLogEntry( 'move', $logType );
3961                 $logEntry->setPerformer( $wgUser );
3962                 $logEntry->setTarget( $this );
3963                 $logEntry->setComment( $reason );
3964                 $logEntry->setParameters( array(
3965                         '4::target' => $nt->getPrefixedText(),
3966                         '5::noredir' => $redirectContent ? '0': '1',
3967                 ) );
3968
3969                 $formatter = LogFormatter::newFromEntry( $logEntry );
3970                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3971                 $comment = $formatter->getPlainActionText();
3972                 if ( $reason ) {
3973                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3974                 }
3975                 # Truncate for whole multibyte characters.
3976                 $comment = $wgContLang->truncate( $comment, 255 );
3977
3978                 $oldid = $this->getArticleID();
3979
3980                 $dbw = wfGetDB( DB_MASTER );
3981
3982                 $newpage = WikiPage::factory( $nt );
3983
3984                 if ( $moveOverRedirect ) {
3985                         $newid = $nt->getArticleID();
3986                         $newcontent = $newpage->getContent();
3987
3988                         # Delete the old redirect. We don't save it to history since
3989                         # by definition if we've got here it's rather uninteresting.
3990                         # We have to remove it so that the next step doesn't trigger
3991                         # a conflict on the unique namespace+title index...
3992                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3993
3994                         $newpage->doDeleteUpdates( $newid, $newcontent );
3995                 }
3996
3997                 # Save a null revision in the page's history notifying of the move
3998                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true, $wgUser );
3999                 if ( !is_object( $nullRevision ) ) {
4000                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
4001                 }
4002
4003                 $nullRevision->insertOn( $dbw );
4004
4005                 # Change the name of the target page:
4006                 $dbw->update( 'page',
4007                         /* SET */ array(
4008                                 'page_namespace' => $nt->getNamespace(),
4009                                 'page_title' => $nt->getDBkey(),
4010                         ),
4011                         /* WHERE */ array( 'page_id' => $oldid ),
4012                         __METHOD__
4013                 );
4014
4015                 // clean up the old title before reset article id - bug 45348
4016                 if ( !$redirectContent ) {
4017                         WikiPage::onArticleDelete( $this );
4018                 }
4019
4020                 $this->resetArticleID( 0 ); // 0 == non existing
4021                 $nt->resetArticleID( $oldid );
4022                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
4023
4024                 $newpage->updateRevisionOn( $dbw, $nullRevision );
4025
4026                 wfRunHooks( 'NewRevisionFromEditComplete',
4027                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
4028
4029                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
4030
4031                 if ( !$moveOverRedirect ) {
4032                         WikiPage::onArticleCreate( $nt );
4033                 }
4034
4035                 # Recreate the redirect, this time in the other direction.
4036                 if ( $redirectContent ) {
4037                         $redirectArticle = WikiPage::factory( $this );
4038                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
4039                         $newid = $redirectArticle->insertOn( $dbw );
4040                         if ( $newid ) { // sanity
4041                                 $this->resetArticleID( $newid );
4042                                 $redirectRevision = new Revision( array(
4043                                         'title' => $this, // for determining the default content model
4044                                         'page' => $newid,
4045                                         'user_text' => $wgUser->getName(),
4046                                         'user' => $wgUser->getId(),
4047                                         'comment' => $comment,
4048                                         'content' => $redirectContent ) );
4049                                 $redirectRevision->insertOn( $dbw );
4050                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
4051
4052                                 wfRunHooks( 'NewRevisionFromEditComplete',
4053                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
4054
4055                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
4056                         }
4057                 }
4058
4059                 # Log the move
4060                 $logid = $logEntry->insert();
4061                 $logEntry->publish( $logid );
4062         }
4063
4064         /**
4065          * Move this page's subpages to be subpages of $nt
4066          *
4067          * @param Title $nt Move target
4068          * @param bool $auth Whether $wgUser's permissions should be checked
4069          * @param string $reason The reason for the move
4070          * @param bool $createRedirect Whether to create redirects from the old subpages to
4071          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4072          * @return array Array with old page titles as keys, and strings (new page titles) or
4073          *     arrays (errors) as values, or an error array with numeric indices if no pages
4074          *     were moved
4075          */
4076         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
4077                 global $wgMaximumMovedPages;
4078                 // Check permissions
4079                 if ( !$this->userCan( 'move-subpages' ) ) {
4080                         return array( 'cant-move-subpages' );
4081                 }
4082                 // Do the source and target namespaces support subpages?
4083                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4084                         return array( 'namespace-nosubpages',
4085                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
4086                 }
4087                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4088                         return array( 'namespace-nosubpages',
4089                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
4090                 }
4091
4092                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4093                 $retval = array();
4094                 $count = 0;
4095                 foreach ( $subpages as $oldSubpage ) {
4096                         $count++;
4097                         if ( $count > $wgMaximumMovedPages ) {
4098                                 $retval[$oldSubpage->getPrefixedText()] =
4099                                                 array( 'movepage-max-pages',
4100                                                         $wgMaximumMovedPages );
4101                                 break;
4102                         }
4103
4104                         // We don't know whether this function was called before
4105                         // or after moving the root page, so check both
4106                         // $this and $nt
4107                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4108                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4109                         ) {
4110                                 // When moving a page to a subpage of itself,
4111                                 // don't move it twice
4112                                 continue;
4113                         }
4114                         $newPageName = preg_replace(
4115                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4116                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4117                                         $oldSubpage->getDBkey() );
4118                         if ( $oldSubpage->isTalkPage() ) {
4119                                 $newNs = $nt->getTalkPage()->getNamespace();
4120                         } else {
4121                                 $newNs = $nt->getSubjectPage()->getNamespace();
4122                         }
4123                         # Bug 14385: we need makeTitleSafe because the new page names may
4124                         # be longer than 255 characters.
4125                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4126
4127                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4128                         if ( $success === true ) {
4129                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4130                         } else {
4131                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4132                         }
4133                 }
4134                 return $retval;
4135         }
4136
4137         /**
4138          * Checks if this page is just a one-rev redirect.
4139          * Adds lock, so don't use just for light purposes.
4140          *
4141          * @return bool
4142          */
4143         public function isSingleRevRedirect() {
4144                 global $wgContentHandlerUseDB;
4145
4146                 $dbw = wfGetDB( DB_MASTER );
4147
4148                 # Is it a redirect?
4149                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4150                 if ( $wgContentHandlerUseDB ) {
4151                         $fields[] = 'page_content_model';
4152                 }
4153
4154                 $row = $dbw->selectRow( 'page',
4155                         $fields,
4156                         $this->pageCond(),
4157                         __METHOD__,
4158                         array( 'FOR UPDATE' )
4159                 );
4160                 # Cache some fields we may want
4161                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4162                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4163                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4164                 $this->mContentModel = $row && isset( $row->page_content_model )
4165                         ? strval( $row->page_content_model )
4166                         : false;
4167
4168                 if ( !$this->mRedirect ) {
4169                         return false;
4170                 }
4171                 # Does the article have a history?
4172                 $row = $dbw->selectField( array( 'page', 'revision' ),
4173                         'rev_id',
4174                         array( 'page_namespace' => $this->getNamespace(),
4175                                 'page_title' => $this->getDBkey(),
4176                                 'page_id=rev_page',
4177                                 'page_latest != rev_id'
4178                         ),
4179                         __METHOD__,
4180                         array( 'FOR UPDATE' )
4181                 );
4182                 # Return true if there was no history
4183                 return ( $row === false );
4184         }
4185
4186         /**
4187          * Checks if $this can be moved to a given Title
4188          * - Selects for update, so don't call it unless you mean business
4189          *
4190          * @param Title $nt The new title to check
4191          * @return bool
4192          */
4193         public function isValidMoveTarget( $nt ) {
4194                 # Is it an existing file?
4195                 if ( $nt->getNamespace() == NS_FILE ) {
4196                         $file = wfLocalFile( $nt );
4197                         if ( $file->exists() ) {
4198                                 wfDebug( __METHOD__ . ": file exists\n" );
4199                                 return false;
4200                         }
4201                 }
4202                 # Is it a redirect with no history?
4203                 if ( !$nt->isSingleRevRedirect() ) {
4204                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4205                         return false;
4206                 }
4207                 # Get the article text
4208                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4209                 if ( !is_object( $rev ) ) {
4210                         return false;
4211                 }
4212                 $content = $rev->getContent();
4213                 # Does the redirect point to the source?
4214                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4215                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4216
4217                 if ( $redirTitle ) {
4218                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4219                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4220                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4221                                 return false;
4222                         } else {
4223                                 return true;
4224                         }
4225                 } else {
4226                         # Fail safe (not a redirect after all. strange.)
4227                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4228                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4229                         return false;
4230                 }
4231         }
4232
4233         /**
4234          * Get categories to which this Title belongs and return an array of
4235          * categories' names.
4236          *
4237          * @return array Array of parents in the form:
4238          *        $parent => $currentarticle
4239          */
4240         public function getParentCategories() {
4241                 global $wgContLang;
4242
4243                 $data = array();
4244
4245                 $titleKey = $this->getArticleID();
4246
4247                 if ( $titleKey === 0 ) {
4248                         return $data;
4249                 }
4250
4251                 $dbr = wfGetDB( DB_SLAVE );
4252
4253                 $res = $dbr->select(
4254                         'categorylinks',
4255                         'cl_to',
4256                         array( 'cl_from' => $titleKey ),
4257                         __METHOD__
4258                 );
4259
4260                 if ( $res->numRows() > 0 ) {
4261                         foreach ( $res as $row ) {
4262                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4263                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4264                         }
4265                 }
4266                 return $data;
4267         }
4268
4269         /**
4270          * Get a tree of parent categories
4271          *
4272          * @param array $children Array with the children in the keys, to check for circular refs
4273          * @return array Tree of parent categories
4274          */
4275         public function getParentCategoryTree( $children = array() ) {
4276                 $stack = array();
4277                 $parents = $this->getParentCategories();
4278
4279                 if ( $parents ) {
4280                         foreach ( $parents as $parent => $current ) {
4281                                 if ( array_key_exists( $parent, $children ) ) {
4282                                         # Circular reference
4283                                         $stack[$parent] = array();
4284                                 } else {
4285                                         $nt = Title::newFromText( $parent );
4286                                         if ( $nt ) {
4287                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4288                                         }
4289                                 }
4290                         }
4291                 }
4292
4293                 return $stack;
4294         }
4295
4296         /**
4297          * Get an associative array for selecting this title from
4298          * the "page" table
4299          *
4300          * @return array Array suitable for the $where parameter of DB::select()
4301          */
4302         public function pageCond() {
4303                 if ( $this->mArticleID > 0 ) {
4304                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4305                         return array( 'page_id' => $this->mArticleID );
4306                 } else {
4307                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4308                 }
4309         }
4310
4311         /**
4312          * Get the revision ID of the previous revision
4313          *
4314          * @param int $revId Revision ID. Get the revision that was before this one.
4315          * @param int $flags Title::GAID_FOR_UPDATE
4316          * @return int|bool Old revision ID, or false if none exists
4317          */
4318         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4319                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4320                 $revId = $db->selectField( 'revision', 'rev_id',
4321                         array(
4322                                 'rev_page' => $this->getArticleID( $flags ),
4323                                 'rev_id < ' . intval( $revId )
4324                         ),
4325                         __METHOD__,
4326                         array( 'ORDER BY' => 'rev_id DESC' )
4327                 );
4328
4329                 if ( $revId === false ) {
4330                         return false;
4331                 } else {
4332                         return intval( $revId );
4333                 }
4334         }
4335
4336         /**
4337          * Get the revision ID of the next revision
4338          *
4339          * @param int $revId Revision ID. Get the revision that was after this one.
4340          * @param int $flags Title::GAID_FOR_UPDATE
4341          * @return int|bool Next revision ID, or false if none exists
4342          */
4343         public function getNextRevisionID( $revId, $flags = 0 ) {
4344                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4345                 $revId = $db->selectField( 'revision', 'rev_id',
4346                         array(
4347                                 'rev_page' => $this->getArticleID( $flags ),
4348                                 'rev_id > ' . intval( $revId )
4349                         ),
4350                         __METHOD__,
4351                         array( 'ORDER BY' => 'rev_id' )
4352                 );
4353
4354                 if ( $revId === false ) {
4355                         return false;
4356                 } else {
4357                         return intval( $revId );
4358                 }
4359         }
4360
4361         /**
4362          * Get the first revision of the page
4363          *
4364          * @param int $flags Title::GAID_FOR_UPDATE
4365          * @return Revision|null If page doesn't exist
4366          */
4367         public function getFirstRevision( $flags = 0 ) {
4368                 $pageId = $this->getArticleID( $flags );
4369                 if ( $pageId ) {
4370                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4371                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4372                                 array( 'rev_page' => $pageId ),
4373                                 __METHOD__,
4374                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4375                         );
4376                         if ( $row ) {
4377                                 return new Revision( $row );
4378                         }
4379                 }
4380                 return null;
4381         }
4382
4383         /**
4384          * Get the oldest revision timestamp of this page
4385          *
4386          * @param int $flags Title::GAID_FOR_UPDATE
4387          * @return string MW timestamp
4388          */
4389         public function getEarliestRevTime( $flags = 0 ) {
4390                 $rev = $this->getFirstRevision( $flags );
4391                 return $rev ? $rev->getTimestamp() : null;
4392         }
4393
4394         /**
4395          * Check if this is a new page
4396          *
4397          * @return bool
4398          */
4399         public function isNewPage() {
4400                 $dbr = wfGetDB( DB_SLAVE );
4401                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4402         }
4403
4404         /**
4405          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4406          *
4407          * @return bool
4408          */
4409         public function isBigDeletion() {
4410                 global $wgDeleteRevisionsLimit;
4411
4412                 if ( !$wgDeleteRevisionsLimit ) {
4413                         return false;
4414                 }
4415
4416                 $revCount = $this->estimateRevisionCount();
4417                 return $revCount > $wgDeleteRevisionsLimit;
4418         }
4419
4420         /**
4421          * Get the  approximate revision count of this page.
4422          *
4423          * @return int
4424          */
4425         public function estimateRevisionCount() {
4426                 if ( !$this->exists() ) {
4427                         return 0;
4428                 }
4429
4430                 if ( $this->mEstimateRevisions === null ) {
4431                         $dbr = wfGetDB( DB_SLAVE );
4432                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4433                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4434                 }
4435
4436                 return $this->mEstimateRevisions;
4437         }
4438
4439         /**
4440          * Get the number of revisions between the given revision.
4441          * Used for diffs and other things that really need it.
4442          *
4443          * @param int|Revision $old Old revision or rev ID (first before range)
4444          * @param int|Revision $new New revision or rev ID (first after range)
4445          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4446          * @return int Number of revisions between these revisions.
4447          */
4448         public function countRevisionsBetween( $old, $new, $max = null ) {
4449                 if ( !( $old instanceof Revision ) ) {
4450                         $old = Revision::newFromTitle( $this, (int)$old );
4451                 }
4452                 if ( !( $new instanceof Revision ) ) {
4453                         $new = Revision::newFromTitle( $this, (int)$new );
4454                 }
4455                 if ( !$old || !$new ) {
4456                         return 0; // nothing to compare
4457                 }
4458                 $dbr = wfGetDB( DB_SLAVE );
4459                 $conds = array(
4460                         'rev_page' => $this->getArticleID(),
4461                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4462                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4463                 );
4464                 if ( $max !== null ) {
4465                         $res = $dbr->select( 'revision', '1',
4466                                 $conds,
4467                                 __METHOD__,
4468                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4469                         );
4470                         return $res->numRows();
4471                 } else {
4472                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4473                 }
4474         }
4475
4476         /**
4477          * Get the authors between the given revisions or revision IDs.
4478          * Used for diffs and other things that really need it.
4479          *
4480          * @since 1.23
4481          *
4482          * @param int|Revision $old Old revision or rev ID (first before range by default)
4483          * @param int|Revision $new New revision or rev ID (first after range by default)
4484          * @param int $limit Maximum number of authors
4485          * @param string|array $options (Optional): Single option, or an array of options:
4486          *     'include_old' Include $old in the range; $new is excluded.
4487          *     'include_new' Include $new in the range; $old is excluded.
4488          *     'include_both' Include both $old and $new in the range.
4489          *     Unknown option values are ignored.
4490          * @return array|null Names of revision authors in the range; null if not both revisions exist
4491          */
4492         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4493                 if ( !( $old instanceof Revision ) ) {
4494                         $old = Revision::newFromTitle( $this, (int)$old );
4495                 }
4496                 if ( !( $new instanceof Revision ) ) {
4497                         $new = Revision::newFromTitle( $this, (int)$new );
4498                 }
4499                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4500                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4501                 // in the sanity check below?
4502                 if ( !$old || !$new ) {
4503                         return null; // nothing to compare
4504                 }
4505                 $authors = array();
4506                 $old_cmp = '>';
4507                 $new_cmp = '<';
4508                 $options = (array)$options;
4509                 if ( in_array( 'include_old', $options ) ) {
4510                         $old_cmp = '>=';
4511                 }
4512                 if ( in_array( 'include_new', $options ) ) {
4513                         $new_cmp = '<=';
4514                 }
4515                 if ( in_array( 'include_both', $options ) ) {
4516                         $old_cmp = '>=';
4517                         $new_cmp = '<=';
4518                 }
4519                 // No DB query needed if $old and $new are the same or successive revisions:
4520                 if ( $old->getId() === $new->getId() ) {
4521                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? array() : array( $old->getRawUserText() );
4522                 } elseif ( $old->getId() === $new->getParentId() ) {
4523                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4524                                 $authors[] = $old->getRawUserText();
4525                                 if ( $old->getRawUserText() != $new->getRawUserText() ) {
4526                                         $authors[] = $new->getRawUserText();
4527                                 }
4528                         } elseif ( $old_cmp === '>=' ) {
4529                                 $authors[] = $old->getRawUserText();
4530                         } elseif ( $new_cmp === '<=' ) {
4531                                 $authors[] = $new->getRawUserText();
4532                         }
4533                         return $authors;
4534                 }
4535                 $dbr = wfGetDB( DB_SLAVE );
4536                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4537                         array(
4538                                 'rev_page' => $this->getArticleID(),
4539                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4540                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4541                         ), __METHOD__,
4542                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4543                 );
4544                 foreach ( $res as $row ) {
4545                         $authors[] = $row->rev_user_text;
4546                 }
4547                 return $authors;
4548         }
4549
4550         /**
4551          * Get the number of authors between the given revisions or revision IDs.
4552          * Used for diffs and other things that really need it.
4553          *
4554          * @param int|Revision $old Old revision or rev ID (first before range by default)
4555          * @param int|Revision $new New revision or rev ID (first after range by default)
4556          * @param int $limit Maximum number of authors
4557          * @param string|array $options (Optional): Single option, or an array of options:
4558          *     'include_old' Include $old in the range; $new is excluded.
4559          *     'include_new' Include $new in the range; $old is excluded.
4560          *     'include_both' Include both $old and $new in the range.
4561          *     Unknown option values are ignored.
4562          * @return int Number of revision authors in the range; zero if not both revisions exist
4563          */
4564         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4565                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4566                 return $authors ? count( $authors ) : 0;
4567         }
4568
4569         /**
4570          * Compare with another title.
4571          *
4572          * @param Title $title
4573          * @return bool
4574          */
4575         public function equals( Title $title ) {
4576                 // Note: === is necessary for proper matching of number-like titles.
4577                 return $this->getInterwiki() === $title->getInterwiki()
4578                         && $this->getNamespace() == $title->getNamespace()
4579                         && $this->getDBkey() === $title->getDBkey();
4580         }
4581
4582         /**
4583          * Check if this title is a subpage of another title
4584          *
4585          * @param Title $title
4586          * @return bool
4587          */
4588         public function isSubpageOf( Title $title ) {
4589                 return $this->getInterwiki() === $title->getInterwiki()
4590                         && $this->getNamespace() == $title->getNamespace()
4591                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4592         }
4593
4594         /**
4595          * Check if page exists.  For historical reasons, this function simply
4596          * checks for the existence of the title in the page table, and will
4597          * thus return false for interwiki links, special pages and the like.
4598          * If you want to know if a title can be meaningfully viewed, you should
4599          * probably call the isKnown() method instead.
4600          *
4601          * @return bool
4602          */
4603         public function exists() {
4604                 return $this->getArticleID() != 0;
4605         }
4606
4607         /**
4608          * Should links to this title be shown as potentially viewable (i.e. as
4609          * "bluelinks"), even if there's no record by this title in the page
4610          * table?
4611          *
4612          * This function is semi-deprecated for public use, as well as somewhat
4613          * misleadingly named.  You probably just want to call isKnown(), which
4614          * calls this function internally.
4615          *
4616          * (ISSUE: Most of these checks are cheap, but the file existence check
4617          * can potentially be quite expensive.  Including it here fixes a lot of
4618          * existing code, but we might want to add an optional parameter to skip
4619          * it and any other expensive checks.)
4620          *
4621          * @return bool
4622          */
4623         public function isAlwaysKnown() {
4624                 $isKnown = null;
4625
4626                 /**
4627                  * Allows overriding default behavior for determining if a page exists.
4628                  * If $isKnown is kept as null, regular checks happen. If it's
4629                  * a boolean, this value is returned by the isKnown method.
4630                  *
4631                  * @since 1.20
4632                  *
4633                  * @param Title $title
4634                  * @param bool|null $isKnown
4635                  */
4636                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4637
4638                 if ( !is_null( $isKnown ) ) {
4639                         return $isKnown;
4640                 }
4641
4642                 if ( $this->isExternal() ) {
4643                         return true;  // any interwiki link might be viewable, for all we know
4644                 }
4645
4646                 switch ( $this->mNamespace ) {
4647                         case NS_MEDIA:
4648                         case NS_FILE:
4649                                 // file exists, possibly in a foreign repo
4650                                 return (bool)wfFindFile( $this );
4651                         case NS_SPECIAL:
4652                                 // valid special page
4653                                 return SpecialPageFactory::exists( $this->getDBkey() );
4654                         case NS_MAIN:
4655                                 // selflink, possibly with fragment
4656                                 return $this->mDbkeyform == '';
4657                         case NS_MEDIAWIKI:
4658                                 // known system message
4659                                 return $this->hasSourceText() !== false;
4660                         default:
4661                                 return false;
4662                 }
4663         }
4664
4665         /**
4666          * Does this title refer to a page that can (or might) be meaningfully
4667          * viewed?  In particular, this function may be used to determine if
4668          * links to the title should be rendered as "bluelinks" (as opposed to
4669          * "redlinks" to non-existent pages).
4670          * Adding something else to this function will cause inconsistency
4671          * since LinkHolderArray calls isAlwaysKnown() and does its own
4672          * page existence check.
4673          *
4674          * @return bool
4675          */
4676         public function isKnown() {
4677                 return $this->isAlwaysKnown() || $this->exists();
4678         }
4679
4680         /**
4681          * Does this page have source text?
4682          *
4683          * @return bool
4684          */
4685         public function hasSourceText() {
4686                 if ( $this->exists() ) {
4687                         return true;
4688                 }
4689
4690                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4691                         // If the page doesn't exist but is a known system message, default
4692                         // message content will be displayed, same for language subpages-
4693                         // Use always content language to avoid loading hundreds of languages
4694                         // to get the link color.
4695                         global $wgContLang;
4696                         list( $name, ) = MessageCache::singleton()->figureMessage(
4697                                 $wgContLang->lcfirst( $this->getText() )
4698                         );
4699                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4700                         return $message->exists();
4701                 }
4702
4703                 return false;
4704         }
4705
4706         /**
4707          * Get the default message text or false if the message doesn't exist
4708          *
4709          * @return string|bool
4710          */
4711         public function getDefaultMessageText() {
4712                 global $wgContLang;
4713
4714                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4715                         return false;
4716                 }
4717
4718                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4719                         $wgContLang->lcfirst( $this->getText() )
4720                 );
4721                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4722
4723                 if ( $message->exists() ) {
4724                         return $message->plain();
4725                 } else {
4726                         return false;
4727                 }
4728         }
4729
4730         /**
4731          * Updates page_touched for this page; called from LinksUpdate.php
4732          *
4733          * @return bool True if the update succeeded
4734          */
4735         public function invalidateCache() {
4736                 if ( wfReadOnly() ) {
4737                         return false;
4738                 }
4739
4740                 if ( $this->mArticleID === 0 ) {
4741                         return true; // avoid gap locking if we know it's not there
4742                 }
4743
4744                 $method = __METHOD__;
4745                 $dbw = wfGetDB( DB_MASTER );
4746                 $conds = $this->pageCond();
4747                 $dbw->onTransactionIdle( function() use ( $dbw, $conds, $method ) {
4748                         $dbw->update(
4749                                 'page',
4750                                 array( 'page_touched' => $dbw->timestamp() ),
4751                                 $conds,
4752                                 $method
4753                         );
4754                 } );
4755
4756                 return true;
4757         }
4758
4759         /**
4760          * Update page_touched timestamps and send squid purge messages for
4761          * pages linking to this title. May be sent to the job queue depending
4762          * on the number of links. Typically called on create and delete.
4763          */
4764         public function touchLinks() {
4765                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4766                 $u->doUpdate();
4767
4768                 if ( $this->getNamespace() == NS_CATEGORY ) {
4769                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4770                         $u->doUpdate();
4771                 }
4772         }
4773
4774         /**
4775          * Get the last touched timestamp
4776          *
4777          * @param DatabaseBase $db Optional db
4778          * @return string Last-touched timestamp
4779          */
4780         public function getTouched( $db = null ) {
4781                 if ( $db === null ) {
4782                         $db = wfGetDB( DB_SLAVE );
4783                 }
4784                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4785                 return $touched;
4786         }
4787
4788         /**
4789          * Get the timestamp when this page was updated since the user last saw it.
4790          *
4791          * @param User $user
4792          * @return string|null
4793          */
4794         public function getNotificationTimestamp( $user = null ) {
4795                 global $wgUser, $wgShowUpdatedMarker;
4796                 // Assume current user if none given
4797                 if ( !$user ) {
4798                         $user = $wgUser;
4799                 }
4800                 // Check cache first
4801                 $uid = $user->getId();
4802                 // avoid isset here, as it'll return false for null entries
4803                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4804                         return $this->mNotificationTimestamp[$uid];
4805                 }
4806                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4807                         $this->mNotificationTimestamp[$uid] = false;
4808                         return $this->mNotificationTimestamp[$uid];
4809                 }
4810                 // Don't cache too much!
4811                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4812                         $this->mNotificationTimestamp = array();
4813                 }
4814                 $dbr = wfGetDB( DB_SLAVE );
4815                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4816                         'wl_notificationtimestamp',
4817                         array(
4818                                 'wl_user' => $user->getId(),
4819                                 'wl_namespace' => $this->getNamespace(),
4820                                 'wl_title' => $this->getDBkey(),
4821                         ),
4822                         __METHOD__
4823                 );
4824                 return $this->mNotificationTimestamp[$uid];
4825         }
4826
4827         /**
4828          * Generate strings used for xml 'id' names in monobook tabs
4829          *
4830          * @param string $prepend Defaults to 'nstab-'
4831          * @return string XML 'id' name
4832          */
4833         public function getNamespaceKey( $prepend = 'nstab-' ) {
4834                 global $wgContLang;
4835                 // Gets the subject namespace if this title
4836                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4837                 // Checks if canonical namespace name exists for namespace
4838                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4839                         // Uses canonical namespace name
4840                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4841                 } else {
4842                         // Uses text of namespace
4843                         $namespaceKey = $this->getSubjectNsText();
4844                 }
4845                 // Makes namespace key lowercase
4846                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4847                 // Uses main
4848                 if ( $namespaceKey == '' ) {
4849                         $namespaceKey = 'main';
4850                 }
4851                 // Changes file to image for backwards compatibility
4852                 if ( $namespaceKey == 'file' ) {
4853                         $namespaceKey = 'image';
4854                 }
4855                 return $prepend . $namespaceKey;
4856         }
4857
4858         /**
4859          * Get all extant redirects to this Title
4860          *
4861          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4862          * @return Title[] Array of Title redirects to this title
4863          */
4864         public function getRedirectsHere( $ns = null ) {
4865                 $redirs = array();
4866
4867                 $dbr = wfGetDB( DB_SLAVE );
4868                 $where = array(
4869                         'rd_namespace' => $this->getNamespace(),
4870                         'rd_title' => $this->getDBkey(),
4871                         'rd_from = page_id'
4872                 );
4873                 if ( $this->isExternal() ) {
4874                         $where['rd_interwiki'] = $this->getInterwiki();
4875                 } else {
4876                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4877                 }
4878                 if ( !is_null( $ns ) ) {
4879                         $where['page_namespace'] = $ns;
4880                 }
4881
4882                 $res = $dbr->select(
4883                         array( 'redirect', 'page' ),
4884                         array( 'page_namespace', 'page_title' ),
4885                         $where,
4886                         __METHOD__
4887                 );
4888
4889                 foreach ( $res as $row ) {
4890                         $redirs[] = self::newFromRow( $row );
4891                 }
4892                 return $redirs;
4893         }
4894
4895         /**
4896          * Check if this Title is a valid redirect target
4897          *
4898          * @return bool
4899          */
4900         public function isValidRedirectTarget() {
4901                 global $wgInvalidRedirectTargets;
4902
4903                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4904                 if ( $this->isSpecial( 'Userlogout' ) ) {
4905                         return false;
4906                 }
4907
4908                 foreach ( $wgInvalidRedirectTargets as $target ) {
4909                         if ( $this->isSpecial( $target ) ) {
4910                                 return false;
4911                         }
4912                 }
4913
4914                 return true;
4915         }
4916
4917         /**
4918          * Get a backlink cache object
4919          *
4920          * @return BacklinkCache
4921          */
4922         public function getBacklinkCache() {
4923                 return BacklinkCache::get( $this );
4924         }
4925
4926         /**
4927          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4928          *
4929          * @return bool
4930          */
4931         public function canUseNoindex() {
4932                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4933
4934                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4935                         ? $wgContentNamespaces
4936                         : $wgExemptFromUserRobotsControl;
4937
4938                 return !in_array( $this->mNamespace, $bannedNamespaces );
4939
4940         }
4941
4942         /**
4943          * Returns the raw sort key to be used for categories, with the specified
4944          * prefix.  This will be fed to Collation::getSortKey() to get a
4945          * binary sortkey that can be used for actual sorting.
4946          *
4947          * @param string $prefix The prefix to be used, specified using
4948          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4949          *   prefix.
4950          * @return string
4951          */
4952         public function getCategorySortkey( $prefix = '' ) {
4953                 $unprefixed = $this->getText();
4954
4955                 // Anything that uses this hook should only depend
4956                 // on the Title object passed in, and should probably
4957                 // tell the users to run updateCollations.php --force
4958                 // in order to re-sort existing category relations.
4959                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4960                 if ( $prefix !== '' ) {
4961                         # Separate with a line feed, so the unprefixed part is only used as
4962                         # a tiebreaker when two pages have the exact same prefix.
4963                         # In UCA, tab is the only character that can sort above LF
4964                         # so we strip both of them from the original prefix.
4965                         $prefix = strtr( $prefix, "\n\t", '  ' );
4966                         return "$prefix\n$unprefixed";
4967                 }
4968                 return $unprefixed;
4969         }
4970
4971         /**
4972          * Get the language in which the content of this page is written in
4973          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4974          * e.g. $wgLang (such as special pages, which are in the user language).
4975          *
4976          * @since 1.18
4977          * @return Language
4978          */
4979         public function getPageLanguage() {
4980                 global $wgLang, $wgLanguageCode;
4981                 wfProfileIn( __METHOD__ );
4982                 if ( $this->isSpecialPage() ) {
4983                         // special pages are in the user language
4984                         wfProfileOut( __METHOD__ );
4985                         return $wgLang;
4986                 }
4987
4988                 // Checking if DB language is set
4989                 if ( $this->mDbPageLanguage ) {
4990                         wfProfileOut( __METHOD__ );
4991                         return wfGetLangObj( $this->mDbPageLanguage );
4992                 }
4993
4994                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4995                         // Note that this may depend on user settings, so the cache should
4996                         // be only per-request.
4997                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4998                         // content to determine the page language!
4999                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
5000                         // tests.
5001                         $contentHandler = ContentHandler::getForTitle( $this );
5002                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
5003                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
5004                 } else {
5005                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
5006                 }
5007
5008                 wfProfileOut( __METHOD__ );
5009                 return $langObj;
5010         }
5011
5012         /**
5013          * Get the language in which the content of this page is written when
5014          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
5015          * e.g. $wgLang (such as special pages, which are in the user language).
5016          *
5017          * @since 1.20
5018          * @return Language
5019          */
5020         public function getPageViewLanguage() {
5021                 global $wgLang;
5022
5023                 if ( $this->isSpecialPage() ) {
5024                         // If the user chooses a variant, the content is actually
5025                         // in a language whose code is the variant code.
5026                         $variant = $wgLang->getPreferredVariant();
5027                         if ( $wgLang->getCode() !== $variant ) {
5028                                 return Language::factory( $variant );
5029                         }
5030
5031                         return $wgLang;
5032                 }
5033
5034                 // @note Can't be cached persistently, depends on user settings.
5035                 // @note ContentHandler::getPageViewLanguage() may need to load the
5036                 //   content to determine the page language!
5037                 $contentHandler = ContentHandler::getForTitle( $this );
5038                 $pageLang = $contentHandler->getPageViewLanguage( $this );
5039                 return $pageLang;
5040         }
5041
5042         /**
5043          * Get a list of rendered edit notices for this page.
5044          *
5045          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
5046          * they will already be wrapped in paragraphs.
5047          *
5048          * @since 1.21
5049          * @param int $oldid Revision ID that's being edited
5050          * @return array
5051          */
5052         public function getEditNotices( $oldid = 0 ) {
5053                 $notices = array();
5054
5055                 # Optional notices on a per-namespace and per-page basis
5056                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
5057                 $editnotice_ns_message = wfMessage( $editnotice_ns );
5058                 if ( $editnotice_ns_message->exists() ) {
5059                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
5060                 }
5061                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
5062                         $parts = explode( '/', $this->getDBkey() );
5063                         $editnotice_base = $editnotice_ns;
5064                         while ( count( $parts ) > 0 ) {
5065                                 $editnotice_base .= '-' . array_shift( $parts );
5066                                 $editnotice_base_msg = wfMessage( $editnotice_base );
5067                                 if ( $editnotice_base_msg->exists() ) {
5068                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
5069                                 }
5070                         }
5071                 } else {
5072                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
5073                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
5074                         $editnoticeMsg = wfMessage( $editnoticeText );
5075                         if ( $editnoticeMsg->exists() ) {
5076                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
5077                         }
5078                 }
5079
5080                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
5081                 return $notices;
5082         }
5083 }