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