includes/Title.php

   1 <?php
   2 /**
   3  * See title.txt
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 /**
  24  * Represents a title within MediaWiki.
  25  * Optionally may contain an interwiki designation or namespace.
  26  * @note This class can fetch various kinds of data from the database;
  27  *       however, it does so inefficiently.
  28  *
  29  * @internal documentation reviewed 15 Mar 2010
  30  */
  31 class Title {
  32         /** @name Static cache variables */
  33         // @{
  34         static private $titleCache = array();
  35         // @}
  36
  37         /**
  38          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  39          * commonly used titles. On a batch operation this can become a memory leak
  40          * if not bounded. After hitting this many titles reset the cache.
  41          */
  42         const CACHE_MAX = 1000;
  43
  44         /**
  45          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  46          * to use the master DB
  47          */
  48         const GAID_FOR_UPDATE = 1;
  49
  50
  51         /**
  52          * @name Private member variables
  53          * Please use the accessor functions instead.
  54          * @private
  55          */
  56         // @{
  57
  58         var $mTextform = '';              // /< Text form (spaces not underscores) of the main part
  59         var $mUrlform = '';               // /< URL-encoded form of the main part
  60         var $mDbkeyform = '';             // /< Main part with underscores
  61         var $mUserCaseDBKey;              // /< DB key with the initial letter in the case specified by the user
  62         var $mNamespace = NS_MAIN;        // /< Namespace index, i.e. one of the NS_xxxx constants
  63         var $mInterwiki = '';             // /< Interwiki prefix (or null string)
  64         var $mFragment;                   // /< Title fragment (i.e. the bit after the #)
  65         var $mArticleID = -1;             // /< Article ID, fetched from the link cache on demand
  66         var $mLatestID = false;           // /< ID of most recent revision
  67         var $mRestrictions = array();     // /< Array of groups allowed to edit this article
  68         var $mOldRestrictions = false;
  69         var $mCascadeRestriction;         ///< Cascade restrictions on this page to included templates and images?
  70         var $mCascadingRestrictions;      // Caching the results of getCascadeProtectionSources
  71         var $mRestrictionsExpiry = array(); ///< When do the restrictions on this page expire?
  72         var $mHasCascadingRestrictions;   ///< Are cascading restrictions in effect on this page?
  73         var $mCascadeSources;             ///< Where are the cascading restrictions coming from on this page?
  74         var $mRestrictionsLoaded = false; ///< Boolean for initialisation on demand
  75         var $mPrefixedText;               ///< Text form including namespace/interwiki, initialised on demand
  76         var $mTitleProtection;            ///< Cached value for getTitleProtection (create protection)
  77         # Don't change the following default, NS_MAIN is hardcoded in several
  78         # places.  See bug 696.
  79         var $mDefaultNamespace = NS_MAIN; // /< Namespace index when there is no namespace
  80                                                                           # Zero except in {{transclusion}} tags
  81         var $mWatched = null;             // /< Is $wgUser watching this page? null if unfilled, accessed through userIsWatching()
  82         var $mLength = -1;                // /< The page length, 0 for special pages
  83         var $mRedirect = null;            // /< Is the article at this title a redirect?
  84         var $mNotificationTimestamp = array(); // /< Associative array of user ID -> timestamp/false
  85         var $mBacklinkCache = null;       // /< Cache of links to this title
  86         // @}
  87
  88
  89         /**
  90          * Constructor
  91          */
  92         /*protected*/ function __construct() { }
  93
  94         /**
  95          * Create a new Title from a prefixed DB key
  96          *
  97          * @param $key String the database key, which has underscores
  98          *      instead of spaces, possibly including namespace and
  99          *      interwiki prefixes
 100          * @return Title, or NULL on an error
 101          */
 102         public static function newFromDBkey( $key ) {
 103                 $t = new Title();
 104                 $t->mDbkeyform = $key;
 105                 if ( $t->secureAndSplit() ) {
 106                         return $t;
 107                 } else {
 108                         return null;
 109                 }
 110         }
 111
 112         /**
 113          * Create a new Title from text, such as what one would find in a link. De-
 114          * codes any HTML entities in the text.
 115          *
 116          * @param $text String the link text; spaces, prefixes, and an
 117          *   initial ':' indicating the main namespace are accepted.
 118          * @param $defaultNamespace Int the namespace to use if none is speci-
 119          *   fied by a prefix.  If you want to force a specific namespace even if
 120          *   $text might begin with a namespace prefix, use makeTitle() or
 121          *   makeTitleSafe().
 122          * @return Title, or null on an error.
 123          */
 124         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 125                 if ( is_object( $text ) ) {
 126                         throw new MWException( 'Title::newFromText given an object' );
 127                 }
 128
 129                 /**
 130                  * Wiki pages often contain multiple links to the same page.
 131                  * Title normalization and parsing can become expensive on
 132                  * pages with many links, so we can save a little time by
 133                  * caching them.
 134                  *
 135                  * In theory these are value objects and won't get changed...
 136                  */
 137                 if ( $defaultNamespace == NS_MAIN && isset( Title::$titleCache[$text] ) ) {
 138                         return Title::$titleCache[$text];
 139                 }
 140
 141                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 142                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 143
 144                 $t = new Title();
 145                 $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
 146                 $t->mDefaultNamespace = $defaultNamespace;
 147
 148                 static $cachedcount = 0 ;
 149                 if ( $t->secureAndSplit() ) {
 150                         if ( $defaultNamespace == NS_MAIN ) {
 151                                 if ( $cachedcount >= self::CACHE_MAX ) {
 152                                         # Avoid memory leaks on mass operations...
 153                                         Title::$titleCache = array();
 154                                         $cachedcount = 0;
 155                                 }
 156                                 $cachedcount++;
 157                                 Title::$titleCache[$text] =& $t;
 158                         }
 159                         return $t;
 160                 } else {
 161                         $ret = null;
 162                         return $ret;
 163                 }
 164         }
 165
 166         /**
 167          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 168          *
 169          * Example of wrong and broken code:
 170          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 171          *
 172          * Example of right code:
 173          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 174          *
 175          * Create a new Title from URL-encoded text. Ensures that
 176          * the given title's length does not exceed the maximum.
 177          *
 178          * @param $url String the title, as might be taken from a URL
 179          * @return Title the new object, or NULL on an error
 180          */
 181         public static function newFromURL( $url ) {
 182                 global $wgLegalTitleChars;
 183                 $t = new Title();
 184
 185                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 186                 # but some URLs used it as a space replacement and they still come
 187                 # from some external search tools.
 188                 if ( strpos( $wgLegalTitleChars, '+' ) === false ) {
 189                         $url = str_replace( '+', ' ', $url );
 190                 }
 191
 192                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 193                 if ( $t->secureAndSplit() ) {
 194                         return $t;
 195                 } else {
 196                         return null;
 197                 }
 198         }
 199
 200         /**
 201          * Create a new Title from an article ID
 202          *
 203          * @param $id Int the page_id corresponding to the Title to create
 204          * @param $flags Int use Title::GAID_FOR_UPDATE to use master
 205          * @return Title the new object, or NULL on an error
 206          */
 207         public static function newFromID( $id, $flags = 0 ) {
 208                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 209                 $row = $db->selectRow( 'page', '*', array( 'page_id' => $id ), __METHOD__ );
 210                 if ( $row !== false ) {
 211                         $title = Title::newFromRow( $row );
 212                 } else {
 213                         $title = null;
 214                 }
 215                 return $title;
 216         }
 217
 218         /**
 219          * Make an array of titles from an array of IDs
 220          *
 221          * @param $ids Array of Int Array of IDs
 222          * @return Array of Titles
 223          */
 224         public static function newFromIDs( $ids ) {
 225                 if ( !count( $ids ) ) {
 226                         return array();
 227                 }
 228                 $dbr = wfGetDB( DB_SLAVE );
 229
 230                 $res = $dbr->select(
 231                         'page',
 232                         array(
 233                                 'page_namespace', 'page_title', 'page_id',
 234                                 'page_len', 'page_is_redirect', 'page_latest',
 235                         ),
 236                         array( 'page_id' => $ids ),
 237                         __METHOD__
 238                 );
 239
 240                 $titles = array();
 241                 foreach ( $res as $row ) {
 242                         $titles[] = Title::newFromRow( $row );
 243                 }
 244                 return $titles;
 245         }
 246
 247         /**
 248          * Make a Title object from a DB row
 249          *
 250          * @param $row Object database row (needs at least page_title,page_namespace)
 251          * @return Title corresponding Title
 252          */
 253         public static function newFromRow( $row ) {
 254                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 255                 $t->loadFromRow( $row );
 256                 return $t;
 257         }
 258
 259         /**
 260          * Load Title object fields from a DB row.
 261          * If false is given, the title will be treated as non-existing.
 262          *
 263          * @param $row Object|false database row
 264          * @return void
 265          */
 266         public function loadFromRow( $row ) {
 267                 if ( $row ) { // page found
 268                         if ( isset( $row->page_id ) )
 269                                 $this->mArticleID = (int)$row->page_id;
 270                         if ( isset( $row->page_len ) )
 271                                 $this->mLength = (int)$row->page_len;
 272                         if ( isset( $row->page_is_redirect ) )
 273                                 $this->mRedirect = (bool)$row->page_is_redirect;
 274                         if ( isset( $row->page_latest ) )
 275                                 $this->mLatestID = (int)$row->page_latest;
 276                 } else { // page not found
 277                         $this->mArticleID = 0;
 278                         $this->mLength = 0;
 279                         $this->mRedirect = false;
 280                         $this->mLatestID = 0;
 281                 }
 282         }
 283
 284         /**
 285          * Create a new Title from a namespace index and a DB key.
 286          * It's assumed that $ns and $title are *valid*, for instance when
 287          * they came directly from the database or a special page name.
 288          * For convenience, spaces are converted to underscores so that
 289          * eg user_text fields can be used directly.
 290          *
 291          * @param $ns Int the namespace of the article
 292          * @param $title String the unprefixed database key form
 293          * @param $fragment String the link fragment (after the "#")
 294          * @param $interwiki String the interwiki prefix
 295          * @return Title the new object
 296          */
 297         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 298                 $t = new Title();
 299                 $t->mInterwiki = $interwiki;
 300                 $t->mFragment = $fragment;
 301                 $t->mNamespace = $ns = intval( $ns );
 302                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 303                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 304                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 305                 $t->mTextform = str_replace( '_', ' ', $title );
 306                 return $t;
 307         }
 308
 309         /**
 310          * Create a new Title from a namespace index and a DB key.
 311          * The parameters will be checked for validity, which is a bit slower
 312          * than makeTitle() but safer for user-provided data.
 313          *
 314          * @param $ns Int the namespace of the article
 315          * @param $title String database key form
 316          * @param $fragment String the link fragment (after the "#")
 317          * @param $interwiki String interwiki prefix
 318          * @return Title the new object, or NULL on an error
 319          */
 320         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 321                 $t = new Title();
 322                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 323                 if ( $t->secureAndSplit() ) {
 324                         return $t;
 325                 } else {
 326                         return null;
 327                 }
 328         }
 329
 330         /**
 331          * Create a new Title for the Main Page
 332          *
 333          * @return Title the new object
 334          */
 335         public static function newMainPage() {
 336                 $title = Title::newFromText( wfMsgForContent( 'mainpage' ) );
 337                 // Don't give fatal errors if the message is broken
 338                 if ( !$title ) {
 339                         $title = Title::newFromText( 'Main Page' );
 340                 }
 341                 return $title;
 342         }
 343
 344         /**
 345          * Extract a redirect destination from a string and return the
 346          * Title, or null if the text doesn't contain a valid redirect
 347          * This will only return the very next target, useful for
 348          * the redirect table and other checks that don't need full recursion
 349          *
 350          * @param $text String: Text with possible redirect
 351          * @return Title: The corresponding Title
 352          */
 353         public static function newFromRedirect( $text ) {
 354                 return self::newFromRedirectInternal( $text );
 355         }
 356
 357         /**
 358          * Extract a redirect destination from a string and return the
 359          * Title, or null if the text doesn't contain a valid redirect
 360          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 361          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 362          *
 363          * @param $text String Text with possible redirect
 364          * @return Title
 365          */
 366         public static function newFromRedirectRecurse( $text ) {
 367                 $titles = self::newFromRedirectArray( $text );
 368                 return $titles ? array_pop( $titles ) : null;
 369         }
 370
 371         /**
 372          * Extract a redirect destination from a string and return an
 373          * array of Titles, or null if the text doesn't contain a valid redirect
 374          * The last element in the array is the final destination after all redirects
 375          * have been resolved (up to $wgMaxRedirects times)
 376          *
 377          * @param $text String Text with possible redirect
 378          * @return Array of Titles, with the destination last
 379          */
 380         public static function newFromRedirectArray( $text ) {
 381                 global $wgMaxRedirects;
 382                 $title = self::newFromRedirectInternal( $text );
 383                 if ( is_null( $title ) ) {
 384                         return null;
 385                 }
 386                 // recursive check to follow double redirects
 387                 $recurse = $wgMaxRedirects;
 388                 $titles = array( $title );
 389                 while ( --$recurse > 0 ) {
 390                         if ( $title->isRedirect() ) {
 391                                 $article = new Article( $title, 0 );
 392                                 $newtitle = $article->getRedirectTarget();
 393                         } else {
 394                                 break;
 395                         }
 396                         // Redirects to some special pages are not permitted
 397                         if ( $newtitle instanceOf Title && $newtitle->isValidRedirectTarget() ) {
 398                                 // the new title passes the checks, so make that our current title so that further recursion can be checked
 399                                 $title = $newtitle;
 400                                 $titles[] = $newtitle;
 401                         } else {
 402                                 break;
 403                         }
 404                 }
 405                 return $titles;
 406         }
 407
 408         /**
 409          * Really extract the redirect destination
 410          * Do not call this function directly, use one of the newFromRedirect* functions above
 411          *
 412          * @param $text String Text with possible redirect
 413          * @return Title
 414          */
 415         protected static function newFromRedirectInternal( $text ) {
 416                 global $wgMaxRedirects;
 417                 if ( $wgMaxRedirects < 1 ) {
 418                         //redirects are disabled, so quit early
 419                         return null;
 420                 }
 421                 $redir = MagicWord::get( 'redirect' );
 422                 $text = trim( $text );
 423                 if ( $redir->matchStartAndRemove( $text ) ) {
 424                         // Extract the first link and see if it's usable
 425                         // Ensure that it really does come directly after #REDIRECT
 426                         // Some older redirects included a colon, so don't freak about that!
 427                         $m = array();
 428                         if ( preg_match( '!^\s*:?\s*\[{2}(.*?)(?:\|.*?)?\]{2}!', $text, $m ) ) {
 429                                 // Strip preceding colon used to "escape" categories, etc.
 430                                 // and URL-decode links
 431                                 if ( strpos( $m[1], '%' ) !== false ) {
 432                                         // Match behavior of inline link parsing here;
 433                                         $m[1] = rawurldecode( ltrim( $m[1], ':' ) );
 434                                 }
 435                                 $title = Title::newFromText( $m[1] );
 436                                 // If the title is a redirect to bad special pages or is invalid, return null
 437                                 if ( !$title instanceof Title || !$title->isValidRedirectTarget() ) {
 438                                         return null;
 439                                 }
 440                                 return $title;
 441                         }
 442                 }
 443                 return null;
 444         }
 445
 446 # ----------------------------------------------------------------------------
 447 #       Static functions
 448 # ----------------------------------------------------------------------------
 449
 450         /**
 451          * Get the prefixed DB key associated with an ID
 452          *
 453          * @param $id Int the page_id of the article
 454          * @return Title an object representing the article, or NULL if no such article was found
 455          */
 456         public static function nameOf( $id ) {
 457                 $dbr = wfGetDB( DB_SLAVE );
 458
 459                 $s = $dbr->selectRow(
 460                         'page',
 461                         array( 'page_namespace', 'page_title' ),
 462                         array( 'page_id' => $id ),
 463                         __METHOD__
 464                 );
 465                 if ( $s === false ) {
 466                         return null;
 467                 }
 468
 469                 $n = self::makeName( $s->page_namespace, $s->page_title );
 470                 return $n;
 471         }
 472
 473         /**
 474          * Get a regex character class describing the legal characters in a link
 475          *
 476          * @return String the list of characters, not delimited
 477          */
 478         public static function legalChars() {
 479                 global $wgLegalTitleChars;
 480                 return $wgLegalTitleChars;
 481         }
 482
 483         /**
 484          * Get a string representation of a title suitable for
 485          * including in a search index
 486          *
 487          * @param $ns Int a namespace index
 488          * @param $title String text-form main part
 489          * @return String a stripped-down title string ready for the search index
 490          */
 491         public static function indexTitle( $ns, $title ) {
 492                 global $wgContLang;
 493
 494                 $lc = SearchEngine::legalSearchChars() . '&#;';
 495                 $t = $wgContLang->normalizeForSearch( $title );
 496                 $t = preg_replace( "/[^{$lc}]+/", ' ', $t );
 497                 $t = $wgContLang->lc( $t );
 498
 499                 # Handle 's, s'
 500                 $t = preg_replace( "/([{$lc}]+)'s( |$)/", "\\1 \\1's ", $t );
 501                 $t = preg_replace( "/([{$lc}]+)s'( |$)/", "\\1s ", $t );
 502
 503                 $t = preg_replace( "/\\s+/", ' ', $t );
 504
 505                 if ( $ns == NS_FILE ) {
 506                         $t = preg_replace( "/ (png|gif|jpg|jpeg|ogg)$/", "", $t );
 507                 }
 508                 return trim( $t );
 509         }
 510
 511         /**
 512          * Make a prefixed DB key from a DB key and a namespace index
 513          *
 514          * @param $ns Int numerical representation of the namespace
 515          * @param $title String the DB key form the title
 516          * @param $fragment String The link fragment (after the "#")
 517          * @param $interwiki String The interwiki prefix
 518          * @return String the prefixed form of the title
 519          */
 520         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 521                 global $wgContLang;
 522
 523                 $namespace = $wgContLang->getNsText( $ns );
 524                 $name = $namespace == '' ? $title : "$namespace:$title";
 525                 if ( strval( $interwiki ) != '' ) {
 526                         $name = "$interwiki:$name";
 527                 }
 528                 if ( strval( $fragment ) != '' ) {
 529                         $name .= '#' . $fragment;
 530                 }
 531                 return $name;
 532         }
 533
 534         /**
 535          * Determine whether the object refers to a page within
 536          * this project.
 537          *
 538          * @return Bool TRUE if this is an in-project interwiki link or a wikilink, FALSE otherwise
 539          */
 540         public function isLocal() {
 541                 if ( $this->mInterwiki != '' ) {
 542                         return Interwiki::fetch( $this->mInterwiki )->isLocal();
 543                 } else {
 544                         return true;
 545                 }
 546         }
 547
 548         /**
 549          * Determine whether the object refers to a page within
 550          * this project and is transcludable.
 551          *
 552          * @return Bool TRUE if this is transcludable
 553          */
 554         public function isTrans() {
 555                 if ( $this->mInterwiki == '' ) {
 556                         return false;
 557                 }
 558
 559                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 560         }
 561
 562         /**
 563          * Returns the DB name of the distant wiki which owns the object.
 564          *
 565          * @return String the DB name
 566          */
 567         public function getTransWikiID() {
 568                 if ( $this->mInterwiki == '' ) {
 569                         return false;
 570                 }
 571
 572                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 573         }
 574
 575         /**
 576          * Escape a text fragment, say from a link, for a URL
 577          *
 578          * @param $fragment string containing a URL or link fragment (after the "#")
 579          * @return String: escaped string
 580          */
 581         static function escapeFragmentForURL( $fragment ) {
 582                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 583                 # fragments appear not to work in IE (at least up to 7) or in at least
 584                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 585                 # to care if they aren't encoded.
 586                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 587         }
 588
 589 # ----------------------------------------------------------------------------
 590 #       Other stuff
 591 # ----------------------------------------------------------------------------
 592
 593         /** Simple accessors */
 594         /**
 595          * Get the text form (spaces not underscores) of the main part
 596          *
 597          * @return String Main part of the title
 598          */
 599         public function getText() { return $this->mTextform; }
 600
 601         /**
 602          * Get the URL-encoded form of the main part
 603          *
 604          * @return String Main part of the title, URL-encoded
 605          */
 606         public function getPartialURL() { return $this->mUrlform; }
 607
 608         /**
 609          * Get the main part with underscores
 610          *
 611          * @return String: Main part of the title, with underscores
 612          */
 613         public function getDBkey() { return $this->mDbkeyform; }
 614
 615         /**
 616          * Get the namespace index, i.e. one of the NS_xxxx constants.
 617          *
 618          * @return Integer: Namespace index
 619          */
 620         public function getNamespace() { return $this->mNamespace; }
 621
 622         /**
 623          * Get the namespace text
 624          *
 625          * @return String: Namespace text
 626          */
 627         public function getNsText() {
 628                 global $wgContLang;
 629
 630                 if ( $this->mInterwiki != '' ) {
 631                         // This probably shouldn't even happen. ohh man, oh yuck.
 632                         // But for interwiki transclusion it sometimes does.
 633                         // Shit. Shit shit shit.
 634                         //
 635                         // Use the canonical namespaces if possible to try to
 636                         // resolve a foreign namespace.
 637                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 638                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 639                         }
 640                 }
 641
 642                 if ( $wgContLang->needsGenderDistinction() &&
 643                                 MWNamespace::hasGenderDistinction( $this->mNamespace ) ) {
 644                         $gender = GenderCache::singleton()->getGenderOf( $this->getText(), __METHOD__ );
 645                         return $wgContLang->getGenderNsText( $this->mNamespace, $gender );
 646                 }
 647
 648                 return $wgContLang->getNsText( $this->mNamespace );
 649         }
 650
 651         /**
 652          * Get the DB key with the initial letter case as specified by the user
 653          *
 654          * @return String DB key
 655          */
 656         function getUserCaseDBKey() {
 657                 return $this->mUserCaseDBKey;
 658         }
 659
 660         /**
 661          * Get the namespace text of the subject (rather than talk) page
 662          *
 663          * @return String Namespace text
 664          */
 665         public function getSubjectNsText() {
 666                 global $wgContLang;
 667                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 668         }
 669
 670         /**
 671          * Get the namespace text of the talk page
 672          *
 673          * @return String Namespace text
 674          */
 675         public function getTalkNsText() {
 676                 global $wgContLang;
 677                 return( $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) ) );
 678         }
 679
 680         /**
 681          * Could this title have a corresponding talk page?
 682          *
 683          * @return Bool TRUE or FALSE
 684          */
 685         public function canTalk() {
 686                 return( MWNamespace::canTalk( $this->mNamespace ) );
 687         }
 688
 689         /**
 690          * Get the interwiki prefix (or null string)
 691          *
 692          * @return String Interwiki prefix
 693          */
 694         public function getInterwiki() { return $this->mInterwiki; }
 695
 696         /**
 697          * Get the Title fragment (i.e.\ the bit after the #) in text form
 698          *
 699          * @return String Title fragment
 700          */
 701         public function getFragment() { return $this->mFragment; }
 702
 703         /**
 704          * Get the fragment in URL form, including the "#" character if there is one
 705          * @return String Fragment in URL form
 706          */
 707         public function getFragmentForURL() {
 708                 if ( $this->mFragment == '' ) {
 709                         return '';
 710                 } else {
 711                         return '#' . Title::escapeFragmentForURL( $this->mFragment );
 712                 }
 713         }
 714
 715         /**
 716          * Get the default namespace index, for when there is no namespace
 717          *
 718          * @return Int Default namespace index
 719          */
 720         public function getDefaultNamespace() { return $this->mDefaultNamespace; }
 721
 722         /**
 723          * Get title for search index
 724          *
 725          * @return String a stripped-down title string ready for the
 726          *  search index
 727          */
 728         public function getIndexTitle() {
 729                 return Title::indexTitle( $this->mNamespace, $this->mTextform );
 730         }
 731
 732         /**
 733          * Get the prefixed database key form
 734          *
 735          * @return String the prefixed title, with underscores and
 736          *  any interwiki and namespace prefixes
 737          */
 738         public function getPrefixedDBkey() {
 739                 $s = $this->prefix( $this->mDbkeyform );
 740                 $s = str_replace( ' ', '_', $s );
 741                 return $s;
 742         }
 743
 744         /**
 745          * Get the prefixed title with spaces.
 746          * This is the form usually used for display
 747          *
 748          * @return String the prefixed title, with spaces
 749          */
 750         public function getPrefixedText() {
 751                 // @todo FIXME: Bad usage of empty() ?
 752                 if ( empty( $this->mPrefixedText ) ) {
 753                         $s = $this->prefix( $this->mTextform );
 754                         $s = str_replace( '_', ' ', $s );
 755                         $this->mPrefixedText = $s;
 756                 }
 757                 return $this->mPrefixedText;
 758         }
 759
 760         /**
 761          * Get the prefixed title with spaces, plus any fragment
 762          * (part beginning with '#')
 763          *
 764          * @return String the prefixed title, with spaces and the fragment, including '#'
 765          */
 766         public function getFullText() {
 767                 $text = $this->getPrefixedText();
 768                 if ( $this->mFragment != '' ) {
 769                         $text .= '#' . $this->mFragment;
 770                 }
 771                 return $text;
 772         }
 773
 774         /**
 775          * Get the base name, i.e. the leftmost parts before the /
 776          *
 777          * @return String Base name
 778          */
 779         public function getBaseText() {
 780                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
 781                         return $this->getText();
 782                 }
 783
 784                 $parts = explode( '/', $this->getText() );
 785                 # Don't discard the real title if there's no subpage involved
 786                 if ( count( $parts ) > 1 ) {
 787                         unset( $parts[count( $parts ) - 1] );
 788                 }
 789                 return implode( '/', $parts );
 790         }
 791
 792         /**
 793          * Get the lowest-level subpage name, i.e. the rightmost part after /
 794          *
 795          * @return String Subpage name
 796          */
 797         public function getSubpageText() {
 798                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
 799                         return( $this->mTextform );
 800                 }
 801                 $parts = explode( '/', $this->mTextform );
 802                 return( $parts[count( $parts ) - 1] );
 803         }
 804
 805         /**
 806          * Get a URL-encoded form of the subpage text
 807          *
 808          * @return String URL-encoded subpage name
 809          */
 810         public function getSubpageUrlForm() {
 811                 $text = $this->getSubpageText();
 812                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
 813                 return( $text );
 814         }
 815
 816         /**
 817          * Get a URL-encoded title (not an actual URL) including interwiki
 818          *
 819          * @return String the URL-encoded form
 820          */
 821         public function getPrefixedURL() {
 822                 $s = $this->prefix( $this->mDbkeyform );
 823                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
 824                 return $s;
 825         }
 826
 827         /**
 828          * Get a real URL referring to this title, with interwiki link and
 829          * fragment
 830          *
 831          * @param $query \twotypes{\string,\array} an optional query string, not used for interwiki
 832          *   links. Can be specified as an associative array as well, e.g.,
 833          *   array( 'action' => 'edit' ) (keys and values will be URL-escaped).
 834          * @param $variant String language variant of url (for sr, zh..)
 835          * @return String the URL
 836          */
 837         public function getFullURL( $query = '', $variant = false ) {
 838                 global $wgServer, $wgRequest;
 839
 840                 if ( is_array( $query ) ) {
 841                         $query = wfArrayToCGI( $query );
 842                 }
 843
 844                 $interwiki = Interwiki::fetch( $this->mInterwiki );
 845                 if ( !$interwiki ) {
 846                         $url = $this->getLocalURL( $query, $variant );
 847
 848                         // Ugly quick hack to avoid duplicate prefixes (bug 4571 etc)
 849                         // Correct fix would be to move the prepending elsewhere.
 850                         if ( $wgRequest->getVal( 'action' ) != 'render' ) {
 851                                 $url = $wgServer . $url;
 852                         }
 853                 } else {
 854                         $baseUrl = $interwiki->getURL();
 855
 856                         $namespace = wfUrlencode( $this->getNsText() );
 857                         if ( $namespace != '' ) {
 858                                 # Can this actually happen? Interwikis shouldn't be parsed.
 859                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
 860                                 $namespace .= ':';
 861                         }
 862                         $url = str_replace( '$1', $namespace . $this->mUrlform, $baseUrl );
 863                         $url = wfAppendQuery( $url, $query );
 864                 }
 865
 866                 # Finally, add the fragment.
 867                 $url .= $this->getFragmentForURL();
 868
 869                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
 870                 return $url;
 871         }
 872
 873         /**
 874          * Get a URL with no fragment or server name.  If this page is generated
 875          * with action=render, $wgServer is prepended.
 876          *
 877          * @param $query Mixed: an optional query string; if not specified,
 878          *   $wgArticlePath will be used.  Can be specified as an associative array
 879          *   as well, e.g., array( 'action' => 'edit' ) (keys and values will be
 880          *   URL-escaped).
 881          * @param $variant String language variant of url (for sr, zh..)
 882          * @return String the URL
 883          */
 884         public function getLocalURL( $query = '', $variant = false ) {
 885                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
 886                 global $wgVariantArticlePath, $wgContLang;
 887
 888                 if ( is_array( $query ) ) {
 889                         $query = wfArrayToCGI( $query );
 890                 }
 891
 892                 if ( $this->isExternal() ) {
 893                         $url = $this->getFullURL();
 894                         if ( $query ) {
 895                                 // This is currently only used for edit section links in the
 896                                 // context of interwiki transclusion. In theory we should
 897                                 // append the query to the end of any existing query string,
 898                                 // but interwiki transclusion is already broken in that case.
 899                                 $url .= "?$query";
 900                         }
 901                 } else {
 902                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
 903                         if ( $query == '' ) {
 904                                 if ( $variant != false && $wgContLang->hasVariants() ) {
 905                                         if ( !$wgVariantArticlePath ) {
 906                                                 $variantArticlePath =  "$wgScript?title=$1&variant=$2"; // default
 907                                         } else {
 908                                                 $variantArticlePath = $wgVariantArticlePath;
 909                                         }
 910                                         $url = str_replace( '$2', urlencode( $variant ), $variantArticlePath );
 911                                         $url = str_replace( '$1', $dbkey, $url  );
 912                                 } else {
 913                                         $url = str_replace( '$1', $dbkey, $wgArticlePath );
 914                                 }
 915                         } else {
 916                                 global $wgActionPaths;
 917                                 $url = false;
 918                                 $matches = array();
 919                                 if ( !empty( $wgActionPaths ) &&
 920                                         preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches ) )
 921                                 {
 922                                         $action = urldecode( $matches[2] );
 923                                         if ( isset( $wgActionPaths[$action] ) ) {
 924                                                 $query = $matches[1];
 925                                                 if ( isset( $matches[4] ) ) {
 926                                                         $query .= $matches[4];
 927                                                 }
 928                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
 929                                                 if ( $query != '' ) {
 930                                                         $url = wfAppendQuery( $url, $query );
 931                                                 }
 932                                         }
 933                                 }
 934
 935                                 if ( $url === false ) {
 936                                         if ( $query == '-' ) {
 937                                                 $query = '';
 938                                         }
 939                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
 940                                 }
 941                         }
 942
 943                         // @todo FIXME: This causes breakage in various places when we
 944                         // actually expected a local URL and end up with dupe prefixes.
 945                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
 946                                 $url = $wgServer . $url;
 947                         }
 948                 }
 949                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
 950                 return $url;
 951         }
 952
 953         /**
 954          * Get a URL that's the simplest URL that will be valid to link, locally,
 955          * to the current Title.  It includes the fragment, but does not include
 956          * the server unless action=render is used (or the link is external).  If
 957          * there's a fragment but the prefixed text is empty, we just return a link
 958          * to the fragment.
 959          *
 960          * The result obviously should not be URL-escaped, but does need to be
 961          * HTML-escaped if it's being output in HTML.
 962          *
 963          * @param $query Array of Strings An associative array of key => value pairs for the
 964          *   query string.  Keys and values will be escaped.
 965          * @param $variant String language variant of URL (for sr, zh..).  Ignored
 966          *   for external links.  Default is "false" (same variant as current page,
 967          *   for anonymous users).
 968          * @return String the URL
 969          */
 970         public function getLinkUrl( $query = array(), $variant = false ) {
 971                 wfProfileIn( __METHOD__ );
 972                 if ( $this->isExternal() ) {
 973                         $ret = $this->getFullURL( $query );
 974                 } elseif ( $this->getPrefixedText() === '' && $this->getFragment() !== '' ) {
 975                         $ret = $this->getFragmentForURL();
 976                 } else {
 977                         $ret = $this->getLocalURL( $query, $variant ) . $this->getFragmentForURL();
 978                 }
 979                 wfProfileOut( __METHOD__ );
 980                 return $ret;
 981         }
 982
 983         /**
 984          * Get an HTML-escaped version of the URL form, suitable for
 985          * using in a link, without a server name or fragment
 986          *
 987          * @param $query String an optional query string
 988          * @return String the URL
 989          */
 990         public function escapeLocalURL( $query = '' ) {
 991                 return htmlspecialchars( $this->getLocalURL( $query ) );
 992         }
 993
 994         /**
 995          * Get an HTML-escaped version of the URL form, suitable for
 996          * using in a link, including the server name and fragment
 997          *
 998          * @param $query String an optional query string
 999          * @return String the URL
1000          */
1001         public function escapeFullURL( $query = '' ) {
1002                 return htmlspecialchars( $this->getFullURL( $query ) );
1003         }
1004
1005         /**
1006          * Get the URL form for an internal link.
1007          * - Used in various Squid-related code, in case we have a different
1008          * internal hostname for the server from the exposed one.
1009          *
1010          * @param $query String an optional query string
1011          * @param $variant String language variant of url (for sr, zh..)
1012          * @return String the URL
1013          */
1014         public function getInternalURL( $query = '', $variant = false ) {
1015                 global $wgInternalServer, $wgServer;
1016                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1017                 $url = $server . $this->getLocalURL( $query, $variant );
1018                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1019                 return $url;
1020         }
1021
1022         /**
1023          * Get the edit URL for this Title
1024          *
1025          * @return String the URL, or a null string if this is an
1026          *  interwiki link
1027          */
1028         public function getEditURL() {
1029                 if ( $this->mInterwiki != '' ) {
1030                         return '';
1031                 }
1032                 $s = $this->getLocalURL( 'action=edit' );
1033
1034                 return $s;
1035         }
1036
1037         /**
1038          * Get the HTML-escaped displayable text form.
1039          * Used for the title field in <a> tags.
1040          *
1041          * @return String the text, including any prefixes
1042          */
1043         public function getEscapedText() {
1044                 return htmlspecialchars( $this->getPrefixedText() );
1045         }
1046
1047         /**
1048          * Is this Title interwiki?
1049          *
1050          * @return Bool
1051          */
1052         public function isExternal() {
1053                 return ( $this->mInterwiki != '' );
1054         }
1055
1056         /**
1057          * Is this page "semi-protected" - the *only* protection is autoconfirm?
1058          *
1059          * @param $action String Action to check (default: edit)
1060          * @return Bool
1061          */
1062         public function isSemiProtected( $action = 'edit' ) {
1063                 if ( $this->exists() ) {
1064                         $restrictions = $this->getRestrictions( $action );
1065                         if ( count( $restrictions ) > 0 ) {
1066                                 foreach ( $restrictions as $restriction ) {
1067                                         if ( strtolower( $restriction ) != 'autoconfirmed' ) {
1068                                                 return false;
1069                                         }
1070                                 }
1071                         } else {
1072                                 # Not protected
1073                                 return false;
1074                         }
1075                         return true;
1076                 } else {
1077                         # If it doesn't exist, it can't be protected
1078                         return false;
1079                 }
1080         }
1081
1082         /**
1083          * Does the title correspond to a protected article?
1084          *
1085          * @param $action String the action the page is protected from,
1086          * by default checks all actions.
1087          * @return Bool
1088          */
1089         public function isProtected( $action = '' ) {
1090                 global $wgRestrictionLevels;
1091
1092                 $restrictionTypes = $this->getRestrictionTypes();
1093
1094                 # Special pages have inherent protection
1095                 if( $this->getNamespace() == NS_SPECIAL ) {
1096                         return true;
1097                 }
1098
1099                 # Check regular protection levels
1100                 foreach ( $restrictionTypes as $type ) {
1101                         if ( $action == $type || $action == '' ) {
1102                                 $r = $this->getRestrictions( $type );
1103                                 foreach ( $wgRestrictionLevels as $level ) {
1104                                         if ( in_array( $level, $r ) && $level != '' ) {
1105                                                 return true;
1106                                         }
1107                                 }
1108                         }
1109                 }
1110
1111                 return false;
1112         }
1113
1114         /**
1115          * Is this a conversion table for the LanguageConverter?
1116          *
1117          * @return Bool
1118          */
1119         public function isConversionTable() {
1120                 if(
1121                         $this->getNamespace() == NS_MEDIAWIKI &&
1122                         strpos( $this->getText(), 'Conversiontable' ) !== false
1123                 )
1124                 {
1125                         return true;
1126                 }
1127
1128                 return false;
1129         }
1130
1131         /**
1132          * Is $wgUser watching this page?
1133          *
1134          * @return Bool
1135          */
1136         public function userIsWatching() {
1137                 global $wgUser;
1138
1139                 if ( is_null( $this->mWatched ) ) {
1140                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1141                                 $this->mWatched = false;
1142                         } else {
1143                                 $this->mWatched = $wgUser->isWatched( $this );
1144                         }
1145                 }
1146                 return $this->mWatched;
1147         }
1148
1149         /**
1150          * Can $wgUser perform $action on this page?
1151          * This skips potentially expensive cascading permission checks
1152          * as well as avoids expensive error formatting
1153          *
1154          * Suitable for use for nonessential UI controls in common cases, but
1155          * _not_ for functional access control.
1156          *
1157          * May provide false positives, but should never provide a false negative.
1158          *
1159          * @param $action String action that permission needs to be checked for
1160          * @return Bool
1161          */
1162         public function quickUserCan( $action ) {
1163                 return $this->userCan( $action, false );
1164         }
1165
1166         /**
1167          * Determines if $user is unable to edit this page because it has been protected
1168          * by $wgNamespaceProtection.
1169          *
1170          * @param $user User object, $wgUser will be used if not passed
1171          * @return Bool
1172          */
1173         public function isNamespaceProtected( User $user = null ) {
1174                 global $wgNamespaceProtection;
1175
1176                 if ( $user === null ) {
1177                         global $wgUser;
1178                         $user = $wgUser;
1179                 }
1180
1181                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
1182                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
1183                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
1184                                         return true;
1185                                 }
1186                         }
1187                 }
1188                 return false;
1189         }
1190
1191         /**
1192          * Can $wgUser perform $action on this page?
1193          *
1194          * @param $action String action that permission needs to be checked for
1195          * @param $doExpensiveQueries Bool Set this to false to avoid doing unnecessary queries.
1196          * @return Bool
1197          */
1198         public function userCan( $action, $doExpensiveQueries = true ) {
1199                 global $wgUser;
1200                 return ( $this->getUserPermissionsErrorsInternal( $action, $wgUser, $doExpensiveQueries, true ) === array() );
1201         }
1202
1203         /**
1204          * Can $user perform $action on this page?
1205          *
1206          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1207          *
1208          * @param $action String action that permission needs to be checked for
1209          * @param $user User to check
1210          * @param $doExpensiveQueries Bool Set this to false to avoid doing unnecessary queries by
1211          *   skipping checks for cascading protections and user blocks.
1212          * @param $ignoreErrors Array of Strings Set this to a list of message keys whose corresponding errors may be ignored.
1213          * @return Array of arguments to wfMsg to explain permissions problems.
1214          */
1215         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
1216                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1217
1218                 // Remove the errors being ignored.
1219                 foreach ( $errors as $index => $error ) {
1220                         $error_key = is_array( $error ) ? $error[0] : $error;
1221
1222                         if ( in_array( $error_key, $ignoreErrors ) ) {
1223                                 unset( $errors[$index] );
1224                         }
1225                 }
1226
1227                 return $errors;
1228         }
1229
1230         /**
1231          * Permissions checks that fail most often, and which are easiest to test.
1232          *
1233          * @param $action String the action to check
1234          * @param $user User user to check
1235          * @param $errors Array list of current errors
1236          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1237          * @param $short Boolean short circuit on first error
1238          *
1239          * @return Array list of errors
1240          */
1241         private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1242                 if ( $action == 'create' ) {
1243                         if ( ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1244                                  ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) ) ) {
1245                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1246                         }
1247                 } elseif ( $action == 'move' ) {
1248                         if ( !$user->isAllowed( 'move-rootuserpages' )
1249                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1250                                 // Show user page-specific message only if the user can move other pages
1251                                 $errors[] = array( 'cant-move-user-page' );
1252                         }
1253
1254                         // Check if user is allowed to move files if it's a file
1255                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1256                                 $errors[] = array( 'movenotallowedfile' );
1257                         }
1258
1259                         if ( !$user->isAllowed( 'move' ) ) {
1260                                 // User can't move anything
1261                                 global $wgGroupPermissions;
1262                                 $userCanMove = false;
1263                                 if ( isset( $wgGroupPermissions['user']['move'] ) ) {
1264                                         $userCanMove = $wgGroupPermissions['user']['move'];
1265                                 }
1266                                 $autoconfirmedCanMove = false;
1267                                 if ( isset( $wgGroupPermissions['autoconfirmed']['move'] ) ) {
1268                                         $autoconfirmedCanMove = $wgGroupPermissions['autoconfirmed']['move'];
1269                                 }
1270                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1271                                         // custom message if logged-in users without any special rights can move
1272                                         $errors[] = array( 'movenologintext' );
1273                                 } else {
1274                                         $errors[] = array( 'movenotallowed' );
1275                                 }
1276                         }
1277                 } elseif ( $action == 'move-target' ) {
1278                         if ( !$user->isAllowed( 'move' ) ) {
1279                                 // User can't move anything
1280                                 $errors[] = array( 'movenotallowed' );
1281                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1282                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1283                                 // Show user page-specific message only if the user can move other pages
1284                                 $errors[] = array( 'cant-move-to-user-page' );
1285                         }
1286                 } elseif ( !$user->isAllowed( $action ) ) {
1287                         // We avoid expensive display logic for quickUserCan's and such
1288                         $groups = false;
1289                         if ( !$short ) {
1290                                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
1291                                         User::getGroupsWithPermission( $action ) );
1292                         }
1293
1294                         if ( $groups ) {
1295                                 global $wgLang;
1296                                 $return = array(
1297                                         'badaccess-groups',
1298                                         $wgLang->commaList( $groups ),
1299                                         count( $groups )
1300                                 );
1301                         } else {
1302                                 $return = array( 'badaccess-group0' );
1303                         }
1304                         $errors[] = $return;
1305                 }
1306
1307                 return $errors;
1308         }
1309
1310         /**
1311          * Add the resulting error code to the errors array
1312          *
1313          * @param $errors Array list of current errors
1314          * @param $result Mixed result of errors
1315          *
1316          * @return Array list of errors
1317          */
1318         private function resultToError( $errors, $result ) {
1319                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1320                         // A single array representing an error
1321                         $errors[] = $result;
1322                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
1323                         // A nested array representing multiple errors
1324                         $errors = array_merge( $errors, $result );
1325                 } elseif ( $result !== '' && is_string( $result ) ) {
1326                         // A string representing a message-id
1327                         $errors[] = array( $result );
1328                 } elseif ( $result === false ) {
1329                         // a generic "We don't want them to do that"
1330                         $errors[] = array( 'badaccess-group0' );
1331                 }
1332                 return $errors;
1333         }
1334
1335         /**
1336          * Check various permission hooks
1337          *
1338          * @param $action String the action to check
1339          * @param $user User user to check
1340          * @param $errors Array list of current errors
1341          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1342          * @param $short Boolean short circuit on first error
1343          *
1344          * @return Array list of errors
1345          */
1346         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
1347                 // Use getUserPermissionsErrors instead
1348                 $result = '';
1349                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
1350                         return $result ? array() : array( array( 'badaccess-group0' ) );
1351                 }
1352                 // Check getUserPermissionsErrors hook
1353                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
1354                         $errors = $this->resultToError( $errors, $result );
1355                 }
1356                 // Check getUserPermissionsErrorsExpensive hook
1357                 if ( $doExpensiveQueries && !( $short && count( $errors ) > 0 ) &&
1358                          !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) ) ) {
1359                         $errors = $this->resultToError( $errors, $result );
1360                 }
1361
1362                 return $errors;
1363         }
1364
1365         /**
1366          * Check permissions on special pages & namespaces
1367          *
1368          * @param $action String the action to check
1369          * @param $user User user to check
1370          * @param $errors Array list of current errors
1371          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1372          * @param $short Boolean short circuit on first error
1373          *
1374          * @return Array list of errors
1375          */
1376         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1377                 # Only 'createaccount' and 'execute' can be performed on
1378                 # special pages, which don't actually exist in the DB.
1379                 $specialOKActions = array( 'createaccount', 'execute' );
1380                 if ( NS_SPECIAL == $this->mNamespace && !in_array( $action, $specialOKActions ) ) {
1381                         $errors[] = array( 'ns-specialprotected' );
1382                 }
1383
1384                 # Check $wgNamespaceProtection for restricted namespaces
1385                 if ( $this->isNamespaceProtected( $user ) ) {
1386                         $ns = $this->mNamespace == NS_MAIN ?
1387                                 wfMsg( 'nstab-main' ) : $this->getNsText();
1388                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
1389                                 array( 'protectedinterface' ) : array( 'namespaceprotected',  $ns );
1390                 }
1391
1392                 return $errors;
1393         }
1394
1395         /**
1396          * Check CSS/JS sub-page permissions
1397          *
1398          * @param $action String the action to check
1399          * @param $user User user to check
1400          * @param $errors Array list of current errors
1401          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1402          * @param $short Boolean short circuit on first error
1403          *
1404          * @return Array list of errors
1405          */
1406         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1407                 # Protect css/js subpages of user pages
1408                 # XXX: this might be better using restrictions
1409                 # XXX: Find a way to work around the php bug that prevents using $this->userCanEditCssSubpage()
1410                 #      and $this->userCanEditJsSubpage() from working
1411                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
1412                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' )
1413                                 && !preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
1414                         if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
1415                                 $errors[] = array( 'customcssprotected' );
1416                         } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
1417                                 $errors[] = array( 'customjsprotected' );
1418                         }
1419                 }
1420
1421                 return $errors;
1422         }
1423
1424         /**
1425          * Check against page_restrictions table requirements on this
1426          * page. The user must possess all required rights for this
1427          * action.
1428          *
1429          * @param $action String the action to check
1430          * @param $user User user to check
1431          * @param $errors Array list of current errors
1432          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1433          * @param $short Boolean short circuit on first error
1434          *
1435          * @return Array list of errors
1436          */
1437         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1438                 foreach ( $this->getRestrictions( $action ) as $right ) {
1439                         // Backwards compatibility, rewrite sysop -> protect
1440                         if ( $right == 'sysop' ) {
1441                                 $right = 'protect';
1442                         }
1443                         if ( $right != '' && !$user->isAllowed( $right ) ) {
1444                                 // Users with 'editprotected' permission can edit protected pages
1445                                 if ( $action == 'edit' && $user->isAllowed( 'editprotected' ) ) {
1446                                         // Users with 'editprotected' permission cannot edit protected pages
1447                                         // with cascading option turned on.
1448                                         if ( $this->mCascadeRestriction ) {
1449                                                 $errors[] = array( 'protectedpagetext', $right );
1450                                         }
1451                                 } else {
1452                                         $errors[] = array( 'protectedpagetext', $right );
1453                                 }
1454                         }
1455                 }
1456
1457                 return $errors;
1458         }
1459
1460         /**
1461          * Check restrictions on cascading pages.
1462          *
1463          * @param $action String the action to check
1464          * @param $user User to check
1465          * @param $errors Array list of current errors
1466          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1467          * @param $short Boolean short circuit on first error
1468          *
1469          * @return Array list of errors
1470          */
1471         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1472                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
1473                         # We /could/ use the protection level on the source page, but it's
1474                         # fairly ugly as we have to establish a precedence hierarchy for pages
1475                         # included by multiple cascade-protected pages. So just restrict
1476                         # it to people with 'protect' permission, as they could remove the
1477                         # protection anyway.
1478                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
1479                         # Cascading protection depends on more than this page...
1480                         # Several cascading protected pages may include this page...
1481                         # Check each cascading level
1482                         # This is only for protection restrictions, not for all actions
1483                         if ( isset( $restrictions[$action] ) ) {
1484                                 foreach ( $restrictions[$action] as $right ) {
1485                                         $right = ( $right == 'sysop' ) ? 'protect' : $right;
1486                                         if ( $right != '' && !$user->isAllowed( $right ) ) {
1487                                                 $pages = '';
1488                                                 foreach ( $cascadingSources as $page )
1489                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
1490                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
1491                                         }
1492                                 }
1493                         }
1494                 }
1495
1496                 return $errors;
1497         }
1498
1499         /**
1500          * Check action permissions not already checked in checkQuickPermissions
1501          *
1502          * @param $action String the action to check
1503          * @param $user User to check
1504          * @param $errors Array list of current errors
1505          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1506          * @param $short Boolean short circuit on first error
1507          *
1508          * @return Array list of errors
1509          */
1510         private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1511                 if ( $action == 'protect' ) {
1512                         if ( $this->getUserPermissionsErrors( 'edit', $user ) != array() ) {
1513                                 // If they can't edit, they shouldn't protect.
1514                                 $errors[] = array( 'protect-cantedit' );
1515                         }
1516                 } elseif ( $action == 'create' ) {
1517                         $title_protection = $this->getTitleProtection();
1518                         if( $title_protection ) {
1519                                 if( $title_protection['pt_create_perm'] == 'sysop' ) {
1520                                         $title_protection['pt_create_perm'] = 'protect'; // B/C
1521                                 }
1522                                 if( $title_protection['pt_create_perm'] == '' || !$user->isAllowed( $title_protection['pt_create_perm'] ) ) {
1523                                         $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
1524                                 }
1525                         }
1526                 } elseif ( $action == 'move' ) {
1527                         // Check for immobile pages
1528                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
1529                                 // Specific message for this case
1530                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
1531                         } elseif ( !$this->isMovable() ) {
1532                                 // Less specific message for rarer cases
1533                                 $errors[] = array( 'immobile-page' );
1534                         }
1535                 } elseif ( $action == 'move-target' ) {
1536                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
1537                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
1538                         } elseif ( !$this->isMovable() ) {
1539                                 $errors[] = array( 'immobile-target-page' );
1540                         }
1541                 }
1542                 return $errors;
1543         }
1544
1545         /**
1546          * Check that the user isn't blocked from editting.
1547          *
1548          * @param $action String the action to check
1549          * @param $user User to check
1550          * @param $errors Array list of current errors
1551          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1552          * @param $short Boolean short circuit on first error
1553          *
1554          * @return Array list of errors
1555          */
1556         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
1557                 if( !$doExpensiveQueries ) {
1558                         return $errors;
1559                 }
1560
1561                 global $wgContLang, $wgLang, $wgEmailConfirmToEdit;
1562
1563                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() && $action != 'createaccount' ) {
1564                         $errors[] = array( 'confirmedittext' );
1565                 }
1566
1567                 if ( in_array( $action, array( 'read', 'createaccount', 'unblock' ) ) ){
1568                         // Edit blocks should not affect reading.
1569                         // Account creation blocks handled at userlogin.
1570                         // Unblocking handled in SpecialUnblock
1571                 } elseif( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ){
1572                         // Don't block the user from editing their own talk page unless they've been
1573                         // explicitly blocked from that too.
1574                 } elseif( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
1575                         $block = $user->mBlock;
1576
1577                         // This is from OutputPage::blockedPage
1578                         // Copied at r23888 by werdna
1579
1580                         $id = $user->blockedBy();
1581                         $reason = $user->blockedFor();
1582                         if ( $reason == '' ) {
1583                                 $reason = wfMsg( 'blockednoreason' );
1584                         }
1585                         $ip = wfGetIP();
1586
1587                         if ( is_numeric( $id ) ) {
1588                                 $name = User::whoIs( $id );
1589                         } else {
1590                                 $name = $id;
1591                         }
1592
1593                         $link = '[[' . $wgContLang->getNsText( NS_USER ) . ":{$name}|{$name}]]";
1594                         $blockid = $block->getId();
1595                         $blockExpiry = $user->mBlock->mExpiry;
1596                         $blockTimestamp = $wgLang->timeanddate( wfTimestamp( TS_MW, $user->mBlock->mTimestamp ), true );
1597                         if ( $blockExpiry == 'infinity' ) {
1598                                 $blockExpiry = wfMessage( 'infiniteblock' )->text();
1599                         } else {
1600                                 $blockExpiry = $wgLang->timeanddate( wfTimestamp( TS_MW, $blockExpiry ), true );
1601                         }
1602
1603                         $intended = strval( $user->mBlock->getTarget() );
1604
1605                         $errors[] = array( ( $block->mAuto ? 'autoblockedtext' : 'blockedtext' ), $link, $reason, $ip, $name,
1606                                 $blockid, $blockExpiry, $intended, $blockTimestamp );
1607                 }
1608
1609                 return $errors;
1610         }
1611
1612         /**
1613          * Can $user perform $action on this page? This is an internal function,
1614          * which checks ONLY that previously checked by userCan (i.e. it leaves out
1615          * checks on wfReadOnly() and blocks)
1616          *
1617          * @param $action String action that permission needs to be checked for
1618          * @param $user User to check
1619          * @param $doExpensiveQueries Bool Set this to false to avoid doing unnecessary queries.
1620          * @param $short Bool Set this to true to stop after the first permission error.
1621          * @return Array of arrays of the arguments to wfMsg to explain permissions problems.
1622          */
1623         protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
1624                 wfProfileIn( __METHOD__ );
1625
1626                 $errors = array();
1627                 $checks = array(
1628                         'checkQuickPermissions',
1629                         'checkPermissionHooks',
1630                         'checkSpecialsAndNSPermissions',
1631                         'checkCSSandJSPermissions',
1632                         'checkPageRestrictions',
1633                         'checkCascadingSourcesRestrictions',
1634                         'checkActionPermissions',
1635                         'checkUserBlock'
1636                 );
1637
1638                 while( count( $checks ) > 0 &&
1639                            !( $short && count( $errors ) > 0 ) ) {
1640                         $method = array_shift( $checks );
1641                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
1642                 }
1643
1644                 wfProfileOut( __METHOD__ );
1645                 return $errors;
1646         }
1647
1648         /**
1649          * Is this title subject to title protection?
1650          * Title protection is the one applied against creation of such title.
1651          *
1652          * @return Mixed An associative array representing any existent title
1653          *   protection, or false if there's none.
1654          */
1655         private function getTitleProtection() {
1656                 // Can't protect pages in special namespaces
1657                 if ( $this->getNamespace() < 0 ) {
1658                         return false;
1659                 }
1660
1661                 // Can't protect pages that exist.
1662                 if ( $this->exists() ) {
1663                         return false;
1664                 }
1665
1666                 if ( !isset( $this->mTitleProtection ) ) {
1667                         $dbr = wfGetDB( DB_SLAVE );
1668                         $res = $dbr->select( 'protected_titles', '*',
1669                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
1670                                 __METHOD__ );
1671
1672                         // fetchRow returns false if there are no rows.
1673                         $this->mTitleProtection = $dbr->fetchRow( $res );
1674                 }
1675                 return $this->mTitleProtection;
1676         }
1677
1678         /**
1679          * Update the title protection status
1680          *
1681          * @param $create_perm String Permission required for creation
1682          * @param $reason String Reason for protection
1683          * @param $expiry String Expiry timestamp
1684          * @return boolean true
1685          */
1686         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
1687                 global $wgUser, $wgContLang;
1688
1689                 if ( $create_perm == implode( ',', $this->getRestrictions( 'create' ) )
1690                         && $expiry == $this->mRestrictionsExpiry['create'] ) {
1691                         // No change
1692                         return true;
1693                 }
1694
1695                 list ( $namespace, $title ) = array( $this->getNamespace(), $this->getDBkey() );
1696
1697                 $dbw = wfGetDB( DB_MASTER );
1698
1699                 $encodedExpiry = $dbw->encodeExpiry( $expiry );
1700
1701                 $expiry_description = '';
1702                 if ( $encodedExpiry != $dbw->getInfinity() ) {
1703                         $expiry_description = ' (' . wfMsgForContent( 'protect-expiring', $wgContLang->timeanddate( $expiry ),
1704                                 $wgContLang->date( $expiry ) , $wgContLang->time( $expiry ) ) . ')';
1705                 } else {
1706                         $expiry_description .= ' (' . wfMsgForContent( 'protect-expiry-indefinite' ) . ')';
1707                 }
1708
1709                 # Update protection table
1710                 if ( $create_perm != '' ) {
1711                         $this->mTitleProtection = array(
1712                                         'pt_namespace' => $namespace,
1713                                         'pt_title' => $title,
1714                                         'pt_create_perm' => $create_perm,
1715                                         'pt_timestamp' => $dbw->encodeExpiry( wfTimestampNow() ),
1716                                         'pt_expiry' => $encodedExpiry,
1717                                         'pt_user' => $wgUser->getId(),
1718                                         'pt_reason' => $reason,
1719                                 );
1720                         $dbw->replace( 'protected_titles', array( array( 'pt_namespace', 'pt_title' ) ),
1721                                 $this->mTitleProtection, __METHOD__     );
1722                 } else {
1723                         $dbw->delete( 'protected_titles', array( 'pt_namespace' => $namespace,
1724                                 'pt_title' => $title ), __METHOD__ );
1725                         $this->mTitleProtection = false;
1726                 }
1727
1728                 # Update the protection log
1729                 if ( $dbw->affectedRows() ) {
1730                         $log = new LogPage( 'protect' );
1731
1732                         if ( $create_perm ) {
1733                                 $params = array( "[create=$create_perm] $expiry_description", '' );
1734                                 $log->addEntry( ( isset( $this->mRestrictions['create'] ) && $this->mRestrictions['create'] ) ? 'modify' : 'protect', $this, trim( $reason ), $params );
1735                         } else {
1736                                 $log->addEntry( 'unprotect', $this, $reason );
1737                         }
1738                 }
1739
1740                 return true;
1741         }
1742
1743         /**
1744          * Remove any title protection due to page existing
1745          */
1746         public function deleteTitleProtection() {
1747                 $dbw = wfGetDB( DB_MASTER );
1748
1749                 $dbw->delete(
1750                         'protected_titles',
1751                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
1752                         __METHOD__
1753                 );
1754                 $this->mTitleProtection = false;
1755         }
1756
1757         /**
1758          * Would anybody with sufficient privileges be able to move this page?
1759          * Some pages just aren't movable.
1760          *
1761          * @return Bool TRUE or FALSE
1762          */
1763         public function isMovable() {
1764                 return MWNamespace::isMovable( $this->getNamespace() ) && $this->getInterwiki() == '';
1765         }
1766
1767         /**
1768          * Can $wgUser read this page?
1769          *
1770          * @return Bool
1771          * @todo fold these checks into userCan()
1772          */
1773         public function userCanRead() {
1774                 global $wgUser, $wgGroupPermissions;
1775
1776                 static $useShortcut = null;
1777
1778                 # Initialize the $useShortcut boolean, to determine if we can skip quite a bit of code below
1779                 if ( is_null( $useShortcut ) ) {
1780                         global $wgRevokePermissions;
1781                         $useShortcut = true;
1782                         if ( empty( $wgGroupPermissions['*']['read'] ) ) {
1783                                 # Not a public wiki, so no shortcut
1784                                 $useShortcut = false;
1785                         } elseif ( !empty( $wgRevokePermissions ) ) {
1786                                 /**
1787                                  * Iterate through each group with permissions being revoked (key not included since we don't care
1788                                  * what the group name is), then check if the read permission is being revoked. If it is, then
1789                                  * we don't use the shortcut below since the user might not be able to read, even though anon
1790                                  * reading is allowed.
1791                                  */
1792                                 foreach ( $wgRevokePermissions as $perms ) {
1793                                         if ( !empty( $perms['read'] ) ) {
1794                                                 # We might be removing the read right from the user, so no shortcut
1795                                                 $useShortcut = false;
1796                                                 break;
1797                                         }
1798                                 }
1799                         }
1800                 }
1801
1802                 $result = null;
1803                 wfRunHooks( 'userCan', array( &$this, &$wgUser, 'read', &$result ) );
1804                 if ( $result !== null ) {
1805                         return $result;
1806                 }
1807
1808                 # Shortcut for public wikis, allows skipping quite a bit of code
1809                 if ( $useShortcut ) {
1810                         return true;
1811                 }
1812
1813                 if ( $wgUser->isAllowed( 'read' ) ) {
1814                         return true;
1815                 } else {
1816                         global $wgWhitelistRead;
1817
1818                         # Always grant access to the login page.
1819                         # Even anons need to be able to log in.
1820                         if ( $this->isSpecial( 'Userlogin' ) || $this->isSpecial( 'ChangePassword' ) ) {
1821                                 return true;
1822                         }
1823
1824                         # Bail out if there isn't whitelist
1825                         if ( !is_array( $wgWhitelistRead ) ) {
1826                                 return false;
1827                         }
1828
1829                         # Check for explicit whitelisting
1830                         $name = $this->getPrefixedText();
1831                         $dbName = $this->getPrefixedDBKey();
1832                         // Check with and without underscores
1833                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) )
1834                                 return true;
1835
1836                         # Old settings might have the title prefixed with
1837                         # a colon for main-namespace pages
1838                         if ( $this->getNamespace() == NS_MAIN ) {
1839                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
1840                                         return true;
1841                                 }
1842                         }
1843
1844                         # If it's a special page, ditch the subpage bit and check again
1845                         if ( $this->getNamespace() == NS_SPECIAL ) {
1846                                 $name = $this->getDBkey();
1847                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
1848                                 if ( $name === false ) {
1849                                         # Invalid special page, but we show standard login required message
1850                                         return false;
1851                                 }
1852
1853                                 $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
1854                                 if ( in_array( $pure, $wgWhitelistRead, true ) ) {
1855                                         return true;
1856                                 }
1857                         }
1858
1859                 }
1860                 return false;
1861         }
1862
1863         /**
1864          * Is this the mainpage?
1865          * @note Title::newFromText seams to be sufficiently optimized by the title
1866          * cache that we don't need to over-optimize by doing direct comparisons and
1867          * acidentally creating new bugs where $title->equals( Title::newFromText() )
1868          * ends up reporting something differently than $title->isMainPage();
1869          *
1870          * @return Bool
1871          */
1872         public function isMainPage() {
1873                 return $this->equals( Title::newMainPage() );
1874         }
1875
1876         /**
1877          * Is this a talk page of some sort?
1878          *
1879          * @return Bool
1880          */
1881         public function isTalkPage() {
1882                 return MWNamespace::isTalk( $this->getNamespace() );
1883         }
1884
1885         /**
1886          * Is this a subpage?
1887          *
1888          * @return Bool
1889          */
1890         public function isSubpage() {
1891                 return MWNamespace::hasSubpages( $this->mNamespace )
1892                         ? strpos( $this->getText(), '/' ) !== false
1893                         : false;
1894         }
1895
1896         /**
1897          * Does this have subpages?  (Warning, usually requires an extra DB query.)
1898          *
1899          * @return Bool
1900          */
1901         public function hasSubpages() {
1902                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1903                         # Duh
1904                         return false;
1905                 }
1906
1907                 # We dynamically add a member variable for the purpose of this method
1908                 # alone to cache the result.  There's no point in having it hanging
1909                 # around uninitialized in every Title object; therefore we only add it
1910                 # if needed and don't declare it statically.
1911                 if ( isset( $this->mHasSubpages ) ) {
1912                         return $this->mHasSubpages;
1913                 }
1914
1915                 $subpages = $this->getSubpages( 1 );
1916                 if ( $subpages instanceof TitleArray ) {
1917                         return $this->mHasSubpages = (bool)$subpages->count();
1918                 }
1919                 return $this->mHasSubpages = false;
1920         }
1921
1922         /**
1923          * Get all subpages of this page.
1924          *
1925          * @param $limit Int maximum number of subpages to fetch; -1 for no limit
1926          * @return mixed TitleArray, or empty array if this page's namespace
1927          *  doesn't allow subpages
1928          */
1929         public function getSubpages( $limit = -1 ) {
1930                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
1931                         return array();
1932                 }
1933
1934                 $dbr = wfGetDB( DB_SLAVE );
1935                 $conds['page_namespace'] = $this->getNamespace();
1936                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
1937                 $options = array();
1938                 if ( $limit > -1 ) {
1939                         $options['LIMIT'] = $limit;
1940                 }
1941                 return $this->mSubpages = TitleArray::newFromResult(
1942                         $dbr->select( 'page',
1943                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
1944                                 $conds,
1945                                 __METHOD__,
1946                                 $options
1947                         )
1948                 );
1949         }
1950
1951         /**
1952          * Could this page contain custom CSS or JavaScript, based
1953          * on the title?
1954          *
1955          * @return Bool
1956          */
1957         public function isCssOrJsPage() {
1958                 return $this->mNamespace == NS_MEDIAWIKI
1959                         && preg_match( '!\.(?:css|js)$!u', $this->mTextform ) > 0;
1960         }
1961
1962         /**
1963          * Is this a .css or .js subpage of a user page?
1964          * @return Bool
1965          */
1966         public function isCssJsSubpage() {
1967                 return ( NS_USER == $this->mNamespace and preg_match( "/\\/.*\\.(?:css|js)$/", $this->mTextform ) );
1968         }
1969
1970         /**
1971          * Is this a *valid* .css or .js subpage of a user page?
1972          *
1973          * @return Bool
1974          * @deprecated since 1.17
1975          */
1976         public function isValidCssJsSubpage() {
1977                 return $this->isCssJsSubpage();
1978         }
1979
1980         /**
1981          * Trim down a .css or .js subpage title to get the corresponding skin name
1982          *
1983          * @return string containing skin name from .css or .js subpage title
1984          */
1985         public function getSkinFromCssJsSubpage() {
1986                 $subpage = explode( '/', $this->mTextform );
1987                 $subpage = $subpage[ count( $subpage ) - 1 ];
1988                 return( str_replace( array( '.css', '.js' ), array( '', '' ), $subpage ) );
1989         }
1990
1991         /**
1992          * Is this a .css subpage of a user page?
1993          *
1994          * @return Bool
1995          */
1996         public function isCssSubpage() {
1997                 return ( NS_USER == $this->mNamespace && preg_match( "/\\/.*\\.css$/", $this->mTextform ) );
1998         }
1999
2000         /**
2001          * Is this a .js subpage of a user page?
2002          *
2003          * @return Bool
2004          */
2005         public function isJsSubpage() {
2006                 return ( NS_USER == $this->mNamespace && preg_match( "/\\/.*\\.js$/", $this->mTextform ) );
2007         }
2008
2009         /**
2010          * Protect css subpages of user pages: can $wgUser edit
2011          * this page?
2012          *
2013          * @return Bool
2014          * @todo XXX: this might be better using restrictions
2015          */
2016         public function userCanEditCssSubpage() {
2017                 global $wgUser;
2018                 return ( ( $wgUser->isAllowedAll( 'editusercssjs', 'editusercss' ) )
2019                         || preg_match( '/^' . preg_quote( $wgUser->getName(), '/' ) . '\//', $this->mTextform ) );
2020         }
2021
2022         /**
2023          * Protect js subpages of user pages: can $wgUser edit
2024          * this page?
2025          *
2026          * @return Bool
2027          * @todo XXX: this might be better using restrictions
2028          */
2029         public function userCanEditJsSubpage() {
2030                 global $wgUser;
2031                 return ( ( $wgUser->isAllowedAll( 'editusercssjs', 'edituserjs' ) )
2032                            || preg_match( '/^' . preg_quote( $wgUser->getName(), '/' ) . '\//', $this->mTextform ) );
2033         }
2034
2035         /**
2036          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2037          *
2038          * @return Bool If the page is subject to cascading restrictions.
2039          */
2040         public function isCascadeProtected() {
2041                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2042                 return ( $sources > 0 );
2043         }
2044
2045         /**
2046          * Cascading protection: Get the source of any cascading restrictions on this page.
2047          *
2048          * @param $getPages Bool Whether or not to retrieve the actual pages
2049          *        that the restrictions have come from.
2050          * @return Mixed Array of Title objects of the pages from which cascading restrictions
2051          *     have come, false for none, or true if such restrictions exist, but $getPages
2052          *     was not set.  The restriction array is an array of each type, each of which
2053          *     contains a array of unique groups.
2054          */
2055         public function getCascadeProtectionSources( $getPages = true ) {
2056                 global $wgContLang;
2057                 $pagerestrictions = array();
2058
2059                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2060                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2061                 } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2062                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2063                 }
2064
2065                 wfProfileIn( __METHOD__ );
2066
2067                 $dbr = wfGetDB( DB_SLAVE );
2068
2069                 if ( $this->getNamespace() == NS_FILE ) {
2070                         $tables = array( 'imagelinks', 'page_restrictions' );
2071                         $where_clauses = array(
2072                                 'il_to' => $this->getDBkey(),
2073                                 'il_from=pr_page',
2074                                 'pr_cascade' => 1
2075                         );
2076                 } else {
2077                         $tables = array( 'templatelinks', 'page_restrictions' );
2078                         $where_clauses = array(
2079                                 'tl_namespace' => $this->getNamespace(),
2080                                 'tl_title' => $this->getDBkey(),
2081                                 'tl_from=pr_page',
2082                                 'pr_cascade' => 1
2083                         );
2084                 }
2085
2086                 if ( $getPages ) {
2087                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2088                                                    'pr_expiry', 'pr_type', 'pr_level' );
2089                         $where_clauses[] = 'page_id=pr_page';
2090                         $tables[] = 'page';
2091                 } else {
2092                         $cols = array( 'pr_expiry' );
2093                 }
2094
2095                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2096
2097                 $sources = $getPages ? array() : false;
2098                 $now = wfTimestampNow();
2099                 $purgeExpired = false;
2100
2101                 foreach ( $res as $row ) {
2102                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2103                         if ( $expiry > $now ) {
2104                                 if ( $getPages ) {
2105                                         $page_id = $row->pr_page;
2106                                         $page_ns = $row->page_namespace;
2107                                         $page_title = $row->page_title;
2108                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2109                                         # Add groups needed for each restriction type if its not already there
2110                                         # Make sure this restriction type still exists
2111
2112                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2113                                                 $pagerestrictions[$row->pr_type] = array();
2114                                         }
2115
2116                                         if ( isset( $pagerestrictions[$row->pr_type] ) &&
2117                                                  !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] ) ) {
2118                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2119                                         }
2120                                 } else {
2121                                         $sources = true;
2122                                 }
2123                         } else {
2124                                 // Trigger lazy purge of expired restrictions from the db
2125                                 $purgeExpired = true;
2126                         }
2127                 }
2128                 if ( $purgeExpired ) {
2129                         Title::purgeExpiredRestrictions();
2130                 }
2131
2132                 if ( $getPages ) {
2133                         $this->mCascadeSources = $sources;
2134                         $this->mCascadingRestrictions = $pagerestrictions;
2135                 } else {
2136                         $this->mHasCascadingRestrictions = $sources;
2137                 }
2138
2139                 wfProfileOut( __METHOD__ );
2140                 return array( $sources, $pagerestrictions );
2141         }
2142
2143         /**
2144          * Returns cascading restrictions for the current article
2145          *
2146          * @return Boolean
2147          */
2148         function areRestrictionsCascading() {
2149                 if ( !$this->mRestrictionsLoaded ) {
2150                         $this->loadRestrictions();
2151                 }
2152
2153                 return $this->mCascadeRestriction;
2154         }
2155
2156         /**
2157          * Loads a string into mRestrictions array
2158          *
2159          * @param $res Resource restrictions as an SQL result.
2160          * @param $oldFashionedRestrictions String comma-separated list of page
2161          *        restrictions from page table (pre 1.10)
2162          */
2163         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2164                 $rows = array();
2165
2166                 foreach ( $res as $row ) {
2167                         $rows[] = $row;
2168                 }
2169
2170                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2171         }
2172
2173         /**
2174          * Compiles list of active page restrictions from both page table (pre 1.10)
2175          * and page_restrictions table for this existing page.
2176          * Public for usage by LiquidThreads.
2177          *
2178          * @param $rows array of db result objects
2179          * @param $oldFashionedRestrictions string comma-separated list of page
2180          *        restrictions from page table (pre 1.10)
2181          */
2182         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2183                 global $wgContLang;
2184                 $dbr = wfGetDB( DB_SLAVE );
2185
2186                 $restrictionTypes = $this->getRestrictionTypes();
2187
2188                 foreach ( $restrictionTypes as $type ) {
2189                         $this->mRestrictions[$type] = array();
2190                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2191                 }
2192
2193                 $this->mCascadeRestriction = false;
2194
2195                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2196
2197                 if ( $oldFashionedRestrictions === null ) {
2198                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2199                                 array( 'page_id' => $this->getArticleId() ), __METHOD__ );
2200                 }
2201
2202                 if ( $oldFashionedRestrictions != '' ) {
2203
2204                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2205                                 $temp = explode( '=', trim( $restrict ) );
2206                                 if ( count( $temp ) == 1 ) {
2207                                         // old old format should be treated as edit/move restriction
2208                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2209                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2210                                 } else {
2211                                         $this->mRestrictions[$temp[0]] = explode( ',', trim( $temp[1] ) );
2212                                 }
2213                         }
2214
2215                         $this->mOldRestrictions = true;
2216
2217                 }
2218
2219                 if ( count( $rows ) ) {
2220                         # Current system - load second to make them override.
2221                         $now = wfTimestampNow();
2222                         $purgeExpired = false;
2223
2224                         # Cycle through all the restrictions.
2225                         foreach ( $rows as $row ) {
2226
2227                                 // Don't take care of restrictions types that aren't allowed
2228                                 if ( !in_array( $row->pr_type, $restrictionTypes ) )
2229                                         continue;
2230
2231                                 // This code should be refactored, now that it's being used more generally,
2232                                 // But I don't really see any harm in leaving it in Block for now -werdna
2233                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2234
2235                                 // Only apply the restrictions if they haven't expired!
2236                                 if ( !$expiry || $expiry > $now ) {
2237                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2238                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2239
2240                                         $this->mCascadeRestriction |= $row->pr_cascade;
2241                                 } else {
2242                                         // Trigger a lazy purge of expired restrictions
2243                                         $purgeExpired = true;
2244                                 }
2245                         }
2246
2247                         if ( $purgeExpired ) {
2248                                 Title::purgeExpiredRestrictions();
2249                         }
2250                 }
2251
2252                 $this->mRestrictionsLoaded = true;
2253         }
2254
2255         /**
2256          * Load restrictions from the page_restrictions table
2257          *
2258          * @param $oldFashionedRestrictions String comma-separated list of page
2259          *        restrictions from page table (pre 1.10)
2260          */
2261         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2262                 global $wgContLang;
2263                 if ( !$this->mRestrictionsLoaded ) {
2264                         if ( $this->exists() ) {
2265                                 $dbr = wfGetDB( DB_SLAVE );
2266
2267                                 $res = $dbr->select(
2268                                         'page_restrictions',
2269                                         '*',
2270                                         array( 'pr_page' => $this->getArticleId() ),
2271                                         __METHOD__
2272                                 );
2273
2274                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2275                         } else {
2276                                 $title_protection = $this->getTitleProtection();
2277
2278                                 if ( $title_protection ) {
2279                                         $now = wfTimestampNow();
2280                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2281
2282                                         if ( !$expiry || $expiry > $now ) {
2283                                                 // Apply the restrictions
2284                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2285                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2286                                         } else { // Get rid of the old restrictions
2287                                                 Title::purgeExpiredRestrictions();
2288                                                 $this->mTitleProtection = false;
2289                                         }
2290                                 } else {
2291                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2292                                 }
2293                                 $this->mRestrictionsLoaded = true;
2294                         }
2295                 }
2296         }
2297
2298         /**
2299          * Purge expired restrictions from the page_restrictions table
2300          */
2301         static function purgeExpiredRestrictions() {
2302                 $dbw = wfGetDB( DB_MASTER );
2303                 $dbw->delete(
2304                         'page_restrictions',
2305                         array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2306                         __METHOD__
2307                 );
2308
2309                 $dbw->delete(
2310                         'protected_titles',
2311                         array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2312                         __METHOD__
2313                 );
2314         }
2315
2316         /**
2317          * Accessor/initialisation for mRestrictions
2318          *
2319          * @param $action String action that permission needs to be checked for
2320          * @return Array of Strings the array of groups allowed to edit this article
2321          */
2322         public function getRestrictions( $action ) {
2323                 if ( !$this->mRestrictionsLoaded ) {
2324                         $this->loadRestrictions();
2325                 }
2326                 return isset( $this->mRestrictions[$action] )
2327                                 ? $this->mRestrictions[$action]
2328                                 : array();
2329         }
2330
2331         /**
2332          * Get the expiry time for the restriction against a given action
2333          *
2334          * @return String|Bool 14-char timestamp, or 'infinity' if the page is protected forever
2335          *      or not protected at all, or false if the action is not recognised.
2336          */
2337         public function getRestrictionExpiry( $action ) {
2338                 if ( !$this->mRestrictionsLoaded ) {
2339                         $this->loadRestrictions();
2340                 }
2341                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2342         }
2343
2344         /**
2345          * Is there a version of this page in the deletion archive?
2346          *
2347          * @param $includeSuppressed Boolean Include suppressed revisions?
2348          * @return Int the number of archived revisions
2349          */
2350         public function isDeleted( $includeSuppressed = false ) {
2351                 if ( $this->getNamespace() < 0 ) {
2352                         $n = 0;
2353                 } else {
2354                         $dbr = wfGetDB( DB_SLAVE );
2355                         $conditions = array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() );
2356
2357                         if( !$includeSuppressed ) {
2358                                 $suppressedTextBits = REVISION::DELETED_TEXT | REVISION::DELETED_RESTRICTED;
2359                                 $conditions[] = $dbr->bitAnd('ar_deleted', $suppressedTextBits ) .
2360                                 ' != ' . $suppressedTextBits;
2361                         }
2362
2363                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
2364                                 $conditions,
2365                                 __METHOD__
2366                         );
2367                         if ( $this->getNamespace() == NS_FILE ) {
2368                                 $fconditions = array( 'fa_name' => $this->getDBkey() );
2369                                 if( !$includeSuppressed ) {
2370                                         $suppressedTextBits = FILE::DELETED_FILE | FILE::DELETED_RESTRICTED;
2371                                         $fconditions[] = $dbr->bitAnd('fa_deleted', $suppressedTextBits ) .
2372                                         ' != ' . $suppressedTextBits;
2373                                 }
2374
2375                                 $n += $dbr->selectField( 'filearchive',
2376                                         'COUNT(*)',
2377                                         $fconditions,
2378                                         __METHOD__
2379                                 );
2380                         }
2381                 }
2382                 return (int)$n;
2383         }
2384
2385         /**
2386          * Is there a version of this page in the deletion archive?
2387          *
2388          * @return Boolean
2389          */
2390         public function isDeletedQuick() {
2391                 if ( $this->getNamespace() < 0 ) {
2392                         return false;
2393                 }
2394                 $dbr = wfGetDB( DB_SLAVE );
2395                 $deleted = (bool)$dbr->selectField( 'archive', '1',
2396                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2397                         __METHOD__
2398                 );
2399                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
2400                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
2401                                 array( 'fa_name' => $this->getDBkey() ),
2402                                 __METHOD__
2403                         );
2404                 }
2405                 return $deleted;
2406         }
2407
2408         /**
2409          * Get the article ID for this Title from the link cache,
2410          * adding it if necessary
2411          *
2412          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select
2413          *  for update
2414          * @return Int the ID
2415          */
2416         public function getArticleID( $flags = 0 ) {
2417                 if ( $this->getNamespace() < 0 ) {
2418                         return $this->mArticleID = 0;
2419                 }
2420                 $linkCache = LinkCache::singleton();
2421                 if ( $flags & self::GAID_FOR_UPDATE ) {
2422                         $oldUpdate = $linkCache->forUpdate( true );
2423                         $linkCache->clearLink( $this );
2424                         $this->mArticleID = $linkCache->addLinkObj( $this );
2425                         $linkCache->forUpdate( $oldUpdate );
2426                 } else {
2427                         if ( -1 == $this->mArticleID ) {
2428                                 $this->mArticleID = $linkCache->addLinkObj( $this );
2429                         }
2430                 }
2431                 return $this->mArticleID;
2432         }
2433
2434         /**
2435          * Is this an article that is a redirect page?
2436          * Uses link cache, adding it if necessary
2437          *
2438          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select for update
2439          * @return Bool
2440          */
2441         public function isRedirect( $flags = 0 ) {
2442                 if ( !is_null( $this->mRedirect ) ) {
2443                         return $this->mRedirect;
2444                 }
2445                 # Calling getArticleID() loads the field from cache as needed
2446                 if ( !$this->getArticleID( $flags ) ) {
2447                         return $this->mRedirect = false;
2448                 }
2449                 $linkCache = LinkCache::singleton();
2450                 $this->mRedirect = (bool)$linkCache->getGoodLinkFieldObj( $this, 'redirect' );
2451
2452                 return $this->mRedirect;
2453         }
2454
2455         /**
2456          * What is the length of this page?
2457          * Uses link cache, adding it if necessary
2458          *
2459          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select for update
2460          * @return Int
2461          */
2462         public function getLength( $flags = 0 ) {
2463                 if ( $this->mLength != -1 ) {
2464                         return $this->mLength;
2465                 }
2466                 # Calling getArticleID() loads the field from cache as needed
2467                 if ( !$this->getArticleID( $flags ) ) {
2468                         return $this->mLength = 0;
2469                 }
2470                 $linkCache = LinkCache::singleton();
2471                 $this->mLength = intval( $linkCache->getGoodLinkFieldObj( $this, 'length' ) );
2472
2473                 return $this->mLength;
2474         }
2475
2476         /**
2477          * What is the page_latest field for this page?
2478          *
2479          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select for update
2480          * @return Int or 0 if the page doesn't exist
2481          */
2482         public function getLatestRevID( $flags = 0 ) {
2483                 if ( $this->mLatestID !== false ) {
2484                         return intval( $this->mLatestID );
2485                 }
2486                 # Calling getArticleID() loads the field from cache as needed
2487                 if ( !$this->getArticleID( $flags ) ) {
2488                         return $this->mLatestID = 0;
2489                 }
2490                 $linkCache = LinkCache::singleton();
2491                 $this->mLatestID = intval( $linkCache->getGoodLinkFieldObj( $this, 'revision' ) );
2492
2493                 return $this->mLatestID;
2494         }
2495
2496         /**
2497          * This clears some fields in this object, and clears any associated
2498          * keys in the "bad links" section of the link cache.
2499          *
2500          * - This is called from Article::doEdit() and Article::insertOn() to allow
2501          * loading of the new page_id. It's also called from
2502          * Article::doDeleteArticle()
2503          *
2504          * @param $newid Int the new Article ID
2505          */
2506         public function resetArticleID( $newid ) {
2507                 $linkCache = LinkCache::singleton();
2508                 $linkCache->clearBadLink( $this->getPrefixedDBkey() );
2509
2510                 if ( $newid === false ) {
2511                         $this->mArticleID = -1;
2512                 } else {
2513                         $this->mArticleID = intval( $newid );
2514                 }
2515                 $this->mRestrictionsLoaded = false;
2516                 $this->mRestrictions = array();
2517                 $this->mRedirect = null;
2518                 $this->mLength = -1;
2519                 $this->mLatestID = false;
2520         }
2521
2522         /**
2523          * Updates page_touched for this page; called from LinksUpdate.php
2524          *
2525          * @return Bool true if the update succeded
2526          */
2527         public function invalidateCache() {
2528                 if ( wfReadOnly() ) {
2529                         return;
2530                 }
2531                 $dbw = wfGetDB( DB_MASTER );
2532                 $success = $dbw->update(
2533                         'page',
2534                         array( 'page_touched' => $dbw->timestamp() ),
2535                         $this->pageCond(),
2536                         __METHOD__
2537                 );
2538                 HTMLFileCache::clearFileCache( $this );
2539                 return $success;
2540         }
2541
2542         /**
2543          * Prefix some arbitrary text with the namespace or interwiki prefix
2544          * of this object
2545          *
2546          * @param $name String the text
2547          * @return String the prefixed text
2548          * @private
2549          */
2550         private function prefix( $name ) {
2551                 $p = '';
2552                 if ( $this->mInterwiki != '' ) {
2553                         $p = $this->mInterwiki . ':';
2554                 }
2555
2556                 if ( 0 != $this->mNamespace ) {
2557                         $p .= $this->getNsText() . ':';
2558                 }
2559                 return $p . $name;
2560         }
2561
2562         /**
2563          * Returns a simple regex that will match on characters and sequences invalid in titles.
2564          * Note that this doesn't pick up many things that could be wrong with titles, but that
2565          * replacing this regex with something valid will make many titles valid.
2566          *
2567          * @return String regex string
2568          */
2569         static function getTitleInvalidRegex() {
2570                 static $rxTc = false;
2571                 if ( !$rxTc ) {
2572                         # Matching titles will be held as illegal.
2573                         $rxTc = '/' .
2574                                 # Any character not allowed is forbidden...
2575                                 '[^' . Title::legalChars() . ']' .
2576                                 # URL percent encoding sequences interfere with the ability
2577                                 # to round-trip titles -- you can't link to them consistently.
2578                                 '|%[0-9A-Fa-f]{2}' .
2579                                 # XML/HTML character references produce similar issues.
2580                                 '|&[A-Za-z0-9\x80-\xff]+;' .
2581                                 '|&#[0-9]+;' .
2582                                 '|&#x[0-9A-Fa-f]+;' .
2583                                 '/S';
2584                 }
2585
2586                 return $rxTc;
2587         }
2588
2589         /**
2590          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
2591          *
2592          * @param $text String containing title to capitalize
2593          * @param $ns int namespace index, defaults to NS_MAIN
2594          * @return String containing capitalized title
2595          */
2596         public static function capitalize( $text, $ns = NS_MAIN ) {
2597                 global $wgContLang;
2598
2599                 if ( MWNamespace::isCapitalized( $ns ) ) {
2600                         return $wgContLang->ucfirst( $text );
2601                 } else {
2602                         return $text;
2603                 }
2604         }
2605
2606         /**
2607          * Secure and split - main initialisation function for this object
2608          *
2609          * Assumes that mDbkeyform has been set, and is urldecoded
2610          * and uses underscores, but not otherwise munged.  This function
2611          * removes illegal characters, splits off the interwiki and
2612          * namespace prefixes, sets the other forms, and canonicalizes
2613          * everything.
2614          *
2615          * @return Bool true on success
2616          */
2617         private function secureAndSplit() {
2618                 global $wgContLang, $wgLocalInterwiki;
2619
2620                 # Initialisation
2621                 $this->mInterwiki = $this->mFragment = '';
2622                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
2623
2624                 $dbkey = $this->mDbkeyform;
2625
2626                 # Strip Unicode bidi override characters.
2627                 # Sometimes they slip into cut-n-pasted page titles, where the
2628                 # override chars get included in list displays.
2629                 $dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );
2630
2631                 # Clean up whitespace
2632                 # Note: use of the /u option on preg_replace here will cause
2633                 # input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
2634                 # conveniently disabling them.
2635                 $dbkey = preg_replace( '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u', '_', $dbkey );
2636                 $dbkey = trim( $dbkey, '_' );
2637
2638                 if ( $dbkey == '' ) {
2639                         return false;
2640                 }
2641
2642                 if ( false !== strpos( $dbkey, UTF8_REPLACEMENT ) ) {
2643                         # Contained illegal UTF-8 sequences or forbidden Unicode chars.
2644                         return false;
2645                 }
2646
2647                 $this->mDbkeyform = $dbkey;
2648
2649                 # Initial colon indicates main namespace rather than specified default
2650                 # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
2651                 if ( ':' == $dbkey[0] ) {
2652                         $this->mNamespace = NS_MAIN;
2653                         $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
2654                         $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
2655                 }
2656
2657                 # Namespace or interwiki prefix
2658                 $firstPass = true;
2659                 $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
2660                 do {
2661                         $m = array();
2662                         if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
2663                                 $p = $m[1];
2664                                 if ( ( $ns = $wgContLang->getNsIndex( $p ) ) !== false ) {
2665                                         # Ordinary namespace
2666                                         $dbkey = $m[2];
2667                                         $this->mNamespace = $ns;
2668                                         # For Talk:X pages, check if X has a "namespace" prefix
2669                                         if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
2670                                                 if ( $wgContLang->getNsIndex( $x[1] ) ) {
2671                                                         # Disallow Talk:File:x type titles...
2672                                                         return false;
2673                                                 } elseif ( Interwiki::isValidInterwiki( $x[1] ) ) {
2674                                                         # Disallow Talk:Interwiki:x type titles...
2675                                                         return false;
2676                                                 }
2677                                         }
2678                                 } elseif ( Interwiki::isValidInterwiki( $p ) ) {
2679                                         if ( !$firstPass ) {
2680                                                 # Can't make a local interwiki link to an interwiki link.
2681                                                 # That's just crazy!
2682                                                 return false;
2683                                         }
2684
2685                                         # Interwiki link
2686                                         $dbkey = $m[2];
2687                                         $this->mInterwiki = $wgContLang->lc( $p );
2688
2689                                         # Redundant interwiki prefix to the local wiki
2690                                         if ( $wgLocalInterwiki !== false
2691                                                 && 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki ) )
2692                                         {
2693                                                 if ( $dbkey == '' ) {
2694                                                         # Can't have an empty self-link
2695                                                         return false;
2696                                                 }
2697                                                 $this->mInterwiki = '';
2698                                                 $firstPass = false;
2699                                                 # Do another namespace split...
2700                                                 continue;
2701                                         }
2702
2703                                         # If there's an initial colon after the interwiki, that also
2704                                         # resets the default namespace
2705                                         if ( $dbkey !== '' && $dbkey[0] == ':' ) {
2706                                                 $this->mNamespace = NS_MAIN;
2707                                                 $dbkey = substr( $dbkey, 1 );
2708                                         }
2709                                 }
2710                                 # If there's no recognized interwiki or namespace,
2711                                 # then let the colon expression be part of the title.
2712                         }
2713                         break;
2714                 } while ( true );
2715
2716                 # We already know that some pages won't be in the database!
2717                 if ( $this->mInterwiki != '' || NS_SPECIAL == $this->mNamespace ) {
2718                         $this->mArticleID = 0;
2719                 }
2720                 $fragment = strstr( $dbkey, '#' );
2721                 if ( false !== $fragment ) {
2722                         $this->setFragment( $fragment );
2723                         $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
2724                         # remove whitespace again: prevents "Foo_bar_#"
2725                         # becoming "Foo_bar_"
2726                         $dbkey = preg_replace( '/_*$/', '', $dbkey );
2727                 }
2728
2729                 # Reject illegal characters.
2730                 $rxTc = self::getTitleInvalidRegex();
2731                 if ( preg_match( $rxTc, $dbkey ) ) {
2732                         return false;
2733                 }
2734
2735                 # Pages with "/./" or "/../" appearing in the URLs will often be un-
2736                 # reachable due to the way web browsers deal with 'relative' URLs.
2737                 # Also, they conflict with subpage syntax.  Forbid them explicitly.
2738                 if ( strpos( $dbkey, '.' ) !== false &&
2739                          ( $dbkey === '.' || $dbkey === '..' ||
2740                            strpos( $dbkey, './' ) === 0  ||
2741                            strpos( $dbkey, '../' ) === 0 ||
2742                            strpos( $dbkey, '/./' ) !== false ||
2743                            strpos( $dbkey, '/../' ) !== false  ||
2744                            substr( $dbkey, -2 ) == '/.' ||
2745                            substr( $dbkey, -3 ) == '/..' ) )
2746                 {
2747                         return false;
2748                 }
2749
2750                 # Magic tilde sequences? Nu-uh!
2751                 if ( strpos( $dbkey, '~~~' ) !== false ) {
2752                         return false;
2753                 }
2754
2755                 # Limit the size of titles to 255 bytes. This is typically the size of the
2756                 # underlying database field. We make an exception for special pages, which
2757                 # don't need to be stored in the database, and may edge over 255 bytes due
2758                 # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
2759                 if ( ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 ) ||
2760                   strlen( $dbkey ) > 512 )
2761                 {
2762                         return false;
2763                 }
2764
2765                 # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
2766                 # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
2767                 # other site might be case-sensitive.
2768                 $this->mUserCaseDBKey = $dbkey;
2769                 if ( $this->mInterwiki == '' ) {
2770                         $dbkey = self::capitalize( $dbkey, $this->mNamespace );
2771                 }
2772
2773                 # Can't make a link to a namespace alone... "empty" local links can only be
2774                 # self-links with a fragment identifier.
2775                 if ( $dbkey == '' && $this->mInterwiki == '' && $this->mNamespace != NS_MAIN ) {
2776                         return false;
2777                 }
2778
2779                 // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
2780                 // IP names are not allowed for accounts, and can only be referring to
2781                 // edits from the IP. Given '::' abbreviations and caps/lowercaps,
2782                 // there are numerous ways to present the same IP. Having sp:contribs scan
2783                 // them all is silly and having some show the edits and others not is
2784                 // inconsistent. Same for talk/userpages. Keep them normalized instead.
2785                 $dbkey = ( $this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK )
2786                         ? IP::sanitizeIP( $dbkey )
2787                         : $dbkey;
2788
2789                 // Any remaining initial :s are illegal.
2790                 if ( $dbkey !== '' && ':' == $dbkey { 0 } ) {
2791                         return false;
2792                 }
2793
2794                 # Fill fields
2795                 $this->mDbkeyform = $dbkey;
2796                 $this->mUrlform = wfUrlencode( $dbkey );
2797
2798                 $this->mTextform = str_replace( '_', ' ', $dbkey );
2799
2800                 return true;
2801         }
2802
2803         /**
2804          * Set the fragment for this title. Removes the first character from the
2805          * specified fragment before setting, so it assumes you're passing it with
2806          * an initial "#".
2807          *
2808          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
2809          * Still in active use privately.
2810          *
2811          * @param $fragment String text
2812          */
2813         public function setFragment( $fragment ) {
2814                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
2815         }
2816
2817         /**
2818          * Get a Title object associated with the talk page of this article
2819          *
2820          * @return Title the object for the talk page
2821          */
2822         public function getTalkPage() {
2823                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
2824         }
2825
2826         /**
2827          * Get a title object associated with the subject page of this
2828          * talk page
2829          *
2830          * @return Title the object for the subject page
2831          */
2832         public function getSubjectPage() {
2833                 // Is this the same title?
2834                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
2835                 if ( $this->getNamespace() == $subjectNS ) {
2836                         return $this;
2837                 }
2838                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
2839         }
2840
2841         /**
2842          * Get an array of Title objects linking to this Title
2843          * Also stores the IDs in the link cache.
2844          *
2845          * WARNING: do not use this function on arbitrary user-supplied titles!
2846          * On heavily-used templates it will max out the memory.
2847          *
2848          * @param $options Array: may be FOR UPDATE
2849          * @param $table String: table name
2850          * @param $prefix String: fields prefix
2851          * @return Array of Title objects linking here
2852          */
2853         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
2854                 $linkCache = LinkCache::singleton();
2855
2856                 if ( count( $options ) > 0 ) {
2857                         $db = wfGetDB( DB_MASTER );
2858                 } else {
2859                         $db = wfGetDB( DB_SLAVE );
2860                 }
2861
2862                 $res = $db->select(
2863                         array( 'page', $table ),
2864                         array( 'page_namespace', 'page_title', 'page_id', 'page_len', 'page_is_redirect', 'page_latest' ),
2865                         array(
2866                                 "{$prefix}_from=page_id",
2867                                 "{$prefix}_namespace" => $this->getNamespace(),
2868                                 "{$prefix}_title"     => $this->getDBkey() ),
2869                         __METHOD__,
2870                         $options
2871                 );
2872
2873                 $retVal = array();
2874                 if ( $db->numRows( $res ) ) {
2875                         foreach ( $res as $row ) {
2876                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
2877                                 if ( $titleObj ) {
2878                                         $linkCache->addGoodLinkObj( $row->page_id, $titleObj, $row->page_len, $row->page_is_redirect, $row->page_latest );
2879                                         $retVal[] = $titleObj;
2880                                 }
2881                         }
2882                 }
2883                 return $retVal;
2884         }
2885
2886         /**
2887          * Get an array of Title objects using this Title as a template
2888          * Also stores the IDs in the link cache.
2889          *
2890          * WARNING: do not use this function on arbitrary user-supplied titles!
2891          * On heavily-used templates it will max out the memory.
2892          *
2893          * @param $options Array: may be FOR UPDATE
2894          * @return Array of Title the Title objects linking here
2895          */
2896         public function getTemplateLinksTo( $options = array() ) {
2897                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
2898         }
2899
2900         /**
2901          * Get an array of Title objects referring to non-existent articles linked from this page
2902          *
2903          * @todo check if needed (used only in SpecialBrokenRedirects.php, and should use redirect table in this case)
2904          * @return Array of Title the Title objects
2905          */
2906         public function getBrokenLinksFrom() {
2907                 if ( $this->getArticleId() == 0 ) {
2908                         # All links from article ID 0 are false positives
2909                         return array();
2910                 }
2911
2912                 $dbr = wfGetDB( DB_SLAVE );
2913                 $res = $dbr->select(
2914                         array( 'page', 'pagelinks' ),
2915                         array( 'pl_namespace', 'pl_title' ),
2916                         array(
2917                                 'pl_from' => $this->getArticleId(),
2918                                 'page_namespace IS NULL'
2919                         ),
2920                         __METHOD__, array(),
2921                         array(
2922                                 'page' => array(
2923                                         'LEFT JOIN',
2924                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
2925                                 )
2926                         )
2927                 );
2928
2929                 $retVal = array();
2930                 foreach ( $res as $row ) {
2931                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
2932                 }
2933                 return $retVal;
2934         }
2935
2936
2937         /**
2938          * Get a list of URLs to purge from the Squid cache when this
2939          * page changes
2940          *
2941          * @return Array of String the URLs
2942          */
2943         public function getSquidURLs() {
2944                 global $wgContLang;
2945
2946                 $urls = array(
2947                         $this->getInternalURL(),
2948                         $this->getInternalURL( 'action=history' )
2949                 );
2950
2951                 // purge variant urls as well
2952                 if ( $wgContLang->hasVariants() ) {
2953                         $variants = $wgContLang->getVariants();
2954                         foreach ( $variants as $vCode ) {
2955                                 $urls[] = $this->getInternalURL( '', $vCode );
2956                         }
2957                 }
2958
2959                 return $urls;
2960         }
2961
2962         /**
2963          * Purge all applicable Squid URLs
2964          */
2965         public function purgeSquid() {
2966                 global $wgUseSquid;
2967                 if ( $wgUseSquid ) {
2968                         $urls = $this->getSquidURLs();
2969                         $u = new SquidUpdate( $urls );
2970                         $u->doUpdate();
2971                 }
2972         }
2973
2974         /**
2975          * Move this page without authentication
2976          *
2977          * @param $nt Title the new page Title
2978          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
2979          */
2980         public function moveNoAuth( &$nt ) {
2981                 return $this->moveTo( $nt, false );
2982         }
2983
2984         /**
2985          * Check whether a given move operation would be valid.
2986          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
2987          *
2988          * @param $nt Title the new title
2989          * @param $auth Bool indicates whether $wgUser's permissions
2990          *  should be checked
2991          * @param $reason String is the log summary of the move, used for spam checking
2992          * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
2993          */
2994         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
2995                 global $wgUser;
2996
2997                 $errors = array();
2998                 if ( !$nt ) {
2999                         // Normally we'd add this to $errors, but we'll get
3000                         // lots of syntax errors if $nt is not an object
3001                         return array( array( 'badtitletext' ) );
3002                 }
3003                 if ( $this->equals( $nt ) ) {
3004                         $errors[] = array( 'selfmove' );
3005                 }
3006                 if ( !$this->isMovable() ) {
3007                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3008                 }
3009                 if ( $nt->getInterwiki() != '' ) {
3010                         $errors[] = array( 'immobile-target-namespace-iw' );
3011                 }
3012                 if ( !$nt->isMovable() ) {
3013                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3014                 }
3015
3016                 $oldid = $this->getArticleID();
3017                 $newid = $nt->getArticleID();
3018
3019                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3020                         $errors[] = array( 'articleexists' );
3021                 }
3022                 if ( ( $this->getDBkey() == '' ) ||
3023                          ( !$oldid ) ||
3024                          ( $nt->getDBkey() == '' ) ) {
3025                         $errors[] = array( 'badarticleerror' );
3026                 }
3027
3028                 // Image-specific checks
3029                 if ( $this->getNamespace() == NS_FILE ) {
3030                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3031                 }
3032
3033                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3034                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3035                 }
3036
3037                 if ( $auth ) {
3038                         $errors = wfMergeErrorArrays( $errors,
3039                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3040                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3041                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3042                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3043                 }
3044
3045                 $match = EditPage::matchSummarySpamRegex( $reason );
3046                 if ( $match !== false ) {
3047                         // This is kind of lame, won't display nice
3048                         $errors[] = array( 'spamprotectiontext' );
3049                 }
3050
3051                 $err = null;
3052                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3053                         $errors[] = array( 'hookaborted', $err );
3054                 }
3055
3056                 # The move is allowed only if (1) the target doesn't exist, or
3057                 # (2) the target is a redirect to the source, and has no history
3058                 # (so we can undo bad moves right after they're done).
3059
3060                 if ( 0 != $newid ) { # Target exists; check for validity
3061                         if ( !$this->isValidMoveTarget( $nt ) ) {
3062                                 $errors[] = array( 'articleexists' );
3063                         }
3064                 } else {
3065                         $tp = $nt->getTitleProtection();
3066                         $right = ( $tp['pt_create_perm'] == 'sysop' ) ? 'protect' : $tp['pt_create_perm'];
3067                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3068                                 $errors[] = array( 'cantmove-titleprotected' );
3069                         }
3070                 }
3071                 if ( empty( $errors ) ) {
3072                         return true;
3073                 }
3074                 return $errors;
3075         }
3076
3077         /**
3078          * Check if the requested move target is a valid file move target
3079          * @param Title $nt Target title
3080          * @return array List of errors
3081          */
3082         protected function validateFileMoveOperation( $nt ) {
3083                 global $wgUser;
3084
3085                 $errors = array();
3086
3087                 if ( $nt->getNamespace() != NS_FILE ) {
3088                         $errors[] = array( 'imagenocrossnamespace' );
3089                 }
3090
3091                 $file = wfLocalFile( $this );
3092                 if ( $file->exists() ) {
3093                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3094                                 $errors[] = array( 'imageinvalidfilename' );
3095                         }
3096                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3097                                 $errors[] = array( 'imagetypemismatch' );
3098                         }
3099                 }
3100
3101                 $destFile = wfLocalFile( $nt );
3102                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3103                         $errors[] = array( 'file-exists-sharedrepo' );
3104                 }
3105
3106                 return $errors;
3107         }
3108
3109         /**
3110          * Move a title to a new location
3111          *
3112          * @param $nt Title the new title
3113          * @param $auth Bool indicates whether $wgUser's permissions
3114          *  should be checked
3115          * @param $reason String the reason for the move
3116          * @param $createRedirect Bool Whether to create a redirect from the old title to the new title.
3117          *  Ignored if the user doesn't have the suppressredirect right.
3118          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3119          */
3120         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3121                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3122                 if ( is_array( $err ) ) {
3123                         return $err;
3124                 }
3125
3126                 // If it is a file, move it first. It is done before all other moving stuff is
3127                 // done because it's hard to revert
3128                 $dbw = wfGetDB( DB_MASTER );
3129                 if ( $this->getNamespace() == NS_FILE ) {
3130                         $file = wfLocalFile( $this );
3131                         if ( $file->exists() ) {
3132                                 $status = $file->move( $nt );
3133                                 if ( !$status->isOk() ) {
3134                                         return $status->getErrorsArray();
3135                                 }
3136                         }
3137                 }
3138
3139                 $dbw->begin(); # If $file was a LocalFile, its transaction would have closed our own.
3140                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3141                 $protected = $this->isProtected();
3142                 $pageCountChange = ( $createRedirect ? 1 : 0 ) - ( $nt->exists() ? 1 : 0 );
3143
3144                 // Do the actual move
3145                 $err = $this->moveToInternal( $nt, $reason, $createRedirect );
3146                 if ( is_array( $err ) ) {
3147                         # @todo FIXME: What about the File we have already moved?
3148                         $dbw->rollback();
3149                         return $err;
3150                 }
3151
3152                 $redirid = $this->getArticleID();
3153
3154                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3155                 // cl_timestamp, which may disturb time-based lists on some sites.
3156                 $prefixes = $dbw->select(
3157                         'categorylinks',
3158                         array( 'cl_sortkey_prefix', 'cl_to' ),
3159                         array( 'cl_from' => $pageid ),
3160                         __METHOD__
3161                 );
3162                 foreach ( $prefixes as $prefixRow ) {
3163                         $prefix = $prefixRow->cl_sortkey_prefix;
3164                         $catTo = $prefixRow->cl_to;
3165                         $dbw->update( 'categorylinks',
3166                                 array(
3167                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3168                                                 $nt->getCategorySortkey( $prefix ) ),
3169                                         'cl_timestamp=cl_timestamp' ),
3170                                 array(
3171                                         'cl_from' => $pageid,
3172                                         'cl_to' => $catTo ),
3173                                 __METHOD__
3174                         );
3175                 }
3176
3177                 if ( $protected ) {
3178                         # Protect the redirect title as the title used to be...
3179                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3180                                 array(
3181                                         'pr_page'    => $redirid,
3182                                         'pr_type'    => 'pr_type',
3183                                         'pr_level'   => 'pr_level',
3184                                         'pr_cascade' => 'pr_cascade',
3185                                         'pr_user'    => 'pr_user',
3186                                         'pr_expiry'  => 'pr_expiry'
3187                                 ),
3188                                 array( 'pr_page' => $pageid ),
3189                                 __METHOD__,
3190                                 array( 'IGNORE' )
3191                         );
3192                         # Update the protection log
3193                         $log = new LogPage( 'protect' );
3194                         $comment = wfMsgForContent( 'prot_1movedto2', $this->getPrefixedText(), $nt->getPrefixedText() );
3195                         if ( $reason ) {
3196                                 $comment .= wfMsgForContent( 'colon-separator' ) . $reason;
3197                         }
3198                         // @todo FIXME: $params?
3199                         $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ) );
3200                 }
3201
3202                 # Update watchlists
3203                 $oldnamespace = $this->getNamespace() & ~1;
3204                 $newnamespace = $nt->getNamespace() & ~1;
3205                 $oldtitle = $this->getDBkey();
3206                 $newtitle = $nt->getDBkey();
3207
3208                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3209                         WatchedItem::duplicateEntries( $this, $nt );
3210                 }
3211
3212                 # Update search engine
3213                 $u = new SearchUpdate( $pageid, $nt->getPrefixedDBkey() );
3214                 $u->doUpdate();
3215                 $u = new SearchUpdate( $redirid, $this->getPrefixedDBkey(), '' );
3216                 $u->doUpdate();
3217
3218                 $dbw->commit();
3219
3220                 # Update site_stats
3221                 if ( $this->isContentPage() && !$nt->isContentPage() ) {
3222                         # No longer a content page
3223                         # Not viewed, edited, removing
3224                         $u = new SiteStatsUpdate( 0, 1, -1, $pageCountChange );
3225                 } elseif ( !$this->isContentPage() && $nt->isContentPage() ) {
3226                         # Now a content page
3227                         # Not viewed, edited, adding
3228                         $u = new SiteStatsUpdate( 0, 1, + 1, $pageCountChange );
3229                 } elseif ( $pageCountChange ) {
3230                         # Redirect added
3231                         $u = new SiteStatsUpdate( 0, 0, 0, 1 );
3232                 } else {
3233                         # Nothing special
3234                         $u = false;
3235                 }
3236                 if ( $u ) {
3237                         $u->doUpdate();
3238                 }
3239                 # Update message cache for interface messages
3240                 if ( $this->getNamespace() == NS_MEDIAWIKI ) {
3241                         # @bug 17860: old article can be deleted, if this the case,
3242                         # delete it from message cache
3243                         if ( $this->getArticleID() === 0 ) {
3244                                 MessageCache::singleton()->replace( $this->getDBkey(), false );
3245                         } else {
3246                                 $oldarticle = new Article( $this );
3247                                 MessageCache::singleton()->replace( $this->getDBkey(), $oldarticle->getContent() );
3248                         }
3249                 }
3250                 if ( $nt->getNamespace() == NS_MEDIAWIKI ) {
3251                         $newarticle = new Article( $nt );
3252                         MessageCache::singleton()->replace( $nt->getDBkey(), $newarticle->getContent() );
3253                 }
3254
3255                 global $wgUser;
3256                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
3257                 return true;
3258         }
3259
3260         /**
3261          * Move page to a title which is either a redirect to the
3262          * source page or nonexistent
3263          *
3264          * @param $nt Title the page to move to, which should be a redirect or nonexistent
3265          * @param $reason String The reason for the move
3266          * @param $createRedirect Bool Whether to leave a redirect at the old title.  Ignored
3267          *   if the user doesn't have the suppressredirect right
3268          */
3269         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3270                 global $wgUser, $wgContLang;
3271
3272                 $moveOverRedirect = $nt->exists();
3273
3274                 $commentMsg = ( $moveOverRedirect ? '1movedto2_redir' : '1movedto2' );
3275                 $comment = wfMsgForContent( $commentMsg, $this->getPrefixedText(), $nt->getPrefixedText() );
3276
3277                 if ( $reason ) {
3278                         $comment .= wfMsgForContent( 'colon-separator' ) . $reason;
3279                 }
3280                 # Truncate for whole multibyte characters.
3281                 $comment = $wgContLang->truncate( $comment, 255 );
3282
3283                 $oldid = $this->getArticleID();
3284                 $latest = $this->getLatestRevID();
3285
3286                 $oldns = $this->getNamespace();
3287                 $olddbk = $this->getDBkey();
3288
3289                 $dbw = wfGetDB( DB_MASTER );
3290
3291                 if ( $moveOverRedirect ) {
3292                         $rcts = $dbw->timestamp( $nt->getEarliestRevTime() );
3293
3294                         $newid = $nt->getArticleID();
3295                         $newns = $nt->getNamespace();
3296                         $newdbk = $nt->getDBkey();
3297
3298                         # Delete the old redirect. We don't save it to history since
3299                         # by definition if we've got here it's rather uninteresting.
3300                         # We have to remove it so that the next step doesn't trigger
3301                         # a conflict on the unique namespace+title index...
3302                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3303                         if ( !$dbw->cascadingDeletes() ) {
3304                                 $dbw->delete( 'revision', array( 'rev_page' => $newid ), __METHOD__ );
3305                                 global $wgUseTrackbacks;
3306                                 if ( $wgUseTrackbacks ) {
3307                                         $dbw->delete( 'trackbacks', array( 'tb_page' => $newid ), __METHOD__ );
3308                                 }
3309                                 $dbw->delete( 'pagelinks', array( 'pl_from' => $newid ), __METHOD__ );
3310                                 $dbw->delete( 'imagelinks', array( 'il_from' => $newid ), __METHOD__ );
3311                                 $dbw->delete( 'categorylinks', array( 'cl_from' => $newid ), __METHOD__ );
3312                                 $dbw->delete( 'templatelinks', array( 'tl_from' => $newid ), __METHOD__ );
3313                                 $dbw->delete( 'externallinks', array( 'el_from' => $newid ), __METHOD__ );
3314                                 $dbw->delete( 'langlinks', array( 'll_from' => $newid ), __METHOD__ );
3315                                 $dbw->delete( 'redirect', array( 'rd_from' => $newid ), __METHOD__ );
3316                         }
3317                         // If the target page was recently created, it may have an entry in recentchanges still
3318                         $dbw->delete( 'recentchanges',
3319                                 array( 'rc_timestamp' => $rcts, 'rc_namespace' => $newns, 'rc_title' => $newdbk, 'rc_new' => 1 ),
3320                                 __METHOD__
3321                         );
3322                 }
3323
3324                 # Save a null revision in the page's history notifying of the move
3325                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
3326                 if ( !is_object( $nullRevision ) ) {
3327                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3328                 }
3329                 $nullRevId = $nullRevision->insertOn( $dbw );
3330
3331                 # Change the name of the target page:
3332                 $dbw->update( 'page',
3333                         /* SET */ array(
3334                                 'page_touched'   => $dbw->timestamp(),
3335                                 'page_namespace' => $nt->getNamespace(),
3336                                 'page_title'     => $nt->getDBkey(),
3337                                 'page_latest'    => $nullRevId,
3338                         ),
3339                         /* WHERE */ array( 'page_id' => $oldid ),
3340                         __METHOD__
3341                 );
3342                 $nt->resetArticleID( $oldid );
3343
3344                 $article = new Article( $nt );
3345                 wfRunHooks( 'NewRevisionFromEditComplete', array( $article, $nullRevision, $latest, $wgUser ) );
3346
3347                 # Recreate the redirect, this time in the other direction.
3348                 if ( $createRedirect || !$wgUser->isAllowed( 'suppressredirect' ) ) {
3349                         $mwRedir = MagicWord::get( 'redirect' );
3350                         $redirectText = $mwRedir->getSynonym( 0 ) . ' [[' . $nt->getPrefixedText() . "]]\n";
3351                         $redirectArticle = new Article( $this );
3352                         $newid = $redirectArticle->insertOn( $dbw );
3353                         $redirectRevision = new Revision( array(
3354                                 'page'    => $newid,
3355                                 'comment' => $comment,
3356                                 'text'    => $redirectText ) );
3357                         $redirectRevision->insertOn( $dbw );
3358                         $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
3359
3360                         wfRunHooks( 'NewRevisionFromEditComplete', array( $redirectArticle, $redirectRevision, false, $wgUser ) );
3361
3362                         # Now, we record the link from the redirect to the new title.
3363                         # It should have no other outgoing links...
3364                         $dbw->delete( 'pagelinks', array( 'pl_from' => $newid ), __METHOD__ );
3365                         $dbw->insert( 'pagelinks',
3366                                 array(
3367                                         'pl_from'      => $newid,
3368                                         'pl_namespace' => $nt->getNamespace(),
3369                                         'pl_title'     => $nt->getDBkey() ),
3370                                 __METHOD__ );
3371                         $redirectSuppressed = false;
3372                 } else {
3373                         // Get rid of old new page entries in Special:NewPages and RC.
3374                         // Needs to be before $this->resetArticleID( 0 ).
3375                         $dbw->delete( 'recentchanges', array(
3376                                         'rc_timestamp' => $dbw->timestamp( $this->getEarliestRevTime() ),
3377                                         'rc_namespace' => $oldns,
3378                                         'rc_title' => $olddbk,
3379                                         'rc_new' => 1
3380                                 ),
3381                                 __METHOD__
3382                         );
3383
3384                         $this->resetArticleID( 0 );
3385                         $redirectSuppressed = true;
3386                 }
3387
3388                 # Log the move
3389                 $log = new LogPage( 'move' );
3390                 $logType = ( $moveOverRedirect ? 'move_redir' : 'move' );
3391                 $log->addEntry( $logType, $this, $reason, array( 1 => $nt->getPrefixedText(), 2 => $redirectSuppressed ) );
3392
3393                 # Purge caches for old and new titles
3394                 if ( $moveOverRedirect ) {
3395                         # A simple purge is enough when moving over a redirect
3396                         $nt->purgeSquid();
3397                 } else {
3398                         # Purge caches as per article creation, including any pages that link to this title
3399                         Article::onArticleCreate( $nt );
3400                 }
3401                 $this->purgeSquid();
3402         }
3403
3404         /**
3405          * Move this page's subpages to be subpages of $nt
3406          *
3407          * @param $nt Title Move target
3408          * @param $auth bool Whether $wgUser's permissions should be checked
3409          * @param $reason string The reason for the move
3410          * @param $createRedirect bool Whether to create redirects from the old subpages to
3411          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3412          * @return mixed array with old page titles as keys, and strings (new page titles) or
3413          *     arrays (errors) as values, or an error array with numeric indices if no pages
3414          *     were moved
3415          */
3416         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3417                 global $wgMaximumMovedPages;
3418                 // Check permissions
3419                 if ( !$this->userCan( 'move-subpages' ) ) {
3420                         return array( 'cant-move-subpages' );
3421                 }
3422                 // Do the source and target namespaces support subpages?
3423                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3424                         return array( 'namespace-nosubpages',
3425                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3426                 }
3427                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3428                         return array( 'namespace-nosubpages',
3429                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3430                 }
3431
3432                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3433                 $retval = array();
3434                 $count = 0;
3435                 foreach ( $subpages as $oldSubpage ) {
3436                         $count++;
3437                         if ( $count > $wgMaximumMovedPages ) {
3438                                 $retval[$oldSubpage->getPrefixedTitle()] =
3439                                                 array( 'movepage-max-pages',
3440                                                         $wgMaximumMovedPages );
3441                                 break;
3442                         }
3443
3444                         // We don't know whether this function was called before
3445                         // or after moving the root page, so check both
3446                         // $this and $nt
3447                         if ( $oldSubpage->getArticleId() == $this->getArticleId() ||
3448                                         $oldSubpage->getArticleID() == $nt->getArticleId() )
3449                         {
3450                                 // When moving a page to a subpage of itself,
3451                                 // don't move it twice
3452                                 continue;
3453                         }
3454                         $newPageName = preg_replace(
3455                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3456                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3457                                         $oldSubpage->getDBkey() );
3458                         if ( $oldSubpage->isTalkPage() ) {
3459                                 $newNs = $nt->getTalkPage()->getNamespace();
3460                         } else {
3461                                 $newNs = $nt->getSubjectPage()->getNamespace();
3462                         }
3463                         # Bug 14385: we need makeTitleSafe because the new page names may
3464                         # be longer than 255 characters.
3465                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3466
3467                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3468                         if ( $success === true ) {
3469                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3470                         } else {
3471                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3472                         }
3473                 }
3474                 return $retval;
3475         }
3476
3477         /**
3478          * Checks if this page is just a one-rev redirect.
3479          * Adds lock, so don't use just for light purposes.
3480          *
3481          * @return Bool
3482          */
3483         public function isSingleRevRedirect() {
3484                 $dbw = wfGetDB( DB_MASTER );
3485                 # Is it a redirect?
3486                 $row = $dbw->selectRow( 'page',
3487                         array( 'page_is_redirect', 'page_latest', 'page_id' ),
3488                         $this->pageCond(),
3489                         __METHOD__,
3490                         array( 'FOR UPDATE' )
3491                 );
3492                 # Cache some fields we may want
3493                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3494                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3495                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3496                 if ( !$this->mRedirect ) {
3497                         return false;
3498                 }
3499                 # Does the article have a history?
3500                 $row = $dbw->selectField( array( 'page', 'revision' ),
3501                         'rev_id',
3502                         array( 'page_namespace' => $this->getNamespace(),
3503                                 'page_title' => $this->getDBkey(),
3504                                 'page_id=rev_page',
3505                                 'page_latest != rev_id'
3506                         ),
3507                         __METHOD__,
3508                         array( 'FOR UPDATE' )
3509                 );
3510                 # Return true if there was no history
3511                 return ( $row === false );
3512         }
3513
3514         /**
3515          * Checks if $this can be moved to a given Title
3516          * - Selects for update, so don't call it unless you mean business
3517          *
3518          * @param $nt Title the new title to check
3519          * @return Bool
3520          */
3521         public function isValidMoveTarget( $nt ) {
3522                 # Is it an existing file?
3523                 if ( $nt->getNamespace() == NS_FILE ) {
3524                         $file = wfLocalFile( $nt );
3525                         if ( $file->exists() ) {
3526                                 wfDebug( __METHOD__ . ": file exists\n" );
3527                                 return false;
3528                         }
3529                 }
3530                 # Is it a redirect with no history?
3531                 if ( !$nt->isSingleRevRedirect() ) {
3532                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3533                         return false;
3534                 }
3535                 # Get the article text
3536                 $rev = Revision::newFromTitle( $nt );
3537                 $text = $rev->getText();
3538                 # Does the redirect point to the source?
3539                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3540                 $m = array();
3541                 if ( preg_match( "/\\[\\[\\s*([^\\]\\|]*)]]/", $text, $m ) ) {
3542                         $redirTitle = Title::newFromText( $m[1] );
3543                         if ( !is_object( $redirTitle ) ||
3544                                 ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3545                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) ) {
3546                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3547                                 return false;
3548                         }
3549                 } else {
3550                         # Fail safe
3551                         wfDebug( __METHOD__ . ": failsafe\n" );
3552                         return false;
3553                 }
3554                 return true;
3555         }
3556
3557         /**
3558          * Can this title be added to a user's watchlist?
3559          *
3560          * @return Bool TRUE or FALSE
3561          */
3562         public function isWatchable() {
3563                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
3564         }
3565
3566         /**
3567          * Get categories to which this Title belongs and return an array of
3568          * categories' names.
3569          *
3570          * @return Array of parents in the form:
3571          *        $parent => $currentarticle
3572          */
3573         public function getParentCategories() {
3574                 global $wgContLang;
3575
3576                 $data = array();
3577
3578                 $titleKey = $this->getArticleId();
3579
3580                 if ( $titleKey === 0 ) {
3581                         return $data;
3582                 }
3583
3584                 $dbr = wfGetDB( DB_SLAVE );
3585
3586                 $res = $dbr->select( 'categorylinks', '*',
3587                         array(
3588                                 'cl_from' => $titleKey,
3589                         ),
3590                         __METHOD__,
3591                         array()
3592                 );
3593
3594                 if ( $dbr->numRows( $res ) > 0 ) {
3595                         foreach ( $res as $row ) {
3596                                 // $data[] = Title::newFromText($wgContLang->getNSText ( NS_CATEGORY ).':'.$row->cl_to);
3597                                 $data[$wgContLang->getNSText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3598                         }
3599                 }
3600                 return $data;
3601         }
3602
3603         /**
3604          * Get a tree of parent categories
3605          *
3606          * @param $children Array with the children in the keys, to check for circular refs
3607          * @return Array Tree of parent categories
3608          */
3609         public function getParentCategoryTree( $children = array() ) {
3610                 $stack = array();
3611                 $parents = $this->getParentCategories();
3612
3613                 if ( $parents ) {
3614                         foreach ( $parents as $parent => $current ) {
3615                                 if ( array_key_exists( $parent, $children ) ) {
3616                                         # Circular reference
3617                                         $stack[$parent] = array();
3618                                 } else {
3619                                         $nt = Title::newFromText( $parent );
3620                                         if ( $nt ) {
3621                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
3622                                         }
3623                                 }
3624                         }
3625                 }
3626
3627                 return $stack;
3628         }
3629
3630         /**
3631          * Get an associative array for selecting this title from
3632          * the "page" table
3633          *
3634          * @return Array suitable for the $where parameter of DB::select()
3635          */
3636         public function pageCond() {
3637                 if ( $this->mArticleID > 0 ) {
3638                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3639                         return array( 'page_id' => $this->mArticleID );
3640                 } else {
3641                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
3642                 }
3643         }
3644
3645         /**
3646          * Get the revision ID of the previous revision
3647          *
3648          * @param $revId Int Revision ID. Get the revision that was before this one.
3649          * @param $flags Int Title::GAID_FOR_UPDATE
3650          * @return Int|Bool Old revision ID, or FALSE if none exists
3651          */
3652         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3653                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3654                 return $db->selectField( 'revision', 'rev_id',
3655                         array(
3656                                 'rev_page' => $this->getArticleId( $flags ),
3657                                 'rev_id < ' . intval( $revId )
3658                         ),
3659                         __METHOD__,
3660                         array( 'ORDER BY' => 'rev_id DESC' )
3661                 );
3662         }
3663
3664         /**
3665          * Get the revision ID of the next revision
3666          *
3667          * @param $revId Int Revision ID. Get the revision that was after this one.
3668          * @param $flags Int Title::GAID_FOR_UPDATE
3669          * @return Int|Bool Next revision ID, or FALSE if none exists
3670          */
3671         public function getNextRevisionID( $revId, $flags = 0 ) {
3672                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3673                 return $db->selectField( 'revision', 'rev_id',
3674                         array(
3675                                 'rev_page' => $this->getArticleId( $flags ),
3676                                 'rev_id > ' . intval( $revId )
3677                         ),
3678                         __METHOD__,
3679                         array( 'ORDER BY' => 'rev_id' )
3680                 );
3681         }
3682
3683         /**
3684          * Get the first revision of the page
3685          *
3686          * @param $flags Int Title::GAID_FOR_UPDATE
3687          * @return Revision|Null if page doesn't exist
3688          */
3689         public function getFirstRevision( $flags = 0 ) {
3690                 $pageId = $this->getArticleId( $flags );
3691                 if ( $pageId ) {
3692                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3693                         $row = $db->selectRow( 'revision', '*',
3694                                 array( 'rev_page' => $pageId ),
3695                                 __METHOD__,
3696                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
3697                         );
3698                         if ( $row ) {
3699                                 return new Revision( $row );
3700                         }
3701                 }
3702                 return null;
3703         }
3704
3705         /**
3706          * Get the oldest revision timestamp of this page
3707          *
3708          * @param $flags Int Title::GAID_FOR_UPDATE
3709          * @return String: MW timestamp
3710          */
3711         public function getEarliestRevTime( $flags = 0 ) {
3712                 $rev = $this->getFirstRevision( $flags );
3713                 return $rev ? $rev->getTimestamp() : null;
3714         }
3715
3716         /**
3717          * Check if this is a new page
3718          *
3719          * @return bool
3720          */
3721         public function isNewPage() {
3722                 $dbr = wfGetDB( DB_SLAVE );
3723                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
3724         }
3725
3726         /**
3727          * Get the number of revisions between the given revision.
3728          * Used for diffs and other things that really need it.
3729          *
3730          * @param $old int|Revision Old revision or rev ID (first before range)
3731          * @param $new int|Revision New revision or rev ID (first after range)
3732          * @return Int Number of revisions between these revisions.
3733          */
3734         public function countRevisionsBetween( $old, $new ) {
3735                 if ( !( $old instanceof Revision ) ) {
3736                         $old = Revision::newFromTitle( $this, (int)$old );
3737                 }
3738                 if ( !( $new instanceof Revision ) ) {
3739                         $new = Revision::newFromTitle( $this, (int)$new );
3740                 }
3741                 if ( !$old || !$new ) {
3742                         return 0; // nothing to compare
3743                 }
3744                 $dbr = wfGetDB( DB_SLAVE );
3745                 return (int)$dbr->selectField( 'revision', 'count(*)',
3746                         array(
3747                                 'rev_page' => $this->getArticleId(),
3748                                 'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
3749                                 'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
3750                         ),
3751                         __METHOD__
3752                 );
3753         }
3754
3755         /**
3756          * Get the number of authors between the given revision IDs.
3757          * Used for diffs and other things that really need it.
3758          *
3759          * @param $old int|Revision Old revision or rev ID (first before range)
3760          * @param $new int|Revision New revision or rev ID (first after range)
3761          * @param $limit Int Maximum number of authors
3762          * @return Int Number of revision authors between these revisions.
3763          */
3764         public function countAuthorsBetween( $old, $new, $limit ) {
3765                 if ( !( $old instanceof Revision ) ) {
3766                         $old = Revision::newFromTitle( $this, (int)$old );
3767                 }
3768                 if ( !( $new instanceof Revision ) ) {
3769                         $new = Revision::newFromTitle( $this, (int)$new );
3770                 }
3771                 if ( !$old || !$new ) {
3772                         return 0; // nothing to compare
3773                 }
3774                 $dbr = wfGetDB( DB_SLAVE );
3775                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
3776                         array(
3777                                 'rev_page' => $this->getArticleID(),
3778                                 'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
3779                                 'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
3780                         ), __METHOD__,
3781                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
3782                 );
3783                 return (int)$dbr->numRows( $res );
3784         }
3785
3786         /**
3787          * Compare with another title.
3788          *
3789          * @param $title Title
3790          * @return Bool
3791          */
3792         public function equals( Title $title ) {
3793                 // Note: === is necessary for proper matching of number-like titles.
3794                 return $this->getInterwiki() === $title->getInterwiki()
3795                         && $this->getNamespace() == $title->getNamespace()
3796                         && $this->getDBkey() === $title->getDBkey();
3797         }
3798
3799         /**
3800          * Callback for usort() to do title sorts by (namespace, title)
3801          *
3802          * @param $a Title
3803          * @param $b Title
3804          *
3805          * @return Integer: result of string comparison, or namespace comparison
3806          */
3807         public static function compare( $a, $b ) {
3808                 if ( $a->getNamespace() == $b->getNamespace() ) {
3809                         return strcmp( $a->getText(), $b->getText() );
3810                 } else {
3811                         return $a->getNamespace() - $b->getNamespace();
3812                 }
3813         }
3814
3815         /**
3816          * Return a string representation of this title
3817          *
3818          * @return String representation of this title
3819          */
3820         public function __toString() {
3821                 return $this->getPrefixedText();
3822         }
3823
3824         /**
3825          * Check if page exists.  For historical reasons, this function simply
3826          * checks for the existence of the title in the page table, and will
3827          * thus return false for interwiki links, special pages and the like.
3828          * If you want to know if a title can be meaningfully viewed, you should
3829          * probably call the isKnown() method instead.
3830          *
3831          * @return Bool
3832          */
3833         public function exists() {
3834                 return $this->getArticleId() != 0;
3835         }
3836
3837         /**
3838          * Should links to this title be shown as potentially viewable (i.e. as
3839          * "bluelinks"), even if there's no record by this title in the page
3840          * table?
3841          *
3842          * This function is semi-deprecated for public use, as well as somewhat
3843          * misleadingly named.  You probably just want to call isKnown(), which
3844          * calls this function internally.
3845          *
3846          * (ISSUE: Most of these checks are cheap, but the file existence check
3847          * can potentially be quite expensive.  Including it here fixes a lot of
3848          * existing code, but we might want to add an optional parameter to skip
3849          * it and any other expensive checks.)
3850          *
3851          * @return Bool
3852          */
3853         public function isAlwaysKnown() {
3854                 if ( $this->mInterwiki != '' ) {
3855                         return true;  // any interwiki link might be viewable, for all we know
3856                 }
3857                 switch( $this->mNamespace ) {
3858                         case NS_MEDIA:
3859                         case NS_FILE:
3860                                 // file exists, possibly in a foreign repo
3861                                 return (bool)wfFindFile( $this );
3862                         case NS_SPECIAL:
3863                                 // valid special page
3864                                 return SpecialPageFactory::exists( $this->getDBkey() );
3865                         case NS_MAIN:
3866                                 // selflink, possibly with fragment
3867                                 return $this->mDbkeyform == '';
3868                         case NS_MEDIAWIKI:
3869                                 // known system message
3870                                 return $this->getDefaultMessageText() !== false;
3871                         default:
3872                                 return false;
3873                 }
3874         }
3875
3876         /**
3877          * Does this title refer to a page that can (or might) be meaningfully
3878          * viewed?  In particular, this function may be used to determine if
3879          * links to the title should be rendered as "bluelinks" (as opposed to
3880          * "redlinks" to non-existent pages).
3881          *
3882          * @return Bool
3883          */
3884         public function isKnown() {
3885                 return $this->isAlwaysKnown() || $this->exists();
3886         }
3887
3888         /**
3889          * Does this page have source text?
3890          *
3891          * @return Boolean
3892          */
3893         public function hasSourceText() {
3894                 if ( $this->exists() ) {
3895                         return true;
3896                 }
3897
3898                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
3899                         // If the page doesn't exist but is a known system message, default
3900                         // message content will be displayed, same for language subpages
3901                         return $this->getDefaultMessageText() !== false;
3902                 }
3903
3904                 return false;
3905         }
3906
3907         /**
3908          * Get the default message text or false if the message doesn't exist
3909          *
3910          * @return String or false
3911          */
3912         public function getDefaultMessageText() {
3913                 global $wgContLang;
3914
3915                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
3916                         return false;
3917                 }
3918
3919                 list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
3920                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
3921
3922                 if ( $message->exists() ) {
3923                         return $message->plain();
3924                 } else {
3925                         return false;
3926                 }
3927         }
3928
3929         /**
3930          * Is this in a namespace that allows actual pages?
3931          *
3932          * @return Bool
3933          * @internal note -- uses hardcoded namespace index instead of constants
3934          */
3935         public function canExist() {
3936                 return $this->mNamespace >= 0 && $this->mNamespace != NS_MEDIA;
3937         }
3938
3939         /**
3940          * Update page_touched timestamps and send squid purge messages for
3941          * pages linking to this title. May be sent to the job queue depending
3942          * on the number of links. Typically called on create and delete.
3943          */
3944         public function touchLinks() {
3945                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
3946                 $u->doUpdate();
3947
3948                 if ( $this->getNamespace() == NS_CATEGORY ) {
3949                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
3950                         $u->doUpdate();
3951                 }
3952         }
3953
3954         /**
3955          * Get the last touched timestamp
3956          *
3957          * @param $db DatabaseBase: optional db
3958          * @return String last-touched timestamp
3959          */
3960         public function getTouched( $db = null ) {
3961                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
3962                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
3963                 return $touched;
3964         }
3965
3966         /**
3967          * Get the timestamp when this page was updated since the user last saw it.
3968          *
3969          * @param $user User
3970          * @return String|Null
3971          */
3972         public function getNotificationTimestamp( $user = null ) {
3973                 global $wgUser, $wgShowUpdatedMarker;
3974                 // Assume current user if none given
3975                 if ( !$user ) {
3976                         $user = $wgUser;
3977                 }
3978                 // Check cache first
3979                 $uid = $user->getId();
3980                 // avoid isset here, as it'll return false for null entries
3981                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
3982                         return $this->mNotificationTimestamp[$uid];
3983                 }
3984                 if ( !$uid || !$wgShowUpdatedMarker ) {
3985                         return $this->mNotificationTimestamp[$uid] = false;
3986                 }
3987                 // Don't cache too much!
3988                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
3989                         $this->mNotificationTimestamp = array();
3990                 }
3991                 $dbr = wfGetDB( DB_SLAVE );
3992                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
3993                         'wl_notificationtimestamp',
3994                         array( 'wl_namespace' => $this->getNamespace(),
3995                                 'wl_title' => $this->getDBkey(),
3996                                 'wl_user' => $user->getId()
3997                         ),
3998                         __METHOD__
3999                 );
4000                 return $this->mNotificationTimestamp[$uid];
4001         }
4002
4003         /**
4004          * Get the trackback URL for this page
4005          *
4006          * @return String Trackback URL
4007          */
4008         public function trackbackURL() {
4009                 global $wgScriptPath, $wgServer, $wgScriptExtension;
4010
4011                 return "$wgServer$wgScriptPath/trackback$wgScriptExtension?article="
4012                         . htmlspecialchars( urlencode( $this->getPrefixedDBkey() ) );
4013         }
4014
4015         /**
4016          * Get the trackback RDF for this page
4017          *
4018          * @return String Trackback RDF
4019          */
4020         public function trackbackRDF() {
4021                 $url = htmlspecialchars( $this->getFullURL() );
4022                 $title = htmlspecialchars( $this->getText() );
4023                 $tburl = $this->trackbackURL();
4024
4025                 // Autodiscovery RDF is placed in comments so HTML validator
4026                 // won't barf. This is a rather icky workaround, but seems
4027                 // frequently used by this kind of RDF thingy.
4028                 //
4029                 // Spec: http://www.sixapart.com/pronet/docs/trackback_spec
4030                 return "<!--
4031 <rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\"
4032                  xmlns:dc=\"http://purl.org/dc/elements/1.1/\"
4033                  xmlns:trackback=\"http://madskills.com/public/xml/rss/module/trackback/\">
4034 <rdf:Description
4035    rdf:about=\"$url\"
4036    dc:identifier=\"$url\"
4037    dc:title=\"$title\"
4038    trackback:ping=\"$tburl\" />
4039 </rdf:RDF>
4040 -->";
4041         }
4042
4043         /**
4044          * Generate strings used for xml 'id' names in monobook tabs
4045          *
4046          * @param $prepend string defaults to 'nstab-'
4047          * @return String XML 'id' name
4048          */
4049         public function getNamespaceKey( $prepend = 'nstab-' ) {
4050                 global $wgContLang;
4051                 // Gets the subject namespace if this title
4052                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4053                 // Checks if cononical namespace name exists for namespace
4054                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4055                         // Uses canonical namespace name
4056                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4057                 } else {
4058                         // Uses text of namespace
4059                         $namespaceKey = $this->getSubjectNsText();
4060                 }
4061                 // Makes namespace key lowercase
4062                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4063                 // Uses main
4064                 if ( $namespaceKey == '' ) {
4065                         $namespaceKey = 'main';
4066                 }
4067                 // Changes file to image for backwards compatibility
4068                 if ( $namespaceKey == 'file' ) {
4069                         $namespaceKey = 'image';
4070                 }
4071                 return $prepend . $namespaceKey;
4072         }
4073
4074         /**
4075          * Returns true if this is a special page.
4076          *
4077          * @return boolean
4078          */
4079         public function isSpecialPage() {
4080                 return $this->getNamespace() == NS_SPECIAL;
4081         }
4082
4083         /**
4084          * Returns true if this title resolves to the named special page
4085          *
4086          * @param $name String The special page name
4087          * @return boolean
4088          */
4089         public function isSpecial( $name ) {
4090                 if ( $this->getNamespace() == NS_SPECIAL ) {
4091                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
4092                         if ( $name == $thisName ) {
4093                                 return true;
4094                         }
4095                 }
4096                 return false;
4097         }
4098
4099         /**
4100          * If the Title refers to a special page alias which is not the local default, resolve
4101          * the alias, and localise the name as necessary.  Otherwise, return $this
4102          *
4103          * @return Title
4104          */
4105         public function fixSpecialName() {
4106                 if ( $this->getNamespace() == NS_SPECIAL ) {
4107                         list( $canonicalName, /*...*/ ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
4108                         if ( $canonicalName ) {
4109                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName );
4110                                 if ( $localName != $this->mDbkeyform ) {
4111                                         return Title::makeTitle( NS_SPECIAL, $localName );
4112                                 }
4113                         }
4114                 }
4115                 return $this;
4116         }
4117
4118         /**
4119          * Is this Title in a namespace which contains content?
4120          * In other words, is this a content page, for the purposes of calculating
4121          * statistics, etc?
4122          *
4123          * @return Boolean
4124          */
4125         public function isContentPage() {
4126                 return MWNamespace::isContent( $this->getNamespace() );
4127         }
4128
4129         /**
4130          * Get all extant redirects to this Title
4131          *
4132          * @param $ns Int|Null Single namespace to consider; NULL to consider all namespaces
4133          * @return Array of Title redirects to this title
4134          */
4135         public function getRedirectsHere( $ns = null ) {
4136                 $redirs = array();
4137
4138                 $dbr = wfGetDB( DB_SLAVE );
4139                 $where = array(
4140                         'rd_namespace' => $this->getNamespace(),
4141                         'rd_title' => $this->getDBkey(),
4142                         'rd_from = page_id'
4143                 );
4144                 if ( !is_null( $ns ) ) {
4145                         $where['page_namespace'] = $ns;
4146                 }
4147
4148                 $res = $dbr->select(
4149                         array( 'redirect', 'page' ),
4150                         array( 'page_namespace', 'page_title' ),
4151                         $where,
4152                         __METHOD__
4153                 );
4154
4155                 foreach ( $res as $row ) {
4156                         $redirs[] = self::newFromRow( $row );
4157                 }
4158                 return $redirs;
4159         }
4160
4161         /**
4162          * Check if this Title is a valid redirect target
4163          *
4164          * @return Bool
4165          */
4166         public function isValidRedirectTarget() {
4167                 global $wgInvalidRedirectTargets;
4168
4169                 // invalid redirect targets are stored in a global array, but explicity disallow Userlogout here
4170                 if ( $this->isSpecial( 'Userlogout' ) ) {
4171                         return false;
4172                 }
4173
4174                 foreach ( $wgInvalidRedirectTargets as $target ) {
4175                         if ( $this->isSpecial( $target ) ) {
4176                                 return false;
4177                         }
4178                 }
4179
4180                 return true;
4181         }
4182
4183         /**
4184          * Get a backlink cache object
4185          *
4186          * @return object BacklinkCache
4187          */
4188         function getBacklinkCache() {
4189                 if ( is_null( $this->mBacklinkCache ) ) {
4190                         $this->mBacklinkCache = new BacklinkCache( $this );
4191                 }
4192                 return $this->mBacklinkCache;
4193         }
4194
4195         /**
4196          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4197          *
4198          * @return Boolean
4199          */
4200         public function canUseNoindex() {
4201                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4202
4203                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4204                         ? $wgContentNamespaces
4205                         : $wgExemptFromUserRobotsControl;
4206
4207                 return !in_array( $this->mNamespace, $bannedNamespaces );
4208
4209         }
4210
4211         /**
4212          * Returns restriction types for the current Title
4213          *
4214          * @return array applicable restriction types
4215          */
4216         public function getRestrictionTypes() {
4217                 if ( $this->getNamespace() == NS_SPECIAL ) {
4218                         return array();
4219                 }
4220
4221                 $types = self::getFilteredRestrictionTypes( $this->exists() );
4222
4223                 if ( $this->getNamespace() != NS_FILE ) {
4224                         # Remove the upload restriction for non-file titles
4225                         $types = array_diff( $types, array( 'upload' ) );
4226                 }
4227
4228                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
4229
4230                 wfDebug( __METHOD__ . ': applicable restriction types for ' .
4231                         $this->getPrefixedText() . ' are ' . implode( ',', $types ) . "\n" );
4232
4233                 return $types;
4234         }
4235         /**
4236          * Get a filtered list of all restriction types supported by this wiki.
4237          * @param bool $exists True to get all restriction types that apply to
4238          * titles that do exist, False for all restriction types that apply to
4239          * titles that do not exist
4240          * @return array
4241          */
4242         public static function getFilteredRestrictionTypes( $exists = true ) {
4243                 global $wgRestrictionTypes;
4244                 $types = $wgRestrictionTypes;
4245                 if ( $exists ) {
4246                         # Remove the create restriction for existing titles
4247                         $types = array_diff( $types, array( 'create' ) );
4248                 } else {
4249                         # Only the create and upload restrictions apply to non-existing titles
4250                         $types = array_intersect( $types, array( 'create', 'upload' ) );
4251                 }
4252                 return $types;
4253         }
4254
4255         /**
4256          * Returns the raw sort key to be used for categories, with the specified
4257          * prefix.  This will be fed to Collation::getSortKey() to get a
4258          * binary sortkey that can be used for actual sorting.
4259          *
4260          * @param $prefix string The prefix to be used, specified using
4261          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4262          *   prefix.
4263          * @return string
4264          */
4265         public function getCategorySortkey( $prefix = '' ) {
4266                 $unprefixed = $this->getText();
4267
4268                 // Anything that uses this hook should only depend
4269                 // on the Title object passed in, and should probably
4270                 // tell the users to run updateCollations.php --force
4271                 // in order to re-sort existing category relations.
4272                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4273                 if ( $prefix !== '' ) {
4274                         # Separate with a line feed, so the unprefixed part is only used as
4275                         # a tiebreaker when two pages have the exact same prefix.
4276                         # In UCA, tab is the only character that can sort above LF
4277                         # so we strip both of them from the original prefix.
4278                         $prefix = strtr( $prefix, "\n\t", '  ' );
4279                         return "$prefix\n$unprefixed";
4280                 }
4281                 return $unprefixed;
4282         }
4283
4284         /**
4285          * Get the language in which the content of this page is written.
4286          * Defaults to $wgContLang, but in certain cases it can be e.g.
4287          * $wgLang (such as special pages, which are in the user language).
4288          *
4289          * @return object Language
4290          */
4291         public function getPageLanguage() {
4292                 global $wgLang;
4293                 if ( $this->getNamespace() == NS_SPECIAL ) {
4294                         // special pages are in the user language
4295                         return $wgLang;
4296                 } elseif ( $this->isRedirect() ) {
4297                         // the arrow on a redirect page is aligned according to the user language
4298                         return $wgLang;
4299                 } elseif ( $this->isCssOrJsPage() ) {
4300                         // css/js should always be LTR and is, in fact, English
4301                         return wfGetLangObj( 'en' );
4302                 } elseif ( $this->getNamespace() == NS_MEDIAWIKI ) {
4303                         // Parse mediawiki messages with correct target language
4304                         list( /* $unused */, $lang ) = MessageCache::singleton()->figureMessage( $this->getText() );
4305                         return wfGetLangObj( $lang );
4306                 }
4307                 global $wgContLang;
4308                 // If nothing special, it should be in the wiki content language
4309                 $pageLang = $wgContLang;
4310                 // Hook at the end because we don't want to override the above stuff
4311                 wfRunHooks( 'PageContentLanguage', array( $this, &$pageLang, $wgLang ) );
4312                 return wfGetLangObj( $pageLang );
4313         }
4314 }
4315
4316 /**
4317  * A BadTitle is generated in MediaWiki::parseTitle() if the title is invalid; the
4318  * software uses this to display an error page.  Internally it's basically a Title
4319  * for an empty special page
4320  */
4321 class BadTitle extends Title {
4322         public function __construct(){
4323                 $this->mTextform = '';
4324                 $this->mUrlform = '';
4325                 $this->mDbkeyform = '';
4326                 $this->mNamespace = NS_SPECIAL; // Stops talk page link, etc, being shown
4327         }
4328
4329         public function exists(){
4330                 return false;
4331         }
4332
4333         public function getPrefixedText(){
4334                 return '';
4335         }
4336
4337         public function getText(){
4338                 return '';
4339         }
4340
4341         public function getPrefixedURL(){
4342                 return '';
4343         }
4344
4345         public function getPrefixedDBKey(){
4346                 return '';
4347         }
4348 }