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          * @name Private member variables
  52          * Please use the accessor functions instead.
  53          * @private
  54          */
  55         // @{
  56
  57         var $mTextform = '';              // /< Text form (spaces not underscores) of the main part
  58         var $mUrlform = '';               // /< URL-encoded form of the main part
  59         var $mDbkeyform = '';             // /< Main part with underscores
  60         var $mUserCaseDBKey;              // /< DB key with the initial letter in the case specified by the user
  61         var $mNamespace = NS_MAIN;        // /< Namespace index, i.e. one of the NS_xxxx constants
  62         var $mInterwiki = '';             // /< Interwiki prefix (or null string)
  63         var $mFragment;                   // /< Title fragment (i.e. the bit after the #)
  64         var $mArticleID = -1;             // /< Article ID, fetched from the link cache on demand
  65         var $mLatestID = false;           // /< ID of most recent revision
  66         private $mEstimateRevisions;      // /< Estimated number of revisions; null of not loaded
  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|bool database row
 264          */
 265         public function loadFromRow( $row ) {
 266                 if ( $row ) { // page found
 267                         if ( isset( $row->page_id ) )
 268                                 $this->mArticleID = (int)$row->page_id;
 269                         if ( isset( $row->page_len ) )
 270                                 $this->mLength = (int)$row->page_len;
 271                         if ( isset( $row->page_is_redirect ) )
 272                                 $this->mRedirect = (bool)$row->page_is_redirect;
 273                         if ( isset( $row->page_latest ) )
 274                                 $this->mLatestID = (int)$row->page_latest; # FIXME: whene3ver page_latest is updated, also update page_content_model
 275             if ( isset( $row->page_content_model ) )
 276                 $this->mContentModelName = $row->page_content_model;
 277             else
 278                 $this->mContentModelName = null; # initialized lazily in getContentModelName()
 279                 } else { // page not found
 280                         $this->mArticleID = 0;
 281                         $this->mLength = 0;
 282                         $this->mRedirect = false;
 283                         $this->mLatestID = 0;
 284             $this->mContentModelName = null; # initialized lazily in getContentModelName()
 285                 }
 286         }
 287
 288         /**
 289          * Create a new Title from a namespace index and a DB key.
 290          * It's assumed that $ns and $title are *valid*, for instance when
 291          * they came directly from the database or a special page name.
 292          * For convenience, spaces are converted to underscores so that
 293          * eg user_text fields can be used directly.
 294          *
 295          * @param $ns Int the namespace of the article
 296          * @param $title String the unprefixed database key form
 297          * @param $fragment String the link fragment (after the "#")
 298          * @param $interwiki String the interwiki prefix
 299          * @return Title the new object
 300          */
 301         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 302                 $t = new Title();
 303                 $t->mInterwiki = $interwiki;
 304                 $t->mFragment = $fragment;
 305                 $t->mNamespace = $ns = intval( $ns );
 306                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 307                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 308                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 309                 $t->mTextform = str_replace( '_', ' ', $title );
 310         $t->mContentModelName = null; # initialized lazily in getContentModelName()
 311                 return $t;
 312         }
 313
 314         /**
 315          * Create a new Title from a namespace index and a DB key.
 316          * The parameters will be checked for validity, which is a bit slower
 317          * than makeTitle() but safer for user-provided data.
 318          *
 319          * @param $ns Int the namespace of the article
 320          * @param $title String database key form
 321          * @param $fragment String the link fragment (after the "#")
 322          * @param $interwiki String interwiki prefix
 323          * @return Title the new object, or NULL on an error
 324          */
 325         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 326                 if ( !MWNamespace::exists( $ns ) ) {
 327                         return null;
 328                 }
 329
 330                 $t = new Title();
 331                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 332                 if ( $t->secureAndSplit() ) {
 333                         return $t;
 334                 } else {
 335                         return null;
 336                 }
 337         }
 338
 339         /**
 340          * Create a new Title for the Main Page
 341          *
 342          * @return Title the new object
 343          */
 344         public static function newMainPage() {
 345                 $title = Title::newFromText( wfMsgForContent( 'mainpage' ) );
 346                 // Don't give fatal errors if the message is broken
 347                 if ( !$title ) {
 348                         $title = Title::newFromText( 'Main Page' );
 349                 }
 350                 return $title;
 351         }
 352
 353         /**
 354          * Extract a redirect destination from a string and return the
 355          * Title, or null if the text doesn't contain a valid redirect
 356          * This will only return the very next target, useful for
 357          * the redirect table and other checks that don't need full recursion
 358          *
 359          * @param $text String: Text with possible redirect
 360          * @return Title: The corresponding Title
 361          */
 362         public static function newFromRedirect( $text ) {
 363                 return self::newFromRedirectInternal( $text );
 364         }
 365
 366         /**
 367          * Extract a redirect destination from a string and return the
 368          * Title, or null if the text doesn't contain a valid redirect
 369          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 370          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 371          *
 372          * @param $text String Text with possible redirect
 373          * @return Title
 374          */
 375         public static function newFromRedirectRecurse( $text ) {
 376                 $titles = self::newFromRedirectArray( $text );
 377                 return $titles ? array_pop( $titles ) : null;
 378         }
 379
 380         /**
 381          * Extract a redirect destination from a string and return an
 382          * array of Titles, or null if the text doesn't contain a valid redirect
 383          * The last element in the array is the final destination after all redirects
 384          * have been resolved (up to $wgMaxRedirects times)
 385          *
 386          * @param $text String Text with possible redirect
 387          * @return Array of Titles, with the destination last
 388          */
 389         public static function newFromRedirectArray( $text ) {
 390                 global $wgMaxRedirects;
 391                 $title = self::newFromRedirectInternal( $text );
 392                 if ( is_null( $title ) ) {
 393                         return null;
 394                 }
 395                 // recursive check to follow double redirects
 396                 $recurse = $wgMaxRedirects;
 397                 $titles = array( $title );
 398                 while ( --$recurse > 0 ) {
 399                         if ( $title->isRedirect() ) {
 400                                 $page = WikiPage::factory( $title );
 401                                 $newtitle = $page->getRedirectTarget();
 402                         } else {
 403                                 break;
 404                         }
 405                         // Redirects to some special pages are not permitted
 406                         if ( $newtitle instanceOf Title && $newtitle->isValidRedirectTarget() ) {
 407                                 // the new title passes the checks, so make that our current title so that further recursion can be checked
 408                                 $title = $newtitle;
 409                                 $titles[] = $newtitle;
 410                         } else {
 411                                 break;
 412                         }
 413                 }
 414                 return $titles;
 415         }
 416
 417         /**
 418          * Really extract the redirect destination
 419          * Do not call this function directly, use one of the newFromRedirect* functions above
 420          *
 421          * @param $text String Text with possible redirect
 422          * @return Title
 423          */
 424         protected static function newFromRedirectInternal( $text ) {
 425                 global $wgMaxRedirects;
 426                 if ( $wgMaxRedirects < 1 ) {
 427                         //redirects are disabled, so quit early
 428                         return null;
 429                 }
 430                 $redir = MagicWord::get( 'redirect' );
 431                 $text = trim( $text );
 432                 if ( $redir->matchStartAndRemove( $text ) ) {
 433                         // Extract the first link and see if it's usable
 434                         // Ensure that it really does come directly after #REDIRECT
 435                         // Some older redirects included a colon, so don't freak about that!
 436                         $m = array();
 437                         if ( preg_match( '!^\s*:?\s*\[{2}(.*?)(?:\|.*?)?\]{2}!', $text, $m ) ) {
 438                                 // Strip preceding colon used to "escape" categories, etc.
 439                                 // and URL-decode links
 440                                 if ( strpos( $m[1], '%' ) !== false ) {
 441                                         // Match behavior of inline link parsing here;
 442                                         $m[1] = rawurldecode( ltrim( $m[1], ':' ) );
 443                                 }
 444                                 $title = Title::newFromText( $m[1] );
 445                                 // If the title is a redirect to bad special pages or is invalid, return null
 446                                 if ( !$title instanceof Title || !$title->isValidRedirectTarget() ) {
 447                                         return null;
 448                                 }
 449                                 return $title;
 450                         }
 451                 }
 452                 return null;
 453         }
 454
 455         /**
 456          * Get the prefixed DB key associated with an ID
 457          *
 458          * @param $id Int the page_id of the article
 459          * @return Title an object representing the article, or NULL if no such article was found
 460          */
 461         public static function nameOf( $id ) {
 462                 $dbr = wfGetDB( DB_SLAVE );
 463
 464                 $s = $dbr->selectRow(
 465                         'page',
 466                         array( 'page_namespace', 'page_title' ),
 467                         array( 'page_id' => $id ),
 468                         __METHOD__
 469                 );
 470                 if ( $s === false ) {
 471                         return null;
 472                 }
 473
 474                 $n = self::makeName( $s->page_namespace, $s->page_title );
 475                 return $n;
 476         }
 477
 478         /**
 479          * Get a regex character class describing the legal characters in a link
 480          *
 481          * @return String the list of characters, not delimited
 482          */
 483         public static function legalChars() {
 484                 global $wgLegalTitleChars;
 485                 return $wgLegalTitleChars;
 486         }
 487
 488         /**
 489          * Returns a simple regex that will match on characters and sequences invalid in titles.
 490          * Note that this doesn't pick up many things that could be wrong with titles, but that
 491          * replacing this regex with something valid will make many titles valid.
 492          *
 493          * @return String regex string
 494          */
 495         static function getTitleInvalidRegex() {
 496                 static $rxTc = false;
 497                 if ( !$rxTc ) {
 498                         # Matching titles will be held as illegal.
 499                         $rxTc = '/' .
 500                                 # Any character not allowed is forbidden...
 501                                 '[^' . self::legalChars() . ']' .
 502                                 # URL percent encoding sequences interfere with the ability
 503                                 # to round-trip titles -- you can't link to them consistently.
 504                                 '|%[0-9A-Fa-f]{2}' .
 505                                 # XML/HTML character references produce similar issues.
 506                                 '|&[A-Za-z0-9\x80-\xff]+;' .
 507                                 '|&#[0-9]+;' .
 508                                 '|&#x[0-9A-Fa-f]+;' .
 509                                 '/S';
 510                 }
 511
 512                 return $rxTc;
 513         }
 514
 515         /**
 516          * Get a string representation of a title suitable for
 517          * including in a search index
 518          *
 519          * @param $ns Int a namespace index
 520          * @param $title String text-form main part
 521          * @return String a stripped-down title string ready for the search index
 522          */
 523         public static function indexTitle( $ns, $title ) {
 524                 global $wgContLang;
 525
 526                 $lc = SearchEngine::legalSearchChars() . '&#;';
 527                 $t = $wgContLang->normalizeForSearch( $title );
 528                 $t = preg_replace( "/[^{$lc}]+/", ' ', $t );
 529                 $t = $wgContLang->lc( $t );
 530
 531                 # Handle 's, s'
 532                 $t = preg_replace( "/([{$lc}]+)'s( |$)/", "\\1 \\1's ", $t );
 533                 $t = preg_replace( "/([{$lc}]+)s'( |$)/", "\\1s ", $t );
 534
 535                 $t = preg_replace( "/\\s+/", ' ', $t );
 536
 537                 if ( $ns == NS_FILE ) {
 538                         $t = preg_replace( "/ (png|gif|jpg|jpeg|ogg)$/", "", $t );
 539                 }
 540                 return trim( $t );
 541         }
 542
 543         /**
 544          * Make a prefixed DB key from a DB key and a namespace index
 545          *
 546          * @param $ns Int numerical representation of the namespace
 547          * @param $title String the DB key form the title
 548          * @param $fragment String The link fragment (after the "#")
 549          * @param $interwiki String The interwiki prefix
 550          * @return String the prefixed form of the title
 551          */
 552         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 553                 global $wgContLang;
 554
 555                 $namespace = $wgContLang->getNsText( $ns );
 556                 $name = $namespace == '' ? $title : "$namespace:$title";
 557                 if ( strval( $interwiki ) != '' ) {
 558                         $name = "$interwiki:$name";
 559                 }
 560                 if ( strval( $fragment ) != '' ) {
 561                         $name .= '#' . $fragment;
 562                 }
 563                 return $name;
 564         }
 565
 566         /**
 567          * Escape a text fragment, say from a link, for a URL
 568          *
 569          * @param $fragment string containing a URL or link fragment (after the "#")
 570          * @return String: escaped string
 571          */
 572         static function escapeFragmentForURL( $fragment ) {
 573                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 574                 # fragments appear not to work in IE (at least up to 7) or in at least
 575                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 576                 # to care if they aren't encoded.
 577                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 578         }
 579
 580         /**
 581          * Callback for usort() to do title sorts by (namespace, title)
 582          *
 583          * @param $a Title
 584          * @param $b Title
 585          *
 586          * @return Integer: result of string comparison, or namespace comparison
 587          */
 588         public static function compare( $a, $b ) {
 589                 if ( $a->getNamespace() == $b->getNamespace() ) {
 590                         return strcmp( $a->getText(), $b->getText() );
 591                 } else {
 592                         return $a->getNamespace() - $b->getNamespace();
 593                 }
 594         }
 595
 596         /**
 597          * Determine whether the object refers to a page within
 598          * this project.
 599          *
 600          * @return Bool TRUE if this is an in-project interwiki link or a wikilink, FALSE otherwise
 601          */
 602         public function isLocal() {
 603                 if ( $this->mInterwiki != '' ) {
 604                         return Interwiki::fetch( $this->mInterwiki )->isLocal();
 605                 } else {
 606                         return true;
 607                 }
 608         }
 609
 610         /**
 611          * Is this Title interwiki?
 612          *
 613          * @return Bool
 614          */
 615         public function isExternal() {
 616                 return ( $this->mInterwiki != '' );
 617         }
 618
 619         /**
 620          * Get the interwiki prefix (or null string)
 621          *
 622          * @return String Interwiki prefix
 623          */
 624         public function getInterwiki() {
 625                 return $this->mInterwiki;
 626         }
 627
 628         /**
 629          * Determine whether the object refers to a page within
 630          * this project and is transcludable.
 631          *
 632          * @return Bool TRUE if this is transcludable
 633          */
 634         public function isTrans() {
 635                 if ( $this->mInterwiki == '' ) {
 636                         return false;
 637                 }
 638
 639                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 640         }
 641
 642         /**
 643          * Returns the DB name of the distant wiki which owns the object.
 644          *
 645          * @return String the DB name
 646          */
 647         public function getTransWikiID() {
 648                 if ( $this->mInterwiki == '' ) {
 649                         return false;
 650                 }
 651
 652                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 653         }
 654
 655         /**
 656          * Get the text form (spaces not underscores) of the main part
 657          *
 658          * @return String Main part of the title
 659          */
 660         public function getText() {
 661                 return $this->mTextform;
 662         }
 663
 664         /**
 665          * Get the URL-encoded form of the main part
 666          *
 667          * @return String Main part of the title, URL-encoded
 668          */
 669         public function getPartialURL() {
 670                 return $this->mUrlform;
 671         }
 672
 673         /**
 674          * Get the main part with underscores
 675          *
 676          * @return String: Main part of the title, with underscores
 677          */
 678         public function getDBkey() {
 679                 return $this->mDbkeyform;
 680         }
 681
 682         /**
 683          * Get the DB key with the initial letter case as specified by the user
 684          *
 685          * @return String DB key
 686          */
 687         function getUserCaseDBKey() {
 688                 return $this->mUserCaseDBKey;
 689         }
 690
 691         /**
 692          * Get the namespace index, i.e. one of the NS_xxxx constants.
 693          *
 694          * @return Integer: Namespace index
 695          */
 696         public function getNamespace() {
 697                 return $this->mNamespace;
 698         }
 699
 700     /**
 701      * Get the page's content model name
 702      *
 703      * @return Integer: Namespace index
 704      */
 705     public function getContentModelName() {
 706         if ( empty( $this->mContentModelName ) ) {
 707             $this->mContentModelName = ContentHandler::getDefaultModelFor( $this );
 708         }
 709
 710         return $this->mContentModelName;
 711     }
 712
 713     /**
 714      * Conveniance method for checking a title's content model name
 715      *
 716      * @param $name
 717      * @return true if $this->getContentModelName() == $name
 718      */
 719     public function hasContentModel( $name ) {
 720         return $this->getContentModelName() == $name;
 721     }
 722
 723         /**
 724          * Get the namespace text
 725          *
 726          * @return String: Namespace text
 727          */
 728         public function getNsText() {
 729                 global $wgContLang;
 730
 731                 if ( $this->mInterwiki != '' ) {
 732                         // This probably shouldn't even happen. ohh man, oh yuck.
 733                         // But for interwiki transclusion it sometimes does.
 734                         // Shit. Shit shit shit.
 735                         //
 736                         // Use the canonical namespaces if possible to try to
 737                         // resolve a foreign namespace.
 738                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 739                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 740                         }
 741                 }
 742
 743                 if ( $wgContLang->needsGenderDistinction() &&
 744                                 MWNamespace::hasGenderDistinction( $this->mNamespace ) ) {
 745                         $gender = GenderCache::singleton()->getGenderOf( $this->getText(), __METHOD__ );
 746                         return $wgContLang->getGenderNsText( $this->mNamespace, $gender );
 747                 }
 748
 749                 return $wgContLang->getNsText( $this->mNamespace );
 750         }
 751
 752         /**
 753          * Get the namespace text of the subject (rather than talk) page
 754          *
 755          * @return String Namespace text
 756          */
 757         public function getSubjectNsText() {
 758                 global $wgContLang;
 759                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 760         }
 761
 762         /**
 763          * Get the namespace text of the talk page
 764          *
 765          * @return String Namespace text
 766          */
 767         public function getTalkNsText() {
 768                 global $wgContLang;
 769                 return( $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) ) );
 770         }
 771
 772         /**
 773          * Could this title have a corresponding talk page?
 774          *
 775          * @return Bool TRUE or FALSE
 776          */
 777         public function canTalk() {
 778                 return( MWNamespace::canTalk( $this->mNamespace ) );
 779         }
 780
 781         /**
 782          * Is this in a namespace that allows actual pages?
 783          *
 784          * @return Bool
 785          * @internal note -- uses hardcoded namespace index instead of constants
 786          */
 787         public function canExist() {
 788                 return $this->mNamespace >= NS_MAIN;
 789         }
 790
 791         /**
 792          * Can this title be added to a user's watchlist?
 793          *
 794          * @return Bool TRUE or FALSE
 795          */
 796         public function isWatchable() {
 797                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
 798         }
 799
 800         /**
 801          * Returns true if this is a special page.
 802          *
 803          * @return boolean
 804          */
 805         public function isSpecialPage() {
 806                 return $this->getNamespace() == NS_SPECIAL;
 807         }
 808
 809         /**
 810          * Returns true if this title resolves to the named special page
 811          *
 812          * @param $name String The special page name
 813          * @return boolean
 814          */
 815         public function isSpecial( $name ) {
 816                 if ( $this->isSpecialPage() ) {
 817                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
 818                         if ( $name == $thisName ) {
 819                                 return true;
 820                         }
 821                 }
 822                 return false;
 823         }
 824
 825         /**
 826          * If the Title refers to a special page alias which is not the local default, resolve
 827          * the alias, and localise the name as necessary.  Otherwise, return $this
 828          *
 829          * @return Title
 830          */
 831         public function fixSpecialName() {
 832                 if ( $this->isSpecialPage() ) {
 833                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
 834                         if ( $canonicalName ) {
 835                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
 836                                 if ( $localName != $this->mDbkeyform ) {
 837                                         return Title::makeTitle( NS_SPECIAL, $localName );
 838                                 }
 839                         }
 840                 }
 841                 return $this;
 842         }
 843
 844         /**
 845          * Returns true if the title is inside the specified namespace.
 846          *
 847          * Please make use of this instead of comparing to getNamespace()
 848          * This function is much more resistant to changes we may make
 849          * to namespaces than code that makes direct comparisons.
 850          * @param $ns int The namespace
 851          * @return bool
 852          * @since 1.19
 853          */
 854         public function inNamespace( $ns ) {
 855                 return MWNamespace::equals( $this->getNamespace(), $ns );
 856         }
 857
 858         /**
 859          * Returns true if the title is inside one of the specified namespaces.
 860          *
 861          * @param ...$namespaces The namespaces to check for
 862          * @return bool
 863          * @since 1.19
 864          */
 865         public function inNamespaces( /* ... */ ) {
 866                 $namespaces = func_get_args();
 867                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
 868                         $namespaces = $namespaces[0];
 869                 }
 870
 871                 foreach ( $namespaces as $ns ) {
 872                         if ( $this->inNamespace( $ns ) ) {
 873                                 return true;
 874                         }
 875                 }
 876
 877                 return false;
 878         }
 879
 880         /**
 881          * Returns true if the title has the same subject namespace as the
 882          * namespace specified.
 883          * For example this method will take NS_USER and return true if namespace
 884          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
 885          * as their subject namespace.
 886          *
 887          * This is MUCH simpler than individually testing for equivilance
 888          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
 889          * @since 1.19
 890          * @return bool
 891          */
 892         public function hasSubjectNamespace( $ns ) {
 893                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
 894         }
 895
 896         /**
 897          * Is this Title in a namespace which contains content?
 898          * In other words, is this a content page, for the purposes of calculating
 899          * statistics, etc?
 900          *
 901          * @return Boolean
 902          */
 903         public function isContentPage() {
 904                 return MWNamespace::isContent( $this->getNamespace() );
 905         }
 906
 907         /**
 908          * Would anybody with sufficient privileges be able to move this page?
 909          * Some pages just aren't movable.
 910          *
 911          * @return Bool TRUE or FALSE
 912          */
 913         public function isMovable() {
 914                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->getInterwiki() != '' ) {
 915                         // Interwiki title or immovable namespace. Hooks don't get to override here
 916                         return false;
 917                 }
 918
 919                 $result = true;
 920                 wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
 921                 return $result;
 922         }
 923
 924         /**
 925          * Is this the mainpage?
 926          * @note Title::newFromText seams to be sufficiently optimized by the title
 927          * cache that we don't need to over-optimize by doing direct comparisons and
 928          * acidentally creating new bugs where $title->equals( Title::newFromText() )
 929          * ends up reporting something differently than $title->isMainPage();
 930          *
 931          * @since 1.18
 932          * @return Bool
 933          */
 934         public function isMainPage() {
 935                 return $this->equals( Title::newMainPage() );
 936         }
 937
 938         /**
 939          * Is this a subpage?
 940          *
 941          * @return Bool
 942          */
 943         public function isSubpage() {
 944                 return MWNamespace::hasSubpages( $this->mNamespace )
 945                         ? strpos( $this->getText(), '/' ) !== false
 946                         : false;
 947         }
 948
 949         /**
 950          * Is this a conversion table for the LanguageConverter?
 951          *
 952          * @return Bool
 953          */
 954         public function isConversionTable() {
 955                 return $this->getNamespace() == NS_MEDIAWIKI &&
 956                         strpos( $this->getText(), 'Conversiontable' ) !== false;
 957         }
 958
 959         /**
 960          * Does that page contain wikitext, or it is JS, CSS or whatever?
 961          *
 962          * @return Bool
 963          */
 964         public function isWikitextPage() {
 965                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
 966         }
 967
 968         /**
 969          * Could this page contain custom CSS or JavaScript for the global UI.
 970      * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
 971      * or CONTENT_MODEL_JAVASCRIPT.
 972      *
 973      * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage() for that!
 974      *
 975      * Note that this method should not return true for pages that contain and show "inactive" CSS or JS.
 976          *
 977          * @return Bool
 978          */
 979         public function isCssOrJsPage() {
 980         $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
 981             && ( $this->hasContentModel( CONTENT_MODEL_CSS )
 982                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
 983
 984         #NOTE: this hook is also called in ContentHandler::getDefaultModel. It's called here again to make sure
 985         #      hook funktions can force this method to return true even outside the mediawiki namespace.
 986
 987         wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ) );
 988
 989         return $isCssOrJsPage;
 990         }
 991
 992         /**
 993          * Is this a .css or .js subpage of a user page?
 994          * @return Bool
 995          */
 996         public function isCssJsSubpage() {
 997                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
 998                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
 999                     || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1000         }
1001
1002         /**
1003          * Trim down a .css or .js subpage title to get the corresponding skin name
1004          *
1005          * @return string containing skin name from .css or .js subpage title
1006          */
1007         public function getSkinFromCssJsSubpage() {
1008                 $subpage = explode( '/', $this->mTextform );
1009                 $subpage = $subpage[ count( $subpage ) - 1 ];
1010                 $lastdot = strrpos( $subpage, '.' );
1011                 if ( $lastdot === false )
1012                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1013                 return substr( $subpage, 0, $lastdot );
1014         }
1015
1016         /**
1017          * Is this a .css subpage of a user page?
1018          *
1019          * @return Bool
1020          */
1021         public function isCssSubpage() {
1022         return ( NS_USER == $this->mNamespace && $this->isSubpage()
1023             && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1024         }
1025
1026         /**
1027          * Is this a .js subpage of a user page?
1028          *
1029          * @return Bool
1030          */
1031         public function isJsSubpage() {
1032         return ( NS_USER == $this->mNamespace && $this->isSubpage()
1033             && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1034         }
1035
1036         /**
1037          * Is this a talk page of some sort?
1038          *
1039          * @return Bool
1040          */
1041         public function isTalkPage() {
1042                 return MWNamespace::isTalk( $this->getNamespace() );
1043         }
1044
1045         /**
1046          * Get a Title object associated with the talk page of this article
1047          *
1048          * @return Title the object for the talk page
1049          */
1050         public function getTalkPage() {
1051                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1052         }
1053
1054         /**
1055          * Get a title object associated with the subject page of this
1056          * talk page
1057          *
1058          * @return Title the object for the subject page
1059          */
1060         public function getSubjectPage() {
1061                 // Is this the same title?
1062                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1063                 if ( $this->getNamespace() == $subjectNS ) {
1064                         return $this;
1065                 }
1066                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1067         }
1068
1069         /**
1070          * Get the default namespace index, for when there is no namespace
1071          *
1072          * @return Int Default namespace index
1073          */
1074         public function getDefaultNamespace() {
1075                 return $this->mDefaultNamespace;
1076         }
1077
1078         /**
1079          * Get title for search index
1080          *
1081          * @return String a stripped-down title string ready for the
1082          *  search index
1083          */
1084         public function getIndexTitle() {
1085                 return Title::indexTitle( $this->mNamespace, $this->mTextform );
1086         }
1087
1088         /**
1089          * Get the Title fragment (i.e.\ the bit after the #) in text form
1090          *
1091          * @return String Title fragment
1092          */
1093         public function getFragment() {
1094                 return $this->mFragment;
1095         }
1096
1097         /**
1098          * Get the fragment in URL form, including the "#" character if there is one
1099          * @return String Fragment in URL form
1100          */
1101         public function getFragmentForURL() {
1102                 if ( $this->mFragment == '' ) {
1103                         return '';
1104                 } else {
1105                         return '#' . Title::escapeFragmentForURL( $this->mFragment );
1106                 }
1107         }
1108
1109         /**
1110          * Set the fragment for this title. Removes the first character from the
1111          * specified fragment before setting, so it assumes you're passing it with
1112          * an initial "#".
1113          *
1114          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1115          * Still in active use privately.
1116          *
1117          * @param $fragment String text
1118          */
1119         public function setFragment( $fragment ) {
1120                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1121         }
1122
1123         /**
1124          * Prefix some arbitrary text with the namespace or interwiki prefix
1125          * of this object
1126          *
1127          * @param $name String the text
1128          * @return String the prefixed text
1129          * @private
1130          */
1131         private function prefix( $name ) {
1132                 $p = '';
1133                 if ( $this->mInterwiki != '' ) {
1134                         $p = $this->mInterwiki . ':';
1135                 }
1136
1137                 if ( 0 != $this->mNamespace ) {
1138                         $p .= $this->getNsText() . ':';
1139                 }
1140                 return $p . $name;
1141         }
1142
1143         /**
1144          * Get the prefixed database key form
1145          *
1146          * @return String the prefixed title, with underscores and
1147          *  any interwiki and namespace prefixes
1148          */
1149         public function getPrefixedDBkey() {
1150                 $s = $this->prefix( $this->mDbkeyform );
1151                 $s = str_replace( ' ', '_', $s );
1152                 return $s;
1153         }
1154
1155         /**
1156          * Get the prefixed title with spaces.
1157          * This is the form usually used for display
1158          *
1159          * @return String the prefixed title, with spaces
1160          */
1161         public function getPrefixedText() {
1162                 // @todo FIXME: Bad usage of empty() ?
1163                 if ( empty( $this->mPrefixedText ) ) {
1164                         $s = $this->prefix( $this->mTextform );
1165                         $s = str_replace( '_', ' ', $s );
1166                         $this->mPrefixedText = $s;
1167                 }
1168                 return $this->mPrefixedText;
1169         }
1170
1171         /**
1172          * Return a string representation of this title
1173          *
1174          * @return String representation of this title
1175          */
1176         public function __toString() {
1177                 return $this->getPrefixedText();
1178         }
1179
1180         /**
1181          * Get the prefixed title with spaces, plus any fragment
1182          * (part beginning with '#')
1183          *
1184          * @return String the prefixed title, with spaces and the fragment, including '#'
1185          */
1186         public function getFullText() {
1187                 $text = $this->getPrefixedText();
1188                 if ( $this->mFragment != '' ) {
1189                         $text .= '#' . $this->mFragment;
1190                 }
1191                 return $text;
1192         }
1193
1194         /**
1195          * Get the base page name, i.e. the leftmost part before any slashes
1196          *
1197          * @return String Base name
1198          */
1199         public function getBaseText() {
1200                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1201                         return $this->getText();
1202                 }
1203
1204                 $parts = explode( '/', $this->getText() );
1205                 # Don't discard the real title if there's no subpage involved
1206                 if ( count( $parts ) > 1 ) {
1207                         unset( $parts[count( $parts ) - 1] );
1208                 }
1209                 return implode( '/', $parts );
1210         }
1211
1212         /**
1213          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1214          *
1215          * @return String Subpage name
1216          */
1217         public function getSubpageText() {
1218                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1219                         return( $this->mTextform );
1220                 }
1221                 $parts = explode( '/', $this->mTextform );
1222                 return( $parts[count( $parts ) - 1] );
1223         }
1224
1225         /**
1226          * Get the HTML-escaped displayable text form.
1227          * Used for the title field in <a> tags.
1228          *
1229          * @return String the text, including any prefixes
1230          */
1231         public function getEscapedText() {
1232                 wfDeprecated( __METHOD__, '1.19' );
1233                 return htmlspecialchars( $this->getPrefixedText() );
1234         }
1235
1236         /**
1237          * Get a URL-encoded form of the subpage text
1238          *
1239          * @return String URL-encoded subpage name
1240          */
1241         public function getSubpageUrlForm() {
1242                 $text = $this->getSubpageText();
1243                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1244                 return( $text );
1245         }
1246
1247         /**
1248          * Get a URL-encoded title (not an actual URL) including interwiki
1249          *
1250          * @return String the URL-encoded form
1251          */
1252         public function getPrefixedURL() {
1253                 $s = $this->prefix( $this->mDbkeyform );
1254                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1255                 return $s;
1256         }
1257
1258         /**
1259          * Helper to fix up the get{Local,Full,Link,Canonical}URL args
1260          * get{Canonical,Full,Link,Local}URL methods accepted an optional
1261          * second argument named variant. This was deprecated in favor
1262          * of passing an array of option with a "variant" key
1263          * Once $query2 is removed for good, this helper can be dropped
1264          * andthe wfArrayToCGI moved to getLocalURL();
1265          *
1266          * @since 1.19 (r105919)
1267          * @return String
1268          */
1269         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1270                 if( $query2 !== false ) {
1271                         wfDeprecated( "Title::get{Canonical,Full,Link,Local} method called with a second parameter is deprecated. Add your parameter to an array passed as the first parameter.", "1.19" );
1272                 }
1273                 if ( is_array( $query ) ) {
1274                         $query = wfArrayToCGI( $query );
1275                 }
1276                 if ( $query2 ) {
1277                         if ( is_string( $query2 ) ) {
1278                                 // $query2 is a string, we will consider this to be
1279                                 // a deprecated $variant argument and add it to the query
1280                                 $query2 = wfArrayToCGI( array( 'variant' => $query2 ) );
1281                         } else {
1282                                 $query2 = wfArrayToCGI( $query2 );
1283                         }
1284                         // If we have $query content add a & to it first
1285                         if ( $query ) {
1286                                 $query .= '&';
1287                         }
1288                         // Now append the queries together
1289                         $query .= $query2;
1290                 }
1291                 return $query;
1292         }
1293
1294         /**
1295          * Get a real URL referring to this title, with interwiki link and
1296          * fragment
1297          *
1298          * See getLocalURL for the arguments.
1299          *
1300          * @see self::getLocalURL
1301          * @return String the URL
1302          */
1303         public function getFullURL( $query = '', $query2 = false ) {
1304                 $query = self::fixUrlQueryArgs( $query, $query2 );
1305
1306                 # Hand off all the decisions on urls to getLocalURL
1307                 $url = $this->getLocalURL( $query );
1308
1309                 # Expand the url to make it a full url. Note that getLocalURL has the
1310                 # potential to output full urls for a variety of reasons, so we use
1311                 # wfExpandUrl instead of simply prepending $wgServer
1312                 $url = wfExpandUrl( $url, PROTO_RELATIVE );
1313
1314                 # Finally, add the fragment.
1315                 $url .= $this->getFragmentForURL();
1316
1317                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1318                 return $url;
1319         }
1320
1321         /**
1322          * Get a URL with no fragment or server name.  If this page is generated
1323          * with action=render, $wgServer is prepended.
1324          *
1325
1326          * @param $query string|array an optional query string,
1327          *   not used for interwiki     links. Can be specified as an associative array as well,
1328          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1329          *   Some query patterns will trigger various shorturl path replacements.
1330          * @param $query2 Mixed: An optional secondary query array. This one MUST
1331          *   be an array. If a string is passed it will be interpreted as a deprecated
1332          *   variant argument and urlencoded into a variant= argument.
1333          *   This second query argument will be added to the $query
1334          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1335          *   pair in the first parameter array instead.
1336          *
1337          * @return String the URL
1338          */
1339         public function getLocalURL( $query = '', $query2 = false ) {
1340                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1341
1342                 $query = self::fixUrlQueryArgs( $query, $query2 );
1343
1344                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1345                 if ( $interwiki ) {
1346                         $namespace = $this->getNsText();
1347                         if ( $namespace != '' ) {
1348                                 # Can this actually happen? Interwikis shouldn't be parsed.
1349                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1350                                 $namespace .= ':';
1351                         }
1352                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1353                         $url = wfAppendQuery( $url, $query );
1354                 } else {
1355                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1356                         if ( $query == '' ) {
1357                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1358                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1359                         } else {
1360                                 global $wgVariantArticlePath, $wgActionPaths;
1361                                 $url = false;
1362                                 $matches = array();
1363
1364                                 if ( !empty( $wgActionPaths ) &&
1365                                         preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches ) )
1366                                 {
1367                                         $action = urldecode( $matches[2] );
1368                                         if ( isset( $wgActionPaths[$action] ) ) {
1369                                                 $query = $matches[1];
1370                                                 if ( isset( $matches[4] ) ) {
1371                                                         $query .= $matches[4];
1372                                                 }
1373                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1374                                                 if ( $query != '' ) {
1375                                                         $url = wfAppendQuery( $url, $query );
1376                                                 }
1377                                         }
1378                                 }
1379
1380                                 if ( $url === false &&
1381                                         $wgVariantArticlePath &&
1382                                         $this->getPageLanguage()->hasVariants() &&
1383                                         preg_match( '/^variant=([^&]*)$/', $query, $matches ) )
1384                                 {
1385                                         $variant = urldecode( $matches[1] );
1386                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1387                                                 // Only do the variant replacement if the given variant is a valid
1388                                                 // variant for the page's language.
1389                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1390                                                 $url = str_replace( '$1', $dbkey, $url );
1391                                         }
1392                                 }
1393
1394                                 if ( $url === false ) {
1395                                         if ( $query == '-' ) {
1396                                                 $query = '';
1397                                         }
1398                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1399                                 }
1400                         }
1401
1402                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1403
1404                         // @todo FIXME: This causes breakage in various places when we
1405                         // actually expected a local URL and end up with dupe prefixes.
1406                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1407                                 $url = $wgServer . $url;
1408                         }
1409                 }
1410                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1411                 return $url;
1412         }
1413
1414         /**
1415          * Get a URL that's the simplest URL that will be valid to link, locally,
1416          * to the current Title.  It includes the fragment, but does not include
1417          * the server unless action=render is used (or the link is external).  If
1418          * there's a fragment but the prefixed text is empty, we just return a link
1419          * to the fragment.
1420          *
1421          * The result obviously should not be URL-escaped, but does need to be
1422          * HTML-escaped if it's being output in HTML.
1423          *
1424          * See getLocalURL for the arguments.
1425          *
1426          * @see self::getLocalURL
1427          * @return String the URL
1428          */
1429         public function getLinkURL( $query = '', $query2 = false ) {
1430                 wfProfileIn( __METHOD__ );
1431                 if ( $this->isExternal() ) {
1432                         $ret = $this->getFullURL( $query, $query2 );
1433                 } elseif ( $this->getPrefixedText() === '' && $this->getFragment() !== '' ) {
1434                         $ret = $this->getFragmentForURL();
1435                 } else {
1436                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1437                 }
1438                 wfProfileOut( __METHOD__ );
1439                 return $ret;
1440         }
1441
1442         /**
1443          * Get an HTML-escaped version of the URL form, suitable for
1444          * using in a link, without a server name or fragment
1445          *
1446          * See getLocalURL for the arguments.
1447          *
1448          * @see self::getLocalURL
1449          * @return String the URL
1450          */
1451         public function escapeLocalURL( $query = '', $query2 = false ) {
1452                 wfDeprecated( __METHOD__, '1.19' );
1453                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1454         }
1455
1456         /**
1457          * Get an HTML-escaped version of the URL form, suitable for
1458          * using in a link, including the server name and fragment
1459          *
1460          * See getLocalURL for the arguments.
1461          *
1462          * @see self::getLocalURL
1463          * @return String the URL
1464          */
1465         public function escapeFullURL( $query = '', $query2 = false ) {
1466                 wfDeprecated( __METHOD__, '1.19' );
1467                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1468         }
1469
1470         /**
1471          * Get the URL form for an internal link.
1472          * - Used in various Squid-related code, in case we have a different
1473          * internal hostname for the server from the exposed one.
1474          *
1475          * This uses $wgInternalServer to qualify the path, or $wgServer
1476          * if $wgInternalServer is not set. If the server variable used is
1477          * protocol-relative, the URL will be expanded to http://
1478          *
1479          * See getLocalURL for the arguments.
1480          *
1481          * @see self::getLocalURL
1482          * @return String the URL
1483          */
1484         public function getInternalURL( $query = '', $query2 = false ) {
1485                 global $wgInternalServer, $wgServer;
1486                 $query = self::fixUrlQueryArgs( $query, $query2 );
1487                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1488                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1489                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1490                 return $url;
1491         }
1492
1493         /**
1494          * Get the URL for a canonical link, for use in things like IRC and
1495          * e-mail notifications. Uses $wgCanonicalServer and the
1496          * GetCanonicalURL hook.
1497          *
1498          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1499          *
1500          * See getLocalURL for the arguments.
1501          *
1502          * @see self::getLocalURL
1503          * @return string The URL
1504          * @since 1.18
1505          */
1506         public function getCanonicalURL( $query = '', $query2 = false ) {
1507                 $query = self::fixUrlQueryArgs( $query, $query2 );
1508                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1509                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1510                 return $url;
1511         }
1512
1513         /**
1514          * HTML-escaped version of getCanonicalURL()
1515          *
1516          * See getLocalURL for the arguments.
1517          *
1518          * @see self::getLocalURL
1519          * @since 1.18
1520          * @return string
1521          */
1522         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1523                 wfDeprecated( __METHOD__, '1.19' );
1524                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1525         }
1526
1527         /**
1528          * Get the edit URL for this Title
1529          *
1530          * @return String the URL, or a null string if this is an
1531          *  interwiki link
1532          */
1533         public function getEditURL() {
1534                 if ( $this->mInterwiki != '' ) {
1535                         return '';
1536                 }
1537                 $s = $this->getLocalURL( 'action=edit' );
1538
1539                 return $s;
1540         }
1541
1542         /**
1543          * Is $wgUser watching this page?
1544          *
1545          * @return Bool
1546          */
1547         public function userIsWatching() {
1548                 global $wgUser;
1549
1550                 if ( is_null( $this->mWatched ) ) {
1551                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1552                                 $this->mWatched = false;
1553                         } else {
1554                                 $this->mWatched = $wgUser->isWatched( $this );
1555                         }
1556                 }
1557                 return $this->mWatched;
1558         }
1559
1560         /**
1561          * Can $wgUser read this page?
1562          *
1563          * @deprecated in 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1564          * @return Bool
1565          * @todo fold these checks into userCan()
1566          */
1567         public function userCanRead() {
1568                 wfDeprecated( __METHOD__, '1.19' );
1569                 return $this->userCan( 'read' );
1570         }
1571
1572         /**
1573          * Can $user perform $action on this page?
1574          * This skips potentially expensive cascading permission checks
1575          * as well as avoids expensive error formatting
1576          *
1577          * Suitable for use for nonessential UI controls in common cases, but
1578          * _not_ for functional access control.
1579          *
1580          * May provide false positives, but should never provide a false negative.
1581          *
1582          * @param $action String action that permission needs to be checked for
1583          * @param $user User to check (since 1.19); $wgUser will be used if not
1584          *              provided.
1585          * @return Bool
1586          */
1587         public function quickUserCan( $action, $user = null ) {
1588                 return $this->userCan( $action, $user, false );
1589         }
1590
1591         /**
1592          * Can $user perform $action on this page?
1593          *
1594          * @param $action String action that permission needs to be checked for
1595          * @param $user User to check (since 1.19); $wgUser will be used if not
1596          *   provided.
1597          * @param $doExpensiveQueries Bool Set this to false to avoid doing
1598          *   unnecessary queries.
1599          * @return Bool
1600          */
1601         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1602                 if ( !$user instanceof User ) {
1603                         global $wgUser;
1604                         $user = $wgUser;
1605                 }
1606                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries, true ) );
1607         }
1608
1609         /**
1610          * Can $user perform $action on this page?
1611          *
1612          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1613          *
1614          * @param $action String action that permission needs to be checked for
1615          * @param $user User to check
1616          * @param $doExpensiveQueries Bool Set this to false to avoid doing unnecessary
1617          *   queries by skipping checks for cascading protections and user blocks.
1618          * @param $ignoreErrors Array of Strings Set this to a list of message keys
1619          *   whose corresponding errors may be ignored.
1620          * @return Array of arguments to wfMsg to explain permissions problems.
1621          */
1622         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
1623                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1624
1625                 // Remove the errors being ignored.
1626                 foreach ( $errors as $index => $error ) {
1627                         $error_key = is_array( $error ) ? $error[0] : $error;
1628
1629                         if ( in_array( $error_key, $ignoreErrors ) ) {
1630                                 unset( $errors[$index] );
1631                         }
1632                 }
1633
1634                 return $errors;
1635         }
1636
1637         /**
1638          * Permissions checks that fail most often, and which are easiest to test.
1639          *
1640          * @param $action String the action to check
1641          * @param $user User user to check
1642          * @param $errors Array list of current errors
1643          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1644          * @param $short Boolean short circuit on first error
1645          *
1646          * @return Array list of errors
1647          */
1648         private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1649                 if ( $action == 'create' ) {
1650                         if ( ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1651                                  ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) ) ) {
1652                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1653                         }
1654                 } elseif ( $action == 'move' ) {
1655                         if ( !$user->isAllowed( 'move-rootuserpages' )
1656                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1657                                 // Show user page-specific message only if the user can move other pages
1658                                 $errors[] = array( 'cant-move-user-page' );
1659                         }
1660
1661                         // Check if user is allowed to move files if it's a file
1662                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1663                                 $errors[] = array( 'movenotallowedfile' );
1664                         }
1665
1666                         if ( !$user->isAllowed( 'move' ) ) {
1667                                 // User can't move anything
1668                                 global $wgGroupPermissions;
1669                                 $userCanMove = false;
1670                                 if ( isset( $wgGroupPermissions['user']['move'] ) ) {
1671                                         $userCanMove = $wgGroupPermissions['user']['move'];
1672                                 }
1673                                 $autoconfirmedCanMove = false;
1674                                 if ( isset( $wgGroupPermissions['autoconfirmed']['move'] ) ) {
1675                                         $autoconfirmedCanMove = $wgGroupPermissions['autoconfirmed']['move'];
1676                                 }
1677                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1678                                         // custom message if logged-in users without any special rights can move
1679                                         $errors[] = array( 'movenologintext' );
1680                                 } else {
1681                                         $errors[] = array( 'movenotallowed' );
1682                                 }
1683                         }
1684                 } elseif ( $action == 'move-target' ) {
1685                         if ( !$user->isAllowed( 'move' ) ) {
1686                                 // User can't move anything
1687                                 $errors[] = array( 'movenotallowed' );
1688                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1689                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1690                                 // Show user page-specific message only if the user can move other pages
1691                                 $errors[] = array( 'cant-move-to-user-page' );
1692                         }
1693                 } elseif ( !$user->isAllowed( $action ) ) {
1694                         $errors[] = $this->missingPermissionError( $action, $short );
1695                 }
1696
1697                 return $errors;
1698         }
1699
1700         /**
1701          * Add the resulting error code to the errors array
1702          *
1703          * @param $errors Array list of current errors
1704          * @param $result Mixed result of errors
1705          *
1706          * @return Array list of errors
1707          */
1708         private function resultToError( $errors, $result ) {
1709                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1710                         // A single array representing an error
1711                         $errors[] = $result;
1712                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
1713                         // A nested array representing multiple errors
1714                         $errors = array_merge( $errors, $result );
1715                 } elseif ( $result !== '' && is_string( $result ) ) {
1716                         // A string representing a message-id
1717                         $errors[] = array( $result );
1718                 } elseif ( $result === false ) {
1719                         // a generic "We don't want them to do that"
1720                         $errors[] = array( 'badaccess-group0' );
1721                 }
1722                 return $errors;
1723         }
1724
1725         /**
1726          * Check various permission hooks
1727          *
1728          * @param $action String the action to check
1729          * @param $user User user to check
1730          * @param $errors Array list of current errors
1731          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1732          * @param $short Boolean short circuit on first error
1733          *
1734          * @return Array list of errors
1735          */
1736         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
1737                 // Use getUserPermissionsErrors instead
1738                 $result = '';
1739                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
1740                         return $result ? array() : array( array( 'badaccess-group0' ) );
1741                 }
1742                 // Check getUserPermissionsErrors hook
1743                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
1744                         $errors = $this->resultToError( $errors, $result );
1745                 }
1746                 // Check getUserPermissionsErrorsExpensive hook
1747                 if ( $doExpensiveQueries && !( $short && count( $errors ) > 0 ) &&
1748                          !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) ) ) {
1749                         $errors = $this->resultToError( $errors, $result );
1750                 }
1751
1752                 return $errors;
1753         }
1754
1755         /**
1756          * Check permissions on special pages & namespaces
1757          *
1758          * @param $action String the action to check
1759          * @param $user User user to check
1760          * @param $errors Array list of current errors
1761          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1762          * @param $short Boolean short circuit on first error
1763          *
1764          * @return Array list of errors
1765          */
1766         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1767                 # Only 'createaccount' and 'execute' can be performed on
1768                 # special pages, which don't actually exist in the DB.
1769                 $specialOKActions = array( 'createaccount', 'execute', 'read' );
1770                 if ( NS_SPECIAL == $this->mNamespace && !in_array( $action, $specialOKActions ) ) {
1771                         $errors[] = array( 'ns-specialprotected' );
1772                 }
1773
1774                 # Check $wgNamespaceProtection for restricted namespaces
1775                 if ( $this->isNamespaceProtected( $user ) ) {
1776                         $ns = $this->mNamespace == NS_MAIN ?
1777                                 wfMsg( 'nstab-main' ) : $this->getNsText();
1778                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
1779                                 array( 'protectedinterface' ) : array( 'namespaceprotected',  $ns );
1780                 }
1781
1782                 return $errors;
1783         }
1784
1785         /**
1786          * Check CSS/JS sub-page permissions
1787          *
1788          * @param $action String the action to check
1789          * @param $user User user to check
1790          * @param $errors Array list of current errors
1791          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1792          * @param $short Boolean short circuit on first error
1793          *
1794          * @return Array list of errors
1795          */
1796         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1797                 # Protect css/js subpages of user pages
1798                 # XXX: this might be better using restrictions
1799                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
1800                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' )
1801                                 && !preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
1802                         if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
1803                                 $errors[] = array( 'customcssprotected' );
1804                         } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
1805                                 $errors[] = array( 'customjsprotected' );
1806                         }
1807                 }
1808
1809                 return $errors;
1810         }
1811
1812         /**
1813          * Check against page_restrictions table requirements on this
1814          * page. The user must possess all required rights for this
1815          * action.
1816          *
1817          * @param $action String the action to check
1818          * @param $user User user to check
1819          * @param $errors Array list of current errors
1820          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1821          * @param $short Boolean short circuit on first error
1822          *
1823          * @return Array list of errors
1824          */
1825         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1826                 foreach ( $this->getRestrictions( $action ) as $right ) {
1827                         // Backwards compatibility, rewrite sysop -> protect
1828                         if ( $right == 'sysop' ) {
1829                                 $right = 'protect';
1830                         }
1831                         if ( $right != '' && !$user->isAllowed( $right ) ) {
1832                                 // Users with 'editprotected' permission can edit protected pages
1833                                 // without cascading option turned on.
1834                                 if ( $action != 'edit' || !$user->isAllowed( 'editprotected' )
1835                                         || $this->mCascadeRestriction )
1836                                 {
1837                                         $errors[] = array( 'protectedpagetext', $right );
1838                                 }
1839                         }
1840                 }
1841
1842                 return $errors;
1843         }
1844
1845         /**
1846          * Check restrictions on cascading pages.
1847          *
1848          * @param $action String the action to check
1849          * @param $user User to check
1850          * @param $errors Array list of current errors
1851          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1852          * @param $short Boolean short circuit on first error
1853          *
1854          * @return Array list of errors
1855          */
1856         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1857                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
1858                         # We /could/ use the protection level on the source page, but it's
1859                         # fairly ugly as we have to establish a precedence hierarchy for pages
1860                         # included by multiple cascade-protected pages. So just restrict
1861                         # it to people with 'protect' permission, as they could remove the
1862                         # protection anyway.
1863                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
1864                         # Cascading protection depends on more than this page...
1865                         # Several cascading protected pages may include this page...
1866                         # Check each cascading level
1867                         # This is only for protection restrictions, not for all actions
1868                         if ( isset( $restrictions[$action] ) ) {
1869                                 foreach ( $restrictions[$action] as $right ) {
1870                                         $right = ( $right == 'sysop' ) ? 'protect' : $right;
1871                                         if ( $right != '' && !$user->isAllowed( $right ) ) {
1872                                                 $pages = '';
1873                                                 foreach ( $cascadingSources as $page )
1874                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
1875                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
1876                                         }
1877                                 }
1878                         }
1879                 }
1880
1881                 return $errors;
1882         }
1883
1884         /**
1885          * Check action permissions not already checked in checkQuickPermissions
1886          *
1887          * @param $action String the action to check
1888          * @param $user User to check
1889          * @param $errors Array list of current errors
1890          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1891          * @param $short Boolean short circuit on first error
1892          *
1893          * @return Array list of errors
1894          */
1895         private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1896                 global $wgDeleteRevisionsLimit, $wgLang;
1897
1898                 if ( $action == 'protect' ) {
1899                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $doExpensiveQueries, true ) ) ) {
1900                                 // If they can't edit, they shouldn't protect.
1901                                 $errors[] = array( 'protect-cantedit' );
1902                         }
1903                 } elseif ( $action == 'create' ) {
1904                         $title_protection = $this->getTitleProtection();
1905                         if( $title_protection ) {
1906                                 if( $title_protection['pt_create_perm'] == 'sysop' ) {
1907                                         $title_protection['pt_create_perm'] = 'protect'; // B/C
1908                                 }
1909                                 if( $title_protection['pt_create_perm'] == '' ||
1910                                         !$user->isAllowed( $title_protection['pt_create_perm'] ) )
1911                                 {
1912                                         $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
1913                                 }
1914                         }
1915                 } elseif ( $action == 'move' ) {
1916                         // Check for immobile pages
1917                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
1918                                 // Specific message for this case
1919                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
1920                         } elseif ( !$this->isMovable() ) {
1921                                 // Less specific message for rarer cases
1922                                 $errors[] = array( 'immobile-source-page' );
1923                         }
1924                 } elseif ( $action == 'move-target' ) {
1925                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
1926                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
1927                         } elseif ( !$this->isMovable() ) {
1928                                 $errors[] = array( 'immobile-target-page' );
1929                         }
1930                 } elseif ( $action == 'delete' ) {
1931                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
1932                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion() )
1933                         {
1934                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
1935                         }
1936                 }
1937                 return $errors;
1938         }
1939
1940         /**
1941          * Check that the user isn't blocked from editting.
1942          *
1943          * @param $action String the action to check
1944          * @param $user User to check
1945          * @param $errors Array list of current errors
1946          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1947          * @param $short Boolean short circuit on first error
1948          *
1949          * @return Array list of errors
1950          */
1951         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
1952                 // Account creation blocks handled at userlogin.
1953                 // Unblocking handled in SpecialUnblock
1954                 if( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
1955                         return $errors;
1956                 }
1957
1958                 global $wgContLang, $wgLang, $wgEmailConfirmToEdit;
1959
1960                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
1961                         $errors[] = array( 'confirmedittext' );
1962                 }
1963
1964                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
1965                         // Don't block the user from editing their own talk page unless they've been
1966                         // explicitly blocked from that too.
1967                 } elseif( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
1968                         $block = $user->getBlock();
1969
1970                         // This is from OutputPage::blockedPage
1971                         // Copied at r23888 by werdna
1972
1973                         $id = $user->blockedBy();
1974                         $reason = $user->blockedFor();
1975                         if ( $reason == '' ) {
1976                                 $reason = wfMsg( 'blockednoreason' );
1977                         }
1978                         $ip = $user->getRequest()->getIP();
1979
1980                         if ( is_numeric( $id ) ) {
1981                                 $name = User::whoIs( $id );
1982                         } else {
1983                                 $name = $id;
1984                         }
1985
1986                         $link = '[[' . $wgContLang->getNsText( NS_USER ) . ":{$name}|{$name}]]";
1987                         $blockid = $block->getId();
1988                         $blockExpiry = $block->getExpiry();
1989                         $blockTimestamp = $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true );
1990                         if ( $blockExpiry == 'infinity' ) {
1991                                 $blockExpiry = wfMessage( 'infiniteblock' )->text();
1992                         } else {
1993                                 $blockExpiry = $wgLang->timeanddate( wfTimestamp( TS_MW, $blockExpiry ), true );
1994                         }
1995
1996                         $intended = strval( $block->getTarget() );
1997
1998                         $errors[] = array( ( $block->mAuto ? 'autoblockedtext' : 'blockedtext' ), $link, $reason, $ip, $name,
1999                                 $blockid, $blockExpiry, $intended, $blockTimestamp );
2000                 }
2001
2002                 return $errors;
2003         }
2004
2005         /**
2006          * Check that the user is allowed to read this page.
2007          *
2008          * @param $action String the action to check
2009          * @param $user User to check
2010          * @param $errors Array list of current errors
2011          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2012          * @param $short Boolean short circuit on first error
2013          *
2014          * @return Array list of errors
2015          */
2016         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2017                 global $wgWhitelistRead, $wgGroupPermissions, $wgRevokePermissions;
2018                 static $useShortcut = null;
2019
2020                 # Initialize the $useShortcut boolean, to determine if we can skip quite a bit of code below
2021                 if ( is_null( $useShortcut ) ) {
2022                         $useShortcut = true;
2023                         if ( empty( $wgGroupPermissions['*']['read'] ) ) {
2024                                 # Not a public wiki, so no shortcut
2025                                 $useShortcut = false;
2026                         } elseif ( !empty( $wgRevokePermissions ) ) {
2027                                 /**
2028                                  * Iterate through each group with permissions being revoked (key not included since we don't care
2029                                  * what the group name is), then check if the read permission is being revoked. If it is, then
2030                                  * we don't use the shortcut below since the user might not be able to read, even though anon
2031                                  * reading is allowed.
2032                                  */
2033                                 foreach ( $wgRevokePermissions as $perms ) {
2034                                         if ( !empty( $perms['read'] ) ) {
2035                                                 # We might be removing the read right from the user, so no shortcut
2036                                                 $useShortcut = false;
2037                                                 break;
2038                                         }
2039                                 }
2040                         }
2041                 }
2042
2043                 $whitelisted = false;
2044                 if ( $useShortcut ) {
2045                         # Shortcut for public wikis, allows skipping quite a bit of code
2046                         $whitelisted = true;
2047                 } elseif ( $user->isAllowed( 'read' ) ) {
2048                         # If the user is allowed to read pages, he is allowed to read all pages
2049                         $whitelisted = true;
2050                 } elseif ( $this->isSpecial( 'Userlogin' )
2051                         || $this->isSpecial( 'ChangePassword' )
2052                         || $this->isSpecial( 'PasswordReset' )
2053                 ) {
2054                         # Always grant access to the login page.
2055                         # Even anons need to be able to log in.
2056                         $whitelisted = true;
2057                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2058                         # Time to check the whitelist
2059                         # Only do these checks is there's something to check against
2060                         $name = $this->getPrefixedText();
2061                         $dbName = $this->getPrefixedDBKey();
2062
2063                         // Check for explicit whitelisting with and without underscores
2064                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2065                                 $whitelisted = true;
2066                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2067                                 # Old settings might have the title prefixed with
2068                                 # a colon for main-namespace pages
2069                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2070                                         $whitelisted = true;
2071                                 }
2072                         } elseif ( $this->isSpecialPage() ) {
2073                                 # If it's a special page, ditch the subpage bit and check again
2074                                 $name = $this->getDBkey();
2075                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2076                                 if ( $name !== false ) {
2077                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2078                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2079                                                 $whitelisted = true;
2080                                         }
2081                                 }
2082                         }
2083                 }
2084
2085                 if ( !$whitelisted ) {
2086                         # If the title is not whitelisted, give extensions a chance to do so...
2087                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2088                         if ( !$whitelisted ) {
2089                                 $errors[] = $this->missingPermissionError( $action, $short );
2090                         }
2091                 }
2092
2093                 return $errors;
2094         }
2095
2096         /**
2097          * Get a description array when the user doesn't have the right to perform
2098          * $action (i.e. when User::isAllowed() returns false)
2099          *
2100          * @param $action String the action to check
2101          * @param $short Boolean short circuit on first error
2102          * @return Array list of errors
2103          */
2104         private function missingPermissionError( $action, $short ) {
2105                 // We avoid expensive display logic for quickUserCan's and such
2106                 if ( $short ) {
2107                         return array( 'badaccess-group0' );
2108                 }
2109
2110                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2111                         User::getGroupsWithPermission( $action ) );
2112
2113                 if ( count( $groups ) ) {
2114                         global $wgLang;
2115                         return array(
2116                                 'badaccess-groups',
2117                                 $wgLang->commaList( $groups ),
2118                                 count( $groups )
2119                         );
2120                 } else {
2121                         return array( 'badaccess-group0' );
2122                 }
2123         }
2124
2125         /**
2126          * Can $user perform $action on this page? This is an internal function,
2127          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2128          * checks on wfReadOnly() and blocks)
2129          *
2130          * @param $action String action that permission needs to be checked for
2131          * @param $user User to check
2132          * @param $doExpensiveQueries Bool Set this to false to avoid doing unnecessary queries.
2133          * @param $short Bool Set this to true to stop after the first permission error.
2134          * @return Array of arrays of the arguments to wfMsg to explain permissions problems.
2135          */
2136         protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
2137                 wfProfileIn( __METHOD__ );
2138
2139                 # Read has special handling
2140                 if ( $action == 'read' ) {
2141                         $checks = array(
2142                                 'checkPermissionHooks',
2143                                 'checkReadPermissions',
2144                         );
2145                 } else {
2146                         $checks = array(
2147                                 'checkQuickPermissions',
2148                                 'checkPermissionHooks',
2149                                 'checkSpecialsAndNSPermissions',
2150                                 'checkCSSandJSPermissions',
2151                                 'checkPageRestrictions',
2152                                 'checkCascadingSourcesRestrictions',
2153                                 'checkActionPermissions',
2154                                 'checkUserBlock'
2155                         );
2156                 }
2157
2158                 $errors = array();
2159                 while( count( $checks ) > 0 &&
2160                                 !( $short && count( $errors ) > 0 ) ) {
2161                         $method = array_shift( $checks );
2162                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2163                 }
2164
2165                 wfProfileOut( __METHOD__ );
2166                 return $errors;
2167         }
2168
2169         /**
2170          * Protect css subpages of user pages: can $wgUser edit
2171          * this page?
2172          *
2173          * @deprecated in 1.19; will be removed in 1.20. Use getUserPermissionsErrors() instead.
2174          * @return Bool
2175          */
2176         public function userCanEditCssSubpage() {
2177                 global $wgUser;
2178                 wfDeprecated( __METHOD__, '1.19' );
2179                 return ( ( $wgUser->isAllowedAll( 'editusercssjs', 'editusercss' ) )
2180                         || preg_match( '/^' . preg_quote( $wgUser->getName(), '/' ) . '\//', $this->mTextform ) );
2181         }
2182
2183         /**
2184          * Protect js subpages of user pages: can $wgUser edit
2185          * this page?
2186          *
2187          * @deprecated in 1.19; will be removed in 1.20. Use getUserPermissionsErrors() instead.
2188          * @return Bool
2189          */
2190         public function userCanEditJsSubpage() {
2191                 global $wgUser;
2192                 wfDeprecated( __METHOD__, '1.19' );
2193                 return ( ( $wgUser->isAllowedAll( 'editusercssjs', 'edituserjs' ) )
2194                            || preg_match( '/^' . preg_quote( $wgUser->getName(), '/' ) . '\//', $this->mTextform ) );
2195         }
2196
2197         /**
2198          * Get a filtered list of all restriction types supported by this wiki.
2199          * @param bool $exists True to get all restriction types that apply to
2200          * titles that do exist, False for all restriction types that apply to
2201          * titles that do not exist
2202          * @return array
2203          */
2204         public static function getFilteredRestrictionTypes( $exists = true ) {
2205                 global $wgRestrictionTypes;
2206                 $types = $wgRestrictionTypes;
2207                 if ( $exists ) {
2208                         # Remove the create restriction for existing titles
2209                         $types = array_diff( $types, array( 'create' ) );
2210                 } else {
2211                         # Only the create and upload restrictions apply to non-existing titles
2212                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2213                 }
2214                 return $types;
2215         }
2216
2217         /**
2218          * Returns restriction types for the current Title
2219          *
2220          * @return array applicable restriction types
2221          */
2222         public function getRestrictionTypes() {
2223                 if ( $this->isSpecialPage() ) {
2224                         return array();
2225                 }
2226
2227                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2228
2229                 if ( $this->getNamespace() != NS_FILE ) {
2230                         # Remove the upload restriction for non-file titles
2231                         $types = array_diff( $types, array( 'upload' ) );
2232                 }
2233
2234                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2235
2236                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2237                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2238
2239                 return $types;
2240         }
2241
2242         /**
2243          * Is this title subject to title protection?
2244          * Title protection is the one applied against creation of such title.
2245          *
2246          * @return Mixed An associative array representing any existent title
2247          *   protection, or false if there's none.
2248          */
2249         private function getTitleProtection() {
2250                 // Can't protect pages in special namespaces
2251                 if ( $this->getNamespace() < 0 ) {
2252                         return false;
2253                 }
2254
2255                 // Can't protect pages that exist.
2256                 if ( $this->exists() ) {
2257                         return false;
2258                 }
2259
2260                 if ( !isset( $this->mTitleProtection ) ) {
2261                         $dbr = wfGetDB( DB_SLAVE );
2262                         $res = $dbr->select( 'protected_titles', '*',
2263                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2264                                 __METHOD__ );
2265
2266                         // fetchRow returns false if there are no rows.
2267                         $this->mTitleProtection = $dbr->fetchRow( $res );
2268                 }
2269                 return $this->mTitleProtection;
2270         }
2271
2272         /**
2273          * Update the title protection status
2274          *
2275          * @deprecated in 1.19; will be removed in 1.20. Use WikiPage::doUpdateRestrictions() instead.
2276          * @param $create_perm String Permission required for creation
2277          * @param $reason String Reason for protection
2278          * @param $expiry String Expiry timestamp
2279          * @return boolean true
2280          */
2281         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2282                 wfDeprecated( __METHOD__, '1.19' );
2283
2284                 global $wgUser;
2285
2286                 $limit = array( 'create' => $create_perm );
2287                 $expiry = array( 'create' => $expiry );
2288
2289                 $page = WikiPage::factory( $this );
2290                 $status = $page->doUpdateRestrictions( $limit, $expiry, false, $reason, $wgUser );
2291
2292                 return $status->isOK();
2293         }
2294
2295         /**
2296          * Remove any title protection due to page existing
2297          */
2298         public function deleteTitleProtection() {
2299                 $dbw = wfGetDB( DB_MASTER );
2300
2301                 $dbw->delete(
2302                         'protected_titles',
2303                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2304                         __METHOD__
2305                 );
2306                 $this->mTitleProtection = false;
2307         }
2308
2309         /**
2310          * Is this page "semi-protected" - the *only* protection is autoconfirm?
2311          *
2312          * @param $action String Action to check (default: edit)
2313          * @return Bool
2314          */
2315         public function isSemiProtected( $action = 'edit' ) {
2316                 if ( $this->exists() ) {
2317                         $restrictions = $this->getRestrictions( $action );
2318                         if ( count( $restrictions ) > 0 ) {
2319                                 foreach ( $restrictions as $restriction ) {
2320                                         if ( strtolower( $restriction ) != 'autoconfirmed' ) {
2321                                                 return false;
2322                                         }
2323                                 }
2324                         } else {
2325                                 # Not protected
2326                                 return false;
2327                         }
2328                         return true;
2329                 } else {
2330                         # If it doesn't exist, it can't be protected
2331                         return false;
2332                 }
2333         }
2334
2335         /**
2336          * Does the title correspond to a protected article?
2337          *
2338          * @param $action String the action the page is protected from,
2339          * by default checks all actions.
2340          * @return Bool
2341          */
2342         public function isProtected( $action = '' ) {
2343                 global $wgRestrictionLevels;
2344
2345                 $restrictionTypes = $this->getRestrictionTypes();
2346
2347                 # Special pages have inherent protection
2348                 if( $this->isSpecialPage() ) {
2349                         return true;
2350                 }
2351
2352                 # Check regular protection levels
2353                 foreach ( $restrictionTypes as $type ) {
2354                         if ( $action == $type || $action == '' ) {
2355                                 $r = $this->getRestrictions( $type );
2356                                 foreach ( $wgRestrictionLevels as $level ) {
2357                                         if ( in_array( $level, $r ) && $level != '' ) {
2358                                                 return true;
2359                                         }
2360                                 }
2361                         }
2362                 }
2363
2364                 return false;
2365         }
2366
2367         /**
2368          * Determines if $user is unable to edit this page because it has been protected
2369          * by $wgNamespaceProtection.
2370          *
2371          * @param $user User object to check permissions
2372          * @return Bool
2373          */
2374         public function isNamespaceProtected( User $user ) {
2375                 global $wgNamespaceProtection;
2376
2377                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2378                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2379                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2380                                         return true;
2381                                 }
2382                         }
2383                 }
2384                 return false;
2385         }
2386
2387         /**
2388          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2389          *
2390          * @return Bool If the page is subject to cascading restrictions.
2391          */
2392         public function isCascadeProtected() {
2393                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2394                 return ( $sources > 0 );
2395         }
2396
2397         /**
2398          * Cascading protection: Get the source of any cascading restrictions on this page.
2399          *
2400          * @param $getPages Bool Whether or not to retrieve the actual pages
2401          *        that the restrictions have come from.
2402          * @return Mixed Array of Title objects of the pages from which cascading restrictions
2403          *     have come, false for none, or true if such restrictions exist, but $getPages
2404          *     was not set.  The restriction array is an array of each type, each of which
2405          *     contains a array of unique groups.
2406          */
2407         public function getCascadeProtectionSources( $getPages = true ) {
2408                 global $wgContLang;
2409                 $pagerestrictions = array();
2410
2411                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2412                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2413                 } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2414                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2415                 }
2416
2417                 wfProfileIn( __METHOD__ );
2418
2419                 $dbr = wfGetDB( DB_SLAVE );
2420
2421                 if ( $this->getNamespace() == NS_FILE ) {
2422                         $tables = array( 'imagelinks', 'page_restrictions' );
2423                         $where_clauses = array(
2424                                 'il_to' => $this->getDBkey(),
2425                                 'il_from=pr_page',
2426                                 'pr_cascade' => 1
2427                         );
2428                 } else {
2429                         $tables = array( 'templatelinks', 'page_restrictions' );
2430                         $where_clauses = array(
2431                                 'tl_namespace' => $this->getNamespace(),
2432                                 'tl_title' => $this->getDBkey(),
2433                                 'tl_from=pr_page',
2434                                 'pr_cascade' => 1
2435                         );
2436                 }
2437
2438                 if ( $getPages ) {
2439                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2440                                                    'pr_expiry', 'pr_type', 'pr_level' );
2441                         $where_clauses[] = 'page_id=pr_page';
2442                         $tables[] = 'page';
2443                 } else {
2444                         $cols = array( 'pr_expiry' );
2445                 }
2446
2447                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2448
2449                 $sources = $getPages ? array() : false;
2450                 $now = wfTimestampNow();
2451                 $purgeExpired = false;
2452
2453                 foreach ( $res as $row ) {
2454                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2455                         if ( $expiry > $now ) {
2456                                 if ( $getPages ) {
2457                                         $page_id = $row->pr_page;
2458                                         $page_ns = $row->page_namespace;
2459                                         $page_title = $row->page_title;
2460                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2461                                         # Add groups needed for each restriction type if its not already there
2462                                         # Make sure this restriction type still exists
2463
2464                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2465                                                 $pagerestrictions[$row->pr_type] = array();
2466                                         }
2467
2468                                         if ( isset( $pagerestrictions[$row->pr_type] ) &&
2469                                                  !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] ) ) {
2470                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2471                                         }
2472                                 } else {
2473                                         $sources = true;
2474                                 }
2475                         } else {
2476                                 // Trigger lazy purge of expired restrictions from the db
2477                                 $purgeExpired = true;
2478                         }
2479                 }
2480                 if ( $purgeExpired ) {
2481                         Title::purgeExpiredRestrictions();
2482                 }
2483
2484                 if ( $getPages ) {
2485                         $this->mCascadeSources = $sources;
2486                         $this->mCascadingRestrictions = $pagerestrictions;
2487                 } else {
2488                         $this->mHasCascadingRestrictions = $sources;
2489                 }
2490
2491                 wfProfileOut( __METHOD__ );
2492                 return array( $sources, $pagerestrictions );
2493         }
2494
2495         /**
2496          * Accessor/initialisation for mRestrictions
2497          *
2498          * @param $action String action that permission needs to be checked for
2499          * @return Array of Strings the array of groups allowed to edit this article
2500          */
2501         public function getRestrictions( $action ) {
2502                 if ( !$this->mRestrictionsLoaded ) {
2503                         $this->loadRestrictions();
2504                 }
2505                 return isset( $this->mRestrictions[$action] )
2506                                 ? $this->mRestrictions[$action]
2507                                 : array();
2508         }
2509
2510         /**
2511          * Get the expiry time for the restriction against a given action
2512          *
2513          * @return String|Bool 14-char timestamp, or 'infinity' if the page is protected forever
2514          *      or not protected at all, or false if the action is not recognised.
2515          */
2516         public function getRestrictionExpiry( $action ) {
2517                 if ( !$this->mRestrictionsLoaded ) {
2518                         $this->loadRestrictions();
2519                 }
2520                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2521         }
2522
2523         /**
2524          * Returns cascading restrictions for the current article
2525          *
2526          * @return Boolean
2527          */
2528         function areRestrictionsCascading() {
2529                 if ( !$this->mRestrictionsLoaded ) {
2530                         $this->loadRestrictions();
2531                 }
2532
2533                 return $this->mCascadeRestriction;
2534         }
2535
2536         /**
2537          * Loads a string into mRestrictions array
2538          *
2539          * @param $res Resource restrictions as an SQL result.
2540          * @param $oldFashionedRestrictions String comma-separated list of page
2541          *        restrictions from page table (pre 1.10)
2542          */
2543         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2544                 $rows = array();
2545
2546                 foreach ( $res as $row ) {
2547                         $rows[] = $row;
2548                 }
2549
2550                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2551         }
2552
2553         /**
2554          * Compiles list of active page restrictions from both page table (pre 1.10)
2555          * and page_restrictions table for this existing page.
2556          * Public for usage by LiquidThreads.
2557          *
2558          * @param $rows array of db result objects
2559          * @param $oldFashionedRestrictions string comma-separated list of page
2560          *        restrictions from page table (pre 1.10)
2561          */
2562         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2563                 global $wgContLang;
2564                 $dbr = wfGetDB( DB_SLAVE );
2565
2566                 $restrictionTypes = $this->getRestrictionTypes();
2567
2568                 foreach ( $restrictionTypes as $type ) {
2569                         $this->mRestrictions[$type] = array();
2570                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2571                 }
2572
2573                 $this->mCascadeRestriction = false;
2574
2575                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2576
2577                 if ( $oldFashionedRestrictions === null ) {
2578                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2579                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2580                 }
2581
2582                 if ( $oldFashionedRestrictions != '' ) {
2583
2584                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2585                                 $temp = explode( '=', trim( $restrict ) );
2586                                 if ( count( $temp ) == 1 ) {
2587                                         // old old format should be treated as edit/move restriction
2588                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2589                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2590                                 } else {
2591                                         $this->mRestrictions[$temp[0]] = explode( ',', trim( $temp[1] ) );
2592                                 }
2593                         }
2594
2595                         $this->mOldRestrictions = true;
2596
2597                 }
2598
2599                 if ( count( $rows ) ) {
2600                         # Current system - load second to make them override.
2601                         $now = wfTimestampNow();
2602                         $purgeExpired = false;
2603
2604                         # Cycle through all the restrictions.
2605                         foreach ( $rows as $row ) {
2606
2607                                 // Don't take care of restrictions types that aren't allowed
2608                                 if ( !in_array( $row->pr_type, $restrictionTypes ) )
2609                                         continue;
2610
2611                                 // This code should be refactored, now that it's being used more generally,
2612                                 // But I don't really see any harm in leaving it in Block for now -werdna
2613                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2614
2615                                 // Only apply the restrictions if they haven't expired!
2616                                 if ( !$expiry || $expiry > $now ) {
2617                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2618                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2619
2620                                         $this->mCascadeRestriction |= $row->pr_cascade;
2621                                 } else {
2622                                         // Trigger a lazy purge of expired restrictions
2623                                         $purgeExpired = true;
2624                                 }
2625                         }
2626
2627                         if ( $purgeExpired ) {
2628                                 Title::purgeExpiredRestrictions();
2629                         }
2630                 }
2631
2632                 $this->mRestrictionsLoaded = true;
2633         }
2634
2635         /**
2636          * Load restrictions from the page_restrictions table
2637          *
2638          * @param $oldFashionedRestrictions String comma-separated list of page
2639          *        restrictions from page table (pre 1.10)
2640          */
2641         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2642                 global $wgContLang;
2643                 if ( !$this->mRestrictionsLoaded ) {
2644                         if ( $this->exists() ) {
2645                                 $dbr = wfGetDB( DB_SLAVE );
2646
2647                                 $res = $dbr->select(
2648                                         'page_restrictions',
2649                                         '*',
2650                                         array( 'pr_page' => $this->getArticleID() ),
2651                                         __METHOD__
2652                                 );
2653
2654                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2655                         } else {
2656                                 $title_protection = $this->getTitleProtection();
2657
2658                                 if ( $title_protection ) {
2659                                         $now = wfTimestampNow();
2660                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2661
2662                                         if ( !$expiry || $expiry > $now ) {
2663                                                 // Apply the restrictions
2664                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2665                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2666                                         } else { // Get rid of the old restrictions
2667                                                 Title::purgeExpiredRestrictions();
2668                                                 $this->mTitleProtection = false;
2669                                         }
2670                                 } else {
2671                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2672                                 }
2673                                 $this->mRestrictionsLoaded = true;
2674                         }
2675                 }
2676         }
2677
2678         /**
2679          * Flush the protection cache in this object and force reload from the database.
2680          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2681          */
2682         public function flushRestrictions() {
2683                 $this->mRestrictionsLoaded = false;
2684                 $this->mTitleProtection = null;
2685         }
2686
2687         /**
2688          * Purge expired restrictions from the page_restrictions table
2689          */
2690         static function purgeExpiredRestrictions() {
2691                 $dbw = wfGetDB( DB_MASTER );
2692                 $dbw->delete(
2693                         'page_restrictions',
2694                         array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2695                         __METHOD__
2696                 );
2697
2698                 $dbw->delete(
2699                         'protected_titles',
2700                         array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2701                         __METHOD__
2702                 );
2703         }
2704
2705         /**
2706          * Does this have subpages?  (Warning, usually requires an extra DB query.)
2707          *
2708          * @return Bool
2709          */
2710         public function hasSubpages() {
2711                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
2712                         # Duh
2713                         return false;
2714                 }
2715
2716                 # We dynamically add a member variable for the purpose of this method
2717                 # alone to cache the result.  There's no point in having it hanging
2718                 # around uninitialized in every Title object; therefore we only add it
2719                 # if needed and don't declare it statically.
2720                 if ( isset( $this->mHasSubpages ) ) {
2721                         return $this->mHasSubpages;
2722                 }
2723
2724                 $subpages = $this->getSubpages( 1 );
2725                 if ( $subpages instanceof TitleArray ) {
2726                         return $this->mHasSubpages = (bool)$subpages->count();
2727                 }
2728                 return $this->mHasSubpages = false;
2729         }
2730
2731         /**
2732          * Get all subpages of this page.
2733          *
2734          * @param $limit Int maximum number of subpages to fetch; -1 for no limit
2735          * @return mixed TitleArray, or empty array if this page's namespace
2736          *  doesn't allow subpages
2737          */
2738         public function getSubpages( $limit = -1 ) {
2739                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
2740                         return array();
2741                 }
2742
2743                 $dbr = wfGetDB( DB_SLAVE );
2744                 $conds['page_namespace'] = $this->getNamespace();
2745                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
2746                 $options = array();
2747                 if ( $limit > -1 ) {
2748                         $options['LIMIT'] = $limit;
2749                 }
2750                 return $this->mSubpages = TitleArray::newFromResult(
2751                         $dbr->select( 'page',
2752                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
2753                                 $conds,
2754                                 __METHOD__,
2755                                 $options
2756                         )
2757                 );
2758         }
2759
2760         /**
2761          * Is there a version of this page in the deletion archive?
2762          *
2763          * @return Int the number of archived revisions
2764          */
2765         public function isDeleted() {
2766                 if ( $this->getNamespace() < 0 ) {
2767                         $n = 0;
2768                 } else {
2769                         $dbr = wfGetDB( DB_SLAVE );
2770
2771                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
2772                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2773                                 __METHOD__
2774                         );
2775                         if ( $this->getNamespace() == NS_FILE ) {
2776                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
2777                                         array( 'fa_name' => $this->getDBkey() ),
2778                                         __METHOD__
2779                                 );
2780                         }
2781                 }
2782                 return (int)$n;
2783         }
2784
2785         /**
2786          * Is there a version of this page in the deletion archive?
2787          *
2788          * @return Boolean
2789          */
2790         public function isDeletedQuick() {
2791                 if ( $this->getNamespace() < 0 ) {
2792                         return false;
2793                 }
2794                 $dbr = wfGetDB( DB_SLAVE );
2795                 $deleted = (bool)$dbr->selectField( 'archive', '1',
2796                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2797                         __METHOD__
2798                 );
2799                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
2800                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
2801                                 array( 'fa_name' => $this->getDBkey() ),
2802                                 __METHOD__
2803                         );
2804                 }
2805                 return $deleted;
2806         }
2807
2808         /**
2809          * Get the article ID for this Title from the link cache,
2810          * adding it if necessary
2811          *
2812          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select
2813          *  for update
2814          * @return Int the ID
2815          */
2816         public function getArticleID( $flags = 0 ) {
2817                 if ( $this->getNamespace() < 0 ) {
2818                         return $this->mArticleID = 0;
2819                 }
2820                 $linkCache = LinkCache::singleton();
2821                 if ( $flags & self::GAID_FOR_UPDATE ) {
2822                         $oldUpdate = $linkCache->forUpdate( true );
2823                         $linkCache->clearLink( $this );
2824                         $this->mArticleID = $linkCache->addLinkObj( $this );
2825                         $linkCache->forUpdate( $oldUpdate );
2826                 } else {
2827                         if ( -1 == $this->mArticleID ) {
2828                                 $this->mArticleID = $linkCache->addLinkObj( $this );
2829                         }
2830                 }
2831                 return $this->mArticleID;
2832         }
2833
2834         /**
2835          * Is this an article that is a redirect page?
2836          * Uses link cache, adding it if necessary
2837          *
2838          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select for update
2839          * @return Bool
2840          */
2841         public function isRedirect( $flags = 0 ) {
2842                 if ( !is_null( $this->mRedirect ) ) {
2843                         return $this->mRedirect;
2844                 }
2845                 # Calling getArticleID() loads the field from cache as needed
2846                 if ( !$this->getArticleID( $flags ) ) {
2847                         return $this->mRedirect = false;
2848                 }
2849                 $linkCache = LinkCache::singleton();
2850                 $this->mRedirect = (bool)$linkCache->getGoodLinkFieldObj( $this, 'redirect' );
2851
2852                 return $this->mRedirect;
2853         }
2854
2855         /**
2856          * What is the length of this page?
2857          * Uses link cache, adding it if necessary
2858          *
2859          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select for update
2860          * @return Int
2861          */
2862         public function getLength( $flags = 0 ) {
2863                 if ( $this->mLength != -1 ) {
2864                         return $this->mLength;
2865                 }
2866                 # Calling getArticleID() loads the field from cache as needed
2867                 if ( !$this->getArticleID( $flags ) ) {
2868                         return $this->mLength = 0;
2869                 }
2870                 $linkCache = LinkCache::singleton();
2871                 $this->mLength = intval( $linkCache->getGoodLinkFieldObj( $this, 'length' ) );
2872
2873                 return $this->mLength;
2874         }
2875
2876         /**
2877          * What is the page_latest field for this page?
2878          *
2879          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select for update
2880          * @return Int or 0 if the page doesn't exist
2881          */
2882         public function getLatestRevID( $flags = 0 ) {
2883                 if ( $this->mLatestID !== false ) {
2884                         return intval( $this->mLatestID );
2885                 }
2886                 # Calling getArticleID() loads the field from cache as needed
2887                 if ( !$this->getArticleID( $flags ) ) {
2888                         return $this->mLatestID = 0;
2889                 }
2890                 $linkCache = LinkCache::singleton();
2891                 $this->mLatestID = intval( $linkCache->getGoodLinkFieldObj( $this, 'revision' ) );
2892
2893                 return $this->mLatestID;
2894         }
2895
2896         /**
2897          * This clears some fields in this object, and clears any associated
2898          * keys in the "bad links" section of the link cache.
2899          *
2900          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
2901          * loading of the new page_id. It's also called from
2902          * WikiPage::doDeleteArticle()
2903          *
2904          * @param $newid Int the new Article ID
2905          */
2906         public function resetArticleID( $newid ) {
2907                 $linkCache = LinkCache::singleton();
2908                 $linkCache->clearLink( $this );
2909
2910                 if ( $newid === false ) {
2911                         $this->mArticleID = -1;
2912                 } else {
2913                         $this->mArticleID = intval( $newid );
2914                 }
2915                 $this->mRestrictionsLoaded = false;
2916                 $this->mRestrictions = array();
2917                 $this->mRedirect = null;
2918                 $this->mLength = -1;
2919                 $this->mLatestID = false;
2920                 $this->mEstimateRevisions = null;
2921         }
2922
2923         /**
2924          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
2925          *
2926          * @param $text String containing title to capitalize
2927          * @param $ns int namespace index, defaults to NS_MAIN
2928          * @return String containing capitalized title
2929          */
2930         public static function capitalize( $text, $ns = NS_MAIN ) {
2931                 global $wgContLang;
2932
2933                 if ( MWNamespace::isCapitalized( $ns ) ) {
2934                         return $wgContLang->ucfirst( $text );
2935                 } else {
2936                         return $text;
2937                 }
2938         }
2939
2940         /**
2941          * Secure and split - main initialisation function for this object
2942          *
2943          * Assumes that mDbkeyform has been set, and is urldecoded
2944          * and uses underscores, but not otherwise munged.  This function
2945          * removes illegal characters, splits off the interwiki and
2946          * namespace prefixes, sets the other forms, and canonicalizes
2947          * everything.
2948          *
2949          * @return Bool true on success
2950          */
2951         private function secureAndSplit() {
2952                 global $wgContLang, $wgLocalInterwiki;
2953
2954                 # Initialisation
2955                 $this->mInterwiki = $this->mFragment = '';
2956                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
2957
2958                 $dbkey = $this->mDbkeyform;
2959
2960                 # Strip Unicode bidi override characters.
2961                 # Sometimes they slip into cut-n-pasted page titles, where the
2962                 # override chars get included in list displays.
2963                 $dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );
2964
2965                 # Clean up whitespace
2966                 # Note: use of the /u option on preg_replace here will cause
2967                 # input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
2968                 # conveniently disabling them.
2969                 $dbkey = preg_replace( '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u', '_', $dbkey );
2970                 $dbkey = trim( $dbkey, '_' );
2971
2972                 if ( $dbkey == '' ) {
2973                         return false;
2974                 }
2975
2976                 if ( false !== strpos( $dbkey, UTF8_REPLACEMENT ) ) {
2977                         # Contained illegal UTF-8 sequences or forbidden Unicode chars.
2978                         return false;
2979                 }
2980
2981                 $this->mDbkeyform = $dbkey;
2982
2983                 # Initial colon indicates main namespace rather than specified default
2984                 # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
2985                 if ( ':' == $dbkey[0] ) {
2986                         $this->mNamespace = NS_MAIN;
2987                         $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
2988                         $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
2989                 }
2990
2991                 # Namespace or interwiki prefix
2992                 $firstPass = true;
2993                 $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
2994                 do {
2995                         $m = array();
2996                         if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
2997                                 $p = $m[1];
2998                                 if ( ( $ns = $wgContLang->getNsIndex( $p ) ) !== false ) {
2999                                         # Ordinary namespace
3000                                         $dbkey = $m[2];
3001                                         $this->mNamespace = $ns;
3002                                         # For Talk:X pages, check if X has a "namespace" prefix
3003                                         if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
3004                                                 if ( $wgContLang->getNsIndex( $x[1] ) ) {
3005                                                         # Disallow Talk:File:x type titles...
3006                                                         return false;
3007                                                 } elseif ( Interwiki::isValidInterwiki( $x[1] ) ) {
3008                                                         # Disallow Talk:Interwiki:x type titles...
3009                                                         return false;
3010                                                 }
3011                                         }
3012                                 } elseif ( Interwiki::isValidInterwiki( $p ) ) {
3013                                         if ( !$firstPass ) {
3014                                                 # Can't make a local interwiki link to an interwiki link.
3015                                                 # That's just crazy!
3016                                                 return false;
3017                                         }
3018
3019                                         # Interwiki link
3020                                         $dbkey = $m[2];
3021                                         $this->mInterwiki = $wgContLang->lc( $p );
3022
3023                                         # Redundant interwiki prefix to the local wiki
3024                                         if ( $wgLocalInterwiki !== false
3025                                                 && 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki ) )
3026                                         {
3027                                                 if ( $dbkey == '' ) {
3028                                                         # Can't have an empty self-link
3029                                                         return false;
3030                                                 }
3031                                                 $this->mInterwiki = '';
3032                                                 $firstPass = false;
3033                                                 # Do another namespace split...
3034                                                 continue;
3035                                         }
3036
3037                                         # If there's an initial colon after the interwiki, that also
3038                                         # resets the default namespace
3039                                         if ( $dbkey !== '' && $dbkey[0] == ':' ) {
3040                                                 $this->mNamespace = NS_MAIN;
3041                                                 $dbkey = substr( $dbkey, 1 );
3042                                         }
3043                                 }
3044                                 # If there's no recognized interwiki or namespace,
3045                                 # then let the colon expression be part of the title.
3046                         }
3047                         break;
3048                 } while ( true );
3049
3050                 # We already know that some pages won't be in the database!
3051                 if ( $this->mInterwiki != '' || NS_SPECIAL == $this->mNamespace ) {
3052                         $this->mArticleID = 0;
3053                 }
3054                 $fragment = strstr( $dbkey, '#' );
3055                 if ( false !== $fragment ) {
3056                         $this->setFragment( $fragment );
3057                         $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
3058                         # remove whitespace again: prevents "Foo_bar_#"
3059                         # becoming "Foo_bar_"
3060                         $dbkey = preg_replace( '/_*$/', '', $dbkey );
3061                 }
3062
3063                 # Reject illegal characters.
3064                 $rxTc = self::getTitleInvalidRegex();
3065                 if ( preg_match( $rxTc, $dbkey ) ) {
3066                         return false;
3067                 }
3068
3069                 # Pages with "/./" or "/../" appearing in the URLs will often be un-
3070                 # reachable due to the way web browsers deal with 'relative' URLs.
3071                 # Also, they conflict with subpage syntax.  Forbid them explicitly.
3072                 if ( strpos( $dbkey, '.' ) !== false &&
3073                          ( $dbkey === '.' || $dbkey === '..' ||
3074                            strpos( $dbkey, './' ) === 0  ||
3075                            strpos( $dbkey, '../' ) === 0 ||
3076                            strpos( $dbkey, '/./' ) !== false ||
3077                            strpos( $dbkey, '/../' ) !== false  ||
3078                            substr( $dbkey, -2 ) == '/.' ||
3079                            substr( $dbkey, -3 ) == '/..' ) )
3080                 {
3081                         return false;
3082                 }
3083
3084                 # Magic tilde sequences? Nu-uh!
3085                 if ( strpos( $dbkey, '~~~' ) !== false ) {
3086                         return false;
3087                 }
3088
3089                 # Limit the size of titles to 255 bytes. This is typically the size of the
3090                 # underlying database field. We make an exception for special pages, which
3091                 # don't need to be stored in the database, and may edge over 255 bytes due
3092                 # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
3093                 if ( ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 ) ||
3094                   strlen( $dbkey ) > 512 )
3095                 {
3096                         return false;
3097                 }
3098
3099                 # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
3100                 # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
3101                 # other site might be case-sensitive.
3102                 $this->mUserCaseDBKey = $dbkey;
3103                 if ( $this->mInterwiki == '' ) {
3104                         $dbkey = self::capitalize( $dbkey, $this->mNamespace );
3105                 }
3106
3107                 # Can't make a link to a namespace alone... "empty" local links can only be
3108                 # self-links with a fragment identifier.
3109                 if ( $dbkey == '' && $this->mInterwiki == '' && $this->mNamespace != NS_MAIN ) {
3110                         return false;
3111                 }
3112
3113                 // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
3114                 // IP names are not allowed for accounts, and can only be referring to
3115                 // edits from the IP. Given '::' abbreviations and caps/lowercaps,
3116                 // there are numerous ways to present the same IP. Having sp:contribs scan
3117                 // them all is silly and having some show the edits and others not is
3118                 // inconsistent. Same for talk/userpages. Keep them normalized instead.
3119                 $dbkey = ( $this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK )
3120                         ? IP::sanitizeIP( $dbkey )
3121                         : $dbkey;
3122
3123                 // Any remaining initial :s are illegal.
3124                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3125                         return false;
3126                 }
3127
3128                 # Fill fields
3129                 $this->mDbkeyform = $dbkey;
3130                 $this->mUrlform = wfUrlencode( $dbkey );
3131
3132                 $this->mTextform = str_replace( '_', ' ', $dbkey );
3133
3134                 return true;
3135         }
3136
3137         /**
3138          * Get an array of Title objects linking to this Title
3139          * Also stores the IDs in the link cache.
3140          *
3141          * WARNING: do not use this function on arbitrary user-supplied titles!
3142          * On heavily-used templates it will max out the memory.
3143          *
3144          * @param $options Array: may be FOR UPDATE
3145          * @param $table String: table name
3146          * @param $prefix String: fields prefix
3147          * @return Array of Title objects linking here
3148          */
3149         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3150                 if ( count( $options ) > 0 ) {
3151                         $db = wfGetDB( DB_MASTER );
3152                 } else {
3153                         $db = wfGetDB( DB_SLAVE );
3154                 }
3155
3156                 $res = $db->select(
3157                         array( 'page', $table ),
3158                         array( 'page_namespace', 'page_title', 'page_id', 'page_len', 'page_is_redirect', 'page_latest' ),
3159                         array(
3160                                 "{$prefix}_from=page_id",
3161                                 "{$prefix}_namespace" => $this->getNamespace(),
3162                                 "{$prefix}_title"     => $this->getDBkey() ),
3163                         __METHOD__,
3164                         $options
3165                 );
3166
3167                 $retVal = array();
3168                 if ( $res->numRows() ) {
3169                         $linkCache = LinkCache::singleton();
3170                         foreach ( $res as $row ) {
3171                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3172                                 if ( $titleObj ) {
3173                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3174                                         $retVal[] = $titleObj;
3175                                 }
3176                         }
3177                 }
3178                 return $retVal;
3179         }
3180
3181         /**
3182          * Get an array of Title objects using this Title as a template
3183          * Also stores the IDs in the link cache.
3184          *
3185          * WARNING: do not use this function on arbitrary user-supplied titles!
3186          * On heavily-used templates it will max out the memory.
3187          *
3188          * @param $options Array: may be FOR UPDATE
3189          * @return Array of Title the Title objects linking here
3190          */
3191         public function getTemplateLinksTo( $options = array() ) {
3192                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3193         }
3194
3195         /**
3196          * Get an array of Title objects linked from this Title
3197          * Also stores the IDs in the link cache.
3198          *
3199          * WARNING: do not use this function on arbitrary user-supplied titles!
3200          * On heavily-used templates it will max out the memory.
3201          *
3202          * @param $options Array: may be FOR UPDATE
3203          * @param $table String: table name
3204          * @param $prefix String: fields prefix
3205          * @return Array of Title objects linking here
3206          */
3207         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3208                 $id = $this->getArticleID();
3209
3210                 # If the page doesn't exist; there can't be any link from this page
3211                 if ( !$id ) {
3212                         return array();
3213                 }
3214
3215                 if ( count( $options ) > 0 ) {
3216                         $db = wfGetDB( DB_MASTER );
3217                 } else {
3218                         $db = wfGetDB( DB_SLAVE );
3219                 }
3220
3221                 $namespaceFiled = "{$prefix}_namespace";
3222                 $titleField = "{$prefix}_title";
3223
3224                 $res = $db->select(
3225                         array( $table, 'page' ),
3226                         array( $namespaceFiled, $titleField, 'page_id', 'page_len', 'page_is_redirect', 'page_latest' ),
3227                         array( "{$prefix}_from" => $id ),
3228                         __METHOD__,
3229                         $options,
3230                         array( 'page' => array( 'LEFT JOIN', array( "page_namespace=$namespaceFiled", "page_title=$titleField" ) ) )
3231                 );
3232
3233                 $retVal = array();
3234                 if ( $res->numRows() ) {
3235                         $linkCache = LinkCache::singleton();
3236                         foreach ( $res as $row ) {
3237                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3238                                 if ( $titleObj ) {
3239                                         if ( $row->page_id ) {
3240                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3241                                         } else {
3242                                                 $linkCache->addBadLinkObj( $titleObj );
3243                                         }
3244                                         $retVal[] = $titleObj;
3245                                 }
3246                         }
3247                 }
3248                 return $retVal;
3249         }
3250
3251         /**
3252          * Get an array of Title objects used on this Title as a template
3253          * Also stores the IDs in the link cache.
3254          *
3255          * WARNING: do not use this function on arbitrary user-supplied titles!
3256          * On heavily-used templates it will max out the memory.
3257          *
3258          * @param $options Array: may be FOR UPDATE
3259          * @return Array of Title the Title objects used here
3260          */
3261         public function getTemplateLinksFrom( $options = array() ) {
3262                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3263         }
3264
3265         /**
3266          * Get an array of Title objects referring to non-existent articles linked from this page
3267          *
3268          * @todo check if needed (used only in SpecialBrokenRedirects.php, and should use redirect table in this case)
3269          * @return Array of Title the Title objects
3270          */
3271         public function getBrokenLinksFrom() {
3272                 if ( $this->getArticleID() == 0 ) {
3273                         # All links from article ID 0 are false positives
3274                         return array();
3275                 }
3276
3277                 $dbr = wfGetDB( DB_SLAVE );
3278                 $res = $dbr->select(
3279                         array( 'page', 'pagelinks' ),
3280                         array( 'pl_namespace', 'pl_title' ),
3281                         array(
3282                                 'pl_from' => $this->getArticleID(),
3283                                 'page_namespace IS NULL'
3284                         ),
3285                         __METHOD__, array(),
3286                         array(
3287                                 'page' => array(
3288                                         'LEFT JOIN',
3289                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3290                                 )
3291                         )
3292                 );
3293
3294                 $retVal = array();
3295                 foreach ( $res as $row ) {
3296                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3297                 }
3298                 return $retVal;
3299         }
3300
3301
3302         /**
3303          * Get a list of URLs to purge from the Squid cache when this
3304          * page changes
3305          *
3306          * @return Array of String the URLs
3307          */
3308         public function getSquidURLs() {
3309                 global $wgContLang;
3310
3311                 $urls = array(
3312                         $this->getInternalURL(),
3313                         $this->getInternalURL( 'action=history' )
3314                 );
3315
3316                 // purge variant urls as well
3317                 if ( $wgContLang->hasVariants() ) {
3318                         $variants = $wgContLang->getVariants();
3319                         foreach ( $variants as $vCode ) {
3320                                 $urls[] = $this->getInternalURL( '', $vCode );
3321                         }
3322                 }
3323
3324                 return $urls;
3325         }
3326
3327         /**
3328          * Purge all applicable Squid URLs
3329          */
3330         public function purgeSquid() {
3331                 global $wgUseSquid;
3332                 if ( $wgUseSquid ) {
3333                         $urls = $this->getSquidURLs();
3334                         $u = new SquidUpdate( $urls );
3335                         $u->doUpdate();
3336                 }
3337         }
3338
3339         /**
3340          * Move this page without authentication
3341          *
3342          * @param $nt Title the new page Title
3343          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3344          */
3345         public function moveNoAuth( &$nt ) {
3346                 return $this->moveTo( $nt, false );
3347         }
3348
3349         /**
3350          * Check whether a given move operation would be valid.
3351          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3352          *
3353          * @param $nt Title the new title
3354          * @param $auth Bool indicates whether $wgUser's permissions
3355          *  should be checked
3356          * @param $reason String is the log summary of the move, used for spam checking
3357          * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
3358          */
3359         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3360                 global $wgUser;
3361
3362                 $errors = array();
3363                 if ( !$nt ) {
3364                         // Normally we'd add this to $errors, but we'll get
3365                         // lots of syntax errors if $nt is not an object
3366                         return array( array( 'badtitletext' ) );
3367                 }
3368                 if ( $this->equals( $nt ) ) {
3369                         $errors[] = array( 'selfmove' );
3370                 }
3371                 if ( !$this->isMovable() ) {
3372                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3373                 }
3374                 if ( $nt->getInterwiki() != '' ) {
3375                         $errors[] = array( 'immobile-target-namespace-iw' );
3376                 }
3377                 if ( !$nt->isMovable() ) {
3378                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3379                 }
3380
3381                 $oldid = $this->getArticleID();
3382                 $newid = $nt->getArticleID();
3383
3384                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3385                         $errors[] = array( 'articleexists' );
3386                 }
3387                 if ( ( $this->getDBkey() == '' ) ||
3388                          ( !$oldid ) ||
3389                          ( $nt->getDBkey() == '' ) ) {
3390                         $errors[] = array( 'badarticleerror' );
3391                 }
3392
3393                 // Image-specific checks
3394                 if ( $this->getNamespace() == NS_FILE ) {
3395                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3396                 }
3397
3398                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3399                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3400                 }
3401
3402                 if ( $auth ) {
3403                         $errors = wfMergeErrorArrays( $errors,
3404                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3405                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3406                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3407                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3408                 }
3409
3410                 $match = EditPage::matchSummarySpamRegex( $reason );
3411                 if ( $match !== false ) {
3412                         // This is kind of lame, won't display nice
3413                         $errors[] = array( 'spamprotectiontext' );
3414                 }
3415
3416                 $err = null;
3417                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3418                         $errors[] = array( 'hookaborted', $err );
3419                 }
3420
3421                 # The move is allowed only if (1) the target doesn't exist, or
3422                 # (2) the target is a redirect to the source, and has no history
3423                 # (so we can undo bad moves right after they're done).
3424
3425                 if ( 0 != $newid ) { # Target exists; check for validity
3426                         if ( !$this->isValidMoveTarget( $nt ) ) {
3427                                 $errors[] = array( 'articleexists' );
3428                         }
3429                 } else {
3430                         $tp = $nt->getTitleProtection();
3431                         $right = ( $tp['pt_create_perm'] == 'sysop' ) ? 'protect' : $tp['pt_create_perm'];
3432                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3433                                 $errors[] = array( 'cantmove-titleprotected' );
3434                         }
3435                 }
3436                 if ( empty( $errors ) ) {
3437                         return true;
3438                 }
3439                 return $errors;
3440         }
3441
3442         /**
3443          * Check if the requested move target is a valid file move target
3444          * @param Title $nt Target title
3445          * @return array List of errors
3446          */
3447         protected function validateFileMoveOperation( $nt ) {
3448                 global $wgUser;
3449
3450                 $errors = array();
3451
3452                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3453
3454                 $file = wfLocalFile( $this );
3455                 if ( $file->exists() ) {
3456                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3457                                 $errors[] = array( 'imageinvalidfilename' );
3458                         }
3459                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3460                                 $errors[] = array( 'imagetypemismatch' );
3461                         }
3462                 }
3463
3464                 if ( $nt->getNamespace() != NS_FILE ) {
3465                         $errors[] = array( 'imagenocrossnamespace' );
3466                         // From here we want to do checks on a file object, so if we can't
3467                         // create one, we must return.
3468                         return $errors;
3469                 }
3470
3471                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3472
3473                 $destFile = wfLocalFile( $nt );
3474                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3475                         $errors[] = array( 'file-exists-sharedrepo' );
3476                 }
3477
3478                 return $errors;
3479         }
3480
3481         /**
3482          * Move a title to a new location
3483          *
3484          * @param $nt Title the new title
3485          * @param $auth Bool indicates whether $wgUser's permissions
3486          *  should be checked
3487          * @param $reason String the reason for the move
3488          * @param $createRedirect Bool Whether to create a redirect from the old title to the new title.
3489          *  Ignored if the user doesn't have the suppressredirect right.
3490          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3491          */
3492         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3493                 global $wgUser;
3494                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3495                 if ( is_array( $err ) ) {
3496                         // Auto-block user's IP if the account was "hard" blocked
3497                         $wgUser->spreadAnyEditBlock();
3498                         return $err;
3499                 }
3500
3501                 // If it is a file, move it first.
3502                 // It is done before all other moving stuff is done because it's hard to revert.
3503                 $dbw = wfGetDB( DB_MASTER );
3504                 if ( $this->getNamespace() == NS_FILE ) {
3505                         $file = wfLocalFile( $this );
3506                         if ( $file->exists() ) {
3507                                 $status = $file->move( $nt );
3508                                 if ( !$status->isOk() ) {
3509                                         return $status->getErrorsArray();
3510                                 }
3511                         }
3512                         // Clear RepoGroup process cache
3513                         RepoGroup::singleton()->clearCache( $this );
3514                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3515                 }
3516
3517                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3518                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3519                 $protected = $this->isProtected();
3520
3521                 // Do the actual move
3522                 $err = $this->moveToInternal( $nt, $reason, $createRedirect );
3523                 if ( is_array( $err ) ) {
3524                         # @todo FIXME: What about the File we have already moved?
3525                         $dbw->rollback( __METHOD__ );
3526                         return $err;
3527                 }
3528
3529                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3530                 // cl_timestamp, which may disturb time-based lists on some sites.
3531                 $prefixes = $dbw->select(
3532                         'categorylinks',
3533                         array( 'cl_sortkey_prefix', 'cl_to' ),
3534                         array( 'cl_from' => $pageid ),
3535                         __METHOD__
3536                 );
3537                 foreach ( $prefixes as $prefixRow ) {
3538                         $prefix = $prefixRow->cl_sortkey_prefix;
3539                         $catTo = $prefixRow->cl_to;
3540                         $dbw->update( 'categorylinks',
3541                                 array(
3542                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3543                                                 $nt->getCategorySortkey( $prefix ) ),
3544                                         'cl_timestamp=cl_timestamp' ),
3545                                 array(
3546                                         'cl_from' => $pageid,
3547                                         'cl_to' => $catTo ),
3548                                 __METHOD__
3549                         );
3550                 }
3551
3552                 $redirid = $this->getArticleID();
3553
3554                 if ( $protected ) {
3555                         # Protect the redirect title as the title used to be...
3556                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3557                                 array(
3558                                         'pr_page'    => $redirid,
3559                                         'pr_type'    => 'pr_type',
3560                                         'pr_level'   => 'pr_level',
3561                                         'pr_cascade' => 'pr_cascade',
3562                                         'pr_user'    => 'pr_user',
3563                                         'pr_expiry'  => 'pr_expiry'
3564                                 ),
3565                                 array( 'pr_page' => $pageid ),
3566                                 __METHOD__,
3567                                 array( 'IGNORE' )
3568                         );
3569                         # Update the protection log
3570                         $log = new LogPage( 'protect' );
3571                         $comment = wfMsgForContent( 'prot_1movedto2', $this->getPrefixedText(), $nt->getPrefixedText() );
3572                         if ( $reason ) {
3573                                 $comment .= wfMsgForContent( 'colon-separator' ) . $reason;
3574                         }
3575                         // @todo FIXME: $params?
3576                         $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ) );
3577                 }
3578
3579                 # Update watchlists
3580                 $oldnamespace = $this->getNamespace() & ~1;
3581                 $newnamespace = $nt->getNamespace() & ~1;
3582                 $oldtitle = $this->getDBkey();
3583                 $newtitle = $nt->getDBkey();
3584
3585                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3586                         WatchedItem::duplicateEntries( $this, $nt );
3587                 }
3588
3589                 $dbw->commit( __METHOD__ );
3590
3591                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
3592                 return true;
3593         }
3594
3595         /**
3596          * Move page to a title which is either a redirect to the
3597          * source page or nonexistent
3598          *
3599          * @param $nt Title the page to move to, which should be a redirect or nonexistent
3600          * @param $reason String The reason for the move
3601          * @param $createRedirect Bool Whether to leave a redirect at the old title.  Ignored
3602          *   if the user doesn't have the suppressredirect right
3603          */
3604         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3605                 global $wgUser, $wgContLang;
3606
3607                 if ( $nt->exists() ) {
3608                         $moveOverRedirect = true;
3609                         $logType = 'move_redir';
3610                 } else {
3611                         $moveOverRedirect = false;
3612                         $logType = 'move';
3613                 }
3614
3615                 $redirectSuppressed = !$createRedirect && $wgUser->isAllowed( 'suppressredirect' );
3616
3617                 $logEntry = new ManualLogEntry( 'move', $logType );
3618                 $logEntry->setPerformer( $wgUser );
3619                 $logEntry->setTarget( $this );
3620                 $logEntry->setComment( $reason );
3621                 $logEntry->setParameters( array(
3622                         '4::target' => $nt->getPrefixedText(),
3623                         '5::noredir' => $redirectSuppressed ? '1': '0',
3624                 ) );
3625
3626                 $formatter = LogFormatter::newFromEntry( $logEntry );
3627                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3628                 $comment = $formatter->getPlainActionText();
3629                 if ( $reason ) {
3630                         $comment .= wfMsgForContent( 'colon-separator' ) . $reason;
3631                 }
3632                 # Truncate for whole multibyte characters.
3633                 $comment = $wgContLang->truncate( $comment, 255 );
3634
3635                 $oldid = $this->getArticleID();
3636
3637                 $dbw = wfGetDB( DB_MASTER );
3638
3639                 $newpage = WikiPage::factory( $nt );
3640
3641                 if ( $moveOverRedirect ) {
3642                         $newid = $nt->getArticleID();
3643
3644                         # Delete the old redirect. We don't save it to history since
3645                         # by definition if we've got here it's rather uninteresting.
3646                         # We have to remove it so that the next step doesn't trigger
3647                         # a conflict on the unique namespace+title index...
3648                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3649
3650                         $newpage->doDeleteUpdates( $newid );
3651                 }
3652
3653                 # Save a null revision in the page's history notifying of the move
3654                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
3655                 if ( !is_object( $nullRevision ) ) {
3656                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3657                 }
3658                 $nullRevId = $nullRevision->insertOn( $dbw );
3659
3660                 # Change the name of the target page:
3661                 $dbw->update( 'page',
3662                         /* SET */ array(
3663                                 'page_namespace' => $nt->getNamespace(),
3664                                 'page_title'     => $nt->getDBkey(),
3665                         ),
3666                         /* WHERE */ array( 'page_id' => $oldid ),
3667                         __METHOD__
3668                 );
3669
3670                 $this->resetArticleID( 0 );
3671                 $nt->resetArticleID( $oldid );
3672
3673                 $newpage->updateRevisionOn( $dbw, $nullRevision );
3674
3675                 wfRunHooks( 'NewRevisionFromEditComplete',
3676                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
3677
3678                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
3679
3680                 if ( !$moveOverRedirect ) {
3681                         WikiPage::onArticleCreate( $nt );
3682                 }
3683
3684                 # Recreate the redirect, this time in the other direction.
3685                 if ( $redirectSuppressed ) {
3686                         WikiPage::onArticleDelete( $this );
3687                 } else {
3688                         $mwRedir = MagicWord::get( 'redirect' );
3689                         $redirectText = $mwRedir->getSynonym( 0 ) . ' [[' . $nt->getPrefixedText() . "]]\n";
3690                         $redirectArticle = WikiPage::factory( $this );
3691                         $newid = $redirectArticle->insertOn( $dbw );
3692                         if ( $newid ) { // sanity
3693                                 $redirectRevision = new Revision( array(
3694                                         'page'    => $newid,
3695                                         'comment' => $comment,
3696                                         'text'    => $redirectText ) );
3697                                 $redirectRevision->insertOn( $dbw );
3698                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
3699
3700                                 wfRunHooks( 'NewRevisionFromEditComplete',
3701                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
3702
3703                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
3704                         }
3705                 }
3706
3707                 # Log the move
3708                 $logid = $logEntry->insert();
3709                 $logEntry->publish( $logid );
3710         }
3711
3712         /**
3713          * Move this page's subpages to be subpages of $nt
3714          *
3715          * @param $nt Title Move target
3716          * @param $auth bool Whether $wgUser's permissions should be checked
3717          * @param $reason string The reason for the move
3718          * @param $createRedirect bool Whether to create redirects from the old subpages to
3719          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3720          * @return mixed array with old page titles as keys, and strings (new page titles) or
3721          *     arrays (errors) as values, or an error array with numeric indices if no pages
3722          *     were moved
3723          */
3724         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3725                 global $wgMaximumMovedPages;
3726                 // Check permissions
3727                 if ( !$this->userCan( 'move-subpages' ) ) {
3728                         return array( 'cant-move-subpages' );
3729                 }
3730                 // Do the source and target namespaces support subpages?
3731                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3732                         return array( 'namespace-nosubpages',
3733                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3734                 }
3735                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3736                         return array( 'namespace-nosubpages',
3737                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3738                 }
3739
3740                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3741                 $retval = array();
3742                 $count = 0;
3743                 foreach ( $subpages as $oldSubpage ) {
3744                         $count++;
3745                         if ( $count > $wgMaximumMovedPages ) {
3746                                 $retval[$oldSubpage->getPrefixedTitle()] =
3747                                                 array( 'movepage-max-pages',
3748                                                         $wgMaximumMovedPages );
3749                                 break;
3750                         }
3751
3752                         // We don't know whether this function was called before
3753                         // or after moving the root page, so check both
3754                         // $this and $nt
3755                         if ( $oldSubpage->getArticleID() == $this->getArticleID() ||
3756                                         $oldSubpage->getArticleID() == $nt->getArticleID() )
3757                         {
3758                                 // When moving a page to a subpage of itself,
3759                                 // don't move it twice
3760                                 continue;
3761                         }
3762                         $newPageName = preg_replace(
3763                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3764                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3765                                         $oldSubpage->getDBkey() );
3766                         if ( $oldSubpage->isTalkPage() ) {
3767                                 $newNs = $nt->getTalkPage()->getNamespace();
3768                         } else {
3769                                 $newNs = $nt->getSubjectPage()->getNamespace();
3770                         }
3771                         # Bug 14385: we need makeTitleSafe because the new page names may
3772                         # be longer than 255 characters.
3773                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3774
3775                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3776                         if ( $success === true ) {
3777                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3778                         } else {
3779                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3780                         }
3781                 }
3782                 return $retval;
3783         }
3784
3785         /**
3786          * Checks if this page is just a one-rev redirect.
3787          * Adds lock, so don't use just for light purposes.
3788          *
3789          * @return Bool
3790          */
3791         public function isSingleRevRedirect() {
3792                 $dbw = wfGetDB( DB_MASTER );
3793                 # Is it a redirect?
3794                 $row = $dbw->selectRow( 'page',
3795                         array( 'page_is_redirect', 'page_latest', 'page_id' ),
3796                         $this->pageCond(),
3797                         __METHOD__,
3798                         array( 'FOR UPDATE' )
3799                 );
3800                 # Cache some fields we may want
3801                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3802                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3803                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3804                 if ( !$this->mRedirect ) {
3805                         return false;
3806                 }
3807                 # Does the article have a history?
3808                 $row = $dbw->selectField( array( 'page', 'revision' ),
3809                         'rev_id',
3810                         array( 'page_namespace' => $this->getNamespace(),
3811                                 'page_title' => $this->getDBkey(),
3812                                 'page_id=rev_page',
3813                                 'page_latest != rev_id'
3814                         ),
3815                         __METHOD__,
3816                         array( 'FOR UPDATE' )
3817                 );
3818                 # Return true if there was no history
3819                 return ( $row === false );
3820         }
3821
3822         /**
3823          * Checks if $this can be moved to a given Title
3824          * - Selects for update, so don't call it unless you mean business
3825          *
3826          * @param $nt Title the new title to check
3827          * @return Bool
3828          */
3829         public function isValidMoveTarget( $nt ) {
3830                 # Is it an existing file?
3831                 if ( $nt->getNamespace() == NS_FILE ) {
3832                         $file = wfLocalFile( $nt );
3833                         if ( $file->exists() ) {
3834                                 wfDebug( __METHOD__ . ": file exists\n" );
3835                                 return false;
3836                         }
3837                 }
3838                 # Is it a redirect with no history?
3839                 if ( !$nt->isSingleRevRedirect() ) {
3840                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3841                         return false;
3842                 }
3843                 # Get the article text
3844                 $rev = Revision::newFromTitle( $nt );
3845                 if( !is_object( $rev ) ){
3846                         return false;
3847                 }
3848                 $text = $rev->getText();
3849                 # Does the redirect point to the source?
3850                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3851                 $m = array();
3852                 if ( preg_match( "/\\[\\[\\s*([^\\]\\|]*)]]/", $text, $m ) ) {
3853                         $redirTitle = Title::newFromText( $m[1] );
3854                         if ( !is_object( $redirTitle ) ||
3855                                 ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3856                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) ) {
3857                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3858                                 return false;
3859                         }
3860                 } else {
3861                         # Fail safe
3862                         wfDebug( __METHOD__ . ": failsafe\n" );
3863                         return false;
3864                 }
3865                 return true;
3866         }
3867
3868         /**
3869          * Get categories to which this Title belongs and return an array of
3870          * categories' names.
3871          *
3872          * @return Array of parents in the form:
3873          *        $parent => $currentarticle
3874          */
3875         public function getParentCategories() {
3876                 global $wgContLang;
3877
3878                 $data = array();
3879
3880                 $titleKey = $this->getArticleID();
3881
3882                 if ( $titleKey === 0 ) {
3883                         return $data;
3884                 }
3885
3886                 $dbr = wfGetDB( DB_SLAVE );
3887
3888                 $res = $dbr->select( 'categorylinks', '*',
3889                         array(
3890                                 'cl_from' => $titleKey,
3891                         ),
3892                         __METHOD__,
3893                         array()
3894                 );
3895
3896                 if ( $dbr->numRows( $res ) > 0 ) {
3897                         foreach ( $res as $row ) {
3898                                 // $data[] = Title::newFromText($wgContLang->getNSText ( NS_CATEGORY ).':'.$row->cl_to);
3899                                 $data[$wgContLang->getNSText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3900                         }
3901                 }
3902                 return $data;
3903         }
3904
3905         /**
3906          * Get a tree of parent categories
3907          *
3908          * @param $children Array with the children in the keys, to check for circular refs
3909          * @return Array Tree of parent categories
3910          */
3911         public function getParentCategoryTree( $children = array() ) {
3912                 $stack = array();
3913                 $parents = $this->getParentCategories();
3914
3915                 if ( $parents ) {
3916                         foreach ( $parents as $parent => $current ) {
3917                                 if ( array_key_exists( $parent, $children ) ) {
3918                                         # Circular reference
3919                                         $stack[$parent] = array();
3920                                 } else {
3921                                         $nt = Title::newFromText( $parent );
3922                                         if ( $nt ) {
3923                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
3924                                         }
3925                                 }
3926                         }
3927                 }
3928
3929                 return $stack;
3930         }
3931
3932         /**
3933          * Get an associative array for selecting this title from
3934          * the "page" table
3935          *
3936          * @return Array suitable for the $where parameter of DB::select()
3937          */
3938         public function pageCond() {
3939                 if ( $this->mArticleID > 0 ) {
3940                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3941                         return array( 'page_id' => $this->mArticleID );
3942                 } else {
3943                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
3944                 }
3945         }
3946
3947         /**
3948          * Get the revision ID of the previous revision
3949          *
3950          * @param $revId Int Revision ID. Get the revision that was before this one.
3951          * @param $flags Int Title::GAID_FOR_UPDATE
3952          * @return Int|Bool Old revision ID, or FALSE if none exists
3953          */
3954         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3955                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3956                 return $db->selectField( 'revision', 'rev_id',
3957                         array(
3958                                 'rev_page' => $this->getArticleID( $flags ),
3959                                 'rev_id < ' . intval( $revId )
3960                         ),
3961                         __METHOD__,
3962                         array( 'ORDER BY' => 'rev_id DESC' )
3963                 );
3964         }
3965
3966         /**
3967          * Get the revision ID of the next revision
3968          *
3969          * @param $revId Int Revision ID. Get the revision that was after this one.
3970          * @param $flags Int Title::GAID_FOR_UPDATE
3971          * @return Int|Bool Next revision ID, or FALSE if none exists
3972          */
3973         public function getNextRevisionID( $revId, $flags = 0 ) {
3974                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3975                 return $db->selectField( 'revision', 'rev_id',
3976                         array(
3977                                 'rev_page' => $this->getArticleID( $flags ),
3978                                 'rev_id > ' . intval( $revId )
3979                         ),
3980                         __METHOD__,
3981                         array( 'ORDER BY' => 'rev_id' )
3982                 );
3983         }
3984
3985         /**
3986          * Get the first revision of the page
3987          *
3988          * @param $flags Int Title::GAID_FOR_UPDATE
3989          * @return Revision|Null if page doesn't exist
3990          */
3991         public function getFirstRevision( $flags = 0 ) {
3992                 $pageId = $this->getArticleID( $flags );
3993                 if ( $pageId ) {
3994                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3995                         $row = $db->selectRow( 'revision', '*',
3996                                 array( 'rev_page' => $pageId ),
3997                                 __METHOD__,
3998                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
3999                         );
4000                         if ( $row ) {
4001                                 return new Revision( $row );
4002                         }
4003                 }
4004                 return null;
4005         }
4006
4007         /**
4008          * Get the oldest revision timestamp of this page
4009          *
4010          * @param $flags Int Title::GAID_FOR_UPDATE
4011          * @return String: MW timestamp
4012          */
4013         public function getEarliestRevTime( $flags = 0 ) {
4014                 $rev = $this->getFirstRevision( $flags );
4015                 return $rev ? $rev->getTimestamp() : null;
4016         }
4017
4018         /**
4019          * Check if this is a new page
4020          *
4021          * @return bool
4022          */
4023         public function isNewPage() {
4024                 $dbr = wfGetDB( DB_SLAVE );
4025                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4026         }
4027
4028         /**
4029          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4030          *
4031          * @return bool
4032          */
4033         public function isBigDeletion() {
4034                 global $wgDeleteRevisionsLimit;
4035
4036                 if ( !$wgDeleteRevisionsLimit ) {
4037                         return false;
4038                 }
4039
4040                 $revCount = $this->estimateRevisionCount();
4041                 return $revCount > $wgDeleteRevisionsLimit;
4042         }
4043
4044         /**
4045          * Get the  approximate revision count of this page.
4046          *
4047          * @return int
4048          */
4049         public function estimateRevisionCount() {
4050                 if ( !$this->exists() ) {
4051                         return 0;
4052                 }
4053
4054                 if ( $this->mEstimateRevisions === null ) {
4055                         $dbr = wfGetDB( DB_SLAVE );
4056                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4057                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4058                 }
4059
4060                 return $this->mEstimateRevisions;
4061         }
4062
4063         /**
4064          * Get the number of revisions between the given revision.
4065          * Used for diffs and other things that really need it.
4066          *
4067          * @param $old int|Revision Old revision or rev ID (first before range)
4068          * @param $new int|Revision New revision or rev ID (first after range)
4069          * @return Int Number of revisions between these revisions.
4070          */
4071         public function countRevisionsBetween( $old, $new ) {
4072                 if ( !( $old instanceof Revision ) ) {
4073                         $old = Revision::newFromTitle( $this, (int)$old );
4074                 }
4075                 if ( !( $new instanceof Revision ) ) {
4076                         $new = Revision::newFromTitle( $this, (int)$new );
4077                 }
4078                 if ( !$old || !$new ) {
4079                         return 0; // nothing to compare
4080                 }
4081                 $dbr = wfGetDB( DB_SLAVE );
4082                 return (int)$dbr->selectField( 'revision', 'count(*)',
4083                         array(
4084                                 'rev_page' => $this->getArticleID(),
4085                                 'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4086                                 'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4087                         ),
4088                         __METHOD__
4089                 );
4090         }
4091
4092         /**
4093          * Get the number of authors between the given revision IDs.
4094          * Used for diffs and other things that really need it.
4095          *
4096          * @param $old int|Revision Old revision or rev ID (first before range)
4097          * @param $new int|Revision New revision or rev ID (first after range)
4098          * @param $limit Int Maximum number of authors
4099          * @return Int Number of revision authors between these revisions.
4100          */
4101         public function countAuthorsBetween( $old, $new, $limit ) {
4102                 if ( !( $old instanceof Revision ) ) {
4103                         $old = Revision::newFromTitle( $this, (int)$old );
4104                 }
4105                 if ( !( $new instanceof Revision ) ) {
4106                         $new = Revision::newFromTitle( $this, (int)$new );
4107                 }
4108                 if ( !$old || !$new ) {
4109                         return 0; // nothing to compare
4110                 }
4111                 $dbr = wfGetDB( DB_SLAVE );
4112                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4113                         array(
4114                                 'rev_page' => $this->getArticleID(),
4115                                 'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4116                                 'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4117                         ), __METHOD__,
4118                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4119                 );
4120                 return (int)$dbr->numRows( $res );
4121         }
4122
4123         /**
4124          * Compare with another title.
4125          *
4126          * @param $title Title
4127          * @return Bool
4128          */
4129         public function equals( Title $title ) {
4130                 // Note: === is necessary for proper matching of number-like titles.
4131                 return $this->getInterwiki() === $title->getInterwiki()
4132                         && $this->getNamespace() == $title->getNamespace()
4133                         && $this->getDBkey() === $title->getDBkey();
4134         }
4135
4136         /**
4137          * Check if this title is a subpage of another title
4138          *
4139          * @param $title Title
4140          * @return Bool
4141          */
4142         public function isSubpageOf( Title $title ) {
4143                 return $this->getInterwiki() === $title->getInterwiki()
4144                         && $this->getNamespace() == $title->getNamespace()
4145                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4146         }
4147
4148         /**
4149          * Check if page exists.  For historical reasons, this function simply
4150          * checks for the existence of the title in the page table, and will
4151          * thus return false for interwiki links, special pages and the like.
4152          * If you want to know if a title can be meaningfully viewed, you should
4153          * probably call the isKnown() method instead.
4154          *
4155          * @return Bool
4156          */
4157         public function exists() {
4158                 return $this->getArticleID() != 0;
4159         }
4160
4161         /**
4162          * Should links to this title be shown as potentially viewable (i.e. as
4163          * "bluelinks"), even if there's no record by this title in the page
4164          * table?
4165          *
4166          * This function is semi-deprecated for public use, as well as somewhat
4167          * misleadingly named.  You probably just want to call isKnown(), which
4168          * calls this function internally.
4169          *
4170          * (ISSUE: Most of these checks are cheap, but the file existence check
4171          * can potentially be quite expensive.  Including it here fixes a lot of
4172          * existing code, but we might want to add an optional parameter to skip
4173          * it and any other expensive checks.)
4174          *
4175          * @return Bool
4176          */
4177         public function isAlwaysKnown() {
4178                 $isKnown = null;
4179
4180                 /**
4181                  * Allows overriding default behaviour for determining if a page exists.
4182                  * If $isKnown is kept as null, regular checks happen. If it's
4183                  * a boolean, this value is returned by the isKnown method.
4184                  *
4185                  * @since 1.20
4186                  *
4187                  * @param Title $title
4188                  * @param boolean|null $isKnown
4189                  */
4190                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4191
4192                 if ( !is_null( $isKnown ) ) {
4193                         return $isKnown;
4194                 }
4195
4196                 if ( $this->mInterwiki != '' ) {
4197                         return true;  // any interwiki link might be viewable, for all we know
4198                 }
4199
4200                 switch( $this->mNamespace ) {
4201                         case NS_MEDIA:
4202                         case NS_FILE:
4203                                 // file exists, possibly in a foreign repo
4204                                 return (bool)wfFindFile( $this );
4205                         case NS_SPECIAL:
4206                                 // valid special page
4207                                 return SpecialPageFactory::exists( $this->getDBkey() );
4208                         case NS_MAIN:
4209                                 // selflink, possibly with fragment
4210                                 return $this->mDbkeyform == '';
4211                         case NS_MEDIAWIKI:
4212                                 // known system message
4213                                 return $this->hasSourceText() !== false;
4214                         default:
4215                                 return false;
4216                 }
4217         }
4218
4219         /**
4220          * Does this title refer to a page that can (or might) be meaningfully
4221          * viewed?  In particular, this function may be used to determine if
4222          * links to the title should be rendered as "bluelinks" (as opposed to
4223          * "redlinks" to non-existent pages).
4224          * Adding something else to this function will cause inconsistency
4225          * since LinkHolderArray calls isAlwaysKnown() and does its own
4226          * page existence check.
4227          *
4228          * @return Bool
4229          */
4230         public function isKnown() {
4231                 return $this->isAlwaysKnown() || $this->exists();
4232         }
4233
4234         /**
4235          * Does this page have source text?
4236          *
4237          * @return Boolean
4238          */
4239         public function hasSourceText() {
4240                 if ( $this->exists() ) {
4241                         return true;
4242                 }
4243
4244                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4245                         // If the page doesn't exist but is a known system message, default
4246                         // message content will be displayed, same for language subpages-
4247                         // Use always content language to avoid loading hundreds of languages
4248                         // to get the link color.
4249                         global $wgContLang;
4250                         list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4251                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4252                         return $message->exists();
4253                 }
4254
4255                 return false;
4256         }
4257
4258         /**
4259          * Get the default message text or false if the message doesn't exist
4260          *
4261          * @return String or false
4262          */
4263         public function getDefaultMessageText() {
4264                 global $wgContLang;
4265
4266                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4267                         return false;
4268                 }
4269
4270                 list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4271                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4272
4273                 if ( $message->exists() ) {
4274                         return $message->plain();
4275                 } else {
4276                         return false;
4277                 }
4278         }
4279
4280         /**
4281          * Updates page_touched for this page; called from LinksUpdate.php
4282          *
4283          * @return Bool true if the update succeded
4284          */
4285         public function invalidateCache() {
4286                 if ( wfReadOnly() ) {
4287                         return false;
4288                 }
4289                 $dbw = wfGetDB( DB_MASTER );
4290                 $success = $dbw->update(
4291                         'page',
4292                         array( 'page_touched' => $dbw->timestamp() ),
4293                         $this->pageCond(),
4294                         __METHOD__
4295                 );
4296                 HTMLFileCache::clearFileCache( $this );
4297                 return $success;
4298         }
4299
4300         /**
4301          * Update page_touched timestamps and send squid purge messages for
4302          * pages linking to this title. May be sent to the job queue depending
4303          * on the number of links. Typically called on create and delete.
4304          */
4305         public function touchLinks() {
4306                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4307                 $u->doUpdate();
4308
4309                 if ( $this->getNamespace() == NS_CATEGORY ) {
4310                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4311                         $u->doUpdate();
4312                 }
4313         }
4314
4315         /**
4316          * Get the last touched timestamp
4317          *
4318          * @param $db DatabaseBase: optional db
4319          * @return String last-touched timestamp
4320          */
4321         public function getTouched( $db = null ) {
4322                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
4323                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4324                 return $touched;
4325         }
4326
4327         /**
4328          * Get the timestamp when this page was updated since the user last saw it.
4329          *
4330          * @param $user User
4331          * @return String|Null
4332          */
4333         public function getNotificationTimestamp( $user = null ) {
4334                 global $wgUser, $wgShowUpdatedMarker;
4335                 // Assume current user if none given
4336                 if ( !$user ) {
4337                         $user = $wgUser;
4338                 }
4339                 // Check cache first
4340                 $uid = $user->getId();
4341                 // avoid isset here, as it'll return false for null entries
4342                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4343                         return $this->mNotificationTimestamp[$uid];
4344                 }
4345                 if ( !$uid || !$wgShowUpdatedMarker ) {
4346                         return $this->mNotificationTimestamp[$uid] = false;
4347                 }
4348                 // Don't cache too much!
4349                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4350                         $this->mNotificationTimestamp = array();
4351                 }
4352                 $dbr = wfGetDB( DB_SLAVE );
4353                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4354                         'wl_notificationtimestamp',
4355                         array( 'wl_namespace' => $this->getNamespace(),
4356                                 'wl_title' => $this->getDBkey(),
4357                                 'wl_user' => $user->getId()
4358                         ),
4359                         __METHOD__
4360                 );
4361                 return $this->mNotificationTimestamp[$uid];
4362         }
4363
4364         /**
4365          * Generate strings used for xml 'id' names in monobook tabs
4366          *
4367          * @param $prepend string defaults to 'nstab-'
4368          * @return String XML 'id' name
4369          */
4370         public function getNamespaceKey( $prepend = 'nstab-' ) {
4371                 global $wgContLang;
4372                 // Gets the subject namespace if this title
4373                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4374                 // Checks if cononical namespace name exists for namespace
4375                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4376                         // Uses canonical namespace name
4377                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4378                 } else {
4379                         // Uses text of namespace
4380                         $namespaceKey = $this->getSubjectNsText();
4381                 }
4382                 // Makes namespace key lowercase
4383                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4384                 // Uses main
4385                 if ( $namespaceKey == '' ) {
4386                         $namespaceKey = 'main';
4387                 }
4388                 // Changes file to image for backwards compatibility
4389                 if ( $namespaceKey == 'file' ) {
4390                         $namespaceKey = 'image';
4391                 }
4392                 return $prepend . $namespaceKey;
4393         }
4394
4395         /**
4396          * Get all extant redirects to this Title
4397          *
4398          * @param $ns Int|Null Single namespace to consider; NULL to consider all namespaces
4399          * @return Array of Title redirects to this title
4400          */
4401         public function getRedirectsHere( $ns = null ) {
4402                 $redirs = array();
4403
4404                 $dbr = wfGetDB( DB_SLAVE );
4405                 $where = array(
4406                         'rd_namespace' => $this->getNamespace(),
4407                         'rd_title' => $this->getDBkey(),
4408                         'rd_from = page_id'
4409                 );
4410                 if ( !is_null( $ns ) ) {
4411                         $where['page_namespace'] = $ns;
4412                 }
4413
4414                 $res = $dbr->select(
4415                         array( 'redirect', 'page' ),
4416                         array( 'page_namespace', 'page_title' ),
4417                         $where,
4418                         __METHOD__
4419                 );
4420
4421                 foreach ( $res as $row ) {
4422                         $redirs[] = self::newFromRow( $row );
4423                 }
4424                 return $redirs;
4425         }
4426
4427         /**
4428          * Check if this Title is a valid redirect target
4429          *
4430          * @return Bool
4431          */
4432         public function isValidRedirectTarget() {
4433                 global $wgInvalidRedirectTargets;
4434
4435                 // invalid redirect targets are stored in a global array, but explicity disallow Userlogout here
4436                 if ( $this->isSpecial( 'Userlogout' ) ) {
4437                         return false;
4438                 }
4439
4440                 foreach ( $wgInvalidRedirectTargets as $target ) {
4441                         if ( $this->isSpecial( $target ) ) {
4442                                 return false;
4443                         }
4444                 }
4445
4446                 return true;
4447         }
4448
4449         /**
4450          * Get a backlink cache object
4451          *
4452          * @return BacklinkCache
4453          */
4454         function getBacklinkCache() {
4455                 if ( is_null( $this->mBacklinkCache ) ) {
4456                         $this->mBacklinkCache = new BacklinkCache( $this );
4457                 }
4458                 return $this->mBacklinkCache;
4459         }
4460
4461         /**
4462          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4463          *
4464          * @return Boolean
4465          */
4466         public function canUseNoindex() {
4467                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4468
4469                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4470                         ? $wgContentNamespaces
4471                         : $wgExemptFromUserRobotsControl;
4472
4473                 return !in_array( $this->mNamespace, $bannedNamespaces );
4474
4475         }
4476
4477         /**
4478          * Returns the raw sort key to be used for categories, with the specified
4479          * prefix.  This will be fed to Collation::getSortKey() to get a
4480          * binary sortkey that can be used for actual sorting.
4481          *
4482          * @param $prefix string The prefix to be used, specified using
4483          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4484          *   prefix.
4485          * @return string
4486          */
4487         public function getCategorySortkey( $prefix = '' ) {
4488                 $unprefixed = $this->getText();
4489
4490                 // Anything that uses this hook should only depend
4491                 // on the Title object passed in, and should probably
4492                 // tell the users to run updateCollations.php --force
4493                 // in order to re-sort existing category relations.
4494                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4495                 if ( $prefix !== '' ) {
4496                         # Separate with a line feed, so the unprefixed part is only used as
4497                         # a tiebreaker when two pages have the exact same prefix.
4498                         # In UCA, tab is the only character that can sort above LF
4499                         # so we strip both of them from the original prefix.
4500                         $prefix = strtr( $prefix, "\n\t", '  ' );
4501                         return "$prefix\n$unprefixed";
4502                 }
4503                 return $unprefixed;
4504         }
4505
4506         /**
4507          * Get the language in which the content of this page is written.
4508          * Defaults to $wgContLang, but in certain cases it can be e.g.
4509          * $wgLang (such as special pages, which are in the user language).
4510          *
4511          * @since 1.18
4512          * @return object Language
4513          */
4514         public function getPageLanguage() {
4515                 global $wgLang;
4516                 if ( $this->isSpecialPage() ) {
4517                         // special pages are in the user language
4518                         return $wgLang;
4519                 } elseif ( $this->isCssOrJsPage() || $this->isCssJsSubpage() ) {
4520                         // css/js should always be LTR and is, in fact, English
4521                         return wfGetLangObj( 'en' );
4522                 } elseif ( $this->getNamespace() == NS_MEDIAWIKI ) {
4523                         // Parse mediawiki messages with correct target language
4524                         list( /* $unused */, $lang ) = MessageCache::singleton()->figureMessage( $this->getText() );
4525                         return wfGetLangObj( $lang );
4526                 }
4527                 global $wgContLang;
4528                 // If nothing special, it should be in the wiki content language
4529                 $pageLang = $wgContLang;
4530                 // Hook at the end because we don't want to override the above stuff
4531                 wfRunHooks( 'PageContentLanguage', array( $this, &$pageLang, $wgLang ) );
4532                 return wfGetLangObj( $pageLang );
4533         }
4534 }