includes/Title.php

   1 <?php
   2 /**
   3  * See title.txt
   4  * @file
   5  */
   6
   7 /**
   8  * @todo:  determine if it is really necessary to load this.  Appears to be left over from pre-autoloader versions, and
   9  *   is only really needed to provide access to constant UTF8_REPLACEMENT, which actually resides in UtfNormalDefines.php
  10  *   and is loaded by UtfNormalUtil.php, which is loaded by UtfNormal.php.
  11  */
  12 if ( !class_exists( 'UtfNormal' ) ) {
  13         require_once( dirname( __FILE__ ) . '/normal/UtfNormal.php' );
  14 }
  15
  16 /**
  17  * @deprecated This used to be a define, but was moved to
  18  * Title::GAID_FOR_UPDATE in 1.17. This will probably be removed in 1.18
  19  */
  20 define( 'GAID_FOR_UPDATE', Title::GAID_FOR_UPDATE );
  21
  22 /**
  23  * Represents a title within MediaWiki.
  24  * Optionally may contain an interwiki designation or namespace.
  25  * @note This class can fetch various kinds of data from the database;
  26  *       however, it does so inefficiently.
  27  *
  28  * @internal documentation reviewed 15 Mar 2010
  29  */
  30 class Title {
  31         /** @name Static cache variables */
  32         // @{
  33         static private $titleCache = array();
  34         // @}
  35
  36         /**
  37          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  38          * commonly used titles. On a batch operation this can become a memory leak
  39          * if not bounded. After hitting this many titles reset the cache.
  40          */
  41         const CACHE_MAX = 1000;
  42
  43         /**
  44          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  45          * to use the master DB
  46          */
  47         const GAID_FOR_UPDATE = 1;
  48
  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         var $mRestrictions = array();     // /< Array of groups allowed to edit this article
  67         var $mOldRestrictions = false;
  68         var $mCascadeRestriction;         ///< Cascade restrictions on this page to included templates and images?
  69         var $mCascadingRestrictions;      // Caching the results of getCascadeProtectionSources
  70         var $mRestrictionsExpiry = array(); ///< When do the restrictions on this page expire?
  71         var $mHasCascadingRestrictions;   ///< Are cascading restrictions in effect on this page?
  72         var $mCascadeSources;             ///< Where are the cascading restrictions coming from on this page?
  73         var $mRestrictionsLoaded = false; ///< Boolean for initialisation on demand
  74         var $mPrefixedText;               ///< Text form including namespace/interwiki, initialised on demand
  75         var $mTitleProtection;            ///< Cached value for getTitleProtection (create protection)
  76         # Don't change the following default, NS_MAIN is hardcoded in several
  77         # places.  See bug 696.
  78         var $mDefaultNamespace = NS_MAIN; // /< Namespace index when there is no namespace
  79                                                                           # Zero except in {{transclusion}} tags
  80         var $mWatched = null;             // /< Is $wgUser watching this page? null if unfilled, accessed through userIsWatching()
  81         var $mLength = -1;                // /< The page length, 0 for special pages
  82         var $mRedirect = null;            // /< Is the article at this title a redirect?
  83         var $mNotificationTimestamp = array(); // /< Associative array of user ID -> timestamp/false
  84         var $mBacklinkCache = null;       // /< Cache of links to this title
  85         // @}
  86
  87
  88         /**
  89          * Constructor
  90          * @private
  91          */
  92         /* private */ 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
 256                 $t->mArticleID = isset( $row->page_id ) ? intval( $row->page_id ) : -1;
 257                 $t->mLength = isset( $row->page_len ) ? intval( $row->page_len ) : -1;
 258                 $t->mRedirect = isset( $row->page_is_redirect ) ? (bool)$row->page_is_redirect : null;
 259                 $t->mLatestID = isset( $row->page_latest ) ? intval( $row->page_latest ) : false;
 260
 261                 return $t;
 262         }
 263
 264         /**
 265          * Create a new Title from a namespace index and a DB key.
 266          * It's assumed that $ns and $title are *valid*, for instance when
 267          * they came directly from the database or a special page name.
 268          * For convenience, spaces are converted to underscores so that
 269          * eg user_text fields can be used directly.
 270          *
 271          * @param $ns Int the namespace of the article
 272          * @param $title String the unprefixed database key form
 273          * @param $fragment String the link fragment (after the "#")
 274          * @param $interwiki String the interwiki prefix
 275          * @return Title the new object
 276          */
 277         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 278                 $t = new Title();
 279                 $t->mInterwiki = $interwiki;
 280                 $t->mFragment = $fragment;
 281                 $t->mNamespace = $ns = intval( $ns );
 282                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 283                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 284                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 285                 $t->mTextform = str_replace( '_', ' ', $title );
 286                 return $t;
 287         }
 288
 289         /**
 290          * Create a new Title from a namespace index and a DB key.
 291          * The parameters will be checked for validity, which is a bit slower
 292          * than makeTitle() but safer for user-provided data.
 293          *
 294          * @param $ns Int the namespace of the article
 295          * @param $title String database key form
 296          * @param $fragment String the link fragment (after the "#")
 297          * @param $interwiki String interwiki prefix
 298          * @return Title the new object, or NULL on an error
 299          */
 300         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 301                 $t = new Title();
 302                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 303                 if ( $t->secureAndSplit() ) {
 304                         return $t;
 305                 } else {
 306                         return null;
 307                 }
 308         }
 309
 310         /**
 311          * Create a new Title for the Main Page
 312          *
 313          * @return Title the new object
 314          */
 315         public static function newMainPage() {
 316                 $title = Title::newFromText( wfMsgForContent( 'mainpage' ) );
 317                 // Don't give fatal errors if the message is broken
 318                 if ( !$title ) {
 319                         $title = Title::newFromText( 'Main Page' );
 320                 }
 321                 return $title;
 322         }
 323
 324         /**
 325          * Extract a redirect destination from a string and return the
 326          * Title, or null if the text doesn't contain a valid redirect
 327          * This will only return the very next target, useful for
 328          * the redirect table and other checks that don't need full recursion
 329          *
 330          * @param $text String: Text with possible redirect
 331          * @return Title: The corresponding Title
 332          */
 333         public static function newFromRedirect( $text ) {
 334                 return self::newFromRedirectInternal( $text );
 335         }
 336
 337         /**
 338          * Extract a redirect destination from a string and return the
 339          * Title, or null if the text doesn't contain a valid redirect
 340          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 341          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 342          *
 343          * @param $text String Text with possible redirect
 344          * @return Title
 345          */
 346         public static function newFromRedirectRecurse( $text ) {
 347                 $titles = self::newFromRedirectArray( $text );
 348                 return $titles ? array_pop( $titles ) : null;
 349         }
 350
 351         /**
 352          * Extract a redirect destination from a string and return an
 353          * array of Titles, or null if the text doesn't contain a valid redirect
 354          * The last element in the array is the final destination after all redirects
 355          * have been resolved (up to $wgMaxRedirects times)
 356          *
 357          * @param $text String Text with possible redirect
 358          * @return Array of Titles, with the destination last
 359          */
 360         public static function newFromRedirectArray( $text ) {
 361                 global $wgMaxRedirects;
 362                 $title = self::newFromRedirectInternal( $text );
 363                 if ( is_null( $title ) ) {
 364                         return null;
 365                 }
 366                 // recursive check to follow double redirects
 367                 $recurse = $wgMaxRedirects;
 368                 $titles = array( $title );
 369                 while ( --$recurse > 0 ) {
 370                         if ( $title->isRedirect() ) {
 371                                 $article = new Article( $title, 0 );
 372                                 $newtitle = $article->getRedirectTarget();
 373                         } else {
 374                                 break;
 375                         }
 376                         // Redirects to some special pages are not permitted
 377                         if ( $newtitle instanceOf Title && $newtitle->isValidRedirectTarget() ) {
 378                                 // the new title passes the checks, so make that our current title so that further recursion can be checked
 379                                 $title = $newtitle;
 380                                 $titles[] = $newtitle;
 381                         } else {
 382                                 break;
 383                         }
 384                 }
 385                 return $titles;
 386         }
 387
 388         /**
 389          * Really extract the redirect destination
 390          * Do not call this function directly, use one of the newFromRedirect* functions above
 391          *
 392          * @param $text String Text with possible redirect
 393          * @return Title
 394          */
 395         protected static function newFromRedirectInternal( $text ) {
 396                 global $wgMaxRedirects;
 397                 if ( $wgMaxRedirects < 1 ) {
 398                         //redirects are disabled, so quit early
 399                         return null;
 400                 }
 401                 $redir = MagicWord::get( 'redirect' );
 402                 $text = trim( $text );
 403                 if ( $redir->matchStartAndRemove( $text ) ) {
 404                         // Extract the first link and see if it's usable
 405                         // Ensure that it really does come directly after #REDIRECT
 406                         // Some older redirects included a colon, so don't freak about that!
 407                         $m = array();
 408                         if ( preg_match( '!^\s*:?\s*\[{2}(.*?)(?:\|.*?)?\]{2}!', $text, $m ) ) {
 409                                 // Strip preceding colon used to "escape" categories, etc.
 410                                 // and URL-decode links
 411                                 if ( strpos( $m[1], '%' ) !== false ) {
 412                                         // Match behavior of inline link parsing here;
 413                                         $m[1] = rawurldecode( ltrim( $m[1], ':' ) );
 414                                 }
 415                                 $title = Title::newFromText( $m[1] );
 416                                 // If the title is a redirect to bad special pages or is invalid, return null
 417                                 if ( !$title instanceof Title || !$title->isValidRedirectTarget() ) {
 418                                         return null;
 419                                 }
 420                                 return $title;
 421                         }
 422                 }
 423                 return null;
 424         }
 425
 426 # ----------------------------------------------------------------------------
 427 #       Static functions
 428 # ----------------------------------------------------------------------------
 429
 430         /**
 431          * Get the prefixed DB key associated with an ID
 432          *
 433          * @param $id Int the page_id of the article
 434          * @return Title an object representing the article, or NULL if no such article was found
 435          */
 436         public static function nameOf( $id ) {
 437                 $dbr = wfGetDB( DB_SLAVE );
 438
 439                 $s = $dbr->selectRow(
 440                         'page',
 441                         array( 'page_namespace', 'page_title' ),
 442                         array( 'page_id' => $id ),
 443                         __METHOD__
 444                 );
 445                 if ( $s === false ) {
 446                         return null;
 447                 }
 448
 449                 $n = self::makeName( $s->page_namespace, $s->page_title );
 450                 return $n;
 451         }
 452
 453         /**
 454          * Get a regex character class describing the legal characters in a link
 455          *
 456          * @return String the list of characters, not delimited
 457          */
 458         public static function legalChars() {
 459                 global $wgLegalTitleChars;
 460                 return $wgLegalTitleChars;
 461         }
 462
 463         /**
 464          * Get a string representation of a title suitable for
 465          * including in a search index
 466          *
 467          * @param $ns Int a namespace index
 468          * @param $title String text-form main part
 469          * @return String a stripped-down title string ready for the search index
 470          */
 471         public static function indexTitle( $ns, $title ) {
 472                 global $wgContLang;
 473
 474                 $lc = SearchEngine::legalSearchChars() . '&#;';
 475                 $t = $wgContLang->normalizeForSearch( $title );
 476                 $t = preg_replace( "/[^{$lc}]+/", ' ', $t );
 477                 $t = $wgContLang->lc( $t );
 478
 479                 # Handle 's, s'
 480                 $t = preg_replace( "/([{$lc}]+)'s( |$)/", "\\1 \\1's ", $t );
 481                 $t = preg_replace( "/([{$lc}]+)s'( |$)/", "\\1s ", $t );
 482
 483                 $t = preg_replace( "/\\s+/", ' ', $t );
 484
 485                 if ( $ns == NS_FILE ) {
 486                         $t = preg_replace( "/ (png|gif|jpg|jpeg|ogg)$/", "", $t );
 487                 }
 488                 return trim( $t );
 489         }
 490
 491         /**
 492          * Make a prefixed DB key from a DB key and a namespace index
 493          *
 494          * @param $ns Int numerical representation of the namespace
 495          * @param $title String the DB key form the title
 496          * @param $fragment String The link fragment (after the "#")
 497          * @param $interwiki String The interwiki prefix
 498          * @return String the prefixed form of the title
 499          */
 500         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 501                 global $wgContLang;
 502
 503                 $namespace = $wgContLang->getNsText( $ns );
 504                 $name = $namespace == '' ? $title : "$namespace:$title";
 505                 if ( strval( $interwiki ) != '' ) {
 506                         $name = "$interwiki:$name";
 507                 }
 508                 if ( strval( $fragment ) != '' ) {
 509                         $name .= '#' . $fragment;
 510                 }
 511                 return $name;
 512         }
 513
 514         /**
 515          * Determine whether the object refers to a page within
 516          * this project.
 517          *
 518          * @return Bool TRUE if this is an in-project interwiki link or a wikilink, FALSE otherwise
 519          */
 520         public function isLocal() {
 521                 if ( $this->mInterwiki != '' ) {
 522                         return Interwiki::fetch( $this->mInterwiki )->isLocal();
 523                 } else {
 524                         return true;
 525                 }
 526         }
 527
 528         /**
 529          * Determine whether the object refers to a page within
 530          * this project and is transcludable.
 531          *
 532          * @return Bool TRUE if this is transcludable
 533          */
 534         public function isTrans() {
 535                 if ( $this->mInterwiki == '' ) {
 536                         return false;
 537                 }
 538
 539                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 540         }
 541
 542         /**
 543          * Returns the DB name of the distant wiki which owns the object.
 544          *
 545          * @return String the DB name
 546          */
 547         public function getTransWikiID() {
 548                 if ( $this->mInterwiki == '' ) {
 549                         return false;
 550                 }
 551
 552                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 553         }
 554
 555         /**
 556          * Escape a text fragment, say from a link, for a URL
 557          *
 558          * @param $fragment string containing a URL or link fragment (after the "#")
 559          * @return String: escaped string
 560          */
 561         static function escapeFragmentForURL( $fragment ) {
 562                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 563                 # fragments appear not to work in IE (at least up to 7) or in at least
 564                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 565                 # to care if they aren't encoded.
 566                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 567         }
 568
 569 # ----------------------------------------------------------------------------
 570 #       Other stuff
 571 # ----------------------------------------------------------------------------
 572
 573         /** Simple accessors */
 574         /**
 575          * Get the text form (spaces not underscores) of the main part
 576          *
 577          * @return String Main part of the title
 578          */
 579         public function getText() { return $this->mTextform; }
 580
 581         /**
 582          * Get the URL-encoded form of the main part
 583          *
 584          * @return String Main part of the title, URL-encoded
 585          */
 586         public function getPartialURL() { return $this->mUrlform; }
 587
 588         /**
 589          * Get the main part with underscores
 590          *
 591          * @return String: Main part of the title, with underscores
 592          */
 593         public function getDBkey() { return $this->mDbkeyform; }
 594
 595         /**
 596          * Get the namespace index, i.e. one of the NS_xxxx constants.
 597          *
 598          * @return Integer: Namespace index
 599          */
 600         public function getNamespace() { return $this->mNamespace; }
 601
 602         /**
 603          * Get the namespace text
 604          *
 605          * @return String: Namespace text
 606          */
 607         public function getNsText() {
 608                 global $wgContLang;
 609
 610                 if ( $this->mInterwiki != '' ) {
 611                         // This probably shouldn't even happen. ohh man, oh yuck.
 612                         // But for interwiki transclusion it sometimes does.
 613                         // Shit. Shit shit shit.
 614                         //
 615                         // Use the canonical namespaces if possible to try to
 616                         // resolve a foreign namespace.
 617                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 618                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 619                         }
 620                 }
 621
 622                 if ( $wgContLang->needsGenderDistinction() &&
 623                                 MWNamespace::hasGenderDistinction( $this->mNamespace ) ) {
 624                         $gender = GenderCache::singleton()->getGenderOf( $this->getText(), __METHOD__ );
 625                         return $wgContLang->getGenderNsText( $this->mNamespace, $gender );
 626                 }
 627
 628                 return $wgContLang->getNsText( $this->mNamespace );
 629         }
 630
 631         /**
 632          * Get the DB key with the initial letter case as specified by the user
 633          *
 634          * @return String DB key
 635          */
 636         function getUserCaseDBKey() {
 637                 return $this->mUserCaseDBKey;
 638         }
 639
 640         /**
 641          * Get the namespace text of the subject (rather than talk) page
 642          *
 643          * @return String Namespace text
 644          */
 645         public function getSubjectNsText() {
 646                 global $wgContLang;
 647                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 648         }
 649
 650         /**
 651          * Get the namespace text of the talk page
 652          *
 653          * @return String Namespace text
 654          */
 655         public function getTalkNsText() {
 656                 global $wgContLang;
 657                 return( $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) ) );
 658         }
 659
 660         /**
 661          * Could this title have a corresponding talk page?
 662          *
 663          * @return Bool TRUE or FALSE
 664          */
 665         public function canTalk() {
 666                 return( MWNamespace::canTalk( $this->mNamespace ) );
 667         }
 668
 669         /**
 670          * Get the interwiki prefix (or null string)
 671          *
 672          * @return String Interwiki prefix
 673          */
 674         public function getInterwiki() { return $this->mInterwiki; }
 675
 676         /**
 677          * Get the Title fragment (i.e.\ the bit after the #) in text form
 678          *
 679          * @return String Title fragment
 680          */
 681         public function getFragment() { return $this->mFragment; }
 682
 683         /**
 684          * Get the fragment in URL form, including the "#" character if there is one
 685          * @return String Fragment in URL form
 686          */
 687         public function getFragmentForURL() {
 688                 if ( $this->mFragment == '' ) {
 689                         return '';
 690                 } else {
 691                         return '#' . Title::escapeFragmentForURL( $this->mFragment );
 692                 }
 693         }
 694
 695         /**
 696          * Get the default namespace index, for when there is no namespace
 697          *
 698          * @return Int Default namespace index
 699          */
 700         public function getDefaultNamespace() { return $this->mDefaultNamespace; }
 701
 702         /**
 703          * Get title for search index
 704          *
 705          * @return String a stripped-down title string ready for the
 706          *  search index
 707          */
 708         public function getIndexTitle() {
 709                 return Title::indexTitle( $this->mNamespace, $this->mTextform );
 710         }
 711
 712         /**
 713          * Get the prefixed database key form
 714          *
 715          * @return String the prefixed title, with underscores and
 716          *  any interwiki and namespace prefixes
 717          */
 718         public function getPrefixedDBkey() {
 719                 $s = $this->prefix( $this->mDbkeyform );
 720                 $s = str_replace( ' ', '_', $s );
 721                 return $s;
 722         }
 723
 724         /**
 725          * Get the prefixed title with spaces.
 726          * This is the form usually used for display
 727          *
 728          * @return String the prefixed title, with spaces
 729          */
 730         public function getPrefixedText() {
 731                 if ( empty( $this->mPrefixedText ) ) { // FIXME: bad usage of empty() ?
 732                         $s = $this->prefix( $this->mTextform );
 733                         $s = str_replace( '_', ' ', $s );
 734                         $this->mPrefixedText = $s;
 735                 }
 736                 return $this->mPrefixedText;
 737         }
 738
 739         /**
 740          * Get the prefixed title with spaces, plus any fragment
 741          * (part beginning with '#')
 742          *
 743          * @return String the prefixed title, with spaces and the fragment, including '#'
 744          */
 745         public function getFullText() {
 746                 $text = $this->getPrefixedText();
 747                 if ( $this->mFragment != '' ) {
 748                         $text .= '#' . $this->mFragment;
 749                 }
 750                 return $text;
 751         }
 752
 753         /**
 754          * Get the base name, i.e. the leftmost parts before the /
 755          *
 756          * @return String Base name
 757          */
 758         public function getBaseText() {
 759                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
 760                         return $this->getText();
 761                 }
 762
 763                 $parts = explode( '/', $this->getText() );
 764                 # Don't discard the real title if there's no subpage involved
 765                 if ( count( $parts ) > 1 ) {
 766                         unset( $parts[count( $parts ) - 1] );
 767                 }
 768                 return implode( '/', $parts );
 769         }
 770
 771         /**
 772          * Get the lowest-level subpage name, i.e. the rightmost part after /
 773          *
 774          * @return String Subpage name
 775          */
 776         public function getSubpageText() {
 777                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
 778                         return( $this->mTextform );
 779                 }
 780                 $parts = explode( '/', $this->mTextform );
 781                 return( $parts[count( $parts ) - 1] );
 782         }
 783
 784         /**
 785          * Get a URL-encoded form of the subpage text
 786          *
 787          * @return String URL-encoded subpage name
 788          */
 789         public function getSubpageUrlForm() {
 790                 $text = $this->getSubpageText();
 791                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
 792                 return( $text );
 793         }
 794
 795         /**
 796          * Get a URL-encoded title (not an actual URL) including interwiki
 797          *
 798          * @return String the URL-encoded form
 799          */
 800         public function getPrefixedURL() {
 801                 $s = $this->prefix( $this->mDbkeyform );
 802                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
 803                 return $s;
 804         }
 805
 806         /**
 807          * Get a real URL referring to this title, with interwiki link and
 808          * fragment
 809          *
 810          * @param $query \twotypes{\string,\array} an optional query string, not used for interwiki
 811          *   links. Can be specified as an associative array as well, e.g.,
 812          *   array( 'action' => 'edit' ) (keys and values will be URL-escaped).
 813          * @param $variant String language variant of url (for sr, zh..)
 814          * @return String the URL
 815          */
 816         public function getFullURL( $query = '', $variant = false ) {
 817                 global $wgServer, $wgRequest;
 818
 819                 if ( is_array( $query ) ) {
 820                         $query = wfArrayToCGI( $query );
 821                 }
 822
 823                 $interwiki = Interwiki::fetch( $this->mInterwiki );
 824                 if ( !$interwiki ) {
 825                         $url = $this->getLocalURL( $query, $variant );
 826
 827                         // Ugly quick hack to avoid duplicate prefixes (bug 4571 etc)
 828                         // Correct fix would be to move the prepending elsewhere.
 829                         if ( $wgRequest->getVal( 'action' ) != 'render' ) {
 830                                 $url = $wgServer . $url;
 831                         }
 832                 } else {
 833                         $baseUrl = $interwiki->getURL();
 834
 835                         $namespace = wfUrlencode( $this->getNsText() );
 836                         if ( $namespace != '' ) {
 837                                 # Can this actually happen? Interwikis shouldn't be parsed.
 838                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
 839                                 $namespace .= ':';
 840                         }
 841                         $url = str_replace( '$1', $namespace . $this->mUrlform, $baseUrl );
 842                         $url = wfAppendQuery( $url, $query );
 843                 }
 844
 845                 # Finally, add the fragment.
 846                 $url .= $this->getFragmentForURL();
 847
 848                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
 849                 return $url;
 850         }
 851
 852         /**
 853          * Get a URL with no fragment or server name.  If this page is generated
 854          * with action=render, $wgServer is prepended.
 855          *
 856          * @param $query Mixed: an optional query string; if not specified,
 857          *   $wgArticlePath will be used.  Can be specified as an associative array
 858          *   as well, e.g., array( 'action' => 'edit' ) (keys and values will be
 859          *   URL-escaped).
 860          * @param $variant String language variant of url (for sr, zh..)
 861          * @return String the URL
 862          */
 863         public function getLocalURL( $query = '', $variant = false ) {
 864                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
 865                 global $wgVariantArticlePath, $wgContLang;
 866
 867                 if ( is_array( $query ) ) {
 868                         $query = wfArrayToCGI( $query );
 869                 }
 870
 871                 if ( $this->isExternal() ) {
 872                         $url = $this->getFullURL();
 873                         if ( $query ) {
 874                                 // This is currently only used for edit section links in the
 875                                 // context of interwiki transclusion. In theory we should
 876                                 // append the query to the end of any existing query string,
 877                                 // but interwiki transclusion is already broken in that case.
 878                                 $url .= "?$query";
 879                         }
 880                 } else {
 881                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
 882                         if ( $query == '' ) {
 883                                 if ( $variant != false && $wgContLang->hasVariants() ) {
 884                                         if ( !$wgVariantArticlePath ) {
 885                                                 $variantArticlePath =  "$wgScript?title=$1&variant=$2"; // default
 886                                         } else {
 887                                                 $variantArticlePath = $wgVariantArticlePath;
 888                                         }
 889                                         $url = str_replace( '$2', urlencode( $variant ), $variantArticlePath );
 890                                         $url = str_replace( '$1', $dbkey, $url  );
 891                                 } else {
 892                                         $url = str_replace( '$1', $dbkey, $wgArticlePath );
 893                                 }
 894                         } else {
 895                                 global $wgActionPaths;
 896                                 $url = false;
 897                                 $matches = array();
 898                                 if ( !empty( $wgActionPaths ) &&
 899                                         preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches ) )
 900                                 {
 901                                         $action = urldecode( $matches[2] );
 902                                         if ( isset( $wgActionPaths[$action] ) ) {
 903                                                 $query = $matches[1];
 904                                                 if ( isset( $matches[4] ) ) {
 905                                                         $query .= $matches[4];
 906                                                 }
 907                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
 908                                                 if ( $query != '' ) {
 909                                                         $url = wfAppendQuery( $url, $query );
 910                                                 }
 911                                         }
 912                                 }
 913                                 if ( $url === false ) {
 914                                         if ( $query == '-' ) {
 915                                                 $query = '';
 916                                         }
 917                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
 918                                 }
 919                         }
 920
 921                         // FIXME: this causes breakage in various places when we
 922                         // actually expected a local URL and end up with dupe prefixes.
 923                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
 924                                 $url = $wgServer . $url;
 925                         }
 926                 }
 927                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
 928                 return $url;
 929         }
 930
 931         /**
 932          * Get a URL that's the simplest URL that will be valid to link, locally,
 933          * to the current Title.  It includes the fragment, but does not include
 934          * the server unless action=render is used (or the link is external).  If
 935          * there's a fragment but the prefixed text is empty, we just return a link
 936          * to the fragment.
 937          *
 938          * The result obviously should not be URL-escaped, but does need to be
 939          * HTML-escaped if it's being output in HTML.
 940          *
 941          * @param $query Array of Strings An associative array of key => value pairs for the
 942          *   query string.  Keys and values will be escaped.
 943          * @param $variant String language variant of URL (for sr, zh..).  Ignored
 944          *   for external links.  Default is "false" (same variant as current page,
 945          *   for anonymous users).
 946          * @return String the URL
 947          */
 948         public function getLinkUrl( $query = array(), $variant = false ) {
 949                 wfProfileIn( __METHOD__ );
 950                 if ( $this->isExternal() ) {
 951                         $ret = $this->getFullURL( $query );
 952                 } elseif ( $this->getPrefixedText() === '' && $this->getFragment() !== '' ) {
 953                         $ret = $this->getFragmentForURL();
 954                 } else {
 955                         $ret = $this->getLocalURL( $query, $variant ) . $this->getFragmentForURL();
 956                 }
 957                 wfProfileOut( __METHOD__ );
 958                 return $ret;
 959         }
 960
 961         /**
 962          * Get an HTML-escaped version of the URL form, suitable for
 963          * using in a link, without a server name or fragment
 964          *
 965          * @param $query String an optional query string
 966          * @return String the URL
 967          */
 968         public function escapeLocalURL( $query = '' ) {
 969                 return htmlspecialchars( $this->getLocalURL( $query ) );
 970         }
 971
 972         /**
 973          * Get an HTML-escaped version of the URL form, suitable for
 974          * using in a link, including the server name and fragment
 975          *
 976          * @param $query String an optional query string
 977          * @return String the URL
 978          */
 979         public function escapeFullURL( $query = '' ) {
 980                 return htmlspecialchars( $this->getFullURL( $query ) );
 981         }
 982
 983         /**
 984          * Get the URL form for an internal link.
 985          * - Used in various Squid-related code, in case we have a different
 986          * internal hostname for the server from the exposed one.
 987          *
 988          * @param $query String an optional query string
 989          * @param $variant String language variant of url (for sr, zh..)
 990          * @return String the URL
 991          */
 992         public function getInternalURL( $query = '', $variant = false ) {
 993                 global $wgInternalServer, $wgServer;
 994                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
 995                 $url = $server . $this->getLocalURL( $query, $variant );
 996                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
 997                 return $url;
 998         }
 999
1000         /**
1001          * Get the edit URL for this Title
1002          *
1003          * @return String the URL, or a null string if this is an
1004          *  interwiki link
1005          */
1006         public function getEditURL() {
1007                 if ( $this->mInterwiki != '' ) {
1008                         return '';
1009                 }
1010                 $s = $this->getLocalURL( 'action=edit' );
1011
1012                 return $s;
1013         }
1014
1015         /**
1016          * Get the HTML-escaped displayable text form.
1017          * Used for the title field in <a> tags.
1018          *
1019          * @return String the text, including any prefixes
1020          */
1021         public function getEscapedText() {
1022                 return htmlspecialchars( $this->getPrefixedText() );
1023         }
1024
1025         /**
1026          * Is this Title interwiki?
1027          *
1028          * @return Bool
1029          */
1030         public function isExternal() {
1031                 return ( $this->mInterwiki != '' );
1032         }
1033
1034         /**
1035          * Is this page "semi-protected" - the *only* protection is autoconfirm?
1036          *
1037          * @param $action String Action to check (default: edit)
1038          * @return Bool
1039          */
1040         public function isSemiProtected( $action = 'edit' ) {
1041                 if ( $this->exists() ) {
1042                         $restrictions = $this->getRestrictions( $action );
1043                         if ( count( $restrictions ) > 0 ) {
1044                                 foreach ( $restrictions as $restriction ) {
1045                                         if ( strtolower( $restriction ) != 'autoconfirmed' ) {
1046                                                 return false;
1047                                         }
1048                                 }
1049                         } else {
1050                                 # Not protected
1051                                 return false;
1052                         }
1053                         return true;
1054                 } else {
1055                         # If it doesn't exist, it can't be protected
1056                         return false;
1057                 }
1058         }
1059
1060         /**
1061          * Does the title correspond to a protected article?
1062          *
1063          * @param $action String the action the page is protected from,
1064          * by default checks all actions.
1065          * @return Bool
1066          */
1067         public function isProtected( $action = '' ) {
1068                 global $wgRestrictionLevels;
1069
1070                 $restrictionTypes = $this->getRestrictionTypes();
1071
1072                 # Special pages have inherent protection
1073                 if( $this->getNamespace() == NS_SPECIAL ) {
1074                         return true;
1075                 }
1076
1077                 # Check regular protection levels
1078                 foreach ( $restrictionTypes as $type ) {
1079                         if ( $action == $type || $action == '' ) {
1080                                 $r = $this->getRestrictions( $type );
1081                                 foreach ( $wgRestrictionLevels as $level ) {
1082                                         if ( in_array( $level, $r ) && $level != '' ) {
1083                                                 return true;
1084                                         }
1085                                 }
1086                         }
1087                 }
1088
1089                 return false;
1090         }
1091
1092         /**
1093          * Is this a conversion table for the LanguageConverter?
1094          *
1095          * @return Bool
1096          */
1097         public function isConversionTable() {
1098                 if(
1099                         $this->getNamespace() == NS_MEDIAWIKI &&
1100                         strpos( $this->getText(), 'Conversiontable' ) !== false
1101                 )
1102                 {
1103                         return true;
1104                 }
1105
1106                 return false;
1107         }
1108
1109         /**
1110          * Is $wgUser watching this page?
1111          *
1112          * @return Bool
1113          */
1114         public function userIsWatching() {
1115                 global $wgUser;
1116
1117                 if ( is_null( $this->mWatched ) ) {
1118                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1119                                 $this->mWatched = false;
1120                         } else {
1121                                 $this->mWatched = $wgUser->isWatched( $this );
1122                         }
1123                 }
1124                 return $this->mWatched;
1125         }
1126
1127         /**
1128          * Can $wgUser perform $action on this page?
1129          * This skips potentially expensive cascading permission checks
1130          * as well as avoids expensive error formatting
1131          *
1132          * Suitable for use for nonessential UI controls in common cases, but
1133          * _not_ for functional access control.
1134          *
1135          * May provide false positives, but should never provide a false negative.
1136          *
1137          * @param $action String action that permission needs to be checked for
1138          * @return Bool
1139          */
1140         public function quickUserCan( $action ) {
1141                 return $this->userCan( $action, false );
1142         }
1143
1144         /**
1145          * Determines if $user is unable to edit this page because it has been protected
1146          * by $wgNamespaceProtection.
1147          *
1148          * @param $user User object, $wgUser will be used if not passed
1149          * @return Bool
1150          */
1151         public function isNamespaceProtected( User $user = null ) {
1152                 global $wgNamespaceProtection;
1153
1154                 if ( $user === null ) {
1155                         global $wgUser;
1156                         $user = $wgUser;
1157                 }
1158
1159                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
1160                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
1161                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
1162                                         return true;
1163                                 }
1164                         }
1165                 }
1166                 return false;
1167         }
1168
1169         /**
1170          * Can $wgUser perform $action on this page?
1171          *
1172          * @param $action String action that permission needs to be checked for
1173          * @param $doExpensiveQueries Bool Set this to false to avoid doing unnecessary queries.
1174          * @return Bool
1175          */
1176         public function userCan( $action, $doExpensiveQueries = true ) {
1177                 global $wgUser;
1178                 return ( $this->getUserPermissionsErrorsInternal( $action, $wgUser, $doExpensiveQueries, true ) === array() );
1179         }
1180
1181         /**
1182          * Can $user perform $action on this page?
1183          *
1184          * FIXME: This *does not* check throttles (User::pingLimiter()).
1185          *
1186          * @param $action String action that permission needs to be checked for
1187          * @param $user User to check
1188          * @param $doExpensiveQueries Bool Set this to false to avoid doing unnecessary queries.
1189          * @param $ignoreErrors Array of Strings Set this to a list of message keys whose corresponding errors may be ignored.
1190          * @return Array of arguments to wfMsg to explain permissions problems.
1191          */
1192         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
1193                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1194
1195                 // Remove the errors being ignored.
1196                 foreach ( $errors as $index => $error ) {
1197                         $error_key = is_array( $error ) ? $error[0] : $error;
1198
1199                         if ( in_array( $error_key, $ignoreErrors ) ) {
1200                                 unset( $errors[$index] );
1201                         }
1202                 }
1203
1204                 return $errors;
1205         }
1206
1207         /**
1208          * Permissions checks that fail most often, and which are easiest to test.
1209          *
1210          * @param $action String the action to check
1211          * @param $user User user to check
1212          * @param $errors Array list of current errors
1213          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1214          * @param $short Boolean short circuit on first error
1215          *
1216          * @return Array list of errors
1217          */
1218         private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1219                 if ( $action == 'create' ) {
1220                         if ( ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1221                                  ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) ) ) {
1222                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1223                         }
1224                 } elseif ( $action == 'move' ) {
1225                         if ( !$user->isAllowed( 'move-rootuserpages' )
1226                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1227                                 // Show user page-specific message only if the user can move other pages
1228                                 $errors[] = array( 'cant-move-user-page' );
1229                         }
1230
1231                         // Check if user is allowed to move files if it's a file
1232                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1233                                 $errors[] = array( 'movenotallowedfile' );
1234                         }
1235
1236                         if ( !$user->isAllowed( 'move' ) ) {
1237                                 // User can't move anything
1238                                 global $wgGroupPermissions;
1239                                 $userCanMove = false;
1240                                 if ( isset( $wgGroupPermissions['user']['move'] ) ) {
1241                                         $userCanMove = $wgGroupPermissions['user']['move'];
1242                                 }
1243                                 $autoconfirmedCanMove = false;
1244                                 if ( isset( $wgGroupPermissions['autoconfirmed']['move'] ) ) {
1245                                         $autoconfirmedCanMove = $wgGroupPermissions['autoconfirmed']['move'];
1246                                 }
1247                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1248                                         // custom message if logged-in users without any special rights can move
1249                                         $errors[] = array( 'movenologintext' );
1250                                 } else {
1251                                         $errors[] = array( 'movenotallowed' );
1252                                 }
1253                         }
1254                 } elseif ( $action == 'move-target' ) {
1255                         if ( !$user->isAllowed( 'move' ) ) {
1256                                 // User can't move anything
1257                                 $errors[] = array( 'movenotallowed' );
1258                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1259                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1260                                 // Show user page-specific message only if the user can move other pages
1261                                 $errors[] = array( 'cant-move-to-user-page' );
1262                         }
1263                 } elseif ( !$user->isAllowed( $action ) ) {
1264                         // We avoid expensive display logic for quickUserCan's and such
1265                         $groups = false;
1266                         if ( !$short ) {
1267                                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
1268                                         User::getGroupsWithPermission( $action ) );
1269                         }
1270
1271                         if ( $groups ) {
1272                                 global $wgLang;
1273                                 $return = array(
1274                                         'badaccess-groups',
1275                                         $wgLang->commaList( $groups ),
1276                                         count( $groups )
1277                                 );
1278                         } else {
1279                                 $return = array( 'badaccess-group0' );
1280                         }
1281                         $errors[] = $return;
1282                 }
1283
1284                 return $errors;
1285         }
1286
1287         /**
1288          * Add the resulting error code to the errors array
1289          *
1290          * @param $errors Array list of current errors
1291          * @param $result Mixed result of errors
1292          *
1293          * @return Array list of errors
1294          */
1295         private function resultToError( $errors, $result ) {
1296                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1297                         // A single array representing an error
1298                         $errors[] = $result;
1299                 } else if ( is_array( $result ) && is_array( $result[0] ) ) {
1300                         // A nested array representing multiple errors
1301                         $errors = array_merge( $errors, $result );
1302                 } else if ( $result !== '' && is_string( $result ) ) {
1303                         // A string representing a message-id
1304                         $errors[] = array( $result );
1305                 } else if ( $result === false ) {
1306                         // a generic "We don't want them to do that"
1307                         $errors[] = array( 'badaccess-group0' );
1308                 }
1309                 return $errors;
1310         }
1311
1312         /**
1313          * Check various permission hooks
1314          *
1315          * @param $action String the action to check
1316          * @param $user User user to check
1317          * @param $errors Array list of current errors
1318          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1319          * @param $short Boolean short circuit on first error
1320          *
1321          * @return Array list of errors
1322          */
1323         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
1324                 // Use getUserPermissionsErrors instead
1325                 $result = '';
1326                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
1327                         return $result ? array() : array( array( 'badaccess-group0' ) );
1328                 }
1329                 // Check getUserPermissionsErrors hook
1330                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
1331                         $errors = $this->resultToError( $errors, $result );
1332                 }
1333                 // Check getUserPermissionsErrorsExpensive hook
1334                 if ( $doExpensiveQueries && !( $short && count( $errors ) > 0 ) &&
1335                          !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) ) ) {
1336                         $errors = $this->resultToError( $errors, $result );
1337                 }
1338
1339                 return $errors;
1340         }
1341
1342         /**
1343          * Check permissions on special pages & namespaces
1344          *
1345          * @param $action String the action to check
1346          * @param $user User user to check
1347          * @param $errors Array list of current errors
1348          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1349          * @param $short Boolean short circuit on first error
1350          *
1351          * @return Array list of errors
1352          */
1353         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1354                 # Only 'createaccount' and 'execute' can be performed on
1355                 # special pages, which don't actually exist in the DB.
1356                 $specialOKActions = array( 'createaccount', 'execute' );
1357                 if ( NS_SPECIAL == $this->mNamespace && !in_array( $action, $specialOKActions ) ) {
1358                         $errors[] = array( 'ns-specialprotected' );
1359                 }
1360
1361                 # Check $wgNamespaceProtection for restricted namespaces
1362                 if ( $this->isNamespaceProtected( $user ) ) {
1363                         $ns = $this->mNamespace == NS_MAIN ?
1364                                 wfMsg( 'nstab-main' ) : $this->getNsText();
1365                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
1366                                 array( 'protectedinterface' ) : array( 'namespaceprotected',  $ns );
1367                 }
1368
1369                 return $errors;
1370         }
1371
1372         /**
1373          * Check CSS/JS sub-page permissions
1374          *
1375          * @param $action String the action to check
1376          * @param $user User user to check
1377          * @param $errors Array list of current errors
1378          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1379          * @param $short Boolean short circuit on first error
1380          *
1381          * @return Array list of errors
1382          */
1383         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1384                 # Protect css/js subpages of user pages
1385                 # XXX: this might be better using restrictions
1386                 # XXX: Find a way to work around the php bug that prevents using $this->userCanEditCssSubpage()
1387                 #      and $this->userCanEditJsSubpage() from working
1388                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
1389                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' )
1390                                 && !preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
1391                         if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
1392                                 $errors[] = array( 'customcssjsprotected' );
1393                         } else if ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
1394                                 $errors[] = array( 'customcssjsprotected' );
1395                         }
1396                 }
1397
1398                 return $errors;
1399         }
1400
1401         /**
1402          * Check against page_restrictions table requirements on this
1403          * page. The user must possess all required rights for this
1404          * action.
1405          *
1406          * @param $action String the action to check
1407          * @param $user User user to check
1408          * @param $errors Array list of current errors
1409          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1410          * @param $short Boolean short circuit on first error
1411          *
1412          * @return Array list of errors
1413          */
1414         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1415                 foreach ( $this->getRestrictions( $action ) as $right ) {
1416                         // Backwards compatibility, rewrite sysop -> protect
1417                         if ( $right == 'sysop' ) {
1418                                 $right = 'protect';
1419                         }
1420                         if ( $right != '' && !$user->isAllowed( $right ) ) {
1421                                 // Users with 'editprotected' permission can edit protected pages
1422                                 if ( $action == 'edit' && $user->isAllowed( 'editprotected' ) ) {
1423                                         // Users with 'editprotected' permission cannot edit protected pages
1424                                         // with cascading option turned on.
1425                                         if ( $this->mCascadeRestriction ) {
1426                                                 $errors[] = array( 'protectedpagetext', $right );
1427                                         }
1428                                 } else {
1429                                         $errors[] = array( 'protectedpagetext', $right );
1430                                 }
1431                         }
1432                 }
1433
1434                 return $errors;
1435         }
1436
1437         /**
1438          * Check restrictions on cascading pages.
1439          *
1440          * @param $action String the action to check
1441          * @param $user User to check
1442          * @param $errors Array list of current errors
1443          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1444          * @param $short Boolean short circuit on first error
1445          *
1446          * @return Array list of errors
1447          */
1448         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1449                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
1450                         # We /could/ use the protection level on the source page, but it's
1451                         # fairly ugly as we have to establish a precedence hierarchy for pages
1452                         # included by multiple cascade-protected pages. So just restrict
1453                         # it to people with 'protect' permission, as they could remove the
1454                         # protection anyway.
1455                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
1456                         # Cascading protection depends on more than this page...
1457                         # Several cascading protected pages may include this page...
1458                         # Check each cascading level
1459                         # This is only for protection restrictions, not for all actions
1460                         if ( isset( $restrictions[$action] ) ) {
1461                                 foreach ( $restrictions[$action] as $right ) {
1462                                         $right = ( $right == 'sysop' ) ? 'protect' : $right;
1463                                         if ( $right != '' && !$user->isAllowed( $right ) ) {
1464                                                 $pages = '';
1465                                                 foreach ( $cascadingSources as $page )
1466                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
1467                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
1468                                         }
1469                                 }
1470                         }
1471                 }
1472
1473                 return $errors;
1474         }
1475
1476         /**
1477          * Check action permissions not already checked in checkQuickPermissions
1478          *
1479          * @param $action String the action to check
1480          * @param $user User to check
1481          * @param $errors Array list of current errors
1482          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1483          * @param $short Boolean short circuit on first error
1484          *
1485          * @return Array list of errors
1486          */
1487         private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1488                 if ( $action == 'protect' ) {
1489                         if ( $this->getUserPermissionsErrors( 'edit', $user ) != array() ) {
1490                                 // If they can't edit, they shouldn't protect.
1491                                 $errors[] = array( 'protect-cantedit' );
1492                         }
1493                 } elseif ( $action == 'create' ) {
1494                         $title_protection = $this->getTitleProtection();
1495                         if( $title_protection ) {
1496                                 if( $title_protection['pt_create_perm'] == 'sysop' ) {
1497                                         $title_protection['pt_create_perm'] = 'protect'; // B/C
1498                                 }
1499                                 if( $title_protection['pt_create_perm'] == '' || !$user->isAllowed( $title_protection['pt_create_perm'] ) ) {
1500                                         $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
1501                                 }
1502                         }
1503                 } elseif ( $action == 'move' ) {
1504                         // Check for immobile pages
1505                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
1506                                 // Specific message for this case
1507                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
1508                         } elseif ( !$this->isMovable() ) {
1509                                 // Less specific message for rarer cases
1510                                 $errors[] = array( 'immobile-page' );
1511                         }
1512                 } elseif ( $action == 'move-target' ) {
1513                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
1514                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
1515                         } elseif ( !$this->isMovable() ) {
1516                                 $errors[] = array( 'immobile-target-page' );
1517                         }
1518                 }
1519                 return $errors;
1520         }
1521
1522         /**
1523          * Check that the user isn't blocked from editting.
1524          *
1525          * @param $action String the action to check
1526          * @param $user User to check
1527          * @param $errors Array list of current errors
1528          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1529          * @param $short Boolean short circuit on first error
1530          *
1531          * @return Array list of errors
1532          */
1533         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
1534                 if( $short && count( $errors ) > 0 ) {
1535                         return $errors;
1536                 }
1537
1538                 global $wgContLang, $wgLang, $wgEmailConfirmToEdit;
1539
1540                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() && $action != 'createaccount' ) {
1541                         $errors[] = array( 'confirmedittext' );
1542                 }
1543
1544                 if ( in_array( $action, array( 'read', 'createaccount', 'unblock' ) ) ){
1545                         // Edit blocks should not affect reading.
1546                         // Account creation blocks handled at userlogin.
1547                         // Unblocking handled in SpecialUnblock
1548                 } elseif( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ){
1549                         // Don't block the user from editing their own talk page unless they've been
1550                         // explicitly blocked from that too.
1551                 } elseif( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
1552                         $block = $user->mBlock;
1553
1554                         // This is from OutputPage::blockedPage
1555                         // Copied at r23888 by werdna
1556
1557                         $id = $user->blockedBy();
1558                         $reason = $user->blockedFor();
1559                         if ( $reason == '' ) {
1560                                 $reason = wfMsg( 'blockednoreason' );
1561                         }
1562                         $ip = wfGetIP();
1563
1564                         if ( is_numeric( $id ) ) {
1565                                 $name = User::whoIs( $id );
1566                         } else {
1567                                 $name = $id;
1568                         }
1569
1570                         $link = '[[' . $wgContLang->getNsText( NS_USER ) . ":{$name}|{$name}]]";
1571                         $blockid = $block->getId();
1572                         $blockExpiry = $user->mBlock->mExpiry;
1573                         $blockTimestamp = $wgLang->timeanddate( wfTimestamp( TS_MW, $user->mBlock->mTimestamp ), true );
1574                         if ( $blockExpiry == 'infinity' ) {
1575                                 $blockExpiry = wfMessage( 'infiniteblock' );
1576                         } else {
1577                                 $blockExpiry = $wgLang->timeanddate( wfTimestamp( TS_MW, $blockExpiry ), true );
1578                         }
1579
1580                         $intended = $user->mBlock->getTarget();
1581
1582                         $errors[] = array( ( $block->mAuto ? 'autoblockedtext' : 'blockedtext' ), $link, $reason, $ip, $name,
1583                                 $blockid, $blockExpiry, $intended, $blockTimestamp );
1584                 }
1585
1586                 return $errors;
1587         }
1588
1589         /**
1590          * Can $user perform $action on this page? This is an internal function,
1591          * which checks ONLY that previously checked by userCan (i.e. it leaves out
1592          * checks on wfReadOnly() and blocks)
1593          *
1594          * @param $action String action that permission needs to be checked for
1595          * @param $user User to check
1596          * @param $doExpensiveQueries Bool Set this to false to avoid doing unnecessary queries.
1597          * @param $short Bool Set this to true to stop after the first permission error.
1598          * @return Array of arrays of the arguments to wfMsg to explain permissions problems.
1599          */
1600         protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
1601                 wfProfileIn( __METHOD__ );
1602
1603                 $errors = array();
1604                 $checks = array(
1605                         'checkQuickPermissions',
1606                         'checkPermissionHooks',
1607                         'checkSpecialsAndNSPermissions',
1608                         'checkCSSandJSPermissions',
1609                         'checkPageRestrictions',
1610                         'checkCascadingSourcesRestrictions',
1611                         'checkActionPermissions',
1612                         'checkUserBlock'
1613                 );
1614
1615                 while( count( $checks ) > 0 &&
1616                            !( $short && count( $errors ) > 0 ) ) {
1617                         $method = array_shift( $checks );
1618                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
1619                 }
1620
1621                 wfProfileOut( __METHOD__ );
1622                 return $errors;
1623         }
1624
1625         /**
1626          * Is this title subject to title protection?
1627          * Title protection is the one applied against creation of such title.
1628          *
1629          * @return Mixed An associative array representing any existent title
1630          *   protection, or false if there's none.
1631          */
1632         private function getTitleProtection() {
1633                 // Can't protect pages in special namespaces
1634                 if ( $this->getNamespace() < 0 ) {
1635                         return false;
1636                 }
1637
1638                 // Can't protect pages that exist.
1639                 if ( $this->exists() ) {
1640                         return false;
1641                 }
1642
1643                 if ( !isset( $this->mTitleProtection ) ) {
1644                         $dbr = wfGetDB( DB_SLAVE );
1645                         $res = $dbr->select( 'protected_titles', '*',
1646                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
1647                                 __METHOD__ );
1648
1649                         // fetchRow returns false if there are no rows.
1650                         $this->mTitleProtection = $dbr->fetchRow( $res );
1651                 }
1652                 return $this->mTitleProtection;
1653         }
1654
1655         /**
1656          * Update the title protection status
1657          *
1658          * @param $create_perm String Permission required for creation
1659          * @param $reason String Reason for protection
1660          * @param $expiry String Expiry timestamp
1661          * @return boolean true
1662          */
1663         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
1664                 global $wgUser, $wgContLang;
1665
1666                 if ( $create_perm == implode( ',', $this->getRestrictions( 'create' ) )
1667                         && $expiry == $this->mRestrictionsExpiry['create'] ) {
1668                         // No change
1669                         return true;
1670                 }
1671
1672                 list ( $namespace, $title ) = array( $this->getNamespace(), $this->getDBkey() );
1673
1674                 $dbw = wfGetDB( DB_MASTER );
1675
1676                 $encodedExpiry = $dbw->encodeExpiry( $expiry );
1677
1678                 $expiry_description = '';
1679                 if ( $encodedExpiry != $dbw->getInfinity() ) {
1680                         $expiry_description = ' (' . wfMsgForContent( 'protect-expiring', $wgContLang->timeanddate( $expiry ),
1681                                 $wgContLang->date( $expiry ) , $wgContLang->time( $expiry ) ) . ')';
1682                 } else {
1683                         $expiry_description .= ' (' . wfMsgForContent( 'protect-expiry-indefinite' ) . ')';
1684                 }
1685
1686                 # Update protection table
1687                 if ( $create_perm != '' ) {
1688                         $this->mTitleProtection = array(
1689                                         'pt_namespace' => $namespace,
1690                                         'pt_title' => $title,
1691                                         'pt_create_perm' => $create_perm,
1692                                         'pt_timestamp' => $dbw->encodeExpiry( wfTimestampNow() ),
1693                                         'pt_expiry' => $encodedExpiry,
1694                                         'pt_user' => $wgUser->getId(),
1695                                         'pt_reason' => $reason,
1696                                 );
1697                         $dbw->replace( 'protected_titles', array( array( 'pt_namespace', 'pt_title' ) ),
1698                                 $this->mTitleProtection, __METHOD__     );
1699                 } else {
1700                         $dbw->delete( 'protected_titles', array( 'pt_namespace' => $namespace,
1701                                 'pt_title' => $title ), __METHOD__ );
1702                         $this->mTitleProtection = false;
1703                 }
1704
1705                 # Update the protection log
1706                 if ( $dbw->affectedRows() ) {
1707                         $log = new LogPage( 'protect' );
1708
1709                         if ( $create_perm ) {
1710                                 $params = array( "[create=$create_perm] $expiry_description", '' );
1711                                 $log->addEntry( ( isset( $this->mRestrictions['create'] ) && $this->mRestrictions['create'] ) ? 'modify' : 'protect', $this, trim( $reason ), $params );
1712                         } else {
1713                                 $log->addEntry( 'unprotect', $this, $reason );
1714                         }
1715                 }
1716
1717                 return true;
1718         }
1719
1720         /**
1721          * Remove any title protection due to page existing
1722          */
1723         public function deleteTitleProtection() {
1724                 $dbw = wfGetDB( DB_MASTER );
1725
1726                 $dbw->delete(
1727                         'protected_titles',
1728                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
1729                         __METHOD__
1730                 );
1731                 $this->mTitleProtection = false;
1732         }
1733
1734         /**
1735          * Would anybody with sufficient privileges be able to move this page?
1736          * Some pages just aren't movable.
1737          *
1738          * @return Bool TRUE or FALSE
1739          */
1740         public function isMovable() {
1741                 return MWNamespace::isMovable( $this->getNamespace() ) && $this->getInterwiki() == '';
1742         }
1743
1744         /**
1745          * Can $wgUser read this page?
1746          *
1747          * @return Bool
1748          * @todo fold these checks into userCan()
1749          */
1750         public function userCanRead() {
1751                 global $wgUser, $wgGroupPermissions;
1752
1753                 static $useShortcut = null;
1754
1755                 # Initialize the $useShortcut boolean, to determine if we can skip quite a bit of code below
1756                 if ( is_null( $useShortcut ) ) {
1757                         global $wgRevokePermissions;
1758                         $useShortcut = true;
1759                         if ( empty( $wgGroupPermissions['*']['read'] ) ) {
1760                                 # Not a public wiki, so no shortcut
1761                                 $useShortcut = false;
1762                         } elseif ( !empty( $wgRevokePermissions ) ) {
1763                                 /*
1764                                  * Iterate through each group with permissions being revoked (key not included since we don't care
1765                                  * what the group name is), then check if the read permission is being revoked. If it is, then
1766                                  * we don't use the shortcut below since the user might not be able to read, even though anon
1767                                  * reading is allowed.
1768                                  */
1769                                 foreach ( $wgRevokePermissions as $perms ) {
1770                                         if ( !empty( $perms['read'] ) ) {
1771                                                 # We might be removing the read right from the user, so no shortcut
1772                                                 $useShortcut = false;
1773                                                 break;
1774                                         }
1775                                 }
1776                         }
1777                 }
1778
1779                 $result = null;
1780                 wfRunHooks( 'userCan', array( &$this, &$wgUser, 'read', &$result ) );
1781                 if ( $result !== null ) {
1782                         return $result;
1783                 }
1784
1785                 # Shortcut for public wikis, allows skipping quite a bit of code
1786                 if ( $useShortcut ) {
1787                         return true;
1788                 }
1789
1790                 if ( $wgUser->isAllowed( 'read' ) ) {
1791                         return true;
1792                 } else {
1793                         global $wgWhitelistRead;
1794
1795                         # Always grant access to the login page.
1796                         # Even anons need to be able to log in.
1797                         if ( $this->isSpecial( 'Userlogin' ) || $this->isSpecial( 'Resetpass' ) ) {
1798                                 return true;
1799                         }
1800
1801                         # Bail out if there isn't whitelist
1802                         if ( !is_array( $wgWhitelistRead ) ) {
1803                                 return false;
1804                         }
1805
1806                         # Check for explicit whitelisting
1807                         $name = $this->getPrefixedText();
1808                         $dbName = $this->getPrefixedDBKey();
1809                         // Check with and without underscores
1810                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) )
1811                                 return true;
1812
1813                         # Old settings might have the title prefixed with
1814                         # a colon for main-namespace pages
1815                         if ( $this->getNamespace() == NS_MAIN ) {
1816                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
1817                                         return true;
1818                                 }
1819                         }
1820
1821                         # If it's a special page, ditch the subpage bit and check again
1822                         if ( $this->getNamespace() == NS_SPECIAL ) {
1823                                 $name = $this->getDBkey();
1824                                 list( $name, /* $subpage */ ) = SpecialPage::resolveAliasWithSubpage( $name );
1825                                 if ( $name === false ) {
1826                                         # Invalid special page, but we show standard login required message
1827                                         return false;
1828                                 }
1829
1830                                 $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
1831                                 if ( in_array( $pure, $wgWhitelistRead, true ) ) {
1832                                         return true;
1833                                 }
1834                         }
1835
1836                 }
1837                 return false;
1838         }
1839
1840         /**
1841          * Is this the mainpage?
1842          * @note Title::newFromText seams to be sufficiently optimized by the title
1843          * cache that we don't need to over-optimize by doing direct comparisons and
1844          * acidentally creating new bugs where $title->equals( Title::newFromText() )
1845          * ends up reporting something differently than $title->isMainPage();
1846          *
1847          * @return Bool
1848          */
1849         public function isMainPage() {
1850                 return $this->equals( Title::newMainPage() );
1851         }
1852
1853         /**
1854          * Is this a talk page of some sort?
1855          *
1856          * @return Bool
1857          */
1858         public function isTalkPage() {
1859                 return MWNamespace::isTalk( $this->getNamespace() );
1860         }
1861
1862         /**
1863          * Is this a subpage?
1864          *
1865          * @return Bool
1866          */
1867         public function isSubpage() {
1868                 return MWNamespace::hasSubpages( $this->mNamespace )
1869                         ? strpos( $this->getText(), '/' ) !== false
1870                         : false;
1871         }
1872
1873         /**
1874          * Does this have subpages?  (Warning, usually requires an extra DB query.)
1875          *
1876          * @return Bool
1877          */
1878         public function hasSubpages() {
1879                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1880                         # Duh
1881                         return false;
1882                 }
1883
1884                 # We dynamically add a member variable for the purpose of this method
1885                 # alone to cache the result.  There's no point in having it hanging
1886                 # around uninitialized in every Title object; therefore we only add it
1887                 # if needed and don't declare it statically.
1888                 if ( isset( $this->mHasSubpages ) ) {
1889                         return $this->mHasSubpages;
1890                 }
1891
1892                 $subpages = $this->getSubpages( 1 );
1893                 if ( $subpages instanceof TitleArray ) {
1894                         return $this->mHasSubpages = (bool)$subpages->count();
1895                 }
1896                 return $this->mHasSubpages = false;
1897         }
1898
1899         /**
1900          * Get all subpages of this page.
1901          *
1902          * @param $limit Int maximum number of subpages to fetch; -1 for no limit
1903          * @return mixed TitleArray, or empty array if this page's namespace
1904          *  doesn't allow subpages
1905          */
1906         public function getSubpages( $limit = -1 ) {
1907                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
1908                         return array();
1909                 }
1910
1911                 $dbr = wfGetDB( DB_SLAVE );
1912                 $conds['page_namespace'] = $this->getNamespace();
1913                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
1914                 $options = array();
1915                 if ( $limit > -1 ) {
1916                         $options['LIMIT'] = $limit;
1917                 }
1918                 return $this->mSubpages = TitleArray::newFromResult(
1919                         $dbr->select( 'page',
1920                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
1921                                 $conds,
1922                                 __METHOD__,
1923                                 $options
1924                         )
1925                 );
1926         }
1927
1928         /**
1929          * Could this page contain custom CSS or JavaScript, based
1930          * on the title?
1931          *
1932          * @return Bool
1933          */
1934         public function isCssOrJsPage() {
1935                 return $this->mNamespace == NS_MEDIAWIKI
1936                         && preg_match( '!\.(?:css|js)$!u', $this->mTextform ) > 0;
1937         }
1938
1939         /**
1940          * Is this a .css or .js subpage of a user page?
1941          * @return Bool
1942          */
1943         public function isCssJsSubpage() {
1944                 return ( NS_USER == $this->mNamespace and preg_match( "/\\/.*\\.(?:css|js)$/", $this->mTextform ) );
1945         }
1946
1947         /**
1948          * Is this a *valid* .css or .js subpage of a user page?
1949          *
1950          * @return Bool
1951          * @deprecated since 1.17
1952          */
1953         public function isValidCssJsSubpage() {
1954                 return $this->isCssJsSubpage();
1955         }
1956
1957         /**
1958          * Trim down a .css or .js subpage title to get the corresponding skin name
1959          *
1960          * @return string containing skin name from .css or .js subpage title
1961          */
1962         public function getSkinFromCssJsSubpage() {
1963                 $subpage = explode( '/', $this->mTextform );
1964                 $subpage = $subpage[ count( $subpage ) - 1 ];
1965                 return( str_replace( array( '.css', '.js' ), array( '', '' ), $subpage ) );
1966         }
1967
1968         /**
1969          * Is this a .css subpage of a user page?
1970          *
1971          * @return Bool
1972          */
1973         public function isCssSubpage() {
1974                 return ( NS_USER == $this->mNamespace && preg_match( "/\\/.*\\.css$/", $this->mTextform ) );
1975         }
1976
1977         /**
1978          * Is this a .js subpage of a user page?
1979          *
1980          * @return Bool
1981          */
1982         public function isJsSubpage() {
1983                 return ( NS_USER == $this->mNamespace && preg_match( "/\\/.*\\.js$/", $this->mTextform ) );
1984         }
1985
1986         /**
1987          * Protect css subpages of user pages: can $wgUser edit
1988          * this page?
1989          *
1990          * @return Bool
1991          * @todo XXX: this might be better using restrictions
1992          */
1993         public function userCanEditCssSubpage() {
1994                 global $wgUser;
1995                 return ( ( $wgUser->isAllowedAll( 'editusercssjs', 'editusercss' ) )
1996                         || preg_match( '/^' . preg_quote( $wgUser->getName(), '/' ) . '\//', $this->mTextform ) );
1997         }
1998
1999         /**
2000          * Protect js subpages of user pages: can $wgUser edit
2001          * this page?
2002          *
2003          * @return Bool
2004          * @todo XXX: this might be better using restrictions
2005          */
2006         public function userCanEditJsSubpage() {
2007                 global $wgUser;
2008                 return ( ( $wgUser->isAllowedAll( 'editusercssjs', 'edituserjs' ) )
2009                            || preg_match( '/^' . preg_quote( $wgUser->getName(), '/' ) . '\//', $this->mTextform ) );
2010         }
2011
2012         /**
2013          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2014          *
2015          * @return Bool If the page is subject to cascading restrictions.
2016          */
2017         public function isCascadeProtected() {
2018                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2019                 return ( $sources > 0 );
2020         }
2021
2022         /**
2023          * Cascading protection: Get the source of any cascading restrictions on this page.
2024          *
2025          * @param $getPages Bool Whether or not to retrieve the actual pages
2026          *        that the restrictions have come from.
2027          * @return Mixed Array of Title objects of the pages from which cascading restrictions
2028          *     have come, false for none, or true if such restrictions exist, but $getPages
2029          *     was not set.  The restriction array is an array of each type, each of which
2030          *     contains a array of unique groups.
2031          */
2032         public function getCascadeProtectionSources( $getPages = true ) {
2033                 global $wgContLang;
2034                 $pagerestrictions = array();
2035
2036                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2037                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2038                 } else if ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2039                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2040                 }
2041
2042                 wfProfileIn( __METHOD__ );
2043
2044                 $dbr = wfGetDB( DB_SLAVE );
2045
2046                 if ( $this->getNamespace() == NS_FILE ) {
2047                         $tables = array( 'imagelinks', 'page_restrictions' );
2048                         $where_clauses = array(
2049                                 'il_to' => $this->getDBkey(),
2050                                 'il_from=pr_page',
2051                                 'pr_cascade' => 1
2052                         );
2053                 } else {
2054                         $tables = array( 'templatelinks', 'page_restrictions' );
2055                         $where_clauses = array(
2056                                 'tl_namespace' => $this->getNamespace(),
2057                                 'tl_title' => $this->getDBkey(),
2058                                 'tl_from=pr_page',
2059                                 'pr_cascade' => 1
2060                         );
2061                 }
2062
2063                 if ( $getPages ) {
2064                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2065                                                    'pr_expiry', 'pr_type', 'pr_level' );
2066                         $where_clauses[] = 'page_id=pr_page';
2067                         $tables[] = 'page';
2068                 } else {
2069                         $cols = array( 'pr_expiry' );
2070                 }
2071
2072                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2073
2074                 $sources = $getPages ? array() : false;
2075                 $now = wfTimestampNow();
2076                 $purgeExpired = false;
2077
2078                 foreach ( $res as $row ) {
2079                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2080                         if ( $expiry > $now ) {
2081                                 if ( $getPages ) {
2082                                         $page_id = $row->pr_page;
2083                                         $page_ns = $row->page_namespace;
2084                                         $page_title = $row->page_title;
2085                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2086                                         # Add groups needed for each restriction type if its not already there
2087                                         # Make sure this restriction type still exists
2088
2089                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2090                                                 $pagerestrictions[$row->pr_type] = array();
2091                                         }
2092
2093                                         if ( isset( $pagerestrictions[$row->pr_type] ) &&
2094                                                  !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] ) ) {
2095                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2096                                         }
2097                                 } else {
2098                                         $sources = true;
2099                                 }
2100                         } else {
2101                                 // Trigger lazy purge of expired restrictions from the db
2102                                 $purgeExpired = true;
2103                         }
2104                 }
2105                 if ( $purgeExpired ) {
2106                         Title::purgeExpiredRestrictions();
2107                 }
2108
2109                 if ( $getPages ) {
2110                         $this->mCascadeSources = $sources;
2111                         $this->mCascadingRestrictions = $pagerestrictions;
2112                 } else {
2113                         $this->mHasCascadingRestrictions = $sources;
2114                 }
2115
2116                 wfProfileOut( __METHOD__ );
2117                 return array( $sources, $pagerestrictions );
2118         }
2119
2120         /**
2121          * Returns cascading restrictions for the current article
2122          *
2123          * @return Boolean
2124          */
2125         function areRestrictionsCascading() {
2126                 if ( !$this->mRestrictionsLoaded ) {
2127                         $this->loadRestrictions();
2128                 }
2129
2130                 return $this->mCascadeRestriction;
2131         }
2132
2133         /**
2134          * Loads a string into mRestrictions array
2135          *
2136          * @param $res Resource restrictions as an SQL result.
2137          * @param $oldFashionedRestrictions String comma-separated list of page
2138          *        restrictions from page table (pre 1.10)
2139          */
2140         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2141                 $rows = array();
2142
2143                 foreach ( $res as $row ) {
2144                         $rows[] = $row;
2145                 }
2146
2147                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2148         }
2149
2150         /**
2151          * Compiles list of active page restrictions from both page table (pre 1.10)
2152          * and page_restrictions table for this existing page.
2153          * Public for usage by LiquidThreads.
2154          *
2155          * @param $rows array of db result objects
2156          * @param $oldFashionedRestrictions string comma-separated list of page
2157          *        restrictions from page table (pre 1.10)
2158          */
2159         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2160                 global $wgContLang;
2161                 $dbr = wfGetDB( DB_SLAVE );
2162
2163                 $restrictionTypes = $this->getRestrictionTypes();
2164
2165                 foreach ( $restrictionTypes as $type ) {
2166                         $this->mRestrictions[$type] = array();
2167                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2168                 }
2169
2170                 $this->mCascadeRestriction = false;
2171
2172                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2173
2174                 if ( $oldFashionedRestrictions === null ) {
2175                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2176                                 array( 'page_id' => $this->getArticleId() ), __METHOD__ );
2177                 }
2178
2179                 if ( $oldFashionedRestrictions != '' ) {
2180
2181                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2182                                 $temp = explode( '=', trim( $restrict ) );
2183                                 if ( count( $temp ) == 1 ) {
2184                                         // old old format should be treated as edit/move restriction
2185                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2186                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2187                                 } else {
2188                                         $this->mRestrictions[$temp[0]] = explode( ',', trim( $temp[1] ) );
2189                                 }
2190                         }
2191
2192                         $this->mOldRestrictions = true;
2193
2194                 }
2195
2196                 if ( count( $rows ) ) {
2197                         # Current system - load second to make them override.
2198                         $now = wfTimestampNow();
2199                         $purgeExpired = false;
2200
2201                         # Cycle through all the restrictions.
2202                         foreach ( $rows as $row ) {
2203
2204                                 // Don't take care of restrictions types that aren't allowed
2205                                 if ( !in_array( $row->pr_type, $restrictionTypes ) )
2206                                         continue;
2207
2208                                 // This code should be refactored, now that it's being used more generally,
2209                                 // But I don't really see any harm in leaving it in Block for now -werdna
2210                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2211
2212                                 // Only apply the restrictions if they haven't expired!
2213                                 if ( !$expiry || $expiry > $now ) {
2214                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2215                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2216
2217                                         $this->mCascadeRestriction |= $row->pr_cascade;
2218                                 } else {
2219                                         // Trigger a lazy purge of expired restrictions
2220                                         $purgeExpired = true;
2221                                 }
2222                         }
2223
2224                         if ( $purgeExpired ) {
2225                                 Title::purgeExpiredRestrictions();
2226                         }
2227                 }
2228
2229                 $this->mRestrictionsLoaded = true;
2230         }
2231
2232         /**
2233          * Load restrictions from the page_restrictions table
2234          *
2235          * @param $oldFashionedRestrictions String comma-separated list of page
2236          *        restrictions from page table (pre 1.10)
2237          */
2238         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2239                 global $wgContLang;
2240                 if ( !$this->mRestrictionsLoaded ) {
2241                         if ( $this->exists() ) {
2242                                 $dbr = wfGetDB( DB_SLAVE );
2243
2244                                 $res = $dbr->select(
2245                                         'page_restrictions',
2246                                         '*',
2247                                         array( 'pr_page' => $this->getArticleId() ),
2248                                         __METHOD__
2249                                 );
2250
2251                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2252                         } else {
2253                                 $title_protection = $this->getTitleProtection();
2254
2255                                 if ( $title_protection ) {
2256                                         $now = wfTimestampNow();
2257                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2258
2259                                         if ( !$expiry || $expiry > $now ) {
2260                                                 // Apply the restrictions
2261                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2262                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2263                                         } else { // Get rid of the old restrictions
2264                                                 Title::purgeExpiredRestrictions();
2265                                                 $this->mTitleProtection = false;
2266                                         }
2267                                 } else {
2268                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2269                                 }
2270                                 $this->mRestrictionsLoaded = true;
2271                         }
2272                 }
2273         }
2274
2275         /**
2276          * Purge expired restrictions from the page_restrictions table
2277          */
2278         static function purgeExpiredRestrictions() {
2279                 $dbw = wfGetDB( DB_MASTER );
2280                 $dbw->delete(
2281                         'page_restrictions',
2282                         array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2283                         __METHOD__
2284                 );
2285
2286                 $dbw->delete(
2287                         'protected_titles',
2288                         array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2289                         __METHOD__
2290                 );
2291         }
2292
2293         /**
2294          * Accessor/initialisation for mRestrictions
2295          *
2296          * @param $action String action that permission needs to be checked for
2297          * @return Array of Strings the array of groups allowed to edit this article
2298          */
2299         public function getRestrictions( $action ) {
2300                 if ( !$this->mRestrictionsLoaded ) {
2301                         $this->loadRestrictions();
2302                 }
2303                 return isset( $this->mRestrictions[$action] )
2304                                 ? $this->mRestrictions[$action]
2305                                 : array();
2306         }
2307
2308         /**
2309          * Get the expiry time for the restriction against a given action
2310          *
2311          * @return String|Bool 14-char timestamp, or 'infinity' if the page is protected forever
2312          *      or not protected at all, or false if the action is not recognised.
2313          */
2314         public function getRestrictionExpiry( $action ) {
2315                 if ( !$this->mRestrictionsLoaded ) {
2316                         $this->loadRestrictions();
2317                 }
2318                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2319         }
2320
2321         /**
2322          * Is there a version of this page in the deletion archive?
2323          *
2324          * @return Int the number of archived revisions
2325          */
2326         public function isDeleted() {
2327                 if ( $this->getNamespace() < 0 ) {
2328                         $n = 0;
2329                 } else {
2330                         $dbr = wfGetDB( DB_SLAVE );
2331                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
2332                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2333                                 __METHOD__
2334                         );
2335                         if ( $this->getNamespace() == NS_FILE ) {
2336                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
2337                                         array( 'fa_name' => $this->getDBkey() ),
2338                                         __METHOD__
2339                                 );
2340                         }
2341                 }
2342                 return (int)$n;
2343         }
2344
2345         /**
2346          * Is there a version of this page in the deletion archive?
2347          *
2348          * @return Boolean
2349          */
2350         public function isDeletedQuick() {
2351                 if ( $this->getNamespace() < 0 ) {
2352                         return false;
2353                 }
2354                 $dbr = wfGetDB( DB_SLAVE );
2355                 $deleted = (bool)$dbr->selectField( 'archive', '1',
2356                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2357                         __METHOD__
2358                 );
2359                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
2360                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
2361                                 array( 'fa_name' => $this->getDBkey() ),
2362                                 __METHOD__
2363                         );
2364                 }
2365                 return $deleted;
2366         }
2367
2368         /**
2369          * Get the article ID for this Title from the link cache,
2370          * adding it if necessary
2371          *
2372          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select
2373          *  for update
2374          * @return Int the ID
2375          */
2376         public function getArticleID( $flags = 0 ) {
2377                 if ( $this->getNamespace() < 0 ) {
2378                         return $this->mArticleID = 0;
2379                 }
2380                 $linkCache = LinkCache::singleton();
2381                 if ( $flags & self::GAID_FOR_UPDATE ) {
2382                         $oldUpdate = $linkCache->forUpdate( true );
2383                         $linkCache->clearLink( $this );
2384                         $this->mArticleID = $linkCache->addLinkObj( $this );
2385                         $linkCache->forUpdate( $oldUpdate );
2386                 } else {
2387                         if ( -1 == $this->mArticleID ) {
2388                                 $this->mArticleID = $linkCache->addLinkObj( $this );
2389                         }
2390                 }
2391                 return $this->mArticleID;
2392         }
2393
2394         /**
2395          * Is this an article that is a redirect page?
2396          * Uses link cache, adding it if necessary
2397          *
2398          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select for update
2399          * @return Bool
2400          */
2401         public function isRedirect( $flags = 0 ) {
2402                 if ( !is_null( $this->mRedirect ) ) {
2403                         return $this->mRedirect;
2404                 }
2405                 # Calling getArticleID() loads the field from cache as needed
2406                 if ( !$this->getArticleID( $flags ) ) {
2407                         return $this->mRedirect = false;
2408                 }
2409                 $linkCache = LinkCache::singleton();
2410                 $this->mRedirect = (bool)$linkCache->getGoodLinkFieldObj( $this, 'redirect' );
2411
2412                 return $this->mRedirect;
2413         }
2414
2415         /**
2416          * What is the length of this page?
2417          * Uses link cache, adding it if necessary
2418          *
2419          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select for update
2420          * @return Int
2421          */
2422         public function getLength( $flags = 0 ) {
2423                 if ( $this->mLength != -1 ) {
2424                         return $this->mLength;
2425                 }
2426                 # Calling getArticleID() loads the field from cache as needed
2427                 if ( !$this->getArticleID( $flags ) ) {
2428                         return $this->mLength = 0;
2429                 }
2430                 $linkCache = LinkCache::singleton();
2431                 $this->mLength = intval( $linkCache->getGoodLinkFieldObj( $this, 'length' ) );
2432
2433                 return $this->mLength;
2434         }
2435
2436         /**
2437          * What is the page_latest field for this page?
2438          *
2439          * @param $flags Int a bit field; may be Title::GAID_FOR_UPDATE to select for update
2440          * @return Int or 0 if the page doesn't exist
2441          */
2442         public function getLatestRevID( $flags = 0 ) {
2443                 if ( $this->mLatestID !== false ) {
2444                         return intval( $this->mLatestID );
2445                 }
2446                 # Calling getArticleID() loads the field from cache as needed
2447                 if ( !$this->getArticleID( $flags ) ) {
2448                         return $this->mLatestID = 0;
2449                 }
2450                 $linkCache = LinkCache::singleton();
2451                 $this->mLatestID = intval( $linkCache->getGoodLinkFieldObj( $this, 'revision' ) );
2452
2453                 return $this->mLatestID;
2454         }
2455
2456         /**
2457          * This clears some fields in this object, and clears any associated
2458          * keys in the "bad links" section of the link cache.
2459          *
2460          * - This is called from Article::doEdit() and Article::insertOn() to allow
2461          * loading of the new page_id. It's also called from
2462          * Article::doDeleteArticle()
2463          *
2464          * @param $newid Int the new Article ID
2465          */
2466         public function resetArticleID( $newid ) {
2467                 $linkCache = LinkCache::singleton();
2468                 $linkCache->clearBadLink( $this->getPrefixedDBkey() );
2469
2470                 if ( $newid === false ) {
2471                         $this->mArticleID = -1;
2472                 } else {
2473                         $this->mArticleID = intval( $newid );
2474                 }
2475                 $this->mRestrictionsLoaded = false;
2476                 $this->mRestrictions = array();
2477                 $this->mRedirect = null;
2478                 $this->mLength = -1;
2479                 $this->mLatestID = false;
2480         }
2481
2482         /**
2483          * Updates page_touched for this page; called from LinksUpdate.php
2484          *
2485          * @return Bool true if the update succeded
2486          */
2487         public function invalidateCache() {
2488                 if ( wfReadOnly() ) {
2489                         return;
2490                 }
2491                 $dbw = wfGetDB( DB_MASTER );
2492                 $success = $dbw->update(
2493                         'page',
2494                         array( 'page_touched' => $dbw->timestamp() ),
2495                         $this->pageCond(),
2496                         __METHOD__
2497                 );
2498                 HTMLFileCache::clearFileCache( $this );
2499                 return $success;
2500         }
2501
2502         /**
2503          * Prefix some arbitrary text with the namespace or interwiki prefix
2504          * of this object
2505          *
2506          * @param $name String the text
2507          * @return String the prefixed text
2508          * @private
2509          */
2510         /* private */ function prefix( $name ) {
2511                 $p = '';
2512                 if ( $this->mInterwiki != '' ) {
2513                         $p = $this->mInterwiki . ':';
2514                 }
2515
2516                 if ( 0 != $this->mNamespace ) {
2517                         $p .= $this->getNsText() . ':';
2518                 }
2519                 return $p . $name;
2520         }
2521
2522         /**
2523          * Returns a simple regex that will match on characters and sequences invalid in titles.
2524          * Note that this doesn't pick up many things that could be wrong with titles, but that
2525          * replacing this regex with something valid will make many titles valid.
2526          *
2527          * @return String regex string
2528          */
2529         static function getTitleInvalidRegex() {
2530                 static $rxTc = false;
2531                 if ( !$rxTc ) {
2532                         # Matching titles will be held as illegal.
2533                         $rxTc = '/' .
2534                                 # Any character not allowed is forbidden...
2535                                 '[^' . Title::legalChars() . ']' .
2536                                 # URL percent encoding sequences interfere with the ability
2537                                 # to round-trip titles -- you can't link to them consistently.
2538                                 '|%[0-9A-Fa-f]{2}' .
2539                                 # XML/HTML character references produce similar issues.
2540                                 '|&[A-Za-z0-9\x80-\xff]+;' .
2541                                 '|&#[0-9]+;' .
2542                                 '|&#x[0-9A-Fa-f]+;' .
2543                                 '/S';
2544                 }
2545
2546                 return $rxTc;
2547         }
2548
2549         /**
2550          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
2551          *
2552          * @param $text String containing title to capitalize
2553          * @param $ns int namespace index, defaults to NS_MAIN
2554          * @return String containing capitalized title
2555          */
2556         public static function capitalize( $text, $ns = NS_MAIN ) {
2557                 global $wgContLang;
2558
2559                 if ( MWNamespace::isCapitalized( $ns ) ) {
2560                         return $wgContLang->ucfirst( $text );
2561                 } else {
2562                         return $text;
2563                 }
2564         }
2565
2566         /**
2567          * Secure and split - main initialisation function for this object
2568          *
2569          * Assumes that mDbkeyform has been set, and is urldecoded
2570          * and uses underscores, but not otherwise munged.  This function
2571          * removes illegal characters, splits off the interwiki and
2572          * namespace prefixes, sets the other forms, and canonicalizes
2573          * everything.
2574          *
2575          * @return Bool true on success
2576          */
2577         private function secureAndSplit() {
2578                 global $wgContLang, $wgLocalInterwiki;
2579
2580                 # Initialisation
2581                 $rxTc = self::getTitleInvalidRegex();
2582
2583                 $this->mInterwiki = $this->mFragment = '';
2584                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
2585
2586                 $dbkey = $this->mDbkeyform;
2587
2588                 # Strip Unicode bidi override characters.
2589                 # Sometimes they slip into cut-n-pasted page titles, where the
2590                 # override chars get included in list displays.
2591                 $dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );
2592
2593                 # Clean up whitespace
2594                 # Note: use of the /u option on preg_replace here will cause
2595                 # input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
2596                 # conveniently disabling them.
2597                 $dbkey = preg_replace( '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u', '_', $dbkey );
2598                 $dbkey = trim( $dbkey, '_' );
2599
2600                 if ( $dbkey == '' ) {
2601                         return false;
2602                 }
2603
2604                 if ( false !== strpos( $dbkey, UTF8_REPLACEMENT ) ) {
2605                         # Contained illegal UTF-8 sequences or forbidden Unicode chars.
2606                         return false;
2607                 }
2608
2609                 $this->mDbkeyform = $dbkey;
2610
2611                 # Initial colon indicates main namespace rather than specified default
2612                 # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
2613                 if ( ':' == $dbkey { 0 } ) {
2614                         $this->mNamespace = NS_MAIN;
2615                         $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
2616                         $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
2617                 }
2618
2619                 # Namespace or interwiki prefix
2620                 $firstPass = true;
2621                 $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
2622                 do {
2623                         $m = array();
2624                         if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
2625                                 $p = $m[1];
2626                                 if ( ( $ns = $wgContLang->getNsIndex( $p ) ) !== false ) {
2627                                         # Ordinary namespace
2628                                         $dbkey = $m[2];
2629                                         $this->mNamespace = $ns;
2630                                         # For Talk:X pages, check if X has a "namespace" prefix
2631                                         if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
2632                                                 if ( $wgContLang->getNsIndex( $x[1] ) ) {
2633                                                         # Disallow Talk:File:x type titles...
2634                                                         return false;
2635                                                 } else if ( Interwiki::isValidInterwiki( $x[1] ) ) {
2636                                                         # Disallow Talk:Interwiki:x type titles...
2637                                                         return false;
2638                                                 }
2639                                         }
2640                                 } elseif ( Interwiki::isValidInterwiki( $p ) ) {
2641                                         if ( !$firstPass ) {
2642                                                 # Can't make a local interwiki link to an interwiki link.
2643                                                 # That's just crazy!
2644                                                 return false;
2645                                         }
2646
2647                                         # Interwiki link
2648                                         $dbkey = $m[2];
2649                                         $this->mInterwiki = $wgContLang->lc( $p );
2650
2651                                         # Redundant interwiki prefix to the local wiki
2652                                         if ( $wgLocalInterwiki !== false
2653                                                 && 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki ) )
2654                                         {
2655                                                 if ( $dbkey == '' ) {
2656                                                         # Can't have an empty self-link
2657                                                         return false;
2658                                                 }
2659                                                 $this->mInterwiki = '';
2660                                                 $firstPass = false;
2661                                                 # Do another namespace split...
2662                                                 continue;
2663                                         }
2664
2665                                         # If there's an initial colon after the interwiki, that also
2666                                         # resets the default namespace
2667                                         if ( $dbkey !== '' && $dbkey[0] == ':' ) {
2668                                                 $this->mNamespace = NS_MAIN;
2669                                                 $dbkey = substr( $dbkey, 1 );
2670                                         }
2671                                 }
2672                                 # If there's no recognized interwiki or namespace,
2673                                 # then let the colon expression be part of the title.
2674                         }
2675                         break;
2676                 } while ( true );
2677
2678                 # We already know that some pages won't be in the database!
2679                 if ( $this->mInterwiki != '' || NS_SPECIAL == $this->mNamespace ) {
2680                         $this->mArticleID = 0;
2681                 }
2682                 $fragment = strstr( $dbkey, '#' );
2683                 if ( false !== $fragment ) {
2684                         $this->setFragment( preg_replace( '/^#_*/', '#', $fragment ) );
2685                         $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
2686                         # remove whitespace again: prevents "Foo_bar_#"
2687                         # becoming "Foo_bar_"
2688                         $dbkey = preg_replace( '/_*$/', '', $dbkey );
2689                 }
2690
2691                 # Reject illegal characters.
2692                 if ( preg_match( $rxTc, $dbkey ) ) {
2693                         return false;
2694                 }
2695
2696                 # Pages with "/./" or "/../" appearing in the URLs will often be un-
2697                 # reachable due to the way web browsers deal with 'relative' URLs.
2698                 # Also, they conflict with subpage syntax.  Forbid them explicitly.
2699                 if ( strpos( $dbkey, '.' ) !== false &&
2700                          ( $dbkey === '.' || $dbkey === '..' ||
2701                            strpos( $dbkey, './' ) === 0  ||
2702                            strpos( $dbkey, '../' ) === 0 ||
2703                            strpos( $dbkey, '/./' ) !== false ||
2704                            strpos( $dbkey, '/../' ) !== false  ||
2705                            substr( $dbkey, -2 ) == '/.' ||
2706                            substr( $dbkey, -3 ) == '/..' ) )
2707                 {
2708                         return false;
2709                 }
2710
2711                 # Magic tilde sequences? Nu-uh!
2712                 if ( strpos( $dbkey, '~~~' ) !== false ) {
2713                         return false;
2714                 }
2715
2716                 # Limit the size of titles to 255 bytes. This is typically the size of the
2717                 # underlying database field. We make an exception for special pages, which
2718                 # don't need to be stored in the database, and may edge over 255 bytes due
2719                 # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
2720                 if ( ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 ) ||
2721                   strlen( $dbkey ) > 512 )
2722                 {
2723                         return false;
2724                 }
2725
2726                 # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
2727                 # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
2728                 # other site might be case-sensitive.
2729                 $this->mUserCaseDBKey = $dbkey;
2730                 if ( $this->mInterwiki == '' ) {
2731                         $dbkey = self::capitalize( $dbkey, $this->mNamespace );
2732                 }
2733
2734                 # Can't make a link to a namespace alone... "empty" local links can only be
2735                 # self-links with a fragment identifier.
2736                 if ( $dbkey == '' && $this->mInterwiki == '' && $this->mNamespace != NS_MAIN ) {
2737                         return false;
2738                 }
2739
2740                 // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
2741                 // IP names are not allowed for accounts, and can only be referring to
2742                 // edits from the IP. Given '::' abbreviations and caps/lowercaps,
2743                 // there are numerous ways to present the same IP. Having sp:contribs scan
2744                 // them all is silly and having some show the edits and others not is
2745                 // inconsistent. Same for talk/userpages. Keep them normalized instead.
2746                 $dbkey = ( $this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK )
2747                         ? IP::sanitizeIP( $dbkey )
2748                         : $dbkey;
2749
2750                 // Any remaining initial :s are illegal.
2751                 if ( $dbkey !== '' && ':' == $dbkey { 0 } ) {
2752                         return false;
2753                 }
2754
2755                 # Fill fields
2756                 $this->mDbkeyform = $dbkey;
2757                 $this->mUrlform = wfUrlencode( $dbkey );
2758
2759                 $this->mTextform = str_replace( '_', ' ', $dbkey );
2760
2761                 return true;
2762         }
2763
2764         /**
2765          * Set the fragment for this title. Removes the first character from the
2766          * specified fragment before setting, so it assumes you're passing it with
2767          * an initial "#".
2768          *
2769          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
2770          * Still in active use privately.
2771          *
2772          * @param $fragment String text
2773          */
2774         public function setFragment( $fragment ) {
2775                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
2776         }
2777
2778         /**
2779          * Get a Title object associated with the talk page of this article
2780          *
2781          * @return Title the object for the talk page
2782          */
2783         public function getTalkPage() {
2784                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
2785         }
2786
2787         /**
2788          * Get a title object associated with the subject page of this
2789          * talk page
2790          *
2791          * @return Title the object for the subject page
2792          */
2793         public function getSubjectPage() {
2794                 // Is this the same title?
2795                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
2796                 if ( $this->getNamespace() == $subjectNS ) {
2797                         return $this;
2798                 }
2799                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
2800         }
2801
2802         /**
2803          * Get an array of Title objects linking to this Title
2804          * Also stores the IDs in the link cache.
2805          *
2806          * WARNING: do not use this function on arbitrary user-supplied titles!
2807          * On heavily-used templates it will max out the memory.
2808          *
2809          * @param $options Array: may be FOR UPDATE
2810          * @param $table String: table name
2811          * @param $prefix String: fields prefix
2812          * @return Array of Title objects linking here
2813          */
2814         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
2815                 $linkCache = LinkCache::singleton();
2816
2817                 if ( count( $options ) > 0 ) {
2818                         $db = wfGetDB( DB_MASTER );
2819                 } else {
2820                         $db = wfGetDB( DB_SLAVE );
2821                 }
2822
2823                 $res = $db->select(
2824                         array( 'page', $table ),
2825                         array( 'page_namespace', 'page_title', 'page_id', 'page_len', 'page_is_redirect', 'page_latest' ),
2826                         array(
2827                                 "{$prefix}_from=page_id",
2828                                 "{$prefix}_namespace" => $this->getNamespace(),
2829                                 "{$prefix}_title"     => $this->getDBkey() ),
2830                         __METHOD__,
2831                         $options
2832                 );
2833
2834                 $retVal = array();
2835                 if ( $db->numRows( $res ) ) {
2836                         foreach ( $res as $row ) {
2837                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
2838                                 if ( $titleObj ) {
2839                                         $linkCache->addGoodLinkObj( $row->page_id, $titleObj, $row->page_len, $row->page_is_redirect, $row->page_latest );
2840                                         $retVal[] = $titleObj;
2841                                 }
2842                         }
2843                 }
2844                 return $retVal;
2845         }
2846
2847         /**
2848          * Get an array of Title objects using this Title as a template
2849          * Also stores the IDs in the link cache.
2850          *
2851          * WARNING: do not use this function on arbitrary user-supplied titles!
2852          * On heavily-used templates it will max out the memory.
2853          *
2854          * @param $options Array: may be FOR UPDATE
2855          * @return Array of Title the Title objects linking here
2856          */
2857         public function getTemplateLinksTo( $options = array() ) {
2858                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
2859         }
2860
2861         /**
2862          * Get an array of Title objects referring to non-existent articles linked from this page
2863          *
2864          * @todo check if needed (used only in SpecialBrokenRedirects.php, and should use redirect table in this case)
2865          * @return Array of Title the Title objects
2866          */
2867         public function getBrokenLinksFrom() {
2868                 if ( $this->getArticleId() == 0 ) {
2869                         # All links from article ID 0 are false positives
2870                         return array();
2871                 }
2872
2873                 $dbr = wfGetDB( DB_SLAVE );
2874                 $res = $dbr->select(
2875                         array( 'page', 'pagelinks' ),
2876                         array( 'pl_namespace', 'pl_title' ),
2877                         array(
2878                                 'pl_from' => $this->getArticleId(),
2879                                 'page_namespace IS NULL'
2880                         ),
2881                         __METHOD__, array(),
2882                         array(
2883                                 'page' => array(
2884                                         'LEFT JOIN',
2885                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
2886                                 )
2887                         )
2888                 );
2889
2890                 $retVal = array();
2891                 foreach ( $res as $row ) {
2892                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
2893                 }
2894                 return $retVal;
2895         }
2896
2897
2898         /**
2899          * Get a list of URLs to purge from the Squid cache when this
2900          * page changes
2901          *
2902          * @return Array of String the URLs
2903          */
2904         public function getSquidURLs() {
2905                 global $wgContLang;
2906
2907                 $urls = array(
2908                         $this->getInternalURL(),
2909                         $this->getInternalURL( 'action=history' )
2910                 );
2911
2912                 // purge variant urls as well
2913                 if ( $wgContLang->hasVariants() ) {
2914                         $variants = $wgContLang->getVariants();
2915                         foreach ( $variants as $vCode ) {
2916                                 $urls[] = $this->getInternalURL( '', $vCode );
2917                         }
2918                 }
2919
2920                 return $urls;
2921         }
2922
2923         /**
2924          * Purge all applicable Squid URLs
2925          */
2926         public function purgeSquid() {
2927                 global $wgUseSquid;
2928                 if ( $wgUseSquid ) {
2929                         $urls = $this->getSquidURLs();
2930                         $u = new SquidUpdate( $urls );
2931                         $u->doUpdate();
2932                 }
2933         }
2934
2935         /**
2936          * Move this page without authentication
2937          *
2938          * @param $nt Title the new page Title
2939          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
2940          */
2941         public function moveNoAuth( &$nt ) {
2942                 return $this->moveTo( $nt, false );
2943         }
2944
2945         /**
2946          * Check whether a given move operation would be valid.
2947          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
2948          *
2949          * @param $nt Title the new title
2950          * @param $auth Bool indicates whether $wgUser's permissions
2951          *  should be checked
2952          * @param $reason String is the log summary of the move, used for spam checking
2953          * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
2954          */
2955         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
2956                 global $wgUser;
2957
2958                 $errors = array();
2959                 if ( !$nt ) {
2960                         // Normally we'd add this to $errors, but we'll get
2961                         // lots of syntax errors if $nt is not an object
2962                         return array( array( 'badtitletext' ) );
2963                 }
2964                 if ( $this->equals( $nt ) ) {
2965                         $errors[] = array( 'selfmove' );
2966                 }
2967                 if ( !$this->isMovable() ) {
2968                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2969                 }
2970                 if ( $nt->getInterwiki() != '' ) {
2971                         $errors[] = array( 'immobile-target-namespace-iw' );
2972                 }
2973                 if ( !$nt->isMovable() ) {
2974                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
2975                 }
2976
2977                 $oldid = $this->getArticleID();
2978                 $newid = $nt->getArticleID();
2979
2980                 if ( strlen( $nt->getDBkey() ) < 1 ) {
2981                         $errors[] = array( 'articleexists' );
2982                 }
2983                 if ( ( $this->getDBkey() == '' ) ||
2984                          ( !$oldid ) ||
2985                          ( $nt->getDBkey() == '' ) ) {
2986                         $errors[] = array( 'badarticleerror' );
2987                 }
2988
2989                 // Image-specific checks
2990                 if ( $this->getNamespace() == NS_FILE ) {
2991                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
2992                 }
2993
2994                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
2995                         $errors[] = array( 'nonfile-cannot-move-to-file' );
2996                 }
2997
2998                 if ( $auth ) {
2999                         $errors = wfMergeErrorArrays( $errors,
3000                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3001                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3002                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3003                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3004                 }
3005
3006                 $match = EditPage::matchSummarySpamRegex( $reason );
3007                 if ( $match !== false ) {
3008                         // This is kind of lame, won't display nice
3009                         $errors[] = array( 'spamprotectiontext' );
3010                 }
3011
3012                 $err = null;
3013                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3014                         $errors[] = array( 'hookaborted', $err );
3015                 }
3016
3017                 # The move is allowed only if (1) the target doesn't exist, or
3018                 # (2) the target is a redirect to the source, and has no history
3019                 # (so we can undo bad moves right after they're done).
3020
3021                 if ( 0 != $newid ) { # Target exists; check for validity
3022                         if ( !$this->isValidMoveTarget( $nt ) ) {
3023                                 $errors[] = array( 'articleexists' );
3024                         }
3025                 } else {
3026                         $tp = $nt->getTitleProtection();
3027                         $right = ( $tp['pt_create_perm'] == 'sysop' ) ? 'protect' : $tp['pt_create_perm'];
3028                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3029                                 $errors[] = array( 'cantmove-titleprotected' );
3030                         }
3031                 }
3032                 if ( empty( $errors ) ) {
3033                         return true;
3034                 }
3035                 return $errors;
3036         }
3037
3038         /**
3039          * Check if the requested move target is a valid file move target
3040          * @param Title $nt Target title
3041          * @return array List of errors
3042          */
3043         protected function validateFileMoveOperation( $nt ) {
3044                 global $wgUser;
3045
3046                 $errors = array();
3047
3048                 if ( $nt->getNamespace() != NS_FILE ) {
3049                         $errors[] = array( 'imagenocrossnamespace' );
3050                 }
3051
3052                 $file = wfLocalFile( $this );
3053                 if ( $file->exists() ) {
3054                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3055                                 $errors[] = array( 'imageinvalidfilename' );
3056                         }
3057                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3058                                 $errors[] = array( 'imagetypemismatch' );
3059                         }
3060                 }
3061
3062                 $destFile = wfLocalFile( $nt );
3063                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3064                         $errors[] = array( 'file-exists-sharedrepo' );
3065                 }
3066
3067                 return $errors;
3068         }
3069
3070         /**
3071          * Move a title to a new location
3072          *
3073          * @param $nt Title the new title
3074          * @param $auth Bool indicates whether $wgUser's permissions
3075          *  should be checked
3076          * @param $reason String the reason for the move
3077          * @param $createRedirect Bool Whether to create a redirect from the old title to the new title.
3078          *  Ignored if the user doesn't have the suppressredirect right.
3079          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3080          */
3081         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3082                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3083                 if ( is_array( $err ) ) {
3084                         return $err;
3085                 }
3086
3087                 // If it is a file, move it first. It is done before all other moving stuff is
3088                 // done because it's hard to revert
3089                 $dbw = wfGetDB( DB_MASTER );
3090                 if ( $this->getNamespace() == NS_FILE ) {
3091                         $file = wfLocalFile( $this );
3092                         if ( $file->exists() ) {
3093                                 $status = $file->move( $nt );
3094                                 if ( !$status->isOk() ) {
3095                                         return $status->getErrorsArray();
3096                                 }
3097                         }
3098                 }
3099
3100                 $dbw->begin(); # If $file was a LocalFile, its transaction would have closed our own.
3101                 $pageid = $this->getArticleID( GAID_FOR_UPDATE );
3102                 $protected = $this->isProtected();
3103                 $pageCountChange = ( $createRedirect ? 1 : 0 ) - ( $nt->exists() ? 1 : 0 );
3104
3105                 // Do the actual move
3106                 $err = $this->moveToInternal( $nt, $reason, $createRedirect );
3107                 if ( is_array( $err ) ) {
3108                         # FIXME: What about the File we have already moved?
3109                         $dbw->rollback();
3110                         return $err;
3111                 }
3112
3113                 $redirid = $this->getArticleID();
3114
3115                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3116                 // cl_timestamp, which may disturb time-based lists on some sites.
3117                 $prefixes = $dbw->select(
3118                         'categorylinks',
3119                         array( 'cl_sortkey_prefix', 'cl_to' ),
3120                         array( 'cl_from' => $pageid ),
3121                         __METHOD__
3122                 );
3123                 foreach ( $prefixes as $prefixRow ) {
3124                         $prefix = $prefixRow->cl_sortkey_prefix;
3125                         $catTo = $prefixRow->cl_to;
3126                         $dbw->update( 'categorylinks',
3127                                 array(
3128                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3129                                                 $nt->getCategorySortkey( $prefix ) ),
3130                                         'cl_timestamp=cl_timestamp' ),
3131                                 array(
3132                                         'cl_from' => $pageid,
3133                                         'cl_to' => $catTo ),
3134                                 __METHOD__
3135                         );
3136                 }
3137
3138                 if ( $protected ) {
3139                         # Protect the redirect title as the title used to be...
3140                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3141                                 array(
3142                                         'pr_page'    => $redirid,
3143                                         'pr_type'    => 'pr_type',
3144                                         'pr_level'   => 'pr_level',
3145                                         'pr_cascade' => 'pr_cascade',
3146                                         'pr_user'    => 'pr_user',
3147                                         'pr_expiry'  => 'pr_expiry'
3148                                 ),
3149                                 array( 'pr_page' => $pageid ),
3150                                 __METHOD__,
3151                                 array( 'IGNORE' )
3152                         );
3153                         # Update the protection log
3154                         $log = new LogPage( 'protect' );
3155                         $comment = wfMsgForContent( 'prot_1movedto2', $this->getPrefixedText(), $nt->getPrefixedText() );
3156                         if ( $reason ) {
3157                                 $comment .= wfMsgForContent( 'colon-separator' ) . $reason;
3158                         }
3159                         $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ) ); // FIXME: $params?
3160                 }
3161
3162                 # Update watchlists
3163                 $oldnamespace = $this->getNamespace() & ~1;
3164                 $newnamespace = $nt->getNamespace() & ~1;
3165                 $oldtitle = $this->getDBkey();
3166                 $newtitle = $nt->getDBkey();
3167
3168                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3169                         WatchedItem::duplicateEntries( $this, $nt );
3170                 }
3171
3172                 # Update search engine
3173                 $u = new SearchUpdate( $pageid, $nt->getPrefixedDBkey() );
3174                 $u->doUpdate();
3175                 $u = new SearchUpdate( $redirid, $this->getPrefixedDBkey(), '' );
3176                 $u->doUpdate();
3177
3178                 $dbw->commit();
3179
3180                 # Update site_stats
3181                 if ( $this->isContentPage() && !$nt->isContentPage() ) {
3182                         # No longer a content page
3183                         # Not viewed, edited, removing
3184                         $u = new SiteStatsUpdate( 0, 1, -1, $pageCountChange );
3185                 } elseif ( !$this->isContentPage() && $nt->isContentPage() ) {
3186                         # Now a content page
3187                         # Not viewed, edited, adding
3188                         $u = new SiteStatsUpdate( 0, 1, + 1, $pageCountChange );
3189                 } elseif ( $pageCountChange ) {
3190                         # Redirect added
3191                         $u = new SiteStatsUpdate( 0, 0, 0, 1 );
3192                 } else {
3193                         # Nothing special
3194                         $u = false;
3195                 }
3196                 if ( $u ) {
3197                         $u->doUpdate();
3198                 }
3199                 # Update message cache for interface messages
3200                 if ( $this->getNamespace() == NS_MEDIAWIKI ) {
3201                         # @bug 17860: old article can be deleted, if this the case,
3202                         # delete it from message cache
3203                         if ( $this->getArticleID() === 0 ) {
3204                                 MessageCache::singleton()->replace( $this->getDBkey(), false );
3205                         } else {
3206                                 $oldarticle = new Article( $this );
3207                                 MessageCache::singleton()->replace( $this->getDBkey(), $oldarticle->getContent() );
3208                         }
3209                 }
3210                 if ( $nt->getNamespace() == NS_MEDIAWIKI ) {
3211                         $newarticle = new Article( $nt );
3212                         MessageCache::singleton()->replace( $nt->getDBkey(), $newarticle->getContent() );
3213                 }
3214
3215                 global $wgUser;
3216                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
3217                 return true;
3218         }
3219
3220         /**
3221          * Move page to a title which is either a redirect to the
3222          * source page or nonexistent
3223          *
3224          * @param $nt Title the page to move to, which should be a redirect or nonexistent
3225          * @param $reason String The reason for the move
3226          * @param $createRedirect Bool Whether to leave a redirect at the old title.  Ignored
3227          *   if the user doesn't have the suppressredirect right
3228          */
3229         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3230                 global $wgUser, $wgContLang;
3231
3232                 $moveOverRedirect = $nt->exists();
3233
3234                 $commentMsg = ( $moveOverRedirect ? '1movedto2_redir' : '1movedto2' );
3235                 $comment = wfMsgForContent( $commentMsg, $this->getPrefixedText(), $nt->getPrefixedText() );
3236
3237                 if ( $reason ) {
3238                         $comment .= wfMsgForContent( 'colon-separator' ) . $reason;
3239                 }
3240                 # Truncate for whole multibyte characters.
3241                 $comment = $wgContLang->truncate( $comment, 255 );
3242
3243                 $oldid = $this->getArticleID();
3244                 $latest = $this->getLatestRevID();
3245
3246                 $oldns = $this->getNamespace();
3247                 $olddbk = $this->getDBkey();
3248
3249                 $dbw = wfGetDB( DB_MASTER );
3250
3251                 if ( $moveOverRedirect ) {
3252                         $rcts = $dbw->timestamp( $nt->getEarliestRevTime() );
3253
3254                         $newid = $nt->getArticleID();
3255                         $newns = $nt->getNamespace();
3256                         $newdbk = $nt->getDBkey();
3257
3258                         # Delete the old redirect. We don't save it to history since
3259                         # by definition if we've got here it's rather uninteresting.
3260                         # We have to remove it so that the next step doesn't trigger
3261                         # a conflict on the unique namespace+title index...
3262                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3263                         if ( !$dbw->cascadingDeletes() ) {
3264                                 $dbw->delete( 'revision', array( 'rev_page' => $newid ), __METHOD__ );
3265                                 global $wgUseTrackbacks;
3266                                 if ( $wgUseTrackbacks ) {
3267                                         $dbw->delete( 'trackbacks', array( 'tb_page' => $newid ), __METHOD__ );
3268                                 }
3269                                 $dbw->delete( 'pagelinks', array( 'pl_from' => $newid ), __METHOD__ );
3270                                 $dbw->delete( 'imagelinks', array( 'il_from' => $newid ), __METHOD__ );
3271                                 $dbw->delete( 'categorylinks', array( 'cl_from' => $newid ), __METHOD__ );
3272                                 $dbw->delete( 'templatelinks', array( 'tl_from' => $newid ), __METHOD__ );
3273                                 $dbw->delete( 'externallinks', array( 'el_from' => $newid ), __METHOD__ );
3274                                 $dbw->delete( 'langlinks', array( 'll_from' => $newid ), __METHOD__ );
3275                                 $dbw->delete( 'redirect', array( 'rd_from' => $newid ), __METHOD__ );
3276                         }
3277                         // If the target page was recently created, it may have an entry in recentchanges still
3278                         $dbw->delete( 'recentchanges',
3279                                 array( 'rc_timestamp' => $rcts, 'rc_namespace' => $newns, 'rc_title' => $newdbk, 'rc_new' => 1 ),
3280                                 __METHOD__
3281                         );
3282                 }
3283
3284                 # Save a null revision in the page's history notifying of the move
3285                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
3286                 if ( !is_object( $nullRevision ) ) {
3287                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3288                 }
3289                 $nullRevId = $nullRevision->insertOn( $dbw );
3290
3291                 $article = new Article( $this );
3292                 wfRunHooks( 'NewRevisionFromEditComplete', array( $article, $nullRevision, $latest, $wgUser ) );
3293
3294                 # Change the name of the target page:
3295                 $dbw->update( 'page',
3296                         /* SET */ array(
3297                                 'page_touched'   => $dbw->timestamp(),
3298                                 'page_namespace' => $nt->getNamespace(),
3299                                 'page_title'     => $nt->getDBkey(),
3300                                 'page_latest'    => $nullRevId,
3301                         ),
3302                         /* WHERE */ array( 'page_id' => $oldid ),
3303                         __METHOD__
3304                 );
3305                 $nt->resetArticleID( $oldid );
3306
3307                 # Recreate the redirect, this time in the other direction.
3308                 if ( $createRedirect || !$wgUser->isAllowed( 'suppressredirect' ) ) {
3309                         $mwRedir = MagicWord::get( 'redirect' );
3310                         $redirectText = $mwRedir->getSynonym( 0 ) . ' [[' . $nt->getPrefixedText() . "]]\n";
3311                         $redirectArticle = new Article( $this );
3312                         $newid = $redirectArticle->insertOn( $dbw );
3313                         $redirectRevision = new Revision( array(
3314                                 'page'    => $newid,
3315                                 'comment' => $comment,
3316                                 'text'    => $redirectText ) );
3317                         $redirectRevision->insertOn( $dbw );
3318                         $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
3319
3320                         wfRunHooks( 'NewRevisionFromEditComplete', array( $redirectArticle, $redirectRevision, false, $wgUser ) );
3321
3322                         # Now, we record the link from the redirect to the new title.
3323                         # It should have no other outgoing links...
3324                         $dbw->delete( 'pagelinks', array( 'pl_from' => $newid ), __METHOD__ );
3325                         $dbw->insert( 'pagelinks',
3326                                 array(
3327                                         'pl_from'      => $newid,
3328                                         'pl_namespace' => $nt->getNamespace(),
3329                                         'pl_title'     => $nt->getDBkey() ),
3330                                 __METHOD__ );
3331                         $redirectSuppressed = false;
3332                 } else {
3333                         // Get rid of old new page entries in Special:NewPages and RC.
3334                         // Needs to be before $this->resetArticleID( 0 ).
3335                         $dbw->delete( 'recentchanges', array(
3336                                         'rc_timestamp' => $dbw->timestamp( $this->getEarliestRevTime() ),
3337                                         'rc_namespace' => $oldns,
3338                                         'rc_title' => $olddbk,
3339                                         'rc_new' => 1
3340                                 ),
3341                                 __METHOD__
3342                         );
3343
3344                         $this->resetArticleID( 0 );
3345                         $redirectSuppressed = true;
3346                 }
3347
3348                 # Log the move
3349                 $log = new LogPage( 'move' );
3350                 $logType = ( $moveOverRedirect ? 'move_redir' : 'move' );
3351                 $log->addEntry( $logType, $this, $reason, array( 1 => $nt->getPrefixedText(), 2 => $redirectSuppressed ) );
3352
3353                 # Purge caches for old and new titles
3354                 if ( $moveOverRedirect ) {
3355                         # A simple purge is enough when moving over a redirect
3356                         $nt->purgeSquid();
3357                 } else {
3358                         # Purge caches as per article creation, including any pages that link to this title
3359                         Article::onArticleCreate( $nt );
3360                 }
3361                 $this->purgeSquid();
3362         }
3363
3364         /**
3365          * Move this page's subpages to be subpages of $nt
3366          *
3367          * @param $nt Title Move target
3368          * @param $auth bool Whether $wgUser's permissions should be checked
3369          * @param $reason string The reason for the move
3370          * @param $createRedirect bool Whether to create redirects from the old subpages to
3371          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3372          * @return mixed array with old page titles as keys, and strings (new page titles) or
3373          *     arrays (errors) as values, or an error array with numeric indices if no pages
3374          *     were moved
3375          */
3376         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3377                 global $wgMaximumMovedPages;
3378                 // Check permissions
3379                 if ( !$this->userCan( 'move-subpages' ) ) {
3380                         return array( 'cant-move-subpages' );
3381                 }
3382                 // Do the source and target namespaces support subpages?
3383                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3384                         return array( 'namespace-nosubpages',
3385                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3386                 }
3387                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3388                         return array( 'namespace-nosubpages',
3389                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3390                 }
3391
3392                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3393                 $retval = array();
3394                 $count = 0;
3395                 foreach ( $subpages as $oldSubpage ) {
3396                         $count++;
3397                         if ( $count > $wgMaximumMovedPages ) {
3398                                 $retval[$oldSubpage->getPrefixedTitle()] =
3399                                                 array( 'movepage-max-pages',
3400                                                         $wgMaximumMovedPages );
3401                                 break;
3402                         }
3403
3404                         // We don't know whether this function was called before
3405                         // or after moving the root page, so check both
3406                         // $this and $nt
3407                         if ( $oldSubpage->getArticleId() == $this->getArticleId() ||
3408                                         $oldSubpage->getArticleID() == $nt->getArticleId() )
3409                         {
3410                                 // When moving a page to a subpage of itself,
3411                                 // don't move it twice
3412                                 continue;
3413                         }
3414                         $newPageName = preg_replace(
3415                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3416                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3417                                         $oldSubpage->getDBkey() );
3418                         if ( $oldSubpage->isTalkPage() ) {
3419                                 $newNs = $nt->getTalkPage()->getNamespace();
3420                         } else {
3421                                 $newNs = $nt->getSubjectPage()->getNamespace();
3422                         }
3423                         # Bug 14385: we need makeTitleSafe because the new page names may
3424                         # be longer than 255 characters.
3425                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3426
3427                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3428                         if ( $success === true ) {
3429                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3430                         } else {
3431                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3432                         }
3433                 }
3434                 return $retval;
3435         }
3436
3437         /**
3438          * Checks if this page is just a one-rev redirect.
3439          * Adds lock, so don't use just for light purposes.
3440          *
3441          * @return Bool
3442          */
3443         public function isSingleRevRedirect() {
3444                 $dbw = wfGetDB( DB_MASTER );
3445                 # Is it a redirect?
3446                 $row = $dbw->selectRow( 'page',
3447                         array( 'page_is_redirect', 'page_latest', 'page_id' ),
3448                         $this->pageCond(),
3449                         __METHOD__,
3450                         array( 'FOR UPDATE' )
3451                 );
3452                 # Cache some fields we may want
3453                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3454                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3455                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3456                 if ( !$this->mRedirect ) {
3457                         return false;
3458                 }
3459                 # Does the article have a history?
3460                 $row = $dbw->selectField( array( 'page', 'revision' ),
3461                         'rev_id',
3462                         array( 'page_namespace' => $this->getNamespace(),
3463                                 'page_title' => $this->getDBkey(),
3464                                 'page_id=rev_page',
3465                                 'page_latest != rev_id'
3466                         ),
3467                         __METHOD__,
3468                         array( 'FOR UPDATE' )
3469                 );
3470                 # Return true if there was no history
3471                 return ( $row === false );
3472         }
3473
3474         /**
3475          * Checks if $this can be moved to a given Title
3476          * - Selects for update, so don't call it unless you mean business
3477          *
3478          * @param $nt Title the new title to check
3479          * @return Bool
3480          */
3481         public function isValidMoveTarget( $nt ) {
3482                 # Is it an existing file?
3483                 if ( $nt->getNamespace() == NS_FILE ) {
3484                         $file = wfLocalFile( $nt );
3485                         if ( $file->exists() ) {
3486                                 wfDebug( __METHOD__ . ": file exists\n" );
3487                                 return false;
3488                         }
3489                 }
3490                 # Is it a redirect with no history?
3491                 if ( !$nt->isSingleRevRedirect() ) {
3492                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3493                         return false;
3494                 }
3495                 # Get the article text
3496                 $rev = Revision::newFromTitle( $nt );
3497                 $text = $rev->getText();
3498                 # Does the redirect point to the source?
3499                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3500                 $m = array();
3501                 if ( preg_match( "/\\[\\[\\s*([^\\]\\|]*)]]/", $text, $m ) ) {
3502                         $redirTitle = Title::newFromText( $m[1] );
3503                         if ( !is_object( $redirTitle ) ||
3504                                 ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3505                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) ) {
3506                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3507                                 return false;
3508                         }
3509                 } else {
3510                         # Fail safe
3511                         wfDebug( __METHOD__ . ": failsafe\n" );
3512                         return false;
3513                 }
3514                 return true;
3515         }
3516
3517         /**
3518          * Can this title be added to a user's watchlist?
3519          *
3520          * @return Bool TRUE or FALSE
3521          */
3522         public function isWatchable() {
3523                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
3524         }
3525
3526         /**
3527          * Get categories to which this Title belongs and return an array of
3528          * categories' names.
3529          *
3530          * @return Array of parents in the form:
3531          *        $parent => $currentarticle
3532          */
3533         public function getParentCategories() {
3534                 global $wgContLang;
3535
3536                 $data = array();
3537
3538                 $titleKey = $this->getArticleId();
3539
3540                 if ( $titleKey === 0 ) {
3541                         return $data;
3542                 }
3543
3544                 $dbr = wfGetDB( DB_SLAVE );
3545
3546                 $res = $dbr->select( 'categorylinks', '*',
3547                         array(
3548                                 'cl_from' => $titleKey,
3549                         ),
3550                         __METHOD__,
3551                         array()
3552                 );
3553
3554                 if ( $dbr->numRows( $res ) > 0 ) {
3555                         foreach ( $res as $row ) {
3556                                 // $data[] = Title::newFromText($wgContLang->getNSText ( NS_CATEGORY ).':'.$row->cl_to);
3557                                 $data[$wgContLang->getNSText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3558                         }
3559                 }
3560                 return $data;
3561         }
3562
3563         /**
3564          * Get a tree of parent categories
3565          *
3566          * @param $children Array with the children in the keys, to check for circular refs
3567          * @return Array Tree of parent categories
3568          */
3569         public function getParentCategoryTree( $children = array() ) {
3570                 $stack = array();
3571                 $parents = $this->getParentCategories();
3572
3573                 if ( $parents ) {
3574                         foreach ( $parents as $parent => $current ) {
3575                                 if ( array_key_exists( $parent, $children ) ) {
3576                                         # Circular reference
3577                                         $stack[$parent] = array();
3578                                 } else {
3579                                         $nt = Title::newFromText( $parent );
3580                                         if ( $nt ) {
3581                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
3582                                         }
3583                                 }
3584                         }
3585                 }
3586
3587                 return $stack;
3588         }
3589
3590         /**
3591          * Get an associative array for selecting this title from
3592          * the "page" table
3593          *
3594          * @return Array suitable for the $where parameter of DB::select()
3595          */
3596         public function pageCond() {
3597                 if ( $this->mArticleID > 0 ) {
3598                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3599                         return array( 'page_id' => $this->mArticleID );
3600                 } else {
3601                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
3602                 }
3603         }
3604
3605         /**
3606          * Get the revision ID of the previous revision
3607          *
3608          * @param $revId Int Revision ID. Get the revision that was before this one.
3609          * @param $flags Int Title::GAID_FOR_UPDATE
3610          * @return Int|Bool Old revision ID, or FALSE if none exists
3611          */
3612         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3613                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3614                 return $db->selectField( 'revision', 'rev_id',
3615                         array(
3616                                 'rev_page' => $this->getArticleId( $flags ),
3617                                 'rev_id < ' . intval( $revId )
3618                         ),
3619                         __METHOD__,
3620                         array( 'ORDER BY' => 'rev_id DESC' )
3621                 );
3622         }
3623
3624         /**
3625          * Get the revision ID of the next revision
3626          *
3627          * @param $revId Int Revision ID. Get the revision that was after this one.
3628          * @param $flags Int Title::GAID_FOR_UPDATE
3629          * @return Int|Bool Next revision ID, or FALSE if none exists
3630          */
3631         public function getNextRevisionID( $revId, $flags = 0 ) {
3632                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3633                 return $db->selectField( 'revision', 'rev_id',
3634                         array(
3635                                 'rev_page' => $this->getArticleId( $flags ),
3636                                 'rev_id > ' . intval( $revId )
3637                         ),
3638                         __METHOD__,
3639                         array( 'ORDER BY' => 'rev_id' )
3640                 );
3641         }
3642
3643         /**
3644          * Get the first revision of the page
3645          *
3646          * @param $flags Int Title::GAID_FOR_UPDATE
3647          * @return Revision|Null if page doesn't exist
3648          */
3649         public function getFirstRevision( $flags = 0 ) {
3650                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3651                 $pageId = $this->getArticleId( $flags );
3652                 if ( !$pageId ) {
3653                         return null;
3654                 }
3655                 $row = $db->selectRow( 'revision', '*',
3656                         array( 'rev_page' => $pageId ),
3657                         __METHOD__,
3658                         array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
3659                 );
3660                 if ( !$row ) {
3661                         return null;
3662                 } else {
3663                         return new Revision( $row );
3664                 }
3665         }
3666
3667         /**
3668          * Check if this is a new page
3669          *
3670          * @return bool
3671          */
3672         public function isNewPage() {
3673                 $dbr = wfGetDB( DB_SLAVE );
3674                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
3675         }
3676
3677         /**
3678          * Get the oldest revision timestamp of this page
3679          *
3680          * @return String: MW timestamp
3681          */
3682         public function getEarliestRevTime() {
3683                 $dbr = wfGetDB( DB_SLAVE );
3684                 if ( $this->exists() ) {
3685                         $min = $dbr->selectField( 'revision',
3686                                 'MIN(rev_timestamp)',
3687                                 array( 'rev_page' => $this->getArticleId() ),
3688                                 __METHOD__ );
3689                         return wfTimestampOrNull( TS_MW, $min );
3690                 }
3691                 return null;
3692         }
3693
3694         /**
3695          * Get the number of revisions between the given revision IDs.
3696          * Used for diffs and other things that really need it.
3697          *
3698          * @param $old Int Revision ID.
3699          * @param $new Int Revision ID.
3700          * @return Int Number of revisions between these IDs.
3701          */
3702         public function countRevisionsBetween( $old, $new ) {
3703                 $dbr = wfGetDB( DB_SLAVE );
3704                 return (int)$dbr->selectField( 'revision', 'count(*)', array(
3705                                 'rev_page' => intval( $this->getArticleId() ),
3706                                 'rev_id > ' . intval( $old ),
3707                                 'rev_id < ' . intval( $new )
3708                         ), __METHOD__
3709                 );
3710         }
3711
3712         /**
3713          * Get the number of authors between the given revision IDs.
3714          * Used for diffs and other things that really need it.
3715          *
3716          * @param $fromRevId Int Revision ID (first before range)
3717          * @param $toRevId Int Revision ID (first after range)
3718          * @param $limit Int Maximum number of authors
3719          * @param $flags Int Title::GAID_FOR_UPDATE
3720          * @return Int
3721          */
3722         public function countAuthorsBetween( $fromRevId, $toRevId, $limit, $flags = 0 ) {
3723                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3724                 $res = $db->select( 'revision', 'DISTINCT rev_user_text',
3725                         array(
3726                                 'rev_page' => $this->getArticleID(),
3727                                 'rev_id > ' . (int)$fromRevId,
3728                                 'rev_id < ' . (int)$toRevId
3729                         ), __METHOD__,
3730                         array( 'LIMIT' => $limit )
3731                 );
3732                 return (int)$db->numRows( $res );
3733         }
3734
3735         /**
3736          * Compare with another title.
3737          *
3738          * @param $title Title
3739          * @return Bool
3740          */
3741         public function equals( Title $title ) {
3742                 // Note: === is necessary for proper matching of number-like titles.
3743                 return $this->getInterwiki() === $title->getInterwiki()
3744                         && $this->getNamespace() == $title->getNamespace()
3745                         && $this->getDBkey() === $title->getDBkey();
3746         }
3747
3748         /**
3749          * Callback for usort() to do title sorts by (namespace, title)
3750          *
3751          * @param $a Title
3752          * @param $b Title
3753          *
3754          * @return Integer: result of string comparison, or namespace comparison
3755          */
3756         public static function compare( $a, $b ) {
3757                 if ( $a->getNamespace() == $b->getNamespace() ) {
3758                         return strcmp( $a->getText(), $b->getText() );
3759                 } else {
3760                         return $a->getNamespace() - $b->getNamespace();
3761                 }
3762         }
3763
3764         /**
3765          * Return a string representation of this title
3766          *
3767          * @return String representation of this title
3768          */
3769         public function __toString() {
3770                 return $this->getPrefixedText();
3771         }
3772
3773         /**
3774          * Check if page exists.  For historical reasons, this function simply
3775          * checks for the existence of the title in the page table, and will
3776          * thus return false for interwiki links, special pages and the like.
3777          * If you want to know if a title can be meaningfully viewed, you should
3778          * probably call the isKnown() method instead.
3779          *
3780          * @return Bool
3781          */
3782         public function exists() {
3783                 return $this->getArticleId() != 0;
3784         }
3785
3786         /**
3787          * Should links to this title be shown as potentially viewable (i.e. as
3788          * "bluelinks"), even if there's no record by this title in the page
3789          * table?
3790          *
3791          * This function is semi-deprecated for public use, as well as somewhat
3792          * misleadingly named.  You probably just want to call isKnown(), which
3793          * calls this function internally.
3794          *
3795          * (ISSUE: Most of these checks are cheap, but the file existence check
3796          * can potentially be quite expensive.  Including it here fixes a lot of
3797          * existing code, but we might want to add an optional parameter to skip
3798          * it and any other expensive checks.)
3799          *
3800          * @return Bool
3801          */
3802         public function isAlwaysKnown() {
3803                 if ( $this->mInterwiki != '' ) {
3804                         return true;  // any interwiki link might be viewable, for all we know
3805                 }
3806                 switch( $this->mNamespace ) {
3807                         case NS_MEDIA:
3808                         case NS_FILE:
3809                                 // file exists, possibly in a foreign repo
3810                                 return (bool)wfFindFile( $this );
3811                         case NS_SPECIAL:
3812                                 // valid special page
3813                                 return SpecialPage::exists( $this->getDBkey() );
3814                         case NS_MAIN:
3815                                 // selflink, possibly with fragment
3816                                 return $this->mDbkeyform == '';
3817                         case NS_MEDIAWIKI:
3818                                 // known system message
3819                                 return $this->getDefaultMessageText() !== false;
3820                         default:
3821                                 return false;
3822                 }
3823         }
3824
3825         /**
3826          * Does this title refer to a page that can (or might) be meaningfully
3827          * viewed?  In particular, this function may be used to determine if
3828          * links to the title should be rendered as "bluelinks" (as opposed to
3829          * "redlinks" to non-existent pages).
3830          *
3831          * @return Bool
3832          */
3833         public function isKnown() {
3834                 return $this->isAlwaysKnown() || $this->exists();
3835         }
3836
3837         /**
3838          * Does this page have source text?
3839          *
3840          * @return Boolean
3841          */
3842         public function hasSourceText() {
3843                 if ( $this->exists() ) {
3844                         return true;
3845                 }
3846
3847                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
3848                         // If the page doesn't exist but is a known system message, default
3849                         // message content will be displayed, same for language subpages
3850                         return $this->getDefaultMessageText() !== false;
3851                 }
3852
3853                 return false;
3854         }
3855
3856         /**
3857          * Get the default message text or false if the message doesn't exist
3858          *
3859          * @return String or false
3860          */
3861         public function getDefaultMessageText() {
3862                 global $wgContLang;
3863
3864                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
3865                         return false;
3866                 }
3867
3868                 list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
3869                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
3870
3871                 if ( $message->exists() ) {
3872                         return $message->plain();
3873                 } else {
3874                         return false;
3875                 }
3876         }
3877
3878         /**
3879          * Is this in a namespace that allows actual pages?
3880          *
3881          * @return Bool
3882          * @internal note -- uses hardcoded namespace index instead of constants
3883          */
3884         public function canExist() {
3885                 return $this->mNamespace >= 0 && $this->mNamespace != NS_MEDIA;
3886         }
3887
3888         /**
3889          * Update page_touched timestamps and send squid purge messages for
3890          * pages linking to this title. May be sent to the job queue depending
3891          * on the number of links. Typically called on create and delete.
3892          */
3893         public function touchLinks() {
3894                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
3895                 $u->doUpdate();
3896
3897                 if ( $this->getNamespace() == NS_CATEGORY ) {
3898                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
3899                         $u->doUpdate();
3900                 }
3901         }
3902
3903         /**
3904          * Get the last touched timestamp
3905          *
3906          * @param $db DatabaseBase: optional db
3907          * @return String last-touched timestamp
3908          */
3909         public function getTouched( $db = null ) {
3910                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
3911                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
3912                 return $touched;
3913         }
3914
3915         /**
3916          * Get the timestamp when this page was updated since the user last saw it.
3917          *
3918          * @param $user User
3919          * @return String|Null
3920          */
3921         public function getNotificationTimestamp( $user = null ) {
3922                 global $wgUser, $wgShowUpdatedMarker;
3923                 // Assume current user if none given
3924                 if ( !$user ) {
3925                         $user = $wgUser;
3926                 }
3927                 // Check cache first
3928                 $uid = $user->getId();
3929                 // avoid isset here, as it'll return false for null entries
3930                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
3931                         return $this->mNotificationTimestamp[$uid];
3932                 }
3933                 if ( !$uid || !$wgShowUpdatedMarker ) {
3934                         return $this->mNotificationTimestamp[$uid] = false;
3935                 }
3936                 // Don't cache too much!
3937                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
3938                         $this->mNotificationTimestamp = array();
3939                 }
3940                 $dbr = wfGetDB( DB_SLAVE );
3941                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
3942                         'wl_notificationtimestamp',
3943                         array( 'wl_namespace' => $this->getNamespace(),
3944                                 'wl_title' => $this->getDBkey(),
3945                                 'wl_user' => $user->getId()
3946                         ),
3947                         __METHOD__
3948                 );
3949                 return $this->mNotificationTimestamp[$uid];
3950         }
3951
3952         /**
3953          * Get the trackback URL for this page
3954          *
3955          * @return String Trackback URL
3956          */
3957         public function trackbackURL() {
3958                 global $wgScriptPath, $wgServer, $wgScriptExtension;
3959
3960                 return "$wgServer$wgScriptPath/trackback$wgScriptExtension?article="
3961                         . htmlspecialchars( urlencode( $this->getPrefixedDBkey() ) );
3962         }
3963
3964         /**
3965          * Get the trackback RDF for this page
3966          *
3967          * @return String Trackback RDF
3968          */
3969         public function trackbackRDF() {
3970                 $url = htmlspecialchars( $this->getFullURL() );
3971                 $title = htmlspecialchars( $this->getText() );
3972                 $tburl = $this->trackbackURL();
3973
3974                 // Autodiscovery RDF is placed in comments so HTML validator
3975                 // won't barf. This is a rather icky workaround, but seems
3976                 // frequently used by this kind of RDF thingy.
3977                 //
3978                 // Spec: http://www.sixapart.com/pronet/docs/trackback_spec
3979                 return "<!--
3980 <rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\"
3981                  xmlns:dc=\"http://purl.org/dc/elements/1.1/\"
3982                  xmlns:trackback=\"http://madskills.com/public/xml/rss/module/trackback/\">
3983 <rdf:Description
3984    rdf:about=\"$url\"
3985    dc:identifier=\"$url\"
3986    dc:title=\"$title\"
3987    trackback:ping=\"$tburl\" />
3988 </rdf:RDF>
3989 -->";
3990         }
3991
3992         /**
3993          * Generate strings used for xml 'id' names in monobook tabs
3994          *
3995          * @param $prepend string defaults to 'nstab-'
3996          * @return String XML 'id' name
3997          */
3998         public function getNamespaceKey( $prepend = 'nstab-' ) {
3999                 global $wgContLang;
4000                 // Gets the subject namespace if this title
4001                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4002                 // Checks if cononical namespace name exists for namespace
4003                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4004                         // Uses canonical namespace name
4005                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4006                 } else {
4007                         // Uses text of namespace
4008                         $namespaceKey = $this->getSubjectNsText();
4009                 }
4010                 // Makes namespace key lowercase
4011                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4012                 // Uses main
4013                 if ( $namespaceKey == '' ) {
4014                         $namespaceKey = 'main';
4015                 }
4016                 // Changes file to image for backwards compatibility
4017                 if ( $namespaceKey == 'file' ) {
4018                         $namespaceKey = 'image';
4019                 }
4020                 return $prepend . $namespaceKey;
4021         }
4022
4023         /**
4024          * Returns true if this is a special page.
4025          *
4026          * @return boolean
4027          */
4028         public function isSpecialPage() {
4029                 return $this->getNamespace() == NS_SPECIAL;
4030         }
4031
4032         /**
4033          * Returns true if this title resolves to the named special page
4034          *
4035          * @param $name String The special page name
4036          * @return boolean
4037          */
4038         public function isSpecial( $name ) {
4039                 if ( $this->getNamespace() == NS_SPECIAL ) {
4040                         list( $thisName, /* $subpage */ ) = SpecialPage::resolveAliasWithSubpage( $this->getDBkey() );
4041                         if ( $name == $thisName ) {
4042                                 return true;
4043                         }
4044                 }
4045                 return false;
4046         }
4047
4048         /**
4049          * If the Title refers to a special page alias which is not the local default, resolve
4050          * the alias, and localise the name as necessary.  Otherwise, return $this
4051          *
4052          * @return Title
4053          */
4054         public function fixSpecialName() {
4055                 if ( $this->getNamespace() == NS_SPECIAL ) {
4056                         $canonicalName = SpecialPage::resolveAlias( $this->mDbkeyform );
4057                         if ( $canonicalName ) {
4058                                 $localName = SpecialPage::getLocalNameFor( $canonicalName );
4059                                 if ( $localName != $this->mDbkeyform ) {
4060                                         return Title::makeTitle( NS_SPECIAL, $localName );
4061                                 }
4062                         }
4063                 }
4064                 return $this;
4065         }
4066
4067         /**
4068          * Is this Title in a namespace which contains content?
4069          * In other words, is this a content page, for the purposes of calculating
4070          * statistics, etc?
4071          *
4072          * @return Boolean
4073          */
4074         public function isContentPage() {
4075                 return MWNamespace::isContent( $this->getNamespace() );
4076         }
4077
4078         /**
4079          * Get all extant redirects to this Title
4080          *
4081          * @param $ns Int|Null Single namespace to consider; NULL to consider all namespaces
4082          * @return Array of Title redirects to this title
4083          */
4084         public function getRedirectsHere( $ns = null ) {
4085                 $redirs = array();
4086
4087                 $dbr = wfGetDB( DB_SLAVE );
4088                 $where = array(
4089                         'rd_namespace' => $this->getNamespace(),
4090                         'rd_title' => $this->getDBkey(),
4091                         'rd_from = page_id'
4092                 );
4093                 if ( !is_null( $ns ) ) {
4094                         $where['page_namespace'] = $ns;
4095                 }
4096
4097                 $res = $dbr->select(
4098                         array( 'redirect', 'page' ),
4099                         array( 'page_namespace', 'page_title' ),
4100                         $where,
4101                         __METHOD__
4102                 );
4103
4104                 foreach ( $res as $row ) {
4105                         $redirs[] = self::newFromRow( $row );
4106                 }
4107                 return $redirs;
4108         }
4109
4110         /**
4111          * Check if this Title is a valid redirect target
4112          *
4113          * @return Bool
4114          */
4115         public function isValidRedirectTarget() {
4116                 global $wgInvalidRedirectTargets;
4117
4118                 // invalid redirect targets are stored in a global array, but explicity disallow Userlogout here
4119                 if ( $this->isSpecial( 'Userlogout' ) ) {
4120                         return false;
4121                 }
4122
4123                 foreach ( $wgInvalidRedirectTargets as $target ) {
4124                         if ( $this->isSpecial( $target ) ) {
4125                                 return false;
4126                         }
4127                 }
4128
4129                 return true;
4130         }
4131
4132         /**
4133          * Get a backlink cache object
4134          *
4135          * @return object BacklinkCache
4136          */
4137         function getBacklinkCache() {
4138                 if ( is_null( $this->mBacklinkCache ) ) {
4139                         $this->mBacklinkCache = new BacklinkCache( $this );
4140                 }
4141                 return $this->mBacklinkCache;
4142         }
4143
4144         /**
4145          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4146          *
4147          * @return Boolean
4148          */
4149         public function canUseNoindex() {
4150                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4151
4152                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4153                         ? $wgContentNamespaces
4154                         : $wgExemptFromUserRobotsControl;
4155
4156                 return !in_array( $this->mNamespace, $bannedNamespaces );
4157
4158         }
4159
4160         /**
4161          * Returns restriction types for the current Title
4162          *
4163          * @return array applicable restriction types
4164          */
4165         public function getRestrictionTypes() {
4166                 if ( $this->getNamespace() == NS_SPECIAL ) {
4167                         return array();
4168                 }
4169
4170                 $types = self::getFilteredRestrictionTypes( $this->exists() );
4171
4172                 if ( $this->getNamespace() != NS_FILE ) {
4173                         # Remove the upload restriction for non-file titles
4174                         $types = array_diff( $types, array( 'upload' ) );
4175                 }
4176
4177                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
4178
4179                 wfDebug( __METHOD__ . ': applicable restriction types for ' .
4180                         $this->getPrefixedText() . ' are ' . implode( ',', $types ) . "\n" );
4181
4182                 return $types;
4183         }
4184         /**
4185          * Get a filtered list of all restriction types supported by this wiki.
4186          * @param bool $exists True to get all restriction types that apply to
4187          * titles that do exist, False for all restriction types that apply to
4188          * titles that do not exist
4189          * @return array
4190          */
4191         public static function getFilteredRestrictionTypes( $exists = true ) {
4192                 global $wgRestrictionTypes;
4193                 $types = $wgRestrictionTypes;
4194                 if ( $exists ) {
4195                         # Remove the create restriction for existing titles
4196                         $types = array_diff( $types, array( 'create' ) );
4197                 } else {
4198                         # Only the create and upload restrictions apply to non-existing titles
4199                         $types = array_intersect( $types, array( 'create', 'upload' ) );
4200                 }
4201                 return $types;
4202         }
4203
4204         /**
4205          * Returns the raw sort key to be used for categories, with the specified
4206          * prefix.  This will be fed to Collation::getSortKey() to get a
4207          * binary sortkey that can be used for actual sorting.
4208          *
4209          * @param $prefix string The prefix to be used, specified using
4210          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4211          *   prefix.
4212          * @return string
4213          */
4214         public function getCategorySortkey( $prefix = '' ) {
4215                 $unprefixed = $this->getText();
4216                 if ( $prefix !== '' ) {
4217                         # Separate with a line feed, so the unprefixed part is only used as
4218                         # a tiebreaker when two pages have the exact same prefix.
4219                         # In UCA, tab is the only character that can sort above LF
4220                         # so we strip both of them from the original prefix.
4221                         $prefix = strtr( $prefix, "\n\t", '  ' );
4222                         return "$prefix\n$unprefixed";
4223                 }
4224                 return $unprefixed;
4225         }
4226 }