includes/Title.php

   1 <?php
   2 /**
   3  * Representation of a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 /**
  26  * Represents a title within MediaWiki.
  27  * Optionally may contain an interwiki designation or namespace.
  28  * @note This class can fetch various kinds of data from the database;
  29  *       however, it does so inefficiently.
  30  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  31  *       and does not rely on global state or the database.
  32  *
  33  * @internal documentation reviewed 15 Mar 2010
  34  */
  35 class Title {
  36         /** @var MapCacheLRU */
  37         static private $titleCache = null;
  38
  39         /**
  40          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  41          * commonly used titles. On a batch operation this can become a memory leak
  42          * if not bounded. After hitting this many titles reset the cache.
  43          */
  44         const CACHE_MAX = 1000;
  45
  46         /**
  47          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  48          * to use the master DB
  49          */
  50         const GAID_FOR_UPDATE = 1;
  51
  52         /**
  53          * @name Private member variables
  54          * Please use the accessor functions instead.
  55          * @private
  56          */
  57         // @{
  58
  59         var $mTextform = '';              // /< Text form (spaces not underscores) of the main part
  60         var $mUrlform = '';               // /< URL-encoded form of the main part
  61         var $mDbkeyform = '';             // /< Main part with underscores
  62         var $mUserCaseDBKey;              // /< DB key with the initial letter in the case specified by the user
  63         var $mNamespace = NS_MAIN;        // /< Namespace index, i.e. one of the NS_xxxx constants
  64         var $mInterwiki = '';             // /< Interwiki prefix
  65         var $mFragment = '';              // /< Title fragment (i.e. the bit after the #)
  66         var $mArticleID = -1;             // /< Article ID, fetched from the link cache on demand
  67         var $mLatestID = false;           // /< ID of most recent revision
  68         var $mContentModel = false;       // /< ID of the page's content model, i.e. one of the CONTENT_MODEL_XXX constants
  69         private $mEstimateRevisions;      // /< Estimated number of revisions; null of not loaded
  70         var $mRestrictions = array();     // /< Array of groups allowed to edit this article
  71         var $mOldRestrictions = false;
  72         var $mCascadeRestriction;         ///< Cascade restrictions on this page to included templates and images?
  73         var $mCascadingRestrictions;      // Caching the results of getCascadeProtectionSources
  74         var $mRestrictionsExpiry = array(); ///< When do the restrictions on this page expire?
  75         var $mHasCascadingRestrictions;   ///< Are cascading restrictions in effect on this page?
  76         var $mCascadeSources;             ///< Where are the cascading restrictions coming from on this page?
  77         var $mRestrictionsLoaded = false; ///< Boolean for initialisation on demand
  78         var $mPrefixedText = null;        ///< Text form including namespace/interwiki, initialised on demand
  79         var $mTitleProtection;            ///< Cached value for getTitleProtection (create protection)
  80         # Don't change the following default, NS_MAIN is hardcoded in several
  81         # places.  See bug 696.
  82         # Zero except in {{transclusion}} tags
  83         var $mDefaultNamespace = NS_MAIN; // /< Namespace index when there is no namespace
  84         var $mWatched = null;             // /< Is $wgUser watching this page? null if unfilled, accessed through userIsWatching()
  85         var $mLength = -1;                // /< The page length, 0 for special pages
  86         var $mRedirect = null;            // /< Is the article at this title a redirect?
  87         var $mNotificationTimestamp = array(); // /< Associative array of user ID -> timestamp/false
  88         var $mHasSubpage;                 // /< Whether a page has any subpages
  89         private $mPageLanguage = false;   // /< The (string) language code of the page's language and content code.
  90         private $mTitleValue = null;      // /< A corresponding TitleValue object
  91         // @}
  92
  93         /**
  94          * B/C kludge: provide a TitleParser for use by Title.
  95          * Ideally, Title would have no methods that need this.
  96          * Avoid usage of this singleton by using TitleValue
  97          * and the associated services when possible.
  98          *
  99          * @return TitleParser
 100          */
 101         private static function getTitleParser() {
 102                 global $wgContLang, $wgLocalInterwikis;
 103
 104                 static $titleCodec = null;
 105                 static $titleCodecFingerprint = null;
 106
 107                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 108                 // make sure we are using the right one. To detect changes over the course
 109                 // of a request, we remember a fingerprint of the config used to create the
 110                 // codec singleton, and re-create it if the fingerprint doesn't match.
 111                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . join( '+', $wgLocalInterwikis );
 112
 113                 if ( $fingerprint !== $titleCodecFingerprint ) {
 114                         $titleCodec = null;
 115                 }
 116
 117                 if ( !$titleCodec ) {
 118                         $titleCodec = new MediaWikiTitleCodec( $wgContLang, GenderCache::singleton(), $wgLocalInterwikis );
 119                         $titleCodecFingerprint = $fingerprint;
 120                 }
 121
 122                 return $titleCodec;
 123         }
 124
 125         /**
 126          * B/C kludge: provide a TitleParser for use by Title.
 127          * Ideally, Title would have no methods that need this.
 128          * Avoid usage of this singleton by using TitleValue
 129          * and the associated services when possible.
 130          *
 131          * @return TitleFormatter
 132          */
 133         private static function getTitleFormatter() {
 134                 //NOTE: we know that getTitleParser() returns a MediaWikiTitleCodec,
 135                 //      which implements TitleFormatter.
 136                 return self::getTitleParser();
 137         }
 138
 139         /**
 140          * Constructor
 141          */
 142         /*protected*/ function __construct() { }
 143
 144         /**
 145          * Create a new Title from a prefixed DB key
 146          *
 147          * @param string $key the database key, which has underscores
 148          *      instead of spaces, possibly including namespace and
 149          *      interwiki prefixes
 150          * @return Title, or NULL on an error
 151          */
 152         public static function newFromDBkey( $key ) {
 153                 $t = new Title();
 154                 $t->mDbkeyform = $key;
 155                 if ( $t->secureAndSplit() ) {
 156                         return $t;
 157                 } else {
 158                         return null;
 159                 }
 160         }
 161
 162         /**
 163          * Create a new Title from a TitleValue
 164          *
 165          * @param TitleValue $titleValue, assumed to be safe.
 166          *
 167          * @return Title
 168          */
 169         public static function newFromTitleValue( TitleValue $titleValue ) {
 170                 return self::makeTitle(
 171                         $titleValue->getNamespace(),
 172                         $titleValue->getText(),
 173                         $titleValue->getFragment() );
 174         }
 175
 176         /**
 177          * Create a new Title from text, such as what one would find in a link. De-
 178          * codes any HTML entities in the text.
 179          *
 180          * @param string $text the link text; spaces, prefixes, and an
 181          *   initial ':' indicating the main namespace are accepted.
 182          * @param int $defaultNamespace the namespace to use if none is specified
 183          *   by a prefix.  If you want to force a specific namespace even if
 184          *   $text might begin with a namespace prefix, use makeTitle() or
 185          *   makeTitleSafe().
 186          * @throws MWException
 187          * @return Title|null - Title or null on an error.
 188          */
 189         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 190                 if ( is_object( $text ) ) {
 191                         throw new MWException( 'Title::newFromText given an object' );
 192                 }
 193
 194                 $cache = self::getTitleCache();
 195
 196                 /**
 197                  * Wiki pages often contain multiple links to the same page.
 198                  * Title normalization and parsing can become expensive on
 199                  * pages with many links, so we can save a little time by
 200                  * caching them.
 201                  *
 202                  * In theory these are value objects and won't get changed...
 203                  */
 204                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 205                         return $cache->get( $text );
 206                 }
 207
 208                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 209                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 210
 211                 $t = new Title();
 212                 $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
 213                 $t->mDefaultNamespace = intval( $defaultNamespace );
 214
 215                 if ( $t->secureAndSplit() ) {
 216                         if ( $defaultNamespace == NS_MAIN ) {
 217                                 $cache->set( $text, $t );
 218                         }
 219                         return $t;
 220                 } else {
 221                         $ret = null;
 222                         return $ret;
 223                 }
 224         }
 225
 226         /**
 227          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 228          *
 229          * Example of wrong and broken code:
 230          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 231          *
 232          * Example of right code:
 233          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 234          *
 235          * Create a new Title from URL-encoded text. Ensures that
 236          * the given title's length does not exceed the maximum.
 237          *
 238          * @param string $url the title, as might be taken from a URL
 239          * @return Title the new object, or NULL on an error
 240          */
 241         public static function newFromURL( $url ) {
 242                 $t = new Title();
 243
 244                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 245                 # but some URLs used it as a space replacement and they still come
 246                 # from some external search tools.
 247                 if ( strpos( self::legalChars(), '+' ) === false ) {
 248                         $url = str_replace( '+', ' ', $url );
 249                 }
 250
 251                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 252                 if ( $t->secureAndSplit() ) {
 253                         return $t;
 254                 } else {
 255                         return null;
 256                 }
 257         }
 258
 259         /**
 260          * @return MapCacheLRU
 261          */
 262         private static function getTitleCache() {
 263                 if ( self::$titleCache == null ) {
 264                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 265                 }
 266                 return self::$titleCache;
 267         }
 268
 269         /**
 270          * Returns a list of fields that are to be selected for initializing Title objects or LinkCache entries.
 271          * Uses $wgContentHandlerUseDB to determine whether to include page_content_model.
 272          *
 273          * @return array
 274          */
 275         protected static function getSelectFields() {
 276                 global $wgContentHandlerUseDB;
 277
 278                 $fields = array(
 279                         'page_namespace', 'page_title', 'page_id',
 280                         'page_len', 'page_is_redirect', 'page_latest',
 281                 );
 282
 283                 if ( $wgContentHandlerUseDB ) {
 284                         $fields[] = 'page_content_model';
 285                 }
 286
 287                 return $fields;
 288         }
 289
 290         /**
 291          * Create a new Title from an article ID
 292          *
 293          * @param int $id the page_id corresponding to the Title to create
 294          * @param int $flags use Title::GAID_FOR_UPDATE to use master
 295          * @return Title|null the new object, or NULL on an error
 296          */
 297         public static function newFromID( $id, $flags = 0 ) {
 298                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 299                 $row = $db->selectRow(
 300                         'page',
 301                         self::getSelectFields(),
 302                         array( 'page_id' => $id ),
 303                         __METHOD__
 304                 );
 305                 if ( $row !== false ) {
 306                         $title = Title::newFromRow( $row );
 307                 } else {
 308                         $title = null;
 309                 }
 310                 return $title;
 311         }
 312
 313         /**
 314          * Make an array of titles from an array of IDs
 315          *
 316          * @param array $ids of Int Array of IDs
 317          * @return Array of Titles
 318          */
 319         public static function newFromIDs( $ids ) {
 320                 if ( !count( $ids ) ) {
 321                         return array();
 322                 }
 323                 $dbr = wfGetDB( DB_SLAVE );
 324
 325                 $res = $dbr->select(
 326                         'page',
 327                         self::getSelectFields(),
 328                         array( 'page_id' => $ids ),
 329                         __METHOD__
 330                 );
 331
 332                 $titles = array();
 333                 foreach ( $res as $row ) {
 334                         $titles[] = Title::newFromRow( $row );
 335                 }
 336                 return $titles;
 337         }
 338
 339         /**
 340          * Make a Title object from a DB row
 341          *
 342          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 343          * @return Title corresponding Title
 344          */
 345         public static function newFromRow( $row ) {
 346                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 347                 $t->loadFromRow( $row );
 348                 return $t;
 349         }
 350
 351         /**
 352          * Load Title object fields from a DB row.
 353          * If false is given, the title will be treated as non-existing.
 354          *
 355          * @param $row stdClass|bool database row
 356          */
 357         public function loadFromRow( $row ) {
 358                 if ( $row ) { // page found
 359                         if ( isset( $row->page_id ) ) {
 360                                 $this->mArticleID = (int)$row->page_id;
 361                         }
 362                         if ( isset( $row->page_len ) ) {
 363                                 $this->mLength = (int)$row->page_len;
 364                         }
 365                         if ( isset( $row->page_is_redirect ) ) {
 366                                 $this->mRedirect = (bool)$row->page_is_redirect;
 367                         }
 368                         if ( isset( $row->page_latest ) ) {
 369                                 $this->mLatestID = (int)$row->page_latest;
 370                         }
 371                         if ( isset( $row->page_content_model ) ) {
 372                                 $this->mContentModel = strval( $row->page_content_model );
 373                         } else {
 374                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 375                         }
 376                 } else { // page not found
 377                         $this->mArticleID = 0;
 378                         $this->mLength = 0;
 379                         $this->mRedirect = false;
 380                         $this->mLatestID = 0;
 381                         $this->mContentModel = false; # initialized lazily in getContentModel()
 382                 }
 383         }
 384
 385         /**
 386          * Create a new Title from a namespace index and a DB key.
 387          * It's assumed that $ns and $title are *valid*, for instance when
 388          * they came directly from the database or a special page name.
 389          * For convenience, spaces are converted to underscores so that
 390          * eg user_text fields can be used directly.
 391          *
 392          * @param int $ns the namespace of the article
 393          * @param string $title the unprefixed database key form
 394          * @param string $fragment the link fragment (after the "#")
 395          * @param string $interwiki the interwiki prefix
 396          * @return Title the new object
 397          */
 398         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 399                 $t = new Title();
 400                 $t->mInterwiki = $interwiki;
 401                 $t->mFragment = $fragment;
 402                 $t->mNamespace = $ns = intval( $ns );
 403                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 404                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 405                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 406                 $t->mTextform = str_replace( '_', ' ', $title );
 407                 $t->mContentModel = false; # initialized lazily in getContentModel()
 408                 return $t;
 409         }
 410
 411         /**
 412          * Create a new Title from a namespace index and a DB key.
 413          * The parameters will be checked for validity, which is a bit slower
 414          * than makeTitle() but safer for user-provided data.
 415          *
 416          * @param int $ns the namespace of the article
 417          * @param string $title database key form
 418          * @param string $fragment the link fragment (after the "#")
 419          * @param string $interwiki interwiki prefix
 420          * @return Title the new object, or NULL on an error
 421          */
 422         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 423                 if ( !MWNamespace::exists( $ns ) ) {
 424                         return null;
 425                 }
 426
 427                 $t = new Title();
 428                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 429                 if ( $t->secureAndSplit() ) {
 430                         return $t;
 431                 } else {
 432                         return null;
 433                 }
 434         }
 435
 436         /**
 437          * Create a new Title for the Main Page
 438          *
 439          * @return Title the new object
 440          */
 441         public static function newMainPage() {
 442                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 443                 // Don't give fatal errors if the message is broken
 444                 if ( !$title ) {
 445                         $title = Title::newFromText( 'Main Page' );
 446                 }
 447                 return $title;
 448         }
 449
 450         /**
 451          * Extract a redirect destination from a string and return the
 452          * Title, or null if the text doesn't contain a valid redirect
 453          * This will only return the very next target, useful for
 454          * the redirect table and other checks that don't need full recursion
 455          *
 456          * @param string $text Text with possible redirect
 457          * @return Title: The corresponding Title
 458          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 459          */
 460         public static function newFromRedirect( $text ) {
 461                 ContentHandler::deprecated( __METHOD__, '1.21' );
 462
 463                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 464                 return $content->getRedirectTarget();
 465         }
 466
 467         /**
 468          * Extract a redirect destination from a string and return the
 469          * Title, or null if the text doesn't contain a valid redirect
 470          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 471          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 472          *
 473          * @param string $text Text with possible redirect
 474          * @return Title
 475          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 476          */
 477         public static function newFromRedirectRecurse( $text ) {
 478                 ContentHandler::deprecated( __METHOD__, '1.21' );
 479
 480                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 481                 return $content->getUltimateRedirectTarget();
 482         }
 483
 484         /**
 485          * Extract a redirect destination from a string and return an
 486          * array of Titles, or null if the text doesn't contain a valid redirect
 487          * The last element in the array is the final destination after all redirects
 488          * have been resolved (up to $wgMaxRedirects times)
 489          *
 490          * @param string $text Text with possible redirect
 491          * @return Array of Titles, with the destination last
 492          * @deprecated since 1.21, use Content::getRedirectChain instead.
 493          */
 494         public static function newFromRedirectArray( $text ) {
 495                 ContentHandler::deprecated( __METHOD__, '1.21' );
 496
 497                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 498                 return $content->getRedirectChain();
 499         }
 500
 501         /**
 502          * Get the prefixed DB key associated with an ID
 503          *
 504          * @param int $id the page_id of the article
 505          * @return Title an object representing the article, or NULL if no such article was found
 506          */
 507         public static function nameOf( $id ) {
 508                 $dbr = wfGetDB( DB_SLAVE );
 509
 510                 $s = $dbr->selectRow(
 511                         'page',
 512                         array( 'page_namespace', 'page_title' ),
 513                         array( 'page_id' => $id ),
 514                         __METHOD__
 515                 );
 516                 if ( $s === false ) {
 517                         return null;
 518                 }
 519
 520                 $n = self::makeName( $s->page_namespace, $s->page_title );
 521                 return $n;
 522         }
 523
 524         /**
 525          * Get a regex character class describing the legal characters in a link
 526          *
 527          * @return String the list of characters, not delimited
 528          */
 529         public static function legalChars() {
 530                 global $wgLegalTitleChars;
 531                 return $wgLegalTitleChars;
 532         }
 533
 534         /**
 535          * Returns a simple regex that will match on characters and sequences invalid in titles.
 536          * Note that this doesn't pick up many things that could be wrong with titles, but that
 537          * replacing this regex with something valid will make many titles valid.
 538          *
 539          * @todo: move this into MediaWikiTitleCodec
 540          *
 541          * @return String regex string
 542          */
 543         static function getTitleInvalidRegex() {
 544                 static $rxTc = false;
 545                 if ( !$rxTc ) {
 546                         # Matching titles will be held as illegal.
 547                         $rxTc = '/' .
 548                                 # Any character not allowed is forbidden...
 549                                 '[^' . self::legalChars() . ']' .
 550                                 # URL percent encoding sequences interfere with the ability
 551                                 # to round-trip titles -- you can't link to them consistently.
 552                                 '|%[0-9A-Fa-f]{2}' .
 553                                 # XML/HTML character references produce similar issues.
 554                                 '|&[A-Za-z0-9\x80-\xff]+;' .
 555                                 '|&#[0-9]+;' .
 556                                 '|&#x[0-9A-Fa-f]+;' .
 557                                 '/S';
 558                 }
 559
 560                 return $rxTc;
 561         }
 562
 563         /**
 564          * Utility method for converting a character sequence from bytes to Unicode.
 565          *
 566          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 567          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 568          *
 569          * @param string $byteClass
 570          * @return string
 571          */
 572         public static function convertByteClassToUnicodeClass( $byteClass ) {
 573                 $length = strlen( $byteClass );
 574                 // Input token queue
 575                 $x0 = $x1 = $x2 = '';
 576                 // Decoded queue
 577                 $d0 = $d1 = $d2 = '';
 578                 // Decoded integer codepoints
 579                 $ord0 = $ord1 = $ord2 = 0;
 580                 // Re-encoded queue
 581                 $r0 = $r1 = $r2 = '';
 582                 // Output
 583                 $out = '';
 584                 // Flags
 585                 $allowUnicode = false;
 586                 for ( $pos = 0; $pos < $length; $pos++ ) {
 587                         // Shift the queues down
 588                         $x2 = $x1;
 589                         $x1 = $x0;
 590                         $d2 = $d1;
 591                         $d1 = $d0;
 592                         $ord2 = $ord1;
 593                         $ord1 = $ord0;
 594                         $r2 = $r1;
 595                         $r1 = $r0;
 596                         // Load the current input token and decoded values
 597                         $inChar = $byteClass[$pos];
 598                         if ( $inChar == '\\' ) {
 599                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 600                                         $x0 = $inChar . $m[0];
 601                                         $d0 = chr( hexdec( $m[1] ) );
 602                                         $pos += strlen( $m[0] );
 603                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 604                                         $x0 = $inChar . $m[0];
 605                                         $d0 = chr( octdec( $m[0] ) );
 606                                         $pos += strlen( $m[0] );
 607                                 } elseif ( $pos + 1 >= $length ) {
 608                                         $x0 = $d0 = '\\';
 609                                 } else {
 610                                         $d0 = $byteClass[$pos + 1];
 611                                         $x0 = $inChar . $d0;
 612                                         $pos += 1;
 613                                 }
 614                         } else {
 615                                 $x0 = $d0 = $inChar;
 616                         }
 617                         $ord0 = ord( $d0 );
 618                         // Load the current re-encoded value
 619                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 620                                 $r0 = sprintf( '\x%02x', $ord0 );
 621                         } elseif ( $ord0 >= 0x80 ) {
 622                                 // Allow unicode if a single high-bit character appears
 623                                 $r0 = sprintf( '\x%02x', $ord0 );
 624                                 $allowUnicode = true;
 625                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 626                                 $r0 = '\\' . $d0;
 627                         } else {
 628                                 $r0 = $d0;
 629                         }
 630                         // Do the output
 631                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 632                                 // Range
 633                                 if ( $ord2 > $ord0 ) {
 634                                         // Empty range
 635                                 } elseif ( $ord0 >= 0x80 ) {
 636                                         // Unicode range
 637                                         $allowUnicode = true;
 638                                         if ( $ord2 < 0x80 ) {
 639                                                 // Keep the non-unicode section of the range
 640                                                 $out .= "$r2-\\x7F";
 641                                         }
 642                                 } else {
 643                                         // Normal range
 644                                         $out .= "$r2-$r0";
 645                                 }
 646                                 // Reset state to the initial value
 647                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 648                         } elseif ( $ord2 < 0x80 ) {
 649                                 // ASCII character
 650                                 $out .= $r2;
 651                         }
 652                 }
 653                 if ( $ord1 < 0x80 ) {
 654                         $out .= $r1;
 655                 }
 656                 if ( $ord0 < 0x80 ) {
 657                         $out .= $r0;
 658                 }
 659                 if ( $allowUnicode ) {
 660                         $out .= '\u0080-\uFFFF';
 661                 }
 662                 return $out;
 663         }
 664
 665         /**
 666          * Make a prefixed DB key from a DB key and a namespace index
 667          *
 668          * @param int $ns numerical representation of the namespace
 669          * @param string $title the DB key form the title
 670          * @param string $fragment The link fragment (after the "#")
 671          * @param string $interwiki The interwiki prefix
 672          * @return String the prefixed form of the title
 673          */
 674         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 675                 global $wgContLang;
 676
 677                 $namespace = $wgContLang->getNsText( $ns );
 678                 $name = $namespace == '' ? $title : "$namespace:$title";
 679                 if ( strval( $interwiki ) != '' ) {
 680                         $name = "$interwiki:$name";
 681                 }
 682                 if ( strval( $fragment ) != '' ) {
 683                         $name .= '#' . $fragment;
 684                 }
 685                 return $name;
 686         }
 687
 688         /**
 689          * Escape a text fragment, say from a link, for a URL
 690          *
 691          * @param string $fragment containing a URL or link fragment (after the "#")
 692          * @return String: escaped string
 693          */
 694         static function escapeFragmentForURL( $fragment ) {
 695                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 696                 # fragments appear not to work in IE (at least up to 7) or in at least
 697                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 698                 # to care if they aren't encoded.
 699                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 700         }
 701
 702         /**
 703          * Callback for usort() to do title sorts by (namespace, title)
 704          *
 705          * @param $a Title
 706          * @param $b Title
 707          *
 708          * @return Integer: result of string comparison, or namespace comparison
 709          */
 710         public static function compare( $a, $b ) {
 711                 if ( $a->getNamespace() == $b->getNamespace() ) {
 712                         return strcmp( $a->getText(), $b->getText() );
 713                 } else {
 714                         return $a->getNamespace() - $b->getNamespace();
 715                 }
 716         }
 717
 718         /**
 719          * Determine whether the object refers to a page within
 720          * this project.
 721          *
 722          * @return Bool TRUE if this is an in-project interwiki link or a wikilink, FALSE otherwise
 723          */
 724         public function isLocal() {
 725                 if ( $this->isExternal() ) {
 726                         $iw = Interwiki::fetch( $this->mInterwiki );
 727                         if ( $iw ) {
 728                                 return $iw->isLocal();
 729                         }
 730                 }
 731                 return true;
 732         }
 733
 734         /**
 735          * Is this Title interwiki?
 736          *
 737          * @return Bool
 738          */
 739         public function isExternal() {
 740                 return $this->mInterwiki !== '';
 741         }
 742
 743         /**
 744          * Get the interwiki prefix
 745          *
 746          * Use Title::isExternal to check if a interwiki is set
 747          *
 748          * @return String Interwiki prefix
 749          */
 750         public function getInterwiki() {
 751                 return $this->mInterwiki;
 752         }
 753
 754         /**
 755          * Determine whether the object refers to a page within
 756          * this project and is transcludable.
 757          *
 758          * @return Bool TRUE if this is transcludable
 759          */
 760         public function isTrans() {
 761                 if ( !$this->isExternal() ) {
 762                         return false;
 763                 }
 764
 765                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 766         }
 767
 768         /**
 769          * Returns the DB name of the distant wiki which owns the object.
 770          *
 771          * @return String the DB name
 772          */
 773         public function getTransWikiID() {
 774                 if ( !$this->isExternal() ) {
 775                         return false;
 776                 }
 777
 778                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 779         }
 780
 781         /**
 782          * Get a TitleValue object representing this Title.
 783          *
 784          * @note: Not all valid Titles have a corresponding valid TitleValue
 785          * (e.g. TitleValues cannot represent page-local links that have a
 786          * fragment but no title text).
 787          *
 788          * @return TitleValue|null
 789          */
 790         public function getTitleValue() {
 791                 if ( $this->mTitleValue === null ) {
 792                         try {
 793                                 $this->mTitleValue = new TitleValue(
 794                                         $this->getNamespace(),
 795                                         $this->getDBkey(),
 796                                         $this->getFragment() );
 797                         } catch ( InvalidArgumentException $ex ) {
 798                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 799                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 800                         }
 801                 }
 802
 803                 return $this->mTitleValue;
 804         }
 805
 806         /**
 807          * Get the text form (spaces not underscores) of the main part
 808          *
 809          * @return String Main part of the title
 810          */
 811         public function getText() {
 812                 return $this->mTextform;
 813         }
 814
 815         /**
 816          * Get the URL-encoded form of the main part
 817          *
 818          * @return String Main part of the title, URL-encoded
 819          */
 820         public function getPartialURL() {
 821                 return $this->mUrlform;
 822         }
 823
 824         /**
 825          * Get the main part with underscores
 826          *
 827          * @return String: Main part of the title, with underscores
 828          */
 829         public function getDBkey() {
 830                 return $this->mDbkeyform;
 831         }
 832
 833         /**
 834          * Get the DB key with the initial letter case as specified by the user
 835          *
 836          * @return String DB key
 837          */
 838         function getUserCaseDBKey() {
 839                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 840                         return $this->mUserCaseDBKey;
 841                 } else {
 842                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 843                         return $this->mDbkeyform;
 844                 }
 845         }
 846
 847         /**
 848          * Get the namespace index, i.e. one of the NS_xxxx constants.
 849          *
 850          * @return Integer: Namespace index
 851          */
 852         public function getNamespace() {
 853                 return $this->mNamespace;
 854         }
 855
 856         /**
 857          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 858          *
 859          * @throws MWException
 860          * @return String: Content model id
 861          */
 862         public function getContentModel() {
 863                 if ( !$this->mContentModel ) {
 864                         $linkCache = LinkCache::singleton();
 865                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 866                 }
 867
 868                 if ( !$this->mContentModel ) {
 869                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 870                 }
 871
 872                 if ( !$this->mContentModel ) {
 873                         throw new MWException( 'Failed to determine content model!' );
 874                 }
 875
 876                 return $this->mContentModel;
 877         }
 878
 879         /**
 880          * Convenience method for checking a title's content model name
 881          *
 882          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 883          * @return Boolean true if $this->getContentModel() == $id
 884          */
 885         public function hasContentModel( $id ) {
 886                 return $this->getContentModel() == $id;
 887         }
 888
 889         /**
 890          * Get the namespace text
 891          *
 892          * @return String: Namespace text
 893          */
 894         public function getNsText() {
 895                 if ( $this->isExternal() ) {
 896                         // This probably shouldn't even happen. ohh man, oh yuck.
 897                         // But for interwiki transclusion it sometimes does.
 898                         // Shit. Shit shit shit.
 899                         //
 900                         // Use the canonical namespaces if possible to try to
 901                         // resolve a foreign namespace.
 902                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 903                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 904                         }
 905                 }
 906
 907                 try {
 908                         $formatter = $this->getTitleFormatter();
 909                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
 910                 } catch ( InvalidArgumentException $ex )  {
 911                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
 912                         return false;
 913                 }
 914         }
 915
 916         /**
 917          * Get the namespace text of the subject (rather than talk) page
 918          *
 919          * @return String Namespace text
 920          */
 921         public function getSubjectNsText() {
 922                 global $wgContLang;
 923                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 924         }
 925
 926         /**
 927          * Get the namespace text of the talk page
 928          *
 929          * @return String Namespace text
 930          */
 931         public function getTalkNsText() {
 932                 global $wgContLang;
 933                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
 934         }
 935
 936         /**
 937          * Could this title have a corresponding talk page?
 938          *
 939          * @return Bool TRUE or FALSE
 940          */
 941         public function canTalk() {
 942                 return MWNamespace::canTalk( $this->mNamespace );
 943         }
 944
 945         /**
 946          * Is this in a namespace that allows actual pages?
 947          *
 948          * @return Bool
 949          * @internal note -- uses hardcoded namespace index instead of constants
 950          */
 951         public function canExist() {
 952                 return $this->mNamespace >= NS_MAIN;
 953         }
 954
 955         /**
 956          * Can this title be added to a user's watchlist?
 957          *
 958          * @return Bool TRUE or FALSE
 959          */
 960         public function isWatchable() {
 961                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
 962         }
 963
 964         /**
 965          * Returns true if this is a special page.
 966          *
 967          * @return boolean
 968          */
 969         public function isSpecialPage() {
 970                 return $this->getNamespace() == NS_SPECIAL;
 971         }
 972
 973         /**
 974          * Returns true if this title resolves to the named special page
 975          *
 976          * @param string $name The special page name
 977          * @return boolean
 978          */
 979         public function isSpecial( $name ) {
 980                 if ( $this->isSpecialPage() ) {
 981                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
 982                         if ( $name == $thisName ) {
 983                                 return true;
 984                         }
 985                 }
 986                 return false;
 987         }
 988
 989         /**
 990          * If the Title refers to a special page alias which is not the local default, resolve
 991          * the alias, and localise the name as necessary.  Otherwise, return $this
 992          *
 993          * @return Title
 994          */
 995         public function fixSpecialName() {
 996                 if ( $this->isSpecialPage() ) {
 997                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
 998                         if ( $canonicalName ) {
 999                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1000                                 if ( $localName != $this->mDbkeyform ) {
1001                                         return Title::makeTitle( NS_SPECIAL, $localName );
1002                                 }
1003                         }
1004                 }
1005                 return $this;
1006         }
1007
1008         /**
1009          * Returns true if the title is inside the specified namespace.
1010          *
1011          * Please make use of this instead of comparing to getNamespace()
1012          * This function is much more resistant to changes we may make
1013          * to namespaces than code that makes direct comparisons.
1014          * @param int $ns The namespace
1015          * @return bool
1016          * @since 1.19
1017          */
1018         public function inNamespace( $ns ) {
1019                 return MWNamespace::equals( $this->getNamespace(), $ns );
1020         }
1021
1022         /**
1023          * Returns true if the title is inside one of the specified namespaces.
1024          *
1025          * @param ...$namespaces The namespaces to check for
1026          * @return bool
1027          * @since 1.19
1028          */
1029         public function inNamespaces( /* ... */ ) {
1030                 $namespaces = func_get_args();
1031                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1032                         $namespaces = $namespaces[0];
1033                 }
1034
1035                 foreach ( $namespaces as $ns ) {
1036                         if ( $this->inNamespace( $ns ) ) {
1037                                 return true;
1038                         }
1039                 }
1040
1041                 return false;
1042         }
1043
1044         /**
1045          * Returns true if the title has the same subject namespace as the
1046          * namespace specified.
1047          * For example this method will take NS_USER and return true if namespace
1048          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1049          * as their subject namespace.
1050          *
1051          * This is MUCH simpler than individually testing for equivalence
1052          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1053          * @since 1.19
1054          * @param $ns int
1055          * @return bool
1056          */
1057         public function hasSubjectNamespace( $ns ) {
1058                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1059         }
1060
1061         /**
1062          * Is this Title in a namespace which contains content?
1063          * In other words, is this a content page, for the purposes of calculating
1064          * statistics, etc?
1065          *
1066          * @return Boolean
1067          */
1068         public function isContentPage() {
1069                 return MWNamespace::isContent( $this->getNamespace() );
1070         }
1071
1072         /**
1073          * Would anybody with sufficient privileges be able to move this page?
1074          * Some pages just aren't movable.
1075          *
1076          * @return Bool TRUE or FALSE
1077          */
1078         public function isMovable() {
1079                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1080                         // Interwiki title or immovable namespace. Hooks don't get to override here
1081                         return false;
1082                 }
1083
1084                 $result = true;
1085                 wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
1086                 return $result;
1087         }
1088
1089         /**
1090          * Is this the mainpage?
1091          * @note Title::newFromText seems to be sufficiently optimized by the title
1092          * cache that we don't need to over-optimize by doing direct comparisons and
1093          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1094          * ends up reporting something differently than $title->isMainPage();
1095          *
1096          * @since 1.18
1097          * @return Bool
1098          */
1099         public function isMainPage() {
1100                 return $this->equals( Title::newMainPage() );
1101         }
1102
1103         /**
1104          * Is this a subpage?
1105          *
1106          * @return Bool
1107          */
1108         public function isSubpage() {
1109                 return MWNamespace::hasSubpages( $this->mNamespace )
1110                         ? strpos( $this->getText(), '/' ) !== false
1111                         : false;
1112         }
1113
1114         /**
1115          * Is this a conversion table for the LanguageConverter?
1116          *
1117          * @return Bool
1118          */
1119         public function isConversionTable() {
1120                 // @todo ConversionTable should become a separate content model.
1121
1122                 return $this->getNamespace() == NS_MEDIAWIKI &&
1123                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1124         }
1125
1126         /**
1127          * Does that page contain wikitext, or it is JS, CSS or whatever?
1128          *
1129          * @return Bool
1130          */
1131         public function isWikitextPage() {
1132                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1133         }
1134
1135         /**
1136          * Could this page contain custom CSS or JavaScript for the global UI.
1137          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1138          * or CONTENT_MODEL_JAVASCRIPT.
1139          *
1140          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage() for that!
1141          *
1142          * Note that this method should not return true for pages that contain and show "inactive" CSS or JS.
1143          *
1144          * @return Bool
1145          */
1146         public function isCssOrJsPage() {
1147                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1148                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1149                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1150
1151                 #NOTE: this hook is also called in ContentHandler::getDefaultModel. It's called here again to make sure
1152                 #      hook functions can force this method to return true even outside the mediawiki namespace.
1153
1154                 wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ) );
1155
1156                 return $isCssOrJsPage;
1157         }
1158
1159         /**
1160          * Is this a .css or .js subpage of a user page?
1161          * @return Bool
1162          */
1163         public function isCssJsSubpage() {
1164                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1165                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1166                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1167         }
1168
1169         /**
1170          * Trim down a .css or .js subpage title to get the corresponding skin name
1171          *
1172          * @return string containing skin name from .css or .js subpage title
1173          */
1174         public function getSkinFromCssJsSubpage() {
1175                 $subpage = explode( '/', $this->mTextform );
1176                 $subpage = $subpage[count( $subpage ) - 1];
1177                 $lastdot = strrpos( $subpage, '.' );
1178                 if ( $lastdot === false ) {
1179                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1180                 }
1181                 return substr( $subpage, 0, $lastdot );
1182         }
1183
1184         /**
1185          * Is this a .css subpage of a user page?
1186          *
1187          * @return Bool
1188          */
1189         public function isCssSubpage() {
1190                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1191                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1192         }
1193
1194         /**
1195          * Is this a .js subpage of a user page?
1196          *
1197          * @return Bool
1198          */
1199         public function isJsSubpage() {
1200                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1201                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1202         }
1203
1204         /**
1205          * Is this a talk page of some sort?
1206          *
1207          * @return Bool
1208          */
1209         public function isTalkPage() {
1210                 return MWNamespace::isTalk( $this->getNamespace() );
1211         }
1212
1213         /**
1214          * Get a Title object associated with the talk page of this article
1215          *
1216          * @return Title the object for the talk page
1217          */
1218         public function getTalkPage() {
1219                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1220         }
1221
1222         /**
1223          * Get a title object associated with the subject page of this
1224          * talk page
1225          *
1226          * @return Title the object for the subject page
1227          */
1228         public function getSubjectPage() {
1229                 // Is this the same title?
1230                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1231                 if ( $this->getNamespace() == $subjectNS ) {
1232                         return $this;
1233                 }
1234                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1235         }
1236
1237         /**
1238          * Get the default namespace index, for when there is no namespace
1239          *
1240          * @return Int Default namespace index
1241          */
1242         public function getDefaultNamespace() {
1243                 return $this->mDefaultNamespace;
1244         }
1245
1246         /**
1247          * Get the Title fragment (i.e.\ the bit after the #) in text form
1248          *
1249          * Use Title::hasFragment to check for a fragment
1250          *
1251          * @return String Title fragment
1252          */
1253         public function getFragment() {
1254                 return $this->mFragment;
1255         }
1256
1257         /**
1258          * Check if a Title fragment is set
1259          *
1260          * @return bool
1261          * @since 1.23
1262          */
1263         public function hasFragment() {
1264                 return $this->mFragment !== '';
1265         }
1266
1267         /**
1268          * Get the fragment in URL form, including the "#" character if there is one
1269          * @return String Fragment in URL form
1270          */
1271         public function getFragmentForURL() {
1272                 if ( !$this->hasFragment() ) {
1273                         return '';
1274                 } else {
1275                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1276                 }
1277         }
1278
1279         /**
1280          * Set the fragment for this title. Removes the first character from the
1281          * specified fragment before setting, so it assumes you're passing it with
1282          * an initial "#".
1283          *
1284          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1285          * Still in active use privately.
1286          *
1287          * @param string $fragment text
1288          */
1289         public function setFragment( $fragment ) {
1290                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1291         }
1292
1293         /**
1294          * Prefix some arbitrary text with the namespace or interwiki prefix
1295          * of this object
1296          *
1297          * @param string $name the text
1298          * @return String the prefixed text
1299          * @private
1300          */
1301         private function prefix( $name ) {
1302                 $p = '';
1303                 if ( $this->isExternal() ) {
1304                         $p = $this->mInterwiki . ':';
1305                 }
1306
1307                 if ( 0 != $this->mNamespace ) {
1308                         $p .= $this->getNsText() . ':';
1309                 }
1310                 return $p . $name;
1311         }
1312
1313         /**
1314          * Get the prefixed database key form
1315          *
1316          * @return String the prefixed title, with underscores and
1317          *  any interwiki and namespace prefixes
1318          */
1319         public function getPrefixedDBkey() {
1320                 $s = $this->prefix( $this->mDbkeyform );
1321                 $s = str_replace( ' ', '_', $s );
1322                 return $s;
1323         }
1324
1325         /**
1326          * Get the prefixed title with spaces.
1327          * This is the form usually used for display
1328          *
1329          * @return String the prefixed title, with spaces
1330          */
1331         public function getPrefixedText() {
1332                 if ( $this->mPrefixedText === null ) {
1333                         $s = $this->prefix( $this->mTextform );
1334                         $s = str_replace( '_', ' ', $s );
1335                         $this->mPrefixedText = $s;
1336                 }
1337                 return $this->mPrefixedText;
1338         }
1339
1340         /**
1341          * Return a string representation of this title
1342          *
1343          * @return String representation of this title
1344          */
1345         public function __toString() {
1346                 return $this->getPrefixedText();
1347         }
1348
1349         /**
1350          * Get the prefixed title with spaces, plus any fragment
1351          * (part beginning with '#')
1352          *
1353          * @return String the prefixed title, with spaces and the fragment, including '#'
1354          */
1355         public function getFullText() {
1356                 $text = $this->getPrefixedText();
1357                 if ( $this->hasFragment() ) {
1358                         $text .= '#' . $this->getFragment();
1359                 }
1360                 return $text;
1361         }
1362
1363         /**
1364          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1365          *
1366          * @par Example:
1367          * @code
1368          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1369          * # returns: 'Foo'
1370          * @endcode
1371          *
1372          * @return String Root name
1373          * @since 1.20
1374          */
1375         public function getRootText() {
1376                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1377                         return $this->getText();
1378                 }
1379
1380                 return strtok( $this->getText(), '/' );
1381         }
1382
1383         /**
1384          * Get the root page name title, i.e. the leftmost part before any slashes
1385          *
1386          * @par Example:
1387          * @code
1388          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1389          * # returns: Title{User:Foo}
1390          * @endcode
1391          *
1392          * @return Title Root title
1393          * @since 1.20
1394          */
1395         public function getRootTitle() {
1396                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1397         }
1398
1399         /**
1400          * Get the base page name without a namespace, i.e. the part before the subpage name
1401          *
1402          * @par Example:
1403          * @code
1404          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1405          * # returns: 'Foo/Bar'
1406          * @endcode
1407          *
1408          * @return String Base name
1409          */
1410         public function getBaseText() {
1411                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1412                         return $this->getText();
1413                 }
1414
1415                 $parts = explode( '/', $this->getText() );
1416                 # Don't discard the real title if there's no subpage involved
1417                 if ( count( $parts ) > 1 ) {
1418                         unset( $parts[count( $parts ) - 1] );
1419                 }
1420                 return implode( '/', $parts );
1421         }
1422
1423         /**
1424          * Get the base page name title, i.e. the part before the subpage name
1425          *
1426          * @par Example:
1427          * @code
1428          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1429          * # returns: Title{User:Foo/Bar}
1430          * @endcode
1431          *
1432          * @return Title Base title
1433          * @since 1.20
1434          */
1435         public function getBaseTitle() {
1436                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1437         }
1438
1439         /**
1440          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1441          *
1442          * @par Example:
1443          * @code
1444          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1445          * # returns: "Baz"
1446          * @endcode
1447          *
1448          * @return String Subpage name
1449          */
1450         public function getSubpageText() {
1451                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1452                         return $this->mTextform;
1453                 }
1454                 $parts = explode( '/', $this->mTextform );
1455                 return $parts[count( $parts ) - 1];
1456         }
1457
1458         /**
1459          * Get the title for a subpage of the current page
1460          *
1461          * @par Example:
1462          * @code
1463          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1464          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1465          * @endcode
1466          *
1467          * @param string $text The subpage name to add to the title
1468          * @return Title Subpage title
1469          * @since 1.20
1470          */
1471         public function getSubpage( $text ) {
1472                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1473         }
1474
1475         /**
1476          * Get the HTML-escaped displayable text form.
1477          * Used for the title field in <a> tags.
1478          *
1479          * @return String the text, including any prefixes
1480          * @deprecated since 1.19
1481          */
1482         public function getEscapedText() {
1483                 wfDeprecated( __METHOD__, '1.19' );
1484                 return htmlspecialchars( $this->getPrefixedText() );
1485         }
1486
1487         /**
1488          * Get a URL-encoded form of the subpage text
1489          *
1490          * @return String URL-encoded subpage name
1491          */
1492         public function getSubpageUrlForm() {
1493                 $text = $this->getSubpageText();
1494                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1495                 return $text;
1496         }
1497
1498         /**
1499          * Get a URL-encoded title (not an actual URL) including interwiki
1500          *
1501          * @return String the URL-encoded form
1502          */
1503         public function getPrefixedURL() {
1504                 $s = $this->prefix( $this->mDbkeyform );
1505                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1506                 return $s;
1507         }
1508
1509         /**
1510          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1511          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1512          * second argument named variant. This was deprecated in favor
1513          * of passing an array of option with a "variant" key
1514          * Once $query2 is removed for good, this helper can be dropped
1515          * and the wfArrayToCgi moved to getLocalURL();
1516          *
1517          * @since 1.19 (r105919)
1518          * @param $query
1519          * @param $query2 bool
1520          * @return String
1521          */
1522         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1523                 if ( $query2 !== false ) {
1524                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1525                                 "method called with a second parameter is deprecated. Add your " .
1526                                 "parameter to an array passed as the first parameter.", "1.19" );
1527                 }
1528                 if ( is_array( $query ) ) {
1529                         $query = wfArrayToCgi( $query );
1530                 }
1531                 if ( $query2 ) {
1532                         if ( is_string( $query2 ) ) {
1533                                 // $query2 is a string, we will consider this to be
1534                                 // a deprecated $variant argument and add it to the query
1535                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1536                         } else {
1537                                 $query2 = wfArrayToCgi( $query2 );
1538                         }
1539                         // If we have $query content add a & to it first
1540                         if ( $query ) {
1541                                 $query .= '&';
1542                         }
1543                         // Now append the queries together
1544                         $query .= $query2;
1545                 }
1546                 return $query;
1547         }
1548
1549         /**
1550          * Get a real URL referring to this title, with interwiki link and
1551          * fragment
1552          *
1553          * @see self::getLocalURL for the arguments.
1554          * @see wfExpandUrl
1555          * @param $query
1556          * @param $query2 bool
1557          * @param $proto Protocol type to use in URL
1558          * @return String the URL
1559          */
1560         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1561                 $query = self::fixUrlQueryArgs( $query, $query2 );
1562
1563                 # Hand off all the decisions on urls to getLocalURL
1564                 $url = $this->getLocalURL( $query );
1565
1566                 # Expand the url to make it a full url. Note that getLocalURL has the
1567                 # potential to output full urls for a variety of reasons, so we use
1568                 # wfExpandUrl instead of simply prepending $wgServer
1569                 $url = wfExpandUrl( $url, $proto );
1570
1571                 # Finally, add the fragment.
1572                 $url .= $this->getFragmentForURL();
1573
1574                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1575                 return $url;
1576         }
1577
1578         /**
1579          * Get a URL with no fragment or server name (relative URL) from a Title object.
1580          * If this page is generated with action=render, however,
1581          * $wgServer is prepended to make an absolute URL.
1582          *
1583          * @see self::getFullURL to always get an absolute URL.
1584          * @see self::newFromText to produce a Title object.
1585          *
1586          * @param string|array $query an optional query string,
1587          *   not used for interwiki links. Can be specified as an associative array as well,
1588          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1589          *   Some query patterns will trigger various shorturl path replacements.
1590          * @param $query2 Mixed: An optional secondary query array. This one MUST
1591          *   be an array. If a string is passed it will be interpreted as a deprecated
1592          *   variant argument and urlencoded into a variant= argument.
1593          *   This second query argument will be added to the $query
1594          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1595          *   pair in the first parameter array instead.
1596          *
1597          * @return String of the URL.
1598          */
1599         public function getLocalURL( $query = '', $query2 = false ) {
1600                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1601
1602                 $query = self::fixUrlQueryArgs( $query, $query2 );
1603
1604                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1605                 if ( $interwiki ) {
1606                         $namespace = $this->getNsText();
1607                         if ( $namespace != '' ) {
1608                                 # Can this actually happen? Interwikis shouldn't be parsed.
1609                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1610                                 $namespace .= ':';
1611                         }
1612                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1613                         $url = wfAppendQuery( $url, $query );
1614                 } else {
1615                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1616                         if ( $query == '' ) {
1617                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1618                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1619                         } else {
1620                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1621                                 $url = false;
1622                                 $matches = array();
1623
1624                                 if ( !empty( $wgActionPaths )
1625                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1626                                 ) {
1627                                         $action = urldecode( $matches[2] );
1628                                         if ( isset( $wgActionPaths[$action] ) ) {
1629                                                 $query = $matches[1];
1630                                                 if ( isset( $matches[4] ) ) {
1631                                                         $query .= $matches[4];
1632                                                 }
1633                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1634                                                 if ( $query != '' ) {
1635                                                         $url = wfAppendQuery( $url, $query );
1636                                                 }
1637                                         }
1638                                 }
1639
1640                                 if ( $url === false
1641                                         && $wgVariantArticlePath
1642                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1643                                         && $this->getPageLanguage()->hasVariants()
1644                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1645                                 ) {
1646                                         $variant = urldecode( $matches[1] );
1647                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1648                                                 // Only do the variant replacement if the given variant is a valid
1649                                                 // variant for the page's language.
1650                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1651                                                 $url = str_replace( '$1', $dbkey, $url );
1652                                         }
1653                                 }
1654
1655                                 if ( $url === false ) {
1656                                         if ( $query == '-' ) {
1657                                                 $query = '';
1658                                         }
1659                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1660                                 }
1661                         }
1662
1663                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1664
1665                         // @todo FIXME: This causes breakage in various places when we
1666                         // actually expected a local URL and end up with dupe prefixes.
1667                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1668                                 $url = $wgServer . $url;
1669                         }
1670                 }
1671                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1672                 return $url;
1673         }
1674
1675         /**
1676          * Get a URL that's the simplest URL that will be valid to link, locally,
1677          * to the current Title.  It includes the fragment, but does not include
1678          * the server unless action=render is used (or the link is external).  If
1679          * there's a fragment but the prefixed text is empty, we just return a link
1680          * to the fragment.
1681          *
1682          * The result obviously should not be URL-escaped, but does need to be
1683          * HTML-escaped if it's being output in HTML.
1684          *
1685          * @param $query
1686          * @param $query2 bool
1687          * @param $proto Protocol to use; setting this will cause a full URL to be used
1688          * @see self::getLocalURL for the arguments.
1689          * @return String the URL
1690          */
1691         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1692                 wfProfileIn( __METHOD__ );
1693                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1694                         $ret = $this->getFullURL( $query, $query2, $proto );
1695                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1696                         $ret = $this->getFragmentForURL();
1697                 } else {
1698                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1699                 }
1700                 wfProfileOut( __METHOD__ );
1701                 return $ret;
1702         }
1703
1704         /**
1705          * Get an HTML-escaped version of the URL form, suitable for
1706          * using in a link, without a server name or fragment
1707          *
1708          * @see self::getLocalURL for the arguments.
1709          * @param $query string
1710          * @param $query2 bool|string
1711          * @return String the URL
1712          * @deprecated since 1.19
1713          */
1714         public function escapeLocalURL( $query = '', $query2 = false ) {
1715                 wfDeprecated( __METHOD__, '1.19' );
1716                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1717         }
1718
1719         /**
1720          * Get an HTML-escaped version of the URL form, suitable for
1721          * using in a link, including the server name and fragment
1722          *
1723          * @see self::getLocalURL for the arguments.
1724          * @return String the URL
1725          * @deprecated since 1.19
1726          */
1727         public function escapeFullURL( $query = '', $query2 = false ) {
1728                 wfDeprecated( __METHOD__, '1.19' );
1729                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1730         }
1731
1732         /**
1733          * Get the URL form for an internal link.
1734          * - Used in various Squid-related code, in case we have a different
1735          * internal hostname for the server from the exposed one.
1736          *
1737          * This uses $wgInternalServer to qualify the path, or $wgServer
1738          * if $wgInternalServer is not set. If the server variable used is
1739          * protocol-relative, the URL will be expanded to http://
1740          *
1741          * @see self::getLocalURL for the arguments.
1742          * @return String the URL
1743          */
1744         public function getInternalURL( $query = '', $query2 = false ) {
1745                 global $wgInternalServer, $wgServer;
1746                 $query = self::fixUrlQueryArgs( $query, $query2 );
1747                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1748                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1749                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1750                 return $url;
1751         }
1752
1753         /**
1754          * Get the URL for a canonical link, for use in things like IRC and
1755          * e-mail notifications. Uses $wgCanonicalServer and the
1756          * GetCanonicalURL hook.
1757          *
1758          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1759          *
1760          * @see self::getLocalURL for the arguments.
1761          * @return string The URL
1762          * @since 1.18
1763          */
1764         public function getCanonicalURL( $query = '', $query2 = false ) {
1765                 $query = self::fixUrlQueryArgs( $query, $query2 );
1766                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1767                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1768                 return $url;
1769         }
1770
1771         /**
1772          * HTML-escaped version of getCanonicalURL()
1773          *
1774          * @see self::getLocalURL for the arguments.
1775          * @since 1.18
1776          * @return string
1777          * @deprecated since 1.19
1778          */
1779         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1780                 wfDeprecated( __METHOD__, '1.19' );
1781                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1782         }
1783
1784         /**
1785          * Get the edit URL for this Title
1786          *
1787          * @return String the URL, or a null string if this is an
1788          *  interwiki link
1789          */
1790         public function getEditURL() {
1791                 if ( $this->isExternal() ) {
1792                         return '';
1793                 }
1794                 $s = $this->getLocalURL( 'action=edit' );
1795
1796                 return $s;
1797         }
1798
1799         /**
1800          * Is $wgUser watching this page?
1801          *
1802          * @deprecated since 1.20; use User::isWatched() instead.
1803          * @return Bool
1804          */
1805         public function userIsWatching() {
1806                 global $wgUser;
1807
1808                 if ( is_null( $this->mWatched ) ) {
1809                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1810                                 $this->mWatched = false;
1811                         } else {
1812                                 $this->mWatched = $wgUser->isWatched( $this );
1813                         }
1814                 }
1815                 return $this->mWatched;
1816         }
1817
1818         /**
1819          * Can $wgUser read this page?
1820          *
1821          * @deprecated since 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1822          * @return Bool
1823          */
1824         public function userCanRead() {
1825                 wfDeprecated( __METHOD__, '1.19' );
1826                 return $this->userCan( 'read' );
1827         }
1828
1829         /**
1830          * Can $user perform $action on this page?
1831          * This skips potentially expensive cascading permission checks
1832          * as well as avoids expensive error formatting
1833          *
1834          * Suitable for use for nonessential UI controls in common cases, but
1835          * _not_ for functional access control.
1836          *
1837          * May provide false positives, but should never provide a false negative.
1838          *
1839          * @param string $action action that permission needs to be checked for
1840          * @param $user User to check (since 1.19); $wgUser will be used if not
1841          *              provided.
1842          * @return Bool
1843          */
1844         public function quickUserCan( $action, $user = null ) {
1845                 return $this->userCan( $action, $user, false );
1846         }
1847
1848         /**
1849          * Can $user perform $action on this page?
1850          *
1851          * @param string $action action that permission needs to be checked for
1852          * @param $user User to check (since 1.19); $wgUser will be used if not
1853          *   provided.
1854          * @param bool $doExpensiveQueries Set this to false to avoid doing
1855          *   unnecessary queries.
1856          * @return Bool
1857          */
1858         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1859                 if ( !$user instanceof User ) {
1860                         global $wgUser;
1861                         $user = $wgUser;
1862                 }
1863                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries, true ) );
1864         }
1865
1866         /**
1867          * Can $user perform $action on this page?
1868          *
1869          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1870          *
1871          * @param string $action action that permission needs to be checked for
1872          * @param $user User to check
1873          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1874          *   queries by skipping checks for cascading protections and user blocks.
1875          * @param array $ignoreErrors of Strings Set this to a list of message keys
1876          *   whose corresponding errors may be ignored.
1877          * @return Array of arguments to wfMessage to explain permissions problems.
1878          */
1879         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
1880                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1881
1882                 // Remove the errors being ignored.
1883                 foreach ( $errors as $index => $error ) {
1884                         $error_key = is_array( $error ) ? $error[0] : $error;
1885
1886                         if ( in_array( $error_key, $ignoreErrors ) ) {
1887                                 unset( $errors[$index] );
1888                         }
1889                 }
1890
1891                 return $errors;
1892         }
1893
1894         /**
1895          * Permissions checks that fail most often, and which are easiest to test.
1896          *
1897          * @param string $action the action to check
1898          * @param $user User user to check
1899          * @param array $errors list of current errors
1900          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1901          * @param $short Boolean short circuit on first error
1902          *
1903          * @return Array list of errors
1904          */
1905         private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1906                 if ( !wfRunHooks( 'TitleQuickPermissions', array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) ) ) {
1907                         return $errors;
1908                 }
1909
1910                 if ( $action == 'create' ) {
1911                         if (
1912                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1913                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1914                         ) {
1915                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1916                         }
1917                 } elseif ( $action == 'move' ) {
1918                         if ( !$user->isAllowed( 'move-rootuserpages' )
1919                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1920                                 // Show user page-specific message only if the user can move other pages
1921                                 $errors[] = array( 'cant-move-user-page' );
1922                         }
1923
1924                         // Check if user is allowed to move files if it's a file
1925                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1926                                 $errors[] = array( 'movenotallowedfile' );
1927                         }
1928
1929                         if ( !$user->isAllowed( 'move' ) ) {
1930                                 // User can't move anything
1931                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1932                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1933                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1934                                         // custom message if logged-in users without any special rights can move
1935                                         $errors[] = array( 'movenologintext' );
1936                                 } else {
1937                                         $errors[] = array( 'movenotallowed' );
1938                                 }
1939                         }
1940                 } elseif ( $action == 'move-target' ) {
1941                         if ( !$user->isAllowed( 'move' ) ) {
1942                                 // User can't move anything
1943                                 $errors[] = array( 'movenotallowed' );
1944                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1945                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1946                                 // Show user page-specific message only if the user can move other pages
1947                                 $errors[] = array( 'cant-move-to-user-page' );
1948                         }
1949                 } elseif ( !$user->isAllowed( $action ) ) {
1950                         $errors[] = $this->missingPermissionError( $action, $short );
1951                 }
1952
1953                 return $errors;
1954         }
1955
1956         /**
1957          * Add the resulting error code to the errors array
1958          *
1959          * @param array $errors list of current errors
1960          * @param $result Mixed result of errors
1961          *
1962          * @return Array list of errors
1963          */
1964         private function resultToError( $errors, $result ) {
1965                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1966                         // A single array representing an error
1967                         $errors[] = $result;
1968                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
1969                         // A nested array representing multiple errors
1970                         $errors = array_merge( $errors, $result );
1971                 } elseif ( $result !== '' && is_string( $result ) ) {
1972                         // A string representing a message-id
1973                         $errors[] = array( $result );
1974                 } elseif ( $result === false ) {
1975                         // a generic "We don't want them to do that"
1976                         $errors[] = array( 'badaccess-group0' );
1977                 }
1978                 return $errors;
1979         }
1980
1981         /**
1982          * Check various permission hooks
1983          *
1984          * @param string $action the action to check
1985          * @param $user User user to check
1986          * @param array $errors list of current errors
1987          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1988          * @param $short Boolean short circuit on first error
1989          *
1990          * @return Array list of errors
1991          */
1992         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
1993                 // Use getUserPermissionsErrors instead
1994                 $result = '';
1995                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
1996                         return $result ? array() : array( array( 'badaccess-group0' ) );
1997                 }
1998                 // Check getUserPermissionsErrors hook
1999                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2000                         $errors = $this->resultToError( $errors, $result );
2001                 }
2002                 // Check getUserPermissionsErrorsExpensive hook
2003                 if (
2004                         $doExpensiveQueries
2005                         && !( $short && count( $errors ) > 0 )
2006                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2007                 ) {
2008                         $errors = $this->resultToError( $errors, $result );
2009                 }
2010
2011                 return $errors;
2012         }
2013
2014         /**
2015          * Check permissions on special pages & namespaces
2016          *
2017          * @param string $action the action to check
2018          * @param $user User user to check
2019          * @param array $errors list of current errors
2020          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2021          * @param $short Boolean short circuit on first error
2022          *
2023          * @return Array list of errors
2024          */
2025         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2026                 # Only 'createaccount' can be performed on special pages,
2027                 # which don't actually exist in the DB.
2028                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2029                         $errors[] = array( 'ns-specialprotected' );
2030                 }
2031
2032                 # Check $wgNamespaceProtection for restricted namespaces
2033                 if ( $this->isNamespaceProtected( $user ) ) {
2034                         $ns = $this->mNamespace == NS_MAIN ?
2035                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2036                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2037                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
2038                 }
2039
2040                 return $errors;
2041         }
2042
2043         /**
2044          * Check CSS/JS sub-page permissions
2045          *
2046          * @param string $action the action to check
2047          * @param $user User user to check
2048          * @param array $errors list of current errors
2049          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2050          * @param $short Boolean short circuit on first error
2051          *
2052          * @return Array list of errors
2053          */
2054         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2055                 # Protect css/js subpages of user pages
2056                 # XXX: this might be better using restrictions
2057                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2058                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2059                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2060                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2061                                         $errors[] = array( 'mycustomcssprotected' );
2062                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2063                                         $errors[] = array( 'mycustomjsprotected' );
2064                                 }
2065                         } else {
2066                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2067                                         $errors[] = array( 'customcssprotected' );
2068                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2069                                         $errors[] = array( 'customjsprotected' );
2070                                 }
2071                         }
2072                 }
2073
2074                 return $errors;
2075         }
2076
2077         /**
2078          * Check against page_restrictions table requirements on this
2079          * page. The user must possess all required rights for this
2080          * action.
2081          *
2082          * @param string $action the action to check
2083          * @param $user User user to check
2084          * @param array $errors list of current errors
2085          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2086          * @param $short Boolean short circuit on first error
2087          *
2088          * @return Array list of errors
2089          */
2090         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2091                 foreach ( $this->getRestrictions( $action ) as $right ) {
2092                         // Backwards compatibility, rewrite sysop -> editprotected
2093                         if ( $right == 'sysop' ) {
2094                                 $right = 'editprotected';
2095                         }
2096                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2097                         if ( $right == 'autoconfirmed' ) {
2098                                 $right = 'editsemiprotected';
2099                         }
2100                         if ( $right == '' ) {
2101                                 continue;
2102                         }
2103                         if ( !$user->isAllowed( $right ) ) {
2104                                 $errors[] = array( 'protectedpagetext', $right );
2105                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2106                                 $errors[] = array( 'protectedpagetext', 'protect' );
2107                         }
2108                 }
2109
2110                 return $errors;
2111         }
2112
2113         /**
2114          * Check restrictions on cascading pages.
2115          *
2116          * @param string $action the action to check
2117          * @param $user User to check
2118          * @param array $errors list of current errors
2119          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2120          * @param $short Boolean short circuit on first error
2121          *
2122          * @return Array list of errors
2123          */
2124         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2125                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2126                         # We /could/ use the protection level on the source page, but it's
2127                         # fairly ugly as we have to establish a precedence hierarchy for pages
2128                         # included by multiple cascade-protected pages. So just restrict
2129                         # it to people with 'protect' permission, as they could remove the
2130                         # protection anyway.
2131                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2132                         # Cascading protection depends on more than this page...
2133                         # Several cascading protected pages may include this page...
2134                         # Check each cascading level
2135                         # This is only for protection restrictions, not for all actions
2136                         if ( isset( $restrictions[$action] ) ) {
2137                                 foreach ( $restrictions[$action] as $right ) {
2138                                         // Backwards compatibility, rewrite sysop -> editprotected
2139                                         if ( $right == 'sysop' ) {
2140                                                 $right = 'editprotected';
2141                                         }
2142                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2143                                         if ( $right == 'autoconfirmed' ) {
2144                                                 $right = 'editsemiprotected';
2145                                         }
2146                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2147                                                 $pages = '';
2148                                                 foreach ( $cascadingSources as $page ) {
2149                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2150                                                 }
2151                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2152                                         }
2153                                 }
2154                         }
2155                 }
2156
2157                 return $errors;
2158         }
2159
2160         /**
2161          * Check action permissions not already checked in checkQuickPermissions
2162          *
2163          * @param string $action the action to check
2164          * @param $user User to check
2165          * @param array $errors list of current errors
2166          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2167          * @param $short Boolean short circuit on first error
2168          *
2169          * @return Array list of errors
2170          */
2171         private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2172                 global $wgDeleteRevisionsLimit, $wgLang;
2173
2174                 if ( $action == 'protect' ) {
2175                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $doExpensiveQueries, true ) ) ) {
2176                                 // If they can't edit, they shouldn't protect.
2177                                 $errors[] = array( 'protect-cantedit' );
2178                         }
2179                 } elseif ( $action == 'create' ) {
2180                         $title_protection = $this->getTitleProtection();
2181                         if ( $title_protection ) {
2182                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2183                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2184                                 }
2185                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2186                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2187                                 }
2188                                 if ( $title_protection['pt_create_perm'] == ''
2189                                         || !$user->isAllowed( $title_protection['pt_create_perm'] )
2190                                 ) {
2191                                         $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
2192                                 }
2193                         }
2194                 } elseif ( $action == 'move' ) {
2195                         // Check for immobile pages
2196                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2197                                 // Specific message for this case
2198                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2199                         } elseif ( !$this->isMovable() ) {
2200                                 // Less specific message for rarer cases
2201                                 $errors[] = array( 'immobile-source-page' );
2202                         }
2203                 } elseif ( $action == 'move-target' ) {
2204                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2205                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2206                         } elseif ( !$this->isMovable() ) {
2207                                 $errors[] = array( 'immobile-target-page' );
2208                         }
2209                 } elseif ( $action == 'delete' ) {
2210                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2211                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2212                         ) {
2213                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2214                         }
2215                 }
2216                 return $errors;
2217         }
2218
2219         /**
2220          * Check that the user isn't blocked from editing.
2221          *
2222          * @param string $action the action to check
2223          * @param $user User to check
2224          * @param array $errors list of current errors
2225          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2226          * @param $short Boolean short circuit on first error
2227          *
2228          * @return Array list of errors
2229          */
2230         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2231                 // Account creation blocks handled at userlogin.
2232                 // Unblocking handled in SpecialUnblock
2233                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2234                         return $errors;
2235                 }
2236
2237                 global $wgEmailConfirmToEdit;
2238
2239                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2240                         $errors[] = array( 'confirmedittext' );
2241                 }
2242
2243                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2244                         // Don't block the user from editing their own talk page unless they've been
2245                         // explicitly blocked from that too.
2246                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2247                         // @todo FIXME: Pass the relevant context into this function.
2248                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2249                 }
2250
2251                 return $errors;
2252         }
2253
2254         /**
2255          * Check that the user is allowed to read this page.
2256          *
2257          * @param string $action the action to check
2258          * @param $user User to check
2259          * @param array $errors list of current errors
2260          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2261          * @param $short Boolean short circuit on first error
2262          *
2263          * @return Array list of errors
2264          */
2265         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2266                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2267
2268                 $whitelisted = false;
2269                 if ( User::isEveryoneAllowed( 'read' ) ) {
2270                         # Shortcut for public wikis, allows skipping quite a bit of code
2271                         $whitelisted = true;
2272                 } elseif ( $user->isAllowed( 'read' ) ) {
2273                         # If the user is allowed to read pages, he is allowed to read all pages
2274                         $whitelisted = true;
2275                 } elseif ( $this->isSpecial( 'Userlogin' )
2276                         || $this->isSpecial( 'ChangePassword' )
2277                         || $this->isSpecial( 'PasswordReset' )
2278                 ) {
2279                         # Always grant access to the login page.
2280                         # Even anons need to be able to log in.
2281                         $whitelisted = true;
2282                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2283                         # Time to check the whitelist
2284                         # Only do these checks is there's something to check against
2285                         $name = $this->getPrefixedText();
2286                         $dbName = $this->getPrefixedDBkey();
2287
2288                         // Check for explicit whitelisting with and without underscores
2289                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2290                                 $whitelisted = true;
2291                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2292                                 # Old settings might have the title prefixed with
2293                                 # a colon for main-namespace pages
2294                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2295                                         $whitelisted = true;
2296                                 }
2297                         } elseif ( $this->isSpecialPage() ) {
2298                                 # If it's a special page, ditch the subpage bit and check again
2299                                 $name = $this->getDBkey();
2300                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2301                                 if ( $name ) {
2302                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2303                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2304                                                 $whitelisted = true;
2305                                         }
2306                                 }
2307                         }
2308                 }
2309
2310                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2311                         $name = $this->getPrefixedText();
2312                         // Check for regex whitelisting
2313                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2314                                 if ( preg_match( $listItem, $name ) ) {
2315                                         $whitelisted = true;
2316                                         break;
2317                                 }
2318                         }
2319                 }
2320
2321                 if ( !$whitelisted ) {
2322                         # If the title is not whitelisted, give extensions a chance to do so...
2323                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2324                         if ( !$whitelisted ) {
2325                                 $errors[] = $this->missingPermissionError( $action, $short );
2326                         }
2327                 }
2328
2329                 return $errors;
2330         }
2331
2332         /**
2333          * Get a description array when the user doesn't have the right to perform
2334          * $action (i.e. when User::isAllowed() returns false)
2335          *
2336          * @param string $action the action to check
2337          * @param $short Boolean short circuit on first error
2338          * @return Array list of errors
2339          */
2340         private function missingPermissionError( $action, $short ) {
2341                 // We avoid expensive display logic for quickUserCan's and such
2342                 if ( $short ) {
2343                         return array( 'badaccess-group0' );
2344                 }
2345
2346                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2347                         User::getGroupsWithPermission( $action ) );
2348
2349                 if ( count( $groups ) ) {
2350                         global $wgLang;
2351                         return array(
2352                                 'badaccess-groups',
2353                                 $wgLang->commaList( $groups ),
2354                                 count( $groups )
2355                         );
2356                 } else {
2357                         return array( 'badaccess-group0' );
2358                 }
2359         }
2360
2361         /**
2362          * Can $user perform $action on this page? This is an internal function,
2363          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2364          * checks on wfReadOnly() and blocks)
2365          *
2366          * @param string $action action that permission needs to be checked for
2367          * @param $user User to check
2368          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2369          * @param bool $short Set this to true to stop after the first permission error.
2370          * @return Array of arrays of the arguments to wfMessage to explain permissions problems.
2371          */
2372         protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
2373                 wfProfileIn( __METHOD__ );
2374
2375                 # Read has special handling
2376                 if ( $action == 'read' ) {
2377                         $checks = array(
2378                                 'checkPermissionHooks',
2379                                 'checkReadPermissions',
2380                         );
2381                 } else {
2382                         $checks = array(
2383                                 'checkQuickPermissions',
2384                                 'checkPermissionHooks',
2385                                 'checkSpecialsAndNSPermissions',
2386                                 'checkCSSandJSPermissions',
2387                                 'checkPageRestrictions',
2388                                 'checkCascadingSourcesRestrictions',
2389                                 'checkActionPermissions',
2390                                 'checkUserBlock'
2391                         );
2392                 }
2393
2394                 $errors = array();
2395                 while ( count( $checks ) > 0 &&
2396                                 !( $short && count( $errors ) > 0 ) ) {
2397                         $method = array_shift( $checks );
2398                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2399                 }
2400
2401                 wfProfileOut( __METHOD__ );
2402                 return $errors;
2403         }
2404
2405         /**
2406          * Get a filtered list of all restriction types supported by this wiki.
2407          * @param bool $exists True to get all restriction types that apply to
2408          * titles that do exist, False for all restriction types that apply to
2409          * titles that do not exist
2410          * @return array
2411          */
2412         public static function getFilteredRestrictionTypes( $exists = true ) {
2413                 global $wgRestrictionTypes;
2414                 $types = $wgRestrictionTypes;
2415                 if ( $exists ) {
2416                         # Remove the create restriction for existing titles
2417                         $types = array_diff( $types, array( 'create' ) );
2418                 } else {
2419                         # Only the create and upload restrictions apply to non-existing titles
2420                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2421                 }
2422                 return $types;
2423         }
2424
2425         /**
2426          * Returns restriction types for the current Title
2427          *
2428          * @return array applicable restriction types
2429          */
2430         public function getRestrictionTypes() {
2431                 if ( $this->isSpecialPage() ) {
2432                         return array();
2433                 }
2434
2435                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2436
2437                 if ( $this->getNamespace() != NS_FILE ) {
2438                         # Remove the upload restriction for non-file titles
2439                         $types = array_diff( $types, array( 'upload' ) );
2440                 }
2441
2442                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2443
2444                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2445                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2446
2447                 return $types;
2448         }
2449
2450         /**
2451          * Is this title subject to title protection?
2452          * Title protection is the one applied against creation of such title.
2453          *
2454          * @return Mixed An associative array representing any existent title
2455          *   protection, or false if there's none.
2456          */
2457         private function getTitleProtection() {
2458                 // Can't protect pages in special namespaces
2459                 if ( $this->getNamespace() < 0 ) {
2460                         return false;
2461                 }
2462
2463                 // Can't protect pages that exist.
2464                 if ( $this->exists() ) {
2465                         return false;
2466                 }
2467
2468                 if ( !isset( $this->mTitleProtection ) ) {
2469                         $dbr = wfGetDB( DB_SLAVE );
2470                         $res = $dbr->select(
2471                                 'protected_titles',
2472                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2473                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2474                                 __METHOD__
2475                         );
2476
2477                         // fetchRow returns false if there are no rows.
2478                         $this->mTitleProtection = $dbr->fetchRow( $res );
2479                 }
2480                 return $this->mTitleProtection;
2481         }
2482
2483         /**
2484          * Update the title protection status
2485          *
2486          * @deprecated since 1.19; use WikiPage::doUpdateRestrictions() instead.
2487          * @param $create_perm String Permission required for creation
2488          * @param string $reason Reason for protection
2489          * @param string $expiry Expiry timestamp
2490          * @return boolean true
2491          */
2492         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2493                 wfDeprecated( __METHOD__, '1.19' );
2494
2495                 global $wgUser;
2496
2497                 $limit = array( 'create' => $create_perm );
2498                 $expiry = array( 'create' => $expiry );
2499
2500                 $page = WikiPage::factory( $this );
2501                 $cascade = false;
2502                 $status = $page->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $wgUser );
2503
2504                 return $status->isOK();
2505         }
2506
2507         /**
2508          * Remove any title protection due to page existing
2509          */
2510         public function deleteTitleProtection() {
2511                 $dbw = wfGetDB( DB_MASTER );
2512
2513                 $dbw->delete(
2514                         'protected_titles',
2515                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2516                         __METHOD__
2517                 );
2518                 $this->mTitleProtection = false;
2519         }
2520
2521         /**
2522          * Is this page "semi-protected" - the *only* protection levels are listed
2523          * in $wgSemiprotectedRestrictionLevels?
2524          *
2525          * @param string $action Action to check (default: edit)
2526          * @return Bool
2527          */
2528         public function isSemiProtected( $action = 'edit' ) {
2529                 global $wgSemiprotectedRestrictionLevels;
2530
2531                 $restrictions = $this->getRestrictions( $action );
2532                 $semi = $wgSemiprotectedRestrictionLevels;
2533                 if ( !$restrictions || !$semi ) {
2534                         // Not protected, or all protection is full protection
2535                         return false;
2536                 }
2537
2538                 // Remap autoconfirmed to editsemiprotected for BC
2539                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2540                         $semi[$key] = 'editsemiprotected';
2541                 }
2542                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2543                         $restrictions[$key] = 'editsemiprotected';
2544                 }
2545
2546                 return !array_diff( $restrictions, $semi );
2547         }
2548
2549         /**
2550          * Does the title correspond to a protected article?
2551          *
2552          * @param string $action the action the page is protected from,
2553          * by default checks all actions.
2554          * @return Bool
2555          */
2556         public function isProtected( $action = '' ) {
2557                 global $wgRestrictionLevels;
2558
2559                 $restrictionTypes = $this->getRestrictionTypes();
2560
2561                 # Special pages have inherent protection
2562                 if ( $this->isSpecialPage() ) {
2563                         return true;
2564                 }
2565
2566                 # Check regular protection levels
2567                 foreach ( $restrictionTypes as $type ) {
2568                         if ( $action == $type || $action == '' ) {
2569                                 $r = $this->getRestrictions( $type );
2570                                 foreach ( $wgRestrictionLevels as $level ) {
2571                                         if ( in_array( $level, $r ) && $level != '' ) {
2572                                                 return true;
2573                                         }
2574                                 }
2575                         }
2576                 }
2577
2578                 return false;
2579         }
2580
2581         /**
2582          * Determines if $user is unable to edit this page because it has been protected
2583          * by $wgNamespaceProtection.
2584          *
2585          * @param $user User object to check permissions
2586          * @return Bool
2587          */
2588         public function isNamespaceProtected( User $user ) {
2589                 global $wgNamespaceProtection;
2590
2591                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2592                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2593                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2594                                         return true;
2595                                 }
2596                         }
2597                 }
2598                 return false;
2599         }
2600
2601         /**
2602          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2603          *
2604          * @return Bool If the page is subject to cascading restrictions.
2605          */
2606         public function isCascadeProtected() {
2607                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2608                 return ( $sources > 0 );
2609         }
2610
2611         /**
2612          * Determines whether cascading protection sources have already been loaded from
2613          * the database.
2614          *
2615          * @param bool $getPages True to check if the pages are loaded, or false to check
2616          * if the status is loaded.
2617          * @return bool Whether or not the specified information has been loaded
2618          * @since 1.23
2619          */
2620         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2621                 return $getPages ? isset( $this->mCascadeSources ) : isset( $this->mHasCascadingRestrictions );
2622         }
2623
2624         /**
2625          * Cascading protection: Get the source of any cascading restrictions on this page.
2626          *
2627          * @param bool $getPages Whether or not to retrieve the actual pages
2628          *        that the restrictions have come from.
2629          * @return Mixed Array of Title objects of the pages from which cascading restrictions
2630          *     have come, false for none, or true if such restrictions exist, but $getPages
2631          *     was not set.  The restriction array is an array of each type, each of which
2632          *     contains a array of unique groups.
2633          */
2634         public function getCascadeProtectionSources( $getPages = true ) {
2635                 global $wgContLang;
2636                 $pagerestrictions = array();
2637
2638                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2639                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2640                 } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2641                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2642                 }
2643
2644                 wfProfileIn( __METHOD__ );
2645
2646                 $dbr = wfGetDB( DB_SLAVE );
2647
2648                 if ( $this->getNamespace() == NS_FILE ) {
2649                         $tables = array( 'imagelinks', 'page_restrictions' );
2650                         $where_clauses = array(
2651                                 'il_to' => $this->getDBkey(),
2652                                 'il_from=pr_page',
2653                                 'pr_cascade' => 1
2654                         );
2655                 } else {
2656                         $tables = array( 'templatelinks', 'page_restrictions' );
2657                         $where_clauses = array(
2658                                 'tl_namespace' => $this->getNamespace(),
2659                                 'tl_title' => $this->getDBkey(),
2660                                 'tl_from=pr_page',
2661                                 'pr_cascade' => 1
2662                         );
2663                 }
2664
2665                 if ( $getPages ) {
2666                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2667                                 'pr_expiry', 'pr_type', 'pr_level' );
2668                         $where_clauses[] = 'page_id=pr_page';
2669                         $tables[] = 'page';
2670                 } else {
2671                         $cols = array( 'pr_expiry' );
2672                 }
2673
2674                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2675
2676                 $sources = $getPages ? array() : false;
2677                 $now = wfTimestampNow();
2678                 $purgeExpired = false;
2679
2680                 foreach ( $res as $row ) {
2681                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2682                         if ( $expiry > $now ) {
2683                                 if ( $getPages ) {
2684                                         $page_id = $row->pr_page;
2685                                         $page_ns = $row->page_namespace;
2686                                         $page_title = $row->page_title;
2687                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2688                                         # Add groups needed for each restriction type if its not already there
2689                                         # Make sure this restriction type still exists
2690
2691                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2692                                                 $pagerestrictions[$row->pr_type] = array();
2693                                         }
2694
2695                                         if (
2696                                                 isset( $pagerestrictions[$row->pr_type] )
2697                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2698                                         ) {
2699                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2700                                         }
2701                                 } else {
2702                                         $sources = true;
2703                                 }
2704                         } else {
2705                                 // Trigger lazy purge of expired restrictions from the db
2706                                 $purgeExpired = true;
2707                         }
2708                 }
2709                 if ( $purgeExpired ) {
2710                         Title::purgeExpiredRestrictions();
2711                 }
2712
2713                 if ( $getPages ) {
2714                         $this->mCascadeSources = $sources;
2715                         $this->mCascadingRestrictions = $pagerestrictions;
2716                 } else {
2717                         $this->mHasCascadingRestrictions = $sources;
2718                 }
2719
2720                 wfProfileOut( __METHOD__ );
2721                 return array( $sources, $pagerestrictions );
2722         }
2723
2724         /**
2725          * Accessor for mRestrictionsLoaded
2726          *
2727          * @return bool Whether or not the page's restrictions have already been
2728          * loaded from the database
2729          * @since 1.23
2730          */
2731         public function areRestrictionsLoaded() {
2732                 return $this->mRestrictionsLoaded;
2733         }
2734
2735         /**
2736          * Accessor/initialisation for mRestrictions
2737          *
2738          * @param string $action action that permission needs to be checked for
2739          * @return Array of Strings the array of groups allowed to edit this article
2740          */
2741         public function getRestrictions( $action ) {
2742                 if ( !$this->mRestrictionsLoaded ) {
2743                         $this->loadRestrictions();
2744                 }
2745                 return isset( $this->mRestrictions[$action] )
2746                                 ? $this->mRestrictions[$action]
2747                                 : array();
2748         }
2749
2750         /**
2751          * Accessor/initialisation for mRestrictions
2752          *
2753          * @return Array of Arrays of Strings the first level indexed by
2754          * action, the second level containing the names of the groups
2755          * allowed to perform each action
2756          * @since 1.23
2757          */
2758         public function getAllRestrictions() {
2759                 if ( !$this->mRestrictionsLoaded ) {
2760                         $this->loadRestrictions();
2761                 }
2762                 return $this->mRestrictions;
2763         }
2764
2765         /**
2766          * Get the expiry time for the restriction against a given action
2767          *
2768          * @param $action
2769          * @return String|Bool 14-char timestamp, or 'infinity' if the page is protected forever
2770          *     or not protected at all, or false if the action is not recognised.
2771          */
2772         public function getRestrictionExpiry( $action ) {
2773                 if ( !$this->mRestrictionsLoaded ) {
2774                         $this->loadRestrictions();
2775                 }
2776                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2777         }
2778
2779         /**
2780          * Returns cascading restrictions for the current article
2781          *
2782          * @return Boolean
2783          */
2784         function areRestrictionsCascading() {
2785                 if ( !$this->mRestrictionsLoaded ) {
2786                         $this->loadRestrictions();
2787                 }
2788
2789                 return $this->mCascadeRestriction;
2790         }
2791
2792         /**
2793          * Loads a string into mRestrictions array
2794          *
2795          * @param $res Resource restrictions as an SQL result.
2796          * @param string $oldFashionedRestrictions comma-separated list of page
2797          *        restrictions from page table (pre 1.10)
2798          */
2799         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2800                 $rows = array();
2801
2802                 foreach ( $res as $row ) {
2803                         $rows[] = $row;
2804                 }
2805
2806                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2807         }
2808
2809         /**
2810          * Compiles list of active page restrictions from both page table (pre 1.10)
2811          * and page_restrictions table for this existing page.
2812          * Public for usage by LiquidThreads.
2813          *
2814          * @param array $rows of db result objects
2815          * @param string $oldFashionedRestrictions comma-separated list of page
2816          *        restrictions from page table (pre 1.10)
2817          */
2818         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2819                 global $wgContLang;
2820                 $dbr = wfGetDB( DB_SLAVE );
2821
2822                 $restrictionTypes = $this->getRestrictionTypes();
2823
2824                 foreach ( $restrictionTypes as $type ) {
2825                         $this->mRestrictions[$type] = array();
2826                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2827                 }
2828
2829                 $this->mCascadeRestriction = false;
2830
2831                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2832
2833                 if ( $oldFashionedRestrictions === null ) {
2834                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2835                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2836                 }
2837
2838                 if ( $oldFashionedRestrictions != '' ) {
2839
2840                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2841                                 $temp = explode( '=', trim( $restrict ) );
2842                                 if ( count( $temp ) == 1 ) {
2843                                         // old old format should be treated as edit/move restriction
2844                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2845                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2846                                 } else {
2847                                         $restriction = trim( $temp[1] );
2848                                         if ( $restriction != '' ) { //some old entries are empty
2849                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2850                                         }
2851                                 }
2852                         }
2853
2854                         $this->mOldRestrictions = true;
2855
2856                 }
2857
2858                 if ( count( $rows ) ) {
2859                         # Current system - load second to make them override.
2860                         $now = wfTimestampNow();
2861                         $purgeExpired = false;
2862
2863                         # Cycle through all the restrictions.
2864                         foreach ( $rows as $row ) {
2865
2866                                 // Don't take care of restrictions types that aren't allowed
2867                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2868                                         continue;
2869                                 }
2870
2871                                 // This code should be refactored, now that it's being used more generally,
2872                                 // But I don't really see any harm in leaving it in Block for now -werdna
2873                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2874
2875                                 // Only apply the restrictions if they haven't expired!
2876                                 if ( !$expiry || $expiry > $now ) {
2877                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2878                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2879
2880                                         $this->mCascadeRestriction |= $row->pr_cascade;
2881                                 } else {
2882                                         // Trigger a lazy purge of expired restrictions
2883                                         $purgeExpired = true;
2884                                 }
2885                         }
2886
2887                         if ( $purgeExpired ) {
2888                                 Title::purgeExpiredRestrictions();
2889                         }
2890                 }
2891
2892                 $this->mRestrictionsLoaded = true;
2893         }
2894
2895         /**
2896          * Load restrictions from the page_restrictions table
2897          *
2898          * @param string $oldFashionedRestrictions comma-separated list of page
2899          *        restrictions from page table (pre 1.10)
2900          */
2901         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2902                 global $wgContLang;
2903                 if ( !$this->mRestrictionsLoaded ) {
2904                         if ( $this->exists() ) {
2905                                 $dbr = wfGetDB( DB_SLAVE );
2906
2907                                 $res = $dbr->select(
2908                                         'page_restrictions',
2909                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2910                                         array( 'pr_page' => $this->getArticleID() ),
2911                                         __METHOD__
2912                                 );
2913
2914                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2915                         } else {
2916                                 $title_protection = $this->getTitleProtection();
2917
2918                                 if ( $title_protection ) {
2919                                         $now = wfTimestampNow();
2920                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2921
2922                                         if ( !$expiry || $expiry > $now ) {
2923                                                 // Apply the restrictions
2924                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2925                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2926                                         } else { // Get rid of the old restrictions
2927                                                 Title::purgeExpiredRestrictions();
2928                                                 $this->mTitleProtection = false;
2929                                         }
2930                                 } else {
2931                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2932                                 }
2933                                 $this->mRestrictionsLoaded = true;
2934                         }
2935                 }
2936         }
2937
2938         /**
2939          * Flush the protection cache in this object and force reload from the database.
2940          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2941          */
2942         public function flushRestrictions() {
2943                 $this->mRestrictionsLoaded = false;
2944                 $this->mTitleProtection = null;
2945         }
2946
2947         /**
2948          * Purge expired restrictions from the page_restrictions table
2949          */
2950         static function purgeExpiredRestrictions() {
2951                 if ( wfReadOnly() ) {
2952                         return;
2953                 }
2954
2955                 $method = __METHOD__;
2956                 $dbw = wfGetDB( DB_MASTER );
2957                 $dbw->onTransactionIdle( function() use ( $dbw, $method ) {
2958                         $dbw->delete(
2959                                 'page_restrictions',
2960                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2961                                 $method
2962                         );
2963                         $dbw->delete(
2964                                 'protected_titles',
2965                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2966                                 $method
2967                         );
2968                 } );
2969         }
2970
2971         /**
2972          * Does this have subpages?  (Warning, usually requires an extra DB query.)
2973          *
2974          * @return Bool
2975          */
2976         public function hasSubpages() {
2977                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
2978                         # Duh
2979                         return false;
2980                 }
2981
2982                 # We dynamically add a member variable for the purpose of this method
2983                 # alone to cache the result.  There's no point in having it hanging
2984                 # around uninitialized in every Title object; therefore we only add it
2985                 # if needed and don't declare it statically.
2986                 if ( !isset( $this->mHasSubpages ) ) {
2987                         $this->mHasSubpages = false;
2988                         $subpages = $this->getSubpages( 1 );
2989                         if ( $subpages instanceof TitleArray ) {
2990                                 $this->mHasSubpages = (bool)$subpages->count();
2991                         }
2992                 }
2993
2994                 return $this->mHasSubpages;
2995         }
2996
2997         /**
2998          * Get all subpages of this page.
2999          *
3000          * @param int $limit maximum number of subpages to fetch; -1 for no limit
3001          * @return mixed TitleArray, or empty array if this page's namespace
3002          *  doesn't allow subpages
3003          */
3004         public function getSubpages( $limit = -1 ) {
3005                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3006                         return array();
3007                 }
3008
3009                 $dbr = wfGetDB( DB_SLAVE );
3010                 $conds['page_namespace'] = $this->getNamespace();
3011                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3012                 $options = array();
3013                 if ( $limit > -1 ) {
3014                         $options['LIMIT'] = $limit;
3015                 }
3016                 $this->mSubpages = TitleArray::newFromResult(
3017                         $dbr->select( 'page',
3018                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3019                                 $conds,
3020                                 __METHOD__,
3021                                 $options
3022                         )
3023                 );
3024                 return $this->mSubpages;
3025         }
3026
3027         /**
3028          * Is there a version of this page in the deletion archive?
3029          *
3030          * @return Int the number of archived revisions
3031          */
3032         public function isDeleted() {
3033                 if ( $this->getNamespace() < 0 ) {
3034                         $n = 0;
3035                 } else {
3036                         $dbr = wfGetDB( DB_SLAVE );
3037
3038                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3039                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3040                                 __METHOD__
3041                         );
3042                         if ( $this->getNamespace() == NS_FILE ) {
3043                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3044                                         array( 'fa_name' => $this->getDBkey() ),
3045                                         __METHOD__
3046                                 );
3047                         }
3048                 }
3049                 return (int)$n;
3050         }
3051
3052         /**
3053          * Is there a version of this page in the deletion archive?
3054          *
3055          * @return Boolean
3056          */
3057         public function isDeletedQuick() {
3058                 if ( $this->getNamespace() < 0 ) {
3059                         return false;
3060                 }
3061                 $dbr = wfGetDB( DB_SLAVE );
3062                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3063                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3064                         __METHOD__
3065                 );
3066                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3067                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3068                                 array( 'fa_name' => $this->getDBkey() ),
3069                                 __METHOD__
3070                         );
3071                 }
3072                 return $deleted;
3073         }
3074
3075         /**
3076          * Get the article ID for this Title from the link cache,
3077          * adding it if necessary
3078          *
3079          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select
3080          *  for update
3081          * @return Int the ID
3082          */
3083         public function getArticleID( $flags = 0 ) {
3084                 if ( $this->getNamespace() < 0 ) {
3085                         $this->mArticleID = 0;
3086                         return $this->mArticleID;
3087                 }
3088                 $linkCache = LinkCache::singleton();
3089                 if ( $flags & self::GAID_FOR_UPDATE ) {
3090                         $oldUpdate = $linkCache->forUpdate( true );
3091                         $linkCache->clearLink( $this );
3092                         $this->mArticleID = $linkCache->addLinkObj( $this );
3093                         $linkCache->forUpdate( $oldUpdate );
3094                 } else {
3095                         if ( -1 == $this->mArticleID ) {
3096                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3097                         }
3098                 }
3099                 return $this->mArticleID;
3100         }
3101
3102         /**
3103          * Is this an article that is a redirect page?
3104          * Uses link cache, adding it if necessary
3105          *
3106          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3107          * @return Bool
3108          */
3109         public function isRedirect( $flags = 0 ) {
3110                 if ( !is_null( $this->mRedirect ) ) {
3111                         return $this->mRedirect;
3112                 }
3113                 # Calling getArticleID() loads the field from cache as needed
3114                 if ( !$this->getArticleID( $flags ) ) {
3115                         $this->mRedirect = false;
3116                         return $this->mRedirect;
3117                 }
3118
3119                 $linkCache = LinkCache::singleton();
3120                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3121                 if ( $cached === null ) {
3122                         # Trust LinkCache's state over our own
3123                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3124                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3125                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3126                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3127                         # LinkCache to refresh its data from the master.
3128                         $this->mRedirect = false;
3129                         return $this->mRedirect;
3130                 }
3131
3132                 $this->mRedirect = (bool)$cached;
3133
3134                 return $this->mRedirect;
3135         }
3136
3137         /**
3138          * What is the length of this page?
3139          * Uses link cache, adding it if necessary
3140          *
3141          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3142          * @return Int
3143          */
3144         public function getLength( $flags = 0 ) {
3145                 if ( $this->mLength != -1 ) {
3146                         return $this->mLength;
3147                 }
3148                 # Calling getArticleID() loads the field from cache as needed
3149                 if ( !$this->getArticleID( $flags ) ) {
3150                         $this->mLength = 0;
3151                         return $this->mLength;
3152                 }
3153                 $linkCache = LinkCache::singleton();
3154                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3155                 if ( $cached === null ) {
3156                         # Trust LinkCache's state over our own, as for isRedirect()
3157                         $this->mLength = 0;
3158                         return $this->mLength;
3159                 }
3160
3161                 $this->mLength = intval( $cached );
3162
3163                 return $this->mLength;
3164         }
3165
3166         /**
3167          * What is the page_latest field for this page?
3168          *
3169          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3170          * @return Int or 0 if the page doesn't exist
3171          */
3172         public function getLatestRevID( $flags = 0 ) {
3173                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3174                         return intval( $this->mLatestID );
3175                 }
3176                 # Calling getArticleID() loads the field from cache as needed
3177                 if ( !$this->getArticleID( $flags ) ) {
3178                         $this->mLatestID = 0;
3179                         return $this->mLatestID;
3180                 }
3181                 $linkCache = LinkCache::singleton();
3182                 $linkCache->addLinkObj( $this );
3183                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3184                 if ( $cached === null ) {
3185                         # Trust LinkCache's state over our own, as for isRedirect()
3186                         $this->mLatestID = 0;
3187                         return $this->mLatestID;
3188                 }
3189
3190                 $this->mLatestID = intval( $cached );
3191
3192                 return $this->mLatestID;
3193         }
3194
3195         /**
3196          * This clears some fields in this object, and clears any associated
3197          * keys in the "bad links" section of the link cache.
3198          *
3199          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3200          * loading of the new page_id. It's also called from
3201          * WikiPage::doDeleteArticleReal()
3202          *
3203          * @param int $newid the new Article ID
3204          */
3205         public function resetArticleID( $newid ) {
3206                 $linkCache = LinkCache::singleton();
3207                 $linkCache->clearLink( $this );
3208
3209                 if ( $newid === false ) {
3210                         $this->mArticleID = -1;
3211                 } else {
3212                         $this->mArticleID = intval( $newid );
3213                 }
3214                 $this->mRestrictionsLoaded = false;
3215                 $this->mRestrictions = array();
3216                 $this->mRedirect = null;
3217                 $this->mLength = -1;
3218                 $this->mLatestID = false;
3219                 $this->mContentModel = false;
3220                 $this->mEstimateRevisions = null;
3221                 $this->mPageLanguage = false;
3222         }
3223
3224         /**
3225          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3226          *
3227          * @param string $text containing title to capitalize
3228          * @param int $ns namespace index, defaults to NS_MAIN
3229          * @return String containing capitalized title
3230          */
3231         public static function capitalize( $text, $ns = NS_MAIN ) {
3232                 global $wgContLang;
3233
3234                 if ( MWNamespace::isCapitalized( $ns ) ) {
3235                         return $wgContLang->ucfirst( $text );
3236                 } else {
3237                         return $text;
3238                 }
3239         }
3240
3241         /**
3242          * Secure and split - main initialisation function for this object
3243          *
3244          * Assumes that mDbkeyform has been set, and is urldecoded
3245          * and uses underscores, but not otherwise munged.  This function
3246          * removes illegal characters, splits off the interwiki and
3247          * namespace prefixes, sets the other forms, and canonicalizes
3248          * everything.
3249          *
3250          * @return Bool true on success
3251          */
3252         private function secureAndSplit() {
3253                 # Initialisation
3254                 $this->mInterwiki = '';
3255                 $this->mFragment = '';
3256                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3257
3258                 $dbkey = $this->mDbkeyform;
3259
3260                 try {
3261                         // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3262                         //        the parsing code with Title, while avoiding massive refactoring.
3263                         // @todo: get rid of secureAndSplit, refactor parsing code.
3264                         $parser = $this->getTitleParser();
3265                         $parts = $parser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3266                 } catch ( MalformedTitleException $ex ) {
3267                         return false;
3268                 }
3269
3270                 # Fill fields
3271                 $this->setFragment( '#' . $parts['fragment'] );
3272                 $this->mInterwiki = $parts['interwiki'];
3273                 $this->mNamespace = $parts['namespace'];
3274                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3275
3276                 $this->mDbkeyform = $parts['dbkey'];
3277                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3278                 $this->mTextform = str_replace( '_', ' ', $this->mDbkeyform );
3279
3280                 # We already know that some pages won't be in the database!
3281                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3282                         $this->mArticleID = 0;
3283                 }
3284
3285                 return true;
3286         }
3287
3288         /**
3289          * Get an array of Title objects linking to this Title
3290          * Also stores the IDs in the link cache.
3291          *
3292          * WARNING: do not use this function on arbitrary user-supplied titles!
3293          * On heavily-used templates it will max out the memory.
3294          *
3295          * @param array $options may be FOR UPDATE
3296          * @param string $table table name
3297          * @param string $prefix fields prefix
3298          * @return Array of Title objects linking here
3299          */
3300         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3301                 if ( count( $options ) > 0 ) {
3302                         $db = wfGetDB( DB_MASTER );
3303                 } else {
3304                         $db = wfGetDB( DB_SLAVE );
3305                 }
3306
3307                 $res = $db->select(
3308                         array( 'page', $table ),
3309                         self::getSelectFields(),
3310                         array(
3311                                 "{$prefix}_from=page_id",
3312                                 "{$prefix}_namespace" => $this->getNamespace(),
3313                                 "{$prefix}_title" => $this->getDBkey() ),
3314                         __METHOD__,
3315                         $options
3316                 );
3317
3318                 $retVal = array();
3319                 if ( $res->numRows() ) {
3320                         $linkCache = LinkCache::singleton();
3321                         foreach ( $res as $row ) {
3322                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3323                                 if ( $titleObj ) {
3324                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3325                                         $retVal[] = $titleObj;
3326                                 }
3327                         }
3328                 }
3329                 return $retVal;
3330         }
3331
3332         /**
3333          * Get an array of Title objects using this Title as a template
3334          * Also stores the IDs in the link cache.
3335          *
3336          * WARNING: do not use this function on arbitrary user-supplied titles!
3337          * On heavily-used templates it will max out the memory.
3338          *
3339          * @param array $options may be FOR UPDATE
3340          * @return Array of Title the Title objects linking here
3341          */
3342         public function getTemplateLinksTo( $options = array() ) {
3343                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3344         }
3345
3346         /**
3347          * Get an array of Title objects linked from this Title
3348          * Also stores the IDs in the link cache.
3349          *
3350          * WARNING: do not use this function on arbitrary user-supplied titles!
3351          * On heavily-used templates it will max out the memory.
3352          *
3353          * @param array $options may be FOR UPDATE
3354          * @param string $table table name
3355          * @param string $prefix fields prefix
3356          * @return Array of Title objects linking here
3357          */
3358         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3359                 global $wgContentHandlerUseDB;
3360
3361                 $id = $this->getArticleID();
3362
3363                 # If the page doesn't exist; there can't be any link from this page
3364                 if ( !$id ) {
3365                         return array();
3366                 }
3367
3368                 if ( count( $options ) > 0 ) {
3369                         $db = wfGetDB( DB_MASTER );
3370                 } else {
3371                         $db = wfGetDB( DB_SLAVE );
3372                 }
3373
3374                 $namespaceFiled = "{$prefix}_namespace";
3375                 $titleField = "{$prefix}_title";
3376
3377                 $fields = array( $namespaceFiled, $titleField, 'page_id', 'page_len', 'page_is_redirect', 'page_latest' );
3378                 if ( $wgContentHandlerUseDB ) {
3379                         $fields[] = 'page_content_model';
3380                 }
3381
3382                 $res = $db->select(
3383                         array( $table, 'page' ),
3384                         $fields,
3385                         array( "{$prefix}_from" => $id ),
3386                         __METHOD__,
3387                         $options,
3388                         array( 'page' => array( 'LEFT JOIN', array( "page_namespace=$namespaceFiled", "page_title=$titleField" ) ) )
3389                 );
3390
3391                 $retVal = array();
3392                 if ( $res->numRows() ) {
3393                         $linkCache = LinkCache::singleton();
3394                         foreach ( $res as $row ) {
3395                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3396                                 if ( $titleObj ) {
3397                                         if ( $row->page_id ) {
3398                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3399                                         } else {
3400                                                 $linkCache->addBadLinkObj( $titleObj );
3401                                         }
3402                                         $retVal[] = $titleObj;
3403                                 }
3404                         }
3405                 }
3406                 return $retVal;
3407         }
3408
3409         /**
3410          * Get an array of Title objects used on this Title as a template
3411          * Also stores the IDs in the link cache.
3412          *
3413          * WARNING: do not use this function on arbitrary user-supplied titles!
3414          * On heavily-used templates it will max out the memory.
3415          *
3416          * @param array $options may be FOR UPDATE
3417          * @return Array of Title the Title objects used here
3418          */
3419         public function getTemplateLinksFrom( $options = array() ) {
3420                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3421         }
3422
3423         /**
3424          * Get an array of Title objects referring to non-existent articles linked from this page
3425          *
3426          * @todo check if needed (used only in SpecialBrokenRedirects.php, and should use redirect table in this case)
3427          * @return Array of Title the Title objects
3428          */
3429         public function getBrokenLinksFrom() {
3430                 if ( $this->getArticleID() == 0 ) {
3431                         # All links from article ID 0 are false positives
3432                         return array();
3433                 }
3434
3435                 $dbr = wfGetDB( DB_SLAVE );
3436                 $res = $dbr->select(
3437                         array( 'page', 'pagelinks' ),
3438                         array( 'pl_namespace', 'pl_title' ),
3439                         array(
3440                                 'pl_from' => $this->getArticleID(),
3441                                 'page_namespace IS NULL'
3442                         ),
3443                         __METHOD__, array(),
3444                         array(
3445                                 'page' => array(
3446                                         'LEFT JOIN',
3447                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3448                                 )
3449                         )
3450                 );
3451
3452                 $retVal = array();
3453                 foreach ( $res as $row ) {
3454                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3455                 }
3456                 return $retVal;
3457         }
3458
3459         /**
3460          * Get a list of URLs to purge from the Squid cache when this
3461          * page changes
3462          *
3463          * @return Array of String the URLs
3464          */
3465         public function getSquidURLs() {
3466                 $urls = array(
3467                         $this->getInternalURL(),
3468                         $this->getInternalURL( 'action=history' )
3469                 );
3470
3471                 $pageLang = $this->getPageLanguage();
3472                 if ( $pageLang->hasVariants() ) {
3473                         $variants = $pageLang->getVariants();
3474                         foreach ( $variants as $vCode ) {
3475                                 $urls[] = $this->getInternalURL( '', $vCode );
3476                         }
3477                 }
3478
3479                 // If we are looking at a css/js user subpage, purge the action=raw.
3480                 if ( $this->isJsSubpage() ) {
3481                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3482                 } elseif ( $this->isCssSubpage() ) {
3483                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3484                 }
3485
3486                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3487                 return $urls;
3488         }
3489
3490         /**
3491          * Purge all applicable Squid URLs
3492          */
3493         public function purgeSquid() {
3494                 global $wgUseSquid;
3495                 if ( $wgUseSquid ) {
3496                         $urls = $this->getSquidURLs();
3497                         $u = new SquidUpdate( $urls );
3498                         $u->doUpdate();
3499                 }
3500         }
3501
3502         /**
3503          * Move this page without authentication
3504          *
3505          * @param $nt Title the new page Title
3506          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3507          */
3508         public function moveNoAuth( &$nt ) {
3509                 return $this->moveTo( $nt, false );
3510         }
3511
3512         /**
3513          * Check whether a given move operation would be valid.
3514          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3515          *
3516          * @param $nt Title the new title
3517          * @param bool $auth indicates whether $wgUser's permissions
3518          *  should be checked
3519          * @param string $reason is the log summary of the move, used for spam checking
3520          * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
3521          */
3522         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3523                 global $wgUser, $wgContentHandlerUseDB;
3524
3525                 $errors = array();
3526                 if ( !$nt ) {
3527                         // Normally we'd add this to $errors, but we'll get
3528                         // lots of syntax errors if $nt is not an object
3529                         return array( array( 'badtitletext' ) );
3530                 }
3531                 if ( $this->equals( $nt ) ) {
3532                         $errors[] = array( 'selfmove' );
3533                 }
3534                 if ( !$this->isMovable() ) {
3535                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3536                 }
3537                 if ( $nt->isExternal() ) {
3538                         $errors[] = array( 'immobile-target-namespace-iw' );
3539                 }
3540                 if ( !$nt->isMovable() ) {
3541                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3542                 }
3543
3544                 $oldid = $this->getArticleID();
3545                 $newid = $nt->getArticleID();
3546
3547                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3548                         $errors[] = array( 'articleexists' );
3549                 }
3550                 if (
3551                         ( $this->getDBkey() == '' ) ||
3552                         ( !$oldid ) ||
3553                         ( $nt->getDBkey() == '' )
3554                 ) {
3555                         $errors[] = array( 'badarticleerror' );
3556                 }
3557
3558                 // Content model checks
3559                 if ( !$wgContentHandlerUseDB &&
3560                                 $this->getContentModel() !== $nt->getContentModel() ) {
3561                         // can't move a page if that would change the page's content model
3562                         $errors[] = array(
3563                                 'bad-target-model',
3564                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3565                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3566                         );
3567                 }
3568
3569                 // Image-specific checks
3570                 if ( $this->getNamespace() == NS_FILE ) {
3571                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3572                 }
3573
3574                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3575                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3576                 }
3577
3578                 if ( $auth ) {
3579                         $errors = wfMergeErrorArrays( $errors,
3580                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3581                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3582                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3583                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3584                 }
3585
3586                 $match = EditPage::matchSummarySpamRegex( $reason );
3587                 if ( $match !== false ) {
3588                         // This is kind of lame, won't display nice
3589                         $errors[] = array( 'spamprotectiontext' );
3590                 }
3591
3592                 $err = null;
3593                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3594                         $errors[] = array( 'hookaborted', $err );
3595                 }
3596
3597                 # The move is allowed only if (1) the target doesn't exist, or
3598                 # (2) the target is a redirect to the source, and has no history
3599                 # (so we can undo bad moves right after they're done).
3600
3601                 if ( 0 != $newid ) { # Target exists; check for validity
3602                         if ( !$this->isValidMoveTarget( $nt ) ) {
3603                                 $errors[] = array( 'articleexists' );
3604                         }
3605                 } else {
3606                         $tp = $nt->getTitleProtection();
3607                         $right = $tp['pt_create_perm'];
3608                         if ( $right == 'sysop' ) {
3609                                 $right = 'editprotected'; // B/C
3610                         }
3611                         if ( $right == 'autoconfirmed' ) {
3612                                 $right = 'editsemiprotected'; // B/C
3613                         }
3614                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3615                                 $errors[] = array( 'cantmove-titleprotected' );
3616                         }
3617                 }
3618                 if ( empty( $errors ) ) {
3619                         return true;
3620                 }
3621                 return $errors;
3622         }
3623
3624         /**
3625          * Check if the requested move target is a valid file move target
3626          * @param Title $nt Target title
3627          * @return array List of errors
3628          */
3629         protected function validateFileMoveOperation( $nt ) {
3630                 global $wgUser;
3631
3632                 $errors = array();
3633
3634                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3635
3636                 $file = wfLocalFile( $this );
3637                 if ( $file->exists() ) {
3638                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3639                                 $errors[] = array( 'imageinvalidfilename' );
3640                         }
3641                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3642                                 $errors[] = array( 'imagetypemismatch' );
3643                         }
3644                 }
3645
3646                 if ( $nt->getNamespace() != NS_FILE ) {
3647                         $errors[] = array( 'imagenocrossnamespace' );
3648                         // From here we want to do checks on a file object, so if we can't
3649                         // create one, we must return.
3650                         return $errors;
3651                 }
3652
3653                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3654
3655                 $destFile = wfLocalFile( $nt );
3656                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3657                         $errors[] = array( 'file-exists-sharedrepo' );
3658                 }
3659
3660                 return $errors;
3661         }
3662
3663         /**
3664          * Move a title to a new location
3665          *
3666          * @param $nt Title the new title
3667          * @param bool $auth indicates whether $wgUser's permissions
3668          *  should be checked
3669          * @param string $reason the reason for the move
3670          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3671          *  Ignored if the user doesn't have the suppressredirect right.
3672          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3673          */
3674         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3675                 global $wgUser;
3676                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3677                 if ( is_array( $err ) ) {
3678                         // Auto-block user's IP if the account was "hard" blocked
3679                         $wgUser->spreadAnyEditBlock();
3680                         return $err;
3681                 }
3682                 // Check suppressredirect permission
3683                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3684                         $createRedirect = true;
3685                 }
3686
3687                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3688
3689                 // If it is a file, move it first.
3690                 // It is done before all other moving stuff is done because it's hard to revert.
3691                 $dbw = wfGetDB( DB_MASTER );
3692                 if ( $this->getNamespace() == NS_FILE ) {
3693                         $file = wfLocalFile( $this );
3694                         if ( $file->exists() ) {
3695                                 $status = $file->move( $nt );
3696                                 if ( !$status->isOk() ) {
3697                                         return $status->getErrorsArray();
3698                                 }
3699                         }
3700                         // Clear RepoGroup process cache
3701                         RepoGroup::singleton()->clearCache( $this );
3702                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3703                 }
3704
3705                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3706                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3707                 $protected = $this->isProtected();
3708
3709                 // Do the actual move
3710                 $this->moveToInternal( $nt, $reason, $createRedirect );
3711
3712                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3713                 // cl_timestamp, which may disturb time-based lists on some sites.
3714                 $prefixes = $dbw->select(
3715                         'categorylinks',
3716                         array( 'cl_sortkey_prefix', 'cl_to' ),
3717                         array( 'cl_from' => $pageid ),
3718                         __METHOD__
3719                 );
3720                 foreach ( $prefixes as $prefixRow ) {
3721                         $prefix = $prefixRow->cl_sortkey_prefix;
3722                         $catTo = $prefixRow->cl_to;
3723                         $dbw->update( 'categorylinks',
3724                                 array(
3725                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3726                                                 $nt->getCategorySortkey( $prefix ) ),
3727                                         'cl_timestamp=cl_timestamp' ),
3728                                 array(
3729                                         'cl_from' => $pageid,
3730                                         'cl_to' => $catTo ),
3731                                 __METHOD__
3732                         );
3733                 }
3734
3735                 $redirid = $this->getArticleID();
3736
3737                 if ( $protected ) {
3738                         # Protect the redirect title as the title used to be...
3739                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3740                                 array(
3741                                         'pr_page' => $redirid,
3742                                         'pr_type' => 'pr_type',
3743                                         'pr_level' => 'pr_level',
3744                                         'pr_cascade' => 'pr_cascade',
3745                                         'pr_user' => 'pr_user',
3746                                         'pr_expiry' => 'pr_expiry'
3747                                 ),
3748                                 array( 'pr_page' => $pageid ),
3749                                 __METHOD__,
3750                                 array( 'IGNORE' )
3751                         );
3752                         # Update the protection log
3753                         $log = new LogPage( 'protect' );
3754                         $comment = wfMessage(
3755                                 'prot_1movedto2',
3756                                 $this->getPrefixedText(),
3757                                 $nt->getPrefixedText()
3758                         )->inContentLanguage()->text();
3759                         if ( $reason ) {
3760                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3761                         }
3762                         // @todo FIXME: $params?
3763                         $logId = $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ), $wgUser );
3764
3765                         // reread inserted pr_ids for log relation
3766                         $insertedPrIds = $dbw->select(
3767                                 'page_restrictions',
3768                                 'pr_id',
3769                                 array( 'pr_page' => $redirid ),
3770                                 __METHOD__
3771                         );
3772                         $logRelationsValues = array();
3773                         foreach ( $insertedPrIds as $prid ) {
3774                                 $logRelationsValues[] = $prid->pr_id;
3775                         }
3776                         $log->addRelations( 'pr_id', $logRelationsValues, $logId );
3777                 }
3778
3779                 # Update watchlists
3780                 $oldnamespace = MWNamespace::getSubject( $this->getNamespace() );
3781                 $newnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3782                 $oldtitle = $this->getDBkey();
3783                 $newtitle = $nt->getDBkey();
3784
3785                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3786                         WatchedItem::duplicateEntries( $this, $nt );
3787                 }
3788
3789                 $dbw->commit( __METHOD__ );
3790
3791                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid, $reason ) );
3792                 return true;
3793         }
3794
3795         /**
3796          * Move page to a title which is either a redirect to the
3797          * source page or nonexistent
3798          *
3799          * @param $nt Title the page to move to, which should be a redirect or nonexistent
3800          * @param string $reason The reason for the move
3801          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3802          *   if the user has the suppressredirect right
3803          * @throws MWException
3804          */
3805         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3806                 global $wgUser, $wgContLang;
3807
3808                 if ( $nt->exists() ) {
3809                         $moveOverRedirect = true;
3810                         $logType = 'move_redir';
3811                 } else {
3812                         $moveOverRedirect = false;
3813                         $logType = 'move';
3814                 }
3815
3816                 if ( $createRedirect ) {
3817                         $contentHandler = ContentHandler::getForTitle( $this );
3818                         $redirectContent = $contentHandler->makeRedirectContent( $nt,
3819                                 wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3820
3821                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3822                 } else {
3823                         $redirectContent = null;
3824                 }
3825
3826                 $logEntry = new ManualLogEntry( 'move', $logType );
3827                 $logEntry->setPerformer( $wgUser );
3828                 $logEntry->setTarget( $this );
3829                 $logEntry->setComment( $reason );
3830                 $logEntry->setParameters( array(
3831                         '4::target' => $nt->getPrefixedText(),
3832                         '5::noredir' => $redirectContent ? '0': '1',
3833                 ) );
3834
3835                 $formatter = LogFormatter::newFromEntry( $logEntry );
3836                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3837                 $comment = $formatter->getPlainActionText();
3838                 if ( $reason ) {
3839                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3840                 }
3841                 # Truncate for whole multibyte characters.
3842                 $comment = $wgContLang->truncate( $comment, 255 );
3843
3844                 $oldid = $this->getArticleID();
3845
3846                 $dbw = wfGetDB( DB_MASTER );
3847
3848                 $newpage = WikiPage::factory( $nt );
3849
3850                 if ( $moveOverRedirect ) {
3851                         $newid = $nt->getArticleID();
3852                         $newcontent = $newpage->getContent();
3853
3854                         # Delete the old redirect. We don't save it to history since
3855                         # by definition if we've got here it's rather uninteresting.
3856                         # We have to remove it so that the next step doesn't trigger
3857                         # a conflict on the unique namespace+title index...
3858                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3859
3860                         $newpage->doDeleteUpdates( $newid, $newcontent );
3861                 }
3862
3863                 # Save a null revision in the page's history notifying of the move
3864                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
3865                 if ( !is_object( $nullRevision ) ) {
3866                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3867                 }
3868
3869                 $nullRevision->insertOn( $dbw );
3870
3871                 # Change the name of the target page:
3872                 $dbw->update( 'page',
3873                         /* SET */ array(
3874                                 'page_namespace' => $nt->getNamespace(),
3875                                 'page_title' => $nt->getDBkey(),
3876                         ),
3877                         /* WHERE */ array( 'page_id' => $oldid ),
3878                         __METHOD__
3879                 );
3880
3881                 // clean up the old title before reset article id - bug 45348
3882                 if ( !$redirectContent ) {
3883                         WikiPage::onArticleDelete( $this );
3884                 }
3885
3886                 $this->resetArticleID( 0 ); // 0 == non existing
3887                 $nt->resetArticleID( $oldid );
3888                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
3889
3890                 $newpage->updateRevisionOn( $dbw, $nullRevision );
3891
3892                 wfRunHooks( 'NewRevisionFromEditComplete',
3893                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
3894
3895                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
3896
3897                 if ( !$moveOverRedirect ) {
3898                         WikiPage::onArticleCreate( $nt );
3899                 }
3900
3901                 # Recreate the redirect, this time in the other direction.
3902                 if ( $redirectContent ) {
3903                         $redirectArticle = WikiPage::factory( $this );
3904                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
3905                         $newid = $redirectArticle->insertOn( $dbw );
3906                         if ( $newid ) { // sanity
3907                                 $this->resetArticleID( $newid );
3908                                 $redirectRevision = new Revision( array(
3909                                         'title' => $this, // for determining the default content model
3910                                         'page' => $newid,
3911                                         'comment' => $comment,
3912                                         'content' => $redirectContent ) );
3913                                 $redirectRevision->insertOn( $dbw );
3914                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
3915
3916                                 wfRunHooks( 'NewRevisionFromEditComplete',
3917                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
3918
3919                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
3920                         }
3921                 }
3922
3923                 # Log the move
3924                 $logid = $logEntry->insert();
3925                 $logEntry->publish( $logid );
3926         }
3927
3928         /**
3929          * Move this page's subpages to be subpages of $nt
3930          *
3931          * @param $nt Title Move target
3932          * @param bool $auth Whether $wgUser's permissions should be checked
3933          * @param string $reason The reason for the move
3934          * @param bool $createRedirect Whether to create redirects from the old subpages to
3935          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3936          * @return mixed array with old page titles as keys, and strings (new page titles) or
3937          *     arrays (errors) as values, or an error array with numeric indices if no pages
3938          *     were moved
3939          */
3940         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3941                 global $wgMaximumMovedPages;
3942                 // Check permissions
3943                 if ( !$this->userCan( 'move-subpages' ) ) {
3944                         return array( 'cant-move-subpages' );
3945                 }
3946                 // Do the source and target namespaces support subpages?
3947                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3948                         return array( 'namespace-nosubpages',
3949                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3950                 }
3951                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3952                         return array( 'namespace-nosubpages',
3953                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3954                 }
3955
3956                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3957                 $retval = array();
3958                 $count = 0;
3959                 foreach ( $subpages as $oldSubpage ) {
3960                         $count++;
3961                         if ( $count > $wgMaximumMovedPages ) {
3962                                 $retval[$oldSubpage->getPrefixedText()] =
3963                                                 array( 'movepage-max-pages',
3964                                                         $wgMaximumMovedPages );
3965                                 break;
3966                         }
3967
3968                         // We don't know whether this function was called before
3969                         // or after moving the root page, so check both
3970                         // $this and $nt
3971                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3972                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3973                         ) {
3974                                 // When moving a page to a subpage of itself,
3975                                 // don't move it twice
3976                                 continue;
3977                         }
3978                         $newPageName = preg_replace(
3979                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3980                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3981                                         $oldSubpage->getDBkey() );
3982                         if ( $oldSubpage->isTalkPage() ) {
3983                                 $newNs = $nt->getTalkPage()->getNamespace();
3984                         } else {
3985                                 $newNs = $nt->getSubjectPage()->getNamespace();
3986                         }
3987                         # Bug 14385: we need makeTitleSafe because the new page names may
3988                         # be longer than 255 characters.
3989                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3990
3991                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3992                         if ( $success === true ) {
3993                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3994                         } else {
3995                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3996                         }
3997                 }
3998                 return $retval;
3999         }
4000
4001         /**
4002          * Checks if this page is just a one-rev redirect.
4003          * Adds lock, so don't use just for light purposes.
4004          *
4005          * @return Bool
4006          */
4007         public function isSingleRevRedirect() {
4008                 global $wgContentHandlerUseDB;
4009
4010                 $dbw = wfGetDB( DB_MASTER );
4011
4012                 # Is it a redirect?
4013                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4014                 if ( $wgContentHandlerUseDB ) {
4015                         $fields[] = 'page_content_model';
4016                 }
4017
4018                 $row = $dbw->selectRow( 'page',
4019                         $fields,
4020                         $this->pageCond(),
4021                         __METHOD__,
4022                         array( 'FOR UPDATE' )
4023                 );
4024                 # Cache some fields we may want
4025                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4026                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4027                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4028                 $this->mContentModel = $row && isset( $row->page_content_model ) ? strval( $row->page_content_model ) : false;
4029                 if ( !$this->mRedirect ) {
4030                         return false;
4031                 }
4032                 # Does the article have a history?
4033                 $row = $dbw->selectField( array( 'page', 'revision' ),
4034                         'rev_id',
4035                         array( 'page_namespace' => $this->getNamespace(),
4036                                 'page_title' => $this->getDBkey(),
4037                                 'page_id=rev_page',
4038                                 'page_latest != rev_id'
4039                         ),
4040                         __METHOD__,
4041                         array( 'FOR UPDATE' )
4042                 );
4043                 # Return true if there was no history
4044                 return ( $row === false );
4045         }
4046
4047         /**
4048          * Checks if $this can be moved to a given Title
4049          * - Selects for update, so don't call it unless you mean business
4050          *
4051          * @param $nt Title the new title to check
4052          * @return Bool
4053          */
4054         public function isValidMoveTarget( $nt ) {
4055                 # Is it an existing file?
4056                 if ( $nt->getNamespace() == NS_FILE ) {
4057                         $file = wfLocalFile( $nt );
4058                         if ( $file->exists() ) {
4059                                 wfDebug( __METHOD__ . ": file exists\n" );
4060                                 return false;
4061                         }
4062                 }
4063                 # Is it a redirect with no history?
4064                 if ( !$nt->isSingleRevRedirect() ) {
4065                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4066                         return false;
4067                 }
4068                 # Get the article text
4069                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4070                 if ( !is_object( $rev ) ) {
4071                         return false;
4072                 }
4073                 $content = $rev->getContent();
4074                 # Does the redirect point to the source?
4075                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4076                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4077
4078                 if ( $redirTitle ) {
4079                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4080                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4081                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4082                                 return false;
4083                         } else {
4084                                 return true;
4085                         }
4086                 } else {
4087                         # Fail safe (not a redirect after all. strange.)
4088                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4089                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4090                         return false;
4091                 }
4092         }
4093
4094         /**
4095          * Get categories to which this Title belongs and return an array of
4096          * categories' names.
4097          *
4098          * @return Array of parents in the form:
4099          *        $parent => $currentarticle
4100          */
4101         public function getParentCategories() {
4102                 global $wgContLang;
4103
4104                 $data = array();
4105
4106                 $titleKey = $this->getArticleID();
4107
4108                 if ( $titleKey === 0 ) {
4109                         return $data;
4110                 }
4111
4112                 $dbr = wfGetDB( DB_SLAVE );
4113
4114                 $res = $dbr->select(
4115                         'categorylinks',
4116                         'cl_to',
4117                         array( 'cl_from' => $titleKey ),
4118                         __METHOD__
4119                 );
4120
4121                 if ( $res->numRows() > 0 ) {
4122                         foreach ( $res as $row ) {
4123                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4124                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4125                         }
4126                 }
4127                 return $data;
4128         }
4129
4130         /**
4131          * Get a tree of parent categories
4132          *
4133          * @param array $children with the children in the keys, to check for circular refs
4134          * @return Array Tree of parent categories
4135          */
4136         public function getParentCategoryTree( $children = array() ) {
4137                 $stack = array();
4138                 $parents = $this->getParentCategories();
4139
4140                 if ( $parents ) {
4141                         foreach ( $parents as $parent => $current ) {
4142                                 if ( array_key_exists( $parent, $children ) ) {
4143                                         # Circular reference
4144                                         $stack[$parent] = array();
4145                                 } else {
4146                                         $nt = Title::newFromText( $parent );
4147                                         if ( $nt ) {
4148                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4149                                         }
4150                                 }
4151                         }
4152                 }
4153
4154                 return $stack;
4155         }
4156
4157         /**
4158          * Get an associative array for selecting this title from
4159          * the "page" table
4160          *
4161          * @return Array suitable for the $where parameter of DB::select()
4162          */
4163         public function pageCond() {
4164                 if ( $this->mArticleID > 0 ) {
4165                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4166                         return array( 'page_id' => $this->mArticleID );
4167                 } else {
4168                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4169                 }
4170         }
4171
4172         /**
4173          * Get the revision ID of the previous revision
4174          *
4175          * @param int $revId Revision ID. Get the revision that was before this one.
4176          * @param int $flags Title::GAID_FOR_UPDATE
4177          * @return Int|Bool Old revision ID, or FALSE if none exists
4178          */
4179         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4180                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4181                 $revId = $db->selectField( 'revision', 'rev_id',
4182                         array(
4183                                 'rev_page' => $this->getArticleID( $flags ),
4184                                 'rev_id < ' . intval( $revId )
4185                         ),
4186                         __METHOD__,
4187                         array( 'ORDER BY' => 'rev_id DESC' )
4188                 );
4189
4190                 if ( $revId === false ) {
4191                         return false;
4192                 } else {
4193                         return intval( $revId );
4194                 }
4195         }
4196
4197         /**
4198          * Get the revision ID of the next revision
4199          *
4200          * @param int $revId Revision ID. Get the revision that was after this one.
4201          * @param int $flags Title::GAID_FOR_UPDATE
4202          * @return Int|Bool Next revision ID, or FALSE if none exists
4203          */
4204         public function getNextRevisionID( $revId, $flags = 0 ) {
4205                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4206                 $revId = $db->selectField( 'revision', 'rev_id',
4207                         array(
4208                                 'rev_page' => $this->getArticleID( $flags ),
4209                                 'rev_id > ' . intval( $revId )
4210                         ),
4211                         __METHOD__,
4212                         array( 'ORDER BY' => 'rev_id' )
4213                 );
4214
4215                 if ( $revId === false ) {
4216                         return false;
4217                 } else {
4218                         return intval( $revId );
4219                 }
4220         }
4221
4222         /**
4223          * Get the first revision of the page
4224          *
4225          * @param int $flags Title::GAID_FOR_UPDATE
4226          * @return Revision|Null if page doesn't exist
4227          */
4228         public function getFirstRevision( $flags = 0 ) {
4229                 $pageId = $this->getArticleID( $flags );
4230                 if ( $pageId ) {
4231                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4232                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4233                                 array( 'rev_page' => $pageId ),
4234                                 __METHOD__,
4235                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4236                         );
4237                         if ( $row ) {
4238                                 return new Revision( $row );
4239                         }
4240                 }
4241                 return null;
4242         }
4243
4244         /**
4245          * Get the oldest revision timestamp of this page
4246          *
4247          * @param int $flags Title::GAID_FOR_UPDATE
4248          * @return String: MW timestamp
4249          */
4250         public function getEarliestRevTime( $flags = 0 ) {
4251                 $rev = $this->getFirstRevision( $flags );
4252                 return $rev ? $rev->getTimestamp() : null;
4253         }
4254
4255         /**
4256          * Check if this is a new page
4257          *
4258          * @return bool
4259          */
4260         public function isNewPage() {
4261                 $dbr = wfGetDB( DB_SLAVE );
4262                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4263         }
4264
4265         /**
4266          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4267          *
4268          * @return bool
4269          */
4270         public function isBigDeletion() {
4271                 global $wgDeleteRevisionsLimit;
4272
4273                 if ( !$wgDeleteRevisionsLimit ) {
4274                         return false;
4275                 }
4276
4277                 $revCount = $this->estimateRevisionCount();
4278                 return $revCount > $wgDeleteRevisionsLimit;
4279         }
4280
4281         /**
4282          * Get the  approximate revision count of this page.
4283          *
4284          * @return int
4285          */
4286         public function estimateRevisionCount() {
4287                 if ( !$this->exists() ) {
4288                         return 0;
4289                 }
4290
4291                 if ( $this->mEstimateRevisions === null ) {
4292                         $dbr = wfGetDB( DB_SLAVE );
4293                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4294                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4295                 }
4296
4297                 return $this->mEstimateRevisions;
4298         }
4299
4300         /**
4301          * Get the number of revisions between the given revision.
4302          * Used for diffs and other things that really need it.
4303          *
4304          * @param int|Revision $old Old revision or rev ID (first before range)
4305          * @param int|Revision $new New revision or rev ID (first after range)
4306          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4307          * @return Int Number of revisions between these revisions.
4308          */
4309         public function countRevisionsBetween( $old, $new, $max = null ) {
4310                 if ( !( $old instanceof Revision ) ) {
4311                         $old = Revision::newFromTitle( $this, (int)$old );
4312                 }
4313                 if ( !( $new instanceof Revision ) ) {
4314                         $new = Revision::newFromTitle( $this, (int)$new );
4315                 }
4316                 if ( !$old || !$new ) {
4317                         return 0; // nothing to compare
4318                 }
4319                 $dbr = wfGetDB( DB_SLAVE );
4320                 $conds = array(
4321                         'rev_page' => $this->getArticleID(),
4322                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4323                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4324                 );
4325                 if ( $max !== null ) {
4326                         $res = $dbr->select( 'revision', '1',
4327                                 $conds,
4328                                 __METHOD__,
4329                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4330                         );
4331                         return $res->numRows();
4332                 } else {
4333                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4334                 }
4335         }
4336
4337         /**
4338          * Get the authors between the given revisions or revision IDs.
4339          * Used for diffs and other things that really need it.
4340          *
4341          * @since 1.23
4342          *
4343          * @param int|Revision $old Old revision or rev ID (first before range by default)
4344          * @param int|Revision $new New revision or rev ID (first after range by default)
4345          * @param int $limit Maximum number of authors
4346          * @param string|array $options (Optional): Single option, or an array of options:
4347          *     'include_old' Include $old in the range; $new is excluded.
4348          *     'include_new' Include $new in the range; $old is excluded.
4349          *     'include_both' Include both $old and $new in the range.
4350          *     Unknown option values are ignored.
4351          * @return array|null Names of revision authors in the range; null if not both revisions exist
4352          */
4353         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4354                 if ( !( $old instanceof Revision ) ) {
4355                         $old = Revision::newFromTitle( $this, (int)$old );
4356                 }
4357                 if ( !( $new instanceof Revision ) ) {
4358                         $new = Revision::newFromTitle( $this, (int)$new );
4359                 }
4360                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4361                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4362                 // in the sanity check below?
4363                 if ( !$old || !$new ) {
4364                         return null; // nothing to compare
4365                 }
4366                 $authors = array();
4367                 $old_cmp = '>';
4368                 $new_cmp = '<';
4369                 $options = (array)$options;
4370                 if ( in_array( 'include_old', $options ) ) {
4371                         $old_cmp = '>=';
4372                 }
4373                 if ( in_array( 'include_new', $options ) ) {
4374                         $new_cmp = '<=';
4375                 }
4376                 if ( in_array( 'include_both', $options ) ) {
4377                         $old_cmp = '>=';
4378                         $new_cmp = '<=';
4379                 }
4380                 // No DB query needed if $old and $new are the same or successive revisions:
4381                 if ( $old->getId() === $new->getId() ) {
4382                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? array() : array( $old->getRawUserText() );
4383                 } elseif ( $old->getId() === $new->getParentId() ) {
4384                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4385                                 $authors[] = $old->getRawUserText();
4386                                 if ( $old->getRawUserText() != $new->getRawUserText() ) {
4387                                         $authors[] = $new->getRawUserText();
4388                                 }
4389                         } elseif ( $old_cmp === '>=' ) {
4390                                 $authors[] = $old->getRawUserText();
4391                         } elseif ( $new_cmp === '<=' ) {
4392                                 $authors[] = $new->getRawUserText();
4393                         }
4394                         return $authors;
4395                 }
4396                 $dbr = wfGetDB( DB_SLAVE );
4397                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4398                         array(
4399                                 'rev_page' => $this->getArticleID(),
4400                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4401                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4402                         ), __METHOD__,
4403                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4404                 );
4405                 foreach ( $res as $row ) {
4406                         $authors[] = $row->rev_user_text;
4407                 }
4408                 return $authors;
4409         }
4410
4411         /**
4412          * Get the number of authors between the given revisions or revision IDs.
4413          * Used for diffs and other things that really need it.
4414          *
4415          * @param int|Revision $old Old revision or rev ID (first before range by default)
4416          * @param int|Revision $new New revision or rev ID (first after range by default)
4417          * @param int $limit Maximum number of authors
4418          * @param string|array $options (Optional): Single option, or an array of options:
4419          *     'include_old' Include $old in the range; $new is excluded.
4420          *     'include_new' Include $new in the range; $old is excluded.
4421          *     'include_both' Include both $old and $new in the range.
4422          *     Unknown option values are ignored.
4423          * @return int Number of revision authors in the range; zero if not both revisions exist
4424          */
4425         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4426                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4427                 return $authors ? count( $authors ) : 0;
4428         }
4429
4430         /**
4431          * Compare with another title.
4432          *
4433          * @param $title Title
4434          * @return Bool
4435          */
4436         public function equals( Title $title ) {
4437                 // Note: === is necessary for proper matching of number-like titles.
4438                 return $this->getInterwiki() === $title->getInterwiki()
4439                         && $this->getNamespace() == $title->getNamespace()
4440                         && $this->getDBkey() === $title->getDBkey();
4441         }
4442
4443         /**
4444          * Check if this title is a subpage of another title
4445          *
4446          * @param $title Title
4447          * @return Bool
4448          */
4449         public function isSubpageOf( Title $title ) {
4450                 return $this->getInterwiki() === $title->getInterwiki()
4451                         && $this->getNamespace() == $title->getNamespace()
4452                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4453         }
4454
4455         /**
4456          * Check if page exists.  For historical reasons, this function simply
4457          * checks for the existence of the title in the page table, and will
4458          * thus return false for interwiki links, special pages and the like.
4459          * If you want to know if a title can be meaningfully viewed, you should
4460          * probably call the isKnown() method instead.
4461          *
4462          * @return Bool
4463          */
4464         public function exists() {
4465                 return $this->getArticleID() != 0;
4466         }
4467
4468         /**
4469          * Should links to this title be shown as potentially viewable (i.e. as
4470          * "bluelinks"), even if there's no record by this title in the page
4471          * table?
4472          *
4473          * This function is semi-deprecated for public use, as well as somewhat
4474          * misleadingly named.  You probably just want to call isKnown(), which
4475          * calls this function internally.
4476          *
4477          * (ISSUE: Most of these checks are cheap, but the file existence check
4478          * can potentially be quite expensive.  Including it here fixes a lot of
4479          * existing code, but we might want to add an optional parameter to skip
4480          * it and any other expensive checks.)
4481          *
4482          * @return Bool
4483          */
4484         public function isAlwaysKnown() {
4485                 $isKnown = null;
4486
4487                 /**
4488                  * Allows overriding default behavior for determining if a page exists.
4489                  * If $isKnown is kept as null, regular checks happen. If it's
4490                  * a boolean, this value is returned by the isKnown method.
4491                  *
4492                  * @since 1.20
4493                  *
4494                  * @param Title $title
4495                  * @param boolean|null $isKnown
4496                  */
4497                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4498
4499                 if ( !is_null( $isKnown ) ) {
4500                         return $isKnown;
4501                 }
4502
4503                 if ( $this->isExternal() ) {
4504                         return true;  // any interwiki link might be viewable, for all we know
4505                 }
4506
4507                 switch ( $this->mNamespace ) {
4508                         case NS_MEDIA:
4509                         case NS_FILE:
4510                                 // file exists, possibly in a foreign repo
4511                                 return (bool)wfFindFile( $this );
4512                         case NS_SPECIAL:
4513                                 // valid special page
4514                                 return SpecialPageFactory::exists( $this->getDBkey() );
4515                         case NS_MAIN:
4516                                 // selflink, possibly with fragment
4517                                 return $this->mDbkeyform == '';
4518                         case NS_MEDIAWIKI:
4519                                 // known system message
4520                                 return $this->hasSourceText() !== false;
4521                         default:
4522                                 return false;
4523                 }
4524         }
4525
4526         /**
4527          * Does this title refer to a page that can (or might) be meaningfully
4528          * viewed?  In particular, this function may be used to determine if
4529          * links to the title should be rendered as "bluelinks" (as opposed to
4530          * "redlinks" to non-existent pages).
4531          * Adding something else to this function will cause inconsistency
4532          * since LinkHolderArray calls isAlwaysKnown() and does its own
4533          * page existence check.
4534          *
4535          * @return Bool
4536          */
4537         public function isKnown() {
4538                 return $this->isAlwaysKnown() || $this->exists();
4539         }
4540
4541         /**
4542          * Does this page have source text?
4543          *
4544          * @return Boolean
4545          */
4546         public function hasSourceText() {
4547                 if ( $this->exists() ) {
4548                         return true;
4549                 }
4550
4551                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4552                         // If the page doesn't exist but is a known system message, default
4553                         // message content will be displayed, same for language subpages-
4554                         // Use always content language to avoid loading hundreds of languages
4555                         // to get the link color.
4556                         global $wgContLang;
4557                         list( $name, ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4558                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4559                         return $message->exists();
4560                 }
4561
4562                 return false;
4563         }
4564
4565         /**
4566          * Get the default message text or false if the message doesn't exist
4567          *
4568          * @return String or false
4569          */
4570         public function getDefaultMessageText() {
4571                 global $wgContLang;
4572
4573                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4574                         return false;
4575                 }
4576
4577                 list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4578                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4579
4580                 if ( $message->exists() ) {
4581                         return $message->plain();
4582                 } else {
4583                         return false;
4584                 }
4585         }
4586
4587         /**
4588          * Updates page_touched for this page; called from LinksUpdate.php
4589          *
4590          * @return Bool true if the update succeeded
4591          */
4592         public function invalidateCache() {
4593                 if ( wfReadOnly() ) {
4594                         return false;
4595                 }
4596
4597                 $method = __METHOD__;
4598                 $dbw = wfGetDB( DB_MASTER );
4599                 $conds = $this->pageCond();
4600                 $dbw->onTransactionIdle( function() use ( $dbw, $conds, $method ) {
4601                         $dbw->update(
4602                                 'page',
4603                                 array( 'page_touched' => $dbw->timestamp() ),
4604                                 $conds,
4605                                 $method
4606                         );
4607                 } );
4608
4609                 return true;
4610         }
4611
4612         /**
4613          * Update page_touched timestamps and send squid purge messages for
4614          * pages linking to this title. May be sent to the job queue depending
4615          * on the number of links. Typically called on create and delete.
4616          */
4617         public function touchLinks() {
4618                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4619                 $u->doUpdate();
4620
4621                 if ( $this->getNamespace() == NS_CATEGORY ) {
4622                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4623                         $u->doUpdate();
4624                 }
4625         }
4626
4627         /**
4628          * Get the last touched timestamp
4629          *
4630          * @param $db DatabaseBase: optional db
4631          * @return String last-touched timestamp
4632          */
4633         public function getTouched( $db = null ) {
4634                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
4635                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4636                 return $touched;
4637         }
4638
4639         /**
4640          * Get the timestamp when this page was updated since the user last saw it.
4641          *
4642          * @param $user User
4643          * @return String|Null
4644          */
4645         public function getNotificationTimestamp( $user = null ) {
4646                 global $wgUser, $wgShowUpdatedMarker;
4647                 // Assume current user if none given
4648                 if ( !$user ) {
4649                         $user = $wgUser;
4650                 }
4651                 // Check cache first
4652                 $uid = $user->getId();
4653                 // avoid isset here, as it'll return false for null entries
4654                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4655                         return $this->mNotificationTimestamp[$uid];
4656                 }
4657                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4658                         $this->mNotificationTimestamp[$uid] = false;
4659                         return $this->mNotificationTimestamp[$uid];
4660                 }
4661                 // Don't cache too much!
4662                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4663                         $this->mNotificationTimestamp = array();
4664                 }
4665                 $dbr = wfGetDB( DB_SLAVE );
4666                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4667                         'wl_notificationtimestamp',
4668                         array(
4669                                 'wl_user' => $user->getId(),
4670                                 'wl_namespace' => $this->getNamespace(),
4671                                 'wl_title' => $this->getDBkey(),
4672                         ),
4673                         __METHOD__
4674                 );
4675                 return $this->mNotificationTimestamp[$uid];
4676         }
4677
4678         /**
4679          * Generate strings used for xml 'id' names in monobook tabs
4680          *
4681          * @param string $prepend defaults to 'nstab-'
4682          * @return String XML 'id' name
4683          */
4684         public function getNamespaceKey( $prepend = 'nstab-' ) {
4685                 global $wgContLang;
4686                 // Gets the subject namespace if this title
4687                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4688                 // Checks if canonical namespace name exists for namespace
4689                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4690                         // Uses canonical namespace name
4691                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4692                 } else {
4693                         // Uses text of namespace
4694                         $namespaceKey = $this->getSubjectNsText();
4695                 }
4696                 // Makes namespace key lowercase
4697                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4698                 // Uses main
4699                 if ( $namespaceKey == '' ) {
4700                         $namespaceKey = 'main';
4701                 }
4702                 // Changes file to image for backwards compatibility
4703                 if ( $namespaceKey == 'file' ) {
4704                         $namespaceKey = 'image';
4705                 }
4706                 return $prepend . $namespaceKey;
4707         }
4708
4709         /**
4710          * Get all extant redirects to this Title
4711          *
4712          * @param int|Null $ns Single namespace to consider; NULL to consider all namespaces
4713          * @return Title[] Array of Title redirects to this title
4714          */
4715         public function getRedirectsHere( $ns = null ) {
4716                 $redirs = array();
4717
4718                 $dbr = wfGetDB( DB_SLAVE );
4719                 $where = array(
4720                         'rd_namespace' => $this->getNamespace(),
4721                         'rd_title' => $this->getDBkey(),
4722                         'rd_from = page_id'
4723                 );
4724                 if ( $this->isExternal() ) {
4725                         $where['rd_interwiki'] = $this->getInterwiki();
4726                 } else {
4727                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4728                 }
4729                 if ( !is_null( $ns ) ) {
4730                         $where['page_namespace'] = $ns;
4731                 }
4732
4733                 $res = $dbr->select(
4734                         array( 'redirect', 'page' ),
4735                         array( 'page_namespace', 'page_title' ),
4736                         $where,
4737                         __METHOD__
4738                 );
4739
4740                 foreach ( $res as $row ) {
4741                         $redirs[] = self::newFromRow( $row );
4742                 }
4743                 return $redirs;
4744         }
4745
4746         /**
4747          * Check if this Title is a valid redirect target
4748          *
4749          * @return Bool
4750          */
4751         public function isValidRedirectTarget() {
4752                 global $wgInvalidRedirectTargets;
4753
4754                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4755                 if ( $this->isSpecial( 'Userlogout' ) ) {
4756                         return false;
4757                 }
4758
4759                 foreach ( $wgInvalidRedirectTargets as $target ) {
4760                         if ( $this->isSpecial( $target ) ) {
4761                                 return false;
4762                         }
4763                 }
4764
4765                 return true;
4766         }
4767
4768         /**
4769          * Get a backlink cache object
4770          *
4771          * @return BacklinkCache
4772          */
4773         public function getBacklinkCache() {
4774                 return BacklinkCache::get( $this );
4775         }
4776
4777         /**
4778          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4779          *
4780          * @return Boolean
4781          */
4782         public function canUseNoindex() {
4783                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4784
4785                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4786                         ? $wgContentNamespaces
4787                         : $wgExemptFromUserRobotsControl;
4788
4789                 return !in_array( $this->mNamespace, $bannedNamespaces );
4790
4791         }
4792
4793         /**
4794          * Returns the raw sort key to be used for categories, with the specified
4795          * prefix.  This will be fed to Collation::getSortKey() to get a
4796          * binary sortkey that can be used for actual sorting.
4797          *
4798          * @param string $prefix The prefix to be used, specified using
4799          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4800          *   prefix.
4801          * @return string
4802          */
4803         public function getCategorySortkey( $prefix = '' ) {
4804                 $unprefixed = $this->getText();
4805
4806                 // Anything that uses this hook should only depend
4807                 // on the Title object passed in, and should probably
4808                 // tell the users to run updateCollations.php --force
4809                 // in order to re-sort existing category relations.
4810                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4811                 if ( $prefix !== '' ) {
4812                         # Separate with a line feed, so the unprefixed part is only used as
4813                         # a tiebreaker when two pages have the exact same prefix.
4814                         # In UCA, tab is the only character that can sort above LF
4815                         # so we strip both of them from the original prefix.
4816                         $prefix = strtr( $prefix, "\n\t", '  ' );
4817                         return "$prefix\n$unprefixed";
4818                 }
4819                 return $unprefixed;
4820         }
4821
4822         /**
4823          * Get the language in which the content of this page is written in
4824          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4825          * e.g. $wgLang (such as special pages, which are in the user language).
4826          *
4827          * @since 1.18
4828          * @return Language
4829          */
4830         public function getPageLanguage() {
4831                 global $wgLang, $wgLanguageCode;
4832                 wfProfileIn( __METHOD__ );
4833                 if ( $this->isSpecialPage() ) {
4834                         // special pages are in the user language
4835                         wfProfileOut( __METHOD__ );
4836                         return $wgLang;
4837                 }
4838
4839                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4840                         // Note that this may depend on user settings, so the cache should be only per-request.
4841                         // NOTE: ContentHandler::getPageLanguage() may need to load the content to determine the page language!
4842                         // Checking $wgLanguageCode hasn't changed for the benefit of unit tests.
4843                         $contentHandler = ContentHandler::getForTitle( $this );
4844                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4845                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4846                 } else {
4847                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4848                 }
4849                 wfProfileOut( __METHOD__ );
4850                 return $langObj;
4851         }
4852
4853         /**
4854          * Get the language in which the content of this page is written when
4855          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4856          * e.g. $wgLang (such as special pages, which are in the user language).
4857          *
4858          * @since 1.20
4859          * @return Language
4860          */
4861         public function getPageViewLanguage() {
4862                 global $wgLang;
4863
4864                 if ( $this->isSpecialPage() ) {
4865                         // If the user chooses a variant, the content is actually
4866                         // in a language whose code is the variant code.
4867                         $variant = $wgLang->getPreferredVariant();
4868                         if ( $wgLang->getCode() !== $variant ) {
4869                                 return Language::factory( $variant );
4870                         }
4871
4872                         return $wgLang;
4873                 }
4874
4875                 //NOTE: can't be cached persistently, depends on user settings
4876                 //NOTE: ContentHandler::getPageViewLanguage() may need to load the content to determine the page language!
4877                 $contentHandler = ContentHandler::getForTitle( $this );
4878                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4879                 return $pageLang;
4880         }
4881
4882         /**
4883          * Get a list of rendered edit notices for this page.
4884          *
4885          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4886          * they will already be wrapped in paragraphs.
4887          *
4888          * @since 1.21
4889          * @param int $oldid Revision ID that's being edited
4890          * @return Array
4891          */
4892         public function getEditNotices( $oldid = 0 ) {
4893                 $notices = array();
4894
4895                 # Optional notices on a per-namespace and per-page basis
4896                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4897                 $editnotice_ns_message = wfMessage( $editnotice_ns );
4898                 if ( $editnotice_ns_message->exists() ) {
4899                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
4900                 }
4901                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4902                         $parts = explode( '/', $this->getDBkey() );
4903                         $editnotice_base = $editnotice_ns;
4904                         while ( count( $parts ) > 0 ) {
4905                                 $editnotice_base .= '-' . array_shift( $parts );
4906                                 $editnotice_base_msg = wfMessage( $editnotice_base );
4907                                 if ( $editnotice_base_msg->exists() ) {
4908                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
4909                                 }
4910                         }
4911                 } else {
4912                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
4913                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
4914                         $editnoticeMsg = wfMessage( $editnoticeText );
4915                         if ( $editnoticeMsg->exists() ) {
4916                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
4917                         }
4918                 }
4919
4920                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4921                 return $notices;
4922         }
4923 }