includes/Title.php

   1 <?php
   2 /**
   3  * Representation 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  *
  31  * @internal documentation reviewed 15 Mar 2010
  32  */
  33 class Title {
  34         /** @var MapCacheLRU */
  35         static private $titleCache = null;
  36
  37         /**
  38          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  39          * commonly used titles. On a batch operation this can become a memory leak
  40          * if not bounded. After hitting this many titles reset the cache.
  41          */
  42         const CACHE_MAX = 1000;
  43
  44         /**
  45          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  46          * to use the master DB
  47          */
  48         const GAID_FOR_UPDATE = 1;
  49
  50         /**
  51          * @name Private member variables
  52          * Please use the accessor functions instead.
  53          * @private
  54          */
  55         // @{
  56
  57         var $mTextform = '';              // /< Text form (spaces not underscores) of the main part
  58         var $mUrlform = '';               // /< URL-encoded form of the main part
  59         var $mDbkeyform = '';             // /< Main part with underscores
  60         var $mUserCaseDBKey;              // /< DB key with the initial letter in the case specified by the user
  61         var $mNamespace = NS_MAIN;        // /< Namespace index, i.e. one of the NS_xxxx constants
  62         var $mInterwiki = '';             // /< Interwiki prefix
  63         var $mFragment;                   // /< Title fragment (i.e. the bit after the #)
  64         var $mArticleID = -1;             // /< Article ID, fetched from the link cache on demand
  65         var $mLatestID = false;           // /< ID of most recent revision
  66         var $mContentModel = false;       // /< ID of the page's content model, i.e. one of the CONTENT_MODEL_XXX constants
  67         private $mEstimateRevisions;      // /< Estimated number of revisions; null of not loaded
  68         var $mRestrictions = array();     // /< Array of groups allowed to edit this article
  69         var $mOldRestrictions = false;
  70         var $mCascadeRestriction;         ///< Cascade restrictions on this page to included templates and images?
  71         var $mCascadingRestrictions;      // Caching the results of getCascadeProtectionSources
  72         var $mRestrictionsExpiry = array(); ///< When do the restrictions on this page expire?
  73         var $mHasCascadingRestrictions;   ///< Are cascading restrictions in effect on this page?
  74         var $mCascadeSources;             ///< Where are the cascading restrictions coming from on this page?
  75         var $mRestrictionsLoaded = false; ///< Boolean for initialisation on demand
  76         var $mPrefixedText = null;        ///< Text form including namespace/interwiki, initialised on demand
  77         var $mTitleProtection;            ///< Cached value for getTitleProtection (create protection)
  78         # Don't change the following default, NS_MAIN is hardcoded in several
  79         # places.  See bug 696.
  80         # Zero except in {{transclusion}} tags
  81         var $mDefaultNamespace = NS_MAIN; // /< Namespace index when there is no namespace
  82         var $mWatched = null;             // /< Is $wgUser watching this page? null if unfilled, accessed through userIsWatching()
  83         var $mLength = -1;                // /< The page length, 0 for special pages
  84         var $mRedirect = null;            // /< Is the article at this title a redirect?
  85         var $mNotificationTimestamp = array(); // /< Associative array of user ID -> timestamp/false
  86         var $mHasSubpage;                 // /< Whether a page has any subpages
  87         private $mPageLanguage = false;   // /< The (string) language code of the page's language and content code.
  88         // @}
  89
  90         /**
  91          * Constructor
  92          */
  93         /*protected*/ function __construct() { }
  94
  95         /**
  96          * Create a new Title from a prefixed DB key
  97          *
  98          * @param string $key the database key, which has underscores
  99          *      instead of spaces, possibly including namespace and
 100          *      interwiki prefixes
 101          * @return Title, or NULL on an error
 102          */
 103         public static function newFromDBkey( $key ) {
 104                 $t = new Title();
 105                 $t->mDbkeyform = $key;
 106                 if ( $t->secureAndSplit() ) {
 107                         return $t;
 108                 } else {
 109                         return null;
 110                 }
 111         }
 112
 113         /**
 114          * Create a new Title from text, such as what one would find in a link. De-
 115          * codes any HTML entities in the text.
 116          *
 117          * @param string $text the link text; spaces, prefixes, and an
 118          *   initial ':' indicating the main namespace are accepted.
 119          * @param int $defaultNamespace the namespace to use if none is specified
 120          *   by a prefix.  If you want to force a specific namespace even if
 121          *   $text might begin with a namespace prefix, use makeTitle() or
 122          *   makeTitleSafe().
 123          * @throws MWException
 124          * @return Title|null - Title or null on an error.
 125          */
 126         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 127                 if ( is_object( $text ) ) {
 128                         throw new MWException( 'Title::newFromText given an object' );
 129                 }
 130
 131                 $cache = self::getTitleCache();
 132
 133                 /**
 134                  * Wiki pages often contain multiple links to the same page.
 135                  * Title normalization and parsing can become expensive on
 136                  * pages with many links, so we can save a little time by
 137                  * caching them.
 138                  *
 139                  * In theory these are value objects and won't get changed...
 140                  */
 141                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 142                         return $cache->get( $text );
 143                 }
 144
 145                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 146                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 147
 148                 $t = new Title();
 149                 $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
 150                 $t->mDefaultNamespace = $defaultNamespace;
 151
 152                 if ( $t->secureAndSplit() ) {
 153                         if ( $defaultNamespace == NS_MAIN ) {
 154                                 $cache->set( $text, $t );
 155                         }
 156                         return $t;
 157                 } else {
 158                         $ret = null;
 159                         return $ret;
 160                 }
 161         }
 162
 163         /**
 164          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 165          *
 166          * Example of wrong and broken code:
 167          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 168          *
 169          * Example of right code:
 170          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 171          *
 172          * Create a new Title from URL-encoded text. Ensures that
 173          * the given title's length does not exceed the maximum.
 174          *
 175          * @param string $url the title, as might be taken from a URL
 176          * @return Title the new object, or NULL on an error
 177          */
 178         public static function newFromURL( $url ) {
 179                 $t = new Title();
 180
 181                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 182                 # but some URLs used it as a space replacement and they still come
 183                 # from some external search tools.
 184                 if ( strpos( self::legalChars(), '+' ) === false ) {
 185                         $url = str_replace( '+', ' ', $url );
 186                 }
 187
 188                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 189                 if ( $t->secureAndSplit() ) {
 190                         return $t;
 191                 } else {
 192                         return null;
 193                 }
 194         }
 195
 196         /**
 197          * @return MapCacheLRU
 198          */
 199         private static function getTitleCache() {
 200                 if ( self::$titleCache == null ) {
 201                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 202                 }
 203                 return self::$titleCache;
 204         }
 205
 206         /**
 207          * Returns a list of fields that are to be selected for initializing Title objects or LinkCache entries.
 208          * Uses $wgContentHandlerUseDB to determine whether to include page_content_model.
 209          *
 210          * @return array
 211          */
 212         protected static function getSelectFields() {
 213                 global $wgContentHandlerUseDB;
 214
 215                 $fields = array(
 216                         'page_namespace', 'page_title', 'page_id',
 217                         'page_len', 'page_is_redirect', 'page_latest',
 218                 );
 219
 220                 if ( $wgContentHandlerUseDB ) {
 221                         $fields[] = 'page_content_model';
 222                 }
 223
 224                 return $fields;
 225         }
 226
 227         /**
 228          * Create a new Title from an article ID
 229          *
 230          * @param int $id the page_id corresponding to the Title to create
 231          * @param int $flags use Title::GAID_FOR_UPDATE to use master
 232          * @return Title|null the new object, or NULL on an error
 233          */
 234         public static function newFromID( $id, $flags = 0 ) {
 235                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 236                 $row = $db->selectRow(
 237                         'page',
 238                         self::getSelectFields(),
 239                         array( 'page_id' => $id ),
 240                         __METHOD__
 241                 );
 242                 if ( $row !== false ) {
 243                         $title = Title::newFromRow( $row );
 244                 } else {
 245                         $title = null;
 246                 }
 247                 return $title;
 248         }
 249
 250         /**
 251          * Make an array of titles from an array of IDs
 252          *
 253          * @param array $ids of Int Array of IDs
 254          * @return Array of Titles
 255          */
 256         public static function newFromIDs( $ids ) {
 257                 if ( !count( $ids ) ) {
 258                         return array();
 259                 }
 260                 $dbr = wfGetDB( DB_SLAVE );
 261
 262                 $res = $dbr->select(
 263                         'page',
 264                         self::getSelectFields(),
 265                         array( 'page_id' => $ids ),
 266                         __METHOD__
 267                 );
 268
 269                 $titles = array();
 270                 foreach ( $res as $row ) {
 271                         $titles[] = Title::newFromRow( $row );
 272                 }
 273                 return $titles;
 274         }
 275
 276         /**
 277          * Make a Title object from a DB row
 278          *
 279          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 280          * @return Title corresponding Title
 281          */
 282         public static function newFromRow( $row ) {
 283                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 284                 $t->loadFromRow( $row );
 285                 return $t;
 286         }
 287
 288         /**
 289          * Load Title object fields from a DB row.
 290          * If false is given, the title will be treated as non-existing.
 291          *
 292          * @param $row stdClass|bool database row
 293          */
 294         public function loadFromRow( $row ) {
 295                 if ( $row ) { // page found
 296                         if ( isset( $row->page_id ) ) {
 297                                 $this->mArticleID = (int)$row->page_id;
 298                         }
 299                         if ( isset( $row->page_len ) ) {
 300                                 $this->mLength = (int)$row->page_len;
 301                         }
 302                         if ( isset( $row->page_is_redirect ) ) {
 303                                 $this->mRedirect = (bool)$row->page_is_redirect;
 304                         }
 305                         if ( isset( $row->page_latest ) ) {
 306                                 $this->mLatestID = (int)$row->page_latest;
 307                         }
 308                         if ( isset( $row->page_content_model ) ) {
 309                                 $this->mContentModel = strval( $row->page_content_model );
 310                         } else {
 311                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 312                         }
 313                 } else { // page not found
 314                         $this->mArticleID = 0;
 315                         $this->mLength = 0;
 316                         $this->mRedirect = false;
 317                         $this->mLatestID = 0;
 318                         $this->mContentModel = false; # initialized lazily in getContentModel()
 319                 }
 320         }
 321
 322         /**
 323          * Create a new Title from a namespace index and a DB key.
 324          * It's assumed that $ns and $title are *valid*, for instance when
 325          * they came directly from the database or a special page name.
 326          * For convenience, spaces are converted to underscores so that
 327          * eg user_text fields can be used directly.
 328          *
 329          * @param int $ns the namespace of the article
 330          * @param string $title the unprefixed database key form
 331          * @param string $fragment the link fragment (after the "#")
 332          * @param string $interwiki the interwiki prefix
 333          * @return Title the new object
 334          */
 335         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 336                 $t = new Title();
 337                 $t->mInterwiki = $interwiki;
 338                 $t->mFragment = $fragment;
 339                 $t->mNamespace = $ns = intval( $ns );
 340                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 341                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 342                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 343                 $t->mTextform = str_replace( '_', ' ', $title );
 344                 $t->mContentModel = false; # initialized lazily in getContentModel()
 345                 return $t;
 346         }
 347
 348         /**
 349          * Create a new Title from a namespace index and a DB key.
 350          * The parameters will be checked for validity, which is a bit slower
 351          * than makeTitle() but safer for user-provided data.
 352          *
 353          * @param int $ns the namespace of the article
 354          * @param string $title database key form
 355          * @param string $fragment the link fragment (after the "#")
 356          * @param string $interwiki interwiki prefix
 357          * @return Title the new object, or NULL on an error
 358          */
 359         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 360                 if ( !MWNamespace::exists( $ns ) ) {
 361                         return null;
 362                 }
 363
 364                 $t = new Title();
 365                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 366                 if ( $t->secureAndSplit() ) {
 367                         return $t;
 368                 } else {
 369                         return null;
 370                 }
 371         }
 372
 373         /**
 374          * Create a new Title for the Main Page
 375          *
 376          * @return Title the new object
 377          */
 378         public static function newMainPage() {
 379                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 380                 // Don't give fatal errors if the message is broken
 381                 if ( !$title ) {
 382                         $title = Title::newFromText( 'Main Page' );
 383                 }
 384                 return $title;
 385         }
 386
 387         /**
 388          * Extract a redirect destination from a string and return the
 389          * Title, or null if the text doesn't contain a valid redirect
 390          * This will only return the very next target, useful for
 391          * the redirect table and other checks that don't need full recursion
 392          *
 393          * @param string $text Text with possible redirect
 394          * @return Title: The corresponding Title
 395          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 396          */
 397         public static function newFromRedirect( $text ) {
 398                 ContentHandler::deprecated( __METHOD__, '1.21' );
 399
 400                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 401                 return $content->getRedirectTarget();
 402         }
 403
 404         /**
 405          * Extract a redirect destination from a string and return the
 406          * Title, or null if the text doesn't contain a valid redirect
 407          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 408          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 409          *
 410          * @param string $text Text with possible redirect
 411          * @return Title
 412          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 413          */
 414         public static function newFromRedirectRecurse( $text ) {
 415                 ContentHandler::deprecated( __METHOD__, '1.21' );
 416
 417                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 418                 return $content->getUltimateRedirectTarget();
 419         }
 420
 421         /**
 422          * Extract a redirect destination from a string and return an
 423          * array of Titles, or null if the text doesn't contain a valid redirect
 424          * The last element in the array is the final destination after all redirects
 425          * have been resolved (up to $wgMaxRedirects times)
 426          *
 427          * @param string $text Text with possible redirect
 428          * @return Array of Titles, with the destination last
 429          * @deprecated since 1.21, use Content::getRedirectChain instead.
 430          */
 431         public static function newFromRedirectArray( $text ) {
 432                 ContentHandler::deprecated( __METHOD__, '1.21' );
 433
 434                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 435                 return $content->getRedirectChain();
 436         }
 437
 438         /**
 439          * Get the prefixed DB key associated with an ID
 440          *
 441          * @param int $id the page_id of the article
 442          * @return Title an object representing the article, or NULL if no such article was found
 443          */
 444         public static function nameOf( $id ) {
 445                 $dbr = wfGetDB( DB_SLAVE );
 446
 447                 $s = $dbr->selectRow(
 448                         'page',
 449                         array( 'page_namespace', 'page_title' ),
 450                         array( 'page_id' => $id ),
 451                         __METHOD__
 452                 );
 453                 if ( $s === false ) {
 454                         return null;
 455                 }
 456
 457                 $n = self::makeName( $s->page_namespace, $s->page_title );
 458                 return $n;
 459         }
 460
 461         /**
 462          * Get a regex character class describing the legal characters in a link
 463          *
 464          * @return String the list of characters, not delimited
 465          */
 466         public static function legalChars() {
 467                 global $wgLegalTitleChars;
 468                 return $wgLegalTitleChars;
 469         }
 470
 471         /**
 472          * Returns a simple regex that will match on characters and sequences invalid in titles.
 473          * Note that this doesn't pick up many things that could be wrong with titles, but that
 474          * replacing this regex with something valid will make many titles valid.
 475          *
 476          * @return String regex string
 477          */
 478         static function getTitleInvalidRegex() {
 479                 static $rxTc = false;
 480                 if ( !$rxTc ) {
 481                         # Matching titles will be held as illegal.
 482                         $rxTc = '/' .
 483                                 # Any character not allowed is forbidden...
 484                                 '[^' . self::legalChars() . ']' .
 485                                 # URL percent encoding sequences interfere with the ability
 486                                 # to round-trip titles -- you can't link to them consistently.
 487                                 '|%[0-9A-Fa-f]{2}' .
 488                                 # XML/HTML character references produce similar issues.
 489                                 '|&[A-Za-z0-9\x80-\xff]+;' .
 490                                 '|&#[0-9]+;' .
 491                                 '|&#x[0-9A-Fa-f]+;' .
 492                                 '/S';
 493                 }
 494
 495                 return $rxTc;
 496         }
 497
 498         /**
 499          * Utility method for converting a character sequence from bytes to Unicode.
 500          *
 501          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 502          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 503          *
 504          * @param string $byteClass
 505          * @return string
 506          */
 507         public static function convertByteClassToUnicodeClass( $byteClass ) {
 508                 $length = strlen( $byteClass );
 509                 // Input token queue
 510                 $x0 = $x1 = $x2 = '';
 511                 // Decoded queue
 512                 $d0 = $d1 = $d2 = '';
 513                 // Decoded integer codepoints
 514                 $ord0 = $ord1 = $ord2 = 0;
 515                 // Re-encoded queue
 516                 $r0 = $r1 = $r2 = '';
 517                 // Output
 518                 $out = '';
 519                 // Flags
 520                 $allowUnicode = false;
 521                 for ( $pos = 0; $pos < $length; $pos++ ) {
 522                         // Shift the queues down
 523                         $x2 = $x1;
 524                         $x1 = $x0;
 525                         $d2 = $d1;
 526                         $d1 = $d0;
 527                         $ord2 = $ord1;
 528                         $ord1 = $ord0;
 529                         $r2 = $r1;
 530                         $r1 = $r0;
 531                         // Load the current input token and decoded values
 532                         $inChar = $byteClass[$pos];
 533                         if ( $inChar == '\\' ) {
 534                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 535                                         $x0 = $inChar . $m[0];
 536                                         $d0 = chr( hexdec( $m[1] ) );
 537                                         $pos += strlen( $m[0] );
 538                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 539                                         $x0 = $inChar . $m[0];
 540                                         $d0 = chr( octdec( $m[0] ) );
 541                                         $pos += strlen( $m[0] );
 542                                 } elseif ( $pos + 1 >= $length ) {
 543                                         $x0 = $d0 = '\\';
 544                                 } else {
 545                                         $d0 = $byteClass[$pos + 1];
 546                                         $x0 = $inChar . $d0;
 547                                         $pos += 1;
 548                                 }
 549                         } else {
 550                                 $x0 = $d0 = $inChar;
 551                         }
 552                         $ord0 = ord( $d0 );
 553                         // Load the current re-encoded value
 554                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 555                                 $r0 = sprintf( '\x%02x', $ord0 );
 556                         } elseif ( $ord0 >= 0x80 ) {
 557                                 // Allow unicode if a single high-bit character appears
 558                                 $r0 = sprintf( '\x%02x', $ord0 );
 559                                 $allowUnicode = true;
 560                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 561                                 $r0 = '\\' . $d0;
 562                         } else {
 563                                 $r0 = $d0;
 564                         }
 565                         // Do the output
 566                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 567                                 // Range
 568                                 if ( $ord2 > $ord0 ) {
 569                                         // Empty range
 570                                 } elseif ( $ord0 >= 0x80 ) {
 571                                         // Unicode range
 572                                         $allowUnicode = true;
 573                                         if ( $ord2 < 0x80 ) {
 574                                                 // Keep the non-unicode section of the range
 575                                                 $out .= "$r2-\\x7F";
 576                                         }
 577                                 } else {
 578                                         // Normal range
 579                                         $out .= "$r2-$r0";
 580                                 }
 581                                 // Reset state to the initial value
 582                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 583                         } elseif ( $ord2 < 0x80 ) {
 584                                 // ASCII character
 585                                 $out .= $r2;
 586                         }
 587                 }
 588                 if ( $ord1 < 0x80 ) {
 589                         $out .= $r1;
 590                 }
 591                 if ( $ord0 < 0x80 ) {
 592                         $out .= $r0;
 593                 }
 594                 if ( $allowUnicode ) {
 595                         $out .= '\u0080-\uFFFF';
 596                 }
 597                 return $out;
 598         }
 599
 600         /**
 601          * Get a string representation of a title suitable for
 602          * including in a search index
 603          *
 604          * @param int $ns a namespace index
 605          * @param string $title text-form main part
 606          * @return String a stripped-down title string ready for the search index
 607          */
 608         public static function indexTitle( $ns, $title ) {
 609                 global $wgContLang;
 610
 611                 $lc = SearchEngine::legalSearchChars() . '&#;';
 612                 $t = $wgContLang->normalizeForSearch( $title );
 613                 $t = preg_replace( "/[^{$lc}]+/", ' ', $t );
 614                 $t = $wgContLang->lc( $t );
 615
 616                 # Handle 's, s'
 617                 $t = preg_replace( "/([{$lc}]+)'s( |$)/", "\\1 \\1's ", $t );
 618                 $t = preg_replace( "/([{$lc}]+)s'( |$)/", "\\1s ", $t );
 619
 620                 $t = preg_replace( "/\\s+/", ' ', $t );
 621
 622                 if ( $ns == NS_FILE ) {
 623                         $t = preg_replace( "/ (png|gif|jpg|jpeg|ogg)$/", "", $t );
 624                 }
 625                 return trim( $t );
 626         }
 627
 628         /**
 629          * Make a prefixed DB key from a DB key and a namespace index
 630          *
 631          * @param int $ns numerical representation of the namespace
 632          * @param string $title the DB key form the title
 633          * @param string $fragment The link fragment (after the "#")
 634          * @param string $interwiki The interwiki prefix
 635          * @return String the prefixed form of the title
 636          */
 637         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 638                 global $wgContLang;
 639
 640                 $namespace = $wgContLang->getNsText( $ns );
 641                 $name = $namespace == '' ? $title : "$namespace:$title";
 642                 if ( strval( $interwiki ) != '' ) {
 643                         $name = "$interwiki:$name";
 644                 }
 645                 if ( strval( $fragment ) != '' ) {
 646                         $name .= '#' . $fragment;
 647                 }
 648                 return $name;
 649         }
 650
 651         /**
 652          * Escape a text fragment, say from a link, for a URL
 653          *
 654          * @param string $fragment containing a URL or link fragment (after the "#")
 655          * @return String: escaped string
 656          */
 657         static function escapeFragmentForURL( $fragment ) {
 658                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 659                 # fragments appear not to work in IE (at least up to 7) or in at least
 660                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 661                 # to care if they aren't encoded.
 662                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 663         }
 664
 665         /**
 666          * Callback for usort() to do title sorts by (namespace, title)
 667          *
 668          * @param $a Title
 669          * @param $b Title
 670          *
 671          * @return Integer: result of string comparison, or namespace comparison
 672          */
 673         public static function compare( $a, $b ) {
 674                 if ( $a->getNamespace() == $b->getNamespace() ) {
 675                         return strcmp( $a->getText(), $b->getText() );
 676                 } else {
 677                         return $a->getNamespace() - $b->getNamespace();
 678                 }
 679         }
 680
 681         /**
 682          * Determine whether the object refers to a page within
 683          * this project.
 684          *
 685          * @return Bool TRUE if this is an in-project interwiki link or a wikilink, FALSE otherwise
 686          */
 687         public function isLocal() {
 688                 if ( $this->isExternal() ) {
 689                         $iw = Interwiki::fetch( $this->mInterwiki );
 690                         if ( $iw ) {
 691                                 return $iw->isLocal();
 692                         }
 693                 }
 694                 return true;
 695         }
 696
 697         /**
 698          * Is this Title interwiki?
 699          *
 700          * @return Bool
 701          */
 702         public function isExternal() {
 703                 return $this->mInterwiki !== '';
 704         }
 705
 706         /**
 707          * Get the interwiki prefix
 708          *
 709          * @return String Interwiki prefix
 710          */
 711         public function getInterwiki() {
 712                 return $this->mInterwiki;
 713         }
 714
 715         /**
 716          * Determine whether the object refers to a page within
 717          * this project and is transcludable.
 718          *
 719          * @return Bool TRUE if this is transcludable
 720          */
 721         public function isTrans() {
 722                 if ( !$this->isExternal() ) {
 723                         return false;
 724                 }
 725
 726                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 727         }
 728
 729         /**
 730          * Returns the DB name of the distant wiki which owns the object.
 731          *
 732          * @return String the DB name
 733          */
 734         public function getTransWikiID() {
 735                 if ( !$this->isExternal() ) {
 736                         return false;
 737                 }
 738
 739                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 740         }
 741
 742         /**
 743          * Get the text form (spaces not underscores) of the main part
 744          *
 745          * @return String Main part of the title
 746          */
 747         public function getText() {
 748                 return $this->mTextform;
 749         }
 750
 751         /**
 752          * Get the URL-encoded form of the main part
 753          *
 754          * @return String Main part of the title, URL-encoded
 755          */
 756         public function getPartialURL() {
 757                 return $this->mUrlform;
 758         }
 759
 760         /**
 761          * Get the main part with underscores
 762          *
 763          * @return String: Main part of the title, with underscores
 764          */
 765         public function getDBkey() {
 766                 return $this->mDbkeyform;
 767         }
 768
 769         /**
 770          * Get the DB key with the initial letter case as specified by the user
 771          *
 772          * @return String DB key
 773          */
 774         function getUserCaseDBKey() {
 775                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 776                         return $this->mUserCaseDBKey;
 777                 } else {
 778                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 779                         return $this->mDbkeyform;
 780                 }
 781         }
 782
 783         /**
 784          * Get the namespace index, i.e. one of the NS_xxxx constants.
 785          *
 786          * @return Integer: Namespace index
 787          */
 788         public function getNamespace() {
 789                 return $this->mNamespace;
 790         }
 791
 792         /**
 793          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 794          *
 795          * @throws MWException
 796          * @return String: Content model id
 797          */
 798         public function getContentModel() {
 799                 if ( !$this->mContentModel ) {
 800                         $linkCache = LinkCache::singleton();
 801                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 802                 }
 803
 804                 if ( !$this->mContentModel ) {
 805                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 806                 }
 807
 808                 if ( !$this->mContentModel ) {
 809                         throw new MWException( 'Failed to determine content model!' );
 810                 }
 811
 812                 return $this->mContentModel;
 813         }
 814
 815         /**
 816          * Convenience method for checking a title's content model name
 817          *
 818          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 819          * @return Boolean true if $this->getContentModel() == $id
 820          */
 821         public function hasContentModel( $id ) {
 822                 return $this->getContentModel() == $id;
 823         }
 824
 825         /**
 826          * Get the namespace text
 827          *
 828          * @return String: Namespace text
 829          */
 830         public function getNsText() {
 831                 global $wgContLang;
 832
 833                 if ( $this->isExternal() ) {
 834                         // This probably shouldn't even happen. ohh man, oh yuck.
 835                         // But for interwiki transclusion it sometimes does.
 836                         // Shit. Shit shit shit.
 837                         //
 838                         // Use the canonical namespaces if possible to try to
 839                         // resolve a foreign namespace.
 840                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 841                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 842                         }
 843                 }
 844
 845                 if ( $wgContLang->needsGenderDistinction() &&
 846                                 MWNamespace::hasGenderDistinction( $this->mNamespace ) ) {
 847                         $gender = GenderCache::singleton()->getGenderOf( $this->getText(), __METHOD__ );
 848                         return $wgContLang->getGenderNsText( $this->mNamespace, $gender );
 849                 }
 850
 851                 return $wgContLang->getNsText( $this->mNamespace );
 852         }
 853
 854         /**
 855          * Get the namespace text of the subject (rather than talk) page
 856          *
 857          * @return String Namespace text
 858          */
 859         public function getSubjectNsText() {
 860                 global $wgContLang;
 861                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 862         }
 863
 864         /**
 865          * Get the namespace text of the talk page
 866          *
 867          * @return String Namespace text
 868          */
 869         public function getTalkNsText() {
 870                 global $wgContLang;
 871                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
 872         }
 873
 874         /**
 875          * Could this title have a corresponding talk page?
 876          *
 877          * @return Bool TRUE or FALSE
 878          */
 879         public function canTalk() {
 880                 return MWNamespace::canTalk( $this->mNamespace );
 881         }
 882
 883         /**
 884          * Is this in a namespace that allows actual pages?
 885          *
 886          * @return Bool
 887          * @internal note -- uses hardcoded namespace index instead of constants
 888          */
 889         public function canExist() {
 890                 return $this->mNamespace >= NS_MAIN;
 891         }
 892
 893         /**
 894          * Can this title be added to a user's watchlist?
 895          *
 896          * @return Bool TRUE or FALSE
 897          */
 898         public function isWatchable() {
 899                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
 900         }
 901
 902         /**
 903          * Returns true if this is a special page.
 904          *
 905          * @return boolean
 906          */
 907         public function isSpecialPage() {
 908                 return $this->getNamespace() == NS_SPECIAL;
 909         }
 910
 911         /**
 912          * Returns true if this title resolves to the named special page
 913          *
 914          * @param string $name The special page name
 915          * @return boolean
 916          */
 917         public function isSpecial( $name ) {
 918                 if ( $this->isSpecialPage() ) {
 919                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
 920                         if ( $name == $thisName ) {
 921                                 return true;
 922                         }
 923                 }
 924                 return false;
 925         }
 926
 927         /**
 928          * If the Title refers to a special page alias which is not the local default, resolve
 929          * the alias, and localise the name as necessary.  Otherwise, return $this
 930          *
 931          * @return Title
 932          */
 933         public function fixSpecialName() {
 934                 if ( $this->isSpecialPage() ) {
 935                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
 936                         if ( $canonicalName ) {
 937                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
 938                                 if ( $localName != $this->mDbkeyform ) {
 939                                         return Title::makeTitle( NS_SPECIAL, $localName );
 940                                 }
 941                         }
 942                 }
 943                 return $this;
 944         }
 945
 946         /**
 947          * Returns true if the title is inside the specified namespace.
 948          *
 949          * Please make use of this instead of comparing to getNamespace()
 950          * This function is much more resistant to changes we may make
 951          * to namespaces than code that makes direct comparisons.
 952          * @param int $ns The namespace
 953          * @return bool
 954          * @since 1.19
 955          */
 956         public function inNamespace( $ns ) {
 957                 return MWNamespace::equals( $this->getNamespace(), $ns );
 958         }
 959
 960         /**
 961          * Returns true if the title is inside one of the specified namespaces.
 962          *
 963          * @param ...$namespaces The namespaces to check for
 964          * @return bool
 965          * @since 1.19
 966          */
 967         public function inNamespaces( /* ... */ ) {
 968                 $namespaces = func_get_args();
 969                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
 970                         $namespaces = $namespaces[0];
 971                 }
 972
 973                 foreach ( $namespaces as $ns ) {
 974                         if ( $this->inNamespace( $ns ) ) {
 975                                 return true;
 976                         }
 977                 }
 978
 979                 return false;
 980         }
 981
 982         /**
 983          * Returns true if the title has the same subject namespace as the
 984          * namespace specified.
 985          * For example this method will take NS_USER and return true if namespace
 986          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
 987          * as their subject namespace.
 988          *
 989          * This is MUCH simpler than individually testing for equivalence
 990          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
 991          * @since 1.19
 992          * @param $ns int
 993          * @return bool
 994          */
 995         public function hasSubjectNamespace( $ns ) {
 996                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
 997         }
 998
 999         /**
1000          * Is this Title in a namespace which contains content?
1001          * In other words, is this a content page, for the purposes of calculating
1002          * statistics, etc?
1003          *
1004          * @return Boolean
1005          */
1006         public function isContentPage() {
1007                 return MWNamespace::isContent( $this->getNamespace() );
1008         }
1009
1010         /**
1011          * Would anybody with sufficient privileges be able to move this page?
1012          * Some pages just aren't movable.
1013          *
1014          * @return Bool TRUE or FALSE
1015          */
1016         public function isMovable() {
1017                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1018                         // Interwiki title or immovable namespace. Hooks don't get to override here
1019                         return false;
1020                 }
1021
1022                 $result = true;
1023                 wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
1024                 return $result;
1025         }
1026
1027         /**
1028          * Is this the mainpage?
1029          * @note Title::newFromText seems to be sufficiently optimized by the title
1030          * cache that we don't need to over-optimize by doing direct comparisons and
1031          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1032          * ends up reporting something differently than $title->isMainPage();
1033          *
1034          * @since 1.18
1035          * @return Bool
1036          */
1037         public function isMainPage() {
1038                 return $this->equals( Title::newMainPage() );
1039         }
1040
1041         /**
1042          * Is this a subpage?
1043          *
1044          * @return Bool
1045          */
1046         public function isSubpage() {
1047                 return MWNamespace::hasSubpages( $this->mNamespace )
1048                         ? strpos( $this->getText(), '/' ) !== false
1049                         : false;
1050         }
1051
1052         /**
1053          * Is this a conversion table for the LanguageConverter?
1054          *
1055          * @return Bool
1056          */
1057         public function isConversionTable() {
1058                 // @todo ConversionTable should become a separate content model.
1059
1060                 return $this->getNamespace() == NS_MEDIAWIKI &&
1061                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1062         }
1063
1064         /**
1065          * Does that page contain wikitext, or it is JS, CSS or whatever?
1066          *
1067          * @return Bool
1068          */
1069         public function isWikitextPage() {
1070                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1071         }
1072
1073         /**
1074          * Could this page contain custom CSS or JavaScript for the global UI.
1075          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1076          * or CONTENT_MODEL_JAVASCRIPT.
1077          *
1078          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage() for that!
1079          *
1080          * Note that this method should not return true for pages that contain and show "inactive" CSS or JS.
1081          *
1082          * @return Bool
1083          */
1084         public function isCssOrJsPage() {
1085                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1086                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1087                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1088
1089                 #NOTE: this hook is also called in ContentHandler::getDefaultModel. It's called here again to make sure
1090                 #      hook functions can force this method to return true even outside the mediawiki namespace.
1091
1092                 wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ) );
1093
1094                 return $isCssOrJsPage;
1095         }
1096
1097         /**
1098          * Is this a .css or .js subpage of a user page?
1099          * @return Bool
1100          */
1101         public function isCssJsSubpage() {
1102                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1103                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1104                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1105         }
1106
1107         /**
1108          * Trim down a .css or .js subpage title to get the corresponding skin name
1109          *
1110          * @return string containing skin name from .css or .js subpage title
1111          */
1112         public function getSkinFromCssJsSubpage() {
1113                 $subpage = explode( '/', $this->mTextform );
1114                 $subpage = $subpage[count( $subpage ) - 1];
1115                 $lastdot = strrpos( $subpage, '.' );
1116                 if ( $lastdot === false ) {
1117                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1118                 }
1119                 return substr( $subpage, 0, $lastdot );
1120         }
1121
1122         /**
1123          * Is this a .css subpage of a user page?
1124          *
1125          * @return Bool
1126          */
1127         public function isCssSubpage() {
1128                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1129                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1130         }
1131
1132         /**
1133          * Is this a .js subpage of a user page?
1134          *
1135          * @return Bool
1136          */
1137         public function isJsSubpage() {
1138                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1139                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1140         }
1141
1142         /**
1143          * Is this a talk page of some sort?
1144          *
1145          * @return Bool
1146          */
1147         public function isTalkPage() {
1148                 return MWNamespace::isTalk( $this->getNamespace() );
1149         }
1150
1151         /**
1152          * Get a Title object associated with the talk page of this article
1153          *
1154          * @return Title the object for the talk page
1155          */
1156         public function getTalkPage() {
1157                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1158         }
1159
1160         /**
1161          * Get a title object associated with the subject page of this
1162          * talk page
1163          *
1164          * @return Title the object for the subject page
1165          */
1166         public function getSubjectPage() {
1167                 // Is this the same title?
1168                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1169                 if ( $this->getNamespace() == $subjectNS ) {
1170                         return $this;
1171                 }
1172                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1173         }
1174
1175         /**
1176          * Get the default namespace index, for when there is no namespace
1177          *
1178          * @return Int Default namespace index
1179          */
1180         public function getDefaultNamespace() {
1181                 return $this->mDefaultNamespace;
1182         }
1183
1184         /**
1185          * Get title for search index
1186          *
1187          * @return String a stripped-down title string ready for the
1188          *  search index
1189          */
1190         public function getIndexTitle() {
1191                 return Title::indexTitle( $this->mNamespace, $this->mTextform );
1192         }
1193
1194         /**
1195          * Get the Title fragment (i.e.\ the bit after the #) in text form
1196          *
1197          * @return String Title fragment
1198          */
1199         public function getFragment() {
1200                 return $this->mFragment;
1201         }
1202
1203         /**
1204          * Get the fragment in URL form, including the "#" character if there is one
1205          * @return String Fragment in URL form
1206          */
1207         public function getFragmentForURL() {
1208                 if ( $this->mFragment == '' ) {
1209                         return '';
1210                 } else {
1211                         return '#' . Title::escapeFragmentForURL( $this->mFragment );
1212                 }
1213         }
1214
1215         /**
1216          * Set the fragment for this title. Removes the first character from the
1217          * specified fragment before setting, so it assumes you're passing it with
1218          * an initial "#".
1219          *
1220          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1221          * Still in active use privately.
1222          *
1223          * @param string $fragment text
1224          */
1225         public function setFragment( $fragment ) {
1226                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1227         }
1228
1229         /**
1230          * Prefix some arbitrary text with the namespace or interwiki prefix
1231          * of this object
1232          *
1233          * @param string $name the text
1234          * @return String the prefixed text
1235          * @private
1236          */
1237         private function prefix( $name ) {
1238                 $p = '';
1239                 if ( $this->isExternal() ) {
1240                         $p = $this->mInterwiki . ':';
1241                 }
1242
1243                 if ( 0 != $this->mNamespace ) {
1244                         $p .= $this->getNsText() . ':';
1245                 }
1246                 return $p . $name;
1247         }
1248
1249         /**
1250          * Get the prefixed database key form
1251          *
1252          * @return String the prefixed title, with underscores and
1253          *  any interwiki and namespace prefixes
1254          */
1255         public function getPrefixedDBkey() {
1256                 $s = $this->prefix( $this->mDbkeyform );
1257                 $s = str_replace( ' ', '_', $s );
1258                 return $s;
1259         }
1260
1261         /**
1262          * Get the prefixed title with spaces.
1263          * This is the form usually used for display
1264          *
1265          * @return String the prefixed title, with spaces
1266          */
1267         public function getPrefixedText() {
1268                 if ( $this->mPrefixedText === null ) {
1269                         $s = $this->prefix( $this->mTextform );
1270                         $s = str_replace( '_', ' ', $s );
1271                         $this->mPrefixedText = $s;
1272                 }
1273                 return $this->mPrefixedText;
1274         }
1275
1276         /**
1277          * Return a string representation of this title
1278          *
1279          * @return String representation of this title
1280          */
1281         public function __toString() {
1282                 return $this->getPrefixedText();
1283         }
1284
1285         /**
1286          * Get the prefixed title with spaces, plus any fragment
1287          * (part beginning with '#')
1288          *
1289          * @return String the prefixed title, with spaces and the fragment, including '#'
1290          */
1291         public function getFullText() {
1292                 $text = $this->getPrefixedText();
1293                 if ( $this->mFragment != '' ) {
1294                         $text .= '#' . $this->mFragment;
1295                 }
1296                 return $text;
1297         }
1298
1299         /**
1300          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1301          *
1302          * @par Example:
1303          * @code
1304          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1305          * # returns: 'Foo'
1306          * @endcode
1307          *
1308          * @return String Root name
1309          * @since 1.20
1310          */
1311         public function getRootText() {
1312                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1313                         return $this->getText();
1314                 }
1315
1316                 return strtok( $this->getText(), '/' );
1317         }
1318
1319         /**
1320          * Get the root page name title, i.e. the leftmost part before any slashes
1321          *
1322          * @par Example:
1323          * @code
1324          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1325          * # returns: Title{User:Foo}
1326          * @endcode
1327          *
1328          * @return Title Root title
1329          * @since 1.20
1330          */
1331         public function getRootTitle() {
1332                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1333         }
1334
1335         /**
1336          * Get the base page name without a namespace, i.e. the part before the subpage name
1337          *
1338          * @par Example:
1339          * @code
1340          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1341          * # returns: 'Foo/Bar'
1342          * @endcode
1343          *
1344          * @return String Base name
1345          */
1346         public function getBaseText() {
1347                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1348                         return $this->getText();
1349                 }
1350
1351                 $parts = explode( '/', $this->getText() );
1352                 # Don't discard the real title if there's no subpage involved
1353                 if ( count( $parts ) > 1 ) {
1354                         unset( $parts[count( $parts ) - 1] );
1355                 }
1356                 return implode( '/', $parts );
1357         }
1358
1359         /**
1360          * Get the base page name title, i.e. the part before the subpage name
1361          *
1362          * @par Example:
1363          * @code
1364          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1365          * # returns: Title{User:Foo/Bar}
1366          * @endcode
1367          *
1368          * @return Title Base title
1369          * @since 1.20
1370          */
1371         public function getBaseTitle() {
1372                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1373         }
1374
1375         /**
1376          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1377          *
1378          * @par Example:
1379          * @code
1380          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1381          * # returns: "Baz"
1382          * @endcode
1383          *
1384          * @return String Subpage name
1385          */
1386         public function getSubpageText() {
1387                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1388                         return $this->mTextform;
1389                 }
1390                 $parts = explode( '/', $this->mTextform );
1391                 return $parts[count( $parts ) - 1];
1392         }
1393
1394         /**
1395          * Get the title for a subpage of the current page
1396          *
1397          * @par Example:
1398          * @code
1399          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1400          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1401          * @endcode
1402          *
1403          * @param string $text The subpage name to add to the title
1404          * @return Title Subpage title
1405          * @since 1.20
1406          */
1407         public function getSubpage( $text ) {
1408                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1409         }
1410
1411         /**
1412          * Get the HTML-escaped displayable text form.
1413          * Used for the title field in <a> tags.
1414          *
1415          * @return String the text, including any prefixes
1416          * @deprecated since 1.19
1417          */
1418         public function getEscapedText() {
1419                 wfDeprecated( __METHOD__, '1.19' );
1420                 return htmlspecialchars( $this->getPrefixedText() );
1421         }
1422
1423         /**
1424          * Get a URL-encoded form of the subpage text
1425          *
1426          * @return String URL-encoded subpage name
1427          */
1428         public function getSubpageUrlForm() {
1429                 $text = $this->getSubpageText();
1430                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1431                 return $text;
1432         }
1433
1434         /**
1435          * Get a URL-encoded title (not an actual URL) including interwiki
1436          *
1437          * @return String the URL-encoded form
1438          */
1439         public function getPrefixedURL() {
1440                 $s = $this->prefix( $this->mDbkeyform );
1441                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1442                 return $s;
1443         }
1444
1445         /**
1446          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1447          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1448          * second argument named variant. This was deprecated in favor
1449          * of passing an array of option with a "variant" key
1450          * Once $query2 is removed for good, this helper can be dropped
1451          * and the wfArrayToCgi moved to getLocalURL();
1452          *
1453          * @since 1.19 (r105919)
1454          * @param $query
1455          * @param $query2 bool
1456          * @return String
1457          */
1458         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1459                 if ( $query2 !== false ) {
1460                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1461                                 "method called with a second parameter is deprecated. Add your " .
1462                                 "parameter to an array passed as the first parameter.", "1.19" );
1463                 }
1464                 if ( is_array( $query ) ) {
1465                         $query = wfArrayToCgi( $query );
1466                 }
1467                 if ( $query2 ) {
1468                         if ( is_string( $query2 ) ) {
1469                                 // $query2 is a string, we will consider this to be
1470                                 // a deprecated $variant argument and add it to the query
1471                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1472                         } else {
1473                                 $query2 = wfArrayToCgi( $query2 );
1474                         }
1475                         // If we have $query content add a & to it first
1476                         if ( $query ) {
1477                                 $query .= '&';
1478                         }
1479                         // Now append the queries together
1480                         $query .= $query2;
1481                 }
1482                 return $query;
1483         }
1484
1485         /**
1486          * Get a real URL referring to this title, with interwiki link and
1487          * fragment
1488          *
1489          * See getLocalURL for the arguments.
1490          *
1491          * @see self::getLocalURL
1492          * @see wfExpandUrl
1493          * @param $query
1494          * @param $query2 bool
1495          * @param $proto Protocol type to use in URL
1496          * @return String the URL
1497          */
1498         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1499                 $query = self::fixUrlQueryArgs( $query, $query2 );
1500
1501                 # Hand off all the decisions on urls to getLocalURL
1502                 $url = $this->getLocalURL( $query );
1503
1504                 # Expand the url to make it a full url. Note that getLocalURL has the
1505                 # potential to output full urls for a variety of reasons, so we use
1506                 # wfExpandUrl instead of simply prepending $wgServer
1507                 $url = wfExpandUrl( $url, $proto );
1508
1509                 # Finally, add the fragment.
1510                 $url .= $this->getFragmentForURL();
1511
1512                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1513                 return $url;
1514         }
1515
1516         /**
1517          * Get a URL with no fragment or server name.  If this page is generated
1518          * with action=render, $wgServer is prepended.
1519          *
1520          * @param string|array $query an optional query string,
1521          *   not used for interwiki links. Can be specified as an associative array as well,
1522          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1523          *   Some query patterns will trigger various shorturl path replacements.
1524          * @param $query2 Mixed: An optional secondary query array. This one MUST
1525          *   be an array. If a string is passed it will be interpreted as a deprecated
1526          *   variant argument and urlencoded into a variant= argument.
1527          *   This second query argument will be added to the $query
1528          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1529          *   pair in the first parameter array instead.
1530          *
1531          * @return String the URL
1532          */
1533         public function getLocalURL( $query = '', $query2 = false ) {
1534                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1535
1536                 $query = self::fixUrlQueryArgs( $query, $query2 );
1537
1538                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1539                 if ( $interwiki ) {
1540                         $namespace = $this->getNsText();
1541                         if ( $namespace != '' ) {
1542                                 # Can this actually happen? Interwikis shouldn't be parsed.
1543                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1544                                 $namespace .= ':';
1545                         }
1546                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1547                         $url = wfAppendQuery( $url, $query );
1548                 } else {
1549                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1550                         if ( $query == '' ) {
1551                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1552                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1553                         } else {
1554                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1555                                 $url = false;
1556                                 $matches = array();
1557
1558                                 if ( !empty( $wgActionPaths )
1559                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1560                                 ) {
1561                                         $action = urldecode( $matches[2] );
1562                                         if ( isset( $wgActionPaths[$action] ) ) {
1563                                                 $query = $matches[1];
1564                                                 if ( isset( $matches[4] ) ) {
1565                                                         $query .= $matches[4];
1566                                                 }
1567                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1568                                                 if ( $query != '' ) {
1569                                                         $url = wfAppendQuery( $url, $query );
1570                                                 }
1571                                         }
1572                                 }
1573
1574                                 if ( $url === false
1575                                         && $wgVariantArticlePath
1576                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1577                                         && $this->getPageLanguage()->hasVariants()
1578                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1579                                 ) {
1580                                         $variant = urldecode( $matches[1] );
1581                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1582                                                 // Only do the variant replacement if the given variant is a valid
1583                                                 // variant for the page's language.
1584                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1585                                                 $url = str_replace( '$1', $dbkey, $url );
1586                                         }
1587                                 }
1588
1589                                 if ( $url === false ) {
1590                                         if ( $query == '-' ) {
1591                                                 $query = '';
1592                                         }
1593                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1594                                 }
1595                         }
1596
1597                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1598
1599                         // @todo FIXME: This causes breakage in various places when we
1600                         // actually expected a local URL and end up with dupe prefixes.
1601                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1602                                 $url = $wgServer . $url;
1603                         }
1604                 }
1605                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1606                 return $url;
1607         }
1608
1609         /**
1610          * Get a URL that's the simplest URL that will be valid to link, locally,
1611          * to the current Title.  It includes the fragment, but does not include
1612          * the server unless action=render is used (or the link is external).  If
1613          * there's a fragment but the prefixed text is empty, we just return a link
1614          * to the fragment.
1615          *
1616          * The result obviously should not be URL-escaped, but does need to be
1617          * HTML-escaped if it's being output in HTML.
1618          *
1619          * See getLocalURL for the arguments.
1620          *
1621          * @param $query
1622          * @param $query2 bool
1623          * @param $proto Protocol to use; setting this will cause a full URL to be used
1624          * @see self::getLocalURL
1625          * @return String the URL
1626          */
1627         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1628                 wfProfileIn( __METHOD__ );
1629                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1630                         $ret = $this->getFullURL( $query, $query2, $proto );
1631                 } elseif ( $this->getPrefixedText() === '' && $this->getFragment() !== '' ) {
1632                         $ret = $this->getFragmentForURL();
1633                 } else {
1634                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1635                 }
1636                 wfProfileOut( __METHOD__ );
1637                 return $ret;
1638         }
1639
1640         /**
1641          * Get an HTML-escaped version of the URL form, suitable for
1642          * using in a link, without a server name or fragment
1643          *
1644          * See getLocalURL for the arguments.
1645          *
1646          * @see self::getLocalURL
1647          * @param $query string
1648          * @param $query2 bool|string
1649          * @return String the URL
1650          * @deprecated since 1.19
1651          */
1652         public function escapeLocalURL( $query = '', $query2 = false ) {
1653                 wfDeprecated( __METHOD__, '1.19' );
1654                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1655         }
1656
1657         /**
1658          * Get an HTML-escaped version of the URL form, suitable for
1659          * using in a link, including the server name and fragment
1660          *
1661          * See getLocalURL for the arguments.
1662          *
1663          * @see self::getLocalURL
1664          * @return String the URL
1665          * @deprecated since 1.19
1666          */
1667         public function escapeFullURL( $query = '', $query2 = false ) {
1668                 wfDeprecated( __METHOD__, '1.19' );
1669                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1670         }
1671
1672         /**
1673          * Get the URL form for an internal link.
1674          * - Used in various Squid-related code, in case we have a different
1675          * internal hostname for the server from the exposed one.
1676          *
1677          * This uses $wgInternalServer to qualify the path, or $wgServer
1678          * if $wgInternalServer is not set. If the server variable used is
1679          * protocol-relative, the URL will be expanded to http://
1680          *
1681          * See getLocalURL for the arguments.
1682          *
1683          * @see self::getLocalURL
1684          * @return String the URL
1685          */
1686         public function getInternalURL( $query = '', $query2 = false ) {
1687                 global $wgInternalServer, $wgServer;
1688                 $query = self::fixUrlQueryArgs( $query, $query2 );
1689                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1690                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1691                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1692                 return $url;
1693         }
1694
1695         /**
1696          * Get the URL for a canonical link, for use in things like IRC and
1697          * e-mail notifications. Uses $wgCanonicalServer and the
1698          * GetCanonicalURL hook.
1699          *
1700          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1701          *
1702          * See getLocalURL for the arguments.
1703          *
1704          * @see self::getLocalURL
1705          * @return string The URL
1706          * @since 1.18
1707          */
1708         public function getCanonicalURL( $query = '', $query2 = false ) {
1709                 $query = self::fixUrlQueryArgs( $query, $query2 );
1710                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1711                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1712                 return $url;
1713         }
1714
1715         /**
1716          * HTML-escaped version of getCanonicalURL()
1717          *
1718          * See getLocalURL for the arguments.
1719          *
1720          * @see self::getLocalURL
1721          * @since 1.18
1722          * @return string
1723          * @deprecated since 1.19
1724          */
1725         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1726                 wfDeprecated( __METHOD__, '1.19' );
1727                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1728         }
1729
1730         /**
1731          * Get the edit URL for this Title
1732          *
1733          * @return String the URL, or a null string if this is an
1734          *  interwiki link
1735          */
1736         public function getEditURL() {
1737                 if ( $this->isExternal() ) {
1738                         return '';
1739                 }
1740                 $s = $this->getLocalURL( 'action=edit' );
1741
1742                 return $s;
1743         }
1744
1745         /**
1746          * Is $wgUser watching this page?
1747          *
1748          * @deprecated in 1.20; use User::isWatched() instead.
1749          * @return Bool
1750          */
1751         public function userIsWatching() {
1752                 global $wgUser;
1753
1754                 if ( is_null( $this->mWatched ) ) {
1755                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1756                                 $this->mWatched = false;
1757                         } else {
1758                                 $this->mWatched = $wgUser->isWatched( $this );
1759                         }
1760                 }
1761                 return $this->mWatched;
1762         }
1763
1764         /**
1765          * Can $wgUser read this page?
1766          *
1767          * @deprecated in 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1768          * @return Bool
1769          * @todo fold these checks into userCan()
1770          */
1771         public function userCanRead() {
1772                 wfDeprecated( __METHOD__, '1.19' );
1773                 return $this->userCan( 'read' );
1774         }
1775
1776         /**
1777          * Can $user perform $action on this page?
1778          * This skips potentially expensive cascading permission checks
1779          * as well as avoids expensive error formatting
1780          *
1781          * Suitable for use for nonessential UI controls in common cases, but
1782          * _not_ for functional access control.
1783          *
1784          * May provide false positives, but should never provide a false negative.
1785          *
1786          * @param string $action action that permission needs to be checked for
1787          * @param $user User to check (since 1.19); $wgUser will be used if not
1788          *              provided.
1789          * @return Bool
1790          */
1791         public function quickUserCan( $action, $user = null ) {
1792                 return $this->userCan( $action, $user, false );
1793         }
1794
1795         /**
1796          * Can $user perform $action on this page?
1797          *
1798          * @param string $action action that permission needs to be checked for
1799          * @param $user User to check (since 1.19); $wgUser will be used if not
1800          *   provided.
1801          * @param bool $doExpensiveQueries Set this to false to avoid doing
1802          *   unnecessary queries.
1803          * @return Bool
1804          */
1805         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1806                 if ( !$user instanceof User ) {
1807                         global $wgUser;
1808                         $user = $wgUser;
1809                 }
1810                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries, true ) );
1811         }
1812
1813         /**
1814          * Can $user perform $action on this page?
1815          *
1816          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1817          *
1818          * @param string $action action that permission needs to be checked for
1819          * @param $user User to check
1820          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1821          *   queries by skipping checks for cascading protections and user blocks.
1822          * @param array $ignoreErrors of Strings Set this to a list of message keys
1823          *   whose corresponding errors may be ignored.
1824          * @return Array of arguments to wfMessage to explain permissions problems.
1825          */
1826         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
1827                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1828
1829                 // Remove the errors being ignored.
1830                 foreach ( $errors as $index => $error ) {
1831                         $error_key = is_array( $error ) ? $error[0] : $error;
1832
1833                         if ( in_array( $error_key, $ignoreErrors ) ) {
1834                                 unset( $errors[$index] );
1835                         }
1836                 }
1837
1838                 return $errors;
1839         }
1840
1841         /**
1842          * Permissions checks that fail most often, and which are easiest to test.
1843          *
1844          * @param string $action the action to check
1845          * @param $user User user to check
1846          * @param array $errors list of current errors
1847          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1848          * @param $short Boolean short circuit on first error
1849          *
1850          * @return Array list of errors
1851          */
1852         private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1853                 if ( !wfRunHooks( 'TitleQuickPermissions', array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) ) ) {
1854                         return $errors;
1855                 }
1856
1857                 if ( $action == 'create' ) {
1858                         if (
1859                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1860                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1861                         ) {
1862                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1863                         }
1864                 } elseif ( $action == 'move' ) {
1865                         if ( !$user->isAllowed( 'move-rootuserpages' )
1866                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1867                                 // Show user page-specific message only if the user can move other pages
1868                                 $errors[] = array( 'cant-move-user-page' );
1869                         }
1870
1871                         // Check if user is allowed to move files if it's a file
1872                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1873                                 $errors[] = array( 'movenotallowedfile' );
1874                         }
1875
1876                         if ( !$user->isAllowed( 'move' ) ) {
1877                                 // User can't move anything
1878                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1879                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1880                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1881                                         // custom message if logged-in users without any special rights can move
1882                                         $errors[] = array( 'movenologintext' );
1883                                 } else {
1884                                         $errors[] = array( 'movenotallowed' );
1885                                 }
1886                         }
1887                 } elseif ( $action == 'move-target' ) {
1888                         if ( !$user->isAllowed( 'move' ) ) {
1889                                 // User can't move anything
1890                                 $errors[] = array( 'movenotallowed' );
1891                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1892                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1893                                 // Show user page-specific message only if the user can move other pages
1894                                 $errors[] = array( 'cant-move-to-user-page' );
1895                         }
1896                 } elseif ( !$user->isAllowed( $action ) ) {
1897                         $errors[] = $this->missingPermissionError( $action, $short );
1898                 }
1899
1900                 return $errors;
1901         }
1902
1903         /**
1904          * Add the resulting error code to the errors array
1905          *
1906          * @param array $errors list of current errors
1907          * @param $result Mixed result of errors
1908          *
1909          * @return Array list of errors
1910          */
1911         private function resultToError( $errors, $result ) {
1912                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1913                         // A single array representing an error
1914                         $errors[] = $result;
1915                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
1916                         // A nested array representing multiple errors
1917                         $errors = array_merge( $errors, $result );
1918                 } elseif ( $result !== '' && is_string( $result ) ) {
1919                         // A string representing a message-id
1920                         $errors[] = array( $result );
1921                 } elseif ( $result === false ) {
1922                         // a generic "We don't want them to do that"
1923                         $errors[] = array( 'badaccess-group0' );
1924                 }
1925                 return $errors;
1926         }
1927
1928         /**
1929          * Check various permission hooks
1930          *
1931          * @param string $action the action to check
1932          * @param $user User user to check
1933          * @param array $errors list of current errors
1934          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1935          * @param $short Boolean short circuit on first error
1936          *
1937          * @return Array list of errors
1938          */
1939         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
1940                 // Use getUserPermissionsErrors instead
1941                 $result = '';
1942                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
1943                         return $result ? array() : array( array( 'badaccess-group0' ) );
1944                 }
1945                 // Check getUserPermissionsErrors hook
1946                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
1947                         $errors = $this->resultToError( $errors, $result );
1948                 }
1949                 // Check getUserPermissionsErrorsExpensive hook
1950                 if (
1951                         $doExpensiveQueries
1952                         && !( $short && count( $errors ) > 0 )
1953                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
1954                 ) {
1955                         $errors = $this->resultToError( $errors, $result );
1956                 }
1957
1958                 return $errors;
1959         }
1960
1961         /**
1962          * Check permissions on special pages & namespaces
1963          *
1964          * @param string $action the action to check
1965          * @param $user User user to check
1966          * @param array $errors list of current errors
1967          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1968          * @param $short Boolean short circuit on first error
1969          *
1970          * @return Array list of errors
1971          */
1972         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1973                 # Only 'createaccount' can be performed on special pages,
1974                 # which don't actually exist in the DB.
1975                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
1976                         $errors[] = array( 'ns-specialprotected' );
1977                 }
1978
1979                 # Check $wgNamespaceProtection for restricted namespaces
1980                 if ( $this->isNamespaceProtected( $user ) ) {
1981                         $ns = $this->mNamespace == NS_MAIN ?
1982                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
1983                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
1984                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
1985                 }
1986
1987                 return $errors;
1988         }
1989
1990         /**
1991          * Check CSS/JS sub-page permissions
1992          *
1993          * @param string $action the action to check
1994          * @param $user User user to check
1995          * @param array $errors list of current errors
1996          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1997          * @param $short Boolean short circuit on first error
1998          *
1999          * @return Array list of errors
2000          */
2001         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2002                 # Protect css/js subpages of user pages
2003                 # XXX: this might be better using restrictions
2004                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2005                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2006                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2007                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2008                                         $errors[] = array( 'mycustomcssprotected' );
2009                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2010                                         $errors[] = array( 'mycustomjsprotected' );
2011                                 }
2012                         } else {
2013                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2014                                         $errors[] = array( 'customcssprotected' );
2015                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2016                                         $errors[] = array( 'customjsprotected' );
2017                                 }
2018                         }
2019                 }
2020
2021                 return $errors;
2022         }
2023
2024         /**
2025          * Check against page_restrictions table requirements on this
2026          * page. The user must possess all required rights for this
2027          * action.
2028          *
2029          * @param string $action the action to check
2030          * @param $user User user to check
2031          * @param array $errors list of current errors
2032          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2033          * @param $short Boolean short circuit on first error
2034          *
2035          * @return Array list of errors
2036          */
2037         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2038                 foreach ( $this->getRestrictions( $action ) as $right ) {
2039                         // Backwards compatibility, rewrite sysop -> editprotected
2040                         if ( $right == 'sysop' ) {
2041                                 $right = 'editprotected';
2042                         }
2043                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2044                         if ( $right == 'autoconfirmed' ) {
2045                                 $right = 'editsemiprotected';
2046                         }
2047                         if ( $right == '' ) {
2048                                 continue;
2049                         }
2050                         if ( !$user->isAllowed( $right ) ) {
2051                                 $errors[] = array( 'protectedpagetext', $right );
2052                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2053                                 $errors[] = array( 'protectedpagetext', 'protect' );
2054                         }
2055                 }
2056
2057                 return $errors;
2058         }
2059
2060         /**
2061          * Check restrictions on cascading pages.
2062          *
2063          * @param string $action the action to check
2064          * @param $user User to check
2065          * @param array $errors list of current errors
2066          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2067          * @param $short Boolean short circuit on first error
2068          *
2069          * @return Array list of errors
2070          */
2071         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2072                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2073                         # We /could/ use the protection level on the source page, but it's
2074                         # fairly ugly as we have to establish a precedence hierarchy for pages
2075                         # included by multiple cascade-protected pages. So just restrict
2076                         # it to people with 'protect' permission, as they could remove the
2077                         # protection anyway.
2078                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2079                         # Cascading protection depends on more than this page...
2080                         # Several cascading protected pages may include this page...
2081                         # Check each cascading level
2082                         # This is only for protection restrictions, not for all actions
2083                         if ( isset( $restrictions[$action] ) ) {
2084                                 foreach ( $restrictions[$action] as $right ) {
2085                                         // Backwards compatibility, rewrite sysop -> editprotected
2086                                         if ( $right == 'sysop' ) {
2087                                                 $right = 'editprotected';
2088                                         }
2089                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2090                                         if ( $right == 'autoconfirmed' ) {
2091                                                 $right = 'editsemiprotected';
2092                                         }
2093                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2094                                                 $pages = '';
2095                                                 foreach ( $cascadingSources as $page ) {
2096                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2097                                                 }
2098                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2099                                         }
2100                                 }
2101                         }
2102                 }
2103
2104                 return $errors;
2105         }
2106
2107         /**
2108          * Check action permissions not already checked in checkQuickPermissions
2109          *
2110          * @param string $action the action to check
2111          * @param $user User to check
2112          * @param array $errors list of current errors
2113          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2114          * @param $short Boolean short circuit on first error
2115          *
2116          * @return Array list of errors
2117          */
2118         private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2119                 global $wgDeleteRevisionsLimit, $wgLang;
2120
2121                 if ( $action == 'protect' ) {
2122                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $doExpensiveQueries, true ) ) ) {
2123                                 // If they can't edit, they shouldn't protect.
2124                                 $errors[] = array( 'protect-cantedit' );
2125                         }
2126                 } elseif ( $action == 'create' ) {
2127                         $title_protection = $this->getTitleProtection();
2128                         if ( $title_protection ) {
2129                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2130                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2131                                 }
2132                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2133                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2134                                 }
2135                                 if ( $title_protection['pt_create_perm'] == ''
2136                                         || !$user->isAllowed( $title_protection['pt_create_perm'] )
2137                                 ) {
2138                                         $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
2139                                 }
2140                         }
2141                 } elseif ( $action == 'move' ) {
2142                         // Check for immobile pages
2143                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2144                                 // Specific message for this case
2145                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2146                         } elseif ( !$this->isMovable() ) {
2147                                 // Less specific message for rarer cases
2148                                 $errors[] = array( 'immobile-source-page' );
2149                         }
2150                 } elseif ( $action == 'move-target' ) {
2151                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2152                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2153                         } elseif ( !$this->isMovable() ) {
2154                                 $errors[] = array( 'immobile-target-page' );
2155                         }
2156                 } elseif ( $action == 'delete' ) {
2157                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2158                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2159                         ) {
2160                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2161                         }
2162                 }
2163                 return $errors;
2164         }
2165
2166         /**
2167          * Check that the user isn't blocked from editing.
2168          *
2169          * @param string $action the action to check
2170          * @param $user User to check
2171          * @param array $errors list of current errors
2172          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2173          * @param $short Boolean short circuit on first error
2174          *
2175          * @return Array list of errors
2176          */
2177         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2178                 // Account creation blocks handled at userlogin.
2179                 // Unblocking handled in SpecialUnblock
2180                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2181                         return $errors;
2182                 }
2183
2184                 global $wgEmailConfirmToEdit;
2185
2186                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2187                         $errors[] = array( 'confirmedittext' );
2188                 }
2189
2190                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2191                         // Don't block the user from editing their own talk page unless they've been
2192                         // explicitly blocked from that too.
2193                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2194                         // @todo FIXME: Pass the relevant context into this function.
2195                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2196                 }
2197
2198                 return $errors;
2199         }
2200
2201         /**
2202          * Check that the user is allowed to read this page.
2203          *
2204          * @param string $action the action to check
2205          * @param $user User to check
2206          * @param array $errors list of current errors
2207          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2208          * @param $short Boolean short circuit on first error
2209          *
2210          * @return Array list of errors
2211          */
2212         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2213                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2214
2215                 $whitelisted = false;
2216                 if ( User::isEveryoneAllowed( 'read' ) ) {
2217                         # Shortcut for public wikis, allows skipping quite a bit of code
2218                         $whitelisted = true;
2219                 } elseif ( $user->isAllowed( 'read' ) ) {
2220                         # If the user is allowed to read pages, he is allowed to read all pages
2221                         $whitelisted = true;
2222                 } elseif ( $this->isSpecial( 'Userlogin' )
2223                         || $this->isSpecial( 'ChangePassword' )
2224                         || $this->isSpecial( 'PasswordReset' )
2225                 ) {
2226                         # Always grant access to the login page.
2227                         # Even anons need to be able to log in.
2228                         $whitelisted = true;
2229                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2230                         # Time to check the whitelist
2231                         # Only do these checks is there's something to check against
2232                         $name = $this->getPrefixedText();
2233                         $dbName = $this->getPrefixedDBkey();
2234
2235                         // Check for explicit whitelisting with and without underscores
2236                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2237                                 $whitelisted = true;
2238                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2239                                 # Old settings might have the title prefixed with
2240                                 # a colon for main-namespace pages
2241                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2242                                         $whitelisted = true;
2243                                 }
2244                         } elseif ( $this->isSpecialPage() ) {
2245                                 # If it's a special page, ditch the subpage bit and check again
2246                                 $name = $this->getDBkey();
2247                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2248                                 if ( $name ) {
2249                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2250                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2251                                                 $whitelisted = true;
2252                                         }
2253                                 }
2254                         }
2255                 }
2256
2257                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2258                         $name = $this->getPrefixedText();
2259                         // Check for regex whitelisting
2260                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2261                                 if ( preg_match( $listItem, $name ) ) {
2262                                         $whitelisted = true;
2263                                         break;
2264                                 }
2265                         }
2266                 }
2267
2268                 if ( !$whitelisted ) {
2269                         # If the title is not whitelisted, give extensions a chance to do so...
2270                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2271                         if ( !$whitelisted ) {
2272                                 $errors[] = $this->missingPermissionError( $action, $short );
2273                         }
2274                 }
2275
2276                 return $errors;
2277         }
2278
2279         /**
2280          * Get a description array when the user doesn't have the right to perform
2281          * $action (i.e. when User::isAllowed() returns false)
2282          *
2283          * @param string $action the action to check
2284          * @param $short Boolean short circuit on first error
2285          * @return Array list of errors
2286          */
2287         private function missingPermissionError( $action, $short ) {
2288                 // We avoid expensive display logic for quickUserCan's and such
2289                 if ( $short ) {
2290                         return array( 'badaccess-group0' );
2291                 }
2292
2293                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2294                         User::getGroupsWithPermission( $action ) );
2295
2296                 if ( count( $groups ) ) {
2297                         global $wgLang;
2298                         return array(
2299                                 'badaccess-groups',
2300                                 $wgLang->commaList( $groups ),
2301                                 count( $groups )
2302                         );
2303                 } else {
2304                         return array( 'badaccess-group0' );
2305                 }
2306         }
2307
2308         /**
2309          * Can $user perform $action on this page? This is an internal function,
2310          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2311          * checks on wfReadOnly() and blocks)
2312          *
2313          * @param string $action action that permission needs to be checked for
2314          * @param $user User to check
2315          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2316          * @param bool $short Set this to true to stop after the first permission error.
2317          * @return Array of arrays of the arguments to wfMessage to explain permissions problems.
2318          */
2319         protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
2320                 wfProfileIn( __METHOD__ );
2321
2322                 # Read has special handling
2323                 if ( $action == 'read' ) {
2324                         $checks = array(
2325                                 'checkPermissionHooks',
2326                                 'checkReadPermissions',
2327                         );
2328                 } else {
2329                         $checks = array(
2330                                 'checkQuickPermissions',
2331                                 'checkPermissionHooks',
2332                                 'checkSpecialsAndNSPermissions',
2333                                 'checkCSSandJSPermissions',
2334                                 'checkPageRestrictions',
2335                                 'checkCascadingSourcesRestrictions',
2336                                 'checkActionPermissions',
2337                                 'checkUserBlock'
2338                         );
2339                 }
2340
2341                 $errors = array();
2342                 while ( count( $checks ) > 0 &&
2343                                 !( $short && count( $errors ) > 0 ) ) {
2344                         $method = array_shift( $checks );
2345                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2346                 }
2347
2348                 wfProfileOut( __METHOD__ );
2349                 return $errors;
2350         }
2351
2352         /**
2353          * Get a filtered list of all restriction types supported by this wiki.
2354          * @param bool $exists True to get all restriction types that apply to
2355          * titles that do exist, False for all restriction types that apply to
2356          * titles that do not exist
2357          * @return array
2358          */
2359         public static function getFilteredRestrictionTypes( $exists = true ) {
2360                 global $wgRestrictionTypes;
2361                 $types = $wgRestrictionTypes;
2362                 if ( $exists ) {
2363                         # Remove the create restriction for existing titles
2364                         $types = array_diff( $types, array( 'create' ) );
2365                 } else {
2366                         # Only the create and upload restrictions apply to non-existing titles
2367                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2368                 }
2369                 return $types;
2370         }
2371
2372         /**
2373          * Returns restriction types for the current Title
2374          *
2375          * @return array applicable restriction types
2376          */
2377         public function getRestrictionTypes() {
2378                 if ( $this->isSpecialPage() ) {
2379                         return array();
2380                 }
2381
2382                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2383
2384                 if ( $this->getNamespace() != NS_FILE ) {
2385                         # Remove the upload restriction for non-file titles
2386                         $types = array_diff( $types, array( 'upload' ) );
2387                 }
2388
2389                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2390
2391                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2392                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2393
2394                 return $types;
2395         }
2396
2397         /**
2398          * Is this title subject to title protection?
2399          * Title protection is the one applied against creation of such title.
2400          *
2401          * @return Mixed An associative array representing any existent title
2402          *   protection, or false if there's none.
2403          */
2404         private function getTitleProtection() {
2405                 // Can't protect pages in special namespaces
2406                 if ( $this->getNamespace() < 0 ) {
2407                         return false;
2408                 }
2409
2410                 // Can't protect pages that exist.
2411                 if ( $this->exists() ) {
2412                         return false;
2413                 }
2414
2415                 if ( !isset( $this->mTitleProtection ) ) {
2416                         $dbr = wfGetDB( DB_SLAVE );
2417                         $res = $dbr->select(
2418                                 'protected_titles',
2419                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2420                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2421                                 __METHOD__
2422                         );
2423
2424                         // fetchRow returns false if there are no rows.
2425                         $this->mTitleProtection = $dbr->fetchRow( $res );
2426                 }
2427                 return $this->mTitleProtection;
2428         }
2429
2430         /**
2431          * Update the title protection status
2432          *
2433          * @deprecated in 1.19; use WikiPage::doUpdateRestrictions() instead.
2434          * @param $create_perm String Permission required for creation
2435          * @param string $reason Reason for protection
2436          * @param string $expiry Expiry timestamp
2437          * @return boolean true
2438          */
2439         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2440                 wfDeprecated( __METHOD__, '1.19' );
2441
2442                 global $wgUser;
2443
2444                 $limit = array( 'create' => $create_perm );
2445                 $expiry = array( 'create' => $expiry );
2446
2447                 $page = WikiPage::factory( $this );
2448                 $cascade = false;
2449                 $status = $page->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $wgUser );
2450
2451                 return $status->isOK();
2452         }
2453
2454         /**
2455          * Remove any title protection due to page existing
2456          */
2457         public function deleteTitleProtection() {
2458                 $dbw = wfGetDB( DB_MASTER );
2459
2460                 $dbw->delete(
2461                         'protected_titles',
2462                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2463                         __METHOD__
2464                 );
2465                 $this->mTitleProtection = false;
2466         }
2467
2468         /**
2469          * Is this page "semi-protected" - the *only* protection levels are listed
2470          * in $wgSemiprotectedRestrictionLevels?
2471          *
2472          * @param string $action Action to check (default: edit)
2473          * @return Bool
2474          */
2475         public function isSemiProtected( $action = 'edit' ) {
2476                 global $wgSemiprotectedRestrictionLevels;
2477
2478                 $restrictions = $this->getRestrictions( $action );
2479                 $semi = $wgSemiprotectedRestrictionLevels;
2480                 if ( !$restrictions || !$semi ) {
2481                         // Not protected, or all protection is full protection
2482                         return false;
2483                 }
2484
2485                 // Remap autoconfirmed to editsemiprotected for BC
2486                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2487                         $semi[$key] = 'editsemiprotected';
2488                 }
2489                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2490                         $restrictions[$key] = 'editsemiprotected';
2491                 }
2492
2493                 return !array_diff( $restrictions, $semi );
2494         }
2495
2496         /**
2497          * Does the title correspond to a protected article?
2498          *
2499          * @param string $action the action the page is protected from,
2500          * by default checks all actions.
2501          * @return Bool
2502          */
2503         public function isProtected( $action = '' ) {
2504                 global $wgRestrictionLevels;
2505
2506                 $restrictionTypes = $this->getRestrictionTypes();
2507
2508                 # Special pages have inherent protection
2509                 if ( $this->isSpecialPage() ) {
2510                         return true;
2511                 }
2512
2513                 # Check regular protection levels
2514                 foreach ( $restrictionTypes as $type ) {
2515                         if ( $action == $type || $action == '' ) {
2516                                 $r = $this->getRestrictions( $type );
2517                                 foreach ( $wgRestrictionLevels as $level ) {
2518                                         if ( in_array( $level, $r ) && $level != '' ) {
2519                                                 return true;
2520                                         }
2521                                 }
2522                         }
2523                 }
2524
2525                 return false;
2526         }
2527
2528         /**
2529          * Determines if $user is unable to edit this page because it has been protected
2530          * by $wgNamespaceProtection.
2531          *
2532          * @param $user User object to check permissions
2533          * @return Bool
2534          */
2535         public function isNamespaceProtected( User $user ) {
2536                 global $wgNamespaceProtection;
2537
2538                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2539                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2540                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2541                                         return true;
2542                                 }
2543                         }
2544                 }
2545                 return false;
2546         }
2547
2548         /**
2549          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2550          *
2551          * @return Bool If the page is subject to cascading restrictions.
2552          */
2553         public function isCascadeProtected() {
2554                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2555                 return ( $sources > 0 );
2556         }
2557
2558         /**
2559          * Cascading protection: Get the source of any cascading restrictions on this page.
2560          *
2561          * @param bool $getPages Whether or not to retrieve the actual pages
2562          *        that the restrictions have come from.
2563          * @return Mixed Array of Title objects of the pages from which cascading restrictions
2564          *     have come, false for none, or true if such restrictions exist, but $getPages
2565          *     was not set.  The restriction array is an array of each type, each of which
2566          *     contains a array of unique groups.
2567          */
2568         public function getCascadeProtectionSources( $getPages = true ) {
2569                 global $wgContLang;
2570                 $pagerestrictions = array();
2571
2572                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2573                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2574                 } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2575                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2576                 }
2577
2578                 wfProfileIn( __METHOD__ );
2579
2580                 $dbr = wfGetDB( DB_SLAVE );
2581
2582                 if ( $this->getNamespace() == NS_FILE ) {
2583                         $tables = array( 'imagelinks', 'page_restrictions' );
2584                         $where_clauses = array(
2585                                 'il_to' => $this->getDBkey(),
2586                                 'il_from=pr_page',
2587                                 'pr_cascade' => 1
2588                         );
2589                 } else {
2590                         $tables = array( 'templatelinks', 'page_restrictions' );
2591                         $where_clauses = array(
2592                                 'tl_namespace' => $this->getNamespace(),
2593                                 'tl_title' => $this->getDBkey(),
2594                                 'tl_from=pr_page',
2595                                 'pr_cascade' => 1
2596                         );
2597                 }
2598
2599                 if ( $getPages ) {
2600                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2601                                 'pr_expiry', 'pr_type', 'pr_level' );
2602                         $where_clauses[] = 'page_id=pr_page';
2603                         $tables[] = 'page';
2604                 } else {
2605                         $cols = array( 'pr_expiry' );
2606                 }
2607
2608                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2609
2610                 $sources = $getPages ? array() : false;
2611                 $now = wfTimestampNow();
2612                 $purgeExpired = false;
2613
2614                 foreach ( $res as $row ) {
2615                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2616                         if ( $expiry > $now ) {
2617                                 if ( $getPages ) {
2618                                         $page_id = $row->pr_page;
2619                                         $page_ns = $row->page_namespace;
2620                                         $page_title = $row->page_title;
2621                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2622                                         # Add groups needed for each restriction type if its not already there
2623                                         # Make sure this restriction type still exists
2624
2625                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2626                                                 $pagerestrictions[$row->pr_type] = array();
2627                                         }
2628
2629                                         if (
2630                                                 isset( $pagerestrictions[$row->pr_type] )
2631                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2632                                         ) {
2633                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2634                                         }
2635                                 } else {
2636                                         $sources = true;
2637                                 }
2638                         } else {
2639                                 // Trigger lazy purge of expired restrictions from the db
2640                                 $purgeExpired = true;
2641                         }
2642                 }
2643                 if ( $purgeExpired ) {
2644                         Title::purgeExpiredRestrictions();
2645                 }
2646
2647                 if ( $getPages ) {
2648                         $this->mCascadeSources = $sources;
2649                         $this->mCascadingRestrictions = $pagerestrictions;
2650                 } else {
2651                         $this->mHasCascadingRestrictions = $sources;
2652                 }
2653
2654                 wfProfileOut( __METHOD__ );
2655                 return array( $sources, $pagerestrictions );
2656         }
2657
2658         /**
2659          * Accessor for mRestrictionsLoaded
2660          *
2661          * @return bool Whether or not the page's restrictions have already been
2662          * loaded from the database
2663          * @since 1.23
2664          */
2665         public function areRestrictionsLoaded() {
2666                 return $this->mRestrictionsLoaded;
2667         }
2668
2669         /**
2670          * Accessor/initialisation for mRestrictions
2671          *
2672          * @param string $action action that permission needs to be checked for
2673          * @return Array of Strings the array of groups allowed to edit this article
2674          */
2675         public function getRestrictions( $action ) {
2676                 if ( !$this->mRestrictionsLoaded ) {
2677                         $this->loadRestrictions();
2678                 }
2679                 return isset( $this->mRestrictions[$action] )
2680                                 ? $this->mRestrictions[$action]
2681                                 : array();
2682         }
2683
2684         /**
2685          * Accessor/initialisation for mRestrictions
2686          *
2687          * @return Array of Arrays of Strings the first level indexed by
2688          * action, the second level containing the names of the groups
2689          * allowed to perform each action
2690          * @since 1.23
2691          */
2692         public function getAllRestrictions() {
2693                 if ( !$this->mRestrictionsLoaded ) {
2694                         $this->loadRestrictions();
2695                 }
2696                 return $this->mRestrictions;
2697         }
2698
2699         /**
2700          * Get the expiry time for the restriction against a given action
2701          *
2702          * @param $action
2703          * @return String|Bool 14-char timestamp, or 'infinity' if the page is protected forever
2704          *     or not protected at all, or false if the action is not recognised.
2705          */
2706         public function getRestrictionExpiry( $action ) {
2707                 if ( !$this->mRestrictionsLoaded ) {
2708                         $this->loadRestrictions();
2709                 }
2710                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2711         }
2712
2713         /**
2714          * Returns cascading restrictions for the current article
2715          *
2716          * @return Boolean
2717          */
2718         function areRestrictionsCascading() {
2719                 if ( !$this->mRestrictionsLoaded ) {
2720                         $this->loadRestrictions();
2721                 }
2722
2723                 return $this->mCascadeRestriction;
2724         }
2725
2726         /**
2727          * Loads a string into mRestrictions array
2728          *
2729          * @param $res Resource restrictions as an SQL result.
2730          * @param string $oldFashionedRestrictions comma-separated list of page
2731          *        restrictions from page table (pre 1.10)
2732          */
2733         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2734                 $rows = array();
2735
2736                 foreach ( $res as $row ) {
2737                         $rows[] = $row;
2738                 }
2739
2740                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2741         }
2742
2743         /**
2744          * Compiles list of active page restrictions from both page table (pre 1.10)
2745          * and page_restrictions table for this existing page.
2746          * Public for usage by LiquidThreads.
2747          *
2748          * @param array $rows of db result objects
2749          * @param string $oldFashionedRestrictions comma-separated list of page
2750          *        restrictions from page table (pre 1.10)
2751          */
2752         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2753                 global $wgContLang;
2754                 $dbr = wfGetDB( DB_SLAVE );
2755
2756                 $restrictionTypes = $this->getRestrictionTypes();
2757
2758                 foreach ( $restrictionTypes as $type ) {
2759                         $this->mRestrictions[$type] = array();
2760                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2761                 }
2762
2763                 $this->mCascadeRestriction = false;
2764
2765                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2766
2767                 if ( $oldFashionedRestrictions === null ) {
2768                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2769                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2770                 }
2771
2772                 if ( $oldFashionedRestrictions != '' ) {
2773
2774                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2775                                 $temp = explode( '=', trim( $restrict ) );
2776                                 if ( count( $temp ) == 1 ) {
2777                                         // old old format should be treated as edit/move restriction
2778                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2779                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2780                                 } else {
2781                                         $restriction = trim( $temp[1] );
2782                                         if ( $restriction != '' ) { //some old entries are empty
2783                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2784                                         }
2785                                 }
2786                         }
2787
2788                         $this->mOldRestrictions = true;
2789
2790                 }
2791
2792                 if ( count( $rows ) ) {
2793                         # Current system - load second to make them override.
2794                         $now = wfTimestampNow();
2795                         $purgeExpired = false;
2796
2797                         # Cycle through all the restrictions.
2798                         foreach ( $rows as $row ) {
2799
2800                                 // Don't take care of restrictions types that aren't allowed
2801                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2802                                         continue;
2803                                 }
2804
2805                                 // This code should be refactored, now that it's being used more generally,
2806                                 // But I don't really see any harm in leaving it in Block for now -werdna
2807                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2808
2809                                 // Only apply the restrictions if they haven't expired!
2810                                 if ( !$expiry || $expiry > $now ) {
2811                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2812                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2813
2814                                         $this->mCascadeRestriction |= $row->pr_cascade;
2815                                 } else {
2816                                         // Trigger a lazy purge of expired restrictions
2817                                         $purgeExpired = true;
2818                                 }
2819                         }
2820
2821                         if ( $purgeExpired ) {
2822                                 Title::purgeExpiredRestrictions();
2823                         }
2824                 }
2825
2826                 $this->mRestrictionsLoaded = true;
2827         }
2828
2829         /**
2830          * Load restrictions from the page_restrictions table
2831          *
2832          * @param string $oldFashionedRestrictions comma-separated list of page
2833          *        restrictions from page table (pre 1.10)
2834          */
2835         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2836                 global $wgContLang;
2837                 if ( !$this->mRestrictionsLoaded ) {
2838                         if ( $this->exists() ) {
2839                                 $dbr = wfGetDB( DB_SLAVE );
2840
2841                                 $res = $dbr->select(
2842                                         'page_restrictions',
2843                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2844                                         array( 'pr_page' => $this->getArticleID() ),
2845                                         __METHOD__
2846                                 );
2847
2848                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2849                         } else {
2850                                 $title_protection = $this->getTitleProtection();
2851
2852                                 if ( $title_protection ) {
2853                                         $now = wfTimestampNow();
2854                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2855
2856                                         if ( !$expiry || $expiry > $now ) {
2857                                                 // Apply the restrictions
2858                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2859                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2860                                         } else { // Get rid of the old restrictions
2861                                                 Title::purgeExpiredRestrictions();
2862                                                 $this->mTitleProtection = false;
2863                                         }
2864                                 } else {
2865                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2866                                 }
2867                                 $this->mRestrictionsLoaded = true;
2868                         }
2869                 }
2870         }
2871
2872         /**
2873          * Flush the protection cache in this object and force reload from the database.
2874          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2875          */
2876         public function flushRestrictions() {
2877                 $this->mRestrictionsLoaded = false;
2878                 $this->mTitleProtection = null;
2879         }
2880
2881         /**
2882          * Purge expired restrictions from the page_restrictions table
2883          */
2884         static function purgeExpiredRestrictions() {
2885                 if ( wfReadOnly() ) {
2886                         return;
2887                 }
2888
2889                 $method = __METHOD__;
2890                 $dbw = wfGetDB( DB_MASTER );
2891                 $dbw->onTransactionIdle( function() use ( $dbw, $method ) {
2892                         $dbw->delete(
2893                                 'page_restrictions',
2894                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2895                                 $method
2896                         );
2897                         $dbw->delete(
2898                                 'protected_titles',
2899                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2900                                 $method
2901                         );
2902                 } );
2903         }
2904
2905         /**
2906          * Does this have subpages?  (Warning, usually requires an extra DB query.)
2907          *
2908          * @return Bool
2909          */
2910         public function hasSubpages() {
2911                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
2912                         # Duh
2913                         return false;
2914                 }
2915
2916                 # We dynamically add a member variable for the purpose of this method
2917                 # alone to cache the result.  There's no point in having it hanging
2918                 # around uninitialized in every Title object; therefore we only add it
2919                 # if needed and don't declare it statically.
2920                 if ( !isset( $this->mHasSubpages ) ) {
2921                         $this->mHasSubpages = false;
2922                         $subpages = $this->getSubpages( 1 );
2923                         if ( $subpages instanceof TitleArray ) {
2924                                 $this->mHasSubpages = (bool)$subpages->count();
2925                         }
2926                 }
2927
2928                 return $this->mHasSubpages;
2929         }
2930
2931         /**
2932          * Get all subpages of this page.
2933          *
2934          * @param int $limit maximum number of subpages to fetch; -1 for no limit
2935          * @return mixed TitleArray, or empty array if this page's namespace
2936          *  doesn't allow subpages
2937          */
2938         public function getSubpages( $limit = -1 ) {
2939                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
2940                         return array();
2941                 }
2942
2943                 $dbr = wfGetDB( DB_SLAVE );
2944                 $conds['page_namespace'] = $this->getNamespace();
2945                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
2946                 $options = array();
2947                 if ( $limit > -1 ) {
2948                         $options['LIMIT'] = $limit;
2949                 }
2950                 $this->mSubpages = TitleArray::newFromResult(
2951                         $dbr->select( 'page',
2952                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
2953                                 $conds,
2954                                 __METHOD__,
2955                                 $options
2956                         )
2957                 );
2958                 return $this->mSubpages;
2959         }
2960
2961         /**
2962          * Is there a version of this page in the deletion archive?
2963          *
2964          * @return Int the number of archived revisions
2965          */
2966         public function isDeleted() {
2967                 if ( $this->getNamespace() < 0 ) {
2968                         $n = 0;
2969                 } else {
2970                         $dbr = wfGetDB( DB_SLAVE );
2971
2972                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
2973                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2974                                 __METHOD__
2975                         );
2976                         if ( $this->getNamespace() == NS_FILE ) {
2977                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
2978                                         array( 'fa_name' => $this->getDBkey() ),
2979                                         __METHOD__
2980                                 );
2981                         }
2982                 }
2983                 return (int)$n;
2984         }
2985
2986         /**
2987          * Is there a version of this page in the deletion archive?
2988          *
2989          * @return Boolean
2990          */
2991         public function isDeletedQuick() {
2992                 if ( $this->getNamespace() < 0 ) {
2993                         return false;
2994                 }
2995                 $dbr = wfGetDB( DB_SLAVE );
2996                 $deleted = (bool)$dbr->selectField( 'archive', '1',
2997                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2998                         __METHOD__
2999                 );
3000                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3001                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3002                                 array( 'fa_name' => $this->getDBkey() ),
3003                                 __METHOD__
3004                         );
3005                 }
3006                 return $deleted;
3007         }
3008
3009         /**
3010          * Get the article ID for this Title from the link cache,
3011          * adding it if necessary
3012          *
3013          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select
3014          *  for update
3015          * @return Int the ID
3016          */
3017         public function getArticleID( $flags = 0 ) {
3018                 if ( $this->getNamespace() < 0 ) {
3019                         $this->mArticleID = 0;
3020                         return $this->mArticleID;
3021                 }
3022                 $linkCache = LinkCache::singleton();
3023                 if ( $flags & self::GAID_FOR_UPDATE ) {
3024                         $oldUpdate = $linkCache->forUpdate( true );
3025                         $linkCache->clearLink( $this );
3026                         $this->mArticleID = $linkCache->addLinkObj( $this );
3027                         $linkCache->forUpdate( $oldUpdate );
3028                 } else {
3029                         if ( -1 == $this->mArticleID ) {
3030                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3031                         }
3032                 }
3033                 return $this->mArticleID;
3034         }
3035
3036         /**
3037          * Is this an article that is a redirect page?
3038          * Uses link cache, adding it if necessary
3039          *
3040          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3041          * @return Bool
3042          */
3043         public function isRedirect( $flags = 0 ) {
3044                 if ( !is_null( $this->mRedirect ) ) {
3045                         return $this->mRedirect;
3046                 }
3047                 # Calling getArticleID() loads the field from cache as needed
3048                 if ( !$this->getArticleID( $flags ) ) {
3049                         $this->mRedirect = false;
3050                         return $this->mRedirect;
3051                 }
3052
3053                 $linkCache = LinkCache::singleton();
3054                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3055                 if ( $cached === null ) {
3056                         # Trust LinkCache's state over our own
3057                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3058                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3059                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3060                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3061                         # LinkCache to refresh its data from the master.
3062                         $this->mRedirect = false;
3063                         return $this->mRedirect;
3064                 }
3065
3066                 $this->mRedirect = (bool)$cached;
3067
3068                 return $this->mRedirect;
3069         }
3070
3071         /**
3072          * What is the length of this page?
3073          * Uses link cache, adding it if necessary
3074          *
3075          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3076          * @return Int
3077          */
3078         public function getLength( $flags = 0 ) {
3079                 if ( $this->mLength != -1 ) {
3080                         return $this->mLength;
3081                 }
3082                 # Calling getArticleID() loads the field from cache as needed
3083                 if ( !$this->getArticleID( $flags ) ) {
3084                         $this->mLength = 0;
3085                         return $this->mLength;
3086                 }
3087                 $linkCache = LinkCache::singleton();
3088                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3089                 if ( $cached === null ) {
3090                         # Trust LinkCache's state over our own, as for isRedirect()
3091                         $this->mLength = 0;
3092                         return $this->mLength;
3093                 }
3094
3095                 $this->mLength = intval( $cached );
3096
3097                 return $this->mLength;
3098         }
3099
3100         /**
3101          * What is the page_latest field for this page?
3102          *
3103          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3104          * @return Int or 0 if the page doesn't exist
3105          */
3106         public function getLatestRevID( $flags = 0 ) {
3107                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3108                         return intval( $this->mLatestID );
3109                 }
3110                 # Calling getArticleID() loads the field from cache as needed
3111                 if ( !$this->getArticleID( $flags ) ) {
3112                         $this->mLatestID = 0;
3113                         return $this->mLatestID;
3114                 }
3115                 $linkCache = LinkCache::singleton();
3116                 $linkCache->addLinkObj( $this );
3117                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3118                 if ( $cached === null ) {
3119                         # Trust LinkCache's state over our own, as for isRedirect()
3120                         $this->mLatestID = 0;
3121                         return $this->mLatestID;
3122                 }
3123
3124                 $this->mLatestID = intval( $cached );
3125
3126                 return $this->mLatestID;
3127         }
3128
3129         /**
3130          * This clears some fields in this object, and clears any associated
3131          * keys in the "bad links" section of the link cache.
3132          *
3133          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3134          * loading of the new page_id. It's also called from
3135          * WikiPage::doDeleteArticleReal()
3136          *
3137          * @param int $newid the new Article ID
3138          */
3139         public function resetArticleID( $newid ) {
3140                 $linkCache = LinkCache::singleton();
3141                 $linkCache->clearLink( $this );
3142
3143                 if ( $newid === false ) {
3144                         $this->mArticleID = -1;
3145                 } else {
3146                         $this->mArticleID = intval( $newid );
3147                 }
3148                 $this->mRestrictionsLoaded = false;
3149                 $this->mRestrictions = array();
3150                 $this->mRedirect = null;
3151                 $this->mLength = -1;
3152                 $this->mLatestID = false;
3153                 $this->mContentModel = false;
3154                 $this->mEstimateRevisions = null;
3155                 $this->mPageLanguage = false;
3156         }
3157
3158         /**
3159          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3160          *
3161          * @param string $text containing title to capitalize
3162          * @param int $ns namespace index, defaults to NS_MAIN
3163          * @return String containing capitalized title
3164          */
3165         public static function capitalize( $text, $ns = NS_MAIN ) {
3166                 global $wgContLang;
3167
3168                 if ( MWNamespace::isCapitalized( $ns ) ) {
3169                         return $wgContLang->ucfirst( $text );
3170                 } else {
3171                         return $text;
3172                 }
3173         }
3174
3175         /**
3176          * Secure and split - main initialisation function for this object
3177          *
3178          * Assumes that mDbkeyform has been set, and is urldecoded
3179          * and uses underscores, but not otherwise munged.  This function
3180          * removes illegal characters, splits off the interwiki and
3181          * namespace prefixes, sets the other forms, and canonicalizes
3182          * everything.
3183          *
3184          * @return Bool true on success
3185          */
3186         private function secureAndSplit() {
3187                 global $wgContLang, $wgLocalInterwiki;
3188
3189                 # Initialisation
3190                 $this->mInterwiki = $this->mFragment = '';
3191                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3192
3193                 $dbkey = $this->mDbkeyform;
3194
3195                 # Strip Unicode bidi override characters.
3196                 # Sometimes they slip into cut-n-pasted page titles, where the
3197                 # override chars get included in list displays.
3198                 $dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );
3199
3200                 # Clean up whitespace
3201                 # Note: use of the /u option on preg_replace here will cause
3202                 # input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
3203                 # conveniently disabling them.
3204                 $dbkey = preg_replace( '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u', '_', $dbkey );
3205                 $dbkey = trim( $dbkey, '_' );
3206
3207                 if ( strpos( $dbkey, UTF8_REPLACEMENT ) !== false ) {
3208                         # Contained illegal UTF-8 sequences or forbidden Unicode chars.
3209                         return false;
3210                 }
3211
3212                 $this->mDbkeyform = $dbkey;
3213
3214                 # Initial colon indicates main namespace rather than specified default
3215                 # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
3216                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3217                         $this->mNamespace = NS_MAIN;
3218                         $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
3219                         $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
3220                 }
3221
3222                 if ( $dbkey == '' ) {
3223                         return false;
3224                 }
3225
3226                 # Namespace or interwiki prefix
3227                 $firstPass = true;
3228                 $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
3229                 do {
3230                         $m = array();
3231                         if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
3232                                 $p = $m[1];
3233                                 if ( ( $ns = $wgContLang->getNsIndex( $p ) ) !== false ) {
3234                                         # Ordinary namespace
3235                                         $dbkey = $m[2];
3236                                         $this->mNamespace = $ns;
3237                                         # For Talk:X pages, check if X has a "namespace" prefix
3238                                         if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
3239                                                 if ( $wgContLang->getNsIndex( $x[1] ) ) {
3240                                                         # Disallow Talk:File:x type titles...
3241                                                         return false;
3242                                                 } elseif ( Interwiki::isValidInterwiki( $x[1] ) ) {
3243                                                         # Disallow Talk:Interwiki:x type titles...
3244                                                         return false;
3245                                                 }
3246                                         }
3247                                 } elseif ( Interwiki::isValidInterwiki( $p ) ) {
3248                                         if ( !$firstPass ) {
3249                                                 # Can't make a local interwiki link to an interwiki link.
3250                                                 # That's just crazy!
3251                                                 return false;
3252                                         }
3253
3254                                         # Interwiki link
3255                                         $dbkey = $m[2];
3256                                         $this->mInterwiki = $wgContLang->lc( $p );
3257
3258                                         # Redundant interwiki prefix to the local wiki
3259                                         if ( $wgLocalInterwiki !== false
3260                                                 && 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki )
3261                                         ) {
3262                                                 if ( $dbkey == '' ) {
3263                                                         # Can't have an empty self-link
3264                                                         return false;
3265                                                 }
3266                                                 $this->mInterwiki = '';
3267                                                 $firstPass = false;
3268                                                 # Do another namespace split...
3269                                                 continue;
3270                                         }
3271
3272                                         # If there's an initial colon after the interwiki, that also
3273                                         # resets the default namespace
3274                                         if ( $dbkey !== '' && $dbkey[0] == ':' ) {
3275                                                 $this->mNamespace = NS_MAIN;
3276                                                 $dbkey = substr( $dbkey, 1 );
3277                                         }
3278                                 }
3279                                 # If there's no recognized interwiki or namespace,
3280                                 # then let the colon expression be part of the title.
3281                         }
3282                         break;
3283                 } while ( true );
3284
3285                 # We already know that some pages won't be in the database!
3286                 if ( $this->isExternal() || NS_SPECIAL == $this->mNamespace ) {
3287                         $this->mArticleID = 0;
3288                 }
3289                 $fragment = strstr( $dbkey, '#' );
3290                 if ( false !== $fragment ) {
3291                         $this->setFragment( $fragment );
3292                         $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
3293                         # remove whitespace again: prevents "Foo_bar_#"
3294                         # becoming "Foo_bar_"
3295                         $dbkey = preg_replace( '/_*$/', '', $dbkey );
3296                 }
3297
3298                 # Reject illegal characters.
3299                 $rxTc = self::getTitleInvalidRegex();
3300                 if ( preg_match( $rxTc, $dbkey ) ) {
3301                         return false;
3302                 }
3303
3304                 # Pages with "/./" or "/../" appearing in the URLs will often be un-
3305                 # reachable due to the way web browsers deal with 'relative' URLs.
3306                 # Also, they conflict with subpage syntax.  Forbid them explicitly.
3307                 if (
3308                         strpos( $dbkey, '.' ) !== false &&
3309                         (
3310                                 $dbkey === '.' || $dbkey === '..' ||
3311                                 strpos( $dbkey, './' ) === 0 ||
3312                                 strpos( $dbkey, '../' ) === 0 ||
3313                                 strpos( $dbkey, '/./' ) !== false ||
3314                                 strpos( $dbkey, '/../' ) !== false ||
3315                                 substr( $dbkey, -2 ) == '/.' ||
3316                                 substr( $dbkey, -3 ) == '/..'
3317                         )
3318                 ) {
3319                         return false;
3320                 }
3321
3322                 # Magic tilde sequences? Nu-uh!
3323                 if ( strpos( $dbkey, '~~~' ) !== false ) {
3324                         return false;
3325                 }
3326
3327                 # Limit the size of titles to 255 bytes. This is typically the size of the
3328                 # underlying database field. We make an exception for special pages, which
3329                 # don't need to be stored in the database, and may edge over 255 bytes due
3330                 # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
3331                 if (
3332                         ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 )
3333                         || strlen( $dbkey ) > 512
3334                 ) {
3335                         return false;
3336                 }
3337
3338                 # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
3339                 # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
3340                 # other site might be case-sensitive.
3341                 $this->mUserCaseDBKey = $dbkey;
3342                 if ( !$this->isExternal() ) {
3343                         $dbkey = self::capitalize( $dbkey, $this->mNamespace );
3344                 }
3345
3346                 # Can't make a link to a namespace alone... "empty" local links can only be
3347                 # self-links with a fragment identifier.
3348                 if ( $dbkey == '' && !$this->isExternal() && $this->mNamespace != NS_MAIN ) {
3349                         return false;
3350                 }
3351
3352                 // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
3353                 // IP names are not allowed for accounts, and can only be referring to
3354                 // edits from the IP. Given '::' abbreviations and caps/lowercaps,
3355                 // there are numerous ways to present the same IP. Having sp:contribs scan
3356                 // them all is silly and having some show the edits and others not is
3357                 // inconsistent. Same for talk/userpages. Keep them normalized instead.
3358                 $dbkey = ( $this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK )
3359                         ? IP::sanitizeIP( $dbkey )
3360                         : $dbkey;
3361
3362                 // Any remaining initial :s are illegal.
3363                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3364                         return false;
3365                 }
3366
3367                 # Fill fields
3368                 $this->mDbkeyform = $dbkey;
3369                 $this->mUrlform = wfUrlencode( $dbkey );
3370
3371                 $this->mTextform = str_replace( '_', ' ', $dbkey );
3372
3373                 return true;
3374         }
3375
3376         /**
3377          * Get an array of Title objects linking to this Title
3378          * Also stores the IDs in the link cache.
3379          *
3380          * WARNING: do not use this function on arbitrary user-supplied titles!
3381          * On heavily-used templates it will max out the memory.
3382          *
3383          * @param array $options may be FOR UPDATE
3384          * @param string $table table name
3385          * @param string $prefix fields prefix
3386          * @return Array of Title objects linking here
3387          */
3388         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3389                 if ( count( $options ) > 0 ) {
3390                         $db = wfGetDB( DB_MASTER );
3391                 } else {
3392                         $db = wfGetDB( DB_SLAVE );
3393                 }
3394
3395                 $res = $db->select(
3396                         array( 'page', $table ),
3397                         self::getSelectFields(),
3398                         array(
3399                                 "{$prefix}_from=page_id",
3400                                 "{$prefix}_namespace" => $this->getNamespace(),
3401                                 "{$prefix}_title" => $this->getDBkey() ),
3402                         __METHOD__,
3403                         $options
3404                 );
3405
3406                 $retVal = array();
3407                 if ( $res->numRows() ) {
3408                         $linkCache = LinkCache::singleton();
3409                         foreach ( $res as $row ) {
3410                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3411                                 if ( $titleObj ) {
3412                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3413                                         $retVal[] = $titleObj;
3414                                 }
3415                         }
3416                 }
3417                 return $retVal;
3418         }
3419
3420         /**
3421          * Get an array of Title objects using this Title as a template
3422          * Also stores the IDs in the link cache.
3423          *
3424          * WARNING: do not use this function on arbitrary user-supplied titles!
3425          * On heavily-used templates it will max out the memory.
3426          *
3427          * @param array $options may be FOR UPDATE
3428          * @return Array of Title the Title objects linking here
3429          */
3430         public function getTemplateLinksTo( $options = array() ) {
3431                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3432         }
3433
3434         /**
3435          * Get an array of Title objects linked from this Title
3436          * Also stores the IDs in the link cache.
3437          *
3438          * WARNING: do not use this function on arbitrary user-supplied titles!
3439          * On heavily-used templates it will max out the memory.
3440          *
3441          * @param array $options may be FOR UPDATE
3442          * @param string $table table name
3443          * @param string $prefix fields prefix
3444          * @return Array of Title objects linking here
3445          */
3446         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3447                 global $wgContentHandlerUseDB;
3448
3449                 $id = $this->getArticleID();
3450
3451                 # If the page doesn't exist; there can't be any link from this page
3452                 if ( !$id ) {
3453                         return array();
3454                 }
3455
3456                 if ( count( $options ) > 0 ) {
3457                         $db = wfGetDB( DB_MASTER );
3458                 } else {
3459                         $db = wfGetDB( DB_SLAVE );
3460                 }
3461
3462                 $namespaceFiled = "{$prefix}_namespace";
3463                 $titleField = "{$prefix}_title";
3464
3465                 $fields = array( $namespaceFiled, $titleField, 'page_id', 'page_len', 'page_is_redirect', 'page_latest' );
3466                 if ( $wgContentHandlerUseDB ) {
3467                         $fields[] = 'page_content_model';
3468                 }
3469
3470                 $res = $db->select(
3471                         array( $table, 'page' ),
3472                         $fields,
3473                         array( "{$prefix}_from" => $id ),
3474                         __METHOD__,
3475                         $options,
3476                         array( 'page' => array( 'LEFT JOIN', array( "page_namespace=$namespaceFiled", "page_title=$titleField" ) ) )
3477                 );
3478
3479                 $retVal = array();
3480                 if ( $res->numRows() ) {
3481                         $linkCache = LinkCache::singleton();
3482                         foreach ( $res as $row ) {
3483                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3484                                 if ( $titleObj ) {
3485                                         if ( $row->page_id ) {
3486                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3487                                         } else {
3488                                                 $linkCache->addBadLinkObj( $titleObj );
3489                                         }
3490                                         $retVal[] = $titleObj;
3491                                 }
3492                         }
3493                 }
3494                 return $retVal;
3495         }
3496
3497         /**
3498          * Get an array of Title objects used on this Title as a template
3499          * Also stores the IDs in the link cache.
3500          *
3501          * WARNING: do not use this function on arbitrary user-supplied titles!
3502          * On heavily-used templates it will max out the memory.
3503          *
3504          * @param array $options may be FOR UPDATE
3505          * @return Array of Title the Title objects used here
3506          */
3507         public function getTemplateLinksFrom( $options = array() ) {
3508                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3509         }
3510
3511         /**
3512          * Get an array of Title objects referring to non-existent articles linked from this page
3513          *
3514          * @todo check if needed (used only in SpecialBrokenRedirects.php, and should use redirect table in this case)
3515          * @return Array of Title the Title objects
3516          */
3517         public function getBrokenLinksFrom() {
3518                 if ( $this->getArticleID() == 0 ) {
3519                         # All links from article ID 0 are false positives
3520                         return array();
3521                 }
3522
3523                 $dbr = wfGetDB( DB_SLAVE );
3524                 $res = $dbr->select(
3525                         array( 'page', 'pagelinks' ),
3526                         array( 'pl_namespace', 'pl_title' ),
3527                         array(
3528                                 'pl_from' => $this->getArticleID(),
3529                                 'page_namespace IS NULL'
3530                         ),
3531                         __METHOD__, array(),
3532                         array(
3533                                 'page' => array(
3534                                         'LEFT JOIN',
3535                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3536                                 )
3537                         )
3538                 );
3539
3540                 $retVal = array();
3541                 foreach ( $res as $row ) {
3542                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3543                 }
3544                 return $retVal;
3545         }
3546
3547         /**
3548          * Get a list of URLs to purge from the Squid cache when this
3549          * page changes
3550          *
3551          * @return Array of String the URLs
3552          */
3553         public function getSquidURLs() {
3554                 $urls = array(
3555                         $this->getInternalURL(),
3556                         $this->getInternalURL( 'action=history' )
3557                 );
3558
3559                 $pageLang = $this->getPageLanguage();
3560                 if ( $pageLang->hasVariants() ) {
3561                         $variants = $pageLang->getVariants();
3562                         foreach ( $variants as $vCode ) {
3563                                 $urls[] = $this->getInternalURL( '', $vCode );
3564                         }
3565                 }
3566
3567                 // If we are looking at a css/js user subpage, purge the action=raw.
3568                 if ( $this->isJsSubpage() ) {
3569                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3570                 } elseif ( $this->isCssSubpage() ) {
3571                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3572                 }
3573
3574                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3575                 return $urls;
3576         }
3577
3578         /**
3579          * Purge all applicable Squid URLs
3580          */
3581         public function purgeSquid() {
3582                 global $wgUseSquid;
3583                 if ( $wgUseSquid ) {
3584                         $urls = $this->getSquidURLs();
3585                         $u = new SquidUpdate( $urls );
3586                         $u->doUpdate();
3587                 }
3588         }
3589
3590         /**
3591          * Move this page without authentication
3592          *
3593          * @param $nt Title the new page Title
3594          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3595          */
3596         public function moveNoAuth( &$nt ) {
3597                 return $this->moveTo( $nt, false );
3598         }
3599
3600         /**
3601          * Check whether a given move operation would be valid.
3602          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3603          *
3604          * @param $nt Title the new title
3605          * @param bool $auth indicates whether $wgUser's permissions
3606          *  should be checked
3607          * @param string $reason is the log summary of the move, used for spam checking
3608          * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
3609          */
3610         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3611                 global $wgUser, $wgContentHandlerUseDB;
3612
3613                 $errors = array();
3614                 if ( !$nt ) {
3615                         // Normally we'd add this to $errors, but we'll get
3616                         // lots of syntax errors if $nt is not an object
3617                         return array( array( 'badtitletext' ) );
3618                 }
3619                 if ( $this->equals( $nt ) ) {
3620                         $errors[] = array( 'selfmove' );
3621                 }
3622                 if ( !$this->isMovable() ) {
3623                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3624                 }
3625                 if ( $nt->isExternal() ) {
3626                         $errors[] = array( 'immobile-target-namespace-iw' );
3627                 }
3628                 if ( !$nt->isMovable() ) {
3629                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3630                 }
3631
3632                 $oldid = $this->getArticleID();
3633                 $newid = $nt->getArticleID();
3634
3635                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3636                         $errors[] = array( 'articleexists' );
3637                 }
3638                 if (
3639                         ( $this->getDBkey() == '' ) ||
3640                         ( !$oldid ) ||
3641                         ( $nt->getDBkey() == '' )
3642                 ) {
3643                         $errors[] = array( 'badarticleerror' );
3644                 }
3645
3646                 // Content model checks
3647                 if ( !$wgContentHandlerUseDB &&
3648                                 $this->getContentModel() !== $nt->getContentModel() ) {
3649                         // can't move a page if that would change the page's content model
3650                         $errors[] = array(
3651                                 'bad-target-model',
3652                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3653                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3654                         );
3655                 }
3656
3657                 // Image-specific checks
3658                 if ( $this->getNamespace() == NS_FILE ) {
3659                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3660                 }
3661
3662                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3663                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3664                 }
3665
3666                 if ( $auth ) {
3667                         $errors = wfMergeErrorArrays( $errors,
3668                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3669                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3670                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3671                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3672                 }
3673
3674                 $match = EditPage::matchSummarySpamRegex( $reason );
3675                 if ( $match !== false ) {
3676                         // This is kind of lame, won't display nice
3677                         $errors[] = array( 'spamprotectiontext' );
3678                 }
3679
3680                 $err = null;
3681                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3682                         $errors[] = array( 'hookaborted', $err );
3683                 }
3684
3685                 # The move is allowed only if (1) the target doesn't exist, or
3686                 # (2) the target is a redirect to the source, and has no history
3687                 # (so we can undo bad moves right after they're done).
3688
3689                 if ( 0 != $newid ) { # Target exists; check for validity
3690                         if ( !$this->isValidMoveTarget( $nt ) ) {
3691                                 $errors[] = array( 'articleexists' );
3692                         }
3693                 } else {
3694                         $tp = $nt->getTitleProtection();
3695                         $right = $tp['pt_create_perm'];
3696                         if ( $right == 'sysop' ) {
3697                                 $right = 'editprotected'; // B/C
3698                         }
3699                         if ( $right == 'autoconfirmed' ) {
3700                                 $right = 'editsemiprotected'; // B/C
3701                         }
3702                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3703                                 $errors[] = array( 'cantmove-titleprotected' );
3704                         }
3705                 }
3706                 if ( empty( $errors ) ) {
3707                         return true;
3708                 }
3709                 return $errors;
3710         }
3711
3712         /**
3713          * Check if the requested move target is a valid file move target
3714          * @param Title $nt Target title
3715          * @return array List of errors
3716          */
3717         protected function validateFileMoveOperation( $nt ) {
3718                 global $wgUser;
3719
3720                 $errors = array();
3721
3722                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3723
3724                 $file = wfLocalFile( $this );
3725                 if ( $file->exists() ) {
3726                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3727                                 $errors[] = array( 'imageinvalidfilename' );
3728                         }
3729                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3730                                 $errors[] = array( 'imagetypemismatch' );
3731                         }
3732                 }
3733
3734                 if ( $nt->getNamespace() != NS_FILE ) {
3735                         $errors[] = array( 'imagenocrossnamespace' );
3736                         // From here we want to do checks on a file object, so if we can't
3737                         // create one, we must return.
3738                         return $errors;
3739                 }
3740
3741                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3742
3743                 $destFile = wfLocalFile( $nt );
3744                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3745                         $errors[] = array( 'file-exists-sharedrepo' );
3746                 }
3747
3748                 return $errors;
3749         }
3750
3751         /**
3752          * Move a title to a new location
3753          *
3754          * @param $nt Title the new title
3755          * @param bool $auth indicates whether $wgUser's permissions
3756          *  should be checked
3757          * @param string $reason the reason for the move
3758          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3759          *  Ignored if the user doesn't have the suppressredirect right.
3760          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3761          */
3762         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3763                 global $wgUser;
3764                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3765                 if ( is_array( $err ) ) {
3766                         // Auto-block user's IP if the account was "hard" blocked
3767                         $wgUser->spreadAnyEditBlock();
3768                         return $err;
3769                 }
3770                 // Check suppressredirect permission
3771                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3772                         $createRedirect = true;
3773                 }
3774
3775                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3776
3777                 // If it is a file, move it first.
3778                 // It is done before all other moving stuff is done because it's hard to revert.
3779                 $dbw = wfGetDB( DB_MASTER );
3780                 if ( $this->getNamespace() == NS_FILE ) {
3781                         $file = wfLocalFile( $this );
3782                         if ( $file->exists() ) {
3783                                 $status = $file->move( $nt );
3784                                 if ( !$status->isOk() ) {
3785                                         return $status->getErrorsArray();
3786                                 }
3787                         }
3788                         // Clear RepoGroup process cache
3789                         RepoGroup::singleton()->clearCache( $this );
3790                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3791                 }
3792
3793                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3794                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3795                 $protected = $this->isProtected();
3796
3797                 // Do the actual move
3798                 $this->moveToInternal( $nt, $reason, $createRedirect );
3799
3800                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3801                 // cl_timestamp, which may disturb time-based lists on some sites.
3802                 $prefixes = $dbw->select(
3803                         'categorylinks',
3804                         array( 'cl_sortkey_prefix', 'cl_to' ),
3805                         array( 'cl_from' => $pageid ),
3806                         __METHOD__
3807                 );
3808                 foreach ( $prefixes as $prefixRow ) {
3809                         $prefix = $prefixRow->cl_sortkey_prefix;
3810                         $catTo = $prefixRow->cl_to;
3811                         $dbw->update( 'categorylinks',
3812                                 array(
3813                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3814                                                 $nt->getCategorySortkey( $prefix ) ),
3815                                         'cl_timestamp=cl_timestamp' ),
3816                                 array(
3817                                         'cl_from' => $pageid,
3818                                         'cl_to' => $catTo ),
3819                                 __METHOD__
3820                         );
3821                 }
3822
3823                 $redirid = $this->getArticleID();
3824
3825                 if ( $protected ) {
3826                         # Protect the redirect title as the title used to be...
3827                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3828                                 array(
3829                                         'pr_page' => $redirid,
3830                                         'pr_type' => 'pr_type',
3831                                         'pr_level' => 'pr_level',
3832                                         'pr_cascade' => 'pr_cascade',
3833                                         'pr_user' => 'pr_user',
3834                                         'pr_expiry' => 'pr_expiry'
3835                                 ),
3836                                 array( 'pr_page' => $pageid ),
3837                                 __METHOD__,
3838                                 array( 'IGNORE' )
3839                         );
3840                         # Update the protection log
3841                         $log = new LogPage( 'protect' );
3842                         $comment = wfMessage(
3843                                 'prot_1movedto2',
3844                                 $this->getPrefixedText(),
3845                                 $nt->getPrefixedText()
3846                         )->inContentLanguage()->text();
3847                         if ( $reason ) {
3848                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3849                         }
3850                         // @todo FIXME: $params?
3851                         $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ), $wgUser );
3852                 }
3853
3854                 # Update watchlists
3855                 $oldnamespace = MWNamespace::getSubject( $this->getNamespace() );
3856                 $newnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3857                 $oldtitle = $this->getDBkey();
3858                 $newtitle = $nt->getDBkey();
3859
3860                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3861                         WatchedItem::duplicateEntries( $this, $nt );
3862                 }
3863
3864                 $dbw->commit( __METHOD__ );
3865
3866                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
3867                 return true;
3868         }
3869
3870         /**
3871          * Move page to a title which is either a redirect to the
3872          * source page or nonexistent
3873          *
3874          * @param $nt Title the page to move to, which should be a redirect or nonexistent
3875          * @param string $reason The reason for the move
3876          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3877          *   if the user has the suppressredirect right
3878          * @throws MWException
3879          */
3880         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3881                 global $wgUser, $wgContLang;
3882
3883                 if ( $nt->exists() ) {
3884                         $moveOverRedirect = true;
3885                         $logType = 'move_redir';
3886                 } else {
3887                         $moveOverRedirect = false;
3888                         $logType = 'move';
3889                 }
3890
3891                 if ( $createRedirect ) {
3892                         $contentHandler = ContentHandler::getForTitle( $this );
3893                         $redirectContent = $contentHandler->makeRedirectContent( $nt,
3894                                 wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3895
3896                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3897                 } else {
3898                         $redirectContent = null;
3899                 }
3900
3901                 $logEntry = new ManualLogEntry( 'move', $logType );
3902                 $logEntry->setPerformer( $wgUser );
3903                 $logEntry->setTarget( $this );
3904                 $logEntry->setComment( $reason );
3905                 $logEntry->setParameters( array(
3906                         '4::target' => $nt->getPrefixedText(),
3907                         '5::noredir' => $redirectContent ? '0': '1',
3908                 ) );
3909
3910                 $formatter = LogFormatter::newFromEntry( $logEntry );
3911                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3912                 $comment = $formatter->getPlainActionText();
3913                 if ( $reason ) {
3914                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3915                 }
3916                 # Truncate for whole multibyte characters.
3917                 $comment = $wgContLang->truncate( $comment, 255 );
3918
3919                 $oldid = $this->getArticleID();
3920
3921                 $dbw = wfGetDB( DB_MASTER );
3922
3923                 $newpage = WikiPage::factory( $nt );
3924
3925                 if ( $moveOverRedirect ) {
3926                         $newid = $nt->getArticleID();
3927                         $newcontent = $newpage->getContent();
3928
3929                         # Delete the old redirect. We don't save it to history since
3930                         # by definition if we've got here it's rather uninteresting.
3931                         # We have to remove it so that the next step doesn't trigger
3932                         # a conflict on the unique namespace+title index...
3933                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3934
3935                         $newpage->doDeleteUpdates( $newid, $newcontent );
3936                 }
3937
3938                 # Save a null revision in the page's history notifying of the move
3939                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
3940                 if ( !is_object( $nullRevision ) ) {
3941                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3942                 }
3943
3944                 $nullRevision->insertOn( $dbw );
3945
3946                 # Change the name of the target page:
3947                 $dbw->update( 'page',
3948                         /* SET */ array(
3949                                 'page_namespace' => $nt->getNamespace(),
3950                                 'page_title' => $nt->getDBkey(),
3951                         ),
3952                         /* WHERE */ array( 'page_id' => $oldid ),
3953                         __METHOD__
3954                 );
3955
3956                 // clean up the old title before reset article id - bug 45348
3957                 if ( !$redirectContent ) {
3958                         WikiPage::onArticleDelete( $this );
3959                 }
3960
3961                 $this->resetArticleID( 0 ); // 0 == non existing
3962                 $nt->resetArticleID( $oldid );
3963                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
3964
3965                 $newpage->updateRevisionOn( $dbw, $nullRevision );
3966
3967                 wfRunHooks( 'NewRevisionFromEditComplete',
3968                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
3969
3970                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
3971
3972                 if ( !$moveOverRedirect ) {
3973                         WikiPage::onArticleCreate( $nt );
3974                 }
3975
3976                 # Recreate the redirect, this time in the other direction.
3977                 if ( $redirectContent ) {
3978                         $redirectArticle = WikiPage::factory( $this );
3979                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
3980                         $newid = $redirectArticle->insertOn( $dbw );
3981                         if ( $newid ) { // sanity
3982                                 $this->resetArticleID( $newid );
3983                                 $redirectRevision = new Revision( array(
3984                                         'title' => $this, // for determining the default content model
3985                                         'page' => $newid,
3986                                         'comment' => $comment,
3987                                         'content' => $redirectContent ) );
3988                                 $redirectRevision->insertOn( $dbw );
3989                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
3990
3991                                 wfRunHooks( 'NewRevisionFromEditComplete',
3992                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
3993
3994                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
3995                         }
3996                 }
3997
3998                 # Log the move
3999                 $logid = $logEntry->insert();
4000                 $logEntry->publish( $logid );
4001         }
4002
4003         /**
4004          * Move this page's subpages to be subpages of $nt
4005          *
4006          * @param $nt Title Move target
4007          * @param bool $auth Whether $wgUser's permissions should be checked
4008          * @param string $reason The reason for the move
4009          * @param bool $createRedirect Whether to create redirects from the old subpages to
4010          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4011          * @return mixed array with old page titles as keys, and strings (new page titles) or
4012          *     arrays (errors) as values, or an error array with numeric indices if no pages
4013          *     were moved
4014          */
4015         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
4016                 global $wgMaximumMovedPages;
4017                 // Check permissions
4018                 if ( !$this->userCan( 'move-subpages' ) ) {
4019                         return array( 'cant-move-subpages' );
4020                 }
4021                 // Do the source and target namespaces support subpages?
4022                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4023                         return array( 'namespace-nosubpages',
4024                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
4025                 }
4026                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4027                         return array( 'namespace-nosubpages',
4028                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
4029                 }
4030
4031                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4032                 $retval = array();
4033                 $count = 0;
4034                 foreach ( $subpages as $oldSubpage ) {
4035                         $count++;
4036                         if ( $count > $wgMaximumMovedPages ) {
4037                                 $retval[$oldSubpage->getPrefixedTitle()] =
4038                                                 array( 'movepage-max-pages',
4039                                                         $wgMaximumMovedPages );
4040                                 break;
4041                         }
4042
4043                         // We don't know whether this function was called before
4044                         // or after moving the root page, so check both
4045                         // $this and $nt
4046                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4047                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4048                         ) {
4049                                 // When moving a page to a subpage of itself,
4050                                 // don't move it twice
4051                                 continue;
4052                         }
4053                         $newPageName = preg_replace(
4054                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4055                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4056                                         $oldSubpage->getDBkey() );
4057                         if ( $oldSubpage->isTalkPage() ) {
4058                                 $newNs = $nt->getTalkPage()->getNamespace();
4059                         } else {
4060                                 $newNs = $nt->getSubjectPage()->getNamespace();
4061                         }
4062                         # Bug 14385: we need makeTitleSafe because the new page names may
4063                         # be longer than 255 characters.
4064                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4065
4066                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4067                         if ( $success === true ) {
4068                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4069                         } else {
4070                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4071                         }
4072                 }
4073                 return $retval;
4074         }
4075
4076         /**
4077          * Checks if this page is just a one-rev redirect.
4078          * Adds lock, so don't use just for light purposes.
4079          *
4080          * @return Bool
4081          */
4082         public function isSingleRevRedirect() {
4083                 global $wgContentHandlerUseDB;
4084
4085                 $dbw = wfGetDB( DB_MASTER );
4086
4087                 # Is it a redirect?
4088                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4089                 if ( $wgContentHandlerUseDB ) {
4090                         $fields[] = 'page_content_model';
4091                 }
4092
4093                 $row = $dbw->selectRow( 'page',
4094                         $fields,
4095                         $this->pageCond(),
4096                         __METHOD__,
4097                         array( 'FOR UPDATE' )
4098                 );
4099                 # Cache some fields we may want
4100                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4101                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4102                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4103                 $this->mContentModel = $row && isset( $row->page_content_model ) ? strval( $row->page_content_model ) : false;
4104                 if ( !$this->mRedirect ) {
4105                         return false;
4106                 }
4107                 # Does the article have a history?
4108                 $row = $dbw->selectField( array( 'page', 'revision' ),
4109                         'rev_id',
4110                         array( 'page_namespace' => $this->getNamespace(),
4111                                 'page_title' => $this->getDBkey(),
4112                                 'page_id=rev_page',
4113                                 'page_latest != rev_id'
4114                         ),
4115                         __METHOD__,
4116                         array( 'FOR UPDATE' )
4117                 );
4118                 # Return true if there was no history
4119                 return ( $row === false );
4120         }
4121
4122         /**
4123          * Checks if $this can be moved to a given Title
4124          * - Selects for update, so don't call it unless you mean business
4125          *
4126          * @param $nt Title the new title to check
4127          * @return Bool
4128          */
4129         public function isValidMoveTarget( $nt ) {
4130                 # Is it an existing file?
4131                 if ( $nt->getNamespace() == NS_FILE ) {
4132                         $file = wfLocalFile( $nt );
4133                         if ( $file->exists() ) {
4134                                 wfDebug( __METHOD__ . ": file exists\n" );
4135                                 return false;
4136                         }
4137                 }
4138                 # Is it a redirect with no history?
4139                 if ( !$nt->isSingleRevRedirect() ) {
4140                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4141                         return false;
4142                 }
4143                 # Get the article text
4144                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4145                 if ( !is_object( $rev ) ) {
4146                         return false;
4147                 }
4148                 $content = $rev->getContent();
4149                 # Does the redirect point to the source?
4150                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4151                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4152
4153                 if ( $redirTitle ) {
4154                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4155                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4156                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4157                                 return false;
4158                         } else {
4159                                 return true;
4160                         }
4161                 } else {
4162                         # Fail safe (not a redirect after all. strange.)
4163                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4164                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4165                         return false;
4166                 }
4167         }
4168
4169         /**
4170          * Get categories to which this Title belongs and return an array of
4171          * categories' names.
4172          *
4173          * @return Array of parents in the form:
4174          *        $parent => $currentarticle
4175          */
4176         public function getParentCategories() {
4177                 global $wgContLang;
4178
4179                 $data = array();
4180
4181                 $titleKey = $this->getArticleID();
4182
4183                 if ( $titleKey === 0 ) {
4184                         return $data;
4185                 }
4186
4187                 $dbr = wfGetDB( DB_SLAVE );
4188
4189                 $res = $dbr->select(
4190                         'categorylinks',
4191                         'cl_to',
4192                         array( 'cl_from' => $titleKey ),
4193                         __METHOD__
4194                 );
4195
4196                 if ( $res->numRows() > 0 ) {
4197                         foreach ( $res as $row ) {
4198                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4199                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4200                         }
4201                 }
4202                 return $data;
4203         }
4204
4205         /**
4206          * Get a tree of parent categories
4207          *
4208          * @param array $children with the children in the keys, to check for circular refs
4209          * @return Array Tree of parent categories
4210          */
4211         public function getParentCategoryTree( $children = array() ) {
4212                 $stack = array();
4213                 $parents = $this->getParentCategories();
4214
4215                 if ( $parents ) {
4216                         foreach ( $parents as $parent => $current ) {
4217                                 if ( array_key_exists( $parent, $children ) ) {
4218                                         # Circular reference
4219                                         $stack[$parent] = array();
4220                                 } else {
4221                                         $nt = Title::newFromText( $parent );
4222                                         if ( $nt ) {
4223                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4224                                         }
4225                                 }
4226                         }
4227                 }
4228
4229                 return $stack;
4230         }
4231
4232         /**
4233          * Get an associative array for selecting this title from
4234          * the "page" table
4235          *
4236          * @return Array suitable for the $where parameter of DB::select()
4237          */
4238         public function pageCond() {
4239                 if ( $this->mArticleID > 0 ) {
4240                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4241                         return array( 'page_id' => $this->mArticleID );
4242                 } else {
4243                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4244                 }
4245         }
4246
4247         /**
4248          * Get the revision ID of the previous revision
4249          *
4250          * @param int $revId Revision ID. Get the revision that was before this one.
4251          * @param int $flags Title::GAID_FOR_UPDATE
4252          * @return Int|Bool Old revision ID, or FALSE if none exists
4253          */
4254         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4255                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4256                 $revId = $db->selectField( 'revision', 'rev_id',
4257                         array(
4258                                 'rev_page' => $this->getArticleID( $flags ),
4259                                 'rev_id < ' . intval( $revId )
4260                         ),
4261                         __METHOD__,
4262                         array( 'ORDER BY' => 'rev_id DESC' )
4263                 );
4264
4265                 if ( $revId === false ) {
4266                         return false;
4267                 } else {
4268                         return intval( $revId );
4269                 }
4270         }
4271
4272         /**
4273          * Get the revision ID of the next revision
4274          *
4275          * @param int $revId Revision ID. Get the revision that was after this one.
4276          * @param int $flags Title::GAID_FOR_UPDATE
4277          * @return Int|Bool Next revision ID, or FALSE if none exists
4278          */
4279         public function getNextRevisionID( $revId, $flags = 0 ) {
4280                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4281                 $revId = $db->selectField( 'revision', 'rev_id',
4282                         array(
4283                                 'rev_page' => $this->getArticleID( $flags ),
4284                                 'rev_id > ' . intval( $revId )
4285                         ),
4286                         __METHOD__,
4287                         array( 'ORDER BY' => 'rev_id' )
4288                 );
4289
4290                 if ( $revId === false ) {
4291                         return false;
4292                 } else {
4293                         return intval( $revId );
4294                 }
4295         }
4296
4297         /**
4298          * Get the first revision of the page
4299          *
4300          * @param int $flags Title::GAID_FOR_UPDATE
4301          * @return Revision|Null if page doesn't exist
4302          */
4303         public function getFirstRevision( $flags = 0 ) {
4304                 $pageId = $this->getArticleID( $flags );
4305                 if ( $pageId ) {
4306                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4307                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4308                                 array( 'rev_page' => $pageId ),
4309                                 __METHOD__,
4310                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4311                         );
4312                         if ( $row ) {
4313                                 return new Revision( $row );
4314                         }
4315                 }
4316                 return null;
4317         }
4318
4319         /**
4320          * Get the oldest revision timestamp of this page
4321          *
4322          * @param int $flags Title::GAID_FOR_UPDATE
4323          * @return String: MW timestamp
4324          */
4325         public function getEarliestRevTime( $flags = 0 ) {
4326                 $rev = $this->getFirstRevision( $flags );
4327                 return $rev ? $rev->getTimestamp() : null;
4328         }
4329
4330         /**
4331          * Check if this is a new page
4332          *
4333          * @return bool
4334          */
4335         public function isNewPage() {
4336                 $dbr = wfGetDB( DB_SLAVE );
4337                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4338         }
4339
4340         /**
4341          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4342          *
4343          * @return bool
4344          */
4345         public function isBigDeletion() {
4346                 global $wgDeleteRevisionsLimit;
4347
4348                 if ( !$wgDeleteRevisionsLimit ) {
4349                         return false;
4350                 }
4351
4352                 $revCount = $this->estimateRevisionCount();
4353                 return $revCount > $wgDeleteRevisionsLimit;
4354         }
4355
4356         /**
4357          * Get the  approximate revision count of this page.
4358          *
4359          * @return int
4360          */
4361         public function estimateRevisionCount() {
4362                 if ( !$this->exists() ) {
4363                         return 0;
4364                 }
4365
4366                 if ( $this->mEstimateRevisions === null ) {
4367                         $dbr = wfGetDB( DB_SLAVE );
4368                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4369                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4370                 }
4371
4372                 return $this->mEstimateRevisions;
4373         }
4374
4375         /**
4376          * Get the number of revisions between the given revision.
4377          * Used for diffs and other things that really need it.
4378          *
4379          * @param int|Revision $old Old revision or rev ID (first before range)
4380          * @param int|Revision $new New revision or rev ID (first after range)
4381          * @return Int Number of revisions between these revisions.
4382          */
4383         public function countRevisionsBetween( $old, $new ) {
4384                 if ( !( $old instanceof Revision ) ) {
4385                         $old = Revision::newFromTitle( $this, (int)$old );
4386                 }
4387                 if ( !( $new instanceof Revision ) ) {
4388                         $new = Revision::newFromTitle( $this, (int)$new );
4389                 }
4390                 if ( !$old || !$new ) {
4391                         return 0; // nothing to compare
4392                 }
4393                 $dbr = wfGetDB( DB_SLAVE );
4394                 return (int)$dbr->selectField( 'revision', 'count(*)',
4395                         array(
4396                                 'rev_page' => $this->getArticleID(),
4397                                 'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4398                                 'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4399                         ),
4400                         __METHOD__
4401                 );
4402         }
4403
4404         /**
4405          * Get the number of authors between the given revisions or revision IDs.
4406          * Used for diffs and other things that really need it.
4407          *
4408          * @param int|Revision $old Old revision or rev ID (first before range by default)
4409          * @param int|Revision $new New revision or rev ID (first after range by default)
4410          * @param int $limit Maximum number of authors
4411          * @param string|array $options (Optional): Single option, or an array of options:
4412          *     'include_old' Include $old in the range; $new is excluded.
4413          *     'include_new' Include $new in the range; $old is excluded.
4414          *     'include_both' Include both $old and $new in the range.
4415          *     Unknown option values are ignored.
4416          * @return int Number of revision authors in the range; zero if not both revisions exist
4417          */
4418         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4419                 if ( !( $old instanceof Revision ) ) {
4420                         $old = Revision::newFromTitle( $this, (int)$old );
4421                 }
4422                 if ( !( $new instanceof Revision ) ) {
4423                         $new = Revision::newFromTitle( $this, (int)$new );
4424                 }
4425                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4426                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4427                 // in the sanity check below?
4428                 if ( !$old || !$new ) {
4429                         return 0; // nothing to compare
4430                 }
4431                 $old_cmp = '>';
4432                 $new_cmp = '<';
4433                 $options = (array)$options;
4434                 if ( in_array( 'include_old', $options ) ) {
4435                         $old_cmp = '>=';
4436                 }
4437                 if ( in_array( 'include_new', $options ) ) {
4438                         $new_cmp = '<=';
4439                 }
4440                 if ( in_array( 'include_both', $options ) ) {
4441                         $old_cmp = '>=';
4442                         $new_cmp = '<=';
4443                 }
4444                 // No DB query needed if $old and $new are the same or successive revisions:
4445                 if ( $old->getId() === $new->getId() ) {
4446                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4447                 } elseif ( $old->getId() === $new->getParentId() ) {
4448                         if ( $old_cmp === '>' || $new_cmp === '<' ) {
4449                                 return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4450                         }
4451                         return ( $old->getRawUserText() === $new->getRawUserText() ) ? 1 : 2;
4452                 }
4453                 $dbr = wfGetDB( DB_SLAVE );
4454                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4455                         array(
4456                                 'rev_page' => $this->getArticleID(),
4457                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4458                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4459                         ), __METHOD__,
4460                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4461                 );
4462                 return (int)$dbr->numRows( $res );
4463         }
4464
4465         /**
4466          * Compare with another title.
4467          *
4468          * @param $title Title
4469          * @return Bool
4470          */
4471         public function equals( Title $title ) {
4472                 // Note: === is necessary for proper matching of number-like titles.
4473                 return $this->getInterwiki() === $title->getInterwiki()
4474                         && $this->getNamespace() == $title->getNamespace()
4475                         && $this->getDBkey() === $title->getDBkey();
4476         }
4477
4478         /**
4479          * Check if this title is a subpage of another title
4480          *
4481          * @param $title Title
4482          * @return Bool
4483          */
4484         public function isSubpageOf( Title $title ) {
4485                 return $this->getInterwiki() === $title->getInterwiki()
4486                         && $this->getNamespace() == $title->getNamespace()
4487                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4488         }
4489
4490         /**
4491          * Check if page exists.  For historical reasons, this function simply
4492          * checks for the existence of the title in the page table, and will
4493          * thus return false for interwiki links, special pages and the like.
4494          * If you want to know if a title can be meaningfully viewed, you should
4495          * probably call the isKnown() method instead.
4496          *
4497          * @return Bool
4498          */
4499         public function exists() {
4500                 return $this->getArticleID() != 0;
4501         }
4502
4503         /**
4504          * Should links to this title be shown as potentially viewable (i.e. as
4505          * "bluelinks"), even if there's no record by this title in the page
4506          * table?
4507          *
4508          * This function is semi-deprecated for public use, as well as somewhat
4509          * misleadingly named.  You probably just want to call isKnown(), which
4510          * calls this function internally.
4511          *
4512          * (ISSUE: Most of these checks are cheap, but the file existence check
4513          * can potentially be quite expensive.  Including it here fixes a lot of
4514          * existing code, but we might want to add an optional parameter to skip
4515          * it and any other expensive checks.)
4516          *
4517          * @return Bool
4518          */
4519         public function isAlwaysKnown() {
4520                 $isKnown = null;
4521
4522                 /**
4523                  * Allows overriding default behavior for determining if a page exists.
4524                  * If $isKnown is kept as null, regular checks happen. If it's
4525                  * a boolean, this value is returned by the isKnown method.
4526                  *
4527                  * @since 1.20
4528                  *
4529                  * @param Title $title
4530                  * @param boolean|null $isKnown
4531                  */
4532                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4533
4534                 if ( !is_null( $isKnown ) ) {
4535                         return $isKnown;
4536                 }
4537
4538                 if ( $this->isExternal() ) {
4539                         return true;  // any interwiki link might be viewable, for all we know
4540                 }
4541
4542                 switch ( $this->mNamespace ) {
4543                         case NS_MEDIA:
4544                         case NS_FILE:
4545                                 // file exists, possibly in a foreign repo
4546                                 return (bool)wfFindFile( $this );
4547                         case NS_SPECIAL:
4548                                 // valid special page
4549                                 return SpecialPageFactory::exists( $this->getDBkey() );
4550                         case NS_MAIN:
4551                                 // selflink, possibly with fragment
4552                                 return $this->mDbkeyform == '';
4553                         case NS_MEDIAWIKI:
4554                                 // known system message
4555                                 return $this->hasSourceText() !== false;
4556                         default:
4557                                 return false;
4558                 }
4559         }
4560
4561         /**
4562          * Does this title refer to a page that can (or might) be meaningfully
4563          * viewed?  In particular, this function may be used to determine if
4564          * links to the title should be rendered as "bluelinks" (as opposed to
4565          * "redlinks" to non-existent pages).
4566          * Adding something else to this function will cause inconsistency
4567          * since LinkHolderArray calls isAlwaysKnown() and does its own
4568          * page existence check.
4569          *
4570          * @return Bool
4571          */
4572         public function isKnown() {
4573                 return $this->isAlwaysKnown() || $this->exists();
4574         }
4575
4576         /**
4577          * Does this page have source text?
4578          *
4579          * @return Boolean
4580          */
4581         public function hasSourceText() {
4582                 if ( $this->exists() ) {
4583                         return true;
4584                 }
4585
4586                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4587                         // If the page doesn't exist but is a known system message, default
4588                         // message content will be displayed, same for language subpages-
4589                         // Use always content language to avoid loading hundreds of languages
4590                         // to get the link color.
4591                         global $wgContLang;
4592                         list( $name, ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4593                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4594                         return $message->exists();
4595                 }
4596
4597                 return false;
4598         }
4599
4600         /**
4601          * Get the default message text or false if the message doesn't exist
4602          *
4603          * @return String or false
4604          */
4605         public function getDefaultMessageText() {
4606                 global $wgContLang;
4607
4608                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4609                         return false;
4610                 }
4611
4612                 list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4613                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4614
4615                 if ( $message->exists() ) {
4616                         return $message->plain();
4617                 } else {
4618                         return false;
4619                 }
4620         }
4621
4622         /**
4623          * Updates page_touched for this page; called from LinksUpdate.php
4624          *
4625          * @return Bool true if the update succeeded
4626          */
4627         public function invalidateCache() {
4628                 if ( wfReadOnly() ) {
4629                         return false;
4630                 }
4631
4632                 $method = __METHOD__;
4633                 $dbw = wfGetDB( DB_MASTER );
4634                 $conds = $this->pageCond();
4635                 $dbw->onTransactionIdle( function() use ( $dbw, $conds, $method ) {
4636                         $dbw->update(
4637                                 'page',
4638                                 array( 'page_touched' => $dbw->timestamp() ),
4639                                 $conds,
4640                                 $method
4641                         );
4642                 } );
4643
4644                 return true;
4645         }
4646
4647         /**
4648          * Update page_touched timestamps and send squid purge messages for
4649          * pages linking to this title. May be sent to the job queue depending
4650          * on the number of links. Typically called on create and delete.
4651          */
4652         public function touchLinks() {
4653                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4654                 $u->doUpdate();
4655
4656                 if ( $this->getNamespace() == NS_CATEGORY ) {
4657                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4658                         $u->doUpdate();
4659                 }
4660         }
4661
4662         /**
4663          * Get the last touched timestamp
4664          *
4665          * @param $db DatabaseBase: optional db
4666          * @return String last-touched timestamp
4667          */
4668         public function getTouched( $db = null ) {
4669                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
4670                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4671                 return $touched;
4672         }
4673
4674         /**
4675          * Get the timestamp when this page was updated since the user last saw it.
4676          *
4677          * @param $user User
4678          * @return String|Null
4679          */
4680         public function getNotificationTimestamp( $user = null ) {
4681                 global $wgUser, $wgShowUpdatedMarker;
4682                 // Assume current user if none given
4683                 if ( !$user ) {
4684                         $user = $wgUser;
4685                 }
4686                 // Check cache first
4687                 $uid = $user->getId();
4688                 // avoid isset here, as it'll return false for null entries
4689                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4690                         return $this->mNotificationTimestamp[$uid];
4691                 }
4692                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4693                         $this->mNotificationTimestamp[$uid] = false;
4694                         return $this->mNotificationTimestamp[$uid];
4695                 }
4696                 // Don't cache too much!
4697                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4698                         $this->mNotificationTimestamp = array();
4699                 }
4700                 $dbr = wfGetDB( DB_SLAVE );
4701                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4702                         'wl_notificationtimestamp',
4703                         array(
4704                                 'wl_user' => $user->getId(),
4705                                 'wl_namespace' => $this->getNamespace(),
4706                                 'wl_title' => $this->getDBkey(),
4707                         ),
4708                         __METHOD__
4709                 );
4710                 return $this->mNotificationTimestamp[$uid];
4711         }
4712
4713         /**
4714          * Generate strings used for xml 'id' names in monobook tabs
4715          *
4716          * @param string $prepend defaults to 'nstab-'
4717          * @return String XML 'id' name
4718          */
4719         public function getNamespaceKey( $prepend = 'nstab-' ) {
4720                 global $wgContLang;
4721                 // Gets the subject namespace if this title
4722                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4723                 // Checks if canonical namespace name exists for namespace
4724                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4725                         // Uses canonical namespace name
4726                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4727                 } else {
4728                         // Uses text of namespace
4729                         $namespaceKey = $this->getSubjectNsText();
4730                 }
4731                 // Makes namespace key lowercase
4732                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4733                 // Uses main
4734                 if ( $namespaceKey == '' ) {
4735                         $namespaceKey = 'main';
4736                 }
4737                 // Changes file to image for backwards compatibility
4738                 if ( $namespaceKey == 'file' ) {
4739                         $namespaceKey = 'image';
4740                 }
4741                 return $prepend . $namespaceKey;
4742         }
4743
4744         /**
4745          * Get all extant redirects to this Title
4746          *
4747          * @param int|Null $ns Single namespace to consider; NULL to consider all namespaces
4748          * @return Title[] Array of Title redirects to this title
4749          */
4750         public function getRedirectsHere( $ns = null ) {
4751                 $redirs = array();
4752
4753                 $dbr = wfGetDB( DB_SLAVE );
4754                 $where = array(
4755                         'rd_namespace' => $this->getNamespace(),
4756                         'rd_title' => $this->getDBkey(),
4757                         'rd_from = page_id'
4758                 );
4759                 if ( $this->isExternal() ) {
4760                         $where['rd_interwiki'] = $this->getInterwiki();
4761                 } else {
4762                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4763                 }
4764                 if ( !is_null( $ns ) ) {
4765                         $where['page_namespace'] = $ns;
4766                 }
4767
4768                 $res = $dbr->select(
4769                         array( 'redirect', 'page' ),
4770                         array( 'page_namespace', 'page_title' ),
4771                         $where,
4772                         __METHOD__
4773                 );
4774
4775                 foreach ( $res as $row ) {
4776                         $redirs[] = self::newFromRow( $row );
4777                 }
4778                 return $redirs;
4779         }
4780
4781         /**
4782          * Check if this Title is a valid redirect target
4783          *
4784          * @return Bool
4785          */
4786         public function isValidRedirectTarget() {
4787                 global $wgInvalidRedirectTargets;
4788
4789                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4790                 if ( $this->isSpecial( 'Userlogout' ) ) {
4791                         return false;
4792                 }
4793
4794                 foreach ( $wgInvalidRedirectTargets as $target ) {
4795                         if ( $this->isSpecial( $target ) ) {
4796                                 return false;
4797                         }
4798                 }
4799
4800                 return true;
4801         }
4802
4803         /**
4804          * Get a backlink cache object
4805          *
4806          * @return BacklinkCache
4807          */
4808         public function getBacklinkCache() {
4809                 return BacklinkCache::get( $this );
4810         }
4811
4812         /**
4813          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4814          *
4815          * @return Boolean
4816          */
4817         public function canUseNoindex() {
4818                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4819
4820                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4821                         ? $wgContentNamespaces
4822                         : $wgExemptFromUserRobotsControl;
4823
4824                 return !in_array( $this->mNamespace, $bannedNamespaces );
4825
4826         }
4827
4828         /**
4829          * Returns the raw sort key to be used for categories, with the specified
4830          * prefix.  This will be fed to Collation::getSortKey() to get a
4831          * binary sortkey that can be used for actual sorting.
4832          *
4833          * @param string $prefix The prefix to be used, specified using
4834          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4835          *   prefix.
4836          * @return string
4837          */
4838         public function getCategorySortkey( $prefix = '' ) {
4839                 $unprefixed = $this->getText();
4840
4841                 // Anything that uses this hook should only depend
4842                 // on the Title object passed in, and should probably
4843                 // tell the users to run updateCollations.php --force
4844                 // in order to re-sort existing category relations.
4845                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4846                 if ( $prefix !== '' ) {
4847                         # Separate with a line feed, so the unprefixed part is only used as
4848                         # a tiebreaker when two pages have the exact same prefix.
4849                         # In UCA, tab is the only character that can sort above LF
4850                         # so we strip both of them from the original prefix.
4851                         $prefix = strtr( $prefix, "\n\t", '  ' );
4852                         return "$prefix\n$unprefixed";
4853                 }
4854                 return $unprefixed;
4855         }
4856
4857         /**
4858          * Get the language in which the content of this page is written in
4859          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4860          * e.g. $wgLang (such as special pages, which are in the user language).
4861          *
4862          * @since 1.18
4863          * @return Language
4864          */
4865         public function getPageLanguage() {
4866                 global $wgLang, $wgLanguageCode;
4867                 wfProfileIn( __METHOD__ );
4868                 if ( $this->isSpecialPage() ) {
4869                         // special pages are in the user language
4870                         wfProfileOut( __METHOD__ );
4871                         return $wgLang;
4872                 }
4873
4874                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4875                         // Note that this may depend on user settings, so the cache should be only per-request.
4876                         // NOTE: ContentHandler::getPageLanguage() may need to load the content to determine the page language!
4877                         // Checking $wgLanguageCode hasn't changed for the benefit of unit tests.
4878                         $contentHandler = ContentHandler::getForTitle( $this );
4879                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4880                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4881                 } else {
4882                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4883                 }
4884                 wfProfileOut( __METHOD__ );
4885                 return $langObj;
4886         }
4887
4888         /**
4889          * Get the language in which the content of this page is written when
4890          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4891          * e.g. $wgLang (such as special pages, which are in the user language).
4892          *
4893          * @since 1.20
4894          * @return Language
4895          */
4896         public function getPageViewLanguage() {
4897                 global $wgLang;
4898
4899                 if ( $this->isSpecialPage() ) {
4900                         // If the user chooses a variant, the content is actually
4901                         // in a language whose code is the variant code.
4902                         $variant = $wgLang->getPreferredVariant();
4903                         if ( $wgLang->getCode() !== $variant ) {
4904                                 return Language::factory( $variant );
4905                         }
4906
4907                         return $wgLang;
4908                 }
4909
4910                 //NOTE: can't be cached persistently, depends on user settings
4911                 //NOTE: ContentHandler::getPageViewLanguage() may need to load the content to determine the page language!
4912                 $contentHandler = ContentHandler::getForTitle( $this );
4913                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4914                 return $pageLang;
4915         }
4916
4917         /**
4918          * Get a list of rendered edit notices for this page.
4919          *
4920          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4921          * they will already be wrapped in paragraphs.
4922          *
4923          * @since 1.21
4924          * @param int oldid Revision ID that's being edited
4925          * @return Array
4926          */
4927         public function getEditNotices( $oldid = 0 ) {
4928                 $notices = array();
4929
4930                 # Optional notices on a per-namespace and per-page basis
4931                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4932                 $editnotice_ns_message = wfMessage( $editnotice_ns );
4933                 if ( $editnotice_ns_message->exists() ) {
4934                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
4935                 }
4936                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4937                         $parts = explode( '/', $this->getDBkey() );
4938                         $editnotice_base = $editnotice_ns;
4939                         while ( count( $parts ) > 0 ) {
4940                                 $editnotice_base .= '-' . array_shift( $parts );
4941                                 $editnotice_base_msg = wfMessage( $editnotice_base );
4942                                 if ( $editnotice_base_msg->exists() ) {
4943                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
4944                                 }
4945                         }
4946                 } else {
4947                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
4948                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
4949                         $editnoticeMsg = wfMessage( $editnoticeText );
4950                         if ( $editnoticeMsg->exists() ) {
4951                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
4952                         }
4953                 }
4954
4955                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4956                 return $notices;
4957         }
4958 }