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          * Check if a Title fragment is set
1205          *
1206          * @return bool
1207          * @since 1.23
1208          */
1209         public function hasFragment() {
1210                 return $this->mFragment !== '';
1211         }
1212
1213         /**
1214          * Get the fragment in URL form, including the "#" character if there is one
1215          * @return String Fragment in URL form
1216          */
1217         public function getFragmentForURL() {
1218                 if ( !$this->hasFragment() ) {
1219                         return '';
1220                 } else {
1221                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1222                 }
1223         }
1224
1225         /**
1226          * Set the fragment for this title. Removes the first character from the
1227          * specified fragment before setting, so it assumes you're passing it with
1228          * an initial "#".
1229          *
1230          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1231          * Still in active use privately.
1232          *
1233          * @param string $fragment text
1234          */
1235         public function setFragment( $fragment ) {
1236                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1237         }
1238
1239         /**
1240          * Prefix some arbitrary text with the namespace or interwiki prefix
1241          * of this object
1242          *
1243          * @param string $name the text
1244          * @return String the prefixed text
1245          * @private
1246          */
1247         private function prefix( $name ) {
1248                 $p = '';
1249                 if ( $this->isExternal() ) {
1250                         $p = $this->mInterwiki . ':';
1251                 }
1252
1253                 if ( 0 != $this->mNamespace ) {
1254                         $p .= $this->getNsText() . ':';
1255                 }
1256                 return $p . $name;
1257         }
1258
1259         /**
1260          * Get the prefixed database key form
1261          *
1262          * @return String the prefixed title, with underscores and
1263          *  any interwiki and namespace prefixes
1264          */
1265         public function getPrefixedDBkey() {
1266                 $s = $this->prefix( $this->mDbkeyform );
1267                 $s = str_replace( ' ', '_', $s );
1268                 return $s;
1269         }
1270
1271         /**
1272          * Get the prefixed title with spaces.
1273          * This is the form usually used for display
1274          *
1275          * @return String the prefixed title, with spaces
1276          */
1277         public function getPrefixedText() {
1278                 if ( $this->mPrefixedText === null ) {
1279                         $s = $this->prefix( $this->mTextform );
1280                         $s = str_replace( '_', ' ', $s );
1281                         $this->mPrefixedText = $s;
1282                 }
1283                 return $this->mPrefixedText;
1284         }
1285
1286         /**
1287          * Return a string representation of this title
1288          *
1289          * @return String representation of this title
1290          */
1291         public function __toString() {
1292                 return $this->getPrefixedText();
1293         }
1294
1295         /**
1296          * Get the prefixed title with spaces, plus any fragment
1297          * (part beginning with '#')
1298          *
1299          * @return String the prefixed title, with spaces and the fragment, including '#'
1300          */
1301         public function getFullText() {
1302                 $text = $this->getPrefixedText();
1303                 if ( $this->hasFragment() ) {
1304                         $text .= '#' . $this->getFragment();
1305                 }
1306                 return $text;
1307         }
1308
1309         /**
1310          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1311          *
1312          * @par Example:
1313          * @code
1314          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1315          * # returns: 'Foo'
1316          * @endcode
1317          *
1318          * @return String Root name
1319          * @since 1.20
1320          */
1321         public function getRootText() {
1322                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1323                         return $this->getText();
1324                 }
1325
1326                 return strtok( $this->getText(), '/' );
1327         }
1328
1329         /**
1330          * Get the root page name title, i.e. the leftmost part before any slashes
1331          *
1332          * @par Example:
1333          * @code
1334          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1335          * # returns: Title{User:Foo}
1336          * @endcode
1337          *
1338          * @return Title Root title
1339          * @since 1.20
1340          */
1341         public function getRootTitle() {
1342                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1343         }
1344
1345         /**
1346          * Get the base page name without a namespace, i.e. the part before the subpage name
1347          *
1348          * @par Example:
1349          * @code
1350          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1351          * # returns: 'Foo/Bar'
1352          * @endcode
1353          *
1354          * @return String Base name
1355          */
1356         public function getBaseText() {
1357                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1358                         return $this->getText();
1359                 }
1360
1361                 $parts = explode( '/', $this->getText() );
1362                 # Don't discard the real title if there's no subpage involved
1363                 if ( count( $parts ) > 1 ) {
1364                         unset( $parts[count( $parts ) - 1] );
1365                 }
1366                 return implode( '/', $parts );
1367         }
1368
1369         /**
1370          * Get the base page name title, i.e. the part before the subpage name
1371          *
1372          * @par Example:
1373          * @code
1374          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1375          * # returns: Title{User:Foo/Bar}
1376          * @endcode
1377          *
1378          * @return Title Base title
1379          * @since 1.20
1380          */
1381         public function getBaseTitle() {
1382                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1383         }
1384
1385         /**
1386          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1387          *
1388          * @par Example:
1389          * @code
1390          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1391          * # returns: "Baz"
1392          * @endcode
1393          *
1394          * @return String Subpage name
1395          */
1396         public function getSubpageText() {
1397                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1398                         return $this->mTextform;
1399                 }
1400                 $parts = explode( '/', $this->mTextform );
1401                 return $parts[count( $parts ) - 1];
1402         }
1403
1404         /**
1405          * Get the title for a subpage of the current page
1406          *
1407          * @par Example:
1408          * @code
1409          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1410          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1411          * @endcode
1412          *
1413          * @param string $text The subpage name to add to the title
1414          * @return Title Subpage title
1415          * @since 1.20
1416          */
1417         public function getSubpage( $text ) {
1418                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1419         }
1420
1421         /**
1422          * Get the HTML-escaped displayable text form.
1423          * Used for the title field in <a> tags.
1424          *
1425          * @return String the text, including any prefixes
1426          * @deprecated since 1.19
1427          */
1428         public function getEscapedText() {
1429                 wfDeprecated( __METHOD__, '1.19' );
1430                 return htmlspecialchars( $this->getPrefixedText() );
1431         }
1432
1433         /**
1434          * Get a URL-encoded form of the subpage text
1435          *
1436          * @return String URL-encoded subpage name
1437          */
1438         public function getSubpageUrlForm() {
1439                 $text = $this->getSubpageText();
1440                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1441                 return $text;
1442         }
1443
1444         /**
1445          * Get a URL-encoded title (not an actual URL) including interwiki
1446          *
1447          * @return String the URL-encoded form
1448          */
1449         public function getPrefixedURL() {
1450                 $s = $this->prefix( $this->mDbkeyform );
1451                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1452                 return $s;
1453         }
1454
1455         /**
1456          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1457          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1458          * second argument named variant. This was deprecated in favor
1459          * of passing an array of option with a "variant" key
1460          * Once $query2 is removed for good, this helper can be dropped
1461          * and the wfArrayToCgi moved to getLocalURL();
1462          *
1463          * @since 1.19 (r105919)
1464          * @param $query
1465          * @param $query2 bool
1466          * @return String
1467          */
1468         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1469                 if ( $query2 !== false ) {
1470                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1471                                 "method called with a second parameter is deprecated. Add your " .
1472                                 "parameter to an array passed as the first parameter.", "1.19" );
1473                 }
1474                 if ( is_array( $query ) ) {
1475                         $query = wfArrayToCgi( $query );
1476                 }
1477                 if ( $query2 ) {
1478                         if ( is_string( $query2 ) ) {
1479                                 // $query2 is a string, we will consider this to be
1480                                 // a deprecated $variant argument and add it to the query
1481                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1482                         } else {
1483                                 $query2 = wfArrayToCgi( $query2 );
1484                         }
1485                         // If we have $query content add a & to it first
1486                         if ( $query ) {
1487                                 $query .= '&';
1488                         }
1489                         // Now append the queries together
1490                         $query .= $query2;
1491                 }
1492                 return $query;
1493         }
1494
1495         /**
1496          * Get a real URL referring to this title, with interwiki link and
1497          * fragment
1498          *
1499          * See getLocalURL for the arguments.
1500          *
1501          * @see self::getLocalURL
1502          * @see wfExpandUrl
1503          * @param $query
1504          * @param $query2 bool
1505          * @param $proto Protocol type to use in URL
1506          * @return String the URL
1507          */
1508         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1509                 $query = self::fixUrlQueryArgs( $query, $query2 );
1510
1511                 # Hand off all the decisions on urls to getLocalURL
1512                 $url = $this->getLocalURL( $query );
1513
1514                 # Expand the url to make it a full url. Note that getLocalURL has the
1515                 # potential to output full urls for a variety of reasons, so we use
1516                 # wfExpandUrl instead of simply prepending $wgServer
1517                 $url = wfExpandUrl( $url, $proto );
1518
1519                 # Finally, add the fragment.
1520                 $url .= $this->getFragmentForURL();
1521
1522                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1523                 return $url;
1524         }
1525
1526         /**
1527          * Get a URL with no fragment or server name.  If this page is generated
1528          * with action=render, $wgServer is prepended.
1529          *
1530          * @param string|array $query an optional query string,
1531          *   not used for interwiki links. Can be specified as an associative array as well,
1532          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1533          *   Some query patterns will trigger various shorturl path replacements.
1534          * @param $query2 Mixed: An optional secondary query array. This one MUST
1535          *   be an array. If a string is passed it will be interpreted as a deprecated
1536          *   variant argument and urlencoded into a variant= argument.
1537          *   This second query argument will be added to the $query
1538          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1539          *   pair in the first parameter array instead.
1540          *
1541          * @return String the URL
1542          */
1543         public function getLocalURL( $query = '', $query2 = false ) {
1544                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1545
1546                 $query = self::fixUrlQueryArgs( $query, $query2 );
1547
1548                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1549                 if ( $interwiki ) {
1550                         $namespace = $this->getNsText();
1551                         if ( $namespace != '' ) {
1552                                 # Can this actually happen? Interwikis shouldn't be parsed.
1553                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1554                                 $namespace .= ':';
1555                         }
1556                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1557                         $url = wfAppendQuery( $url, $query );
1558                 } else {
1559                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1560                         if ( $query == '' ) {
1561                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1562                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1563                         } else {
1564                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1565                                 $url = false;
1566                                 $matches = array();
1567
1568                                 if ( !empty( $wgActionPaths )
1569                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1570                                 ) {
1571                                         $action = urldecode( $matches[2] );
1572                                         if ( isset( $wgActionPaths[$action] ) ) {
1573                                                 $query = $matches[1];
1574                                                 if ( isset( $matches[4] ) ) {
1575                                                         $query .= $matches[4];
1576                                                 }
1577                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1578                                                 if ( $query != '' ) {
1579                                                         $url = wfAppendQuery( $url, $query );
1580                                                 }
1581                                         }
1582                                 }
1583
1584                                 if ( $url === false
1585                                         && $wgVariantArticlePath
1586                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1587                                         && $this->getPageLanguage()->hasVariants()
1588                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1589                                 ) {
1590                                         $variant = urldecode( $matches[1] );
1591                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1592                                                 // Only do the variant replacement if the given variant is a valid
1593                                                 // variant for the page's language.
1594                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1595                                                 $url = str_replace( '$1', $dbkey, $url );
1596                                         }
1597                                 }
1598
1599                                 if ( $url === false ) {
1600                                         if ( $query == '-' ) {
1601                                                 $query = '';
1602                                         }
1603                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1604                                 }
1605                         }
1606
1607                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1608
1609                         // @todo FIXME: This causes breakage in various places when we
1610                         // actually expected a local URL and end up with dupe prefixes.
1611                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1612                                 $url = $wgServer . $url;
1613                         }
1614                 }
1615                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1616                 return $url;
1617         }
1618
1619         /**
1620          * Get a URL that's the simplest URL that will be valid to link, locally,
1621          * to the current Title.  It includes the fragment, but does not include
1622          * the server unless action=render is used (or the link is external).  If
1623          * there's a fragment but the prefixed text is empty, we just return a link
1624          * to the fragment.
1625          *
1626          * The result obviously should not be URL-escaped, but does need to be
1627          * HTML-escaped if it's being output in HTML.
1628          *
1629          * See getLocalURL for the arguments.
1630          *
1631          * @param $query
1632          * @param $query2 bool
1633          * @param $proto Protocol to use; setting this will cause a full URL to be used
1634          * @see self::getLocalURL
1635          * @return String the URL
1636          */
1637         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1638                 wfProfileIn( __METHOD__ );
1639                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1640                         $ret = $this->getFullURL( $query, $query2, $proto );
1641                 } elseif ( $this->getPrefixedText() === '' && $this->getFragment() !== '' ) {
1642                         $ret = $this->getFragmentForURL();
1643                 } else {
1644                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1645                 }
1646                 wfProfileOut( __METHOD__ );
1647                 return $ret;
1648         }
1649
1650         /**
1651          * Get an HTML-escaped version of the URL form, suitable for
1652          * using in a link, without a server name or fragment
1653          *
1654          * See getLocalURL for the arguments.
1655          *
1656          * @see self::getLocalURL
1657          * @param $query string
1658          * @param $query2 bool|string
1659          * @return String the URL
1660          * @deprecated since 1.19
1661          */
1662         public function escapeLocalURL( $query = '', $query2 = false ) {
1663                 wfDeprecated( __METHOD__, '1.19' );
1664                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1665         }
1666
1667         /**
1668          * Get an HTML-escaped version of the URL form, suitable for
1669          * using in a link, including the server name and fragment
1670          *
1671          * See getLocalURL for the arguments.
1672          *
1673          * @see self::getLocalURL
1674          * @return String the URL
1675          * @deprecated since 1.19
1676          */
1677         public function escapeFullURL( $query = '', $query2 = false ) {
1678                 wfDeprecated( __METHOD__, '1.19' );
1679                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1680         }
1681
1682         /**
1683          * Get the URL form for an internal link.
1684          * - Used in various Squid-related code, in case we have a different
1685          * internal hostname for the server from the exposed one.
1686          *
1687          * This uses $wgInternalServer to qualify the path, or $wgServer
1688          * if $wgInternalServer is not set. If the server variable used is
1689          * protocol-relative, the URL will be expanded to http://
1690          *
1691          * See getLocalURL for the arguments.
1692          *
1693          * @see self::getLocalURL
1694          * @return String the URL
1695          */
1696         public function getInternalURL( $query = '', $query2 = false ) {
1697                 global $wgInternalServer, $wgServer;
1698                 $query = self::fixUrlQueryArgs( $query, $query2 );
1699                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1700                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1701                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1702                 return $url;
1703         }
1704
1705         /**
1706          * Get the URL for a canonical link, for use in things like IRC and
1707          * e-mail notifications. Uses $wgCanonicalServer and the
1708          * GetCanonicalURL hook.
1709          *
1710          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1711          *
1712          * See getLocalURL for the arguments.
1713          *
1714          * @see self::getLocalURL
1715          * @return string The URL
1716          * @since 1.18
1717          */
1718         public function getCanonicalURL( $query = '', $query2 = false ) {
1719                 $query = self::fixUrlQueryArgs( $query, $query2 );
1720                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1721                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1722                 return $url;
1723         }
1724
1725         /**
1726          * HTML-escaped version of getCanonicalURL()
1727          *
1728          * See getLocalURL for the arguments.
1729          *
1730          * @see self::getLocalURL
1731          * @since 1.18
1732          * @return string
1733          * @deprecated since 1.19
1734          */
1735         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1736                 wfDeprecated( __METHOD__, '1.19' );
1737                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1738         }
1739
1740         /**
1741          * Get the edit URL for this Title
1742          *
1743          * @return String the URL, or a null string if this is an
1744          *  interwiki link
1745          */
1746         public function getEditURL() {
1747                 if ( $this->isExternal() ) {
1748                         return '';
1749                 }
1750                 $s = $this->getLocalURL( 'action=edit' );
1751
1752                 return $s;
1753         }
1754
1755         /**
1756          * Is $wgUser watching this page?
1757          *
1758          * @deprecated in 1.20; use User::isWatched() instead.
1759          * @return Bool
1760          */
1761         public function userIsWatching() {
1762                 global $wgUser;
1763
1764                 if ( is_null( $this->mWatched ) ) {
1765                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1766                                 $this->mWatched = false;
1767                         } else {
1768                                 $this->mWatched = $wgUser->isWatched( $this );
1769                         }
1770                 }
1771                 return $this->mWatched;
1772         }
1773
1774         /**
1775          * Can $wgUser read this page?
1776          *
1777          * @deprecated in 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1778          * @return Bool
1779          * @todo fold these checks into userCan()
1780          */
1781         public function userCanRead() {
1782                 wfDeprecated( __METHOD__, '1.19' );
1783                 return $this->userCan( 'read' );
1784         }
1785
1786         /**
1787          * Can $user perform $action on this page?
1788          * This skips potentially expensive cascading permission checks
1789          * as well as avoids expensive error formatting
1790          *
1791          * Suitable for use for nonessential UI controls in common cases, but
1792          * _not_ for functional access control.
1793          *
1794          * May provide false positives, but should never provide a false negative.
1795          *
1796          * @param string $action action that permission needs to be checked for
1797          * @param $user User to check (since 1.19); $wgUser will be used if not
1798          *              provided.
1799          * @return Bool
1800          */
1801         public function quickUserCan( $action, $user = null ) {
1802                 return $this->userCan( $action, $user, false );
1803         }
1804
1805         /**
1806          * Can $user perform $action on this page?
1807          *
1808          * @param string $action action that permission needs to be checked for
1809          * @param $user User to check (since 1.19); $wgUser will be used if not
1810          *   provided.
1811          * @param bool $doExpensiveQueries Set this to false to avoid doing
1812          *   unnecessary queries.
1813          * @return Bool
1814          */
1815         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1816                 if ( !$user instanceof User ) {
1817                         global $wgUser;
1818                         $user = $wgUser;
1819                 }
1820                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries, true ) );
1821         }
1822
1823         /**
1824          * Can $user perform $action on this page?
1825          *
1826          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1827          *
1828          * @param string $action action that permission needs to be checked for
1829          * @param $user User to check
1830          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1831          *   queries by skipping checks for cascading protections and user blocks.
1832          * @param array $ignoreErrors of Strings Set this to a list of message keys
1833          *   whose corresponding errors may be ignored.
1834          * @return Array of arguments to wfMessage to explain permissions problems.
1835          */
1836         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
1837                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1838
1839                 // Remove the errors being ignored.
1840                 foreach ( $errors as $index => $error ) {
1841                         $error_key = is_array( $error ) ? $error[0] : $error;
1842
1843                         if ( in_array( $error_key, $ignoreErrors ) ) {
1844                                 unset( $errors[$index] );
1845                         }
1846                 }
1847
1848                 return $errors;
1849         }
1850
1851         /**
1852          * Permissions checks that fail most often, and which are easiest to test.
1853          *
1854          * @param string $action the action to check
1855          * @param $user User user to check
1856          * @param array $errors list of current errors
1857          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1858          * @param $short Boolean short circuit on first error
1859          *
1860          * @return Array list of errors
1861          */
1862         private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1863                 if ( !wfRunHooks( 'TitleQuickPermissions', array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) ) ) {
1864                         return $errors;
1865                 }
1866
1867                 if ( $action == 'create' ) {
1868                         if (
1869                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1870                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1871                         ) {
1872                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1873                         }
1874                 } elseif ( $action == 'move' ) {
1875                         if ( !$user->isAllowed( 'move-rootuserpages' )
1876                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1877                                 // Show user page-specific message only if the user can move other pages
1878                                 $errors[] = array( 'cant-move-user-page' );
1879                         }
1880
1881                         // Check if user is allowed to move files if it's a file
1882                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1883                                 $errors[] = array( 'movenotallowedfile' );
1884                         }
1885
1886                         if ( !$user->isAllowed( 'move' ) ) {
1887                                 // User can't move anything
1888                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1889                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1890                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1891                                         // custom message if logged-in users without any special rights can move
1892                                         $errors[] = array( 'movenologintext' );
1893                                 } else {
1894                                         $errors[] = array( 'movenotallowed' );
1895                                 }
1896                         }
1897                 } elseif ( $action == 'move-target' ) {
1898                         if ( !$user->isAllowed( 'move' ) ) {
1899                                 // User can't move anything
1900                                 $errors[] = array( 'movenotallowed' );
1901                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1902                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1903                                 // Show user page-specific message only if the user can move other pages
1904                                 $errors[] = array( 'cant-move-to-user-page' );
1905                         }
1906                 } elseif ( !$user->isAllowed( $action ) ) {
1907                         $errors[] = $this->missingPermissionError( $action, $short );
1908                 }
1909
1910                 return $errors;
1911         }
1912
1913         /**
1914          * Add the resulting error code to the errors array
1915          *
1916          * @param array $errors list of current errors
1917          * @param $result Mixed result of errors
1918          *
1919          * @return Array list of errors
1920          */
1921         private function resultToError( $errors, $result ) {
1922                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1923                         // A single array representing an error
1924                         $errors[] = $result;
1925                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
1926                         // A nested array representing multiple errors
1927                         $errors = array_merge( $errors, $result );
1928                 } elseif ( $result !== '' && is_string( $result ) ) {
1929                         // A string representing a message-id
1930                         $errors[] = array( $result );
1931                 } elseif ( $result === false ) {
1932                         // a generic "We don't want them to do that"
1933                         $errors[] = array( 'badaccess-group0' );
1934                 }
1935                 return $errors;
1936         }
1937
1938         /**
1939          * Check various permission hooks
1940          *
1941          * @param string $action the action to check
1942          * @param $user User user to check
1943          * @param array $errors list of current errors
1944          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1945          * @param $short Boolean short circuit on first error
1946          *
1947          * @return Array list of errors
1948          */
1949         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
1950                 // Use getUserPermissionsErrors instead
1951                 $result = '';
1952                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
1953                         return $result ? array() : array( array( 'badaccess-group0' ) );
1954                 }
1955                 // Check getUserPermissionsErrors hook
1956                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
1957                         $errors = $this->resultToError( $errors, $result );
1958                 }
1959                 // Check getUserPermissionsErrorsExpensive hook
1960                 if (
1961                         $doExpensiveQueries
1962                         && !( $short && count( $errors ) > 0 )
1963                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
1964                 ) {
1965                         $errors = $this->resultToError( $errors, $result );
1966                 }
1967
1968                 return $errors;
1969         }
1970
1971         /**
1972          * Check permissions on special pages & namespaces
1973          *
1974          * @param string $action the action to check
1975          * @param $user User user to check
1976          * @param array $errors list of current errors
1977          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1978          * @param $short Boolean short circuit on first error
1979          *
1980          * @return Array list of errors
1981          */
1982         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1983                 # Only 'createaccount' can be performed on special pages,
1984                 # which don't actually exist in the DB.
1985                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
1986                         $errors[] = array( 'ns-specialprotected' );
1987                 }
1988
1989                 # Check $wgNamespaceProtection for restricted namespaces
1990                 if ( $this->isNamespaceProtected( $user ) ) {
1991                         $ns = $this->mNamespace == NS_MAIN ?
1992                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
1993                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
1994                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
1995                 }
1996
1997                 return $errors;
1998         }
1999
2000         /**
2001          * Check CSS/JS sub-page permissions
2002          *
2003          * @param string $action the action to check
2004          * @param $user User user to check
2005          * @param array $errors list of current errors
2006          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2007          * @param $short Boolean short circuit on first error
2008          *
2009          * @return Array list of errors
2010          */
2011         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2012                 # Protect css/js subpages of user pages
2013                 # XXX: this might be better using restrictions
2014                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2015                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2016                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2017                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2018                                         $errors[] = array( 'mycustomcssprotected' );
2019                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2020                                         $errors[] = array( 'mycustomjsprotected' );
2021                                 }
2022                         } else {
2023                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2024                                         $errors[] = array( 'customcssprotected' );
2025                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2026                                         $errors[] = array( 'customjsprotected' );
2027                                 }
2028                         }
2029                 }
2030
2031                 return $errors;
2032         }
2033
2034         /**
2035          * Check against page_restrictions table requirements on this
2036          * page. The user must possess all required rights for this
2037          * action.
2038          *
2039          * @param string $action the action to check
2040          * @param $user User user to check
2041          * @param array $errors list of current errors
2042          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2043          * @param $short Boolean short circuit on first error
2044          *
2045          * @return Array list of errors
2046          */
2047         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2048                 foreach ( $this->getRestrictions( $action ) as $right ) {
2049                         // Backwards compatibility, rewrite sysop -> editprotected
2050                         if ( $right == 'sysop' ) {
2051                                 $right = 'editprotected';
2052                         }
2053                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2054                         if ( $right == 'autoconfirmed' ) {
2055                                 $right = 'editsemiprotected';
2056                         }
2057                         if ( $right == '' ) {
2058                                 continue;
2059                         }
2060                         if ( !$user->isAllowed( $right ) ) {
2061                                 $errors[] = array( 'protectedpagetext', $right );
2062                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2063                                 $errors[] = array( 'protectedpagetext', 'protect' );
2064                         }
2065                 }
2066
2067                 return $errors;
2068         }
2069
2070         /**
2071          * Check restrictions on cascading pages.
2072          *
2073          * @param string $action the action to check
2074          * @param $user User to check
2075          * @param array $errors list of current errors
2076          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2077          * @param $short Boolean short circuit on first error
2078          *
2079          * @return Array list of errors
2080          */
2081         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2082                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2083                         # We /could/ use the protection level on the source page, but it's
2084                         # fairly ugly as we have to establish a precedence hierarchy for pages
2085                         # included by multiple cascade-protected pages. So just restrict
2086                         # it to people with 'protect' permission, as they could remove the
2087                         # protection anyway.
2088                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2089                         # Cascading protection depends on more than this page...
2090                         # Several cascading protected pages may include this page...
2091                         # Check each cascading level
2092                         # This is only for protection restrictions, not for all actions
2093                         if ( isset( $restrictions[$action] ) ) {
2094                                 foreach ( $restrictions[$action] as $right ) {
2095                                         // Backwards compatibility, rewrite sysop -> editprotected
2096                                         if ( $right == 'sysop' ) {
2097                                                 $right = 'editprotected';
2098                                         }
2099                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2100                                         if ( $right == 'autoconfirmed' ) {
2101                                                 $right = 'editsemiprotected';
2102                                         }
2103                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2104                                                 $pages = '';
2105                                                 foreach ( $cascadingSources as $page ) {
2106                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2107                                                 }
2108                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2109                                         }
2110                                 }
2111                         }
2112                 }
2113
2114                 return $errors;
2115         }
2116
2117         /**
2118          * Check action permissions not already checked in checkQuickPermissions
2119          *
2120          * @param string $action the action to check
2121          * @param $user User to check
2122          * @param array $errors list of current errors
2123          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2124          * @param $short Boolean short circuit on first error
2125          *
2126          * @return Array list of errors
2127          */
2128         private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2129                 global $wgDeleteRevisionsLimit, $wgLang;
2130
2131                 if ( $action == 'protect' ) {
2132                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $doExpensiveQueries, true ) ) ) {
2133                                 // If they can't edit, they shouldn't protect.
2134                                 $errors[] = array( 'protect-cantedit' );
2135                         }
2136                 } elseif ( $action == 'create' ) {
2137                         $title_protection = $this->getTitleProtection();
2138                         if ( $title_protection ) {
2139                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2140                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2141                                 }
2142                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2143                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2144                                 }
2145                                 if ( $title_protection['pt_create_perm'] == ''
2146                                         || !$user->isAllowed( $title_protection['pt_create_perm'] )
2147                                 ) {
2148                                         $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
2149                                 }
2150                         }
2151                 } elseif ( $action == 'move' ) {
2152                         // Check for immobile pages
2153                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2154                                 // Specific message for this case
2155                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2156                         } elseif ( !$this->isMovable() ) {
2157                                 // Less specific message for rarer cases
2158                                 $errors[] = array( 'immobile-source-page' );
2159                         }
2160                 } elseif ( $action == 'move-target' ) {
2161                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2162                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2163                         } elseif ( !$this->isMovable() ) {
2164                                 $errors[] = array( 'immobile-target-page' );
2165                         }
2166                 } elseif ( $action == 'delete' ) {
2167                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2168                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2169                         ) {
2170                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2171                         }
2172                 }
2173                 return $errors;
2174         }
2175
2176         /**
2177          * Check that the user isn't blocked from editing.
2178          *
2179          * @param string $action the action to check
2180          * @param $user User to check
2181          * @param array $errors list of current errors
2182          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2183          * @param $short Boolean short circuit on first error
2184          *
2185          * @return Array list of errors
2186          */
2187         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2188                 // Account creation blocks handled at userlogin.
2189                 // Unblocking handled in SpecialUnblock
2190                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2191                         return $errors;
2192                 }
2193
2194                 global $wgEmailConfirmToEdit;
2195
2196                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2197                         $errors[] = array( 'confirmedittext' );
2198                 }
2199
2200                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2201                         // Don't block the user from editing their own talk page unless they've been
2202                         // explicitly blocked from that too.
2203                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2204                         // @todo FIXME: Pass the relevant context into this function.
2205                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2206                 }
2207
2208                 return $errors;
2209         }
2210
2211         /**
2212          * Check that the user is allowed to read this page.
2213          *
2214          * @param string $action the action to check
2215          * @param $user User to check
2216          * @param array $errors list of current errors
2217          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2218          * @param $short Boolean short circuit on first error
2219          *
2220          * @return Array list of errors
2221          */
2222         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2223                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2224
2225                 $whitelisted = false;
2226                 if ( User::isEveryoneAllowed( 'read' ) ) {
2227                         # Shortcut for public wikis, allows skipping quite a bit of code
2228                         $whitelisted = true;
2229                 } elseif ( $user->isAllowed( 'read' ) ) {
2230                         # If the user is allowed to read pages, he is allowed to read all pages
2231                         $whitelisted = true;
2232                 } elseif ( $this->isSpecial( 'Userlogin' )
2233                         || $this->isSpecial( 'ChangePassword' )
2234                         || $this->isSpecial( 'PasswordReset' )
2235                 ) {
2236                         # Always grant access to the login page.
2237                         # Even anons need to be able to log in.
2238                         $whitelisted = true;
2239                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2240                         # Time to check the whitelist
2241                         # Only do these checks is there's something to check against
2242                         $name = $this->getPrefixedText();
2243                         $dbName = $this->getPrefixedDBkey();
2244
2245                         // Check for explicit whitelisting with and without underscores
2246                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2247                                 $whitelisted = true;
2248                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2249                                 # Old settings might have the title prefixed with
2250                                 # a colon for main-namespace pages
2251                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2252                                         $whitelisted = true;
2253                                 }
2254                         } elseif ( $this->isSpecialPage() ) {
2255                                 # If it's a special page, ditch the subpage bit and check again
2256                                 $name = $this->getDBkey();
2257                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2258                                 if ( $name ) {
2259                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2260                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2261                                                 $whitelisted = true;
2262                                         }
2263                                 }
2264                         }
2265                 }
2266
2267                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2268                         $name = $this->getPrefixedText();
2269                         // Check for regex whitelisting
2270                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2271                                 if ( preg_match( $listItem, $name ) ) {
2272                                         $whitelisted = true;
2273                                         break;
2274                                 }
2275                         }
2276                 }
2277
2278                 if ( !$whitelisted ) {
2279                         # If the title is not whitelisted, give extensions a chance to do so...
2280                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2281                         if ( !$whitelisted ) {
2282                                 $errors[] = $this->missingPermissionError( $action, $short );
2283                         }
2284                 }
2285
2286                 return $errors;
2287         }
2288
2289         /**
2290          * Get a description array when the user doesn't have the right to perform
2291          * $action (i.e. when User::isAllowed() returns false)
2292          *
2293          * @param string $action the action to check
2294          * @param $short Boolean short circuit on first error
2295          * @return Array list of errors
2296          */
2297         private function missingPermissionError( $action, $short ) {
2298                 // We avoid expensive display logic for quickUserCan's and such
2299                 if ( $short ) {
2300                         return array( 'badaccess-group0' );
2301                 }
2302
2303                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2304                         User::getGroupsWithPermission( $action ) );
2305
2306                 if ( count( $groups ) ) {
2307                         global $wgLang;
2308                         return array(
2309                                 'badaccess-groups',
2310                                 $wgLang->commaList( $groups ),
2311                                 count( $groups )
2312                         );
2313                 } else {
2314                         return array( 'badaccess-group0' );
2315                 }
2316         }
2317
2318         /**
2319          * Can $user perform $action on this page? This is an internal function,
2320          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2321          * checks on wfReadOnly() and blocks)
2322          *
2323          * @param string $action action that permission needs to be checked for
2324          * @param $user User to check
2325          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2326          * @param bool $short Set this to true to stop after the first permission error.
2327          * @return Array of arrays of the arguments to wfMessage to explain permissions problems.
2328          */
2329         protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
2330                 wfProfileIn( __METHOD__ );
2331
2332                 # Read has special handling
2333                 if ( $action == 'read' ) {
2334                         $checks = array(
2335                                 'checkPermissionHooks',
2336                                 'checkReadPermissions',
2337                         );
2338                 } else {
2339                         $checks = array(
2340                                 'checkQuickPermissions',
2341                                 'checkPermissionHooks',
2342                                 'checkSpecialsAndNSPermissions',
2343                                 'checkCSSandJSPermissions',
2344                                 'checkPageRestrictions',
2345                                 'checkCascadingSourcesRestrictions',
2346                                 'checkActionPermissions',
2347                                 'checkUserBlock'
2348                         );
2349                 }
2350
2351                 $errors = array();
2352                 while ( count( $checks ) > 0 &&
2353                                 !( $short && count( $errors ) > 0 ) ) {
2354                         $method = array_shift( $checks );
2355                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2356                 }
2357
2358                 wfProfileOut( __METHOD__ );
2359                 return $errors;
2360         }
2361
2362         /**
2363          * Get a filtered list of all restriction types supported by this wiki.
2364          * @param bool $exists True to get all restriction types that apply to
2365          * titles that do exist, False for all restriction types that apply to
2366          * titles that do not exist
2367          * @return array
2368          */
2369         public static function getFilteredRestrictionTypes( $exists = true ) {
2370                 global $wgRestrictionTypes;
2371                 $types = $wgRestrictionTypes;
2372                 if ( $exists ) {
2373                         # Remove the create restriction for existing titles
2374                         $types = array_diff( $types, array( 'create' ) );
2375                 } else {
2376                         # Only the create and upload restrictions apply to non-existing titles
2377                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2378                 }
2379                 return $types;
2380         }
2381
2382         /**
2383          * Returns restriction types for the current Title
2384          *
2385          * @return array applicable restriction types
2386          */
2387         public function getRestrictionTypes() {
2388                 if ( $this->isSpecialPage() ) {
2389                         return array();
2390                 }
2391
2392                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2393
2394                 if ( $this->getNamespace() != NS_FILE ) {
2395                         # Remove the upload restriction for non-file titles
2396                         $types = array_diff( $types, array( 'upload' ) );
2397                 }
2398
2399                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2400
2401                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2402                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2403
2404                 return $types;
2405         }
2406
2407         /**
2408          * Is this title subject to title protection?
2409          * Title protection is the one applied against creation of such title.
2410          *
2411          * @return Mixed An associative array representing any existent title
2412          *   protection, or false if there's none.
2413          */
2414         private function getTitleProtection() {
2415                 // Can't protect pages in special namespaces
2416                 if ( $this->getNamespace() < 0 ) {
2417                         return false;
2418                 }
2419
2420                 // Can't protect pages that exist.
2421                 if ( $this->exists() ) {
2422                         return false;
2423                 }
2424
2425                 if ( !isset( $this->mTitleProtection ) ) {
2426                         $dbr = wfGetDB( DB_SLAVE );
2427                         $res = $dbr->select(
2428                                 'protected_titles',
2429                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2430                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2431                                 __METHOD__
2432                         );
2433
2434                         // fetchRow returns false if there are no rows.
2435                         $this->mTitleProtection = $dbr->fetchRow( $res );
2436                 }
2437                 return $this->mTitleProtection;
2438         }
2439
2440         /**
2441          * Update the title protection status
2442          *
2443          * @deprecated in 1.19; use WikiPage::doUpdateRestrictions() instead.
2444          * @param $create_perm String Permission required for creation
2445          * @param string $reason Reason for protection
2446          * @param string $expiry Expiry timestamp
2447          * @return boolean true
2448          */
2449         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2450                 wfDeprecated( __METHOD__, '1.19' );
2451
2452                 global $wgUser;
2453
2454                 $limit = array( 'create' => $create_perm );
2455                 $expiry = array( 'create' => $expiry );
2456
2457                 $page = WikiPage::factory( $this );
2458                 $cascade = false;
2459                 $status = $page->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $wgUser );
2460
2461                 return $status->isOK();
2462         }
2463
2464         /**
2465          * Remove any title protection due to page existing
2466          */
2467         public function deleteTitleProtection() {
2468                 $dbw = wfGetDB( DB_MASTER );
2469
2470                 $dbw->delete(
2471                         'protected_titles',
2472                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2473                         __METHOD__
2474                 );
2475                 $this->mTitleProtection = false;
2476         }
2477
2478         /**
2479          * Is this page "semi-protected" - the *only* protection levels are listed
2480          * in $wgSemiprotectedRestrictionLevels?
2481          *
2482          * @param string $action Action to check (default: edit)
2483          * @return Bool
2484          */
2485         public function isSemiProtected( $action = 'edit' ) {
2486                 global $wgSemiprotectedRestrictionLevels;
2487
2488                 $restrictions = $this->getRestrictions( $action );
2489                 $semi = $wgSemiprotectedRestrictionLevels;
2490                 if ( !$restrictions || !$semi ) {
2491                         // Not protected, or all protection is full protection
2492                         return false;
2493                 }
2494
2495                 // Remap autoconfirmed to editsemiprotected for BC
2496                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2497                         $semi[$key] = 'editsemiprotected';
2498                 }
2499                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2500                         $restrictions[$key] = 'editsemiprotected';
2501                 }
2502
2503                 return !array_diff( $restrictions, $semi );
2504         }
2505
2506         /**
2507          * Does the title correspond to a protected article?
2508          *
2509          * @param string $action the action the page is protected from,
2510          * by default checks all actions.
2511          * @return Bool
2512          */
2513         public function isProtected( $action = '' ) {
2514                 global $wgRestrictionLevels;
2515
2516                 $restrictionTypes = $this->getRestrictionTypes();
2517
2518                 # Special pages have inherent protection
2519                 if ( $this->isSpecialPage() ) {
2520                         return true;
2521                 }
2522
2523                 # Check regular protection levels
2524                 foreach ( $restrictionTypes as $type ) {
2525                         if ( $action == $type || $action == '' ) {
2526                                 $r = $this->getRestrictions( $type );
2527                                 foreach ( $wgRestrictionLevels as $level ) {
2528                                         if ( in_array( $level, $r ) && $level != '' ) {
2529                                                 return true;
2530                                         }
2531                                 }
2532                         }
2533                 }
2534
2535                 return false;
2536         }
2537
2538         /**
2539          * Determines if $user is unable to edit this page because it has been protected
2540          * by $wgNamespaceProtection.
2541          *
2542          * @param $user User object to check permissions
2543          * @return Bool
2544          */
2545         public function isNamespaceProtected( User $user ) {
2546                 global $wgNamespaceProtection;
2547
2548                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2549                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2550                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2551                                         return true;
2552                                 }
2553                         }
2554                 }
2555                 return false;
2556         }
2557
2558         /**
2559          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2560          *
2561          * @return Bool If the page is subject to cascading restrictions.
2562          */
2563         public function isCascadeProtected() {
2564                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2565                 return ( $sources > 0 );
2566         }
2567
2568         /**
2569          * Determines whether cascading protection sources have already been loaded from
2570          * the database.
2571          *
2572          * @param bool $getPages True to check if the pages are loaded, or false to check
2573          * if the status is loaded.
2574          * @return bool Whether or not the specified information has been loaded
2575          * @since 1.23
2576          */
2577         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2578                 return $getPages ? isset( $this->mCascadeSources ) : isset( $this->mHasCascadingRestrictions );
2579         }
2580
2581         /**
2582          * Cascading protection: Get the source of any cascading restrictions on this page.
2583          *
2584          * @param bool $getPages Whether or not to retrieve the actual pages
2585          *        that the restrictions have come from.
2586          * @return Mixed Array of Title objects of the pages from which cascading restrictions
2587          *     have come, false for none, or true if such restrictions exist, but $getPages
2588          *     was not set.  The restriction array is an array of each type, each of which
2589          *     contains a array of unique groups.
2590          */
2591         public function getCascadeProtectionSources( $getPages = true ) {
2592                 global $wgContLang;
2593                 $pagerestrictions = array();
2594
2595                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2596                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2597                 } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2598                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2599                 }
2600
2601                 wfProfileIn( __METHOD__ );
2602
2603                 $dbr = wfGetDB( DB_SLAVE );
2604
2605                 if ( $this->getNamespace() == NS_FILE ) {
2606                         $tables = array( 'imagelinks', 'page_restrictions' );
2607                         $where_clauses = array(
2608                                 'il_to' => $this->getDBkey(),
2609                                 'il_from=pr_page',
2610                                 'pr_cascade' => 1
2611                         );
2612                 } else {
2613                         $tables = array( 'templatelinks', 'page_restrictions' );
2614                         $where_clauses = array(
2615                                 'tl_namespace' => $this->getNamespace(),
2616                                 'tl_title' => $this->getDBkey(),
2617                                 'tl_from=pr_page',
2618                                 'pr_cascade' => 1
2619                         );
2620                 }
2621
2622                 if ( $getPages ) {
2623                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2624                                 'pr_expiry', 'pr_type', 'pr_level' );
2625                         $where_clauses[] = 'page_id=pr_page';
2626                         $tables[] = 'page';
2627                 } else {
2628                         $cols = array( 'pr_expiry' );
2629                 }
2630
2631                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2632
2633                 $sources = $getPages ? array() : false;
2634                 $now = wfTimestampNow();
2635                 $purgeExpired = false;
2636
2637                 foreach ( $res as $row ) {
2638                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2639                         if ( $expiry > $now ) {
2640                                 if ( $getPages ) {
2641                                         $page_id = $row->pr_page;
2642                                         $page_ns = $row->page_namespace;
2643                                         $page_title = $row->page_title;
2644                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2645                                         # Add groups needed for each restriction type if its not already there
2646                                         # Make sure this restriction type still exists
2647
2648                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2649                                                 $pagerestrictions[$row->pr_type] = array();
2650                                         }
2651
2652                                         if (
2653                                                 isset( $pagerestrictions[$row->pr_type] )
2654                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2655                                         ) {
2656                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2657                                         }
2658                                 } else {
2659                                         $sources = true;
2660                                 }
2661                         } else {
2662                                 // Trigger lazy purge of expired restrictions from the db
2663                                 $purgeExpired = true;
2664                         }
2665                 }
2666                 if ( $purgeExpired ) {
2667                         Title::purgeExpiredRestrictions();
2668                 }
2669
2670                 if ( $getPages ) {
2671                         $this->mCascadeSources = $sources;
2672                         $this->mCascadingRestrictions = $pagerestrictions;
2673                 } else {
2674                         $this->mHasCascadingRestrictions = $sources;
2675                 }
2676
2677                 wfProfileOut( __METHOD__ );
2678                 return array( $sources, $pagerestrictions );
2679         }
2680
2681         /**
2682          * Accessor for mRestrictionsLoaded
2683          *
2684          * @return bool Whether or not the page's restrictions have already been
2685          * loaded from the database
2686          * @since 1.23
2687          */
2688         public function areRestrictionsLoaded() {
2689                 return $this->mRestrictionsLoaded;
2690         }
2691
2692         /**
2693          * Accessor/initialisation for mRestrictions
2694          *
2695          * @param string $action action that permission needs to be checked for
2696          * @return Array of Strings the array of groups allowed to edit this article
2697          */
2698         public function getRestrictions( $action ) {
2699                 if ( !$this->mRestrictionsLoaded ) {
2700                         $this->loadRestrictions();
2701                 }
2702                 return isset( $this->mRestrictions[$action] )
2703                                 ? $this->mRestrictions[$action]
2704                                 : array();
2705         }
2706
2707         /**
2708          * Accessor/initialisation for mRestrictions
2709          *
2710          * @return Array of Arrays of Strings the first level indexed by
2711          * action, the second level containing the names of the groups
2712          * allowed to perform each action
2713          * @since 1.23
2714          */
2715         public function getAllRestrictions() {
2716                 if ( !$this->mRestrictionsLoaded ) {
2717                         $this->loadRestrictions();
2718                 }
2719                 return $this->mRestrictions;
2720         }
2721
2722         /**
2723          * Get the expiry time for the restriction against a given action
2724          *
2725          * @param $action
2726          * @return String|Bool 14-char timestamp, or 'infinity' if the page is protected forever
2727          *     or not protected at all, or false if the action is not recognised.
2728          */
2729         public function getRestrictionExpiry( $action ) {
2730                 if ( !$this->mRestrictionsLoaded ) {
2731                         $this->loadRestrictions();
2732                 }
2733                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2734         }
2735
2736         /**
2737          * Returns cascading restrictions for the current article
2738          *
2739          * @return Boolean
2740          */
2741         function areRestrictionsCascading() {
2742                 if ( !$this->mRestrictionsLoaded ) {
2743                         $this->loadRestrictions();
2744                 }
2745
2746                 return $this->mCascadeRestriction;
2747         }
2748
2749         /**
2750          * Loads a string into mRestrictions array
2751          *
2752          * @param $res Resource restrictions as an SQL result.
2753          * @param string $oldFashionedRestrictions comma-separated list of page
2754          *        restrictions from page table (pre 1.10)
2755          */
2756         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2757                 $rows = array();
2758
2759                 foreach ( $res as $row ) {
2760                         $rows[] = $row;
2761                 }
2762
2763                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2764         }
2765
2766         /**
2767          * Compiles list of active page restrictions from both page table (pre 1.10)
2768          * and page_restrictions table for this existing page.
2769          * Public for usage by LiquidThreads.
2770          *
2771          * @param array $rows of db result objects
2772          * @param string $oldFashionedRestrictions comma-separated list of page
2773          *        restrictions from page table (pre 1.10)
2774          */
2775         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2776                 global $wgContLang;
2777                 $dbr = wfGetDB( DB_SLAVE );
2778
2779                 $restrictionTypes = $this->getRestrictionTypes();
2780
2781                 foreach ( $restrictionTypes as $type ) {
2782                         $this->mRestrictions[$type] = array();
2783                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2784                 }
2785
2786                 $this->mCascadeRestriction = false;
2787
2788                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2789
2790                 if ( $oldFashionedRestrictions === null ) {
2791                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2792                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2793                 }
2794
2795                 if ( $oldFashionedRestrictions != '' ) {
2796
2797                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2798                                 $temp = explode( '=', trim( $restrict ) );
2799                                 if ( count( $temp ) == 1 ) {
2800                                         // old old format should be treated as edit/move restriction
2801                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2802                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2803                                 } else {
2804                                         $restriction = trim( $temp[1] );
2805                                         if ( $restriction != '' ) { //some old entries are empty
2806                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2807                                         }
2808                                 }
2809                         }
2810
2811                         $this->mOldRestrictions = true;
2812
2813                 }
2814
2815                 if ( count( $rows ) ) {
2816                         # Current system - load second to make them override.
2817                         $now = wfTimestampNow();
2818                         $purgeExpired = false;
2819
2820                         # Cycle through all the restrictions.
2821                         foreach ( $rows as $row ) {
2822
2823                                 // Don't take care of restrictions types that aren't allowed
2824                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2825                                         continue;
2826                                 }
2827
2828                                 // This code should be refactored, now that it's being used more generally,
2829                                 // But I don't really see any harm in leaving it in Block for now -werdna
2830                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2831
2832                                 // Only apply the restrictions if they haven't expired!
2833                                 if ( !$expiry || $expiry > $now ) {
2834                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2835                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2836
2837                                         $this->mCascadeRestriction |= $row->pr_cascade;
2838                                 } else {
2839                                         // Trigger a lazy purge of expired restrictions
2840                                         $purgeExpired = true;
2841                                 }
2842                         }
2843
2844                         if ( $purgeExpired ) {
2845                                 Title::purgeExpiredRestrictions();
2846                         }
2847                 }
2848
2849                 $this->mRestrictionsLoaded = true;
2850         }
2851
2852         /**
2853          * Load restrictions from the page_restrictions table
2854          *
2855          * @param string $oldFashionedRestrictions comma-separated list of page
2856          *        restrictions from page table (pre 1.10)
2857          */
2858         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2859                 global $wgContLang;
2860                 if ( !$this->mRestrictionsLoaded ) {
2861                         if ( $this->exists() ) {
2862                                 $dbr = wfGetDB( DB_SLAVE );
2863
2864                                 $res = $dbr->select(
2865                                         'page_restrictions',
2866                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2867                                         array( 'pr_page' => $this->getArticleID() ),
2868                                         __METHOD__
2869                                 );
2870
2871                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2872                         } else {
2873                                 $title_protection = $this->getTitleProtection();
2874
2875                                 if ( $title_protection ) {
2876                                         $now = wfTimestampNow();
2877                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2878
2879                                         if ( !$expiry || $expiry > $now ) {
2880                                                 // Apply the restrictions
2881                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2882                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2883                                         } else { // Get rid of the old restrictions
2884                                                 Title::purgeExpiredRestrictions();
2885                                                 $this->mTitleProtection = false;
2886                                         }
2887                                 } else {
2888                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2889                                 }
2890                                 $this->mRestrictionsLoaded = true;
2891                         }
2892                 }
2893         }
2894
2895         /**
2896          * Flush the protection cache in this object and force reload from the database.
2897          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2898          */
2899         public function flushRestrictions() {
2900                 $this->mRestrictionsLoaded = false;
2901                 $this->mTitleProtection = null;
2902         }
2903
2904         /**
2905          * Purge expired restrictions from the page_restrictions table
2906          */
2907         static function purgeExpiredRestrictions() {
2908                 if ( wfReadOnly() ) {
2909                         return;
2910                 }
2911
2912                 $method = __METHOD__;
2913                 $dbw = wfGetDB( DB_MASTER );
2914                 $dbw->onTransactionIdle( function() use ( $dbw, $method ) {
2915                         $dbw->delete(
2916                                 'page_restrictions',
2917                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2918                                 $method
2919                         );
2920                         $dbw->delete(
2921                                 'protected_titles',
2922                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2923                                 $method
2924                         );
2925                 } );
2926         }
2927
2928         /**
2929          * Does this have subpages?  (Warning, usually requires an extra DB query.)
2930          *
2931          * @return Bool
2932          */
2933         public function hasSubpages() {
2934                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
2935                         # Duh
2936                         return false;
2937                 }
2938
2939                 # We dynamically add a member variable for the purpose of this method
2940                 # alone to cache the result.  There's no point in having it hanging
2941                 # around uninitialized in every Title object; therefore we only add it
2942                 # if needed and don't declare it statically.
2943                 if ( !isset( $this->mHasSubpages ) ) {
2944                         $this->mHasSubpages = false;
2945                         $subpages = $this->getSubpages( 1 );
2946                         if ( $subpages instanceof TitleArray ) {
2947                                 $this->mHasSubpages = (bool)$subpages->count();
2948                         }
2949                 }
2950
2951                 return $this->mHasSubpages;
2952         }
2953
2954         /**
2955          * Get all subpages of this page.
2956          *
2957          * @param int $limit maximum number of subpages to fetch; -1 for no limit
2958          * @return mixed TitleArray, or empty array if this page's namespace
2959          *  doesn't allow subpages
2960          */
2961         public function getSubpages( $limit = -1 ) {
2962                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
2963                         return array();
2964                 }
2965
2966                 $dbr = wfGetDB( DB_SLAVE );
2967                 $conds['page_namespace'] = $this->getNamespace();
2968                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
2969                 $options = array();
2970                 if ( $limit > -1 ) {
2971                         $options['LIMIT'] = $limit;
2972                 }
2973                 $this->mSubpages = TitleArray::newFromResult(
2974                         $dbr->select( 'page',
2975                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
2976                                 $conds,
2977                                 __METHOD__,
2978                                 $options
2979                         )
2980                 );
2981                 return $this->mSubpages;
2982         }
2983
2984         /**
2985          * Is there a version of this page in the deletion archive?
2986          *
2987          * @return Int the number of archived revisions
2988          */
2989         public function isDeleted() {
2990                 if ( $this->getNamespace() < 0 ) {
2991                         $n = 0;
2992                 } else {
2993                         $dbr = wfGetDB( DB_SLAVE );
2994
2995                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
2996                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2997                                 __METHOD__
2998                         );
2999                         if ( $this->getNamespace() == NS_FILE ) {
3000                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3001                                         array( 'fa_name' => $this->getDBkey() ),
3002                                         __METHOD__
3003                                 );
3004                         }
3005                 }
3006                 return (int)$n;
3007         }
3008
3009         /**
3010          * Is there a version of this page in the deletion archive?
3011          *
3012          * @return Boolean
3013          */
3014         public function isDeletedQuick() {
3015                 if ( $this->getNamespace() < 0 ) {
3016                         return false;
3017                 }
3018                 $dbr = wfGetDB( DB_SLAVE );
3019                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3020                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3021                         __METHOD__
3022                 );
3023                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3024                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3025                                 array( 'fa_name' => $this->getDBkey() ),
3026                                 __METHOD__
3027                         );
3028                 }
3029                 return $deleted;
3030         }
3031
3032         /**
3033          * Get the article ID for this Title from the link cache,
3034          * adding it if necessary
3035          *
3036          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select
3037          *  for update
3038          * @return Int the ID
3039          */
3040         public function getArticleID( $flags = 0 ) {
3041                 if ( $this->getNamespace() < 0 ) {
3042                         $this->mArticleID = 0;
3043                         return $this->mArticleID;
3044                 }
3045                 $linkCache = LinkCache::singleton();
3046                 if ( $flags & self::GAID_FOR_UPDATE ) {
3047                         $oldUpdate = $linkCache->forUpdate( true );
3048                         $linkCache->clearLink( $this );
3049                         $this->mArticleID = $linkCache->addLinkObj( $this );
3050                         $linkCache->forUpdate( $oldUpdate );
3051                 } else {
3052                         if ( -1 == $this->mArticleID ) {
3053                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3054                         }
3055                 }
3056                 return $this->mArticleID;
3057         }
3058
3059         /**
3060          * Is this an article that is a redirect page?
3061          * Uses link cache, adding it if necessary
3062          *
3063          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3064          * @return Bool
3065          */
3066         public function isRedirect( $flags = 0 ) {
3067                 if ( !is_null( $this->mRedirect ) ) {
3068                         return $this->mRedirect;
3069                 }
3070                 # Calling getArticleID() loads the field from cache as needed
3071                 if ( !$this->getArticleID( $flags ) ) {
3072                         $this->mRedirect = false;
3073                         return $this->mRedirect;
3074                 }
3075
3076                 $linkCache = LinkCache::singleton();
3077                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3078                 if ( $cached === null ) {
3079                         # Trust LinkCache's state over our own
3080                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3081                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3082                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3083                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3084                         # LinkCache to refresh its data from the master.
3085                         $this->mRedirect = false;
3086                         return $this->mRedirect;
3087                 }
3088
3089                 $this->mRedirect = (bool)$cached;
3090
3091                 return $this->mRedirect;
3092         }
3093
3094         /**
3095          * What is the length of this page?
3096          * Uses link cache, adding it if necessary
3097          *
3098          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3099          * @return Int
3100          */
3101         public function getLength( $flags = 0 ) {
3102                 if ( $this->mLength != -1 ) {
3103                         return $this->mLength;
3104                 }
3105                 # Calling getArticleID() loads the field from cache as needed
3106                 if ( !$this->getArticleID( $flags ) ) {
3107                         $this->mLength = 0;
3108                         return $this->mLength;
3109                 }
3110                 $linkCache = LinkCache::singleton();
3111                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3112                 if ( $cached === null ) {
3113                         # Trust LinkCache's state over our own, as for isRedirect()
3114                         $this->mLength = 0;
3115                         return $this->mLength;
3116                 }
3117
3118                 $this->mLength = intval( $cached );
3119
3120                 return $this->mLength;
3121         }
3122
3123         /**
3124          * What is the page_latest field for this page?
3125          *
3126          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3127          * @return Int or 0 if the page doesn't exist
3128          */
3129         public function getLatestRevID( $flags = 0 ) {
3130                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3131                         return intval( $this->mLatestID );
3132                 }
3133                 # Calling getArticleID() loads the field from cache as needed
3134                 if ( !$this->getArticleID( $flags ) ) {
3135                         $this->mLatestID = 0;
3136                         return $this->mLatestID;
3137                 }
3138                 $linkCache = LinkCache::singleton();
3139                 $linkCache->addLinkObj( $this );
3140                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3141                 if ( $cached === null ) {
3142                         # Trust LinkCache's state over our own, as for isRedirect()
3143                         $this->mLatestID = 0;
3144                         return $this->mLatestID;
3145                 }
3146
3147                 $this->mLatestID = intval( $cached );
3148
3149                 return $this->mLatestID;
3150         }
3151
3152         /**
3153          * This clears some fields in this object, and clears any associated
3154          * keys in the "bad links" section of the link cache.
3155          *
3156          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3157          * loading of the new page_id. It's also called from
3158          * WikiPage::doDeleteArticleReal()
3159          *
3160          * @param int $newid the new Article ID
3161          */
3162         public function resetArticleID( $newid ) {
3163                 $linkCache = LinkCache::singleton();
3164                 $linkCache->clearLink( $this );
3165
3166                 if ( $newid === false ) {
3167                         $this->mArticleID = -1;
3168                 } else {
3169                         $this->mArticleID = intval( $newid );
3170                 }
3171                 $this->mRestrictionsLoaded = false;
3172                 $this->mRestrictions = array();
3173                 $this->mRedirect = null;
3174                 $this->mLength = -1;
3175                 $this->mLatestID = false;
3176                 $this->mContentModel = false;
3177                 $this->mEstimateRevisions = null;
3178                 $this->mPageLanguage = false;
3179         }
3180
3181         /**
3182          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3183          *
3184          * @param string $text containing title to capitalize
3185          * @param int $ns namespace index, defaults to NS_MAIN
3186          * @return String containing capitalized title
3187          */
3188         public static function capitalize( $text, $ns = NS_MAIN ) {
3189                 global $wgContLang;
3190
3191                 if ( MWNamespace::isCapitalized( $ns ) ) {
3192                         return $wgContLang->ucfirst( $text );
3193                 } else {
3194                         return $text;
3195                 }
3196         }
3197
3198         /**
3199          * Secure and split - main initialisation function for this object
3200          *
3201          * Assumes that mDbkeyform has been set, and is urldecoded
3202          * and uses underscores, but not otherwise munged.  This function
3203          * removes illegal characters, splits off the interwiki and
3204          * namespace prefixes, sets the other forms, and canonicalizes
3205          * everything.
3206          *
3207          * @return Bool true on success
3208          */
3209         private function secureAndSplit() {
3210                 global $wgContLang, $wgLocalInterwiki;
3211
3212                 # Initialisation
3213                 $this->mInterwiki = $this->mFragment = '';
3214                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3215
3216                 $dbkey = $this->mDbkeyform;
3217
3218                 # Strip Unicode bidi override characters.
3219                 # Sometimes they slip into cut-n-pasted page titles, where the
3220                 # override chars get included in list displays.
3221                 $dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );
3222
3223                 # Clean up whitespace
3224                 # Note: use of the /u option on preg_replace here will cause
3225                 # input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
3226                 # conveniently disabling them.
3227                 $dbkey = preg_replace( '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u', '_', $dbkey );
3228                 $dbkey = trim( $dbkey, '_' );
3229
3230                 if ( strpos( $dbkey, UTF8_REPLACEMENT ) !== false ) {
3231                         # Contained illegal UTF-8 sequences or forbidden Unicode chars.
3232                         return false;
3233                 }
3234
3235                 $this->mDbkeyform = $dbkey;
3236
3237                 # Initial colon indicates main namespace rather than specified default
3238                 # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
3239                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3240                         $this->mNamespace = NS_MAIN;
3241                         $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
3242                         $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
3243                 }
3244
3245                 if ( $dbkey == '' ) {
3246                         return false;
3247                 }
3248
3249                 # Namespace or interwiki prefix
3250                 $firstPass = true;
3251                 $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
3252                 do {
3253                         $m = array();
3254                         if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
3255                                 $p = $m[1];
3256                                 if ( ( $ns = $wgContLang->getNsIndex( $p ) ) !== false ) {
3257                                         # Ordinary namespace
3258                                         $dbkey = $m[2];
3259                                         $this->mNamespace = $ns;
3260                                         # For Talk:X pages, check if X has a "namespace" prefix
3261                                         if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
3262                                                 if ( $wgContLang->getNsIndex( $x[1] ) ) {
3263                                                         # Disallow Talk:File:x type titles...
3264                                                         return false;
3265                                                 } elseif ( Interwiki::isValidInterwiki( $x[1] ) ) {
3266                                                         # Disallow Talk:Interwiki:x type titles...
3267                                                         return false;
3268                                                 }
3269                                         }
3270                                 } elseif ( Interwiki::isValidInterwiki( $p ) ) {
3271                                         if ( !$firstPass ) {
3272                                                 # Can't make a local interwiki link to an interwiki link.
3273                                                 # That's just crazy!
3274                                                 return false;
3275                                         }
3276
3277                                         # Interwiki link
3278                                         $dbkey = $m[2];
3279                                         $this->mInterwiki = $wgContLang->lc( $p );
3280
3281                                         # Redundant interwiki prefix to the local wiki
3282                                         if ( $wgLocalInterwiki !== false
3283                                                 && 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki )
3284                                         ) {
3285                                                 if ( $dbkey == '' ) {
3286                                                         # Can't have an empty self-link
3287                                                         return false;
3288                                                 }
3289                                                 $this->mInterwiki = '';
3290                                                 $firstPass = false;
3291                                                 # Do another namespace split...
3292                                                 continue;
3293                                         }
3294
3295                                         # If there's an initial colon after the interwiki, that also
3296                                         # resets the default namespace
3297                                         if ( $dbkey !== '' && $dbkey[0] == ':' ) {
3298                                                 $this->mNamespace = NS_MAIN;
3299                                                 $dbkey = substr( $dbkey, 1 );
3300                                         }
3301                                 }
3302                                 # If there's no recognized interwiki or namespace,
3303                                 # then let the colon expression be part of the title.
3304                         }
3305                         break;
3306                 } while ( true );
3307
3308                 # We already know that some pages won't be in the database!
3309                 if ( $this->isExternal() || NS_SPECIAL == $this->mNamespace ) {
3310                         $this->mArticleID = 0;
3311                 }
3312                 $fragment = strstr( $dbkey, '#' );
3313                 if ( false !== $fragment ) {
3314                         $this->setFragment( $fragment );
3315                         $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
3316                         # remove whitespace again: prevents "Foo_bar_#"
3317                         # becoming "Foo_bar_"
3318                         $dbkey = preg_replace( '/_*$/', '', $dbkey );
3319                 }
3320
3321                 # Reject illegal characters.
3322                 $rxTc = self::getTitleInvalidRegex();
3323                 if ( preg_match( $rxTc, $dbkey ) ) {
3324                         return false;
3325                 }
3326
3327                 # Pages with "/./" or "/../" appearing in the URLs will often be un-
3328                 # reachable due to the way web browsers deal with 'relative' URLs.
3329                 # Also, they conflict with subpage syntax.  Forbid them explicitly.
3330                 if (
3331                         strpos( $dbkey, '.' ) !== false &&
3332                         (
3333                                 $dbkey === '.' || $dbkey === '..' ||
3334                                 strpos( $dbkey, './' ) === 0 ||
3335                                 strpos( $dbkey, '../' ) === 0 ||
3336                                 strpos( $dbkey, '/./' ) !== false ||
3337                                 strpos( $dbkey, '/../' ) !== false ||
3338                                 substr( $dbkey, -2 ) == '/.' ||
3339                                 substr( $dbkey, -3 ) == '/..'
3340                         )
3341                 ) {
3342                         return false;
3343                 }
3344
3345                 # Magic tilde sequences? Nu-uh!
3346                 if ( strpos( $dbkey, '~~~' ) !== false ) {
3347                         return false;
3348                 }
3349
3350                 # Limit the size of titles to 255 bytes. This is typically the size of the
3351                 # underlying database field. We make an exception for special pages, which
3352                 # don't need to be stored in the database, and may edge over 255 bytes due
3353                 # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
3354                 if (
3355                         ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 )
3356                         || strlen( $dbkey ) > 512
3357                 ) {
3358                         return false;
3359                 }
3360
3361                 # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
3362                 # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
3363                 # other site might be case-sensitive.
3364                 $this->mUserCaseDBKey = $dbkey;
3365                 if ( !$this->isExternal() ) {
3366                         $dbkey = self::capitalize( $dbkey, $this->mNamespace );
3367                 }
3368
3369                 # Can't make a link to a namespace alone... "empty" local links can only be
3370                 # self-links with a fragment identifier.
3371                 if ( $dbkey == '' && !$this->isExternal() && $this->mNamespace != NS_MAIN ) {
3372                         return false;
3373                 }
3374
3375                 // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
3376                 // IP names are not allowed for accounts, and can only be referring to
3377                 // edits from the IP. Given '::' abbreviations and caps/lowercaps,
3378                 // there are numerous ways to present the same IP. Having sp:contribs scan
3379                 // them all is silly and having some show the edits and others not is
3380                 // inconsistent. Same for talk/userpages. Keep them normalized instead.
3381                 $dbkey = ( $this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK )
3382                         ? IP::sanitizeIP( $dbkey )
3383                         : $dbkey;
3384
3385                 // Any remaining initial :s are illegal.
3386                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3387                         return false;
3388                 }
3389
3390                 # Fill fields
3391                 $this->mDbkeyform = $dbkey;
3392                 $this->mUrlform = wfUrlencode( $dbkey );
3393
3394                 $this->mTextform = str_replace( '_', ' ', $dbkey );
3395
3396                 return true;
3397         }
3398
3399         /**
3400          * Get an array of Title objects linking to this Title
3401          * Also stores the IDs in the link cache.
3402          *
3403          * WARNING: do not use this function on arbitrary user-supplied titles!
3404          * On heavily-used templates it will max out the memory.
3405          *
3406          * @param array $options may be FOR UPDATE
3407          * @param string $table table name
3408          * @param string $prefix fields prefix
3409          * @return Array of Title objects linking here
3410          */
3411         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3412                 if ( count( $options ) > 0 ) {
3413                         $db = wfGetDB( DB_MASTER );
3414                 } else {
3415                         $db = wfGetDB( DB_SLAVE );
3416                 }
3417
3418                 $res = $db->select(
3419                         array( 'page', $table ),
3420                         self::getSelectFields(),
3421                         array(
3422                                 "{$prefix}_from=page_id",
3423                                 "{$prefix}_namespace" => $this->getNamespace(),
3424                                 "{$prefix}_title" => $this->getDBkey() ),
3425                         __METHOD__,
3426                         $options
3427                 );
3428
3429                 $retVal = array();
3430                 if ( $res->numRows() ) {
3431                         $linkCache = LinkCache::singleton();
3432                         foreach ( $res as $row ) {
3433                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3434                                 if ( $titleObj ) {
3435                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3436                                         $retVal[] = $titleObj;
3437                                 }
3438                         }
3439                 }
3440                 return $retVal;
3441         }
3442
3443         /**
3444          * Get an array of Title objects using this Title as a template
3445          * Also stores the IDs in the link cache.
3446          *
3447          * WARNING: do not use this function on arbitrary user-supplied titles!
3448          * On heavily-used templates it will max out the memory.
3449          *
3450          * @param array $options may be FOR UPDATE
3451          * @return Array of Title the Title objects linking here
3452          */
3453         public function getTemplateLinksTo( $options = array() ) {
3454                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3455         }
3456
3457         /**
3458          * Get an array of Title objects linked from this Title
3459          * Also stores the IDs in the link cache.
3460          *
3461          * WARNING: do not use this function on arbitrary user-supplied titles!
3462          * On heavily-used templates it will max out the memory.
3463          *
3464          * @param array $options may be FOR UPDATE
3465          * @param string $table table name
3466          * @param string $prefix fields prefix
3467          * @return Array of Title objects linking here
3468          */
3469         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3470                 global $wgContentHandlerUseDB;
3471
3472                 $id = $this->getArticleID();
3473
3474                 # If the page doesn't exist; there can't be any link from this page
3475                 if ( !$id ) {
3476                         return array();
3477                 }
3478
3479                 if ( count( $options ) > 0 ) {
3480                         $db = wfGetDB( DB_MASTER );
3481                 } else {
3482                         $db = wfGetDB( DB_SLAVE );
3483                 }
3484
3485                 $namespaceFiled = "{$prefix}_namespace";
3486                 $titleField = "{$prefix}_title";
3487
3488                 $fields = array( $namespaceFiled, $titleField, 'page_id', 'page_len', 'page_is_redirect', 'page_latest' );
3489                 if ( $wgContentHandlerUseDB ) {
3490                         $fields[] = 'page_content_model';
3491                 }
3492
3493                 $res = $db->select(
3494                         array( $table, 'page' ),
3495                         $fields,
3496                         array( "{$prefix}_from" => $id ),
3497                         __METHOD__,
3498                         $options,
3499                         array( 'page' => array( 'LEFT JOIN', array( "page_namespace=$namespaceFiled", "page_title=$titleField" ) ) )
3500                 );
3501
3502                 $retVal = array();
3503                 if ( $res->numRows() ) {
3504                         $linkCache = LinkCache::singleton();
3505                         foreach ( $res as $row ) {
3506                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3507                                 if ( $titleObj ) {
3508                                         if ( $row->page_id ) {
3509                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3510                                         } else {
3511                                                 $linkCache->addBadLinkObj( $titleObj );
3512                                         }
3513                                         $retVal[] = $titleObj;
3514                                 }
3515                         }
3516                 }
3517                 return $retVal;
3518         }
3519
3520         /**
3521          * Get an array of Title objects used on this Title as a template
3522          * Also stores the IDs in the link cache.
3523          *
3524          * WARNING: do not use this function on arbitrary user-supplied titles!
3525          * On heavily-used templates it will max out the memory.
3526          *
3527          * @param array $options may be FOR UPDATE
3528          * @return Array of Title the Title objects used here
3529          */
3530         public function getTemplateLinksFrom( $options = array() ) {
3531                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3532         }
3533
3534         /**
3535          * Get an array of Title objects referring to non-existent articles linked from this page
3536          *
3537          * @todo check if needed (used only in SpecialBrokenRedirects.php, and should use redirect table in this case)
3538          * @return Array of Title the Title objects
3539          */
3540         public function getBrokenLinksFrom() {
3541                 if ( $this->getArticleID() == 0 ) {
3542                         # All links from article ID 0 are false positives
3543                         return array();
3544                 }
3545
3546                 $dbr = wfGetDB( DB_SLAVE );
3547                 $res = $dbr->select(
3548                         array( 'page', 'pagelinks' ),
3549                         array( 'pl_namespace', 'pl_title' ),
3550                         array(
3551                                 'pl_from' => $this->getArticleID(),
3552                                 'page_namespace IS NULL'
3553                         ),
3554                         __METHOD__, array(),
3555                         array(
3556                                 'page' => array(
3557                                         'LEFT JOIN',
3558                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3559                                 )
3560                         )
3561                 );
3562
3563                 $retVal = array();
3564                 foreach ( $res as $row ) {
3565                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3566                 }
3567                 return $retVal;
3568         }
3569
3570         /**
3571          * Get a list of URLs to purge from the Squid cache when this
3572          * page changes
3573          *
3574          * @return Array of String the URLs
3575          */
3576         public function getSquidURLs() {
3577                 $urls = array(
3578                         $this->getInternalURL(),
3579                         $this->getInternalURL( 'action=history' )
3580                 );
3581
3582                 $pageLang = $this->getPageLanguage();
3583                 if ( $pageLang->hasVariants() ) {
3584                         $variants = $pageLang->getVariants();
3585                         foreach ( $variants as $vCode ) {
3586                                 $urls[] = $this->getInternalURL( '', $vCode );
3587                         }
3588                 }
3589
3590                 // If we are looking at a css/js user subpage, purge the action=raw.
3591                 if ( $this->isJsSubpage() ) {
3592                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3593                 } elseif ( $this->isCssSubpage() ) {
3594                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3595                 }
3596
3597                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3598                 return $urls;
3599         }
3600
3601         /**
3602          * Purge all applicable Squid URLs
3603          */
3604         public function purgeSquid() {
3605                 global $wgUseSquid;
3606                 if ( $wgUseSquid ) {
3607                         $urls = $this->getSquidURLs();
3608                         $u = new SquidUpdate( $urls );
3609                         $u->doUpdate();
3610                 }
3611         }
3612
3613         /**
3614          * Move this page without authentication
3615          *
3616          * @param $nt Title the new page Title
3617          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3618          */
3619         public function moveNoAuth( &$nt ) {
3620                 return $this->moveTo( $nt, false );
3621         }
3622
3623         /**
3624          * Check whether a given move operation would be valid.
3625          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3626          *
3627          * @param $nt Title the new title
3628          * @param bool $auth indicates whether $wgUser's permissions
3629          *  should be checked
3630          * @param string $reason is the log summary of the move, used for spam checking
3631          * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
3632          */
3633         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3634                 global $wgUser, $wgContentHandlerUseDB;
3635
3636                 $errors = array();
3637                 if ( !$nt ) {
3638                         // Normally we'd add this to $errors, but we'll get
3639                         // lots of syntax errors if $nt is not an object
3640                         return array( array( 'badtitletext' ) );
3641                 }
3642                 if ( $this->equals( $nt ) ) {
3643                         $errors[] = array( 'selfmove' );
3644                 }
3645                 if ( !$this->isMovable() ) {
3646                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3647                 }
3648                 if ( $nt->isExternal() ) {
3649                         $errors[] = array( 'immobile-target-namespace-iw' );
3650                 }
3651                 if ( !$nt->isMovable() ) {
3652                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3653                 }
3654
3655                 $oldid = $this->getArticleID();
3656                 $newid = $nt->getArticleID();
3657
3658                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3659                         $errors[] = array( 'articleexists' );
3660                 }
3661                 if (
3662                         ( $this->getDBkey() == '' ) ||
3663                         ( !$oldid ) ||
3664                         ( $nt->getDBkey() == '' )
3665                 ) {
3666                         $errors[] = array( 'badarticleerror' );
3667                 }
3668
3669                 // Content model checks
3670                 if ( !$wgContentHandlerUseDB &&
3671                                 $this->getContentModel() !== $nt->getContentModel() ) {
3672                         // can't move a page if that would change the page's content model
3673                         $errors[] = array(
3674                                 'bad-target-model',
3675                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3676                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3677                         );
3678                 }
3679
3680                 // Image-specific checks
3681                 if ( $this->getNamespace() == NS_FILE ) {
3682                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3683                 }
3684
3685                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3686                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3687                 }
3688
3689                 if ( $auth ) {
3690                         $errors = wfMergeErrorArrays( $errors,
3691                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3692                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3693                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3694                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3695                 }
3696
3697                 $match = EditPage::matchSummarySpamRegex( $reason );
3698                 if ( $match !== false ) {
3699                         // This is kind of lame, won't display nice
3700                         $errors[] = array( 'spamprotectiontext' );
3701                 }
3702
3703                 $err = null;
3704                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3705                         $errors[] = array( 'hookaborted', $err );
3706                 }
3707
3708                 # The move is allowed only if (1) the target doesn't exist, or
3709                 # (2) the target is a redirect to the source, and has no history
3710                 # (so we can undo bad moves right after they're done).
3711
3712                 if ( 0 != $newid ) { # Target exists; check for validity
3713                         if ( !$this->isValidMoveTarget( $nt ) ) {
3714                                 $errors[] = array( 'articleexists' );
3715                         }
3716                 } else {
3717                         $tp = $nt->getTitleProtection();
3718                         $right = $tp['pt_create_perm'];
3719                         if ( $right == 'sysop' ) {
3720                                 $right = 'editprotected'; // B/C
3721                         }
3722                         if ( $right == 'autoconfirmed' ) {
3723                                 $right = 'editsemiprotected'; // B/C
3724                         }
3725                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3726                                 $errors[] = array( 'cantmove-titleprotected' );
3727                         }
3728                 }
3729                 if ( empty( $errors ) ) {
3730                         return true;
3731                 }
3732                 return $errors;
3733         }
3734
3735         /**
3736          * Check if the requested move target is a valid file move target
3737          * @param Title $nt Target title
3738          * @return array List of errors
3739          */
3740         protected function validateFileMoveOperation( $nt ) {
3741                 global $wgUser;
3742
3743                 $errors = array();
3744
3745                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3746
3747                 $file = wfLocalFile( $this );
3748                 if ( $file->exists() ) {
3749                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3750                                 $errors[] = array( 'imageinvalidfilename' );
3751                         }
3752                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3753                                 $errors[] = array( 'imagetypemismatch' );
3754                         }
3755                 }
3756
3757                 if ( $nt->getNamespace() != NS_FILE ) {
3758                         $errors[] = array( 'imagenocrossnamespace' );
3759                         // From here we want to do checks on a file object, so if we can't
3760                         // create one, we must return.
3761                         return $errors;
3762                 }
3763
3764                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3765
3766                 $destFile = wfLocalFile( $nt );
3767                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3768                         $errors[] = array( 'file-exists-sharedrepo' );
3769                 }
3770
3771                 return $errors;
3772         }
3773
3774         /**
3775          * Move a title to a new location
3776          *
3777          * @param $nt Title the new title
3778          * @param bool $auth indicates whether $wgUser's permissions
3779          *  should be checked
3780          * @param string $reason the reason for the move
3781          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3782          *  Ignored if the user doesn't have the suppressredirect right.
3783          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3784          */
3785         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3786                 global $wgUser;
3787                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3788                 if ( is_array( $err ) ) {
3789                         // Auto-block user's IP if the account was "hard" blocked
3790                         $wgUser->spreadAnyEditBlock();
3791                         return $err;
3792                 }
3793                 // Check suppressredirect permission
3794                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3795                         $createRedirect = true;
3796                 }
3797
3798                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3799
3800                 // If it is a file, move it first.
3801                 // It is done before all other moving stuff is done because it's hard to revert.
3802                 $dbw = wfGetDB( DB_MASTER );
3803                 if ( $this->getNamespace() == NS_FILE ) {
3804                         $file = wfLocalFile( $this );
3805                         if ( $file->exists() ) {
3806                                 $status = $file->move( $nt );
3807                                 if ( !$status->isOk() ) {
3808                                         return $status->getErrorsArray();
3809                                 }
3810                         }
3811                         // Clear RepoGroup process cache
3812                         RepoGroup::singleton()->clearCache( $this );
3813                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3814                 }
3815
3816                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3817                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3818                 $protected = $this->isProtected();
3819
3820                 // Do the actual move
3821                 $this->moveToInternal( $nt, $reason, $createRedirect );
3822
3823                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3824                 // cl_timestamp, which may disturb time-based lists on some sites.
3825                 $prefixes = $dbw->select(
3826                         'categorylinks',
3827                         array( 'cl_sortkey_prefix', 'cl_to' ),
3828                         array( 'cl_from' => $pageid ),
3829                         __METHOD__
3830                 );
3831                 foreach ( $prefixes as $prefixRow ) {
3832                         $prefix = $prefixRow->cl_sortkey_prefix;
3833                         $catTo = $prefixRow->cl_to;
3834                         $dbw->update( 'categorylinks',
3835                                 array(
3836                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3837                                                 $nt->getCategorySortkey( $prefix ) ),
3838                                         'cl_timestamp=cl_timestamp' ),
3839                                 array(
3840                                         'cl_from' => $pageid,
3841                                         'cl_to' => $catTo ),
3842                                 __METHOD__
3843                         );
3844                 }
3845
3846                 $redirid = $this->getArticleID();
3847
3848                 if ( $protected ) {
3849                         # Protect the redirect title as the title used to be...
3850                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3851                                 array(
3852                                         'pr_page' => $redirid,
3853                                         'pr_type' => 'pr_type',
3854                                         'pr_level' => 'pr_level',
3855                                         'pr_cascade' => 'pr_cascade',
3856                                         'pr_user' => 'pr_user',
3857                                         'pr_expiry' => 'pr_expiry'
3858                                 ),
3859                                 array( 'pr_page' => $pageid ),
3860                                 __METHOD__,
3861                                 array( 'IGNORE' )
3862                         );
3863                         # Update the protection log
3864                         $log = new LogPage( 'protect' );
3865                         $comment = wfMessage(
3866                                 'prot_1movedto2',
3867                                 $this->getPrefixedText(),
3868                                 $nt->getPrefixedText()
3869                         )->inContentLanguage()->text();
3870                         if ( $reason ) {
3871                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3872                         }
3873                         // @todo FIXME: $params?
3874                         $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ), $wgUser );
3875                 }
3876
3877                 # Update watchlists
3878                 $oldnamespace = MWNamespace::getSubject( $this->getNamespace() );
3879                 $newnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3880                 $oldtitle = $this->getDBkey();
3881                 $newtitle = $nt->getDBkey();
3882
3883                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3884                         WatchedItem::duplicateEntries( $this, $nt );
3885                 }
3886
3887                 $dbw->commit( __METHOD__ );
3888
3889                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
3890                 return true;
3891         }
3892
3893         /**
3894          * Move page to a title which is either a redirect to the
3895          * source page or nonexistent
3896          *
3897          * @param $nt Title the page to move to, which should be a redirect or nonexistent
3898          * @param string $reason The reason for the move
3899          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3900          *   if the user has the suppressredirect right
3901          * @throws MWException
3902          */
3903         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3904                 global $wgUser, $wgContLang;
3905
3906                 if ( $nt->exists() ) {
3907                         $moveOverRedirect = true;
3908                         $logType = 'move_redir';
3909                 } else {
3910                         $moveOverRedirect = false;
3911                         $logType = 'move';
3912                 }
3913
3914                 if ( $createRedirect ) {
3915                         $contentHandler = ContentHandler::getForTitle( $this );
3916                         $redirectContent = $contentHandler->makeRedirectContent( $nt,
3917                                 wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3918
3919                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3920                 } else {
3921                         $redirectContent = null;
3922                 }
3923
3924                 $logEntry = new ManualLogEntry( 'move', $logType );
3925                 $logEntry->setPerformer( $wgUser );
3926                 $logEntry->setTarget( $this );
3927                 $logEntry->setComment( $reason );
3928                 $logEntry->setParameters( array(
3929                         '4::target' => $nt->getPrefixedText(),
3930                         '5::noredir' => $redirectContent ? '0': '1',
3931                 ) );
3932
3933                 $formatter = LogFormatter::newFromEntry( $logEntry );
3934                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3935                 $comment = $formatter->getPlainActionText();
3936                 if ( $reason ) {
3937                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3938                 }
3939                 # Truncate for whole multibyte characters.
3940                 $comment = $wgContLang->truncate( $comment, 255 );
3941
3942                 $oldid = $this->getArticleID();
3943
3944                 $dbw = wfGetDB( DB_MASTER );
3945
3946                 $newpage = WikiPage::factory( $nt );
3947
3948                 if ( $moveOverRedirect ) {
3949                         $newid = $nt->getArticleID();
3950                         $newcontent = $newpage->getContent();
3951
3952                         # Delete the old redirect. We don't save it to history since
3953                         # by definition if we've got here it's rather uninteresting.
3954                         # We have to remove it so that the next step doesn't trigger
3955                         # a conflict on the unique namespace+title index...
3956                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3957
3958                         $newpage->doDeleteUpdates( $newid, $newcontent );
3959                 }
3960
3961                 # Save a null revision in the page's history notifying of the move
3962                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
3963                 if ( !is_object( $nullRevision ) ) {
3964                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3965                 }
3966
3967                 $nullRevision->insertOn( $dbw );
3968
3969                 # Change the name of the target page:
3970                 $dbw->update( 'page',
3971                         /* SET */ array(
3972                                 'page_namespace' => $nt->getNamespace(),
3973                                 'page_title' => $nt->getDBkey(),
3974                         ),
3975                         /* WHERE */ array( 'page_id' => $oldid ),
3976                         __METHOD__
3977                 );
3978
3979                 // clean up the old title before reset article id - bug 45348
3980                 if ( !$redirectContent ) {
3981                         WikiPage::onArticleDelete( $this );
3982                 }
3983
3984                 $this->resetArticleID( 0 ); // 0 == non existing
3985                 $nt->resetArticleID( $oldid );
3986                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
3987
3988                 $newpage->updateRevisionOn( $dbw, $nullRevision );
3989
3990                 wfRunHooks( 'NewRevisionFromEditComplete',
3991                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
3992
3993                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
3994
3995                 if ( !$moveOverRedirect ) {
3996                         WikiPage::onArticleCreate( $nt );
3997                 }
3998
3999                 # Recreate the redirect, this time in the other direction.
4000                 if ( $redirectContent ) {
4001                         $redirectArticle = WikiPage::factory( $this );
4002                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
4003                         $newid = $redirectArticle->insertOn( $dbw );
4004                         if ( $newid ) { // sanity
4005                                 $this->resetArticleID( $newid );
4006                                 $redirectRevision = new Revision( array(
4007                                         'title' => $this, // for determining the default content model
4008                                         'page' => $newid,
4009                                         'comment' => $comment,
4010                                         'content' => $redirectContent ) );
4011                                 $redirectRevision->insertOn( $dbw );
4012                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
4013
4014                                 wfRunHooks( 'NewRevisionFromEditComplete',
4015                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
4016
4017                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
4018                         }
4019                 }
4020
4021                 # Log the move
4022                 $logid = $logEntry->insert();
4023                 $logEntry->publish( $logid );
4024         }
4025
4026         /**
4027          * Move this page's subpages to be subpages of $nt
4028          *
4029          * @param $nt Title Move target
4030          * @param bool $auth Whether $wgUser's permissions should be checked
4031          * @param string $reason The reason for the move
4032          * @param bool $createRedirect Whether to create redirects from the old subpages to
4033          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4034          * @return mixed array with old page titles as keys, and strings (new page titles) or
4035          *     arrays (errors) as values, or an error array with numeric indices if no pages
4036          *     were moved
4037          */
4038         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
4039                 global $wgMaximumMovedPages;
4040                 // Check permissions
4041                 if ( !$this->userCan( 'move-subpages' ) ) {
4042                         return array( 'cant-move-subpages' );
4043                 }
4044                 // Do the source and target namespaces support subpages?
4045                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4046                         return array( 'namespace-nosubpages',
4047                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
4048                 }
4049                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4050                         return array( 'namespace-nosubpages',
4051                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
4052                 }
4053
4054                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4055                 $retval = array();
4056                 $count = 0;
4057                 foreach ( $subpages as $oldSubpage ) {
4058                         $count++;
4059                         if ( $count > $wgMaximumMovedPages ) {
4060                                 $retval[$oldSubpage->getPrefixedTitle()] =
4061                                                 array( 'movepage-max-pages',
4062                                                         $wgMaximumMovedPages );
4063                                 break;
4064                         }
4065
4066                         // We don't know whether this function was called before
4067                         // or after moving the root page, so check both
4068                         // $this and $nt
4069                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4070                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4071                         ) {
4072                                 // When moving a page to a subpage of itself,
4073                                 // don't move it twice
4074                                 continue;
4075                         }
4076                         $newPageName = preg_replace(
4077                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4078                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4079                                         $oldSubpage->getDBkey() );
4080                         if ( $oldSubpage->isTalkPage() ) {
4081                                 $newNs = $nt->getTalkPage()->getNamespace();
4082                         } else {
4083                                 $newNs = $nt->getSubjectPage()->getNamespace();
4084                         }
4085                         # Bug 14385: we need makeTitleSafe because the new page names may
4086                         # be longer than 255 characters.
4087                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4088
4089                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4090                         if ( $success === true ) {
4091                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4092                         } else {
4093                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4094                         }
4095                 }
4096                 return $retval;
4097         }
4098
4099         /**
4100          * Checks if this page is just a one-rev redirect.
4101          * Adds lock, so don't use just for light purposes.
4102          *
4103          * @return Bool
4104          */
4105         public function isSingleRevRedirect() {
4106                 global $wgContentHandlerUseDB;
4107
4108                 $dbw = wfGetDB( DB_MASTER );
4109
4110                 # Is it a redirect?
4111                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4112                 if ( $wgContentHandlerUseDB ) {
4113                         $fields[] = 'page_content_model';
4114                 }
4115
4116                 $row = $dbw->selectRow( 'page',
4117                         $fields,
4118                         $this->pageCond(),
4119                         __METHOD__,
4120                         array( 'FOR UPDATE' )
4121                 );
4122                 # Cache some fields we may want
4123                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4124                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4125                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4126                 $this->mContentModel = $row && isset( $row->page_content_model ) ? strval( $row->page_content_model ) : false;
4127                 if ( !$this->mRedirect ) {
4128                         return false;
4129                 }
4130                 # Does the article have a history?
4131                 $row = $dbw->selectField( array( 'page', 'revision' ),
4132                         'rev_id',
4133                         array( 'page_namespace' => $this->getNamespace(),
4134                                 'page_title' => $this->getDBkey(),
4135                                 'page_id=rev_page',
4136                                 'page_latest != rev_id'
4137                         ),
4138                         __METHOD__,
4139                         array( 'FOR UPDATE' )
4140                 );
4141                 # Return true if there was no history
4142                 return ( $row === false );
4143         }
4144
4145         /**
4146          * Checks if $this can be moved to a given Title
4147          * - Selects for update, so don't call it unless you mean business
4148          *
4149          * @param $nt Title the new title to check
4150          * @return Bool
4151          */
4152         public function isValidMoveTarget( $nt ) {
4153                 # Is it an existing file?
4154                 if ( $nt->getNamespace() == NS_FILE ) {
4155                         $file = wfLocalFile( $nt );
4156                         if ( $file->exists() ) {
4157                                 wfDebug( __METHOD__ . ": file exists\n" );
4158                                 return false;
4159                         }
4160                 }
4161                 # Is it a redirect with no history?
4162                 if ( !$nt->isSingleRevRedirect() ) {
4163                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4164                         return false;
4165                 }
4166                 # Get the article text
4167                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4168                 if ( !is_object( $rev ) ) {
4169                         return false;
4170                 }
4171                 $content = $rev->getContent();
4172                 # Does the redirect point to the source?
4173                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4174                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4175
4176                 if ( $redirTitle ) {
4177                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4178                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4179                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4180                                 return false;
4181                         } else {
4182                                 return true;
4183                         }
4184                 } else {
4185                         # Fail safe (not a redirect after all. strange.)
4186                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4187                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4188                         return false;
4189                 }
4190         }
4191
4192         /**
4193          * Get categories to which this Title belongs and return an array of
4194          * categories' names.
4195          *
4196          * @return Array of parents in the form:
4197          *        $parent => $currentarticle
4198          */
4199         public function getParentCategories() {
4200                 global $wgContLang;
4201
4202                 $data = array();
4203
4204                 $titleKey = $this->getArticleID();
4205
4206                 if ( $titleKey === 0 ) {
4207                         return $data;
4208                 }
4209
4210                 $dbr = wfGetDB( DB_SLAVE );
4211
4212                 $res = $dbr->select(
4213                         'categorylinks',
4214                         'cl_to',
4215                         array( 'cl_from' => $titleKey ),
4216                         __METHOD__
4217                 );
4218
4219                 if ( $res->numRows() > 0 ) {
4220                         foreach ( $res as $row ) {
4221                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4222                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4223                         }
4224                 }
4225                 return $data;
4226         }
4227
4228         /**
4229          * Get a tree of parent categories
4230          *
4231          * @param array $children with the children in the keys, to check for circular refs
4232          * @return Array Tree of parent categories
4233          */
4234         public function getParentCategoryTree( $children = array() ) {
4235                 $stack = array();
4236                 $parents = $this->getParentCategories();
4237
4238                 if ( $parents ) {
4239                         foreach ( $parents as $parent => $current ) {
4240                                 if ( array_key_exists( $parent, $children ) ) {
4241                                         # Circular reference
4242                                         $stack[$parent] = array();
4243                                 } else {
4244                                         $nt = Title::newFromText( $parent );
4245                                         if ( $nt ) {
4246                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4247                                         }
4248                                 }
4249                         }
4250                 }
4251
4252                 return $stack;
4253         }
4254
4255         /**
4256          * Get an associative array for selecting this title from
4257          * the "page" table
4258          *
4259          * @return Array suitable for the $where parameter of DB::select()
4260          */
4261         public function pageCond() {
4262                 if ( $this->mArticleID > 0 ) {
4263                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4264                         return array( 'page_id' => $this->mArticleID );
4265                 } else {
4266                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4267                 }
4268         }
4269
4270         /**
4271          * Get the revision ID of the previous revision
4272          *
4273          * @param int $revId Revision ID. Get the revision that was before this one.
4274          * @param int $flags Title::GAID_FOR_UPDATE
4275          * @return Int|Bool Old revision ID, or FALSE if none exists
4276          */
4277         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4278                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4279                 $revId = $db->selectField( 'revision', 'rev_id',
4280                         array(
4281                                 'rev_page' => $this->getArticleID( $flags ),
4282                                 'rev_id < ' . intval( $revId )
4283                         ),
4284                         __METHOD__,
4285                         array( 'ORDER BY' => 'rev_id DESC' )
4286                 );
4287
4288                 if ( $revId === false ) {
4289                         return false;
4290                 } else {
4291                         return intval( $revId );
4292                 }
4293         }
4294
4295         /**
4296          * Get the revision ID of the next revision
4297          *
4298          * @param int $revId Revision ID. Get the revision that was after this one.
4299          * @param int $flags Title::GAID_FOR_UPDATE
4300          * @return Int|Bool Next revision ID, or FALSE if none exists
4301          */
4302         public function getNextRevisionID( $revId, $flags = 0 ) {
4303                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4304                 $revId = $db->selectField( 'revision', 'rev_id',
4305                         array(
4306                                 'rev_page' => $this->getArticleID( $flags ),
4307                                 'rev_id > ' . intval( $revId )
4308                         ),
4309                         __METHOD__,
4310                         array( 'ORDER BY' => 'rev_id' )
4311                 );
4312
4313                 if ( $revId === false ) {
4314                         return false;
4315                 } else {
4316                         return intval( $revId );
4317                 }
4318         }
4319
4320         /**
4321          * Get the first revision of the page
4322          *
4323          * @param int $flags Title::GAID_FOR_UPDATE
4324          * @return Revision|Null if page doesn't exist
4325          */
4326         public function getFirstRevision( $flags = 0 ) {
4327                 $pageId = $this->getArticleID( $flags );
4328                 if ( $pageId ) {
4329                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4330                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4331                                 array( 'rev_page' => $pageId ),
4332                                 __METHOD__,
4333                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4334                         );
4335                         if ( $row ) {
4336                                 return new Revision( $row );
4337                         }
4338                 }
4339                 return null;
4340         }
4341
4342         /**
4343          * Get the oldest revision timestamp of this page
4344          *
4345          * @param int $flags Title::GAID_FOR_UPDATE
4346          * @return String: MW timestamp
4347          */
4348         public function getEarliestRevTime( $flags = 0 ) {
4349                 $rev = $this->getFirstRevision( $flags );
4350                 return $rev ? $rev->getTimestamp() : null;
4351         }
4352
4353         /**
4354          * Check if this is a new page
4355          *
4356          * @return bool
4357          */
4358         public function isNewPage() {
4359                 $dbr = wfGetDB( DB_SLAVE );
4360                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4361         }
4362
4363         /**
4364          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4365          *
4366          * @return bool
4367          */
4368         public function isBigDeletion() {
4369                 global $wgDeleteRevisionsLimit;
4370
4371                 if ( !$wgDeleteRevisionsLimit ) {
4372                         return false;
4373                 }
4374
4375                 $revCount = $this->estimateRevisionCount();
4376                 return $revCount > $wgDeleteRevisionsLimit;
4377         }
4378
4379         /**
4380          * Get the  approximate revision count of this page.
4381          *
4382          * @return int
4383          */
4384         public function estimateRevisionCount() {
4385                 if ( !$this->exists() ) {
4386                         return 0;
4387                 }
4388
4389                 if ( $this->mEstimateRevisions === null ) {
4390                         $dbr = wfGetDB( DB_SLAVE );
4391                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4392                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4393                 }
4394
4395                 return $this->mEstimateRevisions;
4396         }
4397
4398         /**
4399          * Get the number of revisions between the given revision.
4400          * Used for diffs and other things that really need it.
4401          *
4402          * @param int|Revision $old Old revision or rev ID (first before range)
4403          * @param int|Revision $new New revision or rev ID (first after range)
4404          * @return Int Number of revisions between these revisions.
4405          */
4406         public function countRevisionsBetween( $old, $new ) {
4407                 if ( !( $old instanceof Revision ) ) {
4408                         $old = Revision::newFromTitle( $this, (int)$old );
4409                 }
4410                 if ( !( $new instanceof Revision ) ) {
4411                         $new = Revision::newFromTitle( $this, (int)$new );
4412                 }
4413                 if ( !$old || !$new ) {
4414                         return 0; // nothing to compare
4415                 }
4416                 $dbr = wfGetDB( DB_SLAVE );
4417                 return (int)$dbr->selectField( 'revision', 'count(*)',
4418                         array(
4419                                 'rev_page' => $this->getArticleID(),
4420                                 'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4421                                 'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4422                         ),
4423                         __METHOD__
4424                 );
4425         }
4426
4427         /**
4428          * Get the number of authors between the given revisions or revision IDs.
4429          * Used for diffs and other things that really need it.
4430          *
4431          * @param int|Revision $old Old revision or rev ID (first before range by default)
4432          * @param int|Revision $new New revision or rev ID (first after range by default)
4433          * @param int $limit Maximum number of authors
4434          * @param string|array $options (Optional): Single option, or an array of options:
4435          *     'include_old' Include $old in the range; $new is excluded.
4436          *     'include_new' Include $new in the range; $old is excluded.
4437          *     'include_both' Include both $old and $new in the range.
4438          *     Unknown option values are ignored.
4439          * @return int Number of revision authors in the range; zero if not both revisions exist
4440          */
4441         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4442                 if ( !( $old instanceof Revision ) ) {
4443                         $old = Revision::newFromTitle( $this, (int)$old );
4444                 }
4445                 if ( !( $new instanceof Revision ) ) {
4446                         $new = Revision::newFromTitle( $this, (int)$new );
4447                 }
4448                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4449                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4450                 // in the sanity check below?
4451                 if ( !$old || !$new ) {
4452                         return 0; // nothing to compare
4453                 }
4454                 $old_cmp = '>';
4455                 $new_cmp = '<';
4456                 $options = (array)$options;
4457                 if ( in_array( 'include_old', $options ) ) {
4458                         $old_cmp = '>=';
4459                 }
4460                 if ( in_array( 'include_new', $options ) ) {
4461                         $new_cmp = '<=';
4462                 }
4463                 if ( in_array( 'include_both', $options ) ) {
4464                         $old_cmp = '>=';
4465                         $new_cmp = '<=';
4466                 }
4467                 // No DB query needed if $old and $new are the same or successive revisions:
4468                 if ( $old->getId() === $new->getId() ) {
4469                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4470                 } elseif ( $old->getId() === $new->getParentId() ) {
4471                         if ( $old_cmp === '>' || $new_cmp === '<' ) {
4472                                 return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4473                         }
4474                         return ( $old->getRawUserText() === $new->getRawUserText() ) ? 1 : 2;
4475                 }
4476                 $dbr = wfGetDB( DB_SLAVE );
4477                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4478                         array(
4479                                 'rev_page' => $this->getArticleID(),
4480                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4481                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4482                         ), __METHOD__,
4483                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4484                 );
4485                 return (int)$dbr->numRows( $res );
4486         }
4487
4488         /**
4489          * Compare with another title.
4490          *
4491          * @param $title Title
4492          * @return Bool
4493          */
4494         public function equals( Title $title ) {
4495                 // Note: === is necessary for proper matching of number-like titles.
4496                 return $this->getInterwiki() === $title->getInterwiki()
4497                         && $this->getNamespace() == $title->getNamespace()
4498                         && $this->getDBkey() === $title->getDBkey();
4499         }
4500
4501         /**
4502          * Check if this title is a subpage of another title
4503          *
4504          * @param $title Title
4505          * @return Bool
4506          */
4507         public function isSubpageOf( Title $title ) {
4508                 return $this->getInterwiki() === $title->getInterwiki()
4509                         && $this->getNamespace() == $title->getNamespace()
4510                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4511         }
4512
4513         /**
4514          * Check if page exists.  For historical reasons, this function simply
4515          * checks for the existence of the title in the page table, and will
4516          * thus return false for interwiki links, special pages and the like.
4517          * If you want to know if a title can be meaningfully viewed, you should
4518          * probably call the isKnown() method instead.
4519          *
4520          * @return Bool
4521          */
4522         public function exists() {
4523                 return $this->getArticleID() != 0;
4524         }
4525
4526         /**
4527          * Should links to this title be shown as potentially viewable (i.e. as
4528          * "bluelinks"), even if there's no record by this title in the page
4529          * table?
4530          *
4531          * This function is semi-deprecated for public use, as well as somewhat
4532          * misleadingly named.  You probably just want to call isKnown(), which
4533          * calls this function internally.
4534          *
4535          * (ISSUE: Most of these checks are cheap, but the file existence check
4536          * can potentially be quite expensive.  Including it here fixes a lot of
4537          * existing code, but we might want to add an optional parameter to skip
4538          * it and any other expensive checks.)
4539          *
4540          * @return Bool
4541          */
4542         public function isAlwaysKnown() {
4543                 $isKnown = null;
4544
4545                 /**
4546                  * Allows overriding default behavior for determining if a page exists.
4547                  * If $isKnown is kept as null, regular checks happen. If it's
4548                  * a boolean, this value is returned by the isKnown method.
4549                  *
4550                  * @since 1.20
4551                  *
4552                  * @param Title $title
4553                  * @param boolean|null $isKnown
4554                  */
4555                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4556
4557                 if ( !is_null( $isKnown ) ) {
4558                         return $isKnown;
4559                 }
4560
4561                 if ( $this->isExternal() ) {
4562                         return true;  // any interwiki link might be viewable, for all we know
4563                 }
4564
4565                 switch ( $this->mNamespace ) {
4566                         case NS_MEDIA:
4567                         case NS_FILE:
4568                                 // file exists, possibly in a foreign repo
4569                                 return (bool)wfFindFile( $this );
4570                         case NS_SPECIAL:
4571                                 // valid special page
4572                                 return SpecialPageFactory::exists( $this->getDBkey() );
4573                         case NS_MAIN:
4574                                 // selflink, possibly with fragment
4575                                 return $this->mDbkeyform == '';
4576                         case NS_MEDIAWIKI:
4577                                 // known system message
4578                                 return $this->hasSourceText() !== false;
4579                         default:
4580                                 return false;
4581                 }
4582         }
4583
4584         /**
4585          * Does this title refer to a page that can (or might) be meaningfully
4586          * viewed?  In particular, this function may be used to determine if
4587          * links to the title should be rendered as "bluelinks" (as opposed to
4588          * "redlinks" to non-existent pages).
4589          * Adding something else to this function will cause inconsistency
4590          * since LinkHolderArray calls isAlwaysKnown() and does its own
4591          * page existence check.
4592          *
4593          * @return Bool
4594          */
4595         public function isKnown() {
4596                 return $this->isAlwaysKnown() || $this->exists();
4597         }
4598
4599         /**
4600          * Does this page have source text?
4601          *
4602          * @return Boolean
4603          */
4604         public function hasSourceText() {
4605                 if ( $this->exists() ) {
4606                         return true;
4607                 }
4608
4609                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4610                         // If the page doesn't exist but is a known system message, default
4611                         // message content will be displayed, same for language subpages-
4612                         // Use always content language to avoid loading hundreds of languages
4613                         // to get the link color.
4614                         global $wgContLang;
4615                         list( $name, ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4616                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4617                         return $message->exists();
4618                 }
4619
4620                 return false;
4621         }
4622
4623         /**
4624          * Get the default message text or false if the message doesn't exist
4625          *
4626          * @return String or false
4627          */
4628         public function getDefaultMessageText() {
4629                 global $wgContLang;
4630
4631                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4632                         return false;
4633                 }
4634
4635                 list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4636                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4637
4638                 if ( $message->exists() ) {
4639                         return $message->plain();
4640                 } else {
4641                         return false;
4642                 }
4643         }
4644
4645         /**
4646          * Updates page_touched for this page; called from LinksUpdate.php
4647          *
4648          * @return Bool true if the update succeeded
4649          */
4650         public function invalidateCache() {
4651                 if ( wfReadOnly() ) {
4652                         return false;
4653                 }
4654
4655                 $method = __METHOD__;
4656                 $dbw = wfGetDB( DB_MASTER );
4657                 $conds = $this->pageCond();
4658                 $dbw->onTransactionIdle( function() use ( $dbw, $conds, $method ) {
4659                         $dbw->update(
4660                                 'page',
4661                                 array( 'page_touched' => $dbw->timestamp() ),
4662                                 $conds,
4663                                 $method
4664                         );
4665                 } );
4666
4667                 return true;
4668         }
4669
4670         /**
4671          * Update page_touched timestamps and send squid purge messages for
4672          * pages linking to this title. May be sent to the job queue depending
4673          * on the number of links. Typically called on create and delete.
4674          */
4675         public function touchLinks() {
4676                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4677                 $u->doUpdate();
4678
4679                 if ( $this->getNamespace() == NS_CATEGORY ) {
4680                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4681                         $u->doUpdate();
4682                 }
4683         }
4684
4685         /**
4686          * Get the last touched timestamp
4687          *
4688          * @param $db DatabaseBase: optional db
4689          * @return String last-touched timestamp
4690          */
4691         public function getTouched( $db = null ) {
4692                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
4693                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4694                 return $touched;
4695         }
4696
4697         /**
4698          * Get the timestamp when this page was updated since the user last saw it.
4699          *
4700          * @param $user User
4701          * @return String|Null
4702          */
4703         public function getNotificationTimestamp( $user = null ) {
4704                 global $wgUser, $wgShowUpdatedMarker;
4705                 // Assume current user if none given
4706                 if ( !$user ) {
4707                         $user = $wgUser;
4708                 }
4709                 // Check cache first
4710                 $uid = $user->getId();
4711                 // avoid isset here, as it'll return false for null entries
4712                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4713                         return $this->mNotificationTimestamp[$uid];
4714                 }
4715                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4716                         $this->mNotificationTimestamp[$uid] = false;
4717                         return $this->mNotificationTimestamp[$uid];
4718                 }
4719                 // Don't cache too much!
4720                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4721                         $this->mNotificationTimestamp = array();
4722                 }
4723                 $dbr = wfGetDB( DB_SLAVE );
4724                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4725                         'wl_notificationtimestamp',
4726                         array(
4727                                 'wl_user' => $user->getId(),
4728                                 'wl_namespace' => $this->getNamespace(),
4729                                 'wl_title' => $this->getDBkey(),
4730                         ),
4731                         __METHOD__
4732                 );
4733                 return $this->mNotificationTimestamp[$uid];
4734         }
4735
4736         /**
4737          * Generate strings used for xml 'id' names in monobook tabs
4738          *
4739          * @param string $prepend defaults to 'nstab-'
4740          * @return String XML 'id' name
4741          */
4742         public function getNamespaceKey( $prepend = 'nstab-' ) {
4743                 global $wgContLang;
4744                 // Gets the subject namespace if this title
4745                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4746                 // Checks if canonical namespace name exists for namespace
4747                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4748                         // Uses canonical namespace name
4749                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4750                 } else {
4751                         // Uses text of namespace
4752                         $namespaceKey = $this->getSubjectNsText();
4753                 }
4754                 // Makes namespace key lowercase
4755                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4756                 // Uses main
4757                 if ( $namespaceKey == '' ) {
4758                         $namespaceKey = 'main';
4759                 }
4760                 // Changes file to image for backwards compatibility
4761                 if ( $namespaceKey == 'file' ) {
4762                         $namespaceKey = 'image';
4763                 }
4764                 return $prepend . $namespaceKey;
4765         }
4766
4767         /**
4768          * Get all extant redirects to this Title
4769          *
4770          * @param int|Null $ns Single namespace to consider; NULL to consider all namespaces
4771          * @return Title[] Array of Title redirects to this title
4772          */
4773         public function getRedirectsHere( $ns = null ) {
4774                 $redirs = array();
4775
4776                 $dbr = wfGetDB( DB_SLAVE );
4777                 $where = array(
4778                         'rd_namespace' => $this->getNamespace(),
4779                         'rd_title' => $this->getDBkey(),
4780                         'rd_from = page_id'
4781                 );
4782                 if ( $this->isExternal() ) {
4783                         $where['rd_interwiki'] = $this->getInterwiki();
4784                 } else {
4785                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4786                 }
4787                 if ( !is_null( $ns ) ) {
4788                         $where['page_namespace'] = $ns;
4789                 }
4790
4791                 $res = $dbr->select(
4792                         array( 'redirect', 'page' ),
4793                         array( 'page_namespace', 'page_title' ),
4794                         $where,
4795                         __METHOD__
4796                 );
4797
4798                 foreach ( $res as $row ) {
4799                         $redirs[] = self::newFromRow( $row );
4800                 }
4801                 return $redirs;
4802         }
4803
4804         /**
4805          * Check if this Title is a valid redirect target
4806          *
4807          * @return Bool
4808          */
4809         public function isValidRedirectTarget() {
4810                 global $wgInvalidRedirectTargets;
4811
4812                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4813                 if ( $this->isSpecial( 'Userlogout' ) ) {
4814                         return false;
4815                 }
4816
4817                 foreach ( $wgInvalidRedirectTargets as $target ) {
4818                         if ( $this->isSpecial( $target ) ) {
4819                                 return false;
4820                         }
4821                 }
4822
4823                 return true;
4824         }
4825
4826         /**
4827          * Get a backlink cache object
4828          *
4829          * @return BacklinkCache
4830          */
4831         public function getBacklinkCache() {
4832                 return BacklinkCache::get( $this );
4833         }
4834
4835         /**
4836          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4837          *
4838          * @return Boolean
4839          */
4840         public function canUseNoindex() {
4841                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4842
4843                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4844                         ? $wgContentNamespaces
4845                         : $wgExemptFromUserRobotsControl;
4846
4847                 return !in_array( $this->mNamespace, $bannedNamespaces );
4848
4849         }
4850
4851         /**
4852          * Returns the raw sort key to be used for categories, with the specified
4853          * prefix.  This will be fed to Collation::getSortKey() to get a
4854          * binary sortkey that can be used for actual sorting.
4855          *
4856          * @param string $prefix The prefix to be used, specified using
4857          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4858          *   prefix.
4859          * @return string
4860          */
4861         public function getCategorySortkey( $prefix = '' ) {
4862                 $unprefixed = $this->getText();
4863
4864                 // Anything that uses this hook should only depend
4865                 // on the Title object passed in, and should probably
4866                 // tell the users to run updateCollations.php --force
4867                 // in order to re-sort existing category relations.
4868                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4869                 if ( $prefix !== '' ) {
4870                         # Separate with a line feed, so the unprefixed part is only used as
4871                         # a tiebreaker when two pages have the exact same prefix.
4872                         # In UCA, tab is the only character that can sort above LF
4873                         # so we strip both of them from the original prefix.
4874                         $prefix = strtr( $prefix, "\n\t", '  ' );
4875                         return "$prefix\n$unprefixed";
4876                 }
4877                 return $unprefixed;
4878         }
4879
4880         /**
4881          * Get the language in which the content of this page is written in
4882          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4883          * e.g. $wgLang (such as special pages, which are in the user language).
4884          *
4885          * @since 1.18
4886          * @return Language
4887          */
4888         public function getPageLanguage() {
4889                 global $wgLang, $wgLanguageCode;
4890                 wfProfileIn( __METHOD__ );
4891                 if ( $this->isSpecialPage() ) {
4892                         // special pages are in the user language
4893                         wfProfileOut( __METHOD__ );
4894                         return $wgLang;
4895                 }
4896
4897                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4898                         // Note that this may depend on user settings, so the cache should be only per-request.
4899                         // NOTE: ContentHandler::getPageLanguage() may need to load the content to determine the page language!
4900                         // Checking $wgLanguageCode hasn't changed for the benefit of unit tests.
4901                         $contentHandler = ContentHandler::getForTitle( $this );
4902                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4903                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4904                 } else {
4905                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4906                 }
4907                 wfProfileOut( __METHOD__ );
4908                 return $langObj;
4909         }
4910
4911         /**
4912          * Get the language in which the content of this page is written when
4913          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4914          * e.g. $wgLang (such as special pages, which are in the user language).
4915          *
4916          * @since 1.20
4917          * @return Language
4918          */
4919         public function getPageViewLanguage() {
4920                 global $wgLang;
4921
4922                 if ( $this->isSpecialPage() ) {
4923                         // If the user chooses a variant, the content is actually
4924                         // in a language whose code is the variant code.
4925                         $variant = $wgLang->getPreferredVariant();
4926                         if ( $wgLang->getCode() !== $variant ) {
4927                                 return Language::factory( $variant );
4928                         }
4929
4930                         return $wgLang;
4931                 }
4932
4933                 //NOTE: can't be cached persistently, depends on user settings
4934                 //NOTE: ContentHandler::getPageViewLanguage() may need to load the content to determine the page language!
4935                 $contentHandler = ContentHandler::getForTitle( $this );
4936                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4937                 return $pageLang;
4938         }
4939
4940         /**
4941          * Get a list of rendered edit notices for this page.
4942          *
4943          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4944          * they will already be wrapped in paragraphs.
4945          *
4946          * @since 1.21
4947          * @param int oldid Revision ID that's being edited
4948          * @return Array
4949          */
4950         public function getEditNotices( $oldid = 0 ) {
4951                 $notices = array();
4952
4953                 # Optional notices on a per-namespace and per-page basis
4954                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4955                 $editnotice_ns_message = wfMessage( $editnotice_ns );
4956                 if ( $editnotice_ns_message->exists() ) {
4957                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
4958                 }
4959                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4960                         $parts = explode( '/', $this->getDBkey() );
4961                         $editnotice_base = $editnotice_ns;
4962                         while ( count( $parts ) > 0 ) {
4963                                 $editnotice_base .= '-' . array_shift( $parts );
4964                                 $editnotice_base_msg = wfMessage( $editnotice_base );
4965                                 if ( $editnotice_base_msg->exists() ) {
4966                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
4967                                 }
4968                         }
4969                 } else {
4970                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
4971                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
4972                         $editnoticeMsg = wfMessage( $editnoticeText );
4973                         if ( $editnoticeMsg->exists() ) {
4974                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
4975                         }
4976                 }
4977
4978                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4979                 return $notices;
4980         }
4981 }