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