includes/Title.php

   1 <?php
   2 /**
   3  * Representation a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 /**
  26  * Represents a title within MediaWiki.
  27  * Optionally may contain an interwiki designation or namespace.
  28  * @note This class can fetch various kinds of data from the database;
  29  *       however, it does so inefficiently.
  30  *
  31  * @internal documentation reviewed 15 Mar 2010
  32  */
  33 class Title {
  34         /** @var MapCacheLRU */
  35         static private $titleCache = null;
  36
  37         /**
  38          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  39          * commonly used titles. On a batch operation this can become a memory leak
  40          * if not bounded. After hitting this many titles reset the cache.
  41          */
  42         const CACHE_MAX = 1000;
  43
  44         /**
  45          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  46          * to use the master DB
  47          */
  48         const GAID_FOR_UPDATE = 1;
  49
  50         /**
  51          * @name Private member variables
  52          * Please use the accessor functions instead.
  53          * @private
  54          */
  55         // @{
  56
  57         var $mTextform = '';              // /< Text form (spaces not underscores) of the main part
  58         var $mUrlform = '';               // /< URL-encoded form of the main part
  59         var $mDbkeyform = '';             // /< Main part with underscores
  60         var $mUserCaseDBKey;              // /< DB key with the initial letter in the case specified by the user
  61         var $mNamespace = NS_MAIN;        // /< Namespace index, i.e. one of the NS_xxxx constants
  62         var $mInterwiki = '';             // /< Interwiki prefix
  63         var $mFragment = '';              // /< Title fragment (i.e. the bit after the #)
  64         var $mArticleID = -1;             // /< Article ID, fetched from the link cache on demand
  65         var $mLatestID = false;           // /< ID of most recent revision
  66         var $mContentModel = false;       // /< ID of the page's content model, i.e. one of the CONTENT_MODEL_XXX constants
  67         private $mEstimateRevisions;      // /< Estimated number of revisions; null of not loaded
  68         var $mRestrictions = array();     // /< Array of groups allowed to edit this article
  69         var $mOldRestrictions = false;
  70         var $mCascadeRestriction;         ///< Cascade restrictions on this page to included templates and images?
  71         var $mCascadingRestrictions;      // Caching the results of getCascadeProtectionSources
  72         var $mRestrictionsExpiry = array(); ///< When do the restrictions on this page expire?
  73         var $mHasCascadingRestrictions;   ///< Are cascading restrictions in effect on this page?
  74         var $mCascadeSources;             ///< Where are the cascading restrictions coming from on this page?
  75         var $mRestrictionsLoaded = false; ///< Boolean for initialisation on demand
  76         var $mPrefixedText = null;        ///< Text form including namespace/interwiki, initialised on demand
  77         var $mTitleProtection;            ///< Cached value for getTitleProtection (create protection)
  78         # Don't change the following default, NS_MAIN is hardcoded in several
  79         # places.  See bug 696.
  80         # Zero except in {{transclusion}} tags
  81         var $mDefaultNamespace = NS_MAIN; // /< Namespace index when there is no namespace
  82         var $mWatched = null;             // /< Is $wgUser watching this page? null if unfilled, accessed through userIsWatching()
  83         var $mLength = -1;                // /< The page length, 0 for special pages
  84         var $mRedirect = null;            // /< Is the article at this title a redirect?
  85         var $mNotificationTimestamp = array(); // /< Associative array of user ID -> timestamp/false
  86         var $mHasSubpage;                 // /< Whether a page has any subpages
  87         private $mPageLanguage = false;   // /< The (string) language code of the page's language and content code.
  88         // @}
  89
  90         /**
  91          * Constructor
  92          */
  93         /*protected*/ function __construct() { }
  94
  95         /**
  96          * Create a new Title from a prefixed DB key
  97          *
  98          * @param string $key the database key, which has underscores
  99          *      instead of spaces, possibly including namespace and
 100          *      interwiki prefixes
 101          * @return Title, or NULL on an error
 102          */
 103         public static function newFromDBkey( $key ) {
 104                 $t = new Title();
 105                 $t->mDbkeyform = $key;
 106                 if ( $t->secureAndSplit() ) {
 107                         return $t;
 108                 } else {
 109                         return null;
 110                 }
 111         }
 112
 113         /**
 114          * Create a new Title from text, such as what one would find in a link. De-
 115          * codes any HTML entities in the text.
 116          *
 117          * @param string $text the link text; spaces, prefixes, and an
 118          *   initial ':' indicating the main namespace are accepted.
 119          * @param int $defaultNamespace the namespace to use if none is specified
 120          *   by a prefix.  If you want to force a specific namespace even if
 121          *   $text might begin with a namespace prefix, use makeTitle() or
 122          *   makeTitleSafe().
 123          * @throws MWException
 124          * @return Title|null - Title or null on an error.
 125          */
 126         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 127                 if ( is_object( $text ) ) {
 128                         throw new MWException( 'Title::newFromText given an object' );
 129                 }
 130
 131                 $cache = self::getTitleCache();
 132
 133                 /**
 134                  * Wiki pages often contain multiple links to the same page.
 135                  * Title normalization and parsing can become expensive on
 136                  * pages with many links, so we can save a little time by
 137                  * caching them.
 138                  *
 139                  * In theory these are value objects and won't get changed...
 140                  */
 141                 if ( $defaultNamespace == NS_MAIN && $cache->has( $text ) ) {
 142                         return $cache->get( $text );
 143                 }
 144
 145                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 146                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 147
 148                 $t = new Title();
 149                 $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
 150                 $t->mDefaultNamespace = $defaultNamespace;
 151
 152                 if ( $t->secureAndSplit() ) {
 153                         if ( $defaultNamespace == NS_MAIN ) {
 154                                 $cache->set( $text, $t );
 155                         }
 156                         return $t;
 157                 } else {
 158                         $ret = null;
 159                         return $ret;
 160                 }
 161         }
 162
 163         /**
 164          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 165          *
 166          * Example of wrong and broken code:
 167          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 168          *
 169          * Example of right code:
 170          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 171          *
 172          * Create a new Title from URL-encoded text. Ensures that
 173          * the given title's length does not exceed the maximum.
 174          *
 175          * @param string $url the title, as might be taken from a URL
 176          * @return Title the new object, or NULL on an error
 177          */
 178         public static function newFromURL( $url ) {
 179                 $t = new Title();
 180
 181                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 182                 # but some URLs used it as a space replacement and they still come
 183                 # from some external search tools.
 184                 if ( strpos( self::legalChars(), '+' ) === false ) {
 185                         $url = str_replace( '+', ' ', $url );
 186                 }
 187
 188                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 189                 if ( $t->secureAndSplit() ) {
 190                         return $t;
 191                 } else {
 192                         return null;
 193                 }
 194         }
 195
 196         /**
 197          * @return MapCacheLRU
 198          */
 199         private static function getTitleCache() {
 200                 if ( self::$titleCache == null ) {
 201                         self::$titleCache = new MapCacheLRU( self::CACHE_MAX );
 202                 }
 203                 return self::$titleCache;
 204         }
 205
 206         /**
 207          * Returns a list of fields that are to be selected for initializing Title objects or LinkCache entries.
 208          * Uses $wgContentHandlerUseDB to determine whether to include page_content_model.
 209          *
 210          * @return array
 211          */
 212         protected static function getSelectFields() {
 213                 global $wgContentHandlerUseDB;
 214
 215                 $fields = array(
 216                         'page_namespace', 'page_title', 'page_id',
 217                         'page_len', 'page_is_redirect', 'page_latest',
 218                 );
 219
 220                 if ( $wgContentHandlerUseDB ) {
 221                         $fields[] = 'page_content_model';
 222                 }
 223
 224                 return $fields;
 225         }
 226
 227         /**
 228          * Create a new Title from an article ID
 229          *
 230          * @param int $id the page_id corresponding to the Title to create
 231          * @param int $flags use Title::GAID_FOR_UPDATE to use master
 232          * @return Title|null the new object, or NULL on an error
 233          */
 234         public static function newFromID( $id, $flags = 0 ) {
 235                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 236                 $row = $db->selectRow(
 237                         'page',
 238                         self::getSelectFields(),
 239                         array( 'page_id' => $id ),
 240                         __METHOD__
 241                 );
 242                 if ( $row !== false ) {
 243                         $title = Title::newFromRow( $row );
 244                 } else {
 245                         $title = null;
 246                 }
 247                 return $title;
 248         }
 249
 250         /**
 251          * Make an array of titles from an array of IDs
 252          *
 253          * @param array $ids of Int Array of IDs
 254          * @return Array of Titles
 255          */
 256         public static function newFromIDs( $ids ) {
 257                 if ( !count( $ids ) ) {
 258                         return array();
 259                 }
 260                 $dbr = wfGetDB( DB_SLAVE );
 261
 262                 $res = $dbr->select(
 263                         'page',
 264                         self::getSelectFields(),
 265                         array( 'page_id' => $ids ),
 266                         __METHOD__
 267                 );
 268
 269                 $titles = array();
 270                 foreach ( $res as $row ) {
 271                         $titles[] = Title::newFromRow( $row );
 272                 }
 273                 return $titles;
 274         }
 275
 276         /**
 277          * Make a Title object from a DB row
 278          *
 279          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 280          * @return Title corresponding Title
 281          */
 282         public static function newFromRow( $row ) {
 283                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 284                 $t->loadFromRow( $row );
 285                 return $t;
 286         }
 287
 288         /**
 289          * Load Title object fields from a DB row.
 290          * If false is given, the title will be treated as non-existing.
 291          *
 292          * @param $row stdClass|bool database row
 293          */
 294         public function loadFromRow( $row ) {
 295                 if ( $row ) { // page found
 296                         if ( isset( $row->page_id ) ) {
 297                                 $this->mArticleID = (int)$row->page_id;
 298                         }
 299                         if ( isset( $row->page_len ) ) {
 300                                 $this->mLength = (int)$row->page_len;
 301                         }
 302                         if ( isset( $row->page_is_redirect ) ) {
 303                                 $this->mRedirect = (bool)$row->page_is_redirect;
 304                         }
 305                         if ( isset( $row->page_latest ) ) {
 306                                 $this->mLatestID = (int)$row->page_latest;
 307                         }
 308                         if ( isset( $row->page_content_model ) ) {
 309                                 $this->mContentModel = strval( $row->page_content_model );
 310                         } else {
 311                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 312                         }
 313                 } else { // page not found
 314                         $this->mArticleID = 0;
 315                         $this->mLength = 0;
 316                         $this->mRedirect = false;
 317                         $this->mLatestID = 0;
 318                         $this->mContentModel = false; # initialized lazily in getContentModel()
 319                 }
 320         }
 321
 322         /**
 323          * Create a new Title from a namespace index and a DB key.
 324          * It's assumed that $ns and $title are *valid*, for instance when
 325          * they came directly from the database or a special page name.
 326          * For convenience, spaces are converted to underscores so that
 327          * eg user_text fields can be used directly.
 328          *
 329          * @param int $ns the namespace of the article
 330          * @param string $title the unprefixed database key form
 331          * @param string $fragment the link fragment (after the "#")
 332          * @param string $interwiki the interwiki prefix
 333          * @return Title the new object
 334          */
 335         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 336                 $t = new Title();
 337                 $t->mInterwiki = $interwiki;
 338                 $t->mFragment = $fragment;
 339                 $t->mNamespace = $ns = intval( $ns );
 340                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 341                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 342                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 343                 $t->mTextform = str_replace( '_', ' ', $title );
 344                 $t->mContentModel = false; # initialized lazily in getContentModel()
 345                 return $t;
 346         }
 347
 348         /**
 349          * Create a new Title from a namespace index and a DB key.
 350          * The parameters will be checked for validity, which is a bit slower
 351          * than makeTitle() but safer for user-provided data.
 352          *
 353          * @param int $ns the namespace of the article
 354          * @param string $title database key form
 355          * @param string $fragment the link fragment (after the "#")
 356          * @param string $interwiki interwiki prefix
 357          * @return Title the new object, or NULL on an error
 358          */
 359         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 360                 if ( !MWNamespace::exists( $ns ) ) {
 361                         return null;
 362                 }
 363
 364                 $t = new Title();
 365                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 366                 if ( $t->secureAndSplit() ) {
 367                         return $t;
 368                 } else {
 369                         return null;
 370                 }
 371         }
 372
 373         /**
 374          * Create a new Title for the Main Page
 375          *
 376          * @return Title the new object
 377          */
 378         public static function newMainPage() {
 379                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 380                 // Don't give fatal errors if the message is broken
 381                 if ( !$title ) {
 382                         $title = Title::newFromText( 'Main Page' );
 383                 }
 384                 return $title;
 385         }
 386
 387         /**
 388          * Extract a redirect destination from a string and return the
 389          * Title, or null if the text doesn't contain a valid redirect
 390          * This will only return the very next target, useful for
 391          * the redirect table and other checks that don't need full recursion
 392          *
 393          * @param string $text Text with possible redirect
 394          * @return Title: The corresponding Title
 395          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 396          */
 397         public static function newFromRedirect( $text ) {
 398                 ContentHandler::deprecated( __METHOD__, '1.21' );
 399
 400                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 401                 return $content->getRedirectTarget();
 402         }
 403
 404         /**
 405          * Extract a redirect destination from a string and return the
 406          * Title, or null if the text doesn't contain a valid redirect
 407          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 408          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 409          *
 410          * @param string $text Text with possible redirect
 411          * @return Title
 412          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 413          */
 414         public static function newFromRedirectRecurse( $text ) {
 415                 ContentHandler::deprecated( __METHOD__, '1.21' );
 416
 417                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 418                 return $content->getUltimateRedirectTarget();
 419         }
 420
 421         /**
 422          * Extract a redirect destination from a string and return an
 423          * array of Titles, or null if the text doesn't contain a valid redirect
 424          * The last element in the array is the final destination after all redirects
 425          * have been resolved (up to $wgMaxRedirects times)
 426          *
 427          * @param string $text Text with possible redirect
 428          * @return Array of Titles, with the destination last
 429          * @deprecated since 1.21, use Content::getRedirectChain instead.
 430          */
 431         public static function newFromRedirectArray( $text ) {
 432                 ContentHandler::deprecated( __METHOD__, '1.21' );
 433
 434                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 435                 return $content->getRedirectChain();
 436         }
 437
 438         /**
 439          * Get the prefixed DB key associated with an ID
 440          *
 441          * @param int $id the page_id of the article
 442          * @return Title an object representing the article, or NULL if no such article was found
 443          */
 444         public static function nameOf( $id ) {
 445                 $dbr = wfGetDB( DB_SLAVE );
 446
 447                 $s = $dbr->selectRow(
 448                         'page',
 449                         array( 'page_namespace', 'page_title' ),
 450                         array( 'page_id' => $id ),
 451                         __METHOD__
 452                 );
 453                 if ( $s === false ) {
 454                         return null;
 455                 }
 456
 457                 $n = self::makeName( $s->page_namespace, $s->page_title );
 458                 return $n;
 459         }
 460
 461         /**
 462          * Get a regex character class describing the legal characters in a link
 463          *
 464          * @return String the list of characters, not delimited
 465          */
 466         public static function legalChars() {
 467                 global $wgLegalTitleChars;
 468                 return $wgLegalTitleChars;
 469         }
 470
 471         /**
 472          * Returns a simple regex that will match on characters and sequences invalid in titles.
 473          * Note that this doesn't pick up many things that could be wrong with titles, but that
 474          * replacing this regex with something valid will make many titles valid.
 475          *
 476          * @return String regex string
 477          */
 478         static function getTitleInvalidRegex() {
 479                 static $rxTc = false;
 480                 if ( !$rxTc ) {
 481                         # Matching titles will be held as illegal.
 482                         $rxTc = '/' .
 483                                 # Any character not allowed is forbidden...
 484                                 '[^' . self::legalChars() . ']' .
 485                                 # URL percent encoding sequences interfere with the ability
 486                                 # to round-trip titles -- you can't link to them consistently.
 487                                 '|%[0-9A-Fa-f]{2}' .
 488                                 # XML/HTML character references produce similar issues.
 489                                 '|&[A-Za-z0-9\x80-\xff]+;' .
 490                                 '|&#[0-9]+;' .
 491                                 '|&#x[0-9A-Fa-f]+;' .
 492                                 '/S';
 493                 }
 494
 495                 return $rxTc;
 496         }
 497
 498         /**
 499          * Utility method for converting a character sequence from bytes to Unicode.
 500          *
 501          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 502          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 503          *
 504          * @param string $byteClass
 505          * @return string
 506          */
 507         public static function convertByteClassToUnicodeClass( $byteClass ) {
 508                 $length = strlen( $byteClass );
 509                 // Input token queue
 510                 $x0 = $x1 = $x2 = '';
 511                 // Decoded queue
 512                 $d0 = $d1 = $d2 = '';
 513                 // Decoded integer codepoints
 514                 $ord0 = $ord1 = $ord2 = 0;
 515                 // Re-encoded queue
 516                 $r0 = $r1 = $r2 = '';
 517                 // Output
 518                 $out = '';
 519                 // Flags
 520                 $allowUnicode = false;
 521                 for ( $pos = 0; $pos < $length; $pos++ ) {
 522                         // Shift the queues down
 523                         $x2 = $x1;
 524                         $x1 = $x0;
 525                         $d2 = $d1;
 526                         $d1 = $d0;
 527                         $ord2 = $ord1;
 528                         $ord1 = $ord0;
 529                         $r2 = $r1;
 530                         $r1 = $r0;
 531                         // Load the current input token and decoded values
 532                         $inChar = $byteClass[$pos];
 533                         if ( $inChar == '\\' ) {
 534                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 535                                         $x0 = $inChar . $m[0];
 536                                         $d0 = chr( hexdec( $m[1] ) );
 537                                         $pos += strlen( $m[0] );
 538                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 539                                         $x0 = $inChar . $m[0];
 540                                         $d0 = chr( octdec( $m[0] ) );
 541                                         $pos += strlen( $m[0] );
 542                                 } elseif ( $pos + 1 >= $length ) {
 543                                         $x0 = $d0 = '\\';
 544                                 } else {
 545                                         $d0 = $byteClass[$pos + 1];
 546                                         $x0 = $inChar . $d0;
 547                                         $pos += 1;
 548                                 }
 549                         } else {
 550                                 $x0 = $d0 = $inChar;
 551                         }
 552                         $ord0 = ord( $d0 );
 553                         // Load the current re-encoded value
 554                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 555                                 $r0 = sprintf( '\x%02x', $ord0 );
 556                         } elseif ( $ord0 >= 0x80 ) {
 557                                 // Allow unicode if a single high-bit character appears
 558                                 $r0 = sprintf( '\x%02x', $ord0 );
 559                                 $allowUnicode = true;
 560                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 561                                 $r0 = '\\' . $d0;
 562                         } else {
 563                                 $r0 = $d0;
 564                         }
 565                         // Do the output
 566                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 567                                 // Range
 568                                 if ( $ord2 > $ord0 ) {
 569                                         // Empty range
 570                                 } elseif ( $ord0 >= 0x80 ) {
 571                                         // Unicode range
 572                                         $allowUnicode = true;
 573                                         if ( $ord2 < 0x80 ) {
 574                                                 // Keep the non-unicode section of the range
 575                                                 $out .= "$r2-\\x7F";
 576                                         }
 577                                 } else {
 578                                         // Normal range
 579                                         $out .= "$r2-$r0";
 580                                 }
 581                                 // Reset state to the initial value
 582                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 583                         } elseif ( $ord2 < 0x80 ) {
 584                                 // ASCII character
 585                                 $out .= $r2;
 586                         }
 587                 }
 588                 if ( $ord1 < 0x80 ) {
 589                         $out .= $r1;
 590                 }
 591                 if ( $ord0 < 0x80 ) {
 592                         $out .= $r0;
 593                 }
 594                 if ( $allowUnicode ) {
 595                         $out .= '\u0080-\uFFFF';
 596                 }
 597                 return $out;
 598         }
 599
 600         /**
 601          * Get a string representation of a title suitable for
 602          * including in a search index
 603          *
 604          * @param int $ns a namespace index
 605          * @param string $title text-form main part
 606          * @return String a stripped-down title string ready for the search index
 607          */
 608         public static function indexTitle( $ns, $title ) {
 609                 global $wgContLang;
 610
 611                 $lc = SearchEngine::legalSearchChars() . '&#;';
 612                 $t = $wgContLang->normalizeForSearch( $title );
 613                 $t = preg_replace( "/[^{$lc}]+/", ' ', $t );
 614                 $t = $wgContLang->lc( $t );
 615
 616                 # Handle 's, s'
 617                 $t = preg_replace( "/([{$lc}]+)'s( |$)/", "\\1 \\1's ", $t );
 618                 $t = preg_replace( "/([{$lc}]+)s'( |$)/", "\\1s ", $t );
 619
 620                 $t = preg_replace( "/\\s+/", ' ', $t );
 621
 622                 if ( $ns == NS_FILE ) {
 623                         $t = preg_replace( "/ (png|gif|jpg|jpeg|ogg)$/", "", $t );
 624                 }
 625                 return trim( $t );
 626         }
 627
 628         /**
 629          * Make a prefixed DB key from a DB key and a namespace index
 630          *
 631          * @param int $ns numerical representation of the namespace
 632          * @param string $title the DB key form the title
 633          * @param string $fragment The link fragment (after the "#")
 634          * @param string $interwiki The interwiki prefix
 635          * @return String the prefixed form of the title
 636          */
 637         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 638                 global $wgContLang;
 639
 640                 $namespace = $wgContLang->getNsText( $ns );
 641                 $name = $namespace == '' ? $title : "$namespace:$title";
 642                 if ( strval( $interwiki ) != '' ) {
 643                         $name = "$interwiki:$name";
 644                 }
 645                 if ( strval( $fragment ) != '' ) {
 646                         $name .= '#' . $fragment;
 647                 }
 648                 return $name;
 649         }
 650
 651         /**
 652          * Escape a text fragment, say from a link, for a URL
 653          *
 654          * @param string $fragment containing a URL or link fragment (after the "#")
 655          * @return String: escaped string
 656          */
 657         static function escapeFragmentForURL( $fragment ) {
 658                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 659                 # fragments appear not to work in IE (at least up to 7) or in at least
 660                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 661                 # to care if they aren't encoded.
 662                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 663         }
 664
 665         /**
 666          * Callback for usort() to do title sorts by (namespace, title)
 667          *
 668          * @param $a Title
 669          * @param $b Title
 670          *
 671          * @return Integer: result of string comparison, or namespace comparison
 672          */
 673         public static function compare( $a, $b ) {
 674                 if ( $a->getNamespace() == $b->getNamespace() ) {
 675                         return strcmp( $a->getText(), $b->getText() );
 676                 } else {
 677                         return $a->getNamespace() - $b->getNamespace();
 678                 }
 679         }
 680
 681         /**
 682          * Determine whether the object refers to a page within
 683          * this project.
 684          *
 685          * @return Bool TRUE if this is an in-project interwiki link or a wikilink, FALSE otherwise
 686          */
 687         public function isLocal() {
 688                 if ( $this->isExternal() ) {
 689                         $iw = Interwiki::fetch( $this->mInterwiki );
 690                         if ( $iw ) {
 691                                 return $iw->isLocal();
 692                         }
 693                 }
 694                 return true;
 695         }
 696
 697         /**
 698          * Is this Title interwiki?
 699          *
 700          * @return Bool
 701          */
 702         public function isExternal() {
 703                 return $this->mInterwiki !== '';
 704         }
 705
 706         /**
 707          * Get the interwiki prefix
 708          *
 709          * Use Title::isExternal to check if a interwiki is set
 710          *
 711          * @return String Interwiki prefix
 712          */
 713         public function getInterwiki() {
 714                 return $this->mInterwiki;
 715         }
 716
 717         /**
 718          * Determine whether the object refers to a page within
 719          * this project and is transcludable.
 720          *
 721          * @return Bool TRUE if this is transcludable
 722          */
 723         public function isTrans() {
 724                 if ( !$this->isExternal() ) {
 725                         return false;
 726                 }
 727
 728                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 729         }
 730
 731         /**
 732          * Returns the DB name of the distant wiki which owns the object.
 733          *
 734          * @return String the DB name
 735          */
 736         public function getTransWikiID() {
 737                 if ( !$this->isExternal() ) {
 738                         return false;
 739                 }
 740
 741                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 742         }
 743
 744         /**
 745          * Get the text form (spaces not underscores) of the main part
 746          *
 747          * @return String Main part of the title
 748          */
 749         public function getText() {
 750                 return $this->mTextform;
 751         }
 752
 753         /**
 754          * Get the URL-encoded form of the main part
 755          *
 756          * @return String Main part of the title, URL-encoded
 757          */
 758         public function getPartialURL() {
 759                 return $this->mUrlform;
 760         }
 761
 762         /**
 763          * Get the main part with underscores
 764          *
 765          * @return String: Main part of the title, with underscores
 766          */
 767         public function getDBkey() {
 768                 return $this->mDbkeyform;
 769         }
 770
 771         /**
 772          * Get the DB key with the initial letter case as specified by the user
 773          *
 774          * @return String DB key
 775          */
 776         function getUserCaseDBKey() {
 777                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 778                         return $this->mUserCaseDBKey;
 779                 } else {
 780                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 781                         return $this->mDbkeyform;
 782                 }
 783         }
 784
 785         /**
 786          * Get the namespace index, i.e. one of the NS_xxxx constants.
 787          *
 788          * @return Integer: Namespace index
 789          */
 790         public function getNamespace() {
 791                 return $this->mNamespace;
 792         }
 793
 794         /**
 795          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 796          *
 797          * @throws MWException
 798          * @return String: Content model id
 799          */
 800         public function getContentModel() {
 801                 if ( !$this->mContentModel ) {
 802                         $linkCache = LinkCache::singleton();
 803                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 804                 }
 805
 806                 if ( !$this->mContentModel ) {
 807                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 808                 }
 809
 810                 if ( !$this->mContentModel ) {
 811                         throw new MWException( 'Failed to determine content model!' );
 812                 }
 813
 814                 return $this->mContentModel;
 815         }
 816
 817         /**
 818          * Convenience method for checking a title's content model name
 819          *
 820          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 821          * @return Boolean true if $this->getContentModel() == $id
 822          */
 823         public function hasContentModel( $id ) {
 824                 return $this->getContentModel() == $id;
 825         }
 826
 827         /**
 828          * Get the namespace text
 829          *
 830          * @return String: Namespace text
 831          */
 832         public function getNsText() {
 833                 global $wgContLang;
 834
 835                 if ( $this->isExternal() ) {
 836                         // This probably shouldn't even happen. ohh man, oh yuck.
 837                         // But for interwiki transclusion it sometimes does.
 838                         // Shit. Shit shit shit.
 839                         //
 840                         // Use the canonical namespaces if possible to try to
 841                         // resolve a foreign namespace.
 842                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 843                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 844                         }
 845                 }
 846
 847                 if ( $wgContLang->needsGenderDistinction() &&
 848                                 MWNamespace::hasGenderDistinction( $this->mNamespace ) ) {
 849                         $gender = GenderCache::singleton()->getGenderOf( $this->getText(), __METHOD__ );
 850                         return $wgContLang->getGenderNsText( $this->mNamespace, $gender );
 851                 }
 852
 853                 return $wgContLang->getNsText( $this->mNamespace );
 854         }
 855
 856         /**
 857          * Get the namespace text of the subject (rather than talk) page
 858          *
 859          * @return String Namespace text
 860          */
 861         public function getSubjectNsText() {
 862                 global $wgContLang;
 863                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 864         }
 865
 866         /**
 867          * Get the namespace text of the talk page
 868          *
 869          * @return String Namespace text
 870          */
 871         public function getTalkNsText() {
 872                 global $wgContLang;
 873                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
 874         }
 875
 876         /**
 877          * Could this title have a corresponding talk page?
 878          *
 879          * @return Bool TRUE or FALSE
 880          */
 881         public function canTalk() {
 882                 return MWNamespace::canTalk( $this->mNamespace );
 883         }
 884
 885         /**
 886          * Is this in a namespace that allows actual pages?
 887          *
 888          * @return Bool
 889          * @internal note -- uses hardcoded namespace index instead of constants
 890          */
 891         public function canExist() {
 892                 return $this->mNamespace >= NS_MAIN;
 893         }
 894
 895         /**
 896          * Can this title be added to a user's watchlist?
 897          *
 898          * @return Bool TRUE or FALSE
 899          */
 900         public function isWatchable() {
 901                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
 902         }
 903
 904         /**
 905          * Returns true if this is a special page.
 906          *
 907          * @return boolean
 908          */
 909         public function isSpecialPage() {
 910                 return $this->getNamespace() == NS_SPECIAL;
 911         }
 912
 913         /**
 914          * Returns true if this title resolves to the named special page
 915          *
 916          * @param string $name The special page name
 917          * @return boolean
 918          */
 919         public function isSpecial( $name ) {
 920                 if ( $this->isSpecialPage() ) {
 921                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
 922                         if ( $name == $thisName ) {
 923                                 return true;
 924                         }
 925                 }
 926                 return false;
 927         }
 928
 929         /**
 930          * If the Title refers to a special page alias which is not the local default, resolve
 931          * the alias, and localise the name as necessary.  Otherwise, return $this
 932          *
 933          * @return Title
 934          */
 935         public function fixSpecialName() {
 936                 if ( $this->isSpecialPage() ) {
 937                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
 938                         if ( $canonicalName ) {
 939                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
 940                                 if ( $localName != $this->mDbkeyform ) {
 941                                         return Title::makeTitle( NS_SPECIAL, $localName );
 942                                 }
 943                         }
 944                 }
 945                 return $this;
 946         }
 947
 948         /**
 949          * Returns true if the title is inside the specified namespace.
 950          *
 951          * Please make use of this instead of comparing to getNamespace()
 952          * This function is much more resistant to changes we may make
 953          * to namespaces than code that makes direct comparisons.
 954          * @param int $ns The namespace
 955          * @return bool
 956          * @since 1.19
 957          */
 958         public function inNamespace( $ns ) {
 959                 return MWNamespace::equals( $this->getNamespace(), $ns );
 960         }
 961
 962         /**
 963          * Returns true if the title is inside one of the specified namespaces.
 964          *
 965          * @param ...$namespaces The namespaces to check for
 966          * @return bool
 967          * @since 1.19
 968          */
 969         public function inNamespaces( /* ... */ ) {
 970                 $namespaces = func_get_args();
 971                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
 972                         $namespaces = $namespaces[0];
 973                 }
 974
 975                 foreach ( $namespaces as $ns ) {
 976                         if ( $this->inNamespace( $ns ) ) {
 977                                 return true;
 978                         }
 979                 }
 980
 981                 return false;
 982         }
 983
 984         /**
 985          * Returns true if the title has the same subject namespace as the
 986          * namespace specified.
 987          * For example this method will take NS_USER and return true if namespace
 988          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
 989          * as their subject namespace.
 990          *
 991          * This is MUCH simpler than individually testing for equivalence
 992          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
 993          * @since 1.19
 994          * @param $ns int
 995          * @return bool
 996          */
 997         public function hasSubjectNamespace( $ns ) {
 998                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
 999         }
1000
1001         /**
1002          * Is this Title in a namespace which contains content?
1003          * In other words, is this a content page, for the purposes of calculating
1004          * statistics, etc?
1005          *
1006          * @return Boolean
1007          */
1008         public function isContentPage() {
1009                 return MWNamespace::isContent( $this->getNamespace() );
1010         }
1011
1012         /**
1013          * Would anybody with sufficient privileges be able to move this page?
1014          * Some pages just aren't movable.
1015          *
1016          * @return Bool TRUE or FALSE
1017          */
1018         public function isMovable() {
1019                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1020                         // Interwiki title or immovable namespace. Hooks don't get to override here
1021                         return false;
1022                 }
1023
1024                 $result = true;
1025                 wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
1026                 return $result;
1027         }
1028
1029         /**
1030          * Is this the mainpage?
1031          * @note Title::newFromText seems to be sufficiently optimized by the title
1032          * cache that we don't need to over-optimize by doing direct comparisons and
1033          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1034          * ends up reporting something differently than $title->isMainPage();
1035          *
1036          * @since 1.18
1037          * @return Bool
1038          */
1039         public function isMainPage() {
1040                 return $this->equals( Title::newMainPage() );
1041         }
1042
1043         /**
1044          * Is this a subpage?
1045          *
1046          * @return Bool
1047          */
1048         public function isSubpage() {
1049                 return MWNamespace::hasSubpages( $this->mNamespace )
1050                         ? strpos( $this->getText(), '/' ) !== false
1051                         : false;
1052         }
1053
1054         /**
1055          * Is this a conversion table for the LanguageConverter?
1056          *
1057          * @return Bool
1058          */
1059         public function isConversionTable() {
1060                 // @todo ConversionTable should become a separate content model.
1061
1062                 return $this->getNamespace() == NS_MEDIAWIKI &&
1063                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1064         }
1065
1066         /**
1067          * Does that page contain wikitext, or it is JS, CSS or whatever?
1068          *
1069          * @return Bool
1070          */
1071         public function isWikitextPage() {
1072                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1073         }
1074
1075         /**
1076          * Could this page contain custom CSS or JavaScript for the global UI.
1077          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1078          * or CONTENT_MODEL_JAVASCRIPT.
1079          *
1080          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage() for that!
1081          *
1082          * Note that this method should not return true for pages that contain and show "inactive" CSS or JS.
1083          *
1084          * @return Bool
1085          */
1086         public function isCssOrJsPage() {
1087                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1088                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1089                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1090
1091                 #NOTE: this hook is also called in ContentHandler::getDefaultModel. It's called here again to make sure
1092                 #      hook functions can force this method to return true even outside the mediawiki namespace.
1093
1094                 wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ) );
1095
1096                 return $isCssOrJsPage;
1097         }
1098
1099         /**
1100          * Is this a .css or .js subpage of a user page?
1101          * @return Bool
1102          */
1103         public function isCssJsSubpage() {
1104                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1105                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1106                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1107         }
1108
1109         /**
1110          * Trim down a .css or .js subpage title to get the corresponding skin name
1111          *
1112          * @return string containing skin name from .css or .js subpage title
1113          */
1114         public function getSkinFromCssJsSubpage() {
1115                 $subpage = explode( '/', $this->mTextform );
1116                 $subpage = $subpage[count( $subpage ) - 1];
1117                 $lastdot = strrpos( $subpage, '.' );
1118                 if ( $lastdot === false ) {
1119                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1120                 }
1121                 return substr( $subpage, 0, $lastdot );
1122         }
1123
1124         /**
1125          * Is this a .css subpage of a user page?
1126          *
1127          * @return Bool
1128          */
1129         public function isCssSubpage() {
1130                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1131                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1132         }
1133
1134         /**
1135          * Is this a .js subpage of a user page?
1136          *
1137          * @return Bool
1138          */
1139         public function isJsSubpage() {
1140                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1141                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1142         }
1143
1144         /**
1145          * Is this a talk page of some sort?
1146          *
1147          * @return Bool
1148          */
1149         public function isTalkPage() {
1150                 return MWNamespace::isTalk( $this->getNamespace() );
1151         }
1152
1153         /**
1154          * Get a Title object associated with the talk page of this article
1155          *
1156          * @return Title the object for the talk page
1157          */
1158         public function getTalkPage() {
1159                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1160         }
1161
1162         /**
1163          * Get a title object associated with the subject page of this
1164          * talk page
1165          *
1166          * @return Title the object for the subject page
1167          */
1168         public function getSubjectPage() {
1169                 // Is this the same title?
1170                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1171                 if ( $this->getNamespace() == $subjectNS ) {
1172                         return $this;
1173                 }
1174                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1175         }
1176
1177         /**
1178          * Get the default namespace index, for when there is no namespace
1179          *
1180          * @return Int Default namespace index
1181          */
1182         public function getDefaultNamespace() {
1183                 return $this->mDefaultNamespace;
1184         }
1185
1186         /**
1187          * Get title for search index
1188          *
1189          * @return String a stripped-down title string ready for the
1190          *  search index
1191          */
1192         public function getIndexTitle() {
1193                 return Title::indexTitle( $this->mNamespace, $this->mTextform );
1194         }
1195
1196         /**
1197          * Get the Title fragment (i.e.\ the bit after the #) in text form
1198          *
1199          * Use Title::hasFragment to check for a fragment
1200          *
1201          * @return String Title fragment
1202          */
1203         public function getFragment() {
1204                 return $this->mFragment;
1205         }
1206
1207         /**
1208          * Check if a Title fragment is set
1209          *
1210          * @return bool
1211          * @since 1.23
1212          */
1213         public function hasFragment() {
1214                 return $this->mFragment !== '';
1215         }
1216
1217         /**
1218          * Get the fragment in URL form, including the "#" character if there is one
1219          * @return String Fragment in URL form
1220          */
1221         public function getFragmentForURL() {
1222                 if ( !$this->hasFragment() ) {
1223                         return '';
1224                 } else {
1225                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1226                 }
1227         }
1228
1229         /**
1230          * Set the fragment for this title. Removes the first character from the
1231          * specified fragment before setting, so it assumes you're passing it with
1232          * an initial "#".
1233          *
1234          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1235          * Still in active use privately.
1236          *
1237          * @param string $fragment text
1238          */
1239         public function setFragment( $fragment ) {
1240                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1241         }
1242
1243         /**
1244          * Prefix some arbitrary text with the namespace or interwiki prefix
1245          * of this object
1246          *
1247          * @param string $name the text
1248          * @return String the prefixed text
1249          * @private
1250          */
1251         private function prefix( $name ) {
1252                 $p = '';
1253                 if ( $this->isExternal() ) {
1254                         $p = $this->mInterwiki . ':';
1255                 }
1256
1257                 if ( 0 != $this->mNamespace ) {
1258                         $p .= $this->getNsText() . ':';
1259                 }
1260                 return $p . $name;
1261         }
1262
1263         /**
1264          * Get the prefixed database key form
1265          *
1266          * @return String the prefixed title, with underscores and
1267          *  any interwiki and namespace prefixes
1268          */
1269         public function getPrefixedDBkey() {
1270                 $s = $this->prefix( $this->mDbkeyform );
1271                 $s = str_replace( ' ', '_', $s );
1272                 return $s;
1273         }
1274
1275         /**
1276          * Get the prefixed title with spaces.
1277          * This is the form usually used for display
1278          *
1279          * @return String the prefixed title, with spaces
1280          */
1281         public function getPrefixedText() {
1282                 if ( $this->mPrefixedText === null ) {
1283                         $s = $this->prefix( $this->mTextform );
1284                         $s = str_replace( '_', ' ', $s );
1285                         $this->mPrefixedText = $s;
1286                 }
1287                 return $this->mPrefixedText;
1288         }
1289
1290         /**
1291          * Return a string representation of this title
1292          *
1293          * @return String representation of this title
1294          */
1295         public function __toString() {
1296                 return $this->getPrefixedText();
1297         }
1298
1299         /**
1300          * Get the prefixed title with spaces, plus any fragment
1301          * (part beginning with '#')
1302          *
1303          * @return String the prefixed title, with spaces and the fragment, including '#'
1304          */
1305         public function getFullText() {
1306                 $text = $this->getPrefixedText();
1307                 if ( $this->hasFragment() ) {
1308                         $text .= '#' . $this->getFragment();
1309                 }
1310                 return $text;
1311         }
1312
1313         /**
1314          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1315          *
1316          * @par Example:
1317          * @code
1318          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1319          * # returns: 'Foo'
1320          * @endcode
1321          *
1322          * @return String Root name
1323          * @since 1.20
1324          */
1325         public function getRootText() {
1326                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1327                         return $this->getText();
1328                 }
1329
1330                 return strtok( $this->getText(), '/' );
1331         }
1332
1333         /**
1334          * Get the root page name title, i.e. the leftmost part before any slashes
1335          *
1336          * @par Example:
1337          * @code
1338          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1339          * # returns: Title{User:Foo}
1340          * @endcode
1341          *
1342          * @return Title Root title
1343          * @since 1.20
1344          */
1345         public function getRootTitle() {
1346                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1347         }
1348
1349         /**
1350          * Get the base page name without a namespace, i.e. the part before the subpage name
1351          *
1352          * @par Example:
1353          * @code
1354          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1355          * # returns: 'Foo/Bar'
1356          * @endcode
1357          *
1358          * @return String Base name
1359          */
1360         public function getBaseText() {
1361                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1362                         return $this->getText();
1363                 }
1364
1365                 $parts = explode( '/', $this->getText() );
1366                 # Don't discard the real title if there's no subpage involved
1367                 if ( count( $parts ) > 1 ) {
1368                         unset( $parts[count( $parts ) - 1] );
1369                 }
1370                 return implode( '/', $parts );
1371         }
1372
1373         /**
1374          * Get the base page name title, i.e. the part before the subpage name
1375          *
1376          * @par Example:
1377          * @code
1378          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1379          * # returns: Title{User:Foo/Bar}
1380          * @endcode
1381          *
1382          * @return Title Base title
1383          * @since 1.20
1384          */
1385         public function getBaseTitle() {
1386                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1387         }
1388
1389         /**
1390          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1391          *
1392          * @par Example:
1393          * @code
1394          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1395          * # returns: "Baz"
1396          * @endcode
1397          *
1398          * @return String Subpage name
1399          */
1400         public function getSubpageText() {
1401                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1402                         return $this->mTextform;
1403                 }
1404                 $parts = explode( '/', $this->mTextform );
1405                 return $parts[count( $parts ) - 1];
1406         }
1407
1408         /**
1409          * Get the title for a subpage of the current page
1410          *
1411          * @par Example:
1412          * @code
1413          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1414          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1415          * @endcode
1416          *
1417          * @param string $text The subpage name to add to the title
1418          * @return Title Subpage title
1419          * @since 1.20
1420          */
1421         public function getSubpage( $text ) {
1422                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1423         }
1424
1425         /**
1426          * Get the HTML-escaped displayable text form.
1427          * Used for the title field in <a> tags.
1428          *
1429          * @return String the text, including any prefixes
1430          * @deprecated since 1.19
1431          */
1432         public function getEscapedText() {
1433                 wfDeprecated( __METHOD__, '1.19' );
1434                 return htmlspecialchars( $this->getPrefixedText() );
1435         }
1436
1437         /**
1438          * Get a URL-encoded form of the subpage text
1439          *
1440          * @return String URL-encoded subpage name
1441          */
1442         public function getSubpageUrlForm() {
1443                 $text = $this->getSubpageText();
1444                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1445                 return $text;
1446         }
1447
1448         /**
1449          * Get a URL-encoded title (not an actual URL) including interwiki
1450          *
1451          * @return String the URL-encoded form
1452          */
1453         public function getPrefixedURL() {
1454                 $s = $this->prefix( $this->mDbkeyform );
1455                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1456                 return $s;
1457         }
1458
1459         /**
1460          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1461          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1462          * second argument named variant. This was deprecated in favor
1463          * of passing an array of option with a "variant" key
1464          * Once $query2 is removed for good, this helper can be dropped
1465          * and the wfArrayToCgi moved to getLocalURL();
1466          *
1467          * @since 1.19 (r105919)
1468          * @param $query
1469          * @param $query2 bool
1470          * @return String
1471          */
1472         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1473                 if ( $query2 !== false ) {
1474                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1475                                 "method called with a second parameter is deprecated. Add your " .
1476                                 "parameter to an array passed as the first parameter.", "1.19" );
1477                 }
1478                 if ( is_array( $query ) ) {
1479                         $query = wfArrayToCgi( $query );
1480                 }
1481                 if ( $query2 ) {
1482                         if ( is_string( $query2 ) ) {
1483                                 // $query2 is a string, we will consider this to be
1484                                 // a deprecated $variant argument and add it to the query
1485                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1486                         } else {
1487                                 $query2 = wfArrayToCgi( $query2 );
1488                         }
1489                         // If we have $query content add a & to it first
1490                         if ( $query ) {
1491                                 $query .= '&';
1492                         }
1493                         // Now append the queries together
1494                         $query .= $query2;
1495                 }
1496                 return $query;
1497         }
1498
1499         /**
1500          * Get a real URL referring to this title, with interwiki link and
1501          * fragment
1502          *
1503          * See getLocalURL for the arguments.
1504          *
1505          * @see self::getLocalURL
1506          * @see wfExpandUrl
1507          * @param $query
1508          * @param $query2 bool
1509          * @param $proto Protocol type to use in URL
1510          * @return String the URL
1511          */
1512         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1513                 $query = self::fixUrlQueryArgs( $query, $query2 );
1514
1515                 # Hand off all the decisions on urls to getLocalURL
1516                 $url = $this->getLocalURL( $query );
1517
1518                 # Expand the url to make it a full url. Note that getLocalURL has the
1519                 # potential to output full urls for a variety of reasons, so we use
1520                 # wfExpandUrl instead of simply prepending $wgServer
1521                 $url = wfExpandUrl( $url, $proto );
1522
1523                 # Finally, add the fragment.
1524                 $url .= $this->getFragmentForURL();
1525
1526                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1527                 return $url;
1528         }
1529
1530         /**
1531          * Get a URL with no fragment or server name.  If this page is generated
1532          * with action=render, $wgServer is prepended.
1533          *
1534          * @param string|array $query an optional query string,
1535          *   not used for interwiki links. Can be specified as an associative array as well,
1536          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1537          *   Some query patterns will trigger various shorturl path replacements.
1538          * @param $query2 Mixed: An optional secondary query array. This one MUST
1539          *   be an array. If a string is passed it will be interpreted as a deprecated
1540          *   variant argument and urlencoded into a variant= argument.
1541          *   This second query argument will be added to the $query
1542          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1543          *   pair in the first parameter array instead.
1544          *
1545          * @return String the URL
1546          */
1547         public function getLocalURL( $query = '', $query2 = false ) {
1548                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1549
1550                 $query = self::fixUrlQueryArgs( $query, $query2 );
1551
1552                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1553                 if ( $interwiki ) {
1554                         $namespace = $this->getNsText();
1555                         if ( $namespace != '' ) {
1556                                 # Can this actually happen? Interwikis shouldn't be parsed.
1557                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1558                                 $namespace .= ':';
1559                         }
1560                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1561                         $url = wfAppendQuery( $url, $query );
1562                 } else {
1563                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1564                         if ( $query == '' ) {
1565                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1566                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1567                         } else {
1568                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1569                                 $url = false;
1570                                 $matches = array();
1571
1572                                 if ( !empty( $wgActionPaths )
1573                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1574                                 ) {
1575                                         $action = urldecode( $matches[2] );
1576                                         if ( isset( $wgActionPaths[$action] ) ) {
1577                                                 $query = $matches[1];
1578                                                 if ( isset( $matches[4] ) ) {
1579                                                         $query .= $matches[4];
1580                                                 }
1581                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1582                                                 if ( $query != '' ) {
1583                                                         $url = wfAppendQuery( $url, $query );
1584                                                 }
1585                                         }
1586                                 }
1587
1588                                 if ( $url === false
1589                                         && $wgVariantArticlePath
1590                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1591                                         && $this->getPageLanguage()->hasVariants()
1592                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1593                                 ) {
1594                                         $variant = urldecode( $matches[1] );
1595                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1596                                                 // Only do the variant replacement if the given variant is a valid
1597                                                 // variant for the page's language.
1598                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1599                                                 $url = str_replace( '$1', $dbkey, $url );
1600                                         }
1601                                 }
1602
1603                                 if ( $url === false ) {
1604                                         if ( $query == '-' ) {
1605                                                 $query = '';
1606                                         }
1607                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1608                                 }
1609                         }
1610
1611                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1612
1613                         // @todo FIXME: This causes breakage in various places when we
1614                         // actually expected a local URL and end up with dupe prefixes.
1615                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1616                                 $url = $wgServer . $url;
1617                         }
1618                 }
1619                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1620                 return $url;
1621         }
1622
1623         /**
1624          * Get a URL that's the simplest URL that will be valid to link, locally,
1625          * to the current Title.  It includes the fragment, but does not include
1626          * the server unless action=render is used (or the link is external).  If
1627          * there's a fragment but the prefixed text is empty, we just return a link
1628          * to the fragment.
1629          *
1630          * The result obviously should not be URL-escaped, but does need to be
1631          * HTML-escaped if it's being output in HTML.
1632          *
1633          * See getLocalURL for the arguments.
1634          *
1635          * @param $query
1636          * @param $query2 bool
1637          * @param $proto Protocol to use; setting this will cause a full URL to be used
1638          * @see self::getLocalURL
1639          * @return String the URL
1640          */
1641         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1642                 wfProfileIn( __METHOD__ );
1643                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1644                         $ret = $this->getFullURL( $query, $query2, $proto );
1645                 } elseif ( $this->getPrefixedText() === '' && $this->getFragment() !== '' ) {
1646                         $ret = $this->getFragmentForURL();
1647                 } else {
1648                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1649                 }
1650                 wfProfileOut( __METHOD__ );
1651                 return $ret;
1652         }
1653
1654         /**
1655          * Get an HTML-escaped version of the URL form, suitable for
1656          * using in a link, without a server name or fragment
1657          *
1658          * See getLocalURL for the arguments.
1659          *
1660          * @see self::getLocalURL
1661          * @param $query string
1662          * @param $query2 bool|string
1663          * @return String the URL
1664          * @deprecated since 1.19
1665          */
1666         public function escapeLocalURL( $query = '', $query2 = false ) {
1667                 wfDeprecated( __METHOD__, '1.19' );
1668                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1669         }
1670
1671         /**
1672          * Get an HTML-escaped version of the URL form, suitable for
1673          * using in a link, including the server name and fragment
1674          *
1675          * See getLocalURL for the arguments.
1676          *
1677          * @see self::getLocalURL
1678          * @return String the URL
1679          * @deprecated since 1.19
1680          */
1681         public function escapeFullURL( $query = '', $query2 = false ) {
1682                 wfDeprecated( __METHOD__, '1.19' );
1683                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1684         }
1685
1686         /**
1687          * Get the URL form for an internal link.
1688          * - Used in various Squid-related code, in case we have a different
1689          * internal hostname for the server from the exposed one.
1690          *
1691          * This uses $wgInternalServer to qualify the path, or $wgServer
1692          * if $wgInternalServer is not set. If the server variable used is
1693          * protocol-relative, the URL will be expanded to http://
1694          *
1695          * See getLocalURL for the arguments.
1696          *
1697          * @see self::getLocalURL
1698          * @return String the URL
1699          */
1700         public function getInternalURL( $query = '', $query2 = false ) {
1701                 global $wgInternalServer, $wgServer;
1702                 $query = self::fixUrlQueryArgs( $query, $query2 );
1703                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1704                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1705                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1706                 return $url;
1707         }
1708
1709         /**
1710          * Get the URL for a canonical link, for use in things like IRC and
1711          * e-mail notifications. Uses $wgCanonicalServer and the
1712          * GetCanonicalURL hook.
1713          *
1714          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1715          *
1716          * See getLocalURL for the arguments.
1717          *
1718          * @see self::getLocalURL
1719          * @return string The URL
1720          * @since 1.18
1721          */
1722         public function getCanonicalURL( $query = '', $query2 = false ) {
1723                 $query = self::fixUrlQueryArgs( $query, $query2 );
1724                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1725                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1726                 return $url;
1727         }
1728
1729         /**
1730          * HTML-escaped version of getCanonicalURL()
1731          *
1732          * See getLocalURL for the arguments.
1733          *
1734          * @see self::getLocalURL
1735          * @since 1.18
1736          * @return string
1737          * @deprecated since 1.19
1738          */
1739         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1740                 wfDeprecated( __METHOD__, '1.19' );
1741                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1742         }
1743
1744         /**
1745          * Get the edit URL for this Title
1746          *
1747          * @return String the URL, or a null string if this is an
1748          *  interwiki link
1749          */
1750         public function getEditURL() {
1751                 if ( $this->isExternal() ) {
1752                         return '';
1753                 }
1754                 $s = $this->getLocalURL( 'action=edit' );
1755
1756                 return $s;
1757         }
1758
1759         /**
1760          * Is $wgUser watching this page?
1761          *
1762          * @deprecated in 1.20; use User::isWatched() instead.
1763          * @return Bool
1764          */
1765         public function userIsWatching() {
1766                 global $wgUser;
1767
1768                 if ( is_null( $this->mWatched ) ) {
1769                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1770                                 $this->mWatched = false;
1771                         } else {
1772                                 $this->mWatched = $wgUser->isWatched( $this );
1773                         }
1774                 }
1775                 return $this->mWatched;
1776         }
1777
1778         /**
1779          * Can $wgUser read this page?
1780          *
1781          * @deprecated in 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1782          * @return Bool
1783          * @todo fold these checks into userCan()
1784          */
1785         public function userCanRead() {
1786                 wfDeprecated( __METHOD__, '1.19' );
1787                 return $this->userCan( 'read' );
1788         }
1789
1790         /**
1791          * Can $user perform $action on this page?
1792          * This skips potentially expensive cascading permission checks
1793          * as well as avoids expensive error formatting
1794          *
1795          * Suitable for use for nonessential UI controls in common cases, but
1796          * _not_ for functional access control.
1797          *
1798          * May provide false positives, but should never provide a false negative.
1799          *
1800          * @param string $action action that permission needs to be checked for
1801          * @param $user User to check (since 1.19); $wgUser will be used if not
1802          *              provided.
1803          * @return Bool
1804          */
1805         public function quickUserCan( $action, $user = null ) {
1806                 return $this->userCan( $action, $user, false );
1807         }
1808
1809         /**
1810          * Can $user perform $action on this page?
1811          *
1812          * @param string $action action that permission needs to be checked for
1813          * @param $user User to check (since 1.19); $wgUser will be used if not
1814          *   provided.
1815          * @param bool $doExpensiveQueries Set this to false to avoid doing
1816          *   unnecessary queries.
1817          * @return Bool
1818          */
1819         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1820                 if ( !$user instanceof User ) {
1821                         global $wgUser;
1822                         $user = $wgUser;
1823                 }
1824                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries, true ) );
1825         }
1826
1827         /**
1828          * Can $user perform $action on this page?
1829          *
1830          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1831          *
1832          * @param string $action action that permission needs to be checked for
1833          * @param $user User to check
1834          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1835          *   queries by skipping checks for cascading protections and user blocks.
1836          * @param array $ignoreErrors of Strings Set this to a list of message keys
1837          *   whose corresponding errors may be ignored.
1838          * @return Array of arguments to wfMessage to explain permissions problems.
1839          */
1840         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
1841                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1842
1843                 // Remove the errors being ignored.
1844                 foreach ( $errors as $index => $error ) {
1845                         $error_key = is_array( $error ) ? $error[0] : $error;
1846
1847                         if ( in_array( $error_key, $ignoreErrors ) ) {
1848                                 unset( $errors[$index] );
1849                         }
1850                 }
1851
1852                 return $errors;
1853         }
1854
1855         /**
1856          * Permissions checks that fail most often, and which are easiest to test.
1857          *
1858          * @param string $action the action to check
1859          * @param $user User user to check
1860          * @param array $errors list of current errors
1861          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1862          * @param $short Boolean short circuit on first error
1863          *
1864          * @return Array list of errors
1865          */
1866         private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1867                 if ( !wfRunHooks( 'TitleQuickPermissions', array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) ) ) {
1868                         return $errors;
1869                 }
1870
1871                 if ( $action == 'create' ) {
1872                         if (
1873                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1874                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1875                         ) {
1876                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1877                         }
1878                 } elseif ( $action == 'move' ) {
1879                         if ( !$user->isAllowed( 'move-rootuserpages' )
1880                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1881                                 // Show user page-specific message only if the user can move other pages
1882                                 $errors[] = array( 'cant-move-user-page' );
1883                         }
1884
1885                         // Check if user is allowed to move files if it's a file
1886                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1887                                 $errors[] = array( 'movenotallowedfile' );
1888                         }
1889
1890                         if ( !$user->isAllowed( 'move' ) ) {
1891                                 // User can't move anything
1892                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1893                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1894                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1895                                         // custom message if logged-in users without any special rights can move
1896                                         $errors[] = array( 'movenologintext' );
1897                                 } else {
1898                                         $errors[] = array( 'movenotallowed' );
1899                                 }
1900                         }
1901                 } elseif ( $action == 'move-target' ) {
1902                         if ( !$user->isAllowed( 'move' ) ) {
1903                                 // User can't move anything
1904                                 $errors[] = array( 'movenotallowed' );
1905                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1906                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1907                                 // Show user page-specific message only if the user can move other pages
1908                                 $errors[] = array( 'cant-move-to-user-page' );
1909                         }
1910                 } elseif ( !$user->isAllowed( $action ) ) {
1911                         $errors[] = $this->missingPermissionError( $action, $short );
1912                 }
1913
1914                 return $errors;
1915         }
1916
1917         /**
1918          * Add the resulting error code to the errors array
1919          *
1920          * @param array $errors list of current errors
1921          * @param $result Mixed result of errors
1922          *
1923          * @return Array list of errors
1924          */
1925         private function resultToError( $errors, $result ) {
1926                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1927                         // A single array representing an error
1928                         $errors[] = $result;
1929                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
1930                         // A nested array representing multiple errors
1931                         $errors = array_merge( $errors, $result );
1932                 } elseif ( $result !== '' && is_string( $result ) ) {
1933                         // A string representing a message-id
1934                         $errors[] = array( $result );
1935                 } elseif ( $result === false ) {
1936                         // a generic "We don't want them to do that"
1937                         $errors[] = array( 'badaccess-group0' );
1938                 }
1939                 return $errors;
1940         }
1941
1942         /**
1943          * Check various permission hooks
1944          *
1945          * @param string $action the action to check
1946          * @param $user User user to check
1947          * @param array $errors list of current errors
1948          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1949          * @param $short Boolean short circuit on first error
1950          *
1951          * @return Array list of errors
1952          */
1953         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
1954                 // Use getUserPermissionsErrors instead
1955                 $result = '';
1956                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
1957                         return $result ? array() : array( array( 'badaccess-group0' ) );
1958                 }
1959                 // Check getUserPermissionsErrors hook
1960                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
1961                         $errors = $this->resultToError( $errors, $result );
1962                 }
1963                 // Check getUserPermissionsErrorsExpensive hook
1964                 if (
1965                         $doExpensiveQueries
1966                         && !( $short && count( $errors ) > 0 )
1967                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
1968                 ) {
1969                         $errors = $this->resultToError( $errors, $result );
1970                 }
1971
1972                 return $errors;
1973         }
1974
1975         /**
1976          * Check permissions on special pages & namespaces
1977          *
1978          * @param string $action the action to check
1979          * @param $user User user to check
1980          * @param array $errors list of current errors
1981          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1982          * @param $short Boolean short circuit on first error
1983          *
1984          * @return Array list of errors
1985          */
1986         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1987                 # Only 'createaccount' can be performed on special pages,
1988                 # which don't actually exist in the DB.
1989                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
1990                         $errors[] = array( 'ns-specialprotected' );
1991                 }
1992
1993                 # Check $wgNamespaceProtection for restricted namespaces
1994                 if ( $this->isNamespaceProtected( $user ) ) {
1995                         $ns = $this->mNamespace == NS_MAIN ?
1996                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
1997                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
1998                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
1999                 }
2000
2001                 return $errors;
2002         }
2003
2004         /**
2005          * Check CSS/JS sub-page permissions
2006          *
2007          * @param string $action the action to check
2008          * @param $user User user to check
2009          * @param array $errors list of current errors
2010          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2011          * @param $short Boolean short circuit on first error
2012          *
2013          * @return Array list of errors
2014          */
2015         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2016                 # Protect css/js subpages of user pages
2017                 # XXX: this might be better using restrictions
2018                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2019                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2020                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2021                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2022                                         $errors[] = array( 'mycustomcssprotected' );
2023                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2024                                         $errors[] = array( 'mycustomjsprotected' );
2025                                 }
2026                         } else {
2027                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2028                                         $errors[] = array( 'customcssprotected' );
2029                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2030                                         $errors[] = array( 'customjsprotected' );
2031                                 }
2032                         }
2033                 }
2034
2035                 return $errors;
2036         }
2037
2038         /**
2039          * Check against page_restrictions table requirements on this
2040          * page. The user must possess all required rights for this
2041          * action.
2042          *
2043          * @param string $action the action to check
2044          * @param $user User user to check
2045          * @param array $errors list of current errors
2046          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2047          * @param $short Boolean short circuit on first error
2048          *
2049          * @return Array list of errors
2050          */
2051         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2052                 foreach ( $this->getRestrictions( $action ) as $right ) {
2053                         // Backwards compatibility, rewrite sysop -> editprotected
2054                         if ( $right == 'sysop' ) {
2055                                 $right = 'editprotected';
2056                         }
2057                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2058                         if ( $right == 'autoconfirmed' ) {
2059                                 $right = 'editsemiprotected';
2060                         }
2061                         if ( $right == '' ) {
2062                                 continue;
2063                         }
2064                         if ( !$user->isAllowed( $right ) ) {
2065                                 $errors[] = array( 'protectedpagetext', $right );
2066                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2067                                 $errors[] = array( 'protectedpagetext', 'protect' );
2068                         }
2069                 }
2070
2071                 return $errors;
2072         }
2073
2074         /**
2075          * Check restrictions on cascading pages.
2076          *
2077          * @param string $action the action to check
2078          * @param $user User to check
2079          * @param array $errors list of current errors
2080          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2081          * @param $short Boolean short circuit on first error
2082          *
2083          * @return Array list of errors
2084          */
2085         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2086                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2087                         # We /could/ use the protection level on the source page, but it's
2088                         # fairly ugly as we have to establish a precedence hierarchy for pages
2089                         # included by multiple cascade-protected pages. So just restrict
2090                         # it to people with 'protect' permission, as they could remove the
2091                         # protection anyway.
2092                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2093                         # Cascading protection depends on more than this page...
2094                         # Several cascading protected pages may include this page...
2095                         # Check each cascading level
2096                         # This is only for protection restrictions, not for all actions
2097                         if ( isset( $restrictions[$action] ) ) {
2098                                 foreach ( $restrictions[$action] as $right ) {
2099                                         // Backwards compatibility, rewrite sysop -> editprotected
2100                                         if ( $right == 'sysop' ) {
2101                                                 $right = 'editprotected';
2102                                         }
2103                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2104                                         if ( $right == 'autoconfirmed' ) {
2105                                                 $right = 'editsemiprotected';
2106                                         }
2107                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2108                                                 $pages = '';
2109                                                 foreach ( $cascadingSources as $page ) {
2110                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2111                                                 }
2112                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2113                                         }
2114                                 }
2115                         }
2116                 }
2117
2118                 return $errors;
2119         }
2120
2121         /**
2122          * Check action permissions not already checked in checkQuickPermissions
2123          *
2124          * @param string $action the action to check
2125          * @param $user User to check
2126          * @param array $errors list of current errors
2127          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2128          * @param $short Boolean short circuit on first error
2129          *
2130          * @return Array list of errors
2131          */
2132         private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2133                 global $wgDeleteRevisionsLimit, $wgLang;
2134
2135                 if ( $action == 'protect' ) {
2136                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $doExpensiveQueries, true ) ) ) {
2137                                 // If they can't edit, they shouldn't protect.
2138                                 $errors[] = array( 'protect-cantedit' );
2139                         }
2140                 } elseif ( $action == 'create' ) {
2141                         $title_protection = $this->getTitleProtection();
2142                         if ( $title_protection ) {
2143                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2144                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2145                                 }
2146                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2147                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2148                                 }
2149                                 if ( $title_protection['pt_create_perm'] == ''
2150                                         || !$user->isAllowed( $title_protection['pt_create_perm'] )
2151                                 ) {
2152                                         $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
2153                                 }
2154                         }
2155                 } elseif ( $action == 'move' ) {
2156                         // Check for immobile pages
2157                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2158                                 // Specific message for this case
2159                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2160                         } elseif ( !$this->isMovable() ) {
2161                                 // Less specific message for rarer cases
2162                                 $errors[] = array( 'immobile-source-page' );
2163                         }
2164                 } elseif ( $action == 'move-target' ) {
2165                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2166                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2167                         } elseif ( !$this->isMovable() ) {
2168                                 $errors[] = array( 'immobile-target-page' );
2169                         }
2170                 } elseif ( $action == 'delete' ) {
2171                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2172                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2173                         ) {
2174                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2175                         }
2176                 }
2177                 return $errors;
2178         }
2179
2180         /**
2181          * Check that the user isn't blocked from editing.
2182          *
2183          * @param string $action the action to check
2184          * @param $user User to check
2185          * @param array $errors list of current errors
2186          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2187          * @param $short Boolean short circuit on first error
2188          *
2189          * @return Array list of errors
2190          */
2191         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2192                 // Account creation blocks handled at userlogin.
2193                 // Unblocking handled in SpecialUnblock
2194                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2195                         return $errors;
2196                 }
2197
2198                 global $wgEmailConfirmToEdit;
2199
2200                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2201                         $errors[] = array( 'confirmedittext' );
2202                 }
2203
2204                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2205                         // Don't block the user from editing their own talk page unless they've been
2206                         // explicitly blocked from that too.
2207                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2208                         // @todo FIXME: Pass the relevant context into this function.
2209                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2210                 }
2211
2212                 return $errors;
2213         }
2214
2215         /**
2216          * Check that the user is allowed to read this page.
2217          *
2218          * @param string $action the action to check
2219          * @param $user User to check
2220          * @param array $errors list of current errors
2221          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2222          * @param $short Boolean short circuit on first error
2223          *
2224          * @return Array list of errors
2225          */
2226         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2227                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2228
2229                 $whitelisted = false;
2230                 if ( User::isEveryoneAllowed( 'read' ) ) {
2231                         # Shortcut for public wikis, allows skipping quite a bit of code
2232                         $whitelisted = true;
2233                 } elseif ( $user->isAllowed( 'read' ) ) {
2234                         # If the user is allowed to read pages, he is allowed to read all pages
2235                         $whitelisted = true;
2236                 } elseif ( $this->isSpecial( 'Userlogin' )
2237                         || $this->isSpecial( 'ChangePassword' )
2238                         || $this->isSpecial( 'PasswordReset' )
2239                 ) {
2240                         # Always grant access to the login page.
2241                         # Even anons need to be able to log in.
2242                         $whitelisted = true;
2243                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2244                         # Time to check the whitelist
2245                         # Only do these checks is there's something to check against
2246                         $name = $this->getPrefixedText();
2247                         $dbName = $this->getPrefixedDBkey();
2248
2249                         // Check for explicit whitelisting with and without underscores
2250                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2251                                 $whitelisted = true;
2252                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2253                                 # Old settings might have the title prefixed with
2254                                 # a colon for main-namespace pages
2255                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2256                                         $whitelisted = true;
2257                                 }
2258                         } elseif ( $this->isSpecialPage() ) {
2259                                 # If it's a special page, ditch the subpage bit and check again
2260                                 $name = $this->getDBkey();
2261                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2262                                 if ( $name ) {
2263                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2264                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2265                                                 $whitelisted = true;
2266                                         }
2267                                 }
2268                         }
2269                 }
2270
2271                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2272                         $name = $this->getPrefixedText();
2273                         // Check for regex whitelisting
2274                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2275                                 if ( preg_match( $listItem, $name ) ) {
2276                                         $whitelisted = true;
2277                                         break;
2278                                 }
2279                         }
2280                 }
2281
2282                 if ( !$whitelisted ) {
2283                         # If the title is not whitelisted, give extensions a chance to do so...
2284                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2285                         if ( !$whitelisted ) {
2286                                 $errors[] = $this->missingPermissionError( $action, $short );
2287                         }
2288                 }
2289
2290                 return $errors;
2291         }
2292
2293         /**
2294          * Get a description array when the user doesn't have the right to perform
2295          * $action (i.e. when User::isAllowed() returns false)
2296          *
2297          * @param string $action the action to check
2298          * @param $short Boolean short circuit on first error
2299          * @return Array list of errors
2300          */
2301         private function missingPermissionError( $action, $short ) {
2302                 // We avoid expensive display logic for quickUserCan's and such
2303                 if ( $short ) {
2304                         return array( 'badaccess-group0' );
2305                 }
2306
2307                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2308                         User::getGroupsWithPermission( $action ) );
2309
2310                 if ( count( $groups ) ) {
2311                         global $wgLang;
2312                         return array(
2313                                 'badaccess-groups',
2314                                 $wgLang->commaList( $groups ),
2315                                 count( $groups )
2316                         );
2317                 } else {
2318                         return array( 'badaccess-group0' );
2319                 }
2320         }
2321
2322         /**
2323          * Can $user perform $action on this page? This is an internal function,
2324          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2325          * checks on wfReadOnly() and blocks)
2326          *
2327          * @param string $action action that permission needs to be checked for
2328          * @param $user User to check
2329          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2330          * @param bool $short Set this to true to stop after the first permission error.
2331          * @return Array of arrays of the arguments to wfMessage to explain permissions problems.
2332          */
2333         protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
2334                 wfProfileIn( __METHOD__ );
2335
2336                 # Read has special handling
2337                 if ( $action == 'read' ) {
2338                         $checks = array(
2339                                 'checkPermissionHooks',
2340                                 'checkReadPermissions',
2341                         );
2342                 } else {
2343                         $checks = array(
2344                                 'checkQuickPermissions',
2345                                 'checkPermissionHooks',
2346                                 'checkSpecialsAndNSPermissions',
2347                                 'checkCSSandJSPermissions',
2348                                 'checkPageRestrictions',
2349                                 'checkCascadingSourcesRestrictions',
2350                                 'checkActionPermissions',
2351                                 'checkUserBlock'
2352                         );
2353                 }
2354
2355                 $errors = array();
2356                 while ( count( $checks ) > 0 &&
2357                                 !( $short && count( $errors ) > 0 ) ) {
2358                         $method = array_shift( $checks );
2359                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2360                 }
2361
2362                 wfProfileOut( __METHOD__ );
2363                 return $errors;
2364         }
2365
2366         /**
2367          * Get a filtered list of all restriction types supported by this wiki.
2368          * @param bool $exists True to get all restriction types that apply to
2369          * titles that do exist, False for all restriction types that apply to
2370          * titles that do not exist
2371          * @return array
2372          */
2373         public static function getFilteredRestrictionTypes( $exists = true ) {
2374                 global $wgRestrictionTypes;
2375                 $types = $wgRestrictionTypes;
2376                 if ( $exists ) {
2377                         # Remove the create restriction for existing titles
2378                         $types = array_diff( $types, array( 'create' ) );
2379                 } else {
2380                         # Only the create and upload restrictions apply to non-existing titles
2381                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2382                 }
2383                 return $types;
2384         }
2385
2386         /**
2387          * Returns restriction types for the current Title
2388          *
2389          * @return array applicable restriction types
2390          */
2391         public function getRestrictionTypes() {
2392                 if ( $this->isSpecialPage() ) {
2393                         return array();
2394                 }
2395
2396                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2397
2398                 if ( $this->getNamespace() != NS_FILE ) {
2399                         # Remove the upload restriction for non-file titles
2400                         $types = array_diff( $types, array( 'upload' ) );
2401                 }
2402
2403                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2404
2405                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2406                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2407
2408                 return $types;
2409         }
2410
2411         /**
2412          * Is this title subject to title protection?
2413          * Title protection is the one applied against creation of such title.
2414          *
2415          * @return Mixed An associative array representing any existent title
2416          *   protection, or false if there's none.
2417          */
2418         private function getTitleProtection() {
2419                 // Can't protect pages in special namespaces
2420                 if ( $this->getNamespace() < 0 ) {
2421                         return false;
2422                 }
2423
2424                 // Can't protect pages that exist.
2425                 if ( $this->exists() ) {
2426                         return false;
2427                 }
2428
2429                 if ( !isset( $this->mTitleProtection ) ) {
2430                         $dbr = wfGetDB( DB_SLAVE );
2431                         $res = $dbr->select(
2432                                 'protected_titles',
2433                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2434                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2435                                 __METHOD__
2436                         );
2437
2438                         // fetchRow returns false if there are no rows.
2439                         $this->mTitleProtection = $dbr->fetchRow( $res );
2440                 }
2441                 return $this->mTitleProtection;
2442         }
2443
2444         /**
2445          * Update the title protection status
2446          *
2447          * @deprecated in 1.19; use WikiPage::doUpdateRestrictions() instead.
2448          * @param $create_perm String Permission required for creation
2449          * @param string $reason Reason for protection
2450          * @param string $expiry Expiry timestamp
2451          * @return boolean true
2452          */
2453         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2454                 wfDeprecated( __METHOD__, '1.19' );
2455
2456                 global $wgUser;
2457
2458                 $limit = array( 'create' => $create_perm );
2459                 $expiry = array( 'create' => $expiry );
2460
2461                 $page = WikiPage::factory( $this );
2462                 $cascade = false;
2463                 $status = $page->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $wgUser );
2464
2465                 return $status->isOK();
2466         }
2467
2468         /**
2469          * Remove any title protection due to page existing
2470          */
2471         public function deleteTitleProtection() {
2472                 $dbw = wfGetDB( DB_MASTER );
2473
2474                 $dbw->delete(
2475                         'protected_titles',
2476                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2477                         __METHOD__
2478                 );
2479                 $this->mTitleProtection = false;
2480         }
2481
2482         /**
2483          * Is this page "semi-protected" - the *only* protection levels are listed
2484          * in $wgSemiprotectedRestrictionLevels?
2485          *
2486          * @param string $action Action to check (default: edit)
2487          * @return Bool
2488          */
2489         public function isSemiProtected( $action = 'edit' ) {
2490                 global $wgSemiprotectedRestrictionLevels;
2491
2492                 $restrictions = $this->getRestrictions( $action );
2493                 $semi = $wgSemiprotectedRestrictionLevels;
2494                 if ( !$restrictions || !$semi ) {
2495                         // Not protected, or all protection is full protection
2496                         return false;
2497                 }
2498
2499                 // Remap autoconfirmed to editsemiprotected for BC
2500                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2501                         $semi[$key] = 'editsemiprotected';
2502                 }
2503                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2504                         $restrictions[$key] = 'editsemiprotected';
2505                 }
2506
2507                 return !array_diff( $restrictions, $semi );
2508         }
2509
2510         /**
2511          * Does the title correspond to a protected article?
2512          *
2513          * @param string $action the action the page is protected from,
2514          * by default checks all actions.
2515          * @return Bool
2516          */
2517         public function isProtected( $action = '' ) {
2518                 global $wgRestrictionLevels;
2519
2520                 $restrictionTypes = $this->getRestrictionTypes();
2521
2522                 # Special pages have inherent protection
2523                 if ( $this->isSpecialPage() ) {
2524                         return true;
2525                 }
2526
2527                 # Check regular protection levels
2528                 foreach ( $restrictionTypes as $type ) {
2529                         if ( $action == $type || $action == '' ) {
2530                                 $r = $this->getRestrictions( $type );
2531                                 foreach ( $wgRestrictionLevels as $level ) {
2532                                         if ( in_array( $level, $r ) && $level != '' ) {
2533                                                 return true;
2534                                         }
2535                                 }
2536                         }
2537                 }
2538
2539                 return false;
2540         }
2541
2542         /**
2543          * Determines if $user is unable to edit this page because it has been protected
2544          * by $wgNamespaceProtection.
2545          *
2546          * @param $user User object to check permissions
2547          * @return Bool
2548          */
2549         public function isNamespaceProtected( User $user ) {
2550                 global $wgNamespaceProtection;
2551
2552                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2553                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2554                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2555                                         return true;
2556                                 }
2557                         }
2558                 }
2559                 return false;
2560         }
2561
2562         /**
2563          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2564          *
2565          * @return Bool If the page is subject to cascading restrictions.
2566          */
2567         public function isCascadeProtected() {
2568                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2569                 return ( $sources > 0 );
2570         }
2571
2572         /**
2573          * Determines whether cascading protection sources have already been loaded from
2574          * the database.
2575          *
2576          * @param bool $getPages True to check if the pages are loaded, or false to check
2577          * if the status is loaded.
2578          * @return bool Whether or not the specified information has been loaded
2579          * @since 1.23
2580          */
2581         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2582                 return $getPages ? isset( $this->mCascadeSources ) : isset( $this->mHasCascadingRestrictions );
2583         }
2584
2585         /**
2586          * Cascading protection: Get the source of any cascading restrictions on this page.
2587          *
2588          * @param bool $getPages Whether or not to retrieve the actual pages
2589          *        that the restrictions have come from.
2590          * @return Mixed Array of Title objects of the pages from which cascading restrictions
2591          *     have come, false for none, or true if such restrictions exist, but $getPages
2592          *     was not set.  The restriction array is an array of each type, each of which
2593          *     contains a array of unique groups.
2594          */
2595         public function getCascadeProtectionSources( $getPages = true ) {
2596                 global $wgContLang;
2597                 $pagerestrictions = array();
2598
2599                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2600                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2601                 } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2602                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2603                 }
2604
2605                 wfProfileIn( __METHOD__ );
2606
2607                 $dbr = wfGetDB( DB_SLAVE );
2608
2609                 if ( $this->getNamespace() == NS_FILE ) {
2610                         $tables = array( 'imagelinks', 'page_restrictions' );
2611                         $where_clauses = array(
2612                                 'il_to' => $this->getDBkey(),
2613                                 'il_from=pr_page',
2614                                 'pr_cascade' => 1
2615                         );
2616                 } else {
2617                         $tables = array( 'templatelinks', 'page_restrictions' );
2618                         $where_clauses = array(
2619                                 'tl_namespace' => $this->getNamespace(),
2620                                 'tl_title' => $this->getDBkey(),
2621                                 'tl_from=pr_page',
2622                                 'pr_cascade' => 1
2623                         );
2624                 }
2625
2626                 if ( $getPages ) {
2627                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2628                                 'pr_expiry', 'pr_type', 'pr_level' );
2629                         $where_clauses[] = 'page_id=pr_page';
2630                         $tables[] = 'page';
2631                 } else {
2632                         $cols = array( 'pr_expiry' );
2633                 }
2634
2635                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2636
2637                 $sources = $getPages ? array() : false;
2638                 $now = wfTimestampNow();
2639                 $purgeExpired = false;
2640
2641                 foreach ( $res as $row ) {
2642                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2643                         if ( $expiry > $now ) {
2644                                 if ( $getPages ) {
2645                                         $page_id = $row->pr_page;
2646                                         $page_ns = $row->page_namespace;
2647                                         $page_title = $row->page_title;
2648                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2649                                         # Add groups needed for each restriction type if its not already there
2650                                         # Make sure this restriction type still exists
2651
2652                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2653                                                 $pagerestrictions[$row->pr_type] = array();
2654                                         }
2655
2656                                         if (
2657                                                 isset( $pagerestrictions[$row->pr_type] )
2658                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2659                                         ) {
2660                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2661                                         }
2662                                 } else {
2663                                         $sources = true;
2664                                 }
2665                         } else {
2666                                 // Trigger lazy purge of expired restrictions from the db
2667                                 $purgeExpired = true;
2668                         }
2669                 }
2670                 if ( $purgeExpired ) {
2671                         Title::purgeExpiredRestrictions();
2672                 }
2673
2674                 if ( $getPages ) {
2675                         $this->mCascadeSources = $sources;
2676                         $this->mCascadingRestrictions = $pagerestrictions;
2677                 } else {
2678                         $this->mHasCascadingRestrictions = $sources;
2679                 }
2680
2681                 wfProfileOut( __METHOD__ );
2682                 return array( $sources, $pagerestrictions );
2683         }
2684
2685         /**
2686          * Accessor for mRestrictionsLoaded
2687          *
2688          * @return bool Whether or not the page's restrictions have already been
2689          * loaded from the database
2690          * @since 1.23
2691          */
2692         public function areRestrictionsLoaded() {
2693                 return $this->mRestrictionsLoaded;
2694         }
2695
2696         /**
2697          * Accessor/initialisation for mRestrictions
2698          *
2699          * @param string $action action that permission needs to be checked for
2700          * @return Array of Strings the array of groups allowed to edit this article
2701          */
2702         public function getRestrictions( $action ) {
2703                 if ( !$this->mRestrictionsLoaded ) {
2704                         $this->loadRestrictions();
2705                 }
2706                 return isset( $this->mRestrictions[$action] )
2707                                 ? $this->mRestrictions[$action]
2708                                 : array();
2709         }
2710
2711         /**
2712          * Accessor/initialisation for mRestrictions
2713          *
2714          * @return Array of Arrays of Strings the first level indexed by
2715          * action, the second level containing the names of the groups
2716          * allowed to perform each action
2717          * @since 1.23
2718          */
2719         public function getAllRestrictions() {
2720                 if ( !$this->mRestrictionsLoaded ) {
2721                         $this->loadRestrictions();
2722                 }
2723                 return $this->mRestrictions;
2724         }
2725
2726         /**
2727          * Get the expiry time for the restriction against a given action
2728          *
2729          * @param $action
2730          * @return String|Bool 14-char timestamp, or 'infinity' if the page is protected forever
2731          *     or not protected at all, or false if the action is not recognised.
2732          */
2733         public function getRestrictionExpiry( $action ) {
2734                 if ( !$this->mRestrictionsLoaded ) {
2735                         $this->loadRestrictions();
2736                 }
2737                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2738         }
2739
2740         /**
2741          * Returns cascading restrictions for the current article
2742          *
2743          * @return Boolean
2744          */
2745         function areRestrictionsCascading() {
2746                 if ( !$this->mRestrictionsLoaded ) {
2747                         $this->loadRestrictions();
2748                 }
2749
2750                 return $this->mCascadeRestriction;
2751         }
2752
2753         /**
2754          * Loads a string into mRestrictions array
2755          *
2756          * @param $res Resource restrictions as an SQL result.
2757          * @param string $oldFashionedRestrictions comma-separated list of page
2758          *        restrictions from page table (pre 1.10)
2759          */
2760         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2761                 $rows = array();
2762
2763                 foreach ( $res as $row ) {
2764                         $rows[] = $row;
2765                 }
2766
2767                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2768         }
2769
2770         /**
2771          * Compiles list of active page restrictions from both page table (pre 1.10)
2772          * and page_restrictions table for this existing page.
2773          * Public for usage by LiquidThreads.
2774          *
2775          * @param array $rows of db result objects
2776          * @param string $oldFashionedRestrictions comma-separated list of page
2777          *        restrictions from page table (pre 1.10)
2778          */
2779         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2780                 global $wgContLang;
2781                 $dbr = wfGetDB( DB_SLAVE );
2782
2783                 $restrictionTypes = $this->getRestrictionTypes();
2784
2785                 foreach ( $restrictionTypes as $type ) {
2786                         $this->mRestrictions[$type] = array();
2787                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2788                 }
2789
2790                 $this->mCascadeRestriction = false;
2791
2792                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2793
2794                 if ( $oldFashionedRestrictions === null ) {
2795                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2796                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2797                 }
2798
2799                 if ( $oldFashionedRestrictions != '' ) {
2800
2801                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2802                                 $temp = explode( '=', trim( $restrict ) );
2803                                 if ( count( $temp ) == 1 ) {
2804                                         // old old format should be treated as edit/move restriction
2805                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2806                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2807                                 } else {
2808                                         $restriction = trim( $temp[1] );
2809                                         if ( $restriction != '' ) { //some old entries are empty
2810                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2811                                         }
2812                                 }
2813                         }
2814
2815                         $this->mOldRestrictions = true;
2816
2817                 }
2818
2819                 if ( count( $rows ) ) {
2820                         # Current system - load second to make them override.
2821                         $now = wfTimestampNow();
2822                         $purgeExpired = false;
2823
2824                         # Cycle through all the restrictions.
2825                         foreach ( $rows as $row ) {
2826
2827                                 // Don't take care of restrictions types that aren't allowed
2828                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2829                                         continue;
2830                                 }
2831
2832                                 // This code should be refactored, now that it's being used more generally,
2833                                 // But I don't really see any harm in leaving it in Block for now -werdna
2834                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2835
2836                                 // Only apply the restrictions if they haven't expired!
2837                                 if ( !$expiry || $expiry > $now ) {
2838                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2839                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2840
2841                                         $this->mCascadeRestriction |= $row->pr_cascade;
2842                                 } else {
2843                                         // Trigger a lazy purge of expired restrictions
2844                                         $purgeExpired = true;
2845                                 }
2846                         }
2847
2848                         if ( $purgeExpired ) {
2849                                 Title::purgeExpiredRestrictions();
2850                         }
2851                 }
2852
2853                 $this->mRestrictionsLoaded = true;
2854         }
2855
2856         /**
2857          * Load restrictions from the page_restrictions table
2858          *
2859          * @param string $oldFashionedRestrictions comma-separated list of page
2860          *        restrictions from page table (pre 1.10)
2861          */
2862         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2863                 global $wgContLang;
2864                 if ( !$this->mRestrictionsLoaded ) {
2865                         if ( $this->exists() ) {
2866                                 $dbr = wfGetDB( DB_SLAVE );
2867
2868                                 $res = $dbr->select(
2869                                         'page_restrictions',
2870                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2871                                         array( 'pr_page' => $this->getArticleID() ),
2872                                         __METHOD__
2873                                 );
2874
2875                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2876                         } else {
2877                                 $title_protection = $this->getTitleProtection();
2878
2879                                 if ( $title_protection ) {
2880                                         $now = wfTimestampNow();
2881                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2882
2883                                         if ( !$expiry || $expiry > $now ) {
2884                                                 // Apply the restrictions
2885                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2886                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2887                                         } else { // Get rid of the old restrictions
2888                                                 Title::purgeExpiredRestrictions();
2889                                                 $this->mTitleProtection = false;
2890                                         }
2891                                 } else {
2892                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2893                                 }
2894                                 $this->mRestrictionsLoaded = true;
2895                         }
2896                 }
2897         }
2898
2899         /**
2900          * Flush the protection cache in this object and force reload from the database.
2901          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2902          */
2903         public function flushRestrictions() {
2904                 $this->mRestrictionsLoaded = false;
2905                 $this->mTitleProtection = null;
2906         }
2907
2908         /**
2909          * Purge expired restrictions from the page_restrictions table
2910          */
2911         static function purgeExpiredRestrictions() {
2912                 if ( wfReadOnly() ) {
2913                         return;
2914                 }
2915
2916                 $method = __METHOD__;
2917                 $dbw = wfGetDB( DB_MASTER );
2918                 $dbw->onTransactionIdle( function() use ( $dbw, $method ) {
2919                         $dbw->delete(
2920                                 'page_restrictions',
2921                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2922                                 $method
2923                         );
2924                         $dbw->delete(
2925                                 'protected_titles',
2926                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2927                                 $method
2928                         );
2929                 } );
2930         }
2931
2932         /**
2933          * Does this have subpages?  (Warning, usually requires an extra DB query.)
2934          *
2935          * @return Bool
2936          */
2937         public function hasSubpages() {
2938                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
2939                         # Duh
2940                         return false;
2941                 }
2942
2943                 # We dynamically add a member variable for the purpose of this method
2944                 # alone to cache the result.  There's no point in having it hanging
2945                 # around uninitialized in every Title object; therefore we only add it
2946                 # if needed and don't declare it statically.
2947                 if ( !isset( $this->mHasSubpages ) ) {
2948                         $this->mHasSubpages = false;
2949                         $subpages = $this->getSubpages( 1 );
2950                         if ( $subpages instanceof TitleArray ) {
2951                                 $this->mHasSubpages = (bool)$subpages->count();
2952                         }
2953                 }
2954
2955                 return $this->mHasSubpages;
2956         }
2957
2958         /**
2959          * Get all subpages of this page.
2960          *
2961          * @param int $limit maximum number of subpages to fetch; -1 for no limit
2962          * @return mixed TitleArray, or empty array if this page's namespace
2963          *  doesn't allow subpages
2964          */
2965         public function getSubpages( $limit = -1 ) {
2966                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
2967                         return array();
2968                 }
2969
2970                 $dbr = wfGetDB( DB_SLAVE );
2971                 $conds['page_namespace'] = $this->getNamespace();
2972                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
2973                 $options = array();
2974                 if ( $limit > -1 ) {
2975                         $options['LIMIT'] = $limit;
2976                 }
2977                 $this->mSubpages = TitleArray::newFromResult(
2978                         $dbr->select( 'page',
2979                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
2980                                 $conds,
2981                                 __METHOD__,
2982                                 $options
2983                         )
2984                 );
2985                 return $this->mSubpages;
2986         }
2987
2988         /**
2989          * Is there a version of this page in the deletion archive?
2990          *
2991          * @return Int the number of archived revisions
2992          */
2993         public function isDeleted() {
2994                 if ( $this->getNamespace() < 0 ) {
2995                         $n = 0;
2996                 } else {
2997                         $dbr = wfGetDB( DB_SLAVE );
2998
2999                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3000                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3001                                 __METHOD__
3002                         );
3003                         if ( $this->getNamespace() == NS_FILE ) {
3004                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3005                                         array( 'fa_name' => $this->getDBkey() ),
3006                                         __METHOD__
3007                                 );
3008                         }
3009                 }
3010                 return (int)$n;
3011         }
3012
3013         /**
3014          * Is there a version of this page in the deletion archive?
3015          *
3016          * @return Boolean
3017          */
3018         public function isDeletedQuick() {
3019                 if ( $this->getNamespace() < 0 ) {
3020                         return false;
3021                 }
3022                 $dbr = wfGetDB( DB_SLAVE );
3023                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3024                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3025                         __METHOD__
3026                 );
3027                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3028                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3029                                 array( 'fa_name' => $this->getDBkey() ),
3030                                 __METHOD__
3031                         );
3032                 }
3033                 return $deleted;
3034         }
3035
3036         /**
3037          * Get the article ID for this Title from the link cache,
3038          * adding it if necessary
3039          *
3040          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select
3041          *  for update
3042          * @return Int the ID
3043          */
3044         public function getArticleID( $flags = 0 ) {
3045                 if ( $this->getNamespace() < 0 ) {
3046                         $this->mArticleID = 0;
3047                         return $this->mArticleID;
3048                 }
3049                 $linkCache = LinkCache::singleton();
3050                 if ( $flags & self::GAID_FOR_UPDATE ) {
3051                         $oldUpdate = $linkCache->forUpdate( true );
3052                         $linkCache->clearLink( $this );
3053                         $this->mArticleID = $linkCache->addLinkObj( $this );
3054                         $linkCache->forUpdate( $oldUpdate );
3055                 } else {
3056                         if ( -1 == $this->mArticleID ) {
3057                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3058                         }
3059                 }
3060                 return $this->mArticleID;
3061         }
3062
3063         /**
3064          * Is this an article that is a redirect page?
3065          * Uses link cache, adding it if necessary
3066          *
3067          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3068          * @return Bool
3069          */
3070         public function isRedirect( $flags = 0 ) {
3071                 if ( !is_null( $this->mRedirect ) ) {
3072                         return $this->mRedirect;
3073                 }
3074                 # Calling getArticleID() loads the field from cache as needed
3075                 if ( !$this->getArticleID( $flags ) ) {
3076                         $this->mRedirect = false;
3077                         return $this->mRedirect;
3078                 }
3079
3080                 $linkCache = LinkCache::singleton();
3081                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3082                 if ( $cached === null ) {
3083                         # Trust LinkCache's state over our own
3084                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3085                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3086                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3087                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3088                         # LinkCache to refresh its data from the master.
3089                         $this->mRedirect = false;
3090                         return $this->mRedirect;
3091                 }
3092
3093                 $this->mRedirect = (bool)$cached;
3094
3095                 return $this->mRedirect;
3096         }
3097
3098         /**
3099          * What is the length of this page?
3100          * Uses link cache, adding it if necessary
3101          *
3102          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3103          * @return Int
3104          */
3105         public function getLength( $flags = 0 ) {
3106                 if ( $this->mLength != -1 ) {
3107                         return $this->mLength;
3108                 }
3109                 # Calling getArticleID() loads the field from cache as needed
3110                 if ( !$this->getArticleID( $flags ) ) {
3111                         $this->mLength = 0;
3112                         return $this->mLength;
3113                 }
3114                 $linkCache = LinkCache::singleton();
3115                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3116                 if ( $cached === null ) {
3117                         # Trust LinkCache's state over our own, as for isRedirect()
3118                         $this->mLength = 0;
3119                         return $this->mLength;
3120                 }
3121
3122                 $this->mLength = intval( $cached );
3123
3124                 return $this->mLength;
3125         }
3126
3127         /**
3128          * What is the page_latest field for this page?
3129          *
3130          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3131          * @return Int or 0 if the page doesn't exist
3132          */
3133         public function getLatestRevID( $flags = 0 ) {
3134                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3135                         return intval( $this->mLatestID );
3136                 }
3137                 # Calling getArticleID() loads the field from cache as needed
3138                 if ( !$this->getArticleID( $flags ) ) {
3139                         $this->mLatestID = 0;
3140                         return $this->mLatestID;
3141                 }
3142                 $linkCache = LinkCache::singleton();
3143                 $linkCache->addLinkObj( $this );
3144                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3145                 if ( $cached === null ) {
3146                         # Trust LinkCache's state over our own, as for isRedirect()
3147                         $this->mLatestID = 0;
3148                         return $this->mLatestID;
3149                 }
3150
3151                 $this->mLatestID = intval( $cached );
3152
3153                 return $this->mLatestID;
3154         }
3155
3156         /**
3157          * This clears some fields in this object, and clears any associated
3158          * keys in the "bad links" section of the link cache.
3159          *
3160          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3161          * loading of the new page_id. It's also called from
3162          * WikiPage::doDeleteArticleReal()
3163          *
3164          * @param int $newid the new Article ID
3165          */
3166         public function resetArticleID( $newid ) {
3167                 $linkCache = LinkCache::singleton();
3168                 $linkCache->clearLink( $this );
3169
3170                 if ( $newid === false ) {
3171                         $this->mArticleID = -1;
3172                 } else {
3173                         $this->mArticleID = intval( $newid );
3174                 }
3175                 $this->mRestrictionsLoaded = false;
3176                 $this->mRestrictions = array();
3177                 $this->mRedirect = null;
3178                 $this->mLength = -1;
3179                 $this->mLatestID = false;
3180                 $this->mContentModel = false;
3181                 $this->mEstimateRevisions = null;
3182                 $this->mPageLanguage = false;
3183         }
3184
3185         /**
3186          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3187          *
3188          * @param string $text containing title to capitalize
3189          * @param int $ns namespace index, defaults to NS_MAIN
3190          * @return String containing capitalized title
3191          */
3192         public static function capitalize( $text, $ns = NS_MAIN ) {
3193                 global $wgContLang;
3194
3195                 if ( MWNamespace::isCapitalized( $ns ) ) {
3196                         return $wgContLang->ucfirst( $text );
3197                 } else {
3198                         return $text;
3199                 }
3200         }
3201
3202         /**
3203          * Secure and split - main initialisation function for this object
3204          *
3205          * Assumes that mDbkeyform has been set, and is urldecoded
3206          * and uses underscores, but not otherwise munged.  This function
3207          * removes illegal characters, splits off the interwiki and
3208          * namespace prefixes, sets the other forms, and canonicalizes
3209          * everything.
3210          *
3211          * @return Bool true on success
3212          */
3213         private function secureAndSplit() {
3214                 global $wgContLang, $wgLocalInterwiki;
3215
3216                 # Initialisation
3217                 $this->mInterwiki = $this->mFragment = '';
3218                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3219
3220                 $dbkey = $this->mDbkeyform;
3221
3222                 # Strip Unicode bidi override characters.
3223                 # Sometimes they slip into cut-n-pasted page titles, where the
3224                 # override chars get included in list displays.
3225                 $dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );
3226
3227                 # Clean up whitespace
3228                 # Note: use of the /u option on preg_replace here will cause
3229                 # input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
3230                 # conveniently disabling them.
3231                 $dbkey = preg_replace( '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u', '_', $dbkey );
3232                 $dbkey = trim( $dbkey, '_' );
3233
3234                 if ( strpos( $dbkey, UTF8_REPLACEMENT ) !== false ) {
3235                         # Contained illegal UTF-8 sequences or forbidden Unicode chars.
3236                         return false;
3237                 }
3238
3239                 $this->mDbkeyform = $dbkey;
3240
3241                 # Initial colon indicates main namespace rather than specified default
3242                 # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
3243                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3244                         $this->mNamespace = NS_MAIN;
3245                         $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
3246                         $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
3247                 }
3248
3249                 if ( $dbkey == '' ) {
3250                         return false;
3251                 }
3252
3253                 # Namespace or interwiki prefix
3254                 $firstPass = true;
3255                 $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
3256                 do {
3257                         $m = array();
3258                         if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
3259                                 $p = $m[1];
3260                                 if ( ( $ns = $wgContLang->getNsIndex( $p ) ) !== false ) {
3261                                         # Ordinary namespace
3262                                         $dbkey = $m[2];
3263                                         $this->mNamespace = $ns;
3264                                         # For Talk:X pages, check if X has a "namespace" prefix
3265                                         if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
3266                                                 if ( $wgContLang->getNsIndex( $x[1] ) ) {
3267                                                         # Disallow Talk:File:x type titles...
3268                                                         return false;
3269                                                 } elseif ( Interwiki::isValidInterwiki( $x[1] ) ) {
3270                                                         # Disallow Talk:Interwiki:x type titles...
3271                                                         return false;
3272                                                 }
3273                                         }
3274                                 } elseif ( Interwiki::isValidInterwiki( $p ) ) {
3275                                         if ( !$firstPass ) {
3276                                                 # Can't make a local interwiki link to an interwiki link.
3277                                                 # That's just crazy!
3278                                                 return false;
3279                                         }
3280
3281                                         # Interwiki link
3282                                         $dbkey = $m[2];
3283                                         $this->mInterwiki = $wgContLang->lc( $p );
3284
3285                                         # Redundant interwiki prefix to the local wiki
3286                                         if ( $wgLocalInterwiki !== false
3287                                                 && 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki )
3288                                         ) {
3289                                                 if ( $dbkey == '' ) {
3290                                                         # Can't have an empty self-link
3291                                                         return false;
3292                                                 }
3293                                                 $this->mInterwiki = '';
3294                                                 $firstPass = false;
3295                                                 # Do another namespace split...
3296                                                 continue;
3297                                         }
3298
3299                                         # If there's an initial colon after the interwiki, that also
3300                                         # resets the default namespace
3301                                         if ( $dbkey !== '' && $dbkey[0] == ':' ) {
3302                                                 $this->mNamespace = NS_MAIN;
3303                                                 $dbkey = substr( $dbkey, 1 );
3304                                         }
3305                                 }
3306                                 # If there's no recognized interwiki or namespace,
3307                                 # then let the colon expression be part of the title.
3308                         }
3309                         break;
3310                 } while ( true );
3311
3312                 # We already know that some pages won't be in the database!
3313                 if ( $this->isExternal() || NS_SPECIAL == $this->mNamespace ) {
3314                         $this->mArticleID = 0;
3315                 }
3316                 $fragment = strstr( $dbkey, '#' );
3317                 if ( false !== $fragment ) {
3318                         $this->setFragment( $fragment );
3319                         $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
3320                         # remove whitespace again: prevents "Foo_bar_#"
3321                         # becoming "Foo_bar_"
3322                         $dbkey = preg_replace( '/_*$/', '', $dbkey );
3323                 }
3324
3325                 # Reject illegal characters.
3326                 $rxTc = self::getTitleInvalidRegex();
3327                 if ( preg_match( $rxTc, $dbkey ) ) {
3328                         return false;
3329                 }
3330
3331                 # Pages with "/./" or "/../" appearing in the URLs will often be un-
3332                 # reachable due to the way web browsers deal with 'relative' URLs.
3333                 # Also, they conflict with subpage syntax.  Forbid them explicitly.
3334                 if (
3335                         strpos( $dbkey, '.' ) !== false &&
3336                         (
3337                                 $dbkey === '.' || $dbkey === '..' ||
3338                                 strpos( $dbkey, './' ) === 0 ||
3339                                 strpos( $dbkey, '../' ) === 0 ||
3340                                 strpos( $dbkey, '/./' ) !== false ||
3341                                 strpos( $dbkey, '/../' ) !== false ||
3342                                 substr( $dbkey, -2 ) == '/.' ||
3343                                 substr( $dbkey, -3 ) == '/..'
3344                         )
3345                 ) {
3346                         return false;
3347                 }
3348
3349                 # Magic tilde sequences? Nu-uh!
3350                 if ( strpos( $dbkey, '~~~' ) !== false ) {
3351                         return false;
3352                 }
3353
3354                 # Limit the size of titles to 255 bytes. This is typically the size of the
3355                 # underlying database field. We make an exception for special pages, which
3356                 # don't need to be stored in the database, and may edge over 255 bytes due
3357                 # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
3358                 if (
3359                         ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 )
3360                         || strlen( $dbkey ) > 512
3361                 ) {
3362                         return false;
3363                 }
3364
3365                 # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
3366                 # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
3367                 # other site might be case-sensitive.
3368                 $this->mUserCaseDBKey = $dbkey;
3369                 if ( !$this->isExternal() ) {
3370                         $dbkey = self::capitalize( $dbkey, $this->mNamespace );
3371                 }
3372
3373                 # Can't make a link to a namespace alone... "empty" local links can only be
3374                 # self-links with a fragment identifier.
3375                 if ( $dbkey == '' && !$this->isExternal() && $this->mNamespace != NS_MAIN ) {
3376                         return false;
3377                 }
3378
3379                 // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
3380                 // IP names are not allowed for accounts, and can only be referring to
3381                 // edits from the IP. Given '::' abbreviations and caps/lowercaps,
3382                 // there are numerous ways to present the same IP. Having sp:contribs scan
3383                 // them all is silly and having some show the edits and others not is
3384                 // inconsistent. Same for talk/userpages. Keep them normalized instead.
3385                 $dbkey = ( $this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK )
3386                         ? IP::sanitizeIP( $dbkey )
3387                         : $dbkey;
3388
3389                 // Any remaining initial :s are illegal.
3390                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3391                         return false;
3392                 }
3393
3394                 # Fill fields
3395                 $this->mDbkeyform = $dbkey;
3396                 $this->mUrlform = wfUrlencode( $dbkey );
3397
3398                 $this->mTextform = str_replace( '_', ' ', $dbkey );
3399
3400                 return true;
3401         }
3402
3403         /**
3404          * Get an array of Title objects linking to this Title
3405          * Also stores the IDs in the link cache.
3406          *
3407          * WARNING: do not use this function on arbitrary user-supplied titles!
3408          * On heavily-used templates it will max out the memory.
3409          *
3410          * @param array $options may be FOR UPDATE
3411          * @param string $table table name
3412          * @param string $prefix fields prefix
3413          * @return Array of Title objects linking here
3414          */
3415         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3416                 if ( count( $options ) > 0 ) {
3417                         $db = wfGetDB( DB_MASTER );
3418                 } else {
3419                         $db = wfGetDB( DB_SLAVE );
3420                 }
3421
3422                 $res = $db->select(
3423                         array( 'page', $table ),
3424                         self::getSelectFields(),
3425                         array(
3426                                 "{$prefix}_from=page_id",
3427                                 "{$prefix}_namespace" => $this->getNamespace(),
3428                                 "{$prefix}_title" => $this->getDBkey() ),
3429                         __METHOD__,
3430                         $options
3431                 );
3432
3433                 $retVal = array();
3434                 if ( $res->numRows() ) {
3435                         $linkCache = LinkCache::singleton();
3436                         foreach ( $res as $row ) {
3437                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3438                                 if ( $titleObj ) {
3439                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3440                                         $retVal[] = $titleObj;
3441                                 }
3442                         }
3443                 }
3444                 return $retVal;
3445         }
3446
3447         /**
3448          * Get an array of Title objects using this Title as a template
3449          * Also stores the IDs in the link cache.
3450          *
3451          * WARNING: do not use this function on arbitrary user-supplied titles!
3452          * On heavily-used templates it will max out the memory.
3453          *
3454          * @param array $options may be FOR UPDATE
3455          * @return Array of Title the Title objects linking here
3456          */
3457         public function getTemplateLinksTo( $options = array() ) {
3458                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3459         }
3460
3461         /**
3462          * Get an array of Title objects linked from this Title
3463          * Also stores the IDs in the link cache.
3464          *
3465          * WARNING: do not use this function on arbitrary user-supplied titles!
3466          * On heavily-used templates it will max out the memory.
3467          *
3468          * @param array $options may be FOR UPDATE
3469          * @param string $table table name
3470          * @param string $prefix fields prefix
3471          * @return Array of Title objects linking here
3472          */
3473         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3474                 global $wgContentHandlerUseDB;
3475
3476                 $id = $this->getArticleID();
3477
3478                 # If the page doesn't exist; there can't be any link from this page
3479                 if ( !$id ) {
3480                         return array();
3481                 }
3482
3483                 if ( count( $options ) > 0 ) {
3484                         $db = wfGetDB( DB_MASTER );
3485                 } else {
3486                         $db = wfGetDB( DB_SLAVE );
3487                 }
3488
3489                 $namespaceFiled = "{$prefix}_namespace";
3490                 $titleField = "{$prefix}_title";
3491
3492                 $fields = array( $namespaceFiled, $titleField, 'page_id', 'page_len', 'page_is_redirect', 'page_latest' );
3493                 if ( $wgContentHandlerUseDB ) {
3494                         $fields[] = 'page_content_model';
3495                 }
3496
3497                 $res = $db->select(
3498                         array( $table, 'page' ),
3499                         $fields,
3500                         array( "{$prefix}_from" => $id ),
3501                         __METHOD__,
3502                         $options,
3503                         array( 'page' => array( 'LEFT JOIN', array( "page_namespace=$namespaceFiled", "page_title=$titleField" ) ) )
3504                 );
3505
3506                 $retVal = array();
3507                 if ( $res->numRows() ) {
3508                         $linkCache = LinkCache::singleton();
3509                         foreach ( $res as $row ) {
3510                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3511                                 if ( $titleObj ) {
3512                                         if ( $row->page_id ) {
3513                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3514                                         } else {
3515                                                 $linkCache->addBadLinkObj( $titleObj );
3516                                         }
3517                                         $retVal[] = $titleObj;
3518                                 }
3519                         }
3520                 }
3521                 return $retVal;
3522         }
3523
3524         /**
3525          * Get an array of Title objects used on this Title as a template
3526          * Also stores the IDs in the link cache.
3527          *
3528          * WARNING: do not use this function on arbitrary user-supplied titles!
3529          * On heavily-used templates it will max out the memory.
3530          *
3531          * @param array $options may be FOR UPDATE
3532          * @return Array of Title the Title objects used here
3533          */
3534         public function getTemplateLinksFrom( $options = array() ) {
3535                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3536         }
3537
3538         /**
3539          * Get an array of Title objects referring to non-existent articles linked from this page
3540          *
3541          * @todo check if needed (used only in SpecialBrokenRedirects.php, and should use redirect table in this case)
3542          * @return Array of Title the Title objects
3543          */
3544         public function getBrokenLinksFrom() {
3545                 if ( $this->getArticleID() == 0 ) {
3546                         # All links from article ID 0 are false positives
3547                         return array();
3548                 }
3549
3550                 $dbr = wfGetDB( DB_SLAVE );
3551                 $res = $dbr->select(
3552                         array( 'page', 'pagelinks' ),
3553                         array( 'pl_namespace', 'pl_title' ),
3554                         array(
3555                                 'pl_from' => $this->getArticleID(),
3556                                 'page_namespace IS NULL'
3557                         ),
3558                         __METHOD__, array(),
3559                         array(
3560                                 'page' => array(
3561                                         'LEFT JOIN',
3562                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3563                                 )
3564                         )
3565                 );
3566
3567                 $retVal = array();
3568                 foreach ( $res as $row ) {
3569                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3570                 }
3571                 return $retVal;
3572         }
3573
3574         /**
3575          * Get a list of URLs to purge from the Squid cache when this
3576          * page changes
3577          *
3578          * @return Array of String the URLs
3579          */
3580         public function getSquidURLs() {
3581                 $urls = array(
3582                         $this->getInternalURL(),
3583                         $this->getInternalURL( 'action=history' )
3584                 );
3585
3586                 $pageLang = $this->getPageLanguage();
3587                 if ( $pageLang->hasVariants() ) {
3588                         $variants = $pageLang->getVariants();
3589                         foreach ( $variants as $vCode ) {
3590                                 $urls[] = $this->getInternalURL( '', $vCode );
3591                         }
3592                 }
3593
3594                 // If we are looking at a css/js user subpage, purge the action=raw.
3595                 if ( $this->isJsSubpage() ) {
3596                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3597                 } elseif ( $this->isCssSubpage() ) {
3598                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3599                 }
3600
3601                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3602                 return $urls;
3603         }
3604
3605         /**
3606          * Purge all applicable Squid URLs
3607          */
3608         public function purgeSquid() {
3609                 global $wgUseSquid;
3610                 if ( $wgUseSquid ) {
3611                         $urls = $this->getSquidURLs();
3612                         $u = new SquidUpdate( $urls );
3613                         $u->doUpdate();
3614                 }
3615         }
3616
3617         /**
3618          * Move this page without authentication
3619          *
3620          * @param $nt Title the new page Title
3621          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3622          */
3623         public function moveNoAuth( &$nt ) {
3624                 return $this->moveTo( $nt, false );
3625         }
3626
3627         /**
3628          * Check whether a given move operation would be valid.
3629          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3630          *
3631          * @param $nt Title the new title
3632          * @param bool $auth indicates whether $wgUser's permissions
3633          *  should be checked
3634          * @param string $reason is the log summary of the move, used for spam checking
3635          * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
3636          */
3637         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3638                 global $wgUser, $wgContentHandlerUseDB;
3639
3640                 $errors = array();
3641                 if ( !$nt ) {
3642                         // Normally we'd add this to $errors, but we'll get
3643                         // lots of syntax errors if $nt is not an object
3644                         return array( array( 'badtitletext' ) );
3645                 }
3646                 if ( $this->equals( $nt ) ) {
3647                         $errors[] = array( 'selfmove' );
3648                 }
3649                 if ( !$this->isMovable() ) {
3650                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3651                 }
3652                 if ( $nt->isExternal() ) {
3653                         $errors[] = array( 'immobile-target-namespace-iw' );
3654                 }
3655                 if ( !$nt->isMovable() ) {
3656                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3657                 }
3658
3659                 $oldid = $this->getArticleID();
3660                 $newid = $nt->getArticleID();
3661
3662                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3663                         $errors[] = array( 'articleexists' );
3664                 }
3665                 if (
3666                         ( $this->getDBkey() == '' ) ||
3667                         ( !$oldid ) ||
3668                         ( $nt->getDBkey() == '' )
3669                 ) {
3670                         $errors[] = array( 'badarticleerror' );
3671                 }
3672
3673                 // Content model checks
3674                 if ( !$wgContentHandlerUseDB &&
3675                                 $this->getContentModel() !== $nt->getContentModel() ) {
3676                         // can't move a page if that would change the page's content model
3677                         $errors[] = array(
3678                                 'bad-target-model',
3679                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3680                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3681                         );
3682                 }
3683
3684                 // Image-specific checks
3685                 if ( $this->getNamespace() == NS_FILE ) {
3686                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3687                 }
3688
3689                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3690                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3691                 }
3692
3693                 if ( $auth ) {
3694                         $errors = wfMergeErrorArrays( $errors,
3695                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3696                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3697                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3698                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3699                 }
3700
3701                 $match = EditPage::matchSummarySpamRegex( $reason );
3702                 if ( $match !== false ) {
3703                         // This is kind of lame, won't display nice
3704                         $errors[] = array( 'spamprotectiontext' );
3705                 }
3706
3707                 $err = null;
3708                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3709                         $errors[] = array( 'hookaborted', $err );
3710                 }
3711
3712                 # The move is allowed only if (1) the target doesn't exist, or
3713                 # (2) the target is a redirect to the source, and has no history
3714                 # (so we can undo bad moves right after they're done).
3715
3716                 if ( 0 != $newid ) { # Target exists; check for validity
3717                         if ( !$this->isValidMoveTarget( $nt ) ) {
3718                                 $errors[] = array( 'articleexists' );
3719                         }
3720                 } else {
3721                         $tp = $nt->getTitleProtection();
3722                         $right = $tp['pt_create_perm'];
3723                         if ( $right == 'sysop' ) {
3724                                 $right = 'editprotected'; // B/C
3725                         }
3726                         if ( $right == 'autoconfirmed' ) {
3727                                 $right = 'editsemiprotected'; // B/C
3728                         }
3729                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3730                                 $errors[] = array( 'cantmove-titleprotected' );
3731                         }
3732                 }
3733                 if ( empty( $errors ) ) {
3734                         return true;
3735                 }
3736                 return $errors;
3737         }
3738
3739         /**
3740          * Check if the requested move target is a valid file move target
3741          * @param Title $nt Target title
3742          * @return array List of errors
3743          */
3744         protected function validateFileMoveOperation( $nt ) {
3745                 global $wgUser;
3746
3747                 $errors = array();
3748
3749                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3750
3751                 $file = wfLocalFile( $this );
3752                 if ( $file->exists() ) {
3753                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3754                                 $errors[] = array( 'imageinvalidfilename' );
3755                         }
3756                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3757                                 $errors[] = array( 'imagetypemismatch' );
3758                         }
3759                 }
3760
3761                 if ( $nt->getNamespace() != NS_FILE ) {
3762                         $errors[] = array( 'imagenocrossnamespace' );
3763                         // From here we want to do checks on a file object, so if we can't
3764                         // create one, we must return.
3765                         return $errors;
3766                 }
3767
3768                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3769
3770                 $destFile = wfLocalFile( $nt );
3771                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3772                         $errors[] = array( 'file-exists-sharedrepo' );
3773                 }
3774
3775                 return $errors;
3776         }
3777
3778         /**
3779          * Move a title to a new location
3780          *
3781          * @param $nt Title the new title
3782          * @param bool $auth indicates whether $wgUser's permissions
3783          *  should be checked
3784          * @param string $reason the reason for the move
3785          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3786          *  Ignored if the user doesn't have the suppressredirect right.
3787          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3788          */
3789         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3790                 global $wgUser;
3791                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3792                 if ( is_array( $err ) ) {
3793                         // Auto-block user's IP if the account was "hard" blocked
3794                         $wgUser->spreadAnyEditBlock();
3795                         return $err;
3796                 }
3797                 // Check suppressredirect permission
3798                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3799                         $createRedirect = true;
3800                 }
3801
3802                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3803
3804                 // If it is a file, move it first.
3805                 // It is done before all other moving stuff is done because it's hard to revert.
3806                 $dbw = wfGetDB( DB_MASTER );
3807                 if ( $this->getNamespace() == NS_FILE ) {
3808                         $file = wfLocalFile( $this );
3809                         if ( $file->exists() ) {
3810                                 $status = $file->move( $nt );
3811                                 if ( !$status->isOk() ) {
3812                                         return $status->getErrorsArray();
3813                                 }
3814                         }
3815                         // Clear RepoGroup process cache
3816                         RepoGroup::singleton()->clearCache( $this );
3817                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3818                 }
3819
3820                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3821                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3822                 $protected = $this->isProtected();
3823
3824                 // Do the actual move
3825                 $this->moveToInternal( $nt, $reason, $createRedirect );
3826
3827                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3828                 // cl_timestamp, which may disturb time-based lists on some sites.
3829                 $prefixes = $dbw->select(
3830                         'categorylinks',
3831                         array( 'cl_sortkey_prefix', 'cl_to' ),
3832                         array( 'cl_from' => $pageid ),
3833                         __METHOD__
3834                 );
3835                 foreach ( $prefixes as $prefixRow ) {
3836                         $prefix = $prefixRow->cl_sortkey_prefix;
3837                         $catTo = $prefixRow->cl_to;
3838                         $dbw->update( 'categorylinks',
3839                                 array(
3840                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3841                                                 $nt->getCategorySortkey( $prefix ) ),
3842                                         'cl_timestamp=cl_timestamp' ),
3843                                 array(
3844                                         'cl_from' => $pageid,
3845                                         'cl_to' => $catTo ),
3846                                 __METHOD__
3847                         );
3848                 }
3849
3850                 $redirid = $this->getArticleID();
3851
3852                 if ( $protected ) {
3853                         # Protect the redirect title as the title used to be...
3854                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3855                                 array(
3856                                         'pr_page' => $redirid,
3857                                         'pr_type' => 'pr_type',
3858                                         'pr_level' => 'pr_level',
3859                                         'pr_cascade' => 'pr_cascade',
3860                                         'pr_user' => 'pr_user',
3861                                         'pr_expiry' => 'pr_expiry'
3862                                 ),
3863                                 array( 'pr_page' => $pageid ),
3864                                 __METHOD__,
3865                                 array( 'IGNORE' )
3866                         );
3867                         # Update the protection log
3868                         $log = new LogPage( 'protect' );
3869                         $comment = wfMessage(
3870                                 'prot_1movedto2',
3871                                 $this->getPrefixedText(),
3872                                 $nt->getPrefixedText()
3873                         )->inContentLanguage()->text();
3874                         if ( $reason ) {
3875                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3876                         }
3877                         // @todo FIXME: $params?
3878                         $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ), $wgUser );
3879                 }
3880
3881                 # Update watchlists
3882                 $oldnamespace = MWNamespace::getSubject( $this->getNamespace() );
3883                 $newnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3884                 $oldtitle = $this->getDBkey();
3885                 $newtitle = $nt->getDBkey();
3886
3887                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3888                         WatchedItem::duplicateEntries( $this, $nt );
3889                 }
3890
3891                 $dbw->commit( __METHOD__ );
3892
3893                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
3894                 return true;
3895         }
3896
3897         /**
3898          * Move page to a title which is either a redirect to the
3899          * source page or nonexistent
3900          *
3901          * @param $nt Title the page to move to, which should be a redirect or nonexistent
3902          * @param string $reason The reason for the move
3903          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3904          *   if the user has the suppressredirect right
3905          * @throws MWException
3906          */
3907         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3908                 global $wgUser, $wgContLang;
3909
3910                 if ( $nt->exists() ) {
3911                         $moveOverRedirect = true;
3912                         $logType = 'move_redir';
3913                 } else {
3914                         $moveOverRedirect = false;
3915                         $logType = 'move';
3916                 }
3917
3918                 if ( $createRedirect ) {
3919                         $contentHandler = ContentHandler::getForTitle( $this );
3920                         $redirectContent = $contentHandler->makeRedirectContent( $nt,
3921                                 wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3922
3923                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3924                 } else {
3925                         $redirectContent = null;
3926                 }
3927
3928                 $logEntry = new ManualLogEntry( 'move', $logType );
3929                 $logEntry->setPerformer( $wgUser );
3930                 $logEntry->setTarget( $this );
3931                 $logEntry->setComment( $reason );
3932                 $logEntry->setParameters( array(
3933                         '4::target' => $nt->getPrefixedText(),
3934                         '5::noredir' => $redirectContent ? '0': '1',
3935                 ) );
3936
3937                 $formatter = LogFormatter::newFromEntry( $logEntry );
3938                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3939                 $comment = $formatter->getPlainActionText();
3940                 if ( $reason ) {
3941                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3942                 }
3943                 # Truncate for whole multibyte characters.
3944                 $comment = $wgContLang->truncate( $comment, 255 );
3945
3946                 $oldid = $this->getArticleID();
3947
3948                 $dbw = wfGetDB( DB_MASTER );
3949
3950                 $newpage = WikiPage::factory( $nt );
3951
3952                 if ( $moveOverRedirect ) {
3953                         $newid = $nt->getArticleID();
3954                         $newcontent = $newpage->getContent();
3955
3956                         # Delete the old redirect. We don't save it to history since
3957                         # by definition if we've got here it's rather uninteresting.
3958                         # We have to remove it so that the next step doesn't trigger
3959                         # a conflict on the unique namespace+title index...
3960                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3961
3962                         $newpage->doDeleteUpdates( $newid, $newcontent );
3963                 }
3964
3965                 # Save a null revision in the page's history notifying of the move
3966                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
3967                 if ( !is_object( $nullRevision ) ) {
3968                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3969                 }
3970
3971                 $nullRevision->insertOn( $dbw );
3972
3973                 # Change the name of the target page:
3974                 $dbw->update( 'page',
3975                         /* SET */ array(
3976                                 'page_namespace' => $nt->getNamespace(),
3977                                 'page_title' => $nt->getDBkey(),
3978                         ),
3979                         /* WHERE */ array( 'page_id' => $oldid ),
3980                         __METHOD__
3981                 );
3982
3983                 // clean up the old title before reset article id - bug 45348
3984                 if ( !$redirectContent ) {
3985                         WikiPage::onArticleDelete( $this );
3986                 }
3987
3988                 $this->resetArticleID( 0 ); // 0 == non existing
3989                 $nt->resetArticleID( $oldid );
3990                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
3991
3992                 $newpage->updateRevisionOn( $dbw, $nullRevision );
3993
3994                 wfRunHooks( 'NewRevisionFromEditComplete',
3995                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
3996
3997                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
3998
3999                 if ( !$moveOverRedirect ) {
4000                         WikiPage::onArticleCreate( $nt );
4001                 }
4002
4003                 # Recreate the redirect, this time in the other direction.
4004                 if ( $redirectContent ) {
4005                         $redirectArticle = WikiPage::factory( $this );
4006                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
4007                         $newid = $redirectArticle->insertOn( $dbw );
4008                         if ( $newid ) { // sanity
4009                                 $this->resetArticleID( $newid );
4010                                 $redirectRevision = new Revision( array(
4011                                         'title' => $this, // for determining the default content model
4012                                         'page' => $newid,
4013                                         'comment' => $comment,
4014                                         'content' => $redirectContent ) );
4015                                 $redirectRevision->insertOn( $dbw );
4016                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
4017
4018                                 wfRunHooks( 'NewRevisionFromEditComplete',
4019                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
4020
4021                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
4022                         }
4023                 }
4024
4025                 # Log the move
4026                 $logid = $logEntry->insert();
4027                 $logEntry->publish( $logid );
4028         }
4029
4030         /**
4031          * Move this page's subpages to be subpages of $nt
4032          *
4033          * @param $nt Title Move target
4034          * @param bool $auth Whether $wgUser's permissions should be checked
4035          * @param string $reason The reason for the move
4036          * @param bool $createRedirect Whether to create redirects from the old subpages to
4037          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
4038          * @return mixed array with old page titles as keys, and strings (new page titles) or
4039          *     arrays (errors) as values, or an error array with numeric indices if no pages
4040          *     were moved
4041          */
4042         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
4043                 global $wgMaximumMovedPages;
4044                 // Check permissions
4045                 if ( !$this->userCan( 'move-subpages' ) ) {
4046                         return array( 'cant-move-subpages' );
4047                 }
4048                 // Do the source and target namespaces support subpages?
4049                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4050                         return array( 'namespace-nosubpages',
4051                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
4052                 }
4053                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
4054                         return array( 'namespace-nosubpages',
4055                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
4056                 }
4057
4058                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
4059                 $retval = array();
4060                 $count = 0;
4061                 foreach ( $subpages as $oldSubpage ) {
4062                         $count++;
4063                         if ( $count > $wgMaximumMovedPages ) {
4064                                 $retval[$oldSubpage->getPrefixedTitle()] =
4065                                                 array( 'movepage-max-pages',
4066                                                         $wgMaximumMovedPages );
4067                                 break;
4068                         }
4069
4070                         // We don't know whether this function was called before
4071                         // or after moving the root page, so check both
4072                         // $this and $nt
4073                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4074                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4075                         ) {
4076                                 // When moving a page to a subpage of itself,
4077                                 // don't move it twice
4078                                 continue;
4079                         }
4080                         $newPageName = preg_replace(
4081                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4082                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4083                                         $oldSubpage->getDBkey() );
4084                         if ( $oldSubpage->isTalkPage() ) {
4085                                 $newNs = $nt->getTalkPage()->getNamespace();
4086                         } else {
4087                                 $newNs = $nt->getSubjectPage()->getNamespace();
4088                         }
4089                         # Bug 14385: we need makeTitleSafe because the new page names may
4090                         # be longer than 255 characters.
4091                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4092
4093                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4094                         if ( $success === true ) {
4095                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4096                         } else {
4097                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4098                         }
4099                 }
4100                 return $retval;
4101         }
4102
4103         /**
4104          * Checks if this page is just a one-rev redirect.
4105          * Adds lock, so don't use just for light purposes.
4106          *
4107          * @return Bool
4108          */
4109         public function isSingleRevRedirect() {
4110                 global $wgContentHandlerUseDB;
4111
4112                 $dbw = wfGetDB( DB_MASTER );
4113
4114                 # Is it a redirect?
4115                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4116                 if ( $wgContentHandlerUseDB ) {
4117                         $fields[] = 'page_content_model';
4118                 }
4119
4120                 $row = $dbw->selectRow( 'page',
4121                         $fields,
4122                         $this->pageCond(),
4123                         __METHOD__,
4124                         array( 'FOR UPDATE' )
4125                 );
4126                 # Cache some fields we may want
4127                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4128                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4129                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4130                 $this->mContentModel = $row && isset( $row->page_content_model ) ? strval( $row->page_content_model ) : false;
4131                 if ( !$this->mRedirect ) {
4132                         return false;
4133                 }
4134                 # Does the article have a history?
4135                 $row = $dbw->selectField( array( 'page', 'revision' ),
4136                         'rev_id',
4137                         array( 'page_namespace' => $this->getNamespace(),
4138                                 'page_title' => $this->getDBkey(),
4139                                 'page_id=rev_page',
4140                                 'page_latest != rev_id'
4141                         ),
4142                         __METHOD__,
4143                         array( 'FOR UPDATE' )
4144                 );
4145                 # Return true if there was no history
4146                 return ( $row === false );
4147         }
4148
4149         /**
4150          * Checks if $this can be moved to a given Title
4151          * - Selects for update, so don't call it unless you mean business
4152          *
4153          * @param $nt Title the new title to check
4154          * @return Bool
4155          */
4156         public function isValidMoveTarget( $nt ) {
4157                 # Is it an existing file?
4158                 if ( $nt->getNamespace() == NS_FILE ) {
4159                         $file = wfLocalFile( $nt );
4160                         if ( $file->exists() ) {
4161                                 wfDebug( __METHOD__ . ": file exists\n" );
4162                                 return false;
4163                         }
4164                 }
4165                 # Is it a redirect with no history?
4166                 if ( !$nt->isSingleRevRedirect() ) {
4167                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4168                         return false;
4169                 }
4170                 # Get the article text
4171                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4172                 if ( !is_object( $rev ) ) {
4173                         return false;
4174                 }
4175                 $content = $rev->getContent();
4176                 # Does the redirect point to the source?
4177                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4178                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4179
4180                 if ( $redirTitle ) {
4181                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4182                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4183                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4184                                 return false;
4185                         } else {
4186                                 return true;
4187                         }
4188                 } else {
4189                         # Fail safe (not a redirect after all. strange.)
4190                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4191                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4192                         return false;
4193                 }
4194         }
4195
4196         /**
4197          * Get categories to which this Title belongs and return an array of
4198          * categories' names.
4199          *
4200          * @return Array of parents in the form:
4201          *        $parent => $currentarticle
4202          */
4203         public function getParentCategories() {
4204                 global $wgContLang;
4205
4206                 $data = array();
4207
4208                 $titleKey = $this->getArticleID();
4209
4210                 if ( $titleKey === 0 ) {
4211                         return $data;
4212                 }
4213
4214                 $dbr = wfGetDB( DB_SLAVE );
4215
4216                 $res = $dbr->select(
4217                         'categorylinks',
4218                         'cl_to',
4219                         array( 'cl_from' => $titleKey ),
4220                         __METHOD__
4221                 );
4222
4223                 if ( $res->numRows() > 0 ) {
4224                         foreach ( $res as $row ) {
4225                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4226                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4227                         }
4228                 }
4229                 return $data;
4230         }
4231
4232         /**
4233          * Get a tree of parent categories
4234          *
4235          * @param array $children with the children in the keys, to check for circular refs
4236          * @return Array Tree of parent categories
4237          */
4238         public function getParentCategoryTree( $children = array() ) {
4239                 $stack = array();
4240                 $parents = $this->getParentCategories();
4241
4242                 if ( $parents ) {
4243                         foreach ( $parents as $parent => $current ) {
4244                                 if ( array_key_exists( $parent, $children ) ) {
4245                                         # Circular reference
4246                                         $stack[$parent] = array();
4247                                 } else {
4248                                         $nt = Title::newFromText( $parent );
4249                                         if ( $nt ) {
4250                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4251                                         }
4252                                 }
4253                         }
4254                 }
4255
4256                 return $stack;
4257         }
4258
4259         /**
4260          * Get an associative array for selecting this title from
4261          * the "page" table
4262          *
4263          * @return Array suitable for the $where parameter of DB::select()
4264          */
4265         public function pageCond() {
4266                 if ( $this->mArticleID > 0 ) {
4267                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4268                         return array( 'page_id' => $this->mArticleID );
4269                 } else {
4270                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4271                 }
4272         }
4273
4274         /**
4275          * Get the revision ID of the previous revision
4276          *
4277          * @param int $revId Revision ID. Get the revision that was before this one.
4278          * @param int $flags Title::GAID_FOR_UPDATE
4279          * @return Int|Bool Old revision ID, or FALSE if none exists
4280          */
4281         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4282                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4283                 $revId = $db->selectField( 'revision', 'rev_id',
4284                         array(
4285                                 'rev_page' => $this->getArticleID( $flags ),
4286                                 'rev_id < ' . intval( $revId )
4287                         ),
4288                         __METHOD__,
4289                         array( 'ORDER BY' => 'rev_id DESC' )
4290                 );
4291
4292                 if ( $revId === false ) {
4293                         return false;
4294                 } else {
4295                         return intval( $revId );
4296                 }
4297         }
4298
4299         /**
4300          * Get the revision ID of the next revision
4301          *
4302          * @param int $revId Revision ID. Get the revision that was after this one.
4303          * @param int $flags Title::GAID_FOR_UPDATE
4304          * @return Int|Bool Next revision ID, or FALSE if none exists
4305          */
4306         public function getNextRevisionID( $revId, $flags = 0 ) {
4307                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4308                 $revId = $db->selectField( 'revision', 'rev_id',
4309                         array(
4310                                 'rev_page' => $this->getArticleID( $flags ),
4311                                 'rev_id > ' . intval( $revId )
4312                         ),
4313                         __METHOD__,
4314                         array( 'ORDER BY' => 'rev_id' )
4315                 );
4316
4317                 if ( $revId === false ) {
4318                         return false;
4319                 } else {
4320                         return intval( $revId );
4321                 }
4322         }
4323
4324         /**
4325          * Get the first revision of the page
4326          *
4327          * @param int $flags Title::GAID_FOR_UPDATE
4328          * @return Revision|Null if page doesn't exist
4329          */
4330         public function getFirstRevision( $flags = 0 ) {
4331                 $pageId = $this->getArticleID( $flags );
4332                 if ( $pageId ) {
4333                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4334                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4335                                 array( 'rev_page' => $pageId ),
4336                                 __METHOD__,
4337                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4338                         );
4339                         if ( $row ) {
4340                                 return new Revision( $row );
4341                         }
4342                 }
4343                 return null;
4344         }
4345
4346         /**
4347          * Get the oldest revision timestamp of this page
4348          *
4349          * @param int $flags Title::GAID_FOR_UPDATE
4350          * @return String: MW timestamp
4351          */
4352         public function getEarliestRevTime( $flags = 0 ) {
4353                 $rev = $this->getFirstRevision( $flags );
4354                 return $rev ? $rev->getTimestamp() : null;
4355         }
4356
4357         /**
4358          * Check if this is a new page
4359          *
4360          * @return bool
4361          */
4362         public function isNewPage() {
4363                 $dbr = wfGetDB( DB_SLAVE );
4364                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4365         }
4366
4367         /**
4368          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4369          *
4370          * @return bool
4371          */
4372         public function isBigDeletion() {
4373                 global $wgDeleteRevisionsLimit;
4374
4375                 if ( !$wgDeleteRevisionsLimit ) {
4376                         return false;
4377                 }
4378
4379                 $revCount = $this->estimateRevisionCount();
4380                 return $revCount > $wgDeleteRevisionsLimit;
4381         }
4382
4383         /**
4384          * Get the  approximate revision count of this page.
4385          *
4386          * @return int
4387          */
4388         public function estimateRevisionCount() {
4389                 if ( !$this->exists() ) {
4390                         return 0;
4391                 }
4392
4393                 if ( $this->mEstimateRevisions === null ) {
4394                         $dbr = wfGetDB( DB_SLAVE );
4395                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4396                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4397                 }
4398
4399                 return $this->mEstimateRevisions;
4400         }
4401
4402         /**
4403          * Get the number of revisions between the given revision.
4404          * Used for diffs and other things that really need it.
4405          *
4406          * @param int|Revision $old Old revision or rev ID (first before range)
4407          * @param int|Revision $new New revision or rev ID (first after range)
4408          * @return Int Number of revisions between these revisions.
4409          */
4410         public function countRevisionsBetween( $old, $new ) {
4411                 if ( !( $old instanceof Revision ) ) {
4412                         $old = Revision::newFromTitle( $this, (int)$old );
4413                 }
4414                 if ( !( $new instanceof Revision ) ) {
4415                         $new = Revision::newFromTitle( $this, (int)$new );
4416                 }
4417                 if ( !$old || !$new ) {
4418                         return 0; // nothing to compare
4419                 }
4420                 $dbr = wfGetDB( DB_SLAVE );
4421                 return (int)$dbr->selectField( 'revision', 'count(*)',
4422                         array(
4423                                 'rev_page' => $this->getArticleID(),
4424                                 'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4425                                 'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4426                         ),
4427                         __METHOD__
4428                 );
4429         }
4430
4431         /**
4432          * Get the number of authors between the given revisions or revision IDs.
4433          * Used for diffs and other things that really need it.
4434          *
4435          * @param int|Revision $old Old revision or rev ID (first before range by default)
4436          * @param int|Revision $new New revision or rev ID (first after range by default)
4437          * @param int $limit Maximum number of authors
4438          * @param string|array $options (Optional): Single option, or an array of options:
4439          *     'include_old' Include $old in the range; $new is excluded.
4440          *     'include_new' Include $new in the range; $old is excluded.
4441          *     'include_both' Include both $old and $new in the range.
4442          *     Unknown option values are ignored.
4443          * @return int Number of revision authors in the range; zero if not both revisions exist
4444          */
4445         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4446                 if ( !( $old instanceof Revision ) ) {
4447                         $old = Revision::newFromTitle( $this, (int)$old );
4448                 }
4449                 if ( !( $new instanceof Revision ) ) {
4450                         $new = Revision::newFromTitle( $this, (int)$new );
4451                 }
4452                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4453                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4454                 // in the sanity check below?
4455                 if ( !$old || !$new ) {
4456                         return 0; // nothing to compare
4457                 }
4458                 $old_cmp = '>';
4459                 $new_cmp = '<';
4460                 $options = (array)$options;
4461                 if ( in_array( 'include_old', $options ) ) {
4462                         $old_cmp = '>=';
4463                 }
4464                 if ( in_array( 'include_new', $options ) ) {
4465                         $new_cmp = '<=';
4466                 }
4467                 if ( in_array( 'include_both', $options ) ) {
4468                         $old_cmp = '>=';
4469                         $new_cmp = '<=';
4470                 }
4471                 // No DB query needed if $old and $new are the same or successive revisions:
4472                 if ( $old->getId() === $new->getId() ) {
4473                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4474                 } elseif ( $old->getId() === $new->getParentId() ) {
4475                         if ( $old_cmp === '>' || $new_cmp === '<' ) {
4476                                 return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4477                         }
4478                         return ( $old->getRawUserText() === $new->getRawUserText() ) ? 1 : 2;
4479                 }
4480                 $dbr = wfGetDB( DB_SLAVE );
4481                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4482                         array(
4483                                 'rev_page' => $this->getArticleID(),
4484                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4485                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4486                         ), __METHOD__,
4487                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4488                 );
4489                 return (int)$dbr->numRows( $res );
4490         }
4491
4492         /**
4493          * Compare with another title.
4494          *
4495          * @param $title Title
4496          * @return Bool
4497          */
4498         public function equals( Title $title ) {
4499                 // Note: === is necessary for proper matching of number-like titles.
4500                 return $this->getInterwiki() === $title->getInterwiki()
4501                         && $this->getNamespace() == $title->getNamespace()
4502                         && $this->getDBkey() === $title->getDBkey();
4503         }
4504
4505         /**
4506          * Check if this title is a subpage of another title
4507          *
4508          * @param $title Title
4509          * @return Bool
4510          */
4511         public function isSubpageOf( Title $title ) {
4512                 return $this->getInterwiki() === $title->getInterwiki()
4513                         && $this->getNamespace() == $title->getNamespace()
4514                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4515         }
4516
4517         /**
4518          * Check if page exists.  For historical reasons, this function simply
4519          * checks for the existence of the title in the page table, and will
4520          * thus return false for interwiki links, special pages and the like.
4521          * If you want to know if a title can be meaningfully viewed, you should
4522          * probably call the isKnown() method instead.
4523          *
4524          * @return Bool
4525          */
4526         public function exists() {
4527                 return $this->getArticleID() != 0;
4528         }
4529
4530         /**
4531          * Should links to this title be shown as potentially viewable (i.e. as
4532          * "bluelinks"), even if there's no record by this title in the page
4533          * table?
4534          *
4535          * This function is semi-deprecated for public use, as well as somewhat
4536          * misleadingly named.  You probably just want to call isKnown(), which
4537          * calls this function internally.
4538          *
4539          * (ISSUE: Most of these checks are cheap, but the file existence check
4540          * can potentially be quite expensive.  Including it here fixes a lot of
4541          * existing code, but we might want to add an optional parameter to skip
4542          * it and any other expensive checks.)
4543          *
4544          * @return Bool
4545          */
4546         public function isAlwaysKnown() {
4547                 $isKnown = null;
4548
4549                 /**
4550                  * Allows overriding default behavior for determining if a page exists.
4551                  * If $isKnown is kept as null, regular checks happen. If it's
4552                  * a boolean, this value is returned by the isKnown method.
4553                  *
4554                  * @since 1.20
4555                  *
4556                  * @param Title $title
4557                  * @param boolean|null $isKnown
4558                  */
4559                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4560
4561                 if ( !is_null( $isKnown ) ) {
4562                         return $isKnown;
4563                 }
4564
4565                 if ( $this->isExternal() ) {
4566                         return true;  // any interwiki link might be viewable, for all we know
4567                 }
4568
4569                 switch ( $this->mNamespace ) {
4570                         case NS_MEDIA:
4571                         case NS_FILE:
4572                                 // file exists, possibly in a foreign repo
4573                                 return (bool)wfFindFile( $this );
4574                         case NS_SPECIAL:
4575                                 // valid special page
4576                                 return SpecialPageFactory::exists( $this->getDBkey() );
4577                         case NS_MAIN:
4578                                 // selflink, possibly with fragment
4579                                 return $this->mDbkeyform == '';
4580                         case NS_MEDIAWIKI:
4581                                 // known system message
4582                                 return $this->hasSourceText() !== false;
4583                         default:
4584                                 return false;
4585                 }
4586         }
4587
4588         /**
4589          * Does this title refer to a page that can (or might) be meaningfully
4590          * viewed?  In particular, this function may be used to determine if
4591          * links to the title should be rendered as "bluelinks" (as opposed to
4592          * "redlinks" to non-existent pages).
4593          * Adding something else to this function will cause inconsistency
4594          * since LinkHolderArray calls isAlwaysKnown() and does its own
4595          * page existence check.
4596          *
4597          * @return Bool
4598          */
4599         public function isKnown() {
4600                 return $this->isAlwaysKnown() || $this->exists();
4601         }
4602
4603         /**
4604          * Does this page have source text?
4605          *
4606          * @return Boolean
4607          */
4608         public function hasSourceText() {
4609                 if ( $this->exists() ) {
4610                         return true;
4611                 }
4612
4613                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4614                         // If the page doesn't exist but is a known system message, default
4615                         // message content will be displayed, same for language subpages-
4616                         // Use always content language to avoid loading hundreds of languages
4617                         // to get the link color.
4618                         global $wgContLang;
4619                         list( $name, ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4620                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4621                         return $message->exists();
4622                 }
4623
4624                 return false;
4625         }
4626
4627         /**
4628          * Get the default message text or false if the message doesn't exist
4629          *
4630          * @return String or false
4631          */
4632         public function getDefaultMessageText() {
4633                 global $wgContLang;
4634
4635                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4636                         return false;
4637                 }
4638
4639                 list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4640                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4641
4642                 if ( $message->exists() ) {
4643                         return $message->plain();
4644                 } else {
4645                         return false;
4646                 }
4647         }
4648
4649         /**
4650          * Updates page_touched for this page; called from LinksUpdate.php
4651          *
4652          * @return Bool true if the update succeeded
4653          */
4654         public function invalidateCache() {
4655                 if ( wfReadOnly() ) {
4656                         return false;
4657                 }
4658
4659                 $method = __METHOD__;
4660                 $dbw = wfGetDB( DB_MASTER );
4661                 $conds = $this->pageCond();
4662                 $dbw->onTransactionIdle( function() use ( $dbw, $conds, $method ) {
4663                         $dbw->update(
4664                                 'page',
4665                                 array( 'page_touched' => $dbw->timestamp() ),
4666                                 $conds,
4667                                 $method
4668                         );
4669                 } );
4670
4671                 return true;
4672         }
4673
4674         /**
4675          * Update page_touched timestamps and send squid purge messages for
4676          * pages linking to this title. May be sent to the job queue depending
4677          * on the number of links. Typically called on create and delete.
4678          */
4679         public function touchLinks() {
4680                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4681                 $u->doUpdate();
4682
4683                 if ( $this->getNamespace() == NS_CATEGORY ) {
4684                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4685                         $u->doUpdate();
4686                 }
4687         }
4688
4689         /**
4690          * Get the last touched timestamp
4691          *
4692          * @param $db DatabaseBase: optional db
4693          * @return String last-touched timestamp
4694          */
4695         public function getTouched( $db = null ) {
4696                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
4697                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4698                 return $touched;
4699         }
4700
4701         /**
4702          * Get the timestamp when this page was updated since the user last saw it.
4703          *
4704          * @param $user User
4705          * @return String|Null
4706          */
4707         public function getNotificationTimestamp( $user = null ) {
4708                 global $wgUser, $wgShowUpdatedMarker;
4709                 // Assume current user if none given
4710                 if ( !$user ) {
4711                         $user = $wgUser;
4712                 }
4713                 // Check cache first
4714                 $uid = $user->getId();
4715                 // avoid isset here, as it'll return false for null entries
4716                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4717                         return $this->mNotificationTimestamp[$uid];
4718                 }
4719                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4720                         $this->mNotificationTimestamp[$uid] = false;
4721                         return $this->mNotificationTimestamp[$uid];
4722                 }
4723                 // Don't cache too much!
4724                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4725                         $this->mNotificationTimestamp = array();
4726                 }
4727                 $dbr = wfGetDB( DB_SLAVE );
4728                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4729                         'wl_notificationtimestamp',
4730                         array(
4731                                 'wl_user' => $user->getId(),
4732                                 'wl_namespace' => $this->getNamespace(),
4733                                 'wl_title' => $this->getDBkey(),
4734                         ),
4735                         __METHOD__
4736                 );
4737                 return $this->mNotificationTimestamp[$uid];
4738         }
4739
4740         /**
4741          * Generate strings used for xml 'id' names in monobook tabs
4742          *
4743          * @param string $prepend defaults to 'nstab-'
4744          * @return String XML 'id' name
4745          */
4746         public function getNamespaceKey( $prepend = 'nstab-' ) {
4747                 global $wgContLang;
4748                 // Gets the subject namespace if this title
4749                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4750                 // Checks if canonical namespace name exists for namespace
4751                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4752                         // Uses canonical namespace name
4753                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4754                 } else {
4755                         // Uses text of namespace
4756                         $namespaceKey = $this->getSubjectNsText();
4757                 }
4758                 // Makes namespace key lowercase
4759                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4760                 // Uses main
4761                 if ( $namespaceKey == '' ) {
4762                         $namespaceKey = 'main';
4763                 }
4764                 // Changes file to image for backwards compatibility
4765                 if ( $namespaceKey == 'file' ) {
4766                         $namespaceKey = 'image';
4767                 }
4768                 return $prepend . $namespaceKey;
4769         }
4770
4771         /**
4772          * Get all extant redirects to this Title
4773          *
4774          * @param int|Null $ns Single namespace to consider; NULL to consider all namespaces
4775          * @return Title[] Array of Title redirects to this title
4776          */
4777         public function getRedirectsHere( $ns = null ) {
4778                 $redirs = array();
4779
4780                 $dbr = wfGetDB( DB_SLAVE );
4781                 $where = array(
4782                         'rd_namespace' => $this->getNamespace(),
4783                         'rd_title' => $this->getDBkey(),
4784                         'rd_from = page_id'
4785                 );
4786                 if ( $this->isExternal() ) {
4787                         $where['rd_interwiki'] = $this->getInterwiki();
4788                 } else {
4789                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4790                 }
4791                 if ( !is_null( $ns ) ) {
4792                         $where['page_namespace'] = $ns;
4793                 }
4794
4795                 $res = $dbr->select(
4796                         array( 'redirect', 'page' ),
4797                         array( 'page_namespace', 'page_title' ),
4798                         $where,
4799                         __METHOD__
4800                 );
4801
4802                 foreach ( $res as $row ) {
4803                         $redirs[] = self::newFromRow( $row );
4804                 }
4805                 return $redirs;
4806         }
4807
4808         /**
4809          * Check if this Title is a valid redirect target
4810          *
4811          * @return Bool
4812          */
4813         public function isValidRedirectTarget() {
4814                 global $wgInvalidRedirectTargets;
4815
4816                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4817                 if ( $this->isSpecial( 'Userlogout' ) ) {
4818                         return false;
4819                 }
4820
4821                 foreach ( $wgInvalidRedirectTargets as $target ) {
4822                         if ( $this->isSpecial( $target ) ) {
4823                                 return false;
4824                         }
4825                 }
4826
4827                 return true;
4828         }
4829
4830         /**
4831          * Get a backlink cache object
4832          *
4833          * @return BacklinkCache
4834          */
4835         public function getBacklinkCache() {
4836                 return BacklinkCache::get( $this );
4837         }
4838
4839         /**
4840          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4841          *
4842          * @return Boolean
4843          */
4844         public function canUseNoindex() {
4845                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4846
4847                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4848                         ? $wgContentNamespaces
4849                         : $wgExemptFromUserRobotsControl;
4850
4851                 return !in_array( $this->mNamespace, $bannedNamespaces );
4852
4853         }
4854
4855         /**
4856          * Returns the raw sort key to be used for categories, with the specified
4857          * prefix.  This will be fed to Collation::getSortKey() to get a
4858          * binary sortkey that can be used for actual sorting.
4859          *
4860          * @param string $prefix The prefix to be used, specified using
4861          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4862          *   prefix.
4863          * @return string
4864          */
4865         public function getCategorySortkey( $prefix = '' ) {
4866                 $unprefixed = $this->getText();
4867
4868                 // Anything that uses this hook should only depend
4869                 // on the Title object passed in, and should probably
4870                 // tell the users to run updateCollations.php --force
4871                 // in order to re-sort existing category relations.
4872                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4873                 if ( $prefix !== '' ) {
4874                         # Separate with a line feed, so the unprefixed part is only used as
4875                         # a tiebreaker when two pages have the exact same prefix.
4876                         # In UCA, tab is the only character that can sort above LF
4877                         # so we strip both of them from the original prefix.
4878                         $prefix = strtr( $prefix, "\n\t", '  ' );
4879                         return "$prefix\n$unprefixed";
4880                 }
4881                 return $unprefixed;
4882         }
4883
4884         /**
4885          * Get the language in which the content of this page is written in
4886          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4887          * e.g. $wgLang (such as special pages, which are in the user language).
4888          *
4889          * @since 1.18
4890          * @return Language
4891          */
4892         public function getPageLanguage() {
4893                 global $wgLang, $wgLanguageCode;
4894                 wfProfileIn( __METHOD__ );
4895                 if ( $this->isSpecialPage() ) {
4896                         // special pages are in the user language
4897                         wfProfileOut( __METHOD__ );
4898                         return $wgLang;
4899                 }
4900
4901                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4902                         // Note that this may depend on user settings, so the cache should be only per-request.
4903                         // NOTE: ContentHandler::getPageLanguage() may need to load the content to determine the page language!
4904                         // Checking $wgLanguageCode hasn't changed for the benefit of unit tests.
4905                         $contentHandler = ContentHandler::getForTitle( $this );
4906                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4907                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4908                 } else {
4909                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4910                 }
4911                 wfProfileOut( __METHOD__ );
4912                 return $langObj;
4913         }
4914
4915         /**
4916          * Get the language in which the content of this page is written when
4917          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4918          * e.g. $wgLang (such as special pages, which are in the user language).
4919          *
4920          * @since 1.20
4921          * @return Language
4922          */
4923         public function getPageViewLanguage() {
4924                 global $wgLang;
4925
4926                 if ( $this->isSpecialPage() ) {
4927                         // If the user chooses a variant, the content is actually
4928                         // in a language whose code is the variant code.
4929                         $variant = $wgLang->getPreferredVariant();
4930                         if ( $wgLang->getCode() !== $variant ) {
4931                                 return Language::factory( $variant );
4932                         }
4933
4934                         return $wgLang;
4935                 }
4936
4937                 //NOTE: can't be cached persistently, depends on user settings
4938                 //NOTE: ContentHandler::getPageViewLanguage() may need to load the content to determine the page language!
4939                 $contentHandler = ContentHandler::getForTitle( $this );
4940                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4941                 return $pageLang;
4942         }
4943
4944         /**
4945          * Get a list of rendered edit notices for this page.
4946          *
4947          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4948          * they will already be wrapped in paragraphs.
4949          *
4950          * @since 1.21
4951          * @param int oldid Revision ID that's being edited
4952          * @return Array
4953          */
4954         public function getEditNotices( $oldid = 0 ) {
4955                 $notices = array();
4956
4957                 # Optional notices on a per-namespace and per-page basis
4958                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4959                 $editnotice_ns_message = wfMessage( $editnotice_ns );
4960                 if ( $editnotice_ns_message->exists() ) {
4961                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
4962                 }
4963                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4964                         $parts = explode( '/', $this->getDBkey() );
4965                         $editnotice_base = $editnotice_ns;
4966                         while ( count( $parts ) > 0 ) {
4967                                 $editnotice_base .= '-' . array_shift( $parts );
4968                                 $editnotice_base_msg = wfMessage( $editnotice_base );
4969                                 if ( $editnotice_base_msg->exists() ) {
4970                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
4971                                 }
4972                         }
4973                 } else {
4974                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
4975                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
4976                         $editnoticeMsg = wfMessage( $editnoticeText );
4977                         if ( $editnoticeMsg->exists() ) {
4978                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
4979                         }
4980                 }
4981
4982                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4983                 return $notices;
4984         }
4985 }