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         /** @name Static cache variables */
  35         // @{
  36         static private $titleCache = array();
  37         // @}
  38
  39         /**
  40          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  41          * commonly used titles. On a batch operation this can become a memory leak
  42          * if not bounded. After hitting this many titles reset the cache.
  43          */
  44         const CACHE_MAX = 1000;
  45
  46         /**
  47          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  48          * to use the master DB
  49          */
  50         const GAID_FOR_UPDATE = 1;
  51
  52         /**
  53          * @name Private member variables
  54          * Please use the accessor functions instead.
  55          * @private
  56          */
  57         // @{
  58
  59         var $mTextform = '';              // /< Text form (spaces not underscores) of the main part
  60         var $mUrlform = '';               // /< URL-encoded form of the main part
  61         var $mDbkeyform = '';             // /< Main part with underscores
  62         var $mUserCaseDBKey;              // /< DB key with the initial letter in the case specified by the user
  63         var $mNamespace = NS_MAIN;        // /< Namespace index, i.e. one of the NS_xxxx constants
  64         var $mInterwiki = '';             // /< Interwiki prefix (or null string)
  65         var $mFragment;                   // /< Title fragment (i.e. the bit after the #)
  66         var $mArticleID = -1;             // /< Article ID, fetched from the link cache on demand
  67         var $mLatestID = false;           // /< ID of most recent revision
  68         var $mContentModel = false;       // /< ID of the page's content model, i.e. one of the CONTENT_MODEL_XXX constants
  69         private $mEstimateRevisions;      // /< Estimated number of revisions; null of not loaded
  70         var $mRestrictions = array();     // /< Array of groups allowed to edit this article
  71         var $mOldRestrictions = false;
  72         var $mCascadeRestriction;         ///< Cascade restrictions on this page to included templates and images?
  73         var $mCascadingRestrictions;      // Caching the results of getCascadeProtectionSources
  74         var $mRestrictionsExpiry = array(); ///< When do the restrictions on this page expire?
  75         var $mHasCascadingRestrictions;   ///< Are cascading restrictions in effect on this page?
  76         var $mCascadeSources;             ///< Where are the cascading restrictions coming from on this page?
  77         var $mRestrictionsLoaded = false; ///< Boolean for initialisation on demand
  78         var $mPrefixedText;               ///< Text form including namespace/interwiki, initialised on demand
  79         var $mTitleProtection;            ///< Cached value for getTitleProtection (create protection)
  80         # Don't change the following default, NS_MAIN is hardcoded in several
  81         # places.  See bug 696.
  82         var $mDefaultNamespace = NS_MAIN; // /< Namespace index when there is no namespace
  83                                                                           # Zero except in {{transclusion}} tags
  84         var $mWatched = null;             // /< Is $wgUser watching this page? null if unfilled, accessed through userIsWatching()
  85         var $mLength = -1;                // /< The page length, 0 for special pages
  86         var $mRedirect = null;            // /< Is the article at this title a redirect?
  87         var $mNotificationTimestamp = array(); // /< Associative array of user ID -> timestamp/false
  88         var $mHasSubpage;                 // /< Whether a page has any subpages
  89         private $mPageLanguage = false;   // /< The (string) language code of the page's language and content code.
  90         // @}
  91
  92         /**
  93          * Constructor
  94          */
  95         /*protected*/ function __construct() { }
  96
  97         /**
  98          * Create a new Title from a prefixed DB key
  99          *
 100          * @param string $key the database key, which has underscores
 101          *      instead of spaces, possibly including namespace and
 102          *      interwiki prefixes
 103          * @return Title, or NULL on an error
 104          */
 105         public static function newFromDBkey( $key ) {
 106                 $t = new Title();
 107                 $t->mDbkeyform = $key;
 108                 if ( $t->secureAndSplit() ) {
 109                         return $t;
 110                 } else {
 111                         return null;
 112                 }
 113         }
 114
 115         /**
 116          * Create a new Title from text, such as what one would find in a link. De-
 117          * codes any HTML entities in the text.
 118          *
 119          * @param string $text the link text; spaces, prefixes, and an
 120          *   initial ':' indicating the main namespace are accepted.
 121          * @param int $defaultNamespace the namespace to use if none is specified
 122          *   by a prefix.  If you want to force a specific namespace even if
 123          *   $text might begin with a namespace prefix, use makeTitle() or
 124          *   makeTitleSafe().
 125          * @throws MWException
 126          * @return Title|null - Title or null on an error.
 127          */
 128         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 129                 if ( is_object( $text ) ) {
 130                         throw new MWException( 'Title::newFromText given an object' );
 131                 }
 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 ( $defaultNamespace == NS_MAIN && isset( Title::$titleCache[$text] ) ) {
 142                         return Title::$titleCache[$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                 static $cachedcount = 0;
 153                 if ( $t->secureAndSplit() ) {
 154                         if ( $defaultNamespace == NS_MAIN ) {
 155                                 if ( $cachedcount >= self::CACHE_MAX ) {
 156                                         # Avoid memory leaks on mass operations...
 157                                         Title::$titleCache = array();
 158                                         $cachedcount = 0;
 159                                 }
 160                                 $cachedcount++;
 161                                 Title::$titleCache[$text] =& $t;
 162                         }
 163                         return $t;
 164                 } else {
 165                         $ret = null;
 166                         return $ret;
 167                 }
 168         }
 169
 170         /**
 171          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 172          *
 173          * Example of wrong and broken code:
 174          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 175          *
 176          * Example of right code:
 177          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 178          *
 179          * Create a new Title from URL-encoded text. Ensures that
 180          * the given title's length does not exceed the maximum.
 181          *
 182          * @param string $url the title, as might be taken from a URL
 183          * @return Title the new object, or NULL on an error
 184          */
 185         public static function newFromURL( $url ) {
 186                 $t = new Title();
 187
 188                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 189                 # but some URLs used it as a space replacement and they still come
 190                 # from some external search tools.
 191                 if ( strpos( self::legalChars(), '+' ) === false ) {
 192                         $url = str_replace( '+', ' ', $url );
 193                 }
 194
 195                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 196                 if ( $t->secureAndSplit() ) {
 197                         return $t;
 198                 } else {
 199                         return null;
 200                 }
 201         }
 202
 203         /**
 204          * Returns a list of fields that are to be selected for initializing Title objects or LinkCache entries.
 205          * Uses $wgContentHandlerUseDB to determine whether to include page_content_model.
 206          *
 207          * @return array
 208          */
 209         protected static function getSelectFields() {
 210                 global $wgContentHandlerUseDB;
 211
 212                 $fields = array(
 213                         'page_namespace', 'page_title', 'page_id',
 214                         'page_len', 'page_is_redirect', 'page_latest',
 215                 );
 216
 217                 if ( $wgContentHandlerUseDB ) {
 218                         $fields[] = 'page_content_model';
 219                 }
 220
 221                 return $fields;
 222         }
 223
 224         /**
 225          * Create a new Title from an article ID
 226          *
 227          * @param int $id the page_id corresponding to the Title to create
 228          * @param int $flags use Title::GAID_FOR_UPDATE to use master
 229          * @return Title|null the new object, or NULL on an error
 230          */
 231         public static function newFromID( $id, $flags = 0 ) {
 232                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 233                 $row = $db->selectRow(
 234                         'page',
 235                         self::getSelectFields(),
 236                         array( 'page_id' => $id ),
 237                         __METHOD__
 238                 );
 239                 if ( $row !== false ) {
 240                         $title = Title::newFromRow( $row );
 241                 } else {
 242                         $title = null;
 243                 }
 244                 return $title;
 245         }
 246
 247         /**
 248          * Make an array of titles from an array of IDs
 249          *
 250          * @param array $ids of Int Array of IDs
 251          * @return Array of Titles
 252          */
 253         public static function newFromIDs( $ids ) {
 254                 if ( !count( $ids ) ) {
 255                         return array();
 256                 }
 257                 $dbr = wfGetDB( DB_SLAVE );
 258
 259                 $res = $dbr->select(
 260                         'page',
 261                         self::getSelectFields(),
 262                         array( 'page_id' => $ids ),
 263                         __METHOD__
 264                 );
 265
 266                 $titles = array();
 267                 foreach ( $res as $row ) {
 268                         $titles[] = Title::newFromRow( $row );
 269                 }
 270                 return $titles;
 271         }
 272
 273         /**
 274          * Make a Title object from a DB row
 275          *
 276          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 277          * @return Title corresponding Title
 278          */
 279         public static function newFromRow( $row ) {
 280                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 281                 $t->loadFromRow( $row );
 282                 return $t;
 283         }
 284
 285         /**
 286          * Load Title object fields from a DB row.
 287          * If false is given, the title will be treated as non-existing.
 288          *
 289          * @param $row stdClass|bool database row
 290          */
 291         public function loadFromRow( $row ) {
 292                 if ( $row ) { // page found
 293                         if ( isset( $row->page_id ) ) {
 294                                 $this->mArticleID = (int)$row->page_id;
 295                         }
 296                         if ( isset( $row->page_len ) ) {
 297                                 $this->mLength = (int)$row->page_len;
 298                         }
 299                         if ( isset( $row->page_is_redirect ) ) {
 300                                 $this->mRedirect = (bool)$row->page_is_redirect;
 301                         }
 302                         if ( isset( $row->page_latest ) ) {
 303                                 $this->mLatestID = (int)$row->page_latest;
 304                         }
 305                         if ( isset( $row->page_content_model ) ) {
 306                                 $this->mContentModel = strval( $row->page_content_model );
 307                         } else {
 308                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 309                         }
 310                 } else { // page not found
 311                         $this->mArticleID = 0;
 312                         $this->mLength = 0;
 313                         $this->mRedirect = false;
 314                         $this->mLatestID = 0;
 315                         $this->mContentModel = false; # initialized lazily in getContentModel()
 316                 }
 317         }
 318
 319         /**
 320          * Create a new Title from a namespace index and a DB key.
 321          * It's assumed that $ns and $title are *valid*, for instance when
 322          * they came directly from the database or a special page name.
 323          * For convenience, spaces are converted to underscores so that
 324          * eg user_text fields can be used directly.
 325          *
 326          * @param int $ns the namespace of the article
 327          * @param string $title the unprefixed database key form
 328          * @param string $fragment the link fragment (after the "#")
 329          * @param string $interwiki the interwiki prefix
 330          * @return Title the new object
 331          */
 332         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 333                 $t = new Title();
 334                 $t->mInterwiki = $interwiki;
 335                 $t->mFragment = $fragment;
 336                 $t->mNamespace = $ns = intval( $ns );
 337                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 338                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 339                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 340                 $t->mTextform = str_replace( '_', ' ', $title );
 341                 $t->mContentModel = false; # initialized lazily in getContentModel()
 342                 return $t;
 343         }
 344
 345         /**
 346          * Create a new Title from a namespace index and a DB key.
 347          * The parameters will be checked for validity, which is a bit slower
 348          * than makeTitle() but safer for user-provided data.
 349          *
 350          * @param int $ns the namespace of the article
 351          * @param string $title database key form
 352          * @param string $fragment the link fragment (after the "#")
 353          * @param string $interwiki interwiki prefix
 354          * @return Title the new object, or NULL on an error
 355          */
 356         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 357                 if ( !MWNamespace::exists( $ns ) ) {
 358                         return null;
 359                 }
 360
 361                 $t = new Title();
 362                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 363                 if ( $t->secureAndSplit() ) {
 364                         return $t;
 365                 } else {
 366                         return null;
 367                 }
 368         }
 369
 370         /**
 371          * Create a new Title for the Main Page
 372          *
 373          * @return Title the new object
 374          */
 375         public static function newMainPage() {
 376                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 377                 // Don't give fatal errors if the message is broken
 378                 if ( !$title ) {
 379                         $title = Title::newFromText( 'Main Page' );
 380                 }
 381                 return $title;
 382         }
 383
 384         /**
 385          * Extract a redirect destination from a string and return the
 386          * Title, or null if the text doesn't contain a valid redirect
 387          * This will only return the very next target, useful for
 388          * the redirect table and other checks that don't need full recursion
 389          *
 390          * @param string $text Text with possible redirect
 391          * @return Title: The corresponding Title
 392          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 393          */
 394         public static function newFromRedirect( $text ) {
 395                 ContentHandler::deprecated( __METHOD__, '1.21' );
 396
 397                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 398                 return $content->getRedirectTarget();
 399         }
 400
 401         /**
 402          * Extract a redirect destination from a string and return the
 403          * Title, or null if the text doesn't contain a valid redirect
 404          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 405          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 406          *
 407          * @param string $text Text with possible redirect
 408          * @return Title
 409          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 410          */
 411         public static function newFromRedirectRecurse( $text ) {
 412                 ContentHandler::deprecated( __METHOD__, '1.21' );
 413
 414                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 415                 return $content->getUltimateRedirectTarget();
 416         }
 417
 418         /**
 419          * Extract a redirect destination from a string and return an
 420          * array of Titles, or null if the text doesn't contain a valid redirect
 421          * The last element in the array is the final destination after all redirects
 422          * have been resolved (up to $wgMaxRedirects times)
 423          *
 424          * @param string $text Text with possible redirect
 425          * @return Array of Titles, with the destination last
 426          * @deprecated since 1.21, use Content::getRedirectChain instead.
 427          */
 428         public static function newFromRedirectArray( $text ) {
 429                 ContentHandler::deprecated( __METHOD__, '1.21' );
 430
 431                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 432                 return $content->getRedirectChain();
 433         }
 434
 435         /**
 436          * Get the prefixed DB key associated with an ID
 437          *
 438          * @param int $id the page_id of the article
 439          * @return Title an object representing the article, or NULL if no such article was found
 440          */
 441         public static function nameOf( $id ) {
 442                 $dbr = wfGetDB( DB_SLAVE );
 443
 444                 $s = $dbr->selectRow(
 445                         'page',
 446                         array( 'page_namespace', 'page_title' ),
 447                         array( 'page_id' => $id ),
 448                         __METHOD__
 449                 );
 450                 if ( $s === false ) {
 451                         return null;
 452                 }
 453
 454                 $n = self::makeName( $s->page_namespace, $s->page_title );
 455                 return $n;
 456         }
 457
 458         /**
 459          * Get a regex character class describing the legal characters in a link
 460          *
 461          * @return String the list of characters, not delimited
 462          */
 463         public static function legalChars() {
 464                 global $wgLegalTitleChars;
 465                 return $wgLegalTitleChars;
 466         }
 467
 468         /**
 469          * Returns a simple regex that will match on characters and sequences invalid in titles.
 470          * Note that this doesn't pick up many things that could be wrong with titles, but that
 471          * replacing this regex with something valid will make many titles valid.
 472          *
 473          * @return String regex string
 474          */
 475         static function getTitleInvalidRegex() {
 476                 static $rxTc = false;
 477                 if ( !$rxTc ) {
 478                         # Matching titles will be held as illegal.
 479                         $rxTc = '/' .
 480                                 # Any character not allowed is forbidden...
 481                                 '[^' . self::legalChars() . ']' .
 482                                 # URL percent encoding sequences interfere with the ability
 483                                 # to round-trip titles -- you can't link to them consistently.
 484                                 '|%[0-9A-Fa-f]{2}' .
 485                                 # XML/HTML character references produce similar issues.
 486                                 '|&[A-Za-z0-9\x80-\xff]+;' .
 487                                 '|&#[0-9]+;' .
 488                                 '|&#x[0-9A-Fa-f]+;' .
 489                                 '/S';
 490                 }
 491
 492                 return $rxTc;
 493         }
 494
 495         /**
 496          * Utility method for converting a character sequence from bytes to Unicode.
 497          *
 498          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 499          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 500          *
 501          * @param string $byteClass
 502          * @return string
 503          */
 504         public static function convertByteClassToUnicodeClass( $byteClass ) {
 505                 $length = strlen( $byteClass );
 506                 // Input token queue
 507                 $x0 = $x1 = $x2 = '';
 508                 // Decoded queue
 509                 $d0 = $d1 = $d2 = '';
 510                 // Decoded integer codepoints
 511                 $ord0 = $ord1 = $ord2 = 0;
 512                 // Re-encoded queue
 513                 $r0 = $r1 = $r2 = '';
 514                 // Output
 515                 $out = '';
 516                 // Flags
 517                 $allowUnicode = false;
 518                 for ( $pos = 0; $pos < $length; $pos++ ) {
 519                         // Shift the queues down
 520                         $x2 = $x1;
 521                         $x1 = $x0;
 522                         $d2 = $d1;
 523                         $d1 = $d0;
 524                         $ord2 = $ord1;
 525                         $ord1 = $ord0;
 526                         $r2 = $r1;
 527                         $r1 = $r0;
 528                         // Load the current input token and decoded values
 529                         $inChar = $byteClass[$pos];
 530                         if ( $inChar == '\\' ) {
 531                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 532                                         $x0 = $inChar . $m[0];
 533                                         $d0 = chr( hexdec( $m[1] ) );
 534                                         $pos += strlen( $m[0] );
 535                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 536                                         $x0 = $inChar . $m[0];
 537                                         $d0 = chr( octdec( $m[0] ) );
 538                                         $pos += strlen( $m[0] );
 539                                 } elseif ( $pos + 1 >= $length ) {
 540                                         $x0 = $d0 = '\\';
 541                                 } else {
 542                                         $d0 = $byteClass[$pos + 1];
 543                                         $x0 = $inChar . $d0;
 544                                         $pos += 1;
 545                                 }
 546                         } else {
 547                                 $x0 = $d0 = $inChar;
 548                         }
 549                         $ord0 = ord( $d0 );
 550                         // Load the current re-encoded value
 551                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 552                                 $r0 = sprintf( '\x%02x', $ord0 );
 553                         } elseif ( $ord0 >= 0x80 ) {
 554                                 // Allow unicode if a single high-bit character appears
 555                                 $r0 = sprintf( '\x%02x', $ord0 );
 556                                 $allowUnicode = true;
 557                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 558                                 $r0 = '\\' . $d0;
 559                         } else {
 560                                 $r0 = $d0;
 561                         }
 562                         // Do the output
 563                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 564                                 // Range
 565                                 if ( $ord2 > $ord0 ) {
 566                                         // Empty range
 567                                 } elseif ( $ord0 >= 0x80 ) {
 568                                         // Unicode range
 569                                         $allowUnicode = true;
 570                                         if ( $ord2 < 0x80 ) {
 571                                                 // Keep the non-unicode section of the range
 572                                                 $out .= "$r2-\\x7F";
 573                                         }
 574                                 } else {
 575                                         // Normal range
 576                                         $out .= "$r2-$r0";
 577                                 }
 578                                 // Reset state to the initial value
 579                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 580                         } elseif ( $ord2 < 0x80 ) {
 581                                 // ASCII character
 582                                 $out .= $r2;
 583                         }
 584                 }
 585                 if ( $ord1 < 0x80 ) {
 586                         $out .= $r1;
 587                 }
 588                 if ( $ord0 < 0x80 ) {
 589                         $out .= $r0;
 590                 }
 591                 if ( $allowUnicode ) {
 592                         $out .= '\u0080-\uFFFF';
 593                 }
 594                 return $out;
 595         }
 596
 597         /**
 598          * Get a string representation of a title suitable for
 599          * including in a search index
 600          *
 601          * @param int $ns a namespace index
 602          * @param string $title text-form main part
 603          * @return String a stripped-down title string ready for the search index
 604          */
 605         public static function indexTitle( $ns, $title ) {
 606                 global $wgContLang;
 607
 608                 $lc = SearchEngine::legalSearchChars() . '&#;';
 609                 $t = $wgContLang->normalizeForSearch( $title );
 610                 $t = preg_replace( "/[^{$lc}]+/", ' ', $t );
 611                 $t = $wgContLang->lc( $t );
 612
 613                 # Handle 's, s'
 614                 $t = preg_replace( "/([{$lc}]+)'s( |$)/", "\\1 \\1's ", $t );
 615                 $t = preg_replace( "/([{$lc}]+)s'( |$)/", "\\1s ", $t );
 616
 617                 $t = preg_replace( "/\\s+/", ' ', $t );
 618
 619                 if ( $ns == NS_FILE ) {
 620                         $t = preg_replace( "/ (png|gif|jpg|jpeg|ogg)$/", "", $t );
 621                 }
 622                 return trim( $t );
 623         }
 624
 625         /**
 626          * Make a prefixed DB key from a DB key and a namespace index
 627          *
 628          * @param int $ns numerical representation of the namespace
 629          * @param string $title the DB key form the title
 630          * @param string $fragment The link fragment (after the "#")
 631          * @param string $interwiki The interwiki prefix
 632          * @return String the prefixed form of the title
 633          */
 634         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 635                 global $wgContLang;
 636
 637                 $namespace = $wgContLang->getNsText( $ns );
 638                 $name = $namespace == '' ? $title : "$namespace:$title";
 639                 if ( strval( $interwiki ) != '' ) {
 640                         $name = "$interwiki:$name";
 641                 }
 642                 if ( strval( $fragment ) != '' ) {
 643                         $name .= '#' . $fragment;
 644                 }
 645                 return $name;
 646         }
 647
 648         /**
 649          * Escape a text fragment, say from a link, for a URL
 650          *
 651          * @param string $fragment containing a URL or link fragment (after the "#")
 652          * @return String: escaped string
 653          */
 654         static function escapeFragmentForURL( $fragment ) {
 655                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 656                 # fragments appear not to work in IE (at least up to 7) or in at least
 657                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 658                 # to care if they aren't encoded.
 659                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 660         }
 661
 662         /**
 663          * Callback for usort() to do title sorts by (namespace, title)
 664          *
 665          * @param $a Title
 666          * @param $b Title
 667          *
 668          * @return Integer: result of string comparison, or namespace comparison
 669          */
 670         public static function compare( $a, $b ) {
 671                 if ( $a->getNamespace() == $b->getNamespace() ) {
 672                         return strcmp( $a->getText(), $b->getText() );
 673                 } else {
 674                         return $a->getNamespace() - $b->getNamespace();
 675                 }
 676         }
 677
 678         /**
 679          * Determine whether the object refers to a page within
 680          * this project.
 681          *
 682          * @return Bool TRUE if this is an in-project interwiki link or a wikilink, FALSE otherwise
 683          */
 684         public function isLocal() {
 685                 if ( $this->mInterwiki != '' ) {
 686                         $iw = Interwiki::fetch( $this->mInterwiki );
 687                         if ( $iw ) {
 688                                 return $iw->isLocal();
 689                         }
 690                 }
 691                 return true;
 692         }
 693
 694         /**
 695          * Is this Title interwiki?
 696          *
 697          * @return Bool
 698          */
 699         public function isExternal() {
 700                 return ( $this->mInterwiki != '' );
 701         }
 702
 703         /**
 704          * Get the interwiki prefix (or null string)
 705          *
 706          * @return String Interwiki prefix
 707          */
 708         public function getInterwiki() {
 709                 return $this->mInterwiki;
 710         }
 711
 712         /**
 713          * Determine whether the object refers to a page within
 714          * this project and is transcludable.
 715          *
 716          * @return Bool TRUE if this is transcludable
 717          */
 718         public function isTrans() {
 719                 if ( $this->mInterwiki == '' ) {
 720                         return false;
 721                 }
 722
 723                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 724         }
 725
 726         /**
 727          * Returns the DB name of the distant wiki which owns the object.
 728          *
 729          * @return String the DB name
 730          */
 731         public function getTransWikiID() {
 732                 if ( $this->mInterwiki == '' ) {
 733                         return false;
 734                 }
 735
 736                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 737         }
 738
 739         /**
 740          * Get the text form (spaces not underscores) of the main part
 741          *
 742          * @return String Main part of the title
 743          */
 744         public function getText() {
 745                 return $this->mTextform;
 746         }
 747
 748         /**
 749          * Get the URL-encoded form of the main part
 750          *
 751          * @return String Main part of the title, URL-encoded
 752          */
 753         public function getPartialURL() {
 754                 return $this->mUrlform;
 755         }
 756
 757         /**
 758          * Get the main part with underscores
 759          *
 760          * @return String: Main part of the title, with underscores
 761          */
 762         public function getDBkey() {
 763                 return $this->mDbkeyform;
 764         }
 765
 766         /**
 767          * Get the DB key with the initial letter case as specified by the user
 768          *
 769          * @return String DB key
 770          */
 771         function getUserCaseDBKey() {
 772                 return $this->mUserCaseDBKey;
 773         }
 774
 775         /**
 776          * Get the namespace index, i.e. one of the NS_xxxx constants.
 777          *
 778          * @return Integer: Namespace index
 779          */
 780         public function getNamespace() {
 781                 return $this->mNamespace;
 782         }
 783
 784         /**
 785          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 786          *
 787          * @throws MWException
 788          * @return String: Content model id
 789          */
 790         public function getContentModel() {
 791                 if ( !$this->mContentModel ) {
 792                         $linkCache = LinkCache::singleton();
 793                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 794                 }
 795
 796                 if ( !$this->mContentModel ) {
 797                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 798                 }
 799
 800                 if ( !$this->mContentModel ) {
 801                         throw new MWException( 'Failed to determine content model!' );
 802                 }
 803
 804                 return $this->mContentModel;
 805         }
 806
 807         /**
 808          * Convenience method for checking a title's content model name
 809          *
 810          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 811          * @return Boolean true if $this->getContentModel() == $id
 812          */
 813         public function hasContentModel( $id ) {
 814                 return $this->getContentModel() == $id;
 815         }
 816
 817         /**
 818          * Get the namespace text
 819          *
 820          * @return String: Namespace text
 821          */
 822         public function getNsText() {
 823                 global $wgContLang;
 824
 825                 if ( $this->mInterwiki != '' ) {
 826                         // This probably shouldn't even happen. ohh man, oh yuck.
 827                         // But for interwiki transclusion it sometimes does.
 828                         // Shit. Shit shit shit.
 829                         //
 830                         // Use the canonical namespaces if possible to try to
 831                         // resolve a foreign namespace.
 832                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 833                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 834                         }
 835                 }
 836
 837                 if ( $wgContLang->needsGenderDistinction() &&
 838                                 MWNamespace::hasGenderDistinction( $this->mNamespace ) ) {
 839                         $gender = GenderCache::singleton()->getGenderOf( $this->getText(), __METHOD__ );
 840                         return $wgContLang->getGenderNsText( $this->mNamespace, $gender );
 841                 }
 842
 843                 return $wgContLang->getNsText( $this->mNamespace );
 844         }
 845
 846         /**
 847          * Get the namespace text of the subject (rather than talk) page
 848          *
 849          * @return String Namespace text
 850          */
 851         public function getSubjectNsText() {
 852                 global $wgContLang;
 853                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 854         }
 855
 856         /**
 857          * Get the namespace text of the talk page
 858          *
 859          * @return String Namespace text
 860          */
 861         public function getTalkNsText() {
 862                 global $wgContLang;
 863                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
 864         }
 865
 866         /**
 867          * Could this title have a corresponding talk page?
 868          *
 869          * @return Bool TRUE or FALSE
 870          */
 871         public function canTalk() {
 872                 return MWNamespace::canTalk( $this->mNamespace );
 873         }
 874
 875         /**
 876          * Is this in a namespace that allows actual pages?
 877          *
 878          * @return Bool
 879          * @internal note -- uses hardcoded namespace index instead of constants
 880          */
 881         public function canExist() {
 882                 return $this->mNamespace >= NS_MAIN;
 883         }
 884
 885         /**
 886          * Can this title be added to a user's watchlist?
 887          *
 888          * @return Bool TRUE or FALSE
 889          */
 890         public function isWatchable() {
 891                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
 892         }
 893
 894         /**
 895          * Returns true if this is a special page.
 896          *
 897          * @return boolean
 898          */
 899         public function isSpecialPage() {
 900                 return $this->getNamespace() == NS_SPECIAL;
 901         }
 902
 903         /**
 904          * Returns true if this title resolves to the named special page
 905          *
 906          * @param string $name The special page name
 907          * @return boolean
 908          */
 909         public function isSpecial( $name ) {
 910                 if ( $this->isSpecialPage() ) {
 911                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
 912                         if ( $name == $thisName ) {
 913                                 return true;
 914                         }
 915                 }
 916                 return false;
 917         }
 918
 919         /**
 920          * If the Title refers to a special page alias which is not the local default, resolve
 921          * the alias, and localise the name as necessary.  Otherwise, return $this
 922          *
 923          * @return Title
 924          */
 925         public function fixSpecialName() {
 926                 if ( $this->isSpecialPage() ) {
 927                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
 928                         if ( $canonicalName ) {
 929                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
 930                                 if ( $localName != $this->mDbkeyform ) {
 931                                         return Title::makeTitle( NS_SPECIAL, $localName );
 932                                 }
 933                         }
 934                 }
 935                 return $this;
 936         }
 937
 938         /**
 939          * Returns true if the title is inside the specified namespace.
 940          *
 941          * Please make use of this instead of comparing to getNamespace()
 942          * This function is much more resistant to changes we may make
 943          * to namespaces than code that makes direct comparisons.
 944          * @param int $ns The namespace
 945          * @return bool
 946          * @since 1.19
 947          */
 948         public function inNamespace( $ns ) {
 949                 return MWNamespace::equals( $this->getNamespace(), $ns );
 950         }
 951
 952         /**
 953          * Returns true if the title is inside one of the specified namespaces.
 954          *
 955          * @param ...$namespaces The namespaces to check for
 956          * @return bool
 957          * @since 1.19
 958          */
 959         public function inNamespaces( /* ... */ ) {
 960                 $namespaces = func_get_args();
 961                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
 962                         $namespaces = $namespaces[0];
 963                 }
 964
 965                 foreach ( $namespaces as $ns ) {
 966                         if ( $this->inNamespace( $ns ) ) {
 967                                 return true;
 968                         }
 969                 }
 970
 971                 return false;
 972         }
 973
 974         /**
 975          * Returns true if the title has the same subject namespace as the
 976          * namespace specified.
 977          * For example this method will take NS_USER and return true if namespace
 978          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
 979          * as their subject namespace.
 980          *
 981          * This is MUCH simpler than individually testing for equivalence
 982          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
 983          * @since 1.19
 984          * @param $ns int
 985          * @return bool
 986          */
 987         public function hasSubjectNamespace( $ns ) {
 988                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
 989         }
 990
 991         /**
 992          * Is this Title in a namespace which contains content?
 993          * In other words, is this a content page, for the purposes of calculating
 994          * statistics, etc?
 995          *
 996          * @return Boolean
 997          */
 998         public function isContentPage() {
 999                 return MWNamespace::isContent( $this->getNamespace() );
1000         }
1001
1002         /**
1003          * Would anybody with sufficient privileges be able to move this page?
1004          * Some pages just aren't movable.
1005          *
1006          * @return Bool TRUE or FALSE
1007          */
1008         public function isMovable() {
1009                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->getInterwiki() != '' ) {
1010                         // Interwiki title or immovable namespace. Hooks don't get to override here
1011                         return false;
1012                 }
1013
1014                 $result = true;
1015                 wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
1016                 return $result;
1017         }
1018
1019         /**
1020          * Is this the mainpage?
1021          * @note Title::newFromText seems to be sufficiently optimized by the title
1022          * cache that we don't need to over-optimize by doing direct comparisons and
1023          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1024          * ends up reporting something differently than $title->isMainPage();
1025          *
1026          * @since 1.18
1027          * @return Bool
1028          */
1029         public function isMainPage() {
1030                 return $this->equals( Title::newMainPage() );
1031         }
1032
1033         /**
1034          * Is this a subpage?
1035          *
1036          * @return Bool
1037          */
1038         public function isSubpage() {
1039                 return MWNamespace::hasSubpages( $this->mNamespace )
1040                         ? strpos( $this->getText(), '/' ) !== false
1041                         : false;
1042         }
1043
1044         /**
1045          * Is this a conversion table for the LanguageConverter?
1046          *
1047          * @return Bool
1048          */
1049         public function isConversionTable() {
1050                 // @todo ConversionTable should become a separate content model.
1051
1052                 return $this->getNamespace() == NS_MEDIAWIKI &&
1053                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1054         }
1055
1056         /**
1057          * Does that page contain wikitext, or it is JS, CSS or whatever?
1058          *
1059          * @return Bool
1060          */
1061         public function isWikitextPage() {
1062                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1063         }
1064
1065         /**
1066          * Could this page contain custom CSS or JavaScript for the global UI.
1067          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1068          * or CONTENT_MODEL_JAVASCRIPT.
1069          *
1070          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage() for that!
1071          *
1072          * Note that this method should not return true for pages that contain and show "inactive" CSS or JS.
1073          *
1074          * @return Bool
1075          */
1076         public function isCssOrJsPage() {
1077                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1078                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1079                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1080
1081                 #NOTE: this hook is also called in ContentHandler::getDefaultModel. It's called here again to make sure
1082                 #      hook functions can force this method to return true even outside the mediawiki namespace.
1083
1084                 wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ) );
1085
1086                 return $isCssOrJsPage;
1087         }
1088
1089         /**
1090          * Is this a .css or .js subpage of a user page?
1091          * @return Bool
1092          */
1093         public function isCssJsSubpage() {
1094                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1095                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1096                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1097         }
1098
1099         /**
1100          * Trim down a .css or .js subpage title to get the corresponding skin name
1101          *
1102          * @return string containing skin name from .css or .js subpage title
1103          */
1104         public function getSkinFromCssJsSubpage() {
1105                 $subpage = explode( '/', $this->mTextform );
1106                 $subpage = $subpage[count( $subpage ) - 1];
1107                 $lastdot = strrpos( $subpage, '.' );
1108                 if ( $lastdot === false ) {
1109                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1110                 }
1111                 return substr( $subpage, 0, $lastdot );
1112         }
1113
1114         /**
1115          * Is this a .css subpage of a user page?
1116          *
1117          * @return Bool
1118          */
1119         public function isCssSubpage() {
1120                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1121                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1122         }
1123
1124         /**
1125          * Is this a .js subpage of a user page?
1126          *
1127          * @return Bool
1128          */
1129         public function isJsSubpage() {
1130                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1131                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1132         }
1133
1134         /**
1135          * Is this a talk page of some sort?
1136          *
1137          * @return Bool
1138          */
1139         public function isTalkPage() {
1140                 return MWNamespace::isTalk( $this->getNamespace() );
1141         }
1142
1143         /**
1144          * Get a Title object associated with the talk page of this article
1145          *
1146          * @return Title the object for the talk page
1147          */
1148         public function getTalkPage() {
1149                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1150         }
1151
1152         /**
1153          * Get a title object associated with the subject page of this
1154          * talk page
1155          *
1156          * @return Title the object for the subject page
1157          */
1158         public function getSubjectPage() {
1159                 // Is this the same title?
1160                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1161                 if ( $this->getNamespace() == $subjectNS ) {
1162                         return $this;
1163                 }
1164                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1165         }
1166
1167         /**
1168          * Get the default namespace index, for when there is no namespace
1169          *
1170          * @return Int Default namespace index
1171          */
1172         public function getDefaultNamespace() {
1173                 return $this->mDefaultNamespace;
1174         }
1175
1176         /**
1177          * Get title for search index
1178          *
1179          * @return String a stripped-down title string ready for the
1180          *  search index
1181          */
1182         public function getIndexTitle() {
1183                 return Title::indexTitle( $this->mNamespace, $this->mTextform );
1184         }
1185
1186         /**
1187          * Get the Title fragment (i.e.\ the bit after the #) in text form
1188          *
1189          * @return String Title fragment
1190          */
1191         public function getFragment() {
1192                 return $this->mFragment;
1193         }
1194
1195         /**
1196          * Get the fragment in URL form, including the "#" character if there is one
1197          * @return String Fragment in URL form
1198          */
1199         public function getFragmentForURL() {
1200                 if ( $this->mFragment == '' ) {
1201                         return '';
1202                 } else {
1203                         return '#' . Title::escapeFragmentForURL( $this->mFragment );
1204                 }
1205         }
1206
1207         /**
1208          * Set the fragment for this title. Removes the first character from the
1209          * specified fragment before setting, so it assumes you're passing it with
1210          * an initial "#".
1211          *
1212          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1213          * Still in active use privately.
1214          *
1215          * @param string $fragment text
1216          */
1217         public function setFragment( $fragment ) {
1218                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1219         }
1220
1221         /**
1222          * Prefix some arbitrary text with the namespace or interwiki prefix
1223          * of this object
1224          *
1225          * @param string $name the text
1226          * @return String the prefixed text
1227          * @private
1228          */
1229         private function prefix( $name ) {
1230                 $p = '';
1231                 if ( $this->mInterwiki != '' ) {
1232                         $p = $this->mInterwiki . ':';
1233                 }
1234
1235                 if ( 0 != $this->mNamespace ) {
1236                         $p .= $this->getNsText() . ':';
1237                 }
1238                 return $p . $name;
1239         }
1240
1241         /**
1242          * Get the prefixed database key form
1243          *
1244          * @return String the prefixed title, with underscores and
1245          *  any interwiki and namespace prefixes
1246          */
1247         public function getPrefixedDBkey() {
1248                 $s = $this->prefix( $this->mDbkeyform );
1249                 $s = str_replace( ' ', '_', $s );
1250                 return $s;
1251         }
1252
1253         /**
1254          * Get the prefixed title with spaces.
1255          * This is the form usually used for display
1256          *
1257          * @return String the prefixed title, with spaces
1258          */
1259         public function getPrefixedText() {
1260                 // @todo FIXME: Bad usage of empty() ?
1261                 if ( empty( $this->mPrefixedText ) ) {
1262                         $s = $this->prefix( $this->mTextform );
1263                         $s = str_replace( '_', ' ', $s );
1264                         $this->mPrefixedText = $s;
1265                 }
1266                 return $this->mPrefixedText;
1267         }
1268
1269         /**
1270          * Return a string representation of this title
1271          *
1272          * @return String representation of this title
1273          */
1274         public function __toString() {
1275                 return $this->getPrefixedText();
1276         }
1277
1278         /**
1279          * Get the prefixed title with spaces, plus any fragment
1280          * (part beginning with '#')
1281          *
1282          * @return String the prefixed title, with spaces and the fragment, including '#'
1283          */
1284         public function getFullText() {
1285                 $text = $this->getPrefixedText();
1286                 if ( $this->mFragment != '' ) {
1287                         $text .= '#' . $this->mFragment;
1288                 }
1289                 return $text;
1290         }
1291
1292         /**
1293          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1294          *
1295          * @par Example:
1296          * @code
1297          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1298          * # returns: 'Foo'
1299          * @endcode
1300          *
1301          * @return String Root name
1302          * @since 1.20
1303          */
1304         public function getRootText() {
1305                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1306                         return $this->getText();
1307                 }
1308
1309                 return strtok( $this->getText(), '/' );
1310         }
1311
1312         /**
1313          * Get the root page name title, i.e. the leftmost part before any slashes
1314          *
1315          * @par Example:
1316          * @code
1317          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1318          * # returns: Title{User:Foo}
1319          * @endcode
1320          *
1321          * @return Title Root title
1322          * @since 1.20
1323          */
1324         public function getRootTitle() {
1325                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1326         }
1327
1328         /**
1329          * Get the base page name without a namespace, i.e. the part before the subpage name
1330          *
1331          * @par Example:
1332          * @code
1333          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1334          * # returns: 'Foo/Bar'
1335          * @endcode
1336          *
1337          * @return String Base name
1338          */
1339         public function getBaseText() {
1340                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1341                         return $this->getText();
1342                 }
1343
1344                 $parts = explode( '/', $this->getText() );
1345                 # Don't discard the real title if there's no subpage involved
1346                 if ( count( $parts ) > 1 ) {
1347                         unset( $parts[count( $parts ) - 1] );
1348                 }
1349                 return implode( '/', $parts );
1350         }
1351
1352         /**
1353          * Get the base page name title, i.e. the part before the subpage name
1354          *
1355          * @par Example:
1356          * @code
1357          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1358          * # returns: Title{User:Foo/Bar}
1359          * @endcode
1360          *
1361          * @return Title Base title
1362          * @since 1.20
1363          */
1364         public function getBaseTitle() {
1365                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1366         }
1367
1368         /**
1369          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1370          *
1371          * @par Example:
1372          * @code
1373          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1374          * # returns: "Baz"
1375          * @endcode
1376          *
1377          * @return String Subpage name
1378          */
1379         public function getSubpageText() {
1380                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1381                         return $this->mTextform;
1382                 }
1383                 $parts = explode( '/', $this->mTextform );
1384                 return $parts[count( $parts ) - 1];
1385         }
1386
1387         /**
1388          * Get the title for a subpage of the current page
1389          *
1390          * @par Example:
1391          * @code
1392          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1393          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1394          * @endcode
1395          *
1396          * @param string $text The subpage name to add to the title
1397          * @return Title Subpage title
1398          * @since 1.20
1399          */
1400         public function getSubpage( $text ) {
1401                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1402         }
1403
1404         /**
1405          * Get the HTML-escaped displayable text form.
1406          * Used for the title field in <a> tags.
1407          *
1408          * @return String the text, including any prefixes
1409          * @deprecated since 1.19
1410          */
1411         public function getEscapedText() {
1412                 wfDeprecated( __METHOD__, '1.19' );
1413                 return htmlspecialchars( $this->getPrefixedText() );
1414         }
1415
1416         /**
1417          * Get a URL-encoded form of the subpage text
1418          *
1419          * @return String URL-encoded subpage name
1420          */
1421         public function getSubpageUrlForm() {
1422                 $text = $this->getSubpageText();
1423                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1424                 return $text;
1425         }
1426
1427         /**
1428          * Get a URL-encoded title (not an actual URL) including interwiki
1429          *
1430          * @return String the URL-encoded form
1431          */
1432         public function getPrefixedURL() {
1433                 $s = $this->prefix( $this->mDbkeyform );
1434                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1435                 return $s;
1436         }
1437
1438         /**
1439          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1440          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1441          * second argument named variant. This was deprecated in favor
1442          * of passing an array of option with a "variant" key
1443          * Once $query2 is removed for good, this helper can be dropped
1444          * and the wfArrayToCgi moved to getLocalURL();
1445          *
1446          * @since 1.19 (r105919)
1447          * @param $query
1448          * @param $query2 bool
1449          * @return String
1450          */
1451         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1452                 if ( $query2 !== false ) {
1453                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1454                                 "method called with a second parameter is deprecated. Add your " .
1455                                 "parameter to an array passed as the first parameter.", "1.19" );
1456                 }
1457                 if ( is_array( $query ) ) {
1458                         $query = wfArrayToCgi( $query );
1459                 }
1460                 if ( $query2 ) {
1461                         if ( is_string( $query2 ) ) {
1462                                 // $query2 is a string, we will consider this to be
1463                                 // a deprecated $variant argument and add it to the query
1464                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1465                         } else {
1466                                 $query2 = wfArrayToCgi( $query2 );
1467                         }
1468                         // If we have $query content add a & to it first
1469                         if ( $query ) {
1470                                 $query .= '&';
1471                         }
1472                         // Now append the queries together
1473                         $query .= $query2;
1474                 }
1475                 return $query;
1476         }
1477
1478         /**
1479          * Get a real URL referring to this title, with interwiki link and
1480          * fragment
1481          *
1482          * See getLocalURL for the arguments.
1483          *
1484          * @see self::getLocalURL
1485          * @see wfExpandUrl
1486          * @param $query
1487          * @param $query2 bool
1488          * @param $proto Protocol type to use in URL
1489          * @return String the URL
1490          */
1491         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1492                 $query = self::fixUrlQueryArgs( $query, $query2 );
1493
1494                 # Hand off all the decisions on urls to getLocalURL
1495                 $url = $this->getLocalURL( $query );
1496
1497                 # Expand the url to make it a full url. Note that getLocalURL has the
1498                 # potential to output full urls for a variety of reasons, so we use
1499                 # wfExpandUrl instead of simply prepending $wgServer
1500                 $url = wfExpandUrl( $url, $proto );
1501
1502                 # Finally, add the fragment.
1503                 $url .= $this->getFragmentForURL();
1504
1505                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1506                 return $url;
1507         }
1508
1509         /**
1510          * Get a URL with no fragment or server name.  If this page is generated
1511          * with action=render, $wgServer is prepended.
1512          *
1513          * @param string|array $query an optional query string,
1514          *   not used for interwiki links. Can be specified as an associative array as well,
1515          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1516          *   Some query patterns will trigger various shorturl path replacements.
1517          * @param $query2 Mixed: An optional secondary query array. This one MUST
1518          *   be an array. If a string is passed it will be interpreted as a deprecated
1519          *   variant argument and urlencoded into a variant= argument.
1520          *   This second query argument will be added to the $query
1521          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1522          *   pair in the first parameter array instead.
1523          *
1524          * @return String the URL
1525          */
1526         public function getLocalURL( $query = '', $query2 = false ) {
1527                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1528
1529                 $query = self::fixUrlQueryArgs( $query, $query2 );
1530
1531                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1532                 if ( $interwiki ) {
1533                         $namespace = $this->getNsText();
1534                         if ( $namespace != '' ) {
1535                                 # Can this actually happen? Interwikis shouldn't be parsed.
1536                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1537                                 $namespace .= ':';
1538                         }
1539                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1540                         $url = wfAppendQuery( $url, $query );
1541                 } else {
1542                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1543                         if ( $query == '' ) {
1544                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1545                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1546                         } else {
1547                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1548                                 $url = false;
1549                                 $matches = array();
1550
1551                                 if ( !empty( $wgActionPaths ) &&
1552                                         preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches ) )
1553                                 {
1554                                         $action = urldecode( $matches[2] );
1555                                         if ( isset( $wgActionPaths[$action] ) ) {
1556                                                 $query = $matches[1];
1557                                                 if ( isset( $matches[4] ) ) {
1558                                                         $query .= $matches[4];
1559                                                 }
1560                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1561                                                 if ( $query != '' ) {
1562                                                         $url = wfAppendQuery( $url, $query );
1563                                                 }
1564                                         }
1565                                 }
1566
1567                                 if ( $url === false &&
1568                                         $wgVariantArticlePath &&
1569                                         $wgContLang->getCode() === $this->getPageLanguage()->getCode() &&
1570                                         $this->getPageLanguage()->hasVariants() &&
1571                                         preg_match( '/^variant=([^&]*)$/', $query, $matches ) )
1572                                 {
1573                                         $variant = urldecode( $matches[1] );
1574                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1575                                                 // Only do the variant replacement if the given variant is a valid
1576                                                 // variant for the page's language.
1577                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1578                                                 $url = str_replace( '$1', $dbkey, $url );
1579                                         }
1580                                 }
1581
1582                                 if ( $url === false ) {
1583                                         if ( $query == '-' ) {
1584                                                 $query = '';
1585                                         }
1586                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1587                                 }
1588                         }
1589
1590                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1591
1592                         // @todo FIXME: This causes breakage in various places when we
1593                         // actually expected a local URL and end up with dupe prefixes.
1594                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1595                                 $url = $wgServer . $url;
1596                         }
1597                 }
1598                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1599                 return $url;
1600         }
1601
1602         /**
1603          * Get a URL that's the simplest URL that will be valid to link, locally,
1604          * to the current Title.  It includes the fragment, but does not include
1605          * the server unless action=render is used (or the link is external).  If
1606          * there's a fragment but the prefixed text is empty, we just return a link
1607          * to the fragment.
1608          *
1609          * The result obviously should not be URL-escaped, but does need to be
1610          * HTML-escaped if it's being output in HTML.
1611          *
1612          * See getLocalURL for the arguments.
1613          *
1614          * @param $query
1615          * @param $query2 bool
1616          * @param $proto Protocol to use; setting this will cause a full URL to be used
1617          * @see self::getLocalURL
1618          * @return String the URL
1619          */
1620         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1621                 wfProfileIn( __METHOD__ );
1622                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1623                         $ret = $this->getFullURL( $query, $query2, $proto );
1624                 } elseif ( $this->getPrefixedText() === '' && $this->getFragment() !== '' ) {
1625                         $ret = $this->getFragmentForURL();
1626                 } else {
1627                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1628                 }
1629                 wfProfileOut( __METHOD__ );
1630                 return $ret;
1631         }
1632
1633         /**
1634          * Get an HTML-escaped version of the URL form, suitable for
1635          * using in a link, without a server name or fragment
1636          *
1637          * See getLocalURL for the arguments.
1638          *
1639          * @see self::getLocalURL
1640          * @param $query string
1641          * @param $query2 bool|string
1642          * @return String the URL
1643          * @deprecated since 1.19
1644          */
1645         public function escapeLocalURL( $query = '', $query2 = false ) {
1646                 wfDeprecated( __METHOD__, '1.19' );
1647                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1648         }
1649
1650         /**
1651          * Get an HTML-escaped version of the URL form, suitable for
1652          * using in a link, including the server name and fragment
1653          *
1654          * See getLocalURL for the arguments.
1655          *
1656          * @see self::getLocalURL
1657          * @return String the URL
1658          * @deprecated since 1.19
1659          */
1660         public function escapeFullURL( $query = '', $query2 = false ) {
1661                 wfDeprecated( __METHOD__, '1.19' );
1662                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1663         }
1664
1665         /**
1666          * Get the URL form for an internal link.
1667          * - Used in various Squid-related code, in case we have a different
1668          * internal hostname for the server from the exposed one.
1669          *
1670          * This uses $wgInternalServer to qualify the path, or $wgServer
1671          * if $wgInternalServer is not set. If the server variable used is
1672          * protocol-relative, the URL will be expanded to http://
1673          *
1674          * See getLocalURL for the arguments.
1675          *
1676          * @see self::getLocalURL
1677          * @return String the URL
1678          */
1679         public function getInternalURL( $query = '', $query2 = false ) {
1680                 global $wgInternalServer, $wgServer;
1681                 $query = self::fixUrlQueryArgs( $query, $query2 );
1682                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1683                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1684                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1685                 return $url;
1686         }
1687
1688         /**
1689          * Get the URL for a canonical link, for use in things like IRC and
1690          * e-mail notifications. Uses $wgCanonicalServer and the
1691          * GetCanonicalURL hook.
1692          *
1693          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1694          *
1695          * See getLocalURL for the arguments.
1696          *
1697          * @see self::getLocalURL
1698          * @return string The URL
1699          * @since 1.18
1700          */
1701         public function getCanonicalURL( $query = '', $query2 = false ) {
1702                 $query = self::fixUrlQueryArgs( $query, $query2 );
1703                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1704                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1705                 return $url;
1706         }
1707
1708         /**
1709          * HTML-escaped version of getCanonicalURL()
1710          *
1711          * See getLocalURL for the arguments.
1712          *
1713          * @see self::getLocalURL
1714          * @since 1.18
1715          * @return string
1716          * @deprecated since 1.19
1717          */
1718         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1719                 wfDeprecated( __METHOD__, '1.19' );
1720                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1721         }
1722
1723         /**
1724          * Get the edit URL for this Title
1725          *
1726          * @return String the URL, or a null string if this is an
1727          *  interwiki link
1728          */
1729         public function getEditURL() {
1730                 if ( $this->mInterwiki != '' ) {
1731                         return '';
1732                 }
1733                 $s = $this->getLocalURL( 'action=edit' );
1734
1735                 return $s;
1736         }
1737
1738         /**
1739          * Is $wgUser watching this page?
1740          *
1741          * @deprecated in 1.20; use User::isWatched() instead.
1742          * @return Bool
1743          */
1744         public function userIsWatching() {
1745                 global $wgUser;
1746
1747                 if ( is_null( $this->mWatched ) ) {
1748                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1749                                 $this->mWatched = false;
1750                         } else {
1751                                 $this->mWatched = $wgUser->isWatched( $this );
1752                         }
1753                 }
1754                 return $this->mWatched;
1755         }
1756
1757         /**
1758          * Can $wgUser read this page?
1759          *
1760          * @deprecated in 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1761          * @return Bool
1762          * @todo fold these checks into userCan()
1763          */
1764         public function userCanRead() {
1765                 wfDeprecated( __METHOD__, '1.19' );
1766                 return $this->userCan( 'read' );
1767         }
1768
1769         /**
1770          * Can $user perform $action on this page?
1771          * This skips potentially expensive cascading permission checks
1772          * as well as avoids expensive error formatting
1773          *
1774          * Suitable for use for nonessential UI controls in common cases, but
1775          * _not_ for functional access control.
1776          *
1777          * May provide false positives, but should never provide a false negative.
1778          *
1779          * @param string $action action that permission needs to be checked for
1780          * @param $user User to check (since 1.19); $wgUser will be used if not
1781          *              provided.
1782          * @return Bool
1783          */
1784         public function quickUserCan( $action, $user = null ) {
1785                 return $this->userCan( $action, $user, false );
1786         }
1787
1788         /**
1789          * Can $user perform $action on this page?
1790          *
1791          * @param string $action action that permission needs to be checked for
1792          * @param $user User to check (since 1.19); $wgUser will be used if not
1793          *   provided.
1794          * @param bool $doExpensiveQueries Set this to false to avoid doing
1795          *   unnecessary queries.
1796          * @return Bool
1797          */
1798         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1799                 if ( !$user instanceof User ) {
1800                         global $wgUser;
1801                         $user = $wgUser;
1802                 }
1803                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries, true ) );
1804         }
1805
1806         /**
1807          * Can $user perform $action on this page?
1808          *
1809          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1810          *
1811          * @param string $action action that permission needs to be checked for
1812          * @param $user User to check
1813          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1814          *   queries by skipping checks for cascading protections and user blocks.
1815          * @param array $ignoreErrors of Strings Set this to a list of message keys
1816          *   whose corresponding errors may be ignored.
1817          * @return Array of arguments to wfMessage to explain permissions problems.
1818          */
1819         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
1820                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1821
1822                 // Remove the errors being ignored.
1823                 foreach ( $errors as $index => $error ) {
1824                         $error_key = is_array( $error ) ? $error[0] : $error;
1825
1826                         if ( in_array( $error_key, $ignoreErrors ) ) {
1827                                 unset( $errors[$index] );
1828                         }
1829                 }
1830
1831                 return $errors;
1832         }
1833
1834         /**
1835          * Permissions checks that fail most often, and which are easiest to test.
1836          *
1837          * @param string $action the action to check
1838          * @param $user User user to check
1839          * @param array $errors list of current errors
1840          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1841          * @param $short Boolean short circuit on first error
1842          *
1843          * @return Array list of errors
1844          */
1845         private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1846                 if ( !wfRunHooks( 'TitleQuickPermissions', array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) ) ) {
1847                         return $errors;
1848                 }
1849
1850                 if ( $action == 'create' ) {
1851                         if (
1852                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1853                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1854                         ) {
1855                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1856                         }
1857                 } elseif ( $action == 'move' ) {
1858                         if ( !$user->isAllowed( 'move-rootuserpages' )
1859                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1860                                 // Show user page-specific message only if the user can move other pages
1861                                 $errors[] = array( 'cant-move-user-page' );
1862                         }
1863
1864                         // Check if user is allowed to move files if it's a file
1865                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1866                                 $errors[] = array( 'movenotallowedfile' );
1867                         }
1868
1869                         if ( !$user->isAllowed( 'move' ) ) {
1870                                 // User can't move anything
1871                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1872                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1873                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1874                                         // custom message if logged-in users without any special rights can move
1875                                         $errors[] = array( 'movenologintext' );
1876                                 } else {
1877                                         $errors[] = array( 'movenotallowed' );
1878                                 }
1879                         }
1880                 } elseif ( $action == 'move-target' ) {
1881                         if ( !$user->isAllowed( 'move' ) ) {
1882                                 // User can't move anything
1883                                 $errors[] = array( 'movenotallowed' );
1884                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1885                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1886                                 // Show user page-specific message only if the user can move other pages
1887                                 $errors[] = array( 'cant-move-to-user-page' );
1888                         }
1889                 } elseif ( !$user->isAllowed( $action ) ) {
1890                         $errors[] = $this->missingPermissionError( $action, $short );
1891                 }
1892
1893                 return $errors;
1894         }
1895
1896         /**
1897          * Add the resulting error code to the errors array
1898          *
1899          * @param array $errors list of current errors
1900          * @param $result Mixed result of errors
1901          *
1902          * @return Array list of errors
1903          */
1904         private function resultToError( $errors, $result ) {
1905                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1906                         // A single array representing an error
1907                         $errors[] = $result;
1908                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
1909                         // A nested array representing multiple errors
1910                         $errors = array_merge( $errors, $result );
1911                 } elseif ( $result !== '' && is_string( $result ) ) {
1912                         // A string representing a message-id
1913                         $errors[] = array( $result );
1914                 } elseif ( $result === false ) {
1915                         // a generic "We don't want them to do that"
1916                         $errors[] = array( 'badaccess-group0' );
1917                 }
1918                 return $errors;
1919         }
1920
1921         /**
1922          * Check various permission hooks
1923          *
1924          * @param string $action the action to check
1925          * @param $user User user to check
1926          * @param array $errors list of current errors
1927          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1928          * @param $short Boolean short circuit on first error
1929          *
1930          * @return Array list of errors
1931          */
1932         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
1933                 // Use getUserPermissionsErrors instead
1934                 $result = '';
1935                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
1936                         return $result ? array() : array( array( 'badaccess-group0' ) );
1937                 }
1938                 // Check getUserPermissionsErrors hook
1939                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
1940                         $errors = $this->resultToError( $errors, $result );
1941                 }
1942                 // Check getUserPermissionsErrorsExpensive hook
1943                 if (
1944                         $doExpensiveQueries
1945                         && !( $short && count( $errors ) > 0 )
1946                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
1947                 ) {
1948                         $errors = $this->resultToError( $errors, $result );
1949                 }
1950
1951                 return $errors;
1952         }
1953
1954         /**
1955          * Check permissions on special pages & namespaces
1956          *
1957          * @param string $action the action to check
1958          * @param $user User user to check
1959          * @param array $errors list of current errors
1960          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1961          * @param $short Boolean short circuit on first error
1962          *
1963          * @return Array list of errors
1964          */
1965         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1966                 # Only 'createaccount' can be performed on special pages,
1967                 # which don't actually exist in the DB.
1968                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
1969                         $errors[] = array( 'ns-specialprotected' );
1970                 }
1971
1972                 # Check $wgNamespaceProtection for restricted namespaces
1973                 if ( $this->isNamespaceProtected( $user ) ) {
1974                         $ns = $this->mNamespace == NS_MAIN ?
1975                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
1976                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
1977                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
1978                 }
1979
1980                 return $errors;
1981         }
1982
1983         /**
1984          * Check CSS/JS sub-page permissions
1985          *
1986          * @param string $action the action to check
1987          * @param $user User user to check
1988          * @param array $errors list of current errors
1989          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1990          * @param $short Boolean short circuit on first error
1991          *
1992          * @return Array list of errors
1993          */
1994         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1995                 # Protect css/js subpages of user pages
1996                 # XXX: this might be better using restrictions
1997                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
1998                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
1999                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2000                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2001                                         $errors[] = array( 'mycustomcssprotected' );
2002                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2003                                         $errors[] = array( 'mycustomjsprotected' );
2004                                 }
2005                         } else {
2006                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2007                                         $errors[] = array( 'customcssprotected' );
2008                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2009                                         $errors[] = array( 'customjsprotected' );
2010                                 }
2011                         }
2012                 }
2013
2014                 return $errors;
2015         }
2016
2017         /**
2018          * Check against page_restrictions table requirements on this
2019          * page. The user must possess all required rights for this
2020          * action.
2021          *
2022          * @param string $action the action to check
2023          * @param $user User user to check
2024          * @param array $errors list of current errors
2025          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2026          * @param $short Boolean short circuit on first error
2027          *
2028          * @return Array list of errors
2029          */
2030         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2031                 foreach ( $this->getRestrictions( $action ) as $right ) {
2032                         // Backwards compatibility, rewrite sysop -> editprotected
2033                         if ( $right == 'sysop' ) {
2034                                 $right = 'editprotected';
2035                         }
2036                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2037                         if ( $right == 'autoconfirmed' ) {
2038                                 $right = 'editsemiprotected';
2039                         }
2040                         if ( $right == '' ) {
2041                                 continue;
2042                         }
2043                         if ( !$user->isAllowed( $right ) ) {
2044                                 $errors[] = array( 'protectedpagetext', $right );
2045                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2046                                 $errors[] = array( 'protectedpagetext', 'protect' );
2047                         }
2048                 }
2049
2050                 return $errors;
2051         }
2052
2053         /**
2054          * Check restrictions on cascading pages.
2055          *
2056          * @param string $action the action to check
2057          * @param $user User to check
2058          * @param array $errors list of current errors
2059          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2060          * @param $short Boolean short circuit on first error
2061          *
2062          * @return Array list of errors
2063          */
2064         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2065                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2066                         # We /could/ use the protection level on the source page, but it's
2067                         # fairly ugly as we have to establish a precedence hierarchy for pages
2068                         # included by multiple cascade-protected pages. So just restrict
2069                         # it to people with 'protect' permission, as they could remove the
2070                         # protection anyway.
2071                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2072                         # Cascading protection depends on more than this page...
2073                         # Several cascading protected pages may include this page...
2074                         # Check each cascading level
2075                         # This is only for protection restrictions, not for all actions
2076                         if ( isset( $restrictions[$action] ) ) {
2077                                 foreach ( $restrictions[$action] as $right ) {
2078                                         // Backwards compatibility, rewrite sysop -> editprotected
2079                                         if ( $right == 'sysop' ) {
2080                                                 $right = 'editprotected';
2081                                         }
2082                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2083                                         if ( $right == 'autoconfirmed' ) {
2084                                                 $right = 'editsemiprotected';
2085                                         }
2086                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2087                                                 $pages = '';
2088                                                 foreach ( $cascadingSources as $page ) {
2089                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2090                                                 }
2091                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2092                                         }
2093                                 }
2094                         }
2095                 }
2096
2097                 return $errors;
2098         }
2099
2100         /**
2101          * Check action permissions not already checked in checkQuickPermissions
2102          *
2103          * @param string $action the action to check
2104          * @param $user User to check
2105          * @param array $errors list of current errors
2106          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2107          * @param $short Boolean short circuit on first error
2108          *
2109          * @return Array list of errors
2110          */
2111         private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2112                 global $wgDeleteRevisionsLimit, $wgLang;
2113
2114                 if ( $action == 'protect' ) {
2115                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $doExpensiveQueries, true ) ) ) {
2116                                 // If they can't edit, they shouldn't protect.
2117                                 $errors[] = array( 'protect-cantedit' );
2118                         }
2119                 } elseif ( $action == 'create' ) {
2120                         $title_protection = $this->getTitleProtection();
2121                         if ( $title_protection ) {
2122                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2123                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2124                                 }
2125                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2126                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2127                                 }
2128                                 if ( $title_protection['pt_create_perm'] == '' ||
2129                                         !$user->isAllowed( $title_protection['pt_create_perm'] ) )
2130                                 {
2131                                         $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
2132                                 }
2133                         }
2134                 } elseif ( $action == 'move' ) {
2135                         // Check for immobile pages
2136                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2137                                 // Specific message for this case
2138                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2139                         } elseif ( !$this->isMovable() ) {
2140                                 // Less specific message for rarer cases
2141                                 $errors[] = array( 'immobile-source-page' );
2142                         }
2143                 } elseif ( $action == 'move-target' ) {
2144                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2145                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2146                         } elseif ( !$this->isMovable() ) {
2147                                 $errors[] = array( 'immobile-target-page' );
2148                         }
2149                 } elseif ( $action == 'delete' ) {
2150                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2151                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion() )
2152                         {
2153                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2154                         }
2155                 }
2156                 return $errors;
2157         }
2158
2159         /**
2160          * Check that the user isn't blocked from editing.
2161          *
2162          * @param string $action the action to check
2163          * @param $user User to check
2164          * @param array $errors list of current errors
2165          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2166          * @param $short Boolean short circuit on first error
2167          *
2168          * @return Array list of errors
2169          */
2170         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2171                 // Account creation blocks handled at userlogin.
2172                 // Unblocking handled in SpecialUnblock
2173                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2174                         return $errors;
2175                 }
2176
2177                 global $wgEmailConfirmToEdit;
2178
2179                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2180                         $errors[] = array( 'confirmedittext' );
2181                 }
2182
2183                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2184                         // Don't block the user from editing their own talk page unless they've been
2185                         // explicitly blocked from that too.
2186                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2187                         // @todo FIXME: Pass the relevant context into this function.
2188                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2189                 }
2190
2191                 return $errors;
2192         }
2193
2194         /**
2195          * Check that the user is allowed to read this page.
2196          *
2197          * @param string $action the action to check
2198          * @param $user User to check
2199          * @param array $errors list of current errors
2200          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2201          * @param $short Boolean short circuit on first error
2202          *
2203          * @return Array list of errors
2204          */
2205         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2206                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2207
2208                 $whitelisted = false;
2209                 if ( User::isEveryoneAllowed( 'read' ) ) {
2210                         # Shortcut for public wikis, allows skipping quite a bit of code
2211                         $whitelisted = true;
2212                 } elseif ( $user->isAllowed( 'read' ) ) {
2213                         # If the user is allowed to read pages, he is allowed to read all pages
2214                         $whitelisted = true;
2215                 } elseif ( $this->isSpecial( 'Userlogin' )
2216                         || $this->isSpecial( 'ChangePassword' )
2217                         || $this->isSpecial( 'PasswordReset' )
2218                 ) {
2219                         # Always grant access to the login page.
2220                         # Even anons need to be able to log in.
2221                         $whitelisted = true;
2222                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2223                         # Time to check the whitelist
2224                         # Only do these checks is there's something to check against
2225                         $name = $this->getPrefixedText();
2226                         $dbName = $this->getPrefixedDBkey();
2227
2228                         // Check for explicit whitelisting with and without underscores
2229                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2230                                 $whitelisted = true;
2231                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2232                                 # Old settings might have the title prefixed with
2233                                 # a colon for main-namespace pages
2234                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2235                                         $whitelisted = true;
2236                                 }
2237                         } elseif ( $this->isSpecialPage() ) {
2238                                 # If it's a special page, ditch the subpage bit and check again
2239                                 $name = $this->getDBkey();
2240                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2241                                 if ( $name ) {
2242                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2243                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2244                                                 $whitelisted = true;
2245                                         }
2246                                 }
2247                         }
2248                 }
2249
2250                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2251                         $name = $this->getPrefixedText();
2252                         // Check for regex whitelisting
2253                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2254                                 if ( preg_match( $listItem, $name ) ) {
2255                                         $whitelisted = true;
2256                                         break;
2257                                 }
2258                         }
2259                 }
2260
2261                 if ( !$whitelisted ) {
2262                         # If the title is not whitelisted, give extensions a chance to do so...
2263                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2264                         if ( !$whitelisted ) {
2265                                 $errors[] = $this->missingPermissionError( $action, $short );
2266                         }
2267                 }
2268
2269                 return $errors;
2270         }
2271
2272         /**
2273          * Get a description array when the user doesn't have the right to perform
2274          * $action (i.e. when User::isAllowed() returns false)
2275          *
2276          * @param string $action the action to check
2277          * @param $short Boolean short circuit on first error
2278          * @return Array list of errors
2279          */
2280         private function missingPermissionError( $action, $short ) {
2281                 // We avoid expensive display logic for quickUserCan's and such
2282                 if ( $short ) {
2283                         return array( 'badaccess-group0' );
2284                 }
2285
2286                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2287                         User::getGroupsWithPermission( $action ) );
2288
2289                 if ( count( $groups ) ) {
2290                         global $wgLang;
2291                         return array(
2292                                 'badaccess-groups',
2293                                 $wgLang->commaList( $groups ),
2294                                 count( $groups )
2295                         );
2296                 } else {
2297                         return array( 'badaccess-group0' );
2298                 }
2299         }
2300
2301         /**
2302          * Can $user perform $action on this page? This is an internal function,
2303          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2304          * checks on wfReadOnly() and blocks)
2305          *
2306          * @param string $action action that permission needs to be checked for
2307          * @param $user User to check
2308          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2309          * @param bool $short Set this to true to stop after the first permission error.
2310          * @return Array of arrays of the arguments to wfMessage to explain permissions problems.
2311          */
2312         protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
2313                 wfProfileIn( __METHOD__ );
2314
2315                 # Read has special handling
2316                 if ( $action == 'read' ) {
2317                         $checks = array(
2318                                 'checkPermissionHooks',
2319                                 'checkReadPermissions',
2320                         );
2321                 } else {
2322                         $checks = array(
2323                                 'checkQuickPermissions',
2324                                 'checkPermissionHooks',
2325                                 'checkSpecialsAndNSPermissions',
2326                                 'checkCSSandJSPermissions',
2327                                 'checkPageRestrictions',
2328                                 'checkCascadingSourcesRestrictions',
2329                                 'checkActionPermissions',
2330                                 'checkUserBlock'
2331                         );
2332                 }
2333
2334                 $errors = array();
2335                 while ( count( $checks ) > 0 &&
2336                                 !( $short && count( $errors ) > 0 ) ) {
2337                         $method = array_shift( $checks );
2338                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2339                 }
2340
2341                 wfProfileOut( __METHOD__ );
2342                 return $errors;
2343         }
2344
2345         /**
2346          * Get a filtered list of all restriction types supported by this wiki.
2347          * @param bool $exists True to get all restriction types that apply to
2348          * titles that do exist, False for all restriction types that apply to
2349          * titles that do not exist
2350          * @return array
2351          */
2352         public static function getFilteredRestrictionTypes( $exists = true ) {
2353                 global $wgRestrictionTypes;
2354                 $types = $wgRestrictionTypes;
2355                 if ( $exists ) {
2356                         # Remove the create restriction for existing titles
2357                         $types = array_diff( $types, array( 'create' ) );
2358                 } else {
2359                         # Only the create and upload restrictions apply to non-existing titles
2360                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2361                 }
2362                 return $types;
2363         }
2364
2365         /**
2366          * Returns restriction types for the current Title
2367          *
2368          * @return array applicable restriction types
2369          */
2370         public function getRestrictionTypes() {
2371                 if ( $this->isSpecialPage() ) {
2372                         return array();
2373                 }
2374
2375                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2376
2377                 if ( $this->getNamespace() != NS_FILE ) {
2378                         # Remove the upload restriction for non-file titles
2379                         $types = array_diff( $types, array( 'upload' ) );
2380                 }
2381
2382                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2383
2384                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2385                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2386
2387                 return $types;
2388         }
2389
2390         /**
2391          * Is this title subject to title protection?
2392          * Title protection is the one applied against creation of such title.
2393          *
2394          * @return Mixed An associative array representing any existent title
2395          *   protection, or false if there's none.
2396          */
2397         private function getTitleProtection() {
2398                 // Can't protect pages in special namespaces
2399                 if ( $this->getNamespace() < 0 ) {
2400                         return false;
2401                 }
2402
2403                 // Can't protect pages that exist.
2404                 if ( $this->exists() ) {
2405                         return false;
2406                 }
2407
2408                 if ( !isset( $this->mTitleProtection ) ) {
2409                         $dbr = wfGetDB( DB_SLAVE );
2410                         $res = $dbr->select(
2411                                 'protected_titles',
2412                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2413                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2414                                 __METHOD__
2415                         );
2416
2417                         // fetchRow returns false if there are no rows.
2418                         $this->mTitleProtection = $dbr->fetchRow( $res );
2419                 }
2420                 return $this->mTitleProtection;
2421         }
2422
2423         /**
2424          * Update the title protection status
2425          *
2426          * @deprecated in 1.19; use WikiPage::doUpdateRestrictions() instead.
2427          * @param $create_perm String Permission required for creation
2428          * @param string $reason Reason for protection
2429          * @param string $expiry Expiry timestamp
2430          * @return boolean true
2431          */
2432         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2433                 wfDeprecated( __METHOD__, '1.19' );
2434
2435                 global $wgUser;
2436
2437                 $limit = array( 'create' => $create_perm );
2438                 $expiry = array( 'create' => $expiry );
2439
2440                 $page = WikiPage::factory( $this );
2441                 $cascade = false;
2442                 $status = $page->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $wgUser );
2443
2444                 return $status->isOK();
2445         }
2446
2447         /**
2448          * Remove any title protection due to page existing
2449          */
2450         public function deleteTitleProtection() {
2451                 $dbw = wfGetDB( DB_MASTER );
2452
2453                 $dbw->delete(
2454                         'protected_titles',
2455                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2456                         __METHOD__
2457                 );
2458                 $this->mTitleProtection = false;
2459         }
2460
2461         /**
2462          * Is this page "semi-protected" - the *only* protection levels are listed
2463          * in $wgSemiprotectedRestrictionLevels?
2464          *
2465          * @param string $action Action to check (default: edit)
2466          * @return Bool
2467          */
2468         public function isSemiProtected( $action = 'edit' ) {
2469                 global $wgSemiprotectedRestrictionLevels;
2470
2471                 $restrictions = $this->getRestrictions( $action );
2472                 $semi = $wgSemiprotectedRestrictionLevels;
2473                 if ( !$restrictions || !$semi ) {
2474                         // Not protected, or all protection is full protection
2475                         return false;
2476                 }
2477
2478                 // Remap autoconfirmed to editsemiprotected for BC
2479                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2480                         $semi[$key] = 'editsemiprotected';
2481                 }
2482                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2483                         $restrictions[$key] = 'editsemiprotected';
2484                 }
2485
2486                 return !array_diff( $restrictions, $semi );
2487         }
2488
2489         /**
2490          * Does the title correspond to a protected article?
2491          *
2492          * @param string $action the action the page is protected from,
2493          * by default checks all actions.
2494          * @return Bool
2495          */
2496         public function isProtected( $action = '' ) {
2497                 global $wgRestrictionLevels;
2498
2499                 $restrictionTypes = $this->getRestrictionTypes();
2500
2501                 # Special pages have inherent protection
2502                 if ( $this->isSpecialPage() ) {
2503                         return true;
2504                 }
2505
2506                 # Check regular protection levels
2507                 foreach ( $restrictionTypes as $type ) {
2508                         if ( $action == $type || $action == '' ) {
2509                                 $r = $this->getRestrictions( $type );
2510                                 foreach ( $wgRestrictionLevels as $level ) {
2511                                         if ( in_array( $level, $r ) && $level != '' ) {
2512                                                 return true;
2513                                         }
2514                                 }
2515                         }
2516                 }
2517
2518                 return false;
2519         }
2520
2521         /**
2522          * Determines if $user is unable to edit this page because it has been protected
2523          * by $wgNamespaceProtection.
2524          *
2525          * @param $user User object to check permissions
2526          * @return Bool
2527          */
2528         public function isNamespaceProtected( User $user ) {
2529                 global $wgNamespaceProtection;
2530
2531                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2532                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2533                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2534                                         return true;
2535                                 }
2536                         }
2537                 }
2538                 return false;
2539         }
2540
2541         /**
2542          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2543          *
2544          * @return Bool If the page is subject to cascading restrictions.
2545          */
2546         public function isCascadeProtected() {
2547                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2548                 return ( $sources > 0 );
2549         }
2550
2551         /**
2552          * Cascading protection: Get the source of any cascading restrictions on this page.
2553          *
2554          * @param bool $getPages Whether or not to retrieve the actual pages
2555          *        that the restrictions have come from.
2556          * @return Mixed Array of Title objects of the pages from which cascading restrictions
2557          *     have come, false for none, or true if such restrictions exist, but $getPages
2558          *     was not set.  The restriction array is an array of each type, each of which
2559          *     contains a array of unique groups.
2560          */
2561         public function getCascadeProtectionSources( $getPages = true ) {
2562                 global $wgContLang;
2563                 $pagerestrictions = array();
2564
2565                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2566                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2567                 } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2568                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2569                 }
2570
2571                 wfProfileIn( __METHOD__ );
2572
2573                 $dbr = wfGetDB( DB_SLAVE );
2574
2575                 if ( $this->getNamespace() == NS_FILE ) {
2576                         $tables = array( 'imagelinks', 'page_restrictions' );
2577                         $where_clauses = array(
2578                                 'il_to' => $this->getDBkey(),
2579                                 'il_from=pr_page',
2580                                 'pr_cascade' => 1
2581                         );
2582                 } else {
2583                         $tables = array( 'templatelinks', 'page_restrictions' );
2584                         $where_clauses = array(
2585                                 'tl_namespace' => $this->getNamespace(),
2586                                 'tl_title' => $this->getDBkey(),
2587                                 'tl_from=pr_page',
2588                                 'pr_cascade' => 1
2589                         );
2590                 }
2591
2592                 if ( $getPages ) {
2593                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2594                                 'pr_expiry', 'pr_type', 'pr_level' );
2595                         $where_clauses[] = 'page_id=pr_page';
2596                         $tables[] = 'page';
2597                 } else {
2598                         $cols = array( 'pr_expiry' );
2599                 }
2600
2601                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2602
2603                 $sources = $getPages ? array() : false;
2604                 $now = wfTimestampNow();
2605                 $purgeExpired = false;
2606
2607                 foreach ( $res as $row ) {
2608                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2609                         if ( $expiry > $now ) {
2610                                 if ( $getPages ) {
2611                                         $page_id = $row->pr_page;
2612                                         $page_ns = $row->page_namespace;
2613                                         $page_title = $row->page_title;
2614                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2615                                         # Add groups needed for each restriction type if its not already there
2616                                         # Make sure this restriction type still exists
2617
2618                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2619                                                 $pagerestrictions[$row->pr_type] = array();
2620                                         }
2621
2622                                         if (
2623                                                 isset( $pagerestrictions[$row->pr_type] )
2624                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2625                                         ) {
2626                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2627                                         }
2628                                 } else {
2629                                         $sources = true;
2630                                 }
2631                         } else {
2632                                 // Trigger lazy purge of expired restrictions from the db
2633                                 $purgeExpired = true;
2634                         }
2635                 }
2636                 if ( $purgeExpired ) {
2637                         Title::purgeExpiredRestrictions();
2638                 }
2639
2640                 if ( $getPages ) {
2641                         $this->mCascadeSources = $sources;
2642                         $this->mCascadingRestrictions = $pagerestrictions;
2643                 } else {
2644                         $this->mHasCascadingRestrictions = $sources;
2645                 }
2646
2647                 wfProfileOut( __METHOD__ );
2648                 return array( $sources, $pagerestrictions );
2649         }
2650
2651         /**
2652          * Accessor/initialisation for mRestrictions
2653          *
2654          * @param string $action action that permission needs to be checked for
2655          * @return Array of Strings the array of groups allowed to edit this article
2656          */
2657         public function getRestrictions( $action ) {
2658                 if ( !$this->mRestrictionsLoaded ) {
2659                         $this->loadRestrictions();
2660                 }
2661                 return isset( $this->mRestrictions[$action] )
2662                                 ? $this->mRestrictions[$action]
2663                                 : array();
2664         }
2665
2666         /**
2667          * Get the expiry time for the restriction against a given action
2668          *
2669          * @param $action
2670          * @return String|Bool 14-char timestamp, or 'infinity' if the page is protected forever
2671          *     or not protected at all, or false if the action is not recognised.
2672          */
2673         public function getRestrictionExpiry( $action ) {
2674                 if ( !$this->mRestrictionsLoaded ) {
2675                         $this->loadRestrictions();
2676                 }
2677                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2678         }
2679
2680         /**
2681          * Returns cascading restrictions for the current article
2682          *
2683          * @return Boolean
2684          */
2685         function areRestrictionsCascading() {
2686                 if ( !$this->mRestrictionsLoaded ) {
2687                         $this->loadRestrictions();
2688                 }
2689
2690                 return $this->mCascadeRestriction;
2691         }
2692
2693         /**
2694          * Loads a string into mRestrictions array
2695          *
2696          * @param $res Resource restrictions as an SQL result.
2697          * @param string $oldFashionedRestrictions comma-separated list of page
2698          *        restrictions from page table (pre 1.10)
2699          */
2700         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2701                 $rows = array();
2702
2703                 foreach ( $res as $row ) {
2704                         $rows[] = $row;
2705                 }
2706
2707                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2708         }
2709
2710         /**
2711          * Compiles list of active page restrictions from both page table (pre 1.10)
2712          * and page_restrictions table for this existing page.
2713          * Public for usage by LiquidThreads.
2714          *
2715          * @param array $rows of db result objects
2716          * @param string $oldFashionedRestrictions comma-separated list of page
2717          *        restrictions from page table (pre 1.10)
2718          */
2719         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2720                 global $wgContLang;
2721                 $dbr = wfGetDB( DB_SLAVE );
2722
2723                 $restrictionTypes = $this->getRestrictionTypes();
2724
2725                 foreach ( $restrictionTypes as $type ) {
2726                         $this->mRestrictions[$type] = array();
2727                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2728                 }
2729
2730                 $this->mCascadeRestriction = false;
2731
2732                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2733
2734                 if ( $oldFashionedRestrictions === null ) {
2735                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2736                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2737                 }
2738
2739                 if ( $oldFashionedRestrictions != '' ) {
2740
2741                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2742                                 $temp = explode( '=', trim( $restrict ) );
2743                                 if ( count( $temp ) == 1 ) {
2744                                         // old old format should be treated as edit/move restriction
2745                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2746                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2747                                 } else {
2748                                         $restriction = trim( $temp[1] );
2749                                         if ( $restriction != '' ) { //some old entries are empty
2750                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2751                                         }
2752                                 }
2753                         }
2754
2755                         $this->mOldRestrictions = true;
2756
2757                 }
2758
2759                 if ( count( $rows ) ) {
2760                         # Current system - load second to make them override.
2761                         $now = wfTimestampNow();
2762                         $purgeExpired = false;
2763
2764                         # Cycle through all the restrictions.
2765                         foreach ( $rows as $row ) {
2766
2767                                 // Don't take care of restrictions types that aren't allowed
2768                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2769                                         continue;
2770                                 }
2771
2772                                 // This code should be refactored, now that it's being used more generally,
2773                                 // But I don't really see any harm in leaving it in Block for now -werdna
2774                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2775
2776                                 // Only apply the restrictions if they haven't expired!
2777                                 if ( !$expiry || $expiry > $now ) {
2778                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2779                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2780
2781                                         $this->mCascadeRestriction |= $row->pr_cascade;
2782                                 } else {
2783                                         // Trigger a lazy purge of expired restrictions
2784                                         $purgeExpired = true;
2785                                 }
2786                         }
2787
2788                         if ( $purgeExpired ) {
2789                                 Title::purgeExpiredRestrictions();
2790                         }
2791                 }
2792
2793                 $this->mRestrictionsLoaded = true;
2794         }
2795
2796         /**
2797          * Load restrictions from the page_restrictions table
2798          *
2799          * @param string $oldFashionedRestrictions comma-separated list of page
2800          *        restrictions from page table (pre 1.10)
2801          */
2802         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2803                 global $wgContLang;
2804                 if ( !$this->mRestrictionsLoaded ) {
2805                         if ( $this->exists() ) {
2806                                 $dbr = wfGetDB( DB_SLAVE );
2807
2808                                 $res = $dbr->select(
2809                                         'page_restrictions',
2810                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2811                                         array( 'pr_page' => $this->getArticleID() ),
2812                                         __METHOD__
2813                                 );
2814
2815                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2816                         } else {
2817                                 $title_protection = $this->getTitleProtection();
2818
2819                                 if ( $title_protection ) {
2820                                         $now = wfTimestampNow();
2821                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2822
2823                                         if ( !$expiry || $expiry > $now ) {
2824                                                 // Apply the restrictions
2825                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2826                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2827                                         } else { // Get rid of the old restrictions
2828                                                 Title::purgeExpiredRestrictions();
2829                                                 $this->mTitleProtection = false;
2830                                         }
2831                                 } else {
2832                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2833                                 }
2834                                 $this->mRestrictionsLoaded = true;
2835                         }
2836                 }
2837         }
2838
2839         /**
2840          * Flush the protection cache in this object and force reload from the database.
2841          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2842          */
2843         public function flushRestrictions() {
2844                 $this->mRestrictionsLoaded = false;
2845                 $this->mTitleProtection = null;
2846         }
2847
2848         /**
2849          * Purge expired restrictions from the page_restrictions table
2850          */
2851         static function purgeExpiredRestrictions() {
2852                 if ( wfReadOnly() ) {
2853                         return;
2854                 }
2855
2856                 $method = __METHOD__;
2857                 $dbw = wfGetDB( DB_MASTER );
2858                 $dbw->onTransactionIdle( function() use ( $dbw, $method ) {
2859                         $dbw->delete(
2860                                 'page_restrictions',
2861                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2862                                 $method
2863                         );
2864                         $dbw->delete(
2865                                 'protected_titles',
2866                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2867                                 $method
2868                         );
2869                 } );
2870         }
2871
2872         /**
2873          * Does this have subpages?  (Warning, usually requires an extra DB query.)
2874          *
2875          * @return Bool
2876          */
2877         public function hasSubpages() {
2878                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
2879                         # Duh
2880                         return false;
2881                 }
2882
2883                 # We dynamically add a member variable for the purpose of this method
2884                 # alone to cache the result.  There's no point in having it hanging
2885                 # around uninitialized in every Title object; therefore we only add it
2886                 # if needed and don't declare it statically.
2887                 if ( isset( $this->mHasSubpages ) ) {
2888                         return $this->mHasSubpages;
2889                 }
2890
2891                 $subpages = $this->getSubpages( 1 );
2892                 if ( $subpages instanceof TitleArray ) {
2893                         return $this->mHasSubpages = (bool)$subpages->count();
2894                 }
2895                 return $this->mHasSubpages = false;
2896         }
2897
2898         /**
2899          * Get all subpages of this page.
2900          *
2901          * @param int $limit maximum number of subpages to fetch; -1 for no limit
2902          * @return mixed TitleArray, or empty array if this page's namespace
2903          *  doesn't allow subpages
2904          */
2905         public function getSubpages( $limit = -1 ) {
2906                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
2907                         return array();
2908                 }
2909
2910                 $dbr = wfGetDB( DB_SLAVE );
2911                 $conds['page_namespace'] = $this->getNamespace();
2912                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
2913                 $options = array();
2914                 if ( $limit > -1 ) {
2915                         $options['LIMIT'] = $limit;
2916                 }
2917                 return $this->mSubpages = TitleArray::newFromResult(
2918                         $dbr->select( 'page',
2919                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
2920                                 $conds,
2921                                 __METHOD__,
2922                                 $options
2923                         )
2924                 );
2925         }
2926
2927         /**
2928          * Is there a version of this page in the deletion archive?
2929          *
2930          * @return Int the number of archived revisions
2931          */
2932         public function isDeleted() {
2933                 if ( $this->getNamespace() < 0 ) {
2934                         $n = 0;
2935                 } else {
2936                         $dbr = wfGetDB( DB_SLAVE );
2937
2938                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
2939                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2940                                 __METHOD__
2941                         );
2942                         if ( $this->getNamespace() == NS_FILE ) {
2943                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
2944                                         array( 'fa_name' => $this->getDBkey() ),
2945                                         __METHOD__
2946                                 );
2947                         }
2948                 }
2949                 return (int)$n;
2950         }
2951
2952         /**
2953          * Is there a version of this page in the deletion archive?
2954          *
2955          * @return Boolean
2956          */
2957         public function isDeletedQuick() {
2958                 if ( $this->getNamespace() < 0 ) {
2959                         return false;
2960                 }
2961                 $dbr = wfGetDB( DB_SLAVE );
2962                 $deleted = (bool)$dbr->selectField( 'archive', '1',
2963                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2964                         __METHOD__
2965                 );
2966                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
2967                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
2968                                 array( 'fa_name' => $this->getDBkey() ),
2969                                 __METHOD__
2970                         );
2971                 }
2972                 return $deleted;
2973         }
2974
2975         /**
2976          * Get the article ID for this Title from the link cache,
2977          * adding it if necessary
2978          *
2979          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select
2980          *  for update
2981          * @return Int the ID
2982          */
2983         public function getArticleID( $flags = 0 ) {
2984                 if ( $this->getNamespace() < 0 ) {
2985                         return $this->mArticleID = 0;
2986                 }
2987                 $linkCache = LinkCache::singleton();
2988                 if ( $flags & self::GAID_FOR_UPDATE ) {
2989                         $oldUpdate = $linkCache->forUpdate( true );
2990                         $linkCache->clearLink( $this );
2991                         $this->mArticleID = $linkCache->addLinkObj( $this );
2992                         $linkCache->forUpdate( $oldUpdate );
2993                 } else {
2994                         if ( -1 == $this->mArticleID ) {
2995                                 $this->mArticleID = $linkCache->addLinkObj( $this );
2996                         }
2997                 }
2998                 return $this->mArticleID;
2999         }
3000
3001         /**
3002          * Is this an article that is a redirect page?
3003          * Uses link cache, adding it if necessary
3004          *
3005          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3006          * @return Bool
3007          */
3008         public function isRedirect( $flags = 0 ) {
3009                 if ( !is_null( $this->mRedirect ) ) {
3010                         return $this->mRedirect;
3011                 }
3012                 # Calling getArticleID() loads the field from cache as needed
3013                 if ( !$this->getArticleID( $flags ) ) {
3014                         return $this->mRedirect = false;
3015                 }
3016
3017                 $linkCache = LinkCache::singleton();
3018                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3019                 if ( $cached === null ) {
3020                         # Trust LinkCache's state over our own
3021                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3022                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3023                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3024                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3025                         # LinkCache to refresh its data from the master.
3026                         return $this->mRedirect = false;
3027                 }
3028
3029                 $this->mRedirect = (bool)$cached;
3030
3031                 return $this->mRedirect;
3032         }
3033
3034         /**
3035          * What is the length of this page?
3036          * Uses link cache, adding it if necessary
3037          *
3038          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3039          * @return Int
3040          */
3041         public function getLength( $flags = 0 ) {
3042                 if ( $this->mLength != -1 ) {
3043                         return $this->mLength;
3044                 }
3045                 # Calling getArticleID() loads the field from cache as needed
3046                 if ( !$this->getArticleID( $flags ) ) {
3047                         return $this->mLength = 0;
3048                 }
3049                 $linkCache = LinkCache::singleton();
3050                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3051                 if ( $cached === null ) {
3052                         # Trust LinkCache's state over our own, as for isRedirect()
3053                         return $this->mLength = 0;
3054                 }
3055
3056                 $this->mLength = intval( $cached );
3057
3058                 return $this->mLength;
3059         }
3060
3061         /**
3062          * What is the page_latest field for this page?
3063          *
3064          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3065          * @return Int or 0 if the page doesn't exist
3066          */
3067         public function getLatestRevID( $flags = 0 ) {
3068                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3069                         return intval( $this->mLatestID );
3070                 }
3071                 # Calling getArticleID() loads the field from cache as needed
3072                 if ( !$this->getArticleID( $flags ) ) {
3073                         return $this->mLatestID = 0;
3074                 }
3075                 $linkCache = LinkCache::singleton();
3076                 $linkCache->addLinkObj( $this );
3077                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3078                 if ( $cached === null ) {
3079                         # Trust LinkCache's state over our own, as for isRedirect()
3080                         return $this->mLatestID = 0;
3081                 }
3082
3083                 $this->mLatestID = intval( $cached );
3084
3085                 return $this->mLatestID;
3086         }
3087
3088         /**
3089          * This clears some fields in this object, and clears any associated
3090          * keys in the "bad links" section of the link cache.
3091          *
3092          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3093          * loading of the new page_id. It's also called from
3094          * WikiPage::doDeleteArticleReal()
3095          *
3096          * @param int $newid the new Article ID
3097          */
3098         public function resetArticleID( $newid ) {
3099                 $linkCache = LinkCache::singleton();
3100                 $linkCache->clearLink( $this );
3101
3102                 if ( $newid === false ) {
3103                         $this->mArticleID = -1;
3104                 } else {
3105                         $this->mArticleID = intval( $newid );
3106                 }
3107                 $this->mRestrictionsLoaded = false;
3108                 $this->mRestrictions = array();
3109                 $this->mRedirect = null;
3110                 $this->mLength = -1;
3111                 $this->mLatestID = false;
3112                 $this->mContentModel = false;
3113                 $this->mEstimateRevisions = null;
3114                 $this->mPageLanguage = false;
3115         }
3116
3117         /**
3118          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3119          *
3120          * @param string $text containing title to capitalize
3121          * @param int $ns namespace index, defaults to NS_MAIN
3122          * @return String containing capitalized title
3123          */
3124         public static function capitalize( $text, $ns = NS_MAIN ) {
3125                 global $wgContLang;
3126
3127                 if ( MWNamespace::isCapitalized( $ns ) ) {
3128                         return $wgContLang->ucfirst( $text );
3129                 } else {
3130                         return $text;
3131                 }
3132         }
3133
3134         /**
3135          * Secure and split - main initialisation function for this object
3136          *
3137          * Assumes that mDbkeyform has been set, and is urldecoded
3138          * and uses underscores, but not otherwise munged.  This function
3139          * removes illegal characters, splits off the interwiki and
3140          * namespace prefixes, sets the other forms, and canonicalizes
3141          * everything.
3142          *
3143          * @return Bool true on success
3144          */
3145         private function secureAndSplit() {
3146                 global $wgContLang, $wgLocalInterwiki;
3147
3148                 # Initialisation
3149                 $this->mInterwiki = $this->mFragment = '';
3150                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3151
3152                 $dbkey = $this->mDbkeyform;
3153
3154                 # Strip Unicode bidi override characters.
3155                 # Sometimes they slip into cut-n-pasted page titles, where the
3156                 # override chars get included in list displays.
3157                 $dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );
3158
3159                 # Clean up whitespace
3160                 # Note: use of the /u option on preg_replace here will cause
3161                 # input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
3162                 # conveniently disabling them.
3163                 $dbkey = preg_replace( '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u', '_', $dbkey );
3164                 $dbkey = trim( $dbkey, '_' );
3165
3166                 if ( $dbkey == '' ) {
3167                         return false;
3168                 }
3169
3170                 if ( strpos( $dbkey, UTF8_REPLACEMENT ) !== false ) {
3171                         # Contained illegal UTF-8 sequences or forbidden Unicode chars.
3172                         return false;
3173                 }
3174
3175                 $this->mDbkeyform = $dbkey;
3176
3177                 # Initial colon indicates main namespace rather than specified default
3178                 # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
3179                 if ( ':' == $dbkey[0] ) {
3180                         $this->mNamespace = NS_MAIN;
3181                         $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
3182                         $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
3183                 }
3184
3185                 # Namespace or interwiki prefix
3186                 $firstPass = true;
3187                 $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
3188                 do {
3189                         $m = array();
3190                         if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
3191                                 $p = $m[1];
3192                                 if ( ( $ns = $wgContLang->getNsIndex( $p ) ) !== false ) {
3193                                         # Ordinary namespace
3194                                         $dbkey = $m[2];
3195                                         $this->mNamespace = $ns;
3196                                         # For Talk:X pages, check if X has a "namespace" prefix
3197                                         if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
3198                                                 if ( $wgContLang->getNsIndex( $x[1] ) ) {
3199                                                         # Disallow Talk:File:x type titles...
3200                                                         return false;
3201                                                 } elseif ( Interwiki::isValidInterwiki( $x[1] ) ) {
3202                                                         # Disallow Talk:Interwiki:x type titles...
3203                                                         return false;
3204                                                 }
3205                                         }
3206                                 } elseif ( Interwiki::isValidInterwiki( $p ) ) {
3207                                         if ( !$firstPass ) {
3208                                                 # Can't make a local interwiki link to an interwiki link.
3209                                                 # That's just crazy!
3210                                                 return false;
3211                                         }
3212
3213                                         # Interwiki link
3214                                         $dbkey = $m[2];
3215                                         $this->mInterwiki = $wgContLang->lc( $p );
3216
3217                                         # Redundant interwiki prefix to the local wiki
3218                                         if ( $wgLocalInterwiki !== false
3219                                                 && 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki ) )
3220                                         {
3221                                                 if ( $dbkey == '' ) {
3222                                                         # Can't have an empty self-link
3223                                                         return false;
3224                                                 }
3225                                                 $this->mInterwiki = '';
3226                                                 $firstPass = false;
3227                                                 # Do another namespace split...
3228                                                 continue;
3229                                         }
3230
3231                                         # If there's an initial colon after the interwiki, that also
3232                                         # resets the default namespace
3233                                         if ( $dbkey !== '' && $dbkey[0] == ':' ) {
3234                                                 $this->mNamespace = NS_MAIN;
3235                                                 $dbkey = substr( $dbkey, 1 );
3236                                         }
3237                                 }
3238                                 # If there's no recognized interwiki or namespace,
3239                                 # then let the colon expression be part of the title.
3240                         }
3241                         break;
3242                 } while ( true );
3243
3244                 # We already know that some pages won't be in the database!
3245                 if ( $this->mInterwiki != '' || NS_SPECIAL == $this->mNamespace ) {
3246                         $this->mArticleID = 0;
3247                 }
3248                 $fragment = strstr( $dbkey, '#' );
3249                 if ( false !== $fragment ) {
3250                         $this->setFragment( $fragment );
3251                         $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
3252                         # remove whitespace again: prevents "Foo_bar_#"
3253                         # becoming "Foo_bar_"
3254                         $dbkey = preg_replace( '/_*$/', '', $dbkey );
3255                 }
3256
3257                 # Reject illegal characters.
3258                 $rxTc = self::getTitleInvalidRegex();
3259                 if ( preg_match( $rxTc, $dbkey ) ) {
3260                         return false;
3261                 }
3262
3263                 # Pages with "/./" or "/../" appearing in the URLs will often be un-
3264                 # reachable due to the way web browsers deal with 'relative' URLs.
3265                 # Also, they conflict with subpage syntax.  Forbid them explicitly.
3266                 if (
3267                         strpos( $dbkey, '.' ) !== false &&
3268                         (
3269                                 $dbkey === '.' || $dbkey === '..' ||
3270                                 strpos( $dbkey, './' ) === 0 ||
3271                                 strpos( $dbkey, '../' ) === 0 ||
3272                                 strpos( $dbkey, '/./' ) !== false ||
3273                                 strpos( $dbkey, '/../' ) !== false ||
3274                                 substr( $dbkey, -2 ) == '/.' ||
3275                                 substr( $dbkey, -3 ) == '/..'
3276                         )
3277                 ) {
3278                         return false;
3279                 }
3280
3281                 # Magic tilde sequences? Nu-uh!
3282                 if ( strpos( $dbkey, '~~~' ) !== false ) {
3283                         return false;
3284                 }
3285
3286                 # Limit the size of titles to 255 bytes. This is typically the size of the
3287                 # underlying database field. We make an exception for special pages, which
3288                 # don't need to be stored in the database, and may edge over 255 bytes due
3289                 # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
3290                 if (
3291                         ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 )
3292                         || strlen( $dbkey ) > 512
3293                 ) {
3294                         return false;
3295                 }
3296
3297                 # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
3298                 # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
3299                 # other site might be case-sensitive.
3300                 $this->mUserCaseDBKey = $dbkey;
3301                 if ( $this->mInterwiki == '' ) {
3302                         $dbkey = self::capitalize( $dbkey, $this->mNamespace );
3303                 }
3304
3305                 # Can't make a link to a namespace alone... "empty" local links can only be
3306                 # self-links with a fragment identifier.
3307                 # TODO: Why do we exclude NS_MAIN (bug 54044)
3308                 if ( $dbkey == '' && $this->mInterwiki == '' && $this->mNamespace != NS_MAIN ) {
3309                         return false;
3310                 }
3311
3312                 // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
3313                 // IP names are not allowed for accounts, and can only be referring to
3314                 // edits from the IP. Given '::' abbreviations and caps/lowercaps,
3315                 // there are numerous ways to present the same IP. Having sp:contribs scan
3316                 // them all is silly and having some show the edits and others not is
3317                 // inconsistent. Same for talk/userpages. Keep them normalized instead.
3318                 $dbkey = ( $this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK )
3319                         ? IP::sanitizeIP( $dbkey )
3320                         : $dbkey;
3321
3322                 // Any remaining initial :s are illegal.
3323                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3324                         return false;
3325                 }
3326
3327                 # Fill fields
3328                 $this->mDbkeyform = $dbkey;
3329                 $this->mUrlform = wfUrlencode( $dbkey );
3330
3331                 $this->mTextform = str_replace( '_', ' ', $dbkey );
3332
3333                 return true;
3334         }
3335
3336         /**
3337          * Get an array of Title objects linking to this Title
3338          * Also stores the IDs in the link cache.
3339          *
3340          * WARNING: do not use this function on arbitrary user-supplied titles!
3341          * On heavily-used templates it will max out the memory.
3342          *
3343          * @param array $options may be FOR UPDATE
3344          * @param string $table table name
3345          * @param string $prefix fields prefix
3346          * @return Array of Title objects linking here
3347          */
3348         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3349                 if ( count( $options ) > 0 ) {
3350                         $db = wfGetDB( DB_MASTER );
3351                 } else {
3352                         $db = wfGetDB( DB_SLAVE );
3353                 }
3354
3355                 $res = $db->select(
3356                         array( 'page', $table ),
3357                         self::getSelectFields(),
3358                         array(
3359                                 "{$prefix}_from=page_id",
3360                                 "{$prefix}_namespace" => $this->getNamespace(),
3361                                 "{$prefix}_title" => $this->getDBkey() ),
3362                         __METHOD__,
3363                         $options
3364                 );
3365
3366                 $retVal = array();
3367                 if ( $res->numRows() ) {
3368                         $linkCache = LinkCache::singleton();
3369                         foreach ( $res as $row ) {
3370                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3371                                 if ( $titleObj ) {
3372                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3373                                         $retVal[] = $titleObj;
3374                                 }
3375                         }
3376                 }
3377                 return $retVal;
3378         }
3379
3380         /**
3381          * Get an array of Title objects using this Title as a template
3382          * Also stores the IDs in the link cache.
3383          *
3384          * WARNING: do not use this function on arbitrary user-supplied titles!
3385          * On heavily-used templates it will max out the memory.
3386          *
3387          * @param array $options may be FOR UPDATE
3388          * @return Array of Title the Title objects linking here
3389          */
3390         public function getTemplateLinksTo( $options = array() ) {
3391                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3392         }
3393
3394         /**
3395          * Get an array of Title objects linked from this Title
3396          * Also stores the IDs in the link cache.
3397          *
3398          * WARNING: do not use this function on arbitrary user-supplied titles!
3399          * On heavily-used templates it will max out the memory.
3400          *
3401          * @param array $options may be FOR UPDATE
3402          * @param string $table table name
3403          * @param string $prefix fields prefix
3404          * @return Array of Title objects linking here
3405          */
3406         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3407                 global $wgContentHandlerUseDB;
3408
3409                 $id = $this->getArticleID();
3410
3411                 # If the page doesn't exist; there can't be any link from this page
3412                 if ( !$id ) {
3413                         return array();
3414                 }
3415
3416                 if ( count( $options ) > 0 ) {
3417                         $db = wfGetDB( DB_MASTER );
3418                 } else {
3419                         $db = wfGetDB( DB_SLAVE );
3420                 }
3421
3422                 $namespaceFiled = "{$prefix}_namespace";
3423                 $titleField = "{$prefix}_title";
3424
3425                 $fields = array( $namespaceFiled, $titleField, 'page_id', 'page_len', 'page_is_redirect', 'page_latest' );
3426                 if ( $wgContentHandlerUseDB ) {
3427                         $fields[] = 'page_content_model';
3428                 }
3429
3430                 $res = $db->select(
3431                         array( $table, 'page' ),
3432                         $fields,
3433                         array( "{$prefix}_from" => $id ),
3434                         __METHOD__,
3435                         $options,
3436                         array( 'page' => array( 'LEFT JOIN', array( "page_namespace=$namespaceFiled", "page_title=$titleField" ) ) )
3437                 );
3438
3439                 $retVal = array();
3440                 if ( $res->numRows() ) {
3441                         $linkCache = LinkCache::singleton();
3442                         foreach ( $res as $row ) {
3443                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3444                                 if ( $titleObj ) {
3445                                         if ( $row->page_id ) {
3446                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3447                                         } else {
3448                                                 $linkCache->addBadLinkObj( $titleObj );
3449                                         }
3450                                         $retVal[] = $titleObj;
3451                                 }
3452                         }
3453                 }
3454                 return $retVal;
3455         }
3456
3457         /**
3458          * Get an array of Title objects used on this Title as a template
3459          * Also stores the IDs in the link cache.
3460          *
3461          * WARNING: do not use this function on arbitrary user-supplied titles!
3462          * On heavily-used templates it will max out the memory.
3463          *
3464          * @param array $options may be FOR UPDATE
3465          * @return Array of Title the Title objects used here
3466          */
3467         public function getTemplateLinksFrom( $options = array() ) {
3468                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3469         }
3470
3471         /**
3472          * Get an array of Title objects referring to non-existent articles linked from this page
3473          *
3474          * @todo check if needed (used only in SpecialBrokenRedirects.php, and should use redirect table in this case)
3475          * @return Array of Title the Title objects
3476          */
3477         public function getBrokenLinksFrom() {
3478                 if ( $this->getArticleID() == 0 ) {
3479                         # All links from article ID 0 are false positives
3480                         return array();
3481                 }
3482
3483                 $dbr = wfGetDB( DB_SLAVE );
3484                 $res = $dbr->select(
3485                         array( 'page', 'pagelinks' ),
3486                         array( 'pl_namespace', 'pl_title' ),
3487                         array(
3488                                 'pl_from' => $this->getArticleID(),
3489                                 'page_namespace IS NULL'
3490                         ),
3491                         __METHOD__, array(),
3492                         array(
3493                                 'page' => array(
3494                                         'LEFT JOIN',
3495                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3496                                 )
3497                         )
3498                 );
3499
3500                 $retVal = array();
3501                 foreach ( $res as $row ) {
3502                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3503                 }
3504                 return $retVal;
3505         }
3506
3507         /**
3508          * Get a list of URLs to purge from the Squid cache when this
3509          * page changes
3510          *
3511          * @return Array of String the URLs
3512          */
3513         public function getSquidURLs() {
3514                 $urls = array(
3515                         $this->getInternalURL(),
3516                         $this->getInternalURL( 'action=history' )
3517                 );
3518
3519                 $pageLang = $this->getPageLanguage();
3520                 if ( $pageLang->hasVariants() ) {
3521                         $variants = $pageLang->getVariants();
3522                         foreach ( $variants as $vCode ) {
3523                                 $urls[] = $this->getInternalURL( '', $vCode );
3524                         }
3525                 }
3526
3527                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3528                 return $urls;
3529         }
3530
3531         /**
3532          * Purge all applicable Squid URLs
3533          */
3534         public function purgeSquid() {
3535                 global $wgUseSquid;
3536                 if ( $wgUseSquid ) {
3537                         $urls = $this->getSquidURLs();
3538                         $u = new SquidUpdate( $urls );
3539                         $u->doUpdate();
3540                 }
3541         }
3542
3543         /**
3544          * Move this page without authentication
3545          *
3546          * @param $nt Title the new page Title
3547          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3548          */
3549         public function moveNoAuth( &$nt ) {
3550                 return $this->moveTo( $nt, false );
3551         }
3552
3553         /**
3554          * Check whether a given move operation would be valid.
3555          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3556          *
3557          * @param $nt Title the new title
3558          * @param bool $auth indicates whether $wgUser's permissions
3559          *  should be checked
3560          * @param string $reason is the log summary of the move, used for spam checking
3561          * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
3562          */
3563         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3564                 global $wgUser, $wgContentHandlerUseDB;
3565
3566                 $errors = array();
3567                 if ( !$nt ) {
3568                         // Normally we'd add this to $errors, but we'll get
3569                         // lots of syntax errors if $nt is not an object
3570                         return array( array( 'badtitletext' ) );
3571                 }
3572                 if ( $this->equals( $nt ) ) {
3573                         $errors[] = array( 'selfmove' );
3574                 }
3575                 if ( !$this->isMovable() ) {
3576                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3577                 }
3578                 if ( $nt->getInterwiki() != '' ) {
3579                         $errors[] = array( 'immobile-target-namespace-iw' );
3580                 }
3581                 if ( !$nt->isMovable() ) {
3582                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3583                 }
3584
3585                 $oldid = $this->getArticleID();
3586                 $newid = $nt->getArticleID();
3587
3588                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3589                         $errors[] = array( 'articleexists' );
3590                 }
3591                 if (
3592                         ( $this->getDBkey() == '' ) ||
3593                         ( !$oldid ) ||
3594                         ( $nt->getDBkey() == '' )
3595                 ) {
3596                         $errors[] = array( 'badarticleerror' );
3597                 }
3598
3599                 // Content model checks
3600                 if ( !$wgContentHandlerUseDB &&
3601                                 $this->getContentModel() !== $nt->getContentModel() ) {
3602                         // can't move a page if that would change the page's content model
3603                         $errors[] = array(
3604                                 'bad-target-model',
3605                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3606                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3607                         );
3608                 }
3609
3610                 // Image-specific checks
3611                 if ( $this->getNamespace() == NS_FILE ) {
3612                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3613                 }
3614
3615                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3616                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3617                 }
3618
3619                 if ( $auth ) {
3620                         $errors = wfMergeErrorArrays( $errors,
3621                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3622                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3623                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3624                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3625                 }
3626
3627                 $match = EditPage::matchSummarySpamRegex( $reason );
3628                 if ( $match !== false ) {
3629                         // This is kind of lame, won't display nice
3630                         $errors[] = array( 'spamprotectiontext' );
3631                 }
3632
3633                 $err = null;
3634                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3635                         $errors[] = array( 'hookaborted', $err );
3636                 }
3637
3638                 # The move is allowed only if (1) the target doesn't exist, or
3639                 # (2) the target is a redirect to the source, and has no history
3640                 # (so we can undo bad moves right after they're done).
3641
3642                 if ( 0 != $newid ) { # Target exists; check for validity
3643                         if ( !$this->isValidMoveTarget( $nt ) ) {
3644                                 $errors[] = array( 'articleexists' );
3645                         }
3646                 } else {
3647                         $tp = $nt->getTitleProtection();
3648                         $right = $tp['pt_create_perm'];
3649                         if ( $right == 'sysop' ) {
3650                                 $right = 'editprotected'; // B/C
3651                         }
3652                         if ( $right == 'autoconfirmed' ) {
3653                                 $right = 'editsemiprotected'; // B/C
3654                         }
3655                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3656                                 $errors[] = array( 'cantmove-titleprotected' );
3657                         }
3658                 }
3659                 if ( empty( $errors ) ) {
3660                         return true;
3661                 }
3662                 return $errors;
3663         }
3664
3665         /**
3666          * Check if the requested move target is a valid file move target
3667          * @param Title $nt Target title
3668          * @return array List of errors
3669          */
3670         protected function validateFileMoveOperation( $nt ) {
3671                 global $wgUser;
3672
3673                 $errors = array();
3674
3675                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3676
3677                 $file = wfLocalFile( $this );
3678                 if ( $file->exists() ) {
3679                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3680                                 $errors[] = array( 'imageinvalidfilename' );
3681                         }
3682                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3683                                 $errors[] = array( 'imagetypemismatch' );
3684                         }
3685                 }
3686
3687                 if ( $nt->getNamespace() != NS_FILE ) {
3688                         $errors[] = array( 'imagenocrossnamespace' );
3689                         // From here we want to do checks on a file object, so if we can't
3690                         // create one, we must return.
3691                         return $errors;
3692                 }
3693
3694                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3695
3696                 $destFile = wfLocalFile( $nt );
3697                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3698                         $errors[] = array( 'file-exists-sharedrepo' );
3699                 }
3700
3701                 return $errors;
3702         }
3703
3704         /**
3705          * Move a title to a new location
3706          *
3707          * @param $nt Title the new title
3708          * @param bool $auth indicates whether $wgUser's permissions
3709          *  should be checked
3710          * @param string $reason the reason for the move
3711          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3712          *  Ignored if the user doesn't have the suppressredirect right.
3713          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3714          */
3715         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3716                 global $wgUser;
3717                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3718                 if ( is_array( $err ) ) {
3719                         // Auto-block user's IP if the account was "hard" blocked
3720                         $wgUser->spreadAnyEditBlock();
3721                         return $err;
3722                 }
3723                 // Check suppressredirect permission
3724                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3725                         $createRedirect = true;
3726                 }
3727
3728                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3729
3730                 // If it is a file, move it first.
3731                 // It is done before all other moving stuff is done because it's hard to revert.
3732                 $dbw = wfGetDB( DB_MASTER );
3733                 if ( $this->getNamespace() == NS_FILE ) {
3734                         $file = wfLocalFile( $this );
3735                         if ( $file->exists() ) {
3736                                 $status = $file->move( $nt );
3737                                 if ( !$status->isOk() ) {
3738                                         return $status->getErrorsArray();
3739                                 }
3740                         }
3741                         // Clear RepoGroup process cache
3742                         RepoGroup::singleton()->clearCache( $this );
3743                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3744                 }
3745
3746                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3747                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3748                 $protected = $this->isProtected();
3749
3750                 // Do the actual move
3751                 $this->moveToInternal( $nt, $reason, $createRedirect );
3752
3753                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3754                 // cl_timestamp, which may disturb time-based lists on some sites.
3755                 $prefixes = $dbw->select(
3756                         'categorylinks',
3757                         array( 'cl_sortkey_prefix', 'cl_to' ),
3758                         array( 'cl_from' => $pageid ),
3759                         __METHOD__
3760                 );
3761                 foreach ( $prefixes as $prefixRow ) {
3762                         $prefix = $prefixRow->cl_sortkey_prefix;
3763                         $catTo = $prefixRow->cl_to;
3764                         $dbw->update( 'categorylinks',
3765                                 array(
3766                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3767                                                 $nt->getCategorySortkey( $prefix ) ),
3768                                         'cl_timestamp=cl_timestamp' ),
3769                                 array(
3770                                         'cl_from' => $pageid,
3771                                         'cl_to' => $catTo ),
3772                                 __METHOD__
3773                         );
3774                 }
3775
3776                 $redirid = $this->getArticleID();
3777
3778                 if ( $protected ) {
3779                         # Protect the redirect title as the title used to be...
3780                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3781                                 array(
3782                                         'pr_page' => $redirid,
3783                                         'pr_type' => 'pr_type',
3784                                         'pr_level' => 'pr_level',
3785                                         'pr_cascade' => 'pr_cascade',
3786                                         'pr_user' => 'pr_user',
3787                                         'pr_expiry' => 'pr_expiry'
3788                                 ),
3789                                 array( 'pr_page' => $pageid ),
3790                                 __METHOD__,
3791                                 array( 'IGNORE' )
3792                         );
3793                         # Update the protection log
3794                         $log = new LogPage( 'protect' );
3795                         $comment = wfMessage(
3796                                 'prot_1movedto2',
3797                                 $this->getPrefixedText(),
3798                                 $nt->getPrefixedText()
3799                         )->inContentLanguage()->text();
3800                         if ( $reason ) {
3801                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3802                         }
3803                         // @todo FIXME: $params?
3804                         $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ), $wgUser );
3805                 }
3806
3807                 # Update watchlists
3808                 $oldnamespace = MWNamespace::getSubject( $this->getNamespace() );
3809                 $newnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3810                 $oldtitle = $this->getDBkey();
3811                 $newtitle = $nt->getDBkey();
3812
3813                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3814                         WatchedItem::duplicateEntries( $this, $nt );
3815                 }
3816
3817                 $dbw->commit( __METHOD__ );
3818
3819                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
3820                 return true;
3821         }
3822
3823         /**
3824          * Move page to a title which is either a redirect to the
3825          * source page or nonexistent
3826          *
3827          * @param $nt Title the page to move to, which should be a redirect or nonexistent
3828          * @param string $reason The reason for the move
3829          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3830          *   if the user has the suppressredirect right
3831          * @throws MWException
3832          */
3833         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3834                 global $wgUser, $wgContLang;
3835
3836                 if ( $nt->exists() ) {
3837                         $moveOverRedirect = true;
3838                         $logType = 'move_redir';
3839                 } else {
3840                         $moveOverRedirect = false;
3841                         $logType = 'move';
3842                 }
3843
3844                 if ( $createRedirect ) {
3845                         $contentHandler = ContentHandler::getForTitle( $this );
3846                         $redirectContent = $contentHandler->makeRedirectContent( $nt,
3847                                 wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3848
3849                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3850                 } else {
3851                         $redirectContent = null;
3852                 }
3853
3854                 $logEntry = new ManualLogEntry( 'move', $logType );
3855                 $logEntry->setPerformer( $wgUser );
3856                 $logEntry->setTarget( $this );
3857                 $logEntry->setComment( $reason );
3858                 $logEntry->setParameters( array(
3859                         '4::target' => $nt->getPrefixedText(),
3860                         '5::noredir' => $redirectContent ? '0': '1',
3861                 ) );
3862
3863                 $formatter = LogFormatter::newFromEntry( $logEntry );
3864                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3865                 $comment = $formatter->getPlainActionText();
3866                 if ( $reason ) {
3867                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3868                 }
3869                 # Truncate for whole multibyte characters.
3870                 $comment = $wgContLang->truncate( $comment, 255 );
3871
3872                 $oldid = $this->getArticleID();
3873
3874                 $dbw = wfGetDB( DB_MASTER );
3875
3876                 $newpage = WikiPage::factory( $nt );
3877
3878                 if ( $moveOverRedirect ) {
3879                         $newid = $nt->getArticleID();
3880
3881                         # Delete the old redirect. We don't save it to history since
3882                         # by definition if we've got here it's rather uninteresting.
3883                         # We have to remove it so that the next step doesn't trigger
3884                         # a conflict on the unique namespace+title index...
3885                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3886
3887                         $newpage->doDeleteUpdates( $newid );
3888                 }
3889
3890                 # Save a null revision in the page's history notifying of the move
3891                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
3892                 if ( !is_object( $nullRevision ) ) {
3893                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3894                 }
3895
3896                 $nullRevision->insertOn( $dbw );
3897
3898                 # Change the name of the target page:
3899                 $dbw->update( 'page',
3900                         /* SET */ array(
3901                                 'page_namespace' => $nt->getNamespace(),
3902                                 'page_title' => $nt->getDBkey(),
3903                         ),
3904                         /* WHERE */ array( 'page_id' => $oldid ),
3905                         __METHOD__
3906                 );
3907
3908                 // clean up the old title before reset article id - bug 45348
3909                 if ( !$redirectContent ) {
3910                         WikiPage::onArticleDelete( $this );
3911                 }
3912
3913                 $this->resetArticleID( 0 ); // 0 == non existing
3914                 $nt->resetArticleID( $oldid );
3915                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
3916
3917                 $newpage->updateRevisionOn( $dbw, $nullRevision );
3918
3919                 wfRunHooks( 'NewRevisionFromEditComplete',
3920                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
3921
3922                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
3923
3924                 if ( !$moveOverRedirect ) {
3925                         WikiPage::onArticleCreate( $nt );
3926                 }
3927
3928                 # Recreate the redirect, this time in the other direction.
3929                 if ( $redirectContent ) {
3930                         $redirectArticle = WikiPage::factory( $this );
3931                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
3932                         $newid = $redirectArticle->insertOn( $dbw );
3933                         if ( $newid ) { // sanity
3934                                 $this->resetArticleID( $newid );
3935                                 $redirectRevision = new Revision( array(
3936                                         'title' => $this, // for determining the default content model
3937                                         'page' => $newid,
3938                                         'comment' => $comment,
3939                                         'content' => $redirectContent ) );
3940                                 $redirectRevision->insertOn( $dbw );
3941                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
3942
3943                                 wfRunHooks( 'NewRevisionFromEditComplete',
3944                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
3945
3946                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
3947                         }
3948                 }
3949
3950                 # Log the move
3951                 $logid = $logEntry->insert();
3952                 $logEntry->publish( $logid );
3953         }
3954
3955         /**
3956          * Move this page's subpages to be subpages of $nt
3957          *
3958          * @param $nt Title Move target
3959          * @param bool $auth Whether $wgUser's permissions should be checked
3960          * @param string $reason The reason for the move
3961          * @param bool $createRedirect Whether to create redirects from the old subpages to
3962          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3963          * @return mixed array with old page titles as keys, and strings (new page titles) or
3964          *     arrays (errors) as values, or an error array with numeric indices if no pages
3965          *     were moved
3966          */
3967         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3968                 global $wgMaximumMovedPages;
3969                 // Check permissions
3970                 if ( !$this->userCan( 'move-subpages' ) ) {
3971                         return array( 'cant-move-subpages' );
3972                 }
3973                 // Do the source and target namespaces support subpages?
3974                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3975                         return array( 'namespace-nosubpages',
3976                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3977                 }
3978                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3979                         return array( 'namespace-nosubpages',
3980                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3981                 }
3982
3983                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3984                 $retval = array();
3985                 $count = 0;
3986                 foreach ( $subpages as $oldSubpage ) {
3987                         $count++;
3988                         if ( $count > $wgMaximumMovedPages ) {
3989                                 $retval[$oldSubpage->getPrefixedTitle()] =
3990                                                 array( 'movepage-max-pages',
3991                                                         $wgMaximumMovedPages );
3992                                 break;
3993                         }
3994
3995                         // We don't know whether this function was called before
3996                         // or after moving the root page, so check both
3997                         // $this and $nt
3998                         if ( $oldSubpage->getArticleID() == $this->getArticleID() ||
3999                                         $oldSubpage->getArticleID() == $nt->getArticleID() )
4000                         {
4001                                 // When moving a page to a subpage of itself,
4002                                 // don't move it twice
4003                                 continue;
4004                         }
4005                         $newPageName = preg_replace(
4006                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4007                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4008                                         $oldSubpage->getDBkey() );
4009                         if ( $oldSubpage->isTalkPage() ) {
4010                                 $newNs = $nt->getTalkPage()->getNamespace();
4011                         } else {
4012                                 $newNs = $nt->getSubjectPage()->getNamespace();
4013                         }
4014                         # Bug 14385: we need makeTitleSafe because the new page names may
4015                         # be longer than 255 characters.
4016                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4017
4018                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4019                         if ( $success === true ) {
4020                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4021                         } else {
4022                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4023                         }
4024                 }
4025                 return $retval;
4026         }
4027
4028         /**
4029          * Checks if this page is just a one-rev redirect.
4030          * Adds lock, so don't use just for light purposes.
4031          *
4032          * @return Bool
4033          */
4034         public function isSingleRevRedirect() {
4035                 global $wgContentHandlerUseDB;
4036
4037                 $dbw = wfGetDB( DB_MASTER );
4038
4039                 # Is it a redirect?
4040                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4041                 if ( $wgContentHandlerUseDB ) {
4042                         $fields[] = 'page_content_model';
4043                 }
4044
4045                 $row = $dbw->selectRow( 'page',
4046                         $fields,
4047                         $this->pageCond(),
4048                         __METHOD__,
4049                         array( 'FOR UPDATE' )
4050                 );
4051                 # Cache some fields we may want
4052                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4053                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4054                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4055                 $this->mContentModel = $row && isset( $row->page_content_model ) ? strval( $row->page_content_model ) : false;
4056                 if ( !$this->mRedirect ) {
4057                         return false;
4058                 }
4059                 # Does the article have a history?
4060                 $row = $dbw->selectField( array( 'page', 'revision' ),
4061                         'rev_id',
4062                         array( 'page_namespace' => $this->getNamespace(),
4063                                 'page_title' => $this->getDBkey(),
4064                                 'page_id=rev_page',
4065                                 'page_latest != rev_id'
4066                         ),
4067                         __METHOD__,
4068                         array( 'FOR UPDATE' )
4069                 );
4070                 # Return true if there was no history
4071                 return ( $row === false );
4072         }
4073
4074         /**
4075          * Checks if $this can be moved to a given Title
4076          * - Selects for update, so don't call it unless you mean business
4077          *
4078          * @param $nt Title the new title to check
4079          * @return Bool
4080          */
4081         public function isValidMoveTarget( $nt ) {
4082                 # Is it an existing file?
4083                 if ( $nt->getNamespace() == NS_FILE ) {
4084                         $file = wfLocalFile( $nt );
4085                         if ( $file->exists() ) {
4086                                 wfDebug( __METHOD__ . ": file exists\n" );
4087                                 return false;
4088                         }
4089                 }
4090                 # Is it a redirect with no history?
4091                 if ( !$nt->isSingleRevRedirect() ) {
4092                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4093                         return false;
4094                 }
4095                 # Get the article text
4096                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4097                 if ( !is_object( $rev ) ) {
4098                         return false;
4099                 }
4100                 $content = $rev->getContent();
4101                 # Does the redirect point to the source?
4102                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4103                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4104
4105                 if ( $redirTitle ) {
4106                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4107                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4108                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4109                                 return false;
4110                         } else {
4111                                 return true;
4112                         }
4113                 } else {
4114                         # Fail safe (not a redirect after all. strange.)
4115                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4116                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4117                         return false;
4118                 }
4119         }
4120
4121         /**
4122          * Get categories to which this Title belongs and return an array of
4123          * categories' names.
4124          *
4125          * @return Array of parents in the form:
4126          *        $parent => $currentarticle
4127          */
4128         public function getParentCategories() {
4129                 global $wgContLang;
4130
4131                 $data = array();
4132
4133                 $titleKey = $this->getArticleID();
4134
4135                 if ( $titleKey === 0 ) {
4136                         return $data;
4137                 }
4138
4139                 $dbr = wfGetDB( DB_SLAVE );
4140
4141                 $res = $dbr->select(
4142                         'categorylinks',
4143                         'cl_to',
4144                         array( 'cl_from' => $titleKey ),
4145                         __METHOD__
4146                 );
4147
4148                 if ( $res->numRows() > 0 ) {
4149                         foreach ( $res as $row ) {
4150                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4151                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4152                         }
4153                 }
4154                 return $data;
4155         }
4156
4157         /**
4158          * Get a tree of parent categories
4159          *
4160          * @param array $children with the children in the keys, to check for circular refs
4161          * @return Array Tree of parent categories
4162          */
4163         public function getParentCategoryTree( $children = array() ) {
4164                 $stack = array();
4165                 $parents = $this->getParentCategories();
4166
4167                 if ( $parents ) {
4168                         foreach ( $parents as $parent => $current ) {
4169                                 if ( array_key_exists( $parent, $children ) ) {
4170                                         # Circular reference
4171                                         $stack[$parent] = array();
4172                                 } else {
4173                                         $nt = Title::newFromText( $parent );
4174                                         if ( $nt ) {
4175                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4176                                         }
4177                                 }
4178                         }
4179                 }
4180
4181                 return $stack;
4182         }
4183
4184         /**
4185          * Get an associative array for selecting this title from
4186          * the "page" table
4187          *
4188          * @return Array suitable for the $where parameter of DB::select()
4189          */
4190         public function pageCond() {
4191                 if ( $this->mArticleID > 0 ) {
4192                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4193                         return array( 'page_id' => $this->mArticleID );
4194                 } else {
4195                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4196                 }
4197         }
4198
4199         /**
4200          * Get the revision ID of the previous revision
4201          *
4202          * @param int $revId Revision ID. Get the revision that was before this one.
4203          * @param int $flags Title::GAID_FOR_UPDATE
4204          * @return Int|Bool Old revision ID, or FALSE if none exists
4205          */
4206         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4207                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4208                 $revId = $db->selectField( 'revision', 'rev_id',
4209                         array(
4210                                 'rev_page' => $this->getArticleID( $flags ),
4211                                 'rev_id < ' . intval( $revId )
4212                         ),
4213                         __METHOD__,
4214                         array( 'ORDER BY' => 'rev_id DESC' )
4215                 );
4216
4217                 if ( $revId === false ) {
4218                         return false;
4219                 } else {
4220                         return intval( $revId );
4221                 }
4222         }
4223
4224         /**
4225          * Get the revision ID of the next revision
4226          *
4227          * @param int $revId Revision ID. Get the revision that was after this one.
4228          * @param int $flags Title::GAID_FOR_UPDATE
4229          * @return Int|Bool Next revision ID, or FALSE if none exists
4230          */
4231         public function getNextRevisionID( $revId, $flags = 0 ) {
4232                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4233                 $revId = $db->selectField( 'revision', 'rev_id',
4234                         array(
4235                                 'rev_page' => $this->getArticleID( $flags ),
4236                                 'rev_id > ' . intval( $revId )
4237                         ),
4238                         __METHOD__,
4239                         array( 'ORDER BY' => 'rev_id' )
4240                 );
4241
4242                 if ( $revId === false ) {
4243                         return false;
4244                 } else {
4245                         return intval( $revId );
4246                 }
4247         }
4248
4249         /**
4250          * Get the first revision of the page
4251          *
4252          * @param int $flags Title::GAID_FOR_UPDATE
4253          * @return Revision|Null if page doesn't exist
4254          */
4255         public function getFirstRevision( $flags = 0 ) {
4256                 $pageId = $this->getArticleID( $flags );
4257                 if ( $pageId ) {
4258                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4259                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4260                                 array( 'rev_page' => $pageId ),
4261                                 __METHOD__,
4262                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4263                         );
4264                         if ( $row ) {
4265                                 return new Revision( $row );
4266                         }
4267                 }
4268                 return null;
4269         }
4270
4271         /**
4272          * Get the oldest revision timestamp of this page
4273          *
4274          * @param int $flags Title::GAID_FOR_UPDATE
4275          * @return String: MW timestamp
4276          */
4277         public function getEarliestRevTime( $flags = 0 ) {
4278                 $rev = $this->getFirstRevision( $flags );
4279                 return $rev ? $rev->getTimestamp() : null;
4280         }
4281
4282         /**
4283          * Check if this is a new page
4284          *
4285          * @return bool
4286          */
4287         public function isNewPage() {
4288                 $dbr = wfGetDB( DB_SLAVE );
4289                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4290         }
4291
4292         /**
4293          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4294          *
4295          * @return bool
4296          */
4297         public function isBigDeletion() {
4298                 global $wgDeleteRevisionsLimit;
4299
4300                 if ( !$wgDeleteRevisionsLimit ) {
4301                         return false;
4302                 }
4303
4304                 $revCount = $this->estimateRevisionCount();
4305                 return $revCount > $wgDeleteRevisionsLimit;
4306         }
4307
4308         /**
4309          * Get the  approximate revision count of this page.
4310          *
4311          * @return int
4312          */
4313         public function estimateRevisionCount() {
4314                 if ( !$this->exists() ) {
4315                         return 0;
4316                 }
4317
4318                 if ( $this->mEstimateRevisions === null ) {
4319                         $dbr = wfGetDB( DB_SLAVE );
4320                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4321                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4322                 }
4323
4324                 return $this->mEstimateRevisions;
4325         }
4326
4327         /**
4328          * Get the number of revisions between the given revision.
4329          * Used for diffs and other things that really need it.
4330          *
4331          * @param int|Revision $old Old revision or rev ID (first before range)
4332          * @param int|Revision $new New revision or rev ID (first after range)
4333          * @return Int Number of revisions between these revisions.
4334          */
4335         public function countRevisionsBetween( $old, $new ) {
4336                 if ( !( $old instanceof Revision ) ) {
4337                         $old = Revision::newFromTitle( $this, (int)$old );
4338                 }
4339                 if ( !( $new instanceof Revision ) ) {
4340                         $new = Revision::newFromTitle( $this, (int)$new );
4341                 }
4342                 if ( !$old || !$new ) {
4343                         return 0; // nothing to compare
4344                 }
4345                 $dbr = wfGetDB( DB_SLAVE );
4346                 return (int)$dbr->selectField( 'revision', 'count(*)',
4347                         array(
4348                                 'rev_page' => $this->getArticleID(),
4349                                 'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4350                                 'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4351                         ),
4352                         __METHOD__
4353                 );
4354         }
4355
4356         /**
4357          * Get the number of authors between the given revisions or revision IDs.
4358          * Used for diffs and other things that really need it.
4359          *
4360          * @param int|Revision $old Old revision or rev ID (first before range by default)
4361          * @param int|Revision $new New revision or rev ID (first after range by default)
4362          * @param int $limit Maximum number of authors
4363          * @param string|array $options (Optional): Single option, or an array of options:
4364          *     'include_old' Include $old in the range; $new is excluded.
4365          *     'include_new' Include $new in the range; $old is excluded.
4366          *     'include_both' Include both $old and $new in the range.
4367          *     Unknown option values are ignored.
4368          * @return int Number of revision authors in the range; zero if not both revisions exist
4369          */
4370         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4371                 if ( !( $old instanceof Revision ) ) {
4372                         $old = Revision::newFromTitle( $this, (int)$old );
4373                 }
4374                 if ( !( $new instanceof Revision ) ) {
4375                         $new = Revision::newFromTitle( $this, (int)$new );
4376                 }
4377                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4378                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4379                 // in the sanity check below?
4380                 if ( !$old || !$new ) {
4381                         return 0; // nothing to compare
4382                 }
4383                 $old_cmp = '>';
4384                 $new_cmp = '<';
4385                 $options = (array)$options;
4386                 if ( in_array( 'include_old', $options ) ) {
4387                         $old_cmp = '>=';
4388                 }
4389                 if ( in_array( 'include_new', $options ) ) {
4390                         $new_cmp = '<=';
4391                 }
4392                 if ( in_array( 'include_both', $options ) ) {
4393                         $old_cmp = '>=';
4394                         $new_cmp = '<=';
4395                 }
4396                 // No DB query needed if $old and $new are the same or successive revisions:
4397                 if ( $old->getId() === $new->getId() ) {
4398                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4399                 } elseif ( $old->getId() === $new->getParentId() ) {
4400                         if ( $old_cmp === '>' || $new_cmp === '<' ) {
4401                                 return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4402                         }
4403                         return ( $old->getRawUserText() === $new->getRawUserText() ) ? 1 : 2;
4404                 }
4405                 $dbr = wfGetDB( DB_SLAVE );
4406                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4407                         array(
4408                                 'rev_page' => $this->getArticleID(),
4409                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4410                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4411                         ), __METHOD__,
4412                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4413                 );
4414                 return (int)$dbr->numRows( $res );
4415         }
4416
4417         /**
4418          * Compare with another title.
4419          *
4420          * @param $title Title
4421          * @return Bool
4422          */
4423         public function equals( Title $title ) {
4424                 // Note: === is necessary for proper matching of number-like titles.
4425                 return $this->getInterwiki() === $title->getInterwiki()
4426                         && $this->getNamespace() == $title->getNamespace()
4427                         && $this->getDBkey() === $title->getDBkey();
4428         }
4429
4430         /**
4431          * Check if this title is a subpage of another title
4432          *
4433          * @param $title Title
4434          * @return Bool
4435          */
4436         public function isSubpageOf( Title $title ) {
4437                 return $this->getInterwiki() === $title->getInterwiki()
4438                         && $this->getNamespace() == $title->getNamespace()
4439                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4440         }
4441
4442         /**
4443          * Check if page exists.  For historical reasons, this function simply
4444          * checks for the existence of the title in the page table, and will
4445          * thus return false for interwiki links, special pages and the like.
4446          * If you want to know if a title can be meaningfully viewed, you should
4447          * probably call the isKnown() method instead.
4448          *
4449          * @return Bool
4450          */
4451         public function exists() {
4452                 return $this->getArticleID() != 0;
4453         }
4454
4455         /**
4456          * Should links to this title be shown as potentially viewable (i.e. as
4457          * "bluelinks"), even if there's no record by this title in the page
4458          * table?
4459          *
4460          * This function is semi-deprecated for public use, as well as somewhat
4461          * misleadingly named.  You probably just want to call isKnown(), which
4462          * calls this function internally.
4463          *
4464          * (ISSUE: Most of these checks are cheap, but the file existence check
4465          * can potentially be quite expensive.  Including it here fixes a lot of
4466          * existing code, but we might want to add an optional parameter to skip
4467          * it and any other expensive checks.)
4468          *
4469          * @return Bool
4470          */
4471         public function isAlwaysKnown() {
4472                 $isKnown = null;
4473
4474                 /**
4475                  * Allows overriding default behavior for determining if a page exists.
4476                  * If $isKnown is kept as null, regular checks happen. If it's
4477                  * a boolean, this value is returned by the isKnown method.
4478                  *
4479                  * @since 1.20
4480                  *
4481                  * @param Title $title
4482                  * @param boolean|null $isKnown
4483                  */
4484                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4485
4486                 if ( !is_null( $isKnown ) ) {
4487                         return $isKnown;
4488                 }
4489
4490                 if ( $this->mInterwiki != '' ) {
4491                         return true;  // any interwiki link might be viewable, for all we know
4492                 }
4493
4494                 switch ( $this->mNamespace ) {
4495                         case NS_MEDIA:
4496                         case NS_FILE:
4497                                 // file exists, possibly in a foreign repo
4498                                 return (bool)wfFindFile( $this );
4499                         case NS_SPECIAL:
4500                                 // valid special page
4501                                 return SpecialPageFactory::exists( $this->getDBkey() );
4502                         case NS_MAIN:
4503                                 // selflink, possibly with fragment
4504                                 return $this->mDbkeyform == '';
4505                         case NS_MEDIAWIKI:
4506                                 // known system message
4507                                 return $this->hasSourceText() !== false;
4508                         default:
4509                                 return false;
4510                 }
4511         }
4512
4513         /**
4514          * Does this title refer to a page that can (or might) be meaningfully
4515          * viewed?  In particular, this function may be used to determine if
4516          * links to the title should be rendered as "bluelinks" (as opposed to
4517          * "redlinks" to non-existent pages).
4518          * Adding something else to this function will cause inconsistency
4519          * since LinkHolderArray calls isAlwaysKnown() and does its own
4520          * page existence check.
4521          *
4522          * @return Bool
4523          */
4524         public function isKnown() {
4525                 return $this->isAlwaysKnown() || $this->exists();
4526         }
4527
4528         /**
4529          * Does this page have source text?
4530          *
4531          * @return Boolean
4532          */
4533         public function hasSourceText() {
4534                 if ( $this->exists() ) {
4535                         return true;
4536                 }
4537
4538                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4539                         // If the page doesn't exist but is a known system message, default
4540                         // message content will be displayed, same for language subpages-
4541                         // Use always content language to avoid loading hundreds of languages
4542                         // to get the link color.
4543                         global $wgContLang;
4544                         list( $name, ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4545                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4546                         return $message->exists();
4547                 }
4548
4549                 return false;
4550         }
4551
4552         /**
4553          * Get the default message text or false if the message doesn't exist
4554          *
4555          * @return String or false
4556          */
4557         public function getDefaultMessageText() {
4558                 global $wgContLang;
4559
4560                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4561                         return false;
4562                 }
4563
4564                 list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4565                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4566
4567                 if ( $message->exists() ) {
4568                         return $message->plain();
4569                 } else {
4570                         return false;
4571                 }
4572         }
4573
4574         /**
4575          * Updates page_touched for this page; called from LinksUpdate.php
4576          *
4577          * @return Bool true if the update succeeded
4578          */
4579         public function invalidateCache() {
4580                 if ( wfReadOnly() ) {
4581                         return false;
4582                 }
4583
4584                 $method = __METHOD__;
4585                 $dbw = wfGetDB( DB_MASTER );
4586                 $conds = $this->pageCond();
4587                 $dbw->onTransactionIdle( function() use ( $dbw, $conds, $method ) {
4588                         $dbw->update(
4589                                 'page',
4590                                 array( 'page_touched' => $dbw->timestamp() ),
4591                                 $conds,
4592                                 $method
4593                         );
4594                 } );
4595
4596                 return true;
4597         }
4598
4599         /**
4600          * Update page_touched timestamps and send squid purge messages for
4601          * pages linking to this title. May be sent to the job queue depending
4602          * on the number of links. Typically called on create and delete.
4603          */
4604         public function touchLinks() {
4605                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4606                 $u->doUpdate();
4607
4608                 if ( $this->getNamespace() == NS_CATEGORY ) {
4609                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4610                         $u->doUpdate();
4611                 }
4612         }
4613
4614         /**
4615          * Get the last touched timestamp
4616          *
4617          * @param $db DatabaseBase: optional db
4618          * @return String last-touched timestamp
4619          */
4620         public function getTouched( $db = null ) {
4621                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
4622                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4623                 return $touched;
4624         }
4625
4626         /**
4627          * Get the timestamp when this page was updated since the user last saw it.
4628          *
4629          * @param $user User
4630          * @return String|Null
4631          */
4632         public function getNotificationTimestamp( $user = null ) {
4633                 global $wgUser, $wgShowUpdatedMarker;
4634                 // Assume current user if none given
4635                 if ( !$user ) {
4636                         $user = $wgUser;
4637                 }
4638                 // Check cache first
4639                 $uid = $user->getId();
4640                 // avoid isset here, as it'll return false for null entries
4641                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4642                         return $this->mNotificationTimestamp[$uid];
4643                 }
4644                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4645                         return $this->mNotificationTimestamp[$uid] = false;
4646                 }
4647                 // Don't cache too much!
4648                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4649                         $this->mNotificationTimestamp = array();
4650                 }
4651                 $dbr = wfGetDB( DB_SLAVE );
4652                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4653                         'wl_notificationtimestamp',
4654                         array(
4655                                 'wl_user' => $user->getId(),
4656                                 'wl_namespace' => $this->getNamespace(),
4657                                 'wl_title' => $this->getDBkey(),
4658                         ),
4659                         __METHOD__
4660                 );
4661                 return $this->mNotificationTimestamp[$uid];
4662         }
4663
4664         /**
4665          * Generate strings used for xml 'id' names in monobook tabs
4666          *
4667          * @param string $prepend defaults to 'nstab-'
4668          * @return String XML 'id' name
4669          */
4670         public function getNamespaceKey( $prepend = 'nstab-' ) {
4671                 global $wgContLang;
4672                 // Gets the subject namespace if this title
4673                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4674                 // Checks if canonical namespace name exists for namespace
4675                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4676                         // Uses canonical namespace name
4677                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4678                 } else {
4679                         // Uses text of namespace
4680                         $namespaceKey = $this->getSubjectNsText();
4681                 }
4682                 // Makes namespace key lowercase
4683                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4684                 // Uses main
4685                 if ( $namespaceKey == '' ) {
4686                         $namespaceKey = 'main';
4687                 }
4688                 // Changes file to image for backwards compatibility
4689                 if ( $namespaceKey == 'file' ) {
4690                         $namespaceKey = 'image';
4691                 }
4692                 return $prepend . $namespaceKey;
4693         }
4694
4695         /**
4696          * Get all extant redirects to this Title
4697          *
4698          * @param int|Null $ns Single namespace to consider; NULL to consider all namespaces
4699          * @return Array of Title redirects to this title
4700          */
4701         public function getRedirectsHere( $ns = null ) {
4702                 $redirs = array();
4703
4704                 $dbr = wfGetDB( DB_SLAVE );
4705                 $where = array(
4706                         'rd_namespace' => $this->getNamespace(),
4707                         'rd_title' => $this->getDBkey(),
4708                         'rd_from = page_id'
4709                 );
4710                 if ( $this->isExternal() ) {
4711                         $where['rd_interwiki'] = $this->getInterwiki();
4712                 } else {
4713                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4714                 }
4715                 if ( !is_null( $ns ) ) {
4716                         $where['page_namespace'] = $ns;
4717                 }
4718
4719                 $res = $dbr->select(
4720                         array( 'redirect', 'page' ),
4721                         array( 'page_namespace', 'page_title' ),
4722                         $where,
4723                         __METHOD__
4724                 );
4725
4726                 foreach ( $res as $row ) {
4727                         $redirs[] = self::newFromRow( $row );
4728                 }
4729                 return $redirs;
4730         }
4731
4732         /**
4733          * Check if this Title is a valid redirect target
4734          *
4735          * @return Bool
4736          */
4737         public function isValidRedirectTarget() {
4738                 global $wgInvalidRedirectTargets;
4739
4740                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4741                 if ( $this->isSpecial( 'Userlogout' ) ) {
4742                         return false;
4743                 }
4744
4745                 foreach ( $wgInvalidRedirectTargets as $target ) {
4746                         if ( $this->isSpecial( $target ) ) {
4747                                 return false;
4748                         }
4749                 }
4750
4751                 return true;
4752         }
4753
4754         /**
4755          * Get a backlink cache object
4756          *
4757          * @return BacklinkCache
4758          */
4759         public function getBacklinkCache() {
4760                 return BacklinkCache::get( $this );
4761         }
4762
4763         /**
4764          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4765          *
4766          * @return Boolean
4767          */
4768         public function canUseNoindex() {
4769                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4770
4771                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4772                         ? $wgContentNamespaces
4773                         : $wgExemptFromUserRobotsControl;
4774
4775                 return !in_array( $this->mNamespace, $bannedNamespaces );
4776
4777         }
4778
4779         /**
4780          * Returns the raw sort key to be used for categories, with the specified
4781          * prefix.  This will be fed to Collation::getSortKey() to get a
4782          * binary sortkey that can be used for actual sorting.
4783          *
4784          * @param string $prefix The prefix to be used, specified using
4785          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4786          *   prefix.
4787          * @return string
4788          */
4789         public function getCategorySortkey( $prefix = '' ) {
4790                 $unprefixed = $this->getText();
4791
4792                 // Anything that uses this hook should only depend
4793                 // on the Title object passed in, and should probably
4794                 // tell the users to run updateCollations.php --force
4795                 // in order to re-sort existing category relations.
4796                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4797                 if ( $prefix !== '' ) {
4798                         # Separate with a line feed, so the unprefixed part is only used as
4799                         # a tiebreaker when two pages have the exact same prefix.
4800                         # In UCA, tab is the only character that can sort above LF
4801                         # so we strip both of them from the original prefix.
4802                         $prefix = strtr( $prefix, "\n\t", '  ' );
4803                         return "$prefix\n$unprefixed";
4804                 }
4805                 return $unprefixed;
4806         }
4807
4808         /**
4809          * Get the language in which the content of this page is written in
4810          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4811          * e.g. $wgLang (such as special pages, which are in the user language).
4812          *
4813          * @since 1.18
4814          * @return Language
4815          */
4816         public function getPageLanguage() {
4817                 global $wgLang, $wgLanguageCode;
4818                 wfProfileIn( __METHOD__ );
4819                 if ( $this->isSpecialPage() ) {
4820                         // special pages are in the user language
4821                         wfProfileOut( __METHOD__ );
4822                         return $wgLang;
4823                 }
4824
4825                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4826                         // Note that this may depend on user settings, so the cache should be only per-request.
4827                         // NOTE: ContentHandler::getPageLanguage() may need to load the content to determine the page language!
4828                         // Checking $wgLanguageCode hasn't changed for the benefit of unit tests.
4829                         $contentHandler = ContentHandler::getForTitle( $this );
4830                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4831                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4832                 } else {
4833                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4834                 }
4835                 wfProfileOut( __METHOD__ );
4836                 return $langObj;
4837         }
4838
4839         /**
4840          * Get the language in which the content of this page is written when
4841          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4842          * e.g. $wgLang (such as special pages, which are in the user language).
4843          *
4844          * @since 1.20
4845          * @return Language
4846          */
4847         public function getPageViewLanguage() {
4848                 global $wgLang;
4849
4850                 if ( $this->isSpecialPage() ) {
4851                         // If the user chooses a variant, the content is actually
4852                         // in a language whose code is the variant code.
4853                         $variant = $wgLang->getPreferredVariant();
4854                         if ( $wgLang->getCode() !== $variant ) {
4855                                 return Language::factory( $variant );
4856                         }
4857
4858                         return $wgLang;
4859                 }
4860
4861                 //NOTE: can't be cached persistently, depends on user settings
4862                 //NOTE: ContentHandler::getPageViewLanguage() may need to load the content to determine the page language!
4863                 $contentHandler = ContentHandler::getForTitle( $this );
4864                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4865                 return $pageLang;
4866         }
4867
4868         /**
4869          * Get a list of rendered edit notices for this page.
4870          *
4871          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4872          * they will already be wrapped in paragraphs.
4873          *
4874          * @since 1.21
4875          * @param int oldid Revision ID that's being edited
4876          * @return Array
4877          */
4878         public function getEditNotices( $oldid = 0 ) {
4879                 $notices = array();
4880
4881                 # Optional notices on a per-namespace and per-page basis
4882                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4883                 $editnotice_ns_message = wfMessage( $editnotice_ns );
4884                 if ( $editnotice_ns_message->exists() ) {
4885                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
4886                 }
4887                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4888                         $parts = explode( '/', $this->getDBkey() );
4889                         $editnotice_base = $editnotice_ns;
4890                         while ( count( $parts ) > 0 ) {
4891                                 $editnotice_base .= '-' . array_shift( $parts );
4892                                 $editnotice_base_msg = wfMessage( $editnotice_base );
4893                                 if ( $editnotice_base_msg->exists() ) {
4894                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
4895                                 }
4896                         }
4897                 } else {
4898                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
4899                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
4900                         $editnoticeMsg = wfMessage( $editnoticeText );
4901                         if ( $editnoticeMsg->exists() ) {
4902                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
4903                         }
4904                 }
4905
4906                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4907                 return $notices;
4908         }
4909 }