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         # Zero except in {{transclusion}} tags
  83         var $mDefaultNamespace = NS_MAIN; // /< Namespace index when there is no namespace
  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                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 773                         return $this->mUserCaseDBKey;
 774                 } else {
 775                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 776                         return $this->mDbkeyform;
 777                 }
 778         }
 779
 780         /**
 781          * Get the namespace index, i.e. one of the NS_xxxx constants.
 782          *
 783          * @return Integer: Namespace index
 784          */
 785         public function getNamespace() {
 786                 return $this->mNamespace;
 787         }
 788
 789         /**
 790          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 791          *
 792          * @throws MWException
 793          * @return String: Content model id
 794          */
 795         public function getContentModel() {
 796                 if ( !$this->mContentModel ) {
 797                         $linkCache = LinkCache::singleton();
 798                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 799                 }
 800
 801                 if ( !$this->mContentModel ) {
 802                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 803                 }
 804
 805                 if ( !$this->mContentModel ) {
 806                         throw new MWException( 'Failed to determine content model!' );
 807                 }
 808
 809                 return $this->mContentModel;
 810         }
 811
 812         /**
 813          * Convenience method for checking a title's content model name
 814          *
 815          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 816          * @return Boolean true if $this->getContentModel() == $id
 817          */
 818         public function hasContentModel( $id ) {
 819                 return $this->getContentModel() == $id;
 820         }
 821
 822         /**
 823          * Get the namespace text
 824          *
 825          * @return String: Namespace text
 826          */
 827         public function getNsText() {
 828                 global $wgContLang;
 829
 830                 if ( $this->mInterwiki != '' ) {
 831                         // This probably shouldn't even happen. ohh man, oh yuck.
 832                         // But for interwiki transclusion it sometimes does.
 833                         // Shit. Shit shit shit.
 834                         //
 835                         // Use the canonical namespaces if possible to try to
 836                         // resolve a foreign namespace.
 837                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 838                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 839                         }
 840                 }
 841
 842                 if ( $wgContLang->needsGenderDistinction() &&
 843                                 MWNamespace::hasGenderDistinction( $this->mNamespace ) ) {
 844                         $gender = GenderCache::singleton()->getGenderOf( $this->getText(), __METHOD__ );
 845                         return $wgContLang->getGenderNsText( $this->mNamespace, $gender );
 846                 }
 847
 848                 return $wgContLang->getNsText( $this->mNamespace );
 849         }
 850
 851         /**
 852          * Get the namespace text of the subject (rather than talk) page
 853          *
 854          * @return String Namespace text
 855          */
 856         public function getSubjectNsText() {
 857                 global $wgContLang;
 858                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 859         }
 860
 861         /**
 862          * Get the namespace text of the talk page
 863          *
 864          * @return String Namespace text
 865          */
 866         public function getTalkNsText() {
 867                 global $wgContLang;
 868                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
 869         }
 870
 871         /**
 872          * Could this title have a corresponding talk page?
 873          *
 874          * @return Bool TRUE or FALSE
 875          */
 876         public function canTalk() {
 877                 return MWNamespace::canTalk( $this->mNamespace );
 878         }
 879
 880         /**
 881          * Is this in a namespace that allows actual pages?
 882          *
 883          * @return Bool
 884          * @internal note -- uses hardcoded namespace index instead of constants
 885          */
 886         public function canExist() {
 887                 return $this->mNamespace >= NS_MAIN;
 888         }
 889
 890         /**
 891          * Can this title be added to a user's watchlist?
 892          *
 893          * @return Bool TRUE or FALSE
 894          */
 895         public function isWatchable() {
 896                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
 897         }
 898
 899         /**
 900          * Returns true if this is a special page.
 901          *
 902          * @return boolean
 903          */
 904         public function isSpecialPage() {
 905                 return $this->getNamespace() == NS_SPECIAL;
 906         }
 907
 908         /**
 909          * Returns true if this title resolves to the named special page
 910          *
 911          * @param string $name The special page name
 912          * @return boolean
 913          */
 914         public function isSpecial( $name ) {
 915                 if ( $this->isSpecialPage() ) {
 916                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
 917                         if ( $name == $thisName ) {
 918                                 return true;
 919                         }
 920                 }
 921                 return false;
 922         }
 923
 924         /**
 925          * If the Title refers to a special page alias which is not the local default, resolve
 926          * the alias, and localise the name as necessary.  Otherwise, return $this
 927          *
 928          * @return Title
 929          */
 930         public function fixSpecialName() {
 931                 if ( $this->isSpecialPage() ) {
 932                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
 933                         if ( $canonicalName ) {
 934                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
 935                                 if ( $localName != $this->mDbkeyform ) {
 936                                         return Title::makeTitle( NS_SPECIAL, $localName );
 937                                 }
 938                         }
 939                 }
 940                 return $this;
 941         }
 942
 943         /**
 944          * Returns true if the title is inside the specified namespace.
 945          *
 946          * Please make use of this instead of comparing to getNamespace()
 947          * This function is much more resistant to changes we may make
 948          * to namespaces than code that makes direct comparisons.
 949          * @param int $ns The namespace
 950          * @return bool
 951          * @since 1.19
 952          */
 953         public function inNamespace( $ns ) {
 954                 return MWNamespace::equals( $this->getNamespace(), $ns );
 955         }
 956
 957         /**
 958          * Returns true if the title is inside one of the specified namespaces.
 959          *
 960          * @param ...$namespaces The namespaces to check for
 961          * @return bool
 962          * @since 1.19
 963          */
 964         public function inNamespaces( /* ... */ ) {
 965                 $namespaces = func_get_args();
 966                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
 967                         $namespaces = $namespaces[0];
 968                 }
 969
 970                 foreach ( $namespaces as $ns ) {
 971                         if ( $this->inNamespace( $ns ) ) {
 972                                 return true;
 973                         }
 974                 }
 975
 976                 return false;
 977         }
 978
 979         /**
 980          * Returns true if the title has the same subject namespace as the
 981          * namespace specified.
 982          * For example this method will take NS_USER and return true if namespace
 983          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
 984          * as their subject namespace.
 985          *
 986          * This is MUCH simpler than individually testing for equivalence
 987          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
 988          * @since 1.19
 989          * @param $ns int
 990          * @return bool
 991          */
 992         public function hasSubjectNamespace( $ns ) {
 993                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
 994         }
 995
 996         /**
 997          * Is this Title in a namespace which contains content?
 998          * In other words, is this a content page, for the purposes of calculating
 999          * statistics, etc?
1000          *
1001          * @return Boolean
1002          */
1003         public function isContentPage() {
1004                 return MWNamespace::isContent( $this->getNamespace() );
1005         }
1006
1007         /**
1008          * Would anybody with sufficient privileges be able to move this page?
1009          * Some pages just aren't movable.
1010          *
1011          * @return Bool TRUE or FALSE
1012          */
1013         public function isMovable() {
1014                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->getInterwiki() != '' ) {
1015                         // Interwiki title or immovable namespace. Hooks don't get to override here
1016                         return false;
1017                 }
1018
1019                 $result = true;
1020                 wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
1021                 return $result;
1022         }
1023
1024         /**
1025          * Is this the mainpage?
1026          * @note Title::newFromText seems to be sufficiently optimized by the title
1027          * cache that we don't need to over-optimize by doing direct comparisons and
1028          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1029          * ends up reporting something differently than $title->isMainPage();
1030          *
1031          * @since 1.18
1032          * @return Bool
1033          */
1034         public function isMainPage() {
1035                 return $this->equals( Title::newMainPage() );
1036         }
1037
1038         /**
1039          * Is this a subpage?
1040          *
1041          * @return Bool
1042          */
1043         public function isSubpage() {
1044                 return MWNamespace::hasSubpages( $this->mNamespace )
1045                         ? strpos( $this->getText(), '/' ) !== false
1046                         : false;
1047         }
1048
1049         /**
1050          * Is this a conversion table for the LanguageConverter?
1051          *
1052          * @return Bool
1053          */
1054         public function isConversionTable() {
1055                 // @todo ConversionTable should become a separate content model.
1056
1057                 return $this->getNamespace() == NS_MEDIAWIKI &&
1058                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1059         }
1060
1061         /**
1062          * Does that page contain wikitext, or it is JS, CSS or whatever?
1063          *
1064          * @return Bool
1065          */
1066         public function isWikitextPage() {
1067                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1068         }
1069
1070         /**
1071          * Could this page contain custom CSS or JavaScript for the global UI.
1072          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1073          * or CONTENT_MODEL_JAVASCRIPT.
1074          *
1075          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage() for that!
1076          *
1077          * Note that this method should not return true for pages that contain and show "inactive" CSS or JS.
1078          *
1079          * @return Bool
1080          */
1081         public function isCssOrJsPage() {
1082                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1083                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1084                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1085
1086                 #NOTE: this hook is also called in ContentHandler::getDefaultModel. It's called here again to make sure
1087                 #      hook functions can force this method to return true even outside the mediawiki namespace.
1088
1089                 wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ) );
1090
1091                 return $isCssOrJsPage;
1092         }
1093
1094         /**
1095          * Is this a .css or .js subpage of a user page?
1096          * @return Bool
1097          */
1098         public function isCssJsSubpage() {
1099                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1100                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1101                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1102         }
1103
1104         /**
1105          * Trim down a .css or .js subpage title to get the corresponding skin name
1106          *
1107          * @return string containing skin name from .css or .js subpage title
1108          */
1109         public function getSkinFromCssJsSubpage() {
1110                 $subpage = explode( '/', $this->mTextform );
1111                 $subpage = $subpage[count( $subpage ) - 1];
1112                 $lastdot = strrpos( $subpage, '.' );
1113                 if ( $lastdot === false ) {
1114                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1115                 }
1116                 return substr( $subpage, 0, $lastdot );
1117         }
1118
1119         /**
1120          * Is this a .css subpage of a user page?
1121          *
1122          * @return Bool
1123          */
1124         public function isCssSubpage() {
1125                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1126                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1127         }
1128
1129         /**
1130          * Is this a .js subpage of a user page?
1131          *
1132          * @return Bool
1133          */
1134         public function isJsSubpage() {
1135                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1136                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1137         }
1138
1139         /**
1140          * Is this a talk page of some sort?
1141          *
1142          * @return Bool
1143          */
1144         public function isTalkPage() {
1145                 return MWNamespace::isTalk( $this->getNamespace() );
1146         }
1147
1148         /**
1149          * Get a Title object associated with the talk page of this article
1150          *
1151          * @return Title the object for the talk page
1152          */
1153         public function getTalkPage() {
1154                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1155         }
1156
1157         /**
1158          * Get a title object associated with the subject page of this
1159          * talk page
1160          *
1161          * @return Title the object for the subject page
1162          */
1163         public function getSubjectPage() {
1164                 // Is this the same title?
1165                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1166                 if ( $this->getNamespace() == $subjectNS ) {
1167                         return $this;
1168                 }
1169                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1170         }
1171
1172         /**
1173          * Get the default namespace index, for when there is no namespace
1174          *
1175          * @return Int Default namespace index
1176          */
1177         public function getDefaultNamespace() {
1178                 return $this->mDefaultNamespace;
1179         }
1180
1181         /**
1182          * Get title for search index
1183          *
1184          * @return String a stripped-down title string ready for the
1185          *  search index
1186          */
1187         public function getIndexTitle() {
1188                 return Title::indexTitle( $this->mNamespace, $this->mTextform );
1189         }
1190
1191         /**
1192          * Get the Title fragment (i.e.\ the bit after the #) in text form
1193          *
1194          * @return String Title fragment
1195          */
1196         public function getFragment() {
1197                 return $this->mFragment;
1198         }
1199
1200         /**
1201          * Get the fragment in URL form, including the "#" character if there is one
1202          * @return String Fragment in URL form
1203          */
1204         public function getFragmentForURL() {
1205                 if ( $this->mFragment == '' ) {
1206                         return '';
1207                 } else {
1208                         return '#' . Title::escapeFragmentForURL( $this->mFragment );
1209                 }
1210         }
1211
1212         /**
1213          * Set the fragment for this title. Removes the first character from the
1214          * specified fragment before setting, so it assumes you're passing it with
1215          * an initial "#".
1216          *
1217          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1218          * Still in active use privately.
1219          *
1220          * @param string $fragment text
1221          */
1222         public function setFragment( $fragment ) {
1223                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1224         }
1225
1226         /**
1227          * Prefix some arbitrary text with the namespace or interwiki prefix
1228          * of this object
1229          *
1230          * @param string $name the text
1231          * @return String the prefixed text
1232          * @private
1233          */
1234         private function prefix( $name ) {
1235                 $p = '';
1236                 if ( $this->mInterwiki != '' ) {
1237                         $p = $this->mInterwiki . ':';
1238                 }
1239
1240                 if ( 0 != $this->mNamespace ) {
1241                         $p .= $this->getNsText() . ':';
1242                 }
1243                 return $p . $name;
1244         }
1245
1246         /**
1247          * Get the prefixed database key form
1248          *
1249          * @return String the prefixed title, with underscores and
1250          *  any interwiki and namespace prefixes
1251          */
1252         public function getPrefixedDBkey() {
1253                 $s = $this->prefix( $this->mDbkeyform );
1254                 $s = str_replace( ' ', '_', $s );
1255                 return $s;
1256         }
1257
1258         /**
1259          * Get the prefixed title with spaces.
1260          * This is the form usually used for display
1261          *
1262          * @return String the prefixed title, with spaces
1263          */
1264         public function getPrefixedText() {
1265                 // @todo FIXME: Bad usage of empty() ?
1266                 if ( empty( $this->mPrefixedText ) ) {
1267                         $s = $this->prefix( $this->mTextform );
1268                         $s = str_replace( '_', ' ', $s );
1269                         $this->mPrefixedText = $s;
1270                 }
1271                 return $this->mPrefixedText;
1272         }
1273
1274         /**
1275          * Return a string representation of this title
1276          *
1277          * @return String representation of this title
1278          */
1279         public function __toString() {
1280                 return $this->getPrefixedText();
1281         }
1282
1283         /**
1284          * Get the prefixed title with spaces, plus any fragment
1285          * (part beginning with '#')
1286          *
1287          * @return String the prefixed title, with spaces and the fragment, including '#'
1288          */
1289         public function getFullText() {
1290                 $text = $this->getPrefixedText();
1291                 if ( $this->mFragment != '' ) {
1292                         $text .= '#' . $this->mFragment;
1293                 }
1294                 return $text;
1295         }
1296
1297         /**
1298          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1299          *
1300          * @par Example:
1301          * @code
1302          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1303          * # returns: 'Foo'
1304          * @endcode
1305          *
1306          * @return String Root name
1307          * @since 1.20
1308          */
1309         public function getRootText() {
1310                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1311                         return $this->getText();
1312                 }
1313
1314                 return strtok( $this->getText(), '/' );
1315         }
1316
1317         /**
1318          * Get the root page name title, i.e. the leftmost part before any slashes
1319          *
1320          * @par Example:
1321          * @code
1322          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1323          * # returns: Title{User:Foo}
1324          * @endcode
1325          *
1326          * @return Title Root title
1327          * @since 1.20
1328          */
1329         public function getRootTitle() {
1330                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1331         }
1332
1333         /**
1334          * Get the base page name without a namespace, i.e. the part before the subpage name
1335          *
1336          * @par Example:
1337          * @code
1338          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1339          * # returns: 'Foo/Bar'
1340          * @endcode
1341          *
1342          * @return String Base name
1343          */
1344         public function getBaseText() {
1345                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1346                         return $this->getText();
1347                 }
1348
1349                 $parts = explode( '/', $this->getText() );
1350                 # Don't discard the real title if there's no subpage involved
1351                 if ( count( $parts ) > 1 ) {
1352                         unset( $parts[count( $parts ) - 1] );
1353                 }
1354                 return implode( '/', $parts );
1355         }
1356
1357         /**
1358          * Get the base page name title, i.e. the part before the subpage name
1359          *
1360          * @par Example:
1361          * @code
1362          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1363          * # returns: Title{User:Foo/Bar}
1364          * @endcode
1365          *
1366          * @return Title Base title
1367          * @since 1.20
1368          */
1369         public function getBaseTitle() {
1370                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1371         }
1372
1373         /**
1374          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1375          *
1376          * @par Example:
1377          * @code
1378          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1379          * # returns: "Baz"
1380          * @endcode
1381          *
1382          * @return String Subpage name
1383          */
1384         public function getSubpageText() {
1385                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1386                         return $this->mTextform;
1387                 }
1388                 $parts = explode( '/', $this->mTextform );
1389                 return $parts[count( $parts ) - 1];
1390         }
1391
1392         /**
1393          * Get the title for a subpage of the current page
1394          *
1395          * @par Example:
1396          * @code
1397          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1398          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1399          * @endcode
1400          *
1401          * @param string $text The subpage name to add to the title
1402          * @return Title Subpage title
1403          * @since 1.20
1404          */
1405         public function getSubpage( $text ) {
1406                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1407         }
1408
1409         /**
1410          * Get the HTML-escaped displayable text form.
1411          * Used for the title field in <a> tags.
1412          *
1413          * @return String the text, including any prefixes
1414          * @deprecated since 1.19
1415          */
1416         public function getEscapedText() {
1417                 wfDeprecated( __METHOD__, '1.19' );
1418                 return htmlspecialchars( $this->getPrefixedText() );
1419         }
1420
1421         /**
1422          * Get a URL-encoded form of the subpage text
1423          *
1424          * @return String URL-encoded subpage name
1425          */
1426         public function getSubpageUrlForm() {
1427                 $text = $this->getSubpageText();
1428                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1429                 return $text;
1430         }
1431
1432         /**
1433          * Get a URL-encoded title (not an actual URL) including interwiki
1434          *
1435          * @return String the URL-encoded form
1436          */
1437         public function getPrefixedURL() {
1438                 $s = $this->prefix( $this->mDbkeyform );
1439                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1440                 return $s;
1441         }
1442
1443         /**
1444          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1445          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1446          * second argument named variant. This was deprecated in favor
1447          * of passing an array of option with a "variant" key
1448          * Once $query2 is removed for good, this helper can be dropped
1449          * and the wfArrayToCgi moved to getLocalURL();
1450          *
1451          * @since 1.19 (r105919)
1452          * @param $query
1453          * @param $query2 bool
1454          * @return String
1455          */
1456         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1457                 if ( $query2 !== false ) {
1458                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1459                                 "method called with a second parameter is deprecated. Add your " .
1460                                 "parameter to an array passed as the first parameter.", "1.19" );
1461                 }
1462                 if ( is_array( $query ) ) {
1463                         $query = wfArrayToCgi( $query );
1464                 }
1465                 if ( $query2 ) {
1466                         if ( is_string( $query2 ) ) {
1467                                 // $query2 is a string, we will consider this to be
1468                                 // a deprecated $variant argument and add it to the query
1469                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1470                         } else {
1471                                 $query2 = wfArrayToCgi( $query2 );
1472                         }
1473                         // If we have $query content add a & to it first
1474                         if ( $query ) {
1475                                 $query .= '&';
1476                         }
1477                         // Now append the queries together
1478                         $query .= $query2;
1479                 }
1480                 return $query;
1481         }
1482
1483         /**
1484          * Get a real URL referring to this title, with interwiki link and
1485          * fragment
1486          *
1487          * See getLocalURL for the arguments.
1488          *
1489          * @see self::getLocalURL
1490          * @see wfExpandUrl
1491          * @param $query
1492          * @param $query2 bool
1493          * @param $proto Protocol type to use in URL
1494          * @return String the URL
1495          */
1496         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1497                 $query = self::fixUrlQueryArgs( $query, $query2 );
1498
1499                 # Hand off all the decisions on urls to getLocalURL
1500                 $url = $this->getLocalURL( $query );
1501
1502                 # Expand the url to make it a full url. Note that getLocalURL has the
1503                 # potential to output full urls for a variety of reasons, so we use
1504                 # wfExpandUrl instead of simply prepending $wgServer
1505                 $url = wfExpandUrl( $url, $proto );
1506
1507                 # Finally, add the fragment.
1508                 $url .= $this->getFragmentForURL();
1509
1510                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1511                 return $url;
1512         }
1513
1514         /**
1515          * Get a URL with no fragment or server name.  If this page is generated
1516          * with action=render, $wgServer is prepended.
1517          *
1518          * @param string|array $query an optional query string,
1519          *   not used for interwiki links. Can be specified as an associative array as well,
1520          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1521          *   Some query patterns will trigger various shorturl path replacements.
1522          * @param $query2 Mixed: An optional secondary query array. This one MUST
1523          *   be an array. If a string is passed it will be interpreted as a deprecated
1524          *   variant argument and urlencoded into a variant= argument.
1525          *   This second query argument will be added to the $query
1526          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1527          *   pair in the first parameter array instead.
1528          *
1529          * @return String the URL
1530          */
1531         public function getLocalURL( $query = '', $query2 = false ) {
1532                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1533
1534                 $query = self::fixUrlQueryArgs( $query, $query2 );
1535
1536                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1537                 if ( $interwiki ) {
1538                         $namespace = $this->getNsText();
1539                         if ( $namespace != '' ) {
1540                                 # Can this actually happen? Interwikis shouldn't be parsed.
1541                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1542                                 $namespace .= ':';
1543                         }
1544                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1545                         $url = wfAppendQuery( $url, $query );
1546                 } else {
1547                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1548                         if ( $query == '' ) {
1549                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1550                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1551                         } else {
1552                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1553                                 $url = false;
1554                                 $matches = array();
1555
1556                                 if ( !empty( $wgActionPaths )
1557                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1558                                 ) {
1559                                         $action = urldecode( $matches[2] );
1560                                         if ( isset( $wgActionPaths[$action] ) ) {
1561                                                 $query = $matches[1];
1562                                                 if ( isset( $matches[4] ) ) {
1563                                                         $query .= $matches[4];
1564                                                 }
1565                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1566                                                 if ( $query != '' ) {
1567                                                         $url = wfAppendQuery( $url, $query );
1568                                                 }
1569                                         }
1570                                 }
1571
1572                                 if ( $url === false
1573                                         && $wgVariantArticlePath
1574                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1575                                         && $this->getPageLanguage()->hasVariants()
1576                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1577                                 ) {
1578                                         $variant = urldecode( $matches[1] );
1579                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1580                                                 // Only do the variant replacement if the given variant is a valid
1581                                                 // variant for the page's language.
1582                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1583                                                 $url = str_replace( '$1', $dbkey, $url );
1584                                         }
1585                                 }
1586
1587                                 if ( $url === false ) {
1588                                         if ( $query == '-' ) {
1589                                                 $query = '';
1590                                         }
1591                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1592                                 }
1593                         }
1594
1595                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1596
1597                         // @todo FIXME: This causes breakage in various places when we
1598                         // actually expected a local URL and end up with dupe prefixes.
1599                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1600                                 $url = $wgServer . $url;
1601                         }
1602                 }
1603                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1604                 return $url;
1605         }
1606
1607         /**
1608          * Get a URL that's the simplest URL that will be valid to link, locally,
1609          * to the current Title.  It includes the fragment, but does not include
1610          * the server unless action=render is used (or the link is external).  If
1611          * there's a fragment but the prefixed text is empty, we just return a link
1612          * to the fragment.
1613          *
1614          * The result obviously should not be URL-escaped, but does need to be
1615          * HTML-escaped if it's being output in HTML.
1616          *
1617          * See getLocalURL for the arguments.
1618          *
1619          * @param $query
1620          * @param $query2 bool
1621          * @param $proto Protocol to use; setting this will cause a full URL to be used
1622          * @see self::getLocalURL
1623          * @return String the URL
1624          */
1625         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1626                 wfProfileIn( __METHOD__ );
1627                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1628                         $ret = $this->getFullURL( $query, $query2, $proto );
1629                 } elseif ( $this->getPrefixedText() === '' && $this->getFragment() !== '' ) {
1630                         $ret = $this->getFragmentForURL();
1631                 } else {
1632                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1633                 }
1634                 wfProfileOut( __METHOD__ );
1635                 return $ret;
1636         }
1637
1638         /**
1639          * Get an HTML-escaped version of the URL form, suitable for
1640          * using in a link, without a server name or fragment
1641          *
1642          * See getLocalURL for the arguments.
1643          *
1644          * @see self::getLocalURL
1645          * @param $query string
1646          * @param $query2 bool|string
1647          * @return String the URL
1648          * @deprecated since 1.19
1649          */
1650         public function escapeLocalURL( $query = '', $query2 = false ) {
1651                 wfDeprecated( __METHOD__, '1.19' );
1652                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1653         }
1654
1655         /**
1656          * Get an HTML-escaped version of the URL form, suitable for
1657          * using in a link, including the server name and fragment
1658          *
1659          * See getLocalURL for the arguments.
1660          *
1661          * @see self::getLocalURL
1662          * @return String the URL
1663          * @deprecated since 1.19
1664          */
1665         public function escapeFullURL( $query = '', $query2 = false ) {
1666                 wfDeprecated( __METHOD__, '1.19' );
1667                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1668         }
1669
1670         /**
1671          * Get the URL form for an internal link.
1672          * - Used in various Squid-related code, in case we have a different
1673          * internal hostname for the server from the exposed one.
1674          *
1675          * This uses $wgInternalServer to qualify the path, or $wgServer
1676          * if $wgInternalServer is not set. If the server variable used is
1677          * protocol-relative, the URL will be expanded to http://
1678          *
1679          * See getLocalURL for the arguments.
1680          *
1681          * @see self::getLocalURL
1682          * @return String the URL
1683          */
1684         public function getInternalURL( $query = '', $query2 = false ) {
1685                 global $wgInternalServer, $wgServer;
1686                 $query = self::fixUrlQueryArgs( $query, $query2 );
1687                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1688                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1689                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1690                 return $url;
1691         }
1692
1693         /**
1694          * Get the URL for a canonical link, for use in things like IRC and
1695          * e-mail notifications. Uses $wgCanonicalServer and the
1696          * GetCanonicalURL hook.
1697          *
1698          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1699          *
1700          * See getLocalURL for the arguments.
1701          *
1702          * @see self::getLocalURL
1703          * @return string The URL
1704          * @since 1.18
1705          */
1706         public function getCanonicalURL( $query = '', $query2 = false ) {
1707                 $query = self::fixUrlQueryArgs( $query, $query2 );
1708                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1709                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1710                 return $url;
1711         }
1712
1713         /**
1714          * HTML-escaped version of getCanonicalURL()
1715          *
1716          * See getLocalURL for the arguments.
1717          *
1718          * @see self::getLocalURL
1719          * @since 1.18
1720          * @return string
1721          * @deprecated since 1.19
1722          */
1723         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1724                 wfDeprecated( __METHOD__, '1.19' );
1725                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1726         }
1727
1728         /**
1729          * Get the edit URL for this Title
1730          *
1731          * @return String the URL, or a null string if this is an
1732          *  interwiki link
1733          */
1734         public function getEditURL() {
1735                 if ( $this->mInterwiki != '' ) {
1736                         return '';
1737                 }
1738                 $s = $this->getLocalURL( 'action=edit' );
1739
1740                 return $s;
1741         }
1742
1743         /**
1744          * Is $wgUser watching this page?
1745          *
1746          * @deprecated in 1.20; use User::isWatched() instead.
1747          * @return Bool
1748          */
1749         public function userIsWatching() {
1750                 global $wgUser;
1751
1752                 if ( is_null( $this->mWatched ) ) {
1753                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1754                                 $this->mWatched = false;
1755                         } else {
1756                                 $this->mWatched = $wgUser->isWatched( $this );
1757                         }
1758                 }
1759                 return $this->mWatched;
1760         }
1761
1762         /**
1763          * Can $wgUser read this page?
1764          *
1765          * @deprecated in 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1766          * @return Bool
1767          * @todo fold these checks into userCan()
1768          */
1769         public function userCanRead() {
1770                 wfDeprecated( __METHOD__, '1.19' );
1771                 return $this->userCan( 'read' );
1772         }
1773
1774         /**
1775          * Can $user perform $action on this page?
1776          * This skips potentially expensive cascading permission checks
1777          * as well as avoids expensive error formatting
1778          *
1779          * Suitable for use for nonessential UI controls in common cases, but
1780          * _not_ for functional access control.
1781          *
1782          * May provide false positives, but should never provide a false negative.
1783          *
1784          * @param string $action action that permission needs to be checked for
1785          * @param $user User to check (since 1.19); $wgUser will be used if not
1786          *              provided.
1787          * @return Bool
1788          */
1789         public function quickUserCan( $action, $user = null ) {
1790                 return $this->userCan( $action, $user, false );
1791         }
1792
1793         /**
1794          * Can $user perform $action on this page?
1795          *
1796          * @param string $action action that permission needs to be checked for
1797          * @param $user User to check (since 1.19); $wgUser will be used if not
1798          *   provided.
1799          * @param bool $doExpensiveQueries Set this to false to avoid doing
1800          *   unnecessary queries.
1801          * @return Bool
1802          */
1803         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1804                 if ( !$user instanceof User ) {
1805                         global $wgUser;
1806                         $user = $wgUser;
1807                 }
1808                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries, true ) );
1809         }
1810
1811         /**
1812          * Can $user perform $action on this page?
1813          *
1814          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1815          *
1816          * @param string $action action that permission needs to be checked for
1817          * @param $user User to check
1818          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1819          *   queries by skipping checks for cascading protections and user blocks.
1820          * @param array $ignoreErrors of Strings Set this to a list of message keys
1821          *   whose corresponding errors may be ignored.
1822          * @return Array of arguments to wfMessage to explain permissions problems.
1823          */
1824         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
1825                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1826
1827                 // Remove the errors being ignored.
1828                 foreach ( $errors as $index => $error ) {
1829                         $error_key = is_array( $error ) ? $error[0] : $error;
1830
1831                         if ( in_array( $error_key, $ignoreErrors ) ) {
1832                                 unset( $errors[$index] );
1833                         }
1834                 }
1835
1836                 return $errors;
1837         }
1838
1839         /**
1840          * Permissions checks that fail most often, and which are easiest to test.
1841          *
1842          * @param string $action the action to check
1843          * @param $user User user to check
1844          * @param array $errors list of current errors
1845          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1846          * @param $short Boolean short circuit on first error
1847          *
1848          * @return Array list of errors
1849          */
1850         private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1851                 if ( !wfRunHooks( 'TitleQuickPermissions', array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) ) ) {
1852                         return $errors;
1853                 }
1854
1855                 if ( $action == 'create' ) {
1856                         if (
1857                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1858                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1859                         ) {
1860                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1861                         }
1862                 } elseif ( $action == 'move' ) {
1863                         if ( !$user->isAllowed( 'move-rootuserpages' )
1864                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1865                                 // Show user page-specific message only if the user can move other pages
1866                                 $errors[] = array( 'cant-move-user-page' );
1867                         }
1868
1869                         // Check if user is allowed to move files if it's a file
1870                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1871                                 $errors[] = array( 'movenotallowedfile' );
1872                         }
1873
1874                         if ( !$user->isAllowed( 'move' ) ) {
1875                                 // User can't move anything
1876                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1877                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1878                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1879                                         // custom message if logged-in users without any special rights can move
1880                                         $errors[] = array( 'movenologintext' );
1881                                 } else {
1882                                         $errors[] = array( 'movenotallowed' );
1883                                 }
1884                         }
1885                 } elseif ( $action == 'move-target' ) {
1886                         if ( !$user->isAllowed( 'move' ) ) {
1887                                 // User can't move anything
1888                                 $errors[] = array( 'movenotallowed' );
1889                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1890                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1891                                 // Show user page-specific message only if the user can move other pages
1892                                 $errors[] = array( 'cant-move-to-user-page' );
1893                         }
1894                 } elseif ( !$user->isAllowed( $action ) ) {
1895                         $errors[] = $this->missingPermissionError( $action, $short );
1896                 }
1897
1898                 return $errors;
1899         }
1900
1901         /**
1902          * Add the resulting error code to the errors array
1903          *
1904          * @param array $errors list of current errors
1905          * @param $result Mixed result of errors
1906          *
1907          * @return Array list of errors
1908          */
1909         private function resultToError( $errors, $result ) {
1910                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1911                         // A single array representing an error
1912                         $errors[] = $result;
1913                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
1914                         // A nested array representing multiple errors
1915                         $errors = array_merge( $errors, $result );
1916                 } elseif ( $result !== '' && is_string( $result ) ) {
1917                         // A string representing a message-id
1918                         $errors[] = array( $result );
1919                 } elseif ( $result === false ) {
1920                         // a generic "We don't want them to do that"
1921                         $errors[] = array( 'badaccess-group0' );
1922                 }
1923                 return $errors;
1924         }
1925
1926         /**
1927          * Check various permission hooks
1928          *
1929          * @param string $action the action to check
1930          * @param $user User user to check
1931          * @param array $errors list of current errors
1932          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1933          * @param $short Boolean short circuit on first error
1934          *
1935          * @return Array list of errors
1936          */
1937         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
1938                 // Use getUserPermissionsErrors instead
1939                 $result = '';
1940                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
1941                         return $result ? array() : array( array( 'badaccess-group0' ) );
1942                 }
1943                 // Check getUserPermissionsErrors hook
1944                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
1945                         $errors = $this->resultToError( $errors, $result );
1946                 }
1947                 // Check getUserPermissionsErrorsExpensive hook
1948                 if (
1949                         $doExpensiveQueries
1950                         && !( $short && count( $errors ) > 0 )
1951                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
1952                 ) {
1953                         $errors = $this->resultToError( $errors, $result );
1954                 }
1955
1956                 return $errors;
1957         }
1958
1959         /**
1960          * Check permissions on special pages & namespaces
1961          *
1962          * @param string $action the action to check
1963          * @param $user User user to check
1964          * @param array $errors list of current errors
1965          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1966          * @param $short Boolean short circuit on first error
1967          *
1968          * @return Array list of errors
1969          */
1970         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1971                 # Only 'createaccount' can be performed on special pages,
1972                 # which don't actually exist in the DB.
1973                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
1974                         $errors[] = array( 'ns-specialprotected' );
1975                 }
1976
1977                 # Check $wgNamespaceProtection for restricted namespaces
1978                 if ( $this->isNamespaceProtected( $user ) ) {
1979                         $ns = $this->mNamespace == NS_MAIN ?
1980                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
1981                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
1982                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
1983                 }
1984
1985                 return $errors;
1986         }
1987
1988         /**
1989          * Check CSS/JS sub-page permissions
1990          *
1991          * @param string $action the action to check
1992          * @param $user User user to check
1993          * @param array $errors list of current errors
1994          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1995          * @param $short Boolean short circuit on first error
1996          *
1997          * @return Array list of errors
1998          */
1999         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2000                 # Protect css/js subpages of user pages
2001                 # XXX: this might be better using restrictions
2002                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2003                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2004                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2005                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2006                                         $errors[] = array( 'mycustomcssprotected' );
2007                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2008                                         $errors[] = array( 'mycustomjsprotected' );
2009                                 }
2010                         } else {
2011                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2012                                         $errors[] = array( 'customcssprotected' );
2013                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2014                                         $errors[] = array( 'customjsprotected' );
2015                                 }
2016                         }
2017                 }
2018
2019                 return $errors;
2020         }
2021
2022         /**
2023          * Check against page_restrictions table requirements on this
2024          * page. The user must possess all required rights for this
2025          * action.
2026          *
2027          * @param string $action the action to check
2028          * @param $user User user to check
2029          * @param array $errors list of current errors
2030          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2031          * @param $short Boolean short circuit on first error
2032          *
2033          * @return Array list of errors
2034          */
2035         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2036                 foreach ( $this->getRestrictions( $action ) as $right ) {
2037                         // Backwards compatibility, rewrite sysop -> editprotected
2038                         if ( $right == 'sysop' ) {
2039                                 $right = 'editprotected';
2040                         }
2041                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2042                         if ( $right == 'autoconfirmed' ) {
2043                                 $right = 'editsemiprotected';
2044                         }
2045                         if ( $right == '' ) {
2046                                 continue;
2047                         }
2048                         if ( !$user->isAllowed( $right ) ) {
2049                                 $errors[] = array( 'protectedpagetext', $right );
2050                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2051                                 $errors[] = array( 'protectedpagetext', 'protect' );
2052                         }
2053                 }
2054
2055                 return $errors;
2056         }
2057
2058         /**
2059          * Check restrictions on cascading pages.
2060          *
2061          * @param string $action the action to check
2062          * @param $user User to check
2063          * @param array $errors list of current errors
2064          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2065          * @param $short Boolean short circuit on first error
2066          *
2067          * @return Array list of errors
2068          */
2069         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2070                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2071                         # We /could/ use the protection level on the source page, but it's
2072                         # fairly ugly as we have to establish a precedence hierarchy for pages
2073                         # included by multiple cascade-protected pages. So just restrict
2074                         # it to people with 'protect' permission, as they could remove the
2075                         # protection anyway.
2076                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2077                         # Cascading protection depends on more than this page...
2078                         # Several cascading protected pages may include this page...
2079                         # Check each cascading level
2080                         # This is only for protection restrictions, not for all actions
2081                         if ( isset( $restrictions[$action] ) ) {
2082                                 foreach ( $restrictions[$action] as $right ) {
2083                                         // Backwards compatibility, rewrite sysop -> editprotected
2084                                         if ( $right == 'sysop' ) {
2085                                                 $right = 'editprotected';
2086                                         }
2087                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2088                                         if ( $right == 'autoconfirmed' ) {
2089                                                 $right = 'editsemiprotected';
2090                                         }
2091                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2092                                                 $pages = '';
2093                                                 foreach ( $cascadingSources as $page ) {
2094                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2095                                                 }
2096                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2097                                         }
2098                                 }
2099                         }
2100                 }
2101
2102                 return $errors;
2103         }
2104
2105         /**
2106          * Check action permissions not already checked in checkQuickPermissions
2107          *
2108          * @param string $action the action to check
2109          * @param $user User to check
2110          * @param array $errors list of current errors
2111          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2112          * @param $short Boolean short circuit on first error
2113          *
2114          * @return Array list of errors
2115          */
2116         private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2117                 global $wgDeleteRevisionsLimit, $wgLang;
2118
2119                 if ( $action == 'protect' ) {
2120                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $doExpensiveQueries, true ) ) ) {
2121                                 // If they can't edit, they shouldn't protect.
2122                                 $errors[] = array( 'protect-cantedit' );
2123                         }
2124                 } elseif ( $action == 'create' ) {
2125                         $title_protection = $this->getTitleProtection();
2126                         if ( $title_protection ) {
2127                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2128                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2129                                 }
2130                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2131                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2132                                 }
2133                                 if ( $title_protection['pt_create_perm'] == ''
2134                                         || !$user->isAllowed( $title_protection['pt_create_perm'] )
2135                                 ) {
2136                                         $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
2137                                 }
2138                         }
2139                 } elseif ( $action == 'move' ) {
2140                         // Check for immobile pages
2141                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2142                                 // Specific message for this case
2143                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2144                         } elseif ( !$this->isMovable() ) {
2145                                 // Less specific message for rarer cases
2146                                 $errors[] = array( 'immobile-source-page' );
2147                         }
2148                 } elseif ( $action == 'move-target' ) {
2149                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2150                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2151                         } elseif ( !$this->isMovable() ) {
2152                                 $errors[] = array( 'immobile-target-page' );
2153                         }
2154                 } elseif ( $action == 'delete' ) {
2155                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2156                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2157                         ) {
2158                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2159                         }
2160                 }
2161                 return $errors;
2162         }
2163
2164         /**
2165          * Check that the user isn't blocked from editing.
2166          *
2167          * @param string $action the action to check
2168          * @param $user User to check
2169          * @param array $errors list of current errors
2170          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2171          * @param $short Boolean short circuit on first error
2172          *
2173          * @return Array list of errors
2174          */
2175         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2176                 // Account creation blocks handled at userlogin.
2177                 // Unblocking handled in SpecialUnblock
2178                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2179                         return $errors;
2180                 }
2181
2182                 global $wgEmailConfirmToEdit;
2183
2184                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2185                         $errors[] = array( 'confirmedittext' );
2186                 }
2187
2188                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2189                         // Don't block the user from editing their own talk page unless they've been
2190                         // explicitly blocked from that too.
2191                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2192                         // @todo FIXME: Pass the relevant context into this function.
2193                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2194                 }
2195
2196                 return $errors;
2197         }
2198
2199         /**
2200          * Check that the user is allowed to read this page.
2201          *
2202          * @param string $action the action to check
2203          * @param $user User to check
2204          * @param array $errors list of current errors
2205          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2206          * @param $short Boolean short circuit on first error
2207          *
2208          * @return Array list of errors
2209          */
2210         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2211                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2212
2213                 $whitelisted = false;
2214                 if ( User::isEveryoneAllowed( 'read' ) ) {
2215                         # Shortcut for public wikis, allows skipping quite a bit of code
2216                         $whitelisted = true;
2217                 } elseif ( $user->isAllowed( 'read' ) ) {
2218                         # If the user is allowed to read pages, he is allowed to read all pages
2219                         $whitelisted = true;
2220                 } elseif ( $this->isSpecial( 'Userlogin' )
2221                         || $this->isSpecial( 'ChangePassword' )
2222                         || $this->isSpecial( 'PasswordReset' )
2223                 ) {
2224                         # Always grant access to the login page.
2225                         # Even anons need to be able to log in.
2226                         $whitelisted = true;
2227                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2228                         # Time to check the whitelist
2229                         # Only do these checks is there's something to check against
2230                         $name = $this->getPrefixedText();
2231                         $dbName = $this->getPrefixedDBkey();
2232
2233                         // Check for explicit whitelisting with and without underscores
2234                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2235                                 $whitelisted = true;
2236                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2237                                 # Old settings might have the title prefixed with
2238                                 # a colon for main-namespace pages
2239                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2240                                         $whitelisted = true;
2241                                 }
2242                         } elseif ( $this->isSpecialPage() ) {
2243                                 # If it's a special page, ditch the subpage bit and check again
2244                                 $name = $this->getDBkey();
2245                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2246                                 if ( $name ) {
2247                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2248                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2249                                                 $whitelisted = true;
2250                                         }
2251                                 }
2252                         }
2253                 }
2254
2255                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2256                         $name = $this->getPrefixedText();
2257                         // Check for regex whitelisting
2258                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2259                                 if ( preg_match( $listItem, $name ) ) {
2260                                         $whitelisted = true;
2261                                         break;
2262                                 }
2263                         }
2264                 }
2265
2266                 if ( !$whitelisted ) {
2267                         # If the title is not whitelisted, give extensions a chance to do so...
2268                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2269                         if ( !$whitelisted ) {
2270                                 $errors[] = $this->missingPermissionError( $action, $short );
2271                         }
2272                 }
2273
2274                 return $errors;
2275         }
2276
2277         /**
2278          * Get a description array when the user doesn't have the right to perform
2279          * $action (i.e. when User::isAllowed() returns false)
2280          *
2281          * @param string $action the action to check
2282          * @param $short Boolean short circuit on first error
2283          * @return Array list of errors
2284          */
2285         private function missingPermissionError( $action, $short ) {
2286                 // We avoid expensive display logic for quickUserCan's and such
2287                 if ( $short ) {
2288                         return array( 'badaccess-group0' );
2289                 }
2290
2291                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2292                         User::getGroupsWithPermission( $action ) );
2293
2294                 if ( count( $groups ) ) {
2295                         global $wgLang;
2296                         return array(
2297                                 'badaccess-groups',
2298                                 $wgLang->commaList( $groups ),
2299                                 count( $groups )
2300                         );
2301                 } else {
2302                         return array( 'badaccess-group0' );
2303                 }
2304         }
2305
2306         /**
2307          * Can $user perform $action on this page? This is an internal function,
2308          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2309          * checks on wfReadOnly() and blocks)
2310          *
2311          * @param string $action action that permission needs to be checked for
2312          * @param $user User to check
2313          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2314          * @param bool $short Set this to true to stop after the first permission error.
2315          * @return Array of arrays of the arguments to wfMessage to explain permissions problems.
2316          */
2317         protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
2318                 wfProfileIn( __METHOD__ );
2319
2320                 # Read has special handling
2321                 if ( $action == 'read' ) {
2322                         $checks = array(
2323                                 'checkPermissionHooks',
2324                                 'checkReadPermissions',
2325                         );
2326                 } else {
2327                         $checks = array(
2328                                 'checkQuickPermissions',
2329                                 'checkPermissionHooks',
2330                                 'checkSpecialsAndNSPermissions',
2331                                 'checkCSSandJSPermissions',
2332                                 'checkPageRestrictions',
2333                                 'checkCascadingSourcesRestrictions',
2334                                 'checkActionPermissions',
2335                                 'checkUserBlock'
2336                         );
2337                 }
2338
2339                 $errors = array();
2340                 while ( count( $checks ) > 0 &&
2341                                 !( $short && count( $errors ) > 0 ) ) {
2342                         $method = array_shift( $checks );
2343                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2344                 }
2345
2346                 wfProfileOut( __METHOD__ );
2347                 return $errors;
2348         }
2349
2350         /**
2351          * Get a filtered list of all restriction types supported by this wiki.
2352          * @param bool $exists True to get all restriction types that apply to
2353          * titles that do exist, False for all restriction types that apply to
2354          * titles that do not exist
2355          * @return array
2356          */
2357         public static function getFilteredRestrictionTypes( $exists = true ) {
2358                 global $wgRestrictionTypes;
2359                 $types = $wgRestrictionTypes;
2360                 if ( $exists ) {
2361                         # Remove the create restriction for existing titles
2362                         $types = array_diff( $types, array( 'create' ) );
2363                 } else {
2364                         # Only the create and upload restrictions apply to non-existing titles
2365                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2366                 }
2367                 return $types;
2368         }
2369
2370         /**
2371          * Returns restriction types for the current Title
2372          *
2373          * @return array applicable restriction types
2374          */
2375         public function getRestrictionTypes() {
2376                 if ( $this->isSpecialPage() ) {
2377                         return array();
2378                 }
2379
2380                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2381
2382                 if ( $this->getNamespace() != NS_FILE ) {
2383                         # Remove the upload restriction for non-file titles
2384                         $types = array_diff( $types, array( 'upload' ) );
2385                 }
2386
2387                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2388
2389                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2390                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2391
2392                 return $types;
2393         }
2394
2395         /**
2396          * Is this title subject to title protection?
2397          * Title protection is the one applied against creation of such title.
2398          *
2399          * @return Mixed An associative array representing any existent title
2400          *   protection, or false if there's none.
2401          */
2402         private function getTitleProtection() {
2403                 // Can't protect pages in special namespaces
2404                 if ( $this->getNamespace() < 0 ) {
2405                         return false;
2406                 }
2407
2408                 // Can't protect pages that exist.
2409                 if ( $this->exists() ) {
2410                         return false;
2411                 }
2412
2413                 if ( !isset( $this->mTitleProtection ) ) {
2414                         $dbr = wfGetDB( DB_SLAVE );
2415                         $res = $dbr->select(
2416                                 'protected_titles',
2417                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2418                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2419                                 __METHOD__
2420                         );
2421
2422                         // fetchRow returns false if there are no rows.
2423                         $this->mTitleProtection = $dbr->fetchRow( $res );
2424                 }
2425                 return $this->mTitleProtection;
2426         }
2427
2428         /**
2429          * Update the title protection status
2430          *
2431          * @deprecated in 1.19; use WikiPage::doUpdateRestrictions() instead.
2432          * @param $create_perm String Permission required for creation
2433          * @param string $reason Reason for protection
2434          * @param string $expiry Expiry timestamp
2435          * @return boolean true
2436          */
2437         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2438                 wfDeprecated( __METHOD__, '1.19' );
2439
2440                 global $wgUser;
2441
2442                 $limit = array( 'create' => $create_perm );
2443                 $expiry = array( 'create' => $expiry );
2444
2445                 $page = WikiPage::factory( $this );
2446                 $cascade = false;
2447                 $status = $page->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $wgUser );
2448
2449                 return $status->isOK();
2450         }
2451
2452         /**
2453          * Remove any title protection due to page existing
2454          */
2455         public function deleteTitleProtection() {
2456                 $dbw = wfGetDB( DB_MASTER );
2457
2458                 $dbw->delete(
2459                         'protected_titles',
2460                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2461                         __METHOD__
2462                 );
2463                 $this->mTitleProtection = false;
2464         }
2465
2466         /**
2467          * Is this page "semi-protected" - the *only* protection levels are listed
2468          * in $wgSemiprotectedRestrictionLevels?
2469          *
2470          * @param string $action Action to check (default: edit)
2471          * @return Bool
2472          */
2473         public function isSemiProtected( $action = 'edit' ) {
2474                 global $wgSemiprotectedRestrictionLevels;
2475
2476                 $restrictions = $this->getRestrictions( $action );
2477                 $semi = $wgSemiprotectedRestrictionLevels;
2478                 if ( !$restrictions || !$semi ) {
2479                         // Not protected, or all protection is full protection
2480                         return false;
2481                 }
2482
2483                 // Remap autoconfirmed to editsemiprotected for BC
2484                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2485                         $semi[$key] = 'editsemiprotected';
2486                 }
2487                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2488                         $restrictions[$key] = 'editsemiprotected';
2489                 }
2490
2491                 return !array_diff( $restrictions, $semi );
2492         }
2493
2494         /**
2495          * Does the title correspond to a protected article?
2496          *
2497          * @param string $action the action the page is protected from,
2498          * by default checks all actions.
2499          * @return Bool
2500          */
2501         public function isProtected( $action = '' ) {
2502                 global $wgRestrictionLevels;
2503
2504                 $restrictionTypes = $this->getRestrictionTypes();
2505
2506                 # Special pages have inherent protection
2507                 if ( $this->isSpecialPage() ) {
2508                         return true;
2509                 }
2510
2511                 # Check regular protection levels
2512                 foreach ( $restrictionTypes as $type ) {
2513                         if ( $action == $type || $action == '' ) {
2514                                 $r = $this->getRestrictions( $type );
2515                                 foreach ( $wgRestrictionLevels as $level ) {
2516                                         if ( in_array( $level, $r ) && $level != '' ) {
2517                                                 return true;
2518                                         }
2519                                 }
2520                         }
2521                 }
2522
2523                 return false;
2524         }
2525
2526         /**
2527          * Determines if $user is unable to edit this page because it has been protected
2528          * by $wgNamespaceProtection.
2529          *
2530          * @param $user User object to check permissions
2531          * @return Bool
2532          */
2533         public function isNamespaceProtected( User $user ) {
2534                 global $wgNamespaceProtection;
2535
2536                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2537                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2538                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2539                                         return true;
2540                                 }
2541                         }
2542                 }
2543                 return false;
2544         }
2545
2546         /**
2547          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2548          *
2549          * @return Bool If the page is subject to cascading restrictions.
2550          */
2551         public function isCascadeProtected() {
2552                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2553                 return ( $sources > 0 );
2554         }
2555
2556         /**
2557          * Cascading protection: Get the source of any cascading restrictions on this page.
2558          *
2559          * @param bool $getPages Whether or not to retrieve the actual pages
2560          *        that the restrictions have come from.
2561          * @return Mixed Array of Title objects of the pages from which cascading restrictions
2562          *     have come, false for none, or true if such restrictions exist, but $getPages
2563          *     was not set.  The restriction array is an array of each type, each of which
2564          *     contains a array of unique groups.
2565          */
2566         public function getCascadeProtectionSources( $getPages = true ) {
2567                 global $wgContLang;
2568                 $pagerestrictions = array();
2569
2570                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2571                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2572                 } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2573                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2574                 }
2575
2576                 wfProfileIn( __METHOD__ );
2577
2578                 $dbr = wfGetDB( DB_SLAVE );
2579
2580                 if ( $this->getNamespace() == NS_FILE ) {
2581                         $tables = array( 'imagelinks', 'page_restrictions' );
2582                         $where_clauses = array(
2583                                 'il_to' => $this->getDBkey(),
2584                                 'il_from=pr_page',
2585                                 'pr_cascade' => 1
2586                         );
2587                 } else {
2588                         $tables = array( 'templatelinks', 'page_restrictions' );
2589                         $where_clauses = array(
2590                                 'tl_namespace' => $this->getNamespace(),
2591                                 'tl_title' => $this->getDBkey(),
2592                                 'tl_from=pr_page',
2593                                 'pr_cascade' => 1
2594                         );
2595                 }
2596
2597                 if ( $getPages ) {
2598                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2599                                 'pr_expiry', 'pr_type', 'pr_level' );
2600                         $where_clauses[] = 'page_id=pr_page';
2601                         $tables[] = 'page';
2602                 } else {
2603                         $cols = array( 'pr_expiry' );
2604                 }
2605
2606                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2607
2608                 $sources = $getPages ? array() : false;
2609                 $now = wfTimestampNow();
2610                 $purgeExpired = false;
2611
2612                 foreach ( $res as $row ) {
2613                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2614                         if ( $expiry > $now ) {
2615                                 if ( $getPages ) {
2616                                         $page_id = $row->pr_page;
2617                                         $page_ns = $row->page_namespace;
2618                                         $page_title = $row->page_title;
2619                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2620                                         # Add groups needed for each restriction type if its not already there
2621                                         # Make sure this restriction type still exists
2622
2623                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2624                                                 $pagerestrictions[$row->pr_type] = array();
2625                                         }
2626
2627                                         if (
2628                                                 isset( $pagerestrictions[$row->pr_type] )
2629                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2630                                         ) {
2631                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2632                                         }
2633                                 } else {
2634                                         $sources = true;
2635                                 }
2636                         } else {
2637                                 // Trigger lazy purge of expired restrictions from the db
2638                                 $purgeExpired = true;
2639                         }
2640                 }
2641                 if ( $purgeExpired ) {
2642                         Title::purgeExpiredRestrictions();
2643                 }
2644
2645                 if ( $getPages ) {
2646                         $this->mCascadeSources = $sources;
2647                         $this->mCascadingRestrictions = $pagerestrictions;
2648                 } else {
2649                         $this->mHasCascadingRestrictions = $sources;
2650                 }
2651
2652                 wfProfileOut( __METHOD__ );
2653                 return array( $sources, $pagerestrictions );
2654         }
2655
2656         /**
2657          * Accessor/initialisation for mRestrictions
2658          *
2659          * @param string $action action that permission needs to be checked for
2660          * @return Array of Strings the array of groups allowed to edit this article
2661          */
2662         public function getRestrictions( $action ) {
2663                 if ( !$this->mRestrictionsLoaded ) {
2664                         $this->loadRestrictions();
2665                 }
2666                 return isset( $this->mRestrictions[$action] )
2667                                 ? $this->mRestrictions[$action]
2668                                 : array();
2669         }
2670
2671         /**
2672          * Get the expiry time for the restriction against a given action
2673          *
2674          * @param $action
2675          * @return String|Bool 14-char timestamp, or 'infinity' if the page is protected forever
2676          *     or not protected at all, or false if the action is not recognised.
2677          */
2678         public function getRestrictionExpiry( $action ) {
2679                 if ( !$this->mRestrictionsLoaded ) {
2680                         $this->loadRestrictions();
2681                 }
2682                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2683         }
2684
2685         /**
2686          * Returns cascading restrictions for the current article
2687          *
2688          * @return Boolean
2689          */
2690         function areRestrictionsCascading() {
2691                 if ( !$this->mRestrictionsLoaded ) {
2692                         $this->loadRestrictions();
2693                 }
2694
2695                 return $this->mCascadeRestriction;
2696         }
2697
2698         /**
2699          * Loads a string into mRestrictions array
2700          *
2701          * @param $res Resource restrictions as an SQL result.
2702          * @param string $oldFashionedRestrictions comma-separated list of page
2703          *        restrictions from page table (pre 1.10)
2704          */
2705         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2706                 $rows = array();
2707
2708                 foreach ( $res as $row ) {
2709                         $rows[] = $row;
2710                 }
2711
2712                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2713         }
2714
2715         /**
2716          * Compiles list of active page restrictions from both page table (pre 1.10)
2717          * and page_restrictions table for this existing page.
2718          * Public for usage by LiquidThreads.
2719          *
2720          * @param array $rows of db result objects
2721          * @param string $oldFashionedRestrictions comma-separated list of page
2722          *        restrictions from page table (pre 1.10)
2723          */
2724         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2725                 global $wgContLang;
2726                 $dbr = wfGetDB( DB_SLAVE );
2727
2728                 $restrictionTypes = $this->getRestrictionTypes();
2729
2730                 foreach ( $restrictionTypes as $type ) {
2731                         $this->mRestrictions[$type] = array();
2732                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2733                 }
2734
2735                 $this->mCascadeRestriction = false;
2736
2737                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2738
2739                 if ( $oldFashionedRestrictions === null ) {
2740                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2741                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2742                 }
2743
2744                 if ( $oldFashionedRestrictions != '' ) {
2745
2746                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2747                                 $temp = explode( '=', trim( $restrict ) );
2748                                 if ( count( $temp ) == 1 ) {
2749                                         // old old format should be treated as edit/move restriction
2750                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2751                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2752                                 } else {
2753                                         $restriction = trim( $temp[1] );
2754                                         if ( $restriction != '' ) { //some old entries are empty
2755                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2756                                         }
2757                                 }
2758                         }
2759
2760                         $this->mOldRestrictions = true;
2761
2762                 }
2763
2764                 if ( count( $rows ) ) {
2765                         # Current system - load second to make them override.
2766                         $now = wfTimestampNow();
2767                         $purgeExpired = false;
2768
2769                         # Cycle through all the restrictions.
2770                         foreach ( $rows as $row ) {
2771
2772                                 // Don't take care of restrictions types that aren't allowed
2773                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2774                                         continue;
2775                                 }
2776
2777                                 // This code should be refactored, now that it's being used more generally,
2778                                 // But I don't really see any harm in leaving it in Block for now -werdna
2779                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2780
2781                                 // Only apply the restrictions if they haven't expired!
2782                                 if ( !$expiry || $expiry > $now ) {
2783                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2784                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2785
2786                                         $this->mCascadeRestriction |= $row->pr_cascade;
2787                                 } else {
2788                                         // Trigger a lazy purge of expired restrictions
2789                                         $purgeExpired = true;
2790                                 }
2791                         }
2792
2793                         if ( $purgeExpired ) {
2794                                 Title::purgeExpiredRestrictions();
2795                         }
2796                 }
2797
2798                 $this->mRestrictionsLoaded = true;
2799         }
2800
2801         /**
2802          * Load restrictions from the page_restrictions table
2803          *
2804          * @param string $oldFashionedRestrictions comma-separated list of page
2805          *        restrictions from page table (pre 1.10)
2806          */
2807         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2808                 global $wgContLang;
2809                 if ( !$this->mRestrictionsLoaded ) {
2810                         if ( $this->exists() ) {
2811                                 $dbr = wfGetDB( DB_SLAVE );
2812
2813                                 $res = $dbr->select(
2814                                         'page_restrictions',
2815                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2816                                         array( 'pr_page' => $this->getArticleID() ),
2817                                         __METHOD__
2818                                 );
2819
2820                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2821                         } else {
2822                                 $title_protection = $this->getTitleProtection();
2823
2824                                 if ( $title_protection ) {
2825                                         $now = wfTimestampNow();
2826                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2827
2828                                         if ( !$expiry || $expiry > $now ) {
2829                                                 // Apply the restrictions
2830                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2831                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2832                                         } else { // Get rid of the old restrictions
2833                                                 Title::purgeExpiredRestrictions();
2834                                                 $this->mTitleProtection = false;
2835                                         }
2836                                 } else {
2837                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2838                                 }
2839                                 $this->mRestrictionsLoaded = true;
2840                         }
2841                 }
2842         }
2843
2844         /**
2845          * Flush the protection cache in this object and force reload from the database.
2846          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2847          */
2848         public function flushRestrictions() {
2849                 $this->mRestrictionsLoaded = false;
2850                 $this->mTitleProtection = null;
2851         }
2852
2853         /**
2854          * Purge expired restrictions from the page_restrictions table
2855          */
2856         static function purgeExpiredRestrictions() {
2857                 if ( wfReadOnly() ) {
2858                         return;
2859                 }
2860
2861                 $method = __METHOD__;
2862                 $dbw = wfGetDB( DB_MASTER );
2863                 $dbw->onTransactionIdle( function() use ( $dbw, $method ) {
2864                         $dbw->delete(
2865                                 'page_restrictions',
2866                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2867                                 $method
2868                         );
2869                         $dbw->delete(
2870                                 'protected_titles',
2871                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2872                                 $method
2873                         );
2874                 } );
2875         }
2876
2877         /**
2878          * Does this have subpages?  (Warning, usually requires an extra DB query.)
2879          *
2880          * @return Bool
2881          */
2882         public function hasSubpages() {
2883                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
2884                         # Duh
2885                         return false;
2886                 }
2887
2888                 # We dynamically add a member variable for the purpose of this method
2889                 # alone to cache the result.  There's no point in having it hanging
2890                 # around uninitialized in every Title object; therefore we only add it
2891                 # if needed and don't declare it statically.
2892                 if ( isset( $this->mHasSubpages ) ) {
2893                         return $this->mHasSubpages;
2894                 }
2895
2896                 $subpages = $this->getSubpages( 1 );
2897                 if ( $subpages instanceof TitleArray ) {
2898                         return $this->mHasSubpages = (bool)$subpages->count();
2899                 }
2900                 return $this->mHasSubpages = false;
2901         }
2902
2903         /**
2904          * Get all subpages of this page.
2905          *
2906          * @param int $limit maximum number of subpages to fetch; -1 for no limit
2907          * @return mixed TitleArray, or empty array if this page's namespace
2908          *  doesn't allow subpages
2909          */
2910         public function getSubpages( $limit = -1 ) {
2911                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
2912                         return array();
2913                 }
2914
2915                 $dbr = wfGetDB( DB_SLAVE );
2916                 $conds['page_namespace'] = $this->getNamespace();
2917                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
2918                 $options = array();
2919                 if ( $limit > -1 ) {
2920                         $options['LIMIT'] = $limit;
2921                 }
2922                 return $this->mSubpages = TitleArray::newFromResult(
2923                         $dbr->select( 'page',
2924                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
2925                                 $conds,
2926                                 __METHOD__,
2927                                 $options
2928                         )
2929                 );
2930         }
2931
2932         /**
2933          * Is there a version of this page in the deletion archive?
2934          *
2935          * @return Int the number of archived revisions
2936          */
2937         public function isDeleted() {
2938                 if ( $this->getNamespace() < 0 ) {
2939                         $n = 0;
2940                 } else {
2941                         $dbr = wfGetDB( DB_SLAVE );
2942
2943                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
2944                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2945                                 __METHOD__
2946                         );
2947                         if ( $this->getNamespace() == NS_FILE ) {
2948                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
2949                                         array( 'fa_name' => $this->getDBkey() ),
2950                                         __METHOD__
2951                                 );
2952                         }
2953                 }
2954                 return (int)$n;
2955         }
2956
2957         /**
2958          * Is there a version of this page in the deletion archive?
2959          *
2960          * @return Boolean
2961          */
2962         public function isDeletedQuick() {
2963                 if ( $this->getNamespace() < 0 ) {
2964                         return false;
2965                 }
2966                 $dbr = wfGetDB( DB_SLAVE );
2967                 $deleted = (bool)$dbr->selectField( 'archive', '1',
2968                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2969                         __METHOD__
2970                 );
2971                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
2972                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
2973                                 array( 'fa_name' => $this->getDBkey() ),
2974                                 __METHOD__
2975                         );
2976                 }
2977                 return $deleted;
2978         }
2979
2980         /**
2981          * Get the article ID for this Title from the link cache,
2982          * adding it if necessary
2983          *
2984          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select
2985          *  for update
2986          * @return Int the ID
2987          */
2988         public function getArticleID( $flags = 0 ) {
2989                 if ( $this->getNamespace() < 0 ) {
2990                         return $this->mArticleID = 0;
2991                 }
2992                 $linkCache = LinkCache::singleton();
2993                 if ( $flags & self::GAID_FOR_UPDATE ) {
2994                         $oldUpdate = $linkCache->forUpdate( true );
2995                         $linkCache->clearLink( $this );
2996                         $this->mArticleID = $linkCache->addLinkObj( $this );
2997                         $linkCache->forUpdate( $oldUpdate );
2998                 } else {
2999                         if ( -1 == $this->mArticleID ) {
3000                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3001                         }
3002                 }
3003                 return $this->mArticleID;
3004         }
3005
3006         /**
3007          * Is this an article that is a redirect page?
3008          * Uses link cache, adding it if necessary
3009          *
3010          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3011          * @return Bool
3012          */
3013         public function isRedirect( $flags = 0 ) {
3014                 if ( !is_null( $this->mRedirect ) ) {
3015                         return $this->mRedirect;
3016                 }
3017                 # Calling getArticleID() loads the field from cache as needed
3018                 if ( !$this->getArticleID( $flags ) ) {
3019                         return $this->mRedirect = false;
3020                 }
3021
3022                 $linkCache = LinkCache::singleton();
3023                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3024                 if ( $cached === null ) {
3025                         # Trust LinkCache's state over our own
3026                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3027                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3028                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3029                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3030                         # LinkCache to refresh its data from the master.
3031                         return $this->mRedirect = false;
3032                 }
3033
3034                 $this->mRedirect = (bool)$cached;
3035
3036                 return $this->mRedirect;
3037         }
3038
3039         /**
3040          * What is the length of this page?
3041          * Uses link cache, adding it if necessary
3042          *
3043          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3044          * @return Int
3045          */
3046         public function getLength( $flags = 0 ) {
3047                 if ( $this->mLength != -1 ) {
3048                         return $this->mLength;
3049                 }
3050                 # Calling getArticleID() loads the field from cache as needed
3051                 if ( !$this->getArticleID( $flags ) ) {
3052                         return $this->mLength = 0;
3053                 }
3054                 $linkCache = LinkCache::singleton();
3055                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3056                 if ( $cached === null ) {
3057                         # Trust LinkCache's state over our own, as for isRedirect()
3058                         return $this->mLength = 0;
3059                 }
3060
3061                 $this->mLength = intval( $cached );
3062
3063                 return $this->mLength;
3064         }
3065
3066         /**
3067          * What is the page_latest field for this page?
3068          *
3069          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3070          * @return Int or 0 if the page doesn't exist
3071          */
3072         public function getLatestRevID( $flags = 0 ) {
3073                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3074                         return intval( $this->mLatestID );
3075                 }
3076                 # Calling getArticleID() loads the field from cache as needed
3077                 if ( !$this->getArticleID( $flags ) ) {
3078                         return $this->mLatestID = 0;
3079                 }
3080                 $linkCache = LinkCache::singleton();
3081                 $linkCache->addLinkObj( $this );
3082                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3083                 if ( $cached === null ) {
3084                         # Trust LinkCache's state over our own, as for isRedirect()
3085                         return $this->mLatestID = 0;
3086                 }
3087
3088                 $this->mLatestID = intval( $cached );
3089
3090                 return $this->mLatestID;
3091         }
3092
3093         /**
3094          * This clears some fields in this object, and clears any associated
3095          * keys in the "bad links" section of the link cache.
3096          *
3097          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3098          * loading of the new page_id. It's also called from
3099          * WikiPage::doDeleteArticleReal()
3100          *
3101          * @param int $newid the new Article ID
3102          */
3103         public function resetArticleID( $newid ) {
3104                 $linkCache = LinkCache::singleton();
3105                 $linkCache->clearLink( $this );
3106
3107                 if ( $newid === false ) {
3108                         $this->mArticleID = -1;
3109                 } else {
3110                         $this->mArticleID = intval( $newid );
3111                 }
3112                 $this->mRestrictionsLoaded = false;
3113                 $this->mRestrictions = array();
3114                 $this->mRedirect = null;
3115                 $this->mLength = -1;
3116                 $this->mLatestID = false;
3117                 $this->mContentModel = false;
3118                 $this->mEstimateRevisions = null;
3119                 $this->mPageLanguage = false;
3120         }
3121
3122         /**
3123          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3124          *
3125          * @param string $text containing title to capitalize
3126          * @param int $ns namespace index, defaults to NS_MAIN
3127          * @return String containing capitalized title
3128          */
3129         public static function capitalize( $text, $ns = NS_MAIN ) {
3130                 global $wgContLang;
3131
3132                 if ( MWNamespace::isCapitalized( $ns ) ) {
3133                         return $wgContLang->ucfirst( $text );
3134                 } else {
3135                         return $text;
3136                 }
3137         }
3138
3139         /**
3140          * Secure and split - main initialisation function for this object
3141          *
3142          * Assumes that mDbkeyform has been set, and is urldecoded
3143          * and uses underscores, but not otherwise munged.  This function
3144          * removes illegal characters, splits off the interwiki and
3145          * namespace prefixes, sets the other forms, and canonicalizes
3146          * everything.
3147          *
3148          * @return Bool true on success
3149          */
3150         private function secureAndSplit() {
3151                 global $wgContLang, $wgLocalInterwiki;
3152
3153                 # Initialisation
3154                 $this->mInterwiki = $this->mFragment = '';
3155                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3156
3157                 $dbkey = $this->mDbkeyform;
3158
3159                 # Strip Unicode bidi override characters.
3160                 # Sometimes they slip into cut-n-pasted page titles, where the
3161                 # override chars get included in list displays.
3162                 $dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );
3163
3164                 # Clean up whitespace
3165                 # Note: use of the /u option on preg_replace here will cause
3166                 # input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
3167                 # conveniently disabling them.
3168                 $dbkey = preg_replace( '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u', '_', $dbkey );
3169                 $dbkey = trim( $dbkey, '_' );
3170
3171                 if ( strpos( $dbkey, UTF8_REPLACEMENT ) !== false ) {
3172                         # Contained illegal UTF-8 sequences or forbidden Unicode chars.
3173                         return false;
3174                 }
3175
3176                 $this->mDbkeyform = $dbkey;
3177
3178                 # Initial colon indicates main namespace rather than specified default
3179                 # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
3180                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3181                         $this->mNamespace = NS_MAIN;
3182                         $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
3183                         $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
3184                 }
3185
3186                 if ( $dbkey == '' ) {
3187                         return false;
3188                 }
3189
3190                 # Namespace or interwiki prefix
3191                 $firstPass = true;
3192                 $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
3193                 do {
3194                         $m = array();
3195                         if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
3196                                 $p = $m[1];
3197                                 if ( ( $ns = $wgContLang->getNsIndex( $p ) ) !== false ) {
3198                                         # Ordinary namespace
3199                                         $dbkey = $m[2];
3200                                         $this->mNamespace = $ns;
3201                                         # For Talk:X pages, check if X has a "namespace" prefix
3202                                         if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
3203                                                 if ( $wgContLang->getNsIndex( $x[1] ) ) {
3204                                                         # Disallow Talk:File:x type titles...
3205                                                         return false;
3206                                                 } elseif ( Interwiki::isValidInterwiki( $x[1] ) ) {
3207                                                         # Disallow Talk:Interwiki:x type titles...
3208                                                         return false;
3209                                                 }
3210                                         }
3211                                 } elseif ( Interwiki::isValidInterwiki( $p ) ) {
3212                                         if ( !$firstPass ) {
3213                                                 # Can't make a local interwiki link to an interwiki link.
3214                                                 # That's just crazy!
3215                                                 return false;
3216                                         }
3217
3218                                         # Interwiki link
3219                                         $dbkey = $m[2];
3220                                         $this->mInterwiki = $wgContLang->lc( $p );
3221
3222                                         # Redundant interwiki prefix to the local wiki
3223                                         if ( $wgLocalInterwiki !== false
3224                                                 && 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki )
3225                                         ) {
3226                                                 if ( $dbkey == '' ) {
3227                                                         # Can't have an empty self-link
3228                                                         return false;
3229                                                 }
3230                                                 $this->mInterwiki = '';
3231                                                 $firstPass = false;
3232                                                 # Do another namespace split...
3233                                                 continue;
3234                                         }
3235
3236                                         # If there's an initial colon after the interwiki, that also
3237                                         # resets the default namespace
3238                                         if ( $dbkey !== '' && $dbkey[0] == ':' ) {
3239                                                 $this->mNamespace = NS_MAIN;
3240                                                 $dbkey = substr( $dbkey, 1 );
3241                                         }
3242                                 }
3243                                 # If there's no recognized interwiki or namespace,
3244                                 # then let the colon expression be part of the title.
3245                         }
3246                         break;
3247                 } while ( true );
3248
3249                 # We already know that some pages won't be in the database!
3250                 if ( $this->mInterwiki != '' || NS_SPECIAL == $this->mNamespace ) {
3251                         $this->mArticleID = 0;
3252                 }
3253                 $fragment = strstr( $dbkey, '#' );
3254                 if ( false !== $fragment ) {
3255                         $this->setFragment( $fragment );
3256                         $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
3257                         # remove whitespace again: prevents "Foo_bar_#"
3258                         # becoming "Foo_bar_"
3259                         $dbkey = preg_replace( '/_*$/', '', $dbkey );
3260                 }
3261
3262                 # Reject illegal characters.
3263                 $rxTc = self::getTitleInvalidRegex();
3264                 if ( preg_match( $rxTc, $dbkey ) ) {
3265                         return false;
3266                 }
3267
3268                 # Pages with "/./" or "/../" appearing in the URLs will often be un-
3269                 # reachable due to the way web browsers deal with 'relative' URLs.
3270                 # Also, they conflict with subpage syntax.  Forbid them explicitly.
3271                 if (
3272                         strpos( $dbkey, '.' ) !== false &&
3273                         (
3274                                 $dbkey === '.' || $dbkey === '..' ||
3275                                 strpos( $dbkey, './' ) === 0 ||
3276                                 strpos( $dbkey, '../' ) === 0 ||
3277                                 strpos( $dbkey, '/./' ) !== false ||
3278                                 strpos( $dbkey, '/../' ) !== false ||
3279                                 substr( $dbkey, -2 ) == '/.' ||
3280                                 substr( $dbkey, -3 ) == '/..'
3281                         )
3282                 ) {
3283                         return false;
3284                 }
3285
3286                 # Magic tilde sequences? Nu-uh!
3287                 if ( strpos( $dbkey, '~~~' ) !== false ) {
3288                         return false;
3289                 }
3290
3291                 # Limit the size of titles to 255 bytes. This is typically the size of the
3292                 # underlying database field. We make an exception for special pages, which
3293                 # don't need to be stored in the database, and may edge over 255 bytes due
3294                 # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
3295                 if (
3296                         ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 )
3297                         || strlen( $dbkey ) > 512
3298                 ) {
3299                         return false;
3300                 }
3301
3302                 # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
3303                 # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
3304                 # other site might be case-sensitive.
3305                 $this->mUserCaseDBKey = $dbkey;
3306                 if ( $this->mInterwiki == '' ) {
3307                         $dbkey = self::capitalize( $dbkey, $this->mNamespace );
3308                 }
3309
3310                 # Can't make a link to a namespace alone... "empty" local links can only be
3311                 # self-links with a fragment identifier.
3312                 # TODO: Why do we exclude NS_MAIN (bug 54044)
3313                 if ( $dbkey == '' && $this->mInterwiki == '' && $this->mNamespace != NS_MAIN ) {
3314                         return false;
3315                 }
3316
3317                 // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
3318                 // IP names are not allowed for accounts, and can only be referring to
3319                 // edits from the IP. Given '::' abbreviations and caps/lowercaps,
3320                 // there are numerous ways to present the same IP. Having sp:contribs scan
3321                 // them all is silly and having some show the edits and others not is
3322                 // inconsistent. Same for talk/userpages. Keep them normalized instead.
3323                 $dbkey = ( $this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK )
3324                         ? IP::sanitizeIP( $dbkey )
3325                         : $dbkey;
3326
3327                 // Any remaining initial :s are illegal.
3328                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3329                         return false;
3330                 }
3331
3332                 # Fill fields
3333                 $this->mDbkeyform = $dbkey;
3334                 $this->mUrlform = wfUrlencode( $dbkey );
3335
3336                 $this->mTextform = str_replace( '_', ' ', $dbkey );
3337
3338                 return true;
3339         }
3340
3341         /**
3342          * Get an array of Title objects linking to this Title
3343          * Also stores the IDs in the link cache.
3344          *
3345          * WARNING: do not use this function on arbitrary user-supplied titles!
3346          * On heavily-used templates it will max out the memory.
3347          *
3348          * @param array $options may be FOR UPDATE
3349          * @param string $table table name
3350          * @param string $prefix fields prefix
3351          * @return Array of Title objects linking here
3352          */
3353         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3354                 if ( count( $options ) > 0 ) {
3355                         $db = wfGetDB( DB_MASTER );
3356                 } else {
3357                         $db = wfGetDB( DB_SLAVE );
3358                 }
3359
3360                 $res = $db->select(
3361                         array( 'page', $table ),
3362                         self::getSelectFields(),
3363                         array(
3364                                 "{$prefix}_from=page_id",
3365                                 "{$prefix}_namespace" => $this->getNamespace(),
3366                                 "{$prefix}_title" => $this->getDBkey() ),
3367                         __METHOD__,
3368                         $options
3369                 );
3370
3371                 $retVal = array();
3372                 if ( $res->numRows() ) {
3373                         $linkCache = LinkCache::singleton();
3374                         foreach ( $res as $row ) {
3375                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3376                                 if ( $titleObj ) {
3377                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3378                                         $retVal[] = $titleObj;
3379                                 }
3380                         }
3381                 }
3382                 return $retVal;
3383         }
3384
3385         /**
3386          * Get an array of Title objects using this Title as a template
3387          * Also stores the IDs in the link cache.
3388          *
3389          * WARNING: do not use this function on arbitrary user-supplied titles!
3390          * On heavily-used templates it will max out the memory.
3391          *
3392          * @param array $options may be FOR UPDATE
3393          * @return Array of Title the Title objects linking here
3394          */
3395         public function getTemplateLinksTo( $options = array() ) {
3396                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3397         }
3398
3399         /**
3400          * Get an array of Title objects linked from this Title
3401          * Also stores the IDs in the link cache.
3402          *
3403          * WARNING: do not use this function on arbitrary user-supplied titles!
3404          * On heavily-used templates it will max out the memory.
3405          *
3406          * @param array $options may be FOR UPDATE
3407          * @param string $table table name
3408          * @param string $prefix fields prefix
3409          * @return Array of Title objects linking here
3410          */
3411         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3412                 global $wgContentHandlerUseDB;
3413
3414                 $id = $this->getArticleID();
3415
3416                 # If the page doesn't exist; there can't be any link from this page
3417                 if ( !$id ) {
3418                         return array();
3419                 }
3420
3421                 if ( count( $options ) > 0 ) {
3422                         $db = wfGetDB( DB_MASTER );
3423                 } else {
3424                         $db = wfGetDB( DB_SLAVE );
3425                 }
3426
3427                 $namespaceFiled = "{$prefix}_namespace";
3428                 $titleField = "{$prefix}_title";
3429
3430                 $fields = array( $namespaceFiled, $titleField, 'page_id', 'page_len', 'page_is_redirect', 'page_latest' );
3431                 if ( $wgContentHandlerUseDB ) {
3432                         $fields[] = 'page_content_model';
3433                 }
3434
3435                 $res = $db->select(
3436                         array( $table, 'page' ),
3437                         $fields,
3438                         array( "{$prefix}_from" => $id ),
3439                         __METHOD__,
3440                         $options,
3441                         array( 'page' => array( 'LEFT JOIN', array( "page_namespace=$namespaceFiled", "page_title=$titleField" ) ) )
3442                 );
3443
3444                 $retVal = array();
3445                 if ( $res->numRows() ) {
3446                         $linkCache = LinkCache::singleton();
3447                         foreach ( $res as $row ) {
3448                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3449                                 if ( $titleObj ) {
3450                                         if ( $row->page_id ) {
3451                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3452                                         } else {
3453                                                 $linkCache->addBadLinkObj( $titleObj );
3454                                         }
3455                                         $retVal[] = $titleObj;
3456                                 }
3457                         }
3458                 }
3459                 return $retVal;
3460         }
3461
3462         /**
3463          * Get an array of Title objects used on this Title as a template
3464          * Also stores the IDs in the link cache.
3465          *
3466          * WARNING: do not use this function on arbitrary user-supplied titles!
3467          * On heavily-used templates it will max out the memory.
3468          *
3469          * @param array $options may be FOR UPDATE
3470          * @return Array of Title the Title objects used here
3471          */
3472         public function getTemplateLinksFrom( $options = array() ) {
3473                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3474         }
3475
3476         /**
3477          * Get an array of Title objects referring to non-existent articles linked from this page
3478          *
3479          * @todo check if needed (used only in SpecialBrokenRedirects.php, and should use redirect table in this case)
3480          * @return Array of Title the Title objects
3481          */
3482         public function getBrokenLinksFrom() {
3483                 if ( $this->getArticleID() == 0 ) {
3484                         # All links from article ID 0 are false positives
3485                         return array();
3486                 }
3487
3488                 $dbr = wfGetDB( DB_SLAVE );
3489                 $res = $dbr->select(
3490                         array( 'page', 'pagelinks' ),
3491                         array( 'pl_namespace', 'pl_title' ),
3492                         array(
3493                                 'pl_from' => $this->getArticleID(),
3494                                 'page_namespace IS NULL'
3495                         ),
3496                         __METHOD__, array(),
3497                         array(
3498                                 'page' => array(
3499                                         'LEFT JOIN',
3500                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3501                                 )
3502                         )
3503                 );
3504
3505                 $retVal = array();
3506                 foreach ( $res as $row ) {
3507                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3508                 }
3509                 return $retVal;
3510         }
3511
3512         /**
3513          * Get a list of URLs to purge from the Squid cache when this
3514          * page changes
3515          *
3516          * @return Array of String the URLs
3517          */
3518         public function getSquidURLs() {
3519                 $urls = array(
3520                         $this->getInternalURL(),
3521                         $this->getInternalURL( 'action=history' )
3522                 );
3523
3524                 $pageLang = $this->getPageLanguage();
3525                 if ( $pageLang->hasVariants() ) {
3526                         $variants = $pageLang->getVariants();
3527                         foreach ( $variants as $vCode ) {
3528                                 $urls[] = $this->getInternalURL( '', $vCode );
3529                         }
3530                 }
3531
3532                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3533                 return $urls;
3534         }
3535
3536         /**
3537          * Purge all applicable Squid URLs
3538          */
3539         public function purgeSquid() {
3540                 global $wgUseSquid;
3541                 if ( $wgUseSquid ) {
3542                         $urls = $this->getSquidURLs();
3543                         $u = new SquidUpdate( $urls );
3544                         $u->doUpdate();
3545                 }
3546         }
3547
3548         /**
3549          * Move this page without authentication
3550          *
3551          * @param $nt Title the new page Title
3552          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3553          */
3554         public function moveNoAuth( &$nt ) {
3555                 return $this->moveTo( $nt, false );
3556         }
3557
3558         /**
3559          * Check whether a given move operation would be valid.
3560          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3561          *
3562          * @param $nt Title the new title
3563          * @param bool $auth indicates whether $wgUser's permissions
3564          *  should be checked
3565          * @param string $reason is the log summary of the move, used for spam checking
3566          * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
3567          */
3568         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3569                 global $wgUser, $wgContentHandlerUseDB;
3570
3571                 $errors = array();
3572                 if ( !$nt ) {
3573                         // Normally we'd add this to $errors, but we'll get
3574                         // lots of syntax errors if $nt is not an object
3575                         return array( array( 'badtitletext' ) );
3576                 }
3577                 if ( $this->equals( $nt ) ) {
3578                         $errors[] = array( 'selfmove' );
3579                 }
3580                 if ( !$this->isMovable() ) {
3581                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3582                 }
3583                 if ( $nt->getInterwiki() != '' ) {
3584                         $errors[] = array( 'immobile-target-namespace-iw' );
3585                 }
3586                 if ( !$nt->isMovable() ) {
3587                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3588                 }
3589
3590                 $oldid = $this->getArticleID();
3591                 $newid = $nt->getArticleID();
3592
3593                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3594                         $errors[] = array( 'articleexists' );
3595                 }
3596                 if (
3597                         ( $this->getDBkey() == '' ) ||
3598                         ( !$oldid ) ||
3599                         ( $nt->getDBkey() == '' )
3600                 ) {
3601                         $errors[] = array( 'badarticleerror' );
3602                 }
3603
3604                 // Content model checks
3605                 if ( !$wgContentHandlerUseDB &&
3606                                 $this->getContentModel() !== $nt->getContentModel() ) {
3607                         // can't move a page if that would change the page's content model
3608                         $errors[] = array(
3609                                 'bad-target-model',
3610                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3611                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3612                         );
3613                 }
3614
3615                 // Image-specific checks
3616                 if ( $this->getNamespace() == NS_FILE ) {
3617                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3618                 }
3619
3620                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3621                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3622                 }
3623
3624                 if ( $auth ) {
3625                         $errors = wfMergeErrorArrays( $errors,
3626                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3627                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3628                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3629                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3630                 }
3631
3632                 $match = EditPage::matchSummarySpamRegex( $reason );
3633                 if ( $match !== false ) {
3634                         // This is kind of lame, won't display nice
3635                         $errors[] = array( 'spamprotectiontext' );
3636                 }
3637
3638                 $err = null;
3639                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3640                         $errors[] = array( 'hookaborted', $err );
3641                 }
3642
3643                 # The move is allowed only if (1) the target doesn't exist, or
3644                 # (2) the target is a redirect to the source, and has no history
3645                 # (so we can undo bad moves right after they're done).
3646
3647                 if ( 0 != $newid ) { # Target exists; check for validity
3648                         if ( !$this->isValidMoveTarget( $nt ) ) {
3649                                 $errors[] = array( 'articleexists' );
3650                         }
3651                 } else {
3652                         $tp = $nt->getTitleProtection();
3653                         $right = $tp['pt_create_perm'];
3654                         if ( $right == 'sysop' ) {
3655                                 $right = 'editprotected'; // B/C
3656                         }
3657                         if ( $right == 'autoconfirmed' ) {
3658                                 $right = 'editsemiprotected'; // B/C
3659                         }
3660                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3661                                 $errors[] = array( 'cantmove-titleprotected' );
3662                         }
3663                 }
3664                 if ( empty( $errors ) ) {
3665                         return true;
3666                 }
3667                 return $errors;
3668         }
3669
3670         /**
3671          * Check if the requested move target is a valid file move target
3672          * @param Title $nt Target title
3673          * @return array List of errors
3674          */
3675         protected function validateFileMoveOperation( $nt ) {
3676                 global $wgUser;
3677
3678                 $errors = array();
3679
3680                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3681
3682                 $file = wfLocalFile( $this );
3683                 if ( $file->exists() ) {
3684                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3685                                 $errors[] = array( 'imageinvalidfilename' );
3686                         }
3687                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3688                                 $errors[] = array( 'imagetypemismatch' );
3689                         }
3690                 }
3691
3692                 if ( $nt->getNamespace() != NS_FILE ) {
3693                         $errors[] = array( 'imagenocrossnamespace' );
3694                         // From here we want to do checks on a file object, so if we can't
3695                         // create one, we must return.
3696                         return $errors;
3697                 }
3698
3699                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3700
3701                 $destFile = wfLocalFile( $nt );
3702                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3703                         $errors[] = array( 'file-exists-sharedrepo' );
3704                 }
3705
3706                 return $errors;
3707         }
3708
3709         /**
3710          * Move a title to a new location
3711          *
3712          * @param $nt Title the new title
3713          * @param bool $auth indicates whether $wgUser's permissions
3714          *  should be checked
3715          * @param string $reason the reason for the move
3716          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3717          *  Ignored if the user doesn't have the suppressredirect right.
3718          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3719          */
3720         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3721                 global $wgUser;
3722                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3723                 if ( is_array( $err ) ) {
3724                         // Auto-block user's IP if the account was "hard" blocked
3725                         $wgUser->spreadAnyEditBlock();
3726                         return $err;
3727                 }
3728                 // Check suppressredirect permission
3729                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3730                         $createRedirect = true;
3731                 }
3732
3733                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3734
3735                 // If it is a file, move it first.
3736                 // It is done before all other moving stuff is done because it's hard to revert.
3737                 $dbw = wfGetDB( DB_MASTER );
3738                 if ( $this->getNamespace() == NS_FILE ) {
3739                         $file = wfLocalFile( $this );
3740                         if ( $file->exists() ) {
3741                                 $status = $file->move( $nt );
3742                                 if ( !$status->isOk() ) {
3743                                         return $status->getErrorsArray();
3744                                 }
3745                         }
3746                         // Clear RepoGroup process cache
3747                         RepoGroup::singleton()->clearCache( $this );
3748                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3749                 }
3750
3751                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3752                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3753                 $protected = $this->isProtected();
3754
3755                 // Do the actual move
3756                 $this->moveToInternal( $nt, $reason, $createRedirect );
3757
3758                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3759                 // cl_timestamp, which may disturb time-based lists on some sites.
3760                 $prefixes = $dbw->select(
3761                         'categorylinks',
3762                         array( 'cl_sortkey_prefix', 'cl_to' ),
3763                         array( 'cl_from' => $pageid ),
3764                         __METHOD__
3765                 );
3766                 foreach ( $prefixes as $prefixRow ) {
3767                         $prefix = $prefixRow->cl_sortkey_prefix;
3768                         $catTo = $prefixRow->cl_to;
3769                         $dbw->update( 'categorylinks',
3770                                 array(
3771                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3772                                                 $nt->getCategorySortkey( $prefix ) ),
3773                                         'cl_timestamp=cl_timestamp' ),
3774                                 array(
3775                                         'cl_from' => $pageid,
3776                                         'cl_to' => $catTo ),
3777                                 __METHOD__
3778                         );
3779                 }
3780
3781                 $redirid = $this->getArticleID();
3782
3783                 if ( $protected ) {
3784                         # Protect the redirect title as the title used to be...
3785                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3786                                 array(
3787                                         'pr_page' => $redirid,
3788                                         'pr_type' => 'pr_type',
3789                                         'pr_level' => 'pr_level',
3790                                         'pr_cascade' => 'pr_cascade',
3791                                         'pr_user' => 'pr_user',
3792                                         'pr_expiry' => 'pr_expiry'
3793                                 ),
3794                                 array( 'pr_page' => $pageid ),
3795                                 __METHOD__,
3796                                 array( 'IGNORE' )
3797                         );
3798                         # Update the protection log
3799                         $log = new LogPage( 'protect' );
3800                         $comment = wfMessage(
3801                                 'prot_1movedto2',
3802                                 $this->getPrefixedText(),
3803                                 $nt->getPrefixedText()
3804                         )->inContentLanguage()->text();
3805                         if ( $reason ) {
3806                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3807                         }
3808                         // @todo FIXME: $params?
3809                         $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ), $wgUser );
3810                 }
3811
3812                 # Update watchlists
3813                 $oldnamespace = MWNamespace::getSubject( $this->getNamespace() );
3814                 $newnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3815                 $oldtitle = $this->getDBkey();
3816                 $newtitle = $nt->getDBkey();
3817
3818                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3819                         WatchedItem::duplicateEntries( $this, $nt );
3820                 }
3821
3822                 $dbw->commit( __METHOD__ );
3823
3824                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
3825                 return true;
3826         }
3827
3828         /**
3829          * Move page to a title which is either a redirect to the
3830          * source page or nonexistent
3831          *
3832          * @param $nt Title the page to move to, which should be a redirect or nonexistent
3833          * @param string $reason The reason for the move
3834          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3835          *   if the user has the suppressredirect right
3836          * @throws MWException
3837          */
3838         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3839                 global $wgUser, $wgContLang;
3840
3841                 if ( $nt->exists() ) {
3842                         $moveOverRedirect = true;
3843                         $logType = 'move_redir';
3844                 } else {
3845                         $moveOverRedirect = false;
3846                         $logType = 'move';
3847                 }
3848
3849                 if ( $createRedirect ) {
3850                         $contentHandler = ContentHandler::getForTitle( $this );
3851                         $redirectContent = $contentHandler->makeRedirectContent( $nt,
3852                                 wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3853
3854                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3855                 } else {
3856                         $redirectContent = null;
3857                 }
3858
3859                 $logEntry = new ManualLogEntry( 'move', $logType );
3860                 $logEntry->setPerformer( $wgUser );
3861                 $logEntry->setTarget( $this );
3862                 $logEntry->setComment( $reason );
3863                 $logEntry->setParameters( array(
3864                         '4::target' => $nt->getPrefixedText(),
3865                         '5::noredir' => $redirectContent ? '0': '1',
3866                 ) );
3867
3868                 $formatter = LogFormatter::newFromEntry( $logEntry );
3869                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3870                 $comment = $formatter->getPlainActionText();
3871                 if ( $reason ) {
3872                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3873                 }
3874                 # Truncate for whole multibyte characters.
3875                 $comment = $wgContLang->truncate( $comment, 255 );
3876
3877                 $oldid = $this->getArticleID();
3878
3879                 $dbw = wfGetDB( DB_MASTER );
3880
3881                 $newpage = WikiPage::factory( $nt );
3882
3883                 if ( $moveOverRedirect ) {
3884                         $newid = $nt->getArticleID();
3885
3886                         # Delete the old redirect. We don't save it to history since
3887                         # by definition if we've got here it's rather uninteresting.
3888                         # We have to remove it so that the next step doesn't trigger
3889                         # a conflict on the unique namespace+title index...
3890                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3891
3892                         $newpage->doDeleteUpdates( $newid );
3893                 }
3894
3895                 # Save a null revision in the page's history notifying of the move
3896                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
3897                 if ( !is_object( $nullRevision ) ) {
3898                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3899                 }
3900
3901                 $nullRevision->insertOn( $dbw );
3902
3903                 # Change the name of the target page:
3904                 $dbw->update( 'page',
3905                         /* SET */ array(
3906                                 'page_namespace' => $nt->getNamespace(),
3907                                 'page_title' => $nt->getDBkey(),
3908                         ),
3909                         /* WHERE */ array( 'page_id' => $oldid ),
3910                         __METHOD__
3911                 );
3912
3913                 // clean up the old title before reset article id - bug 45348
3914                 if ( !$redirectContent ) {
3915                         WikiPage::onArticleDelete( $this );
3916                 }
3917
3918                 $this->resetArticleID( 0 ); // 0 == non existing
3919                 $nt->resetArticleID( $oldid );
3920                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
3921
3922                 $newpage->updateRevisionOn( $dbw, $nullRevision );
3923
3924                 wfRunHooks( 'NewRevisionFromEditComplete',
3925                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
3926
3927                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
3928
3929                 if ( !$moveOverRedirect ) {
3930                         WikiPage::onArticleCreate( $nt );
3931                 }
3932
3933                 # Recreate the redirect, this time in the other direction.
3934                 if ( $redirectContent ) {
3935                         $redirectArticle = WikiPage::factory( $this );
3936                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
3937                         $newid = $redirectArticle->insertOn( $dbw );
3938                         if ( $newid ) { // sanity
3939                                 $this->resetArticleID( $newid );
3940                                 $redirectRevision = new Revision( array(
3941                                         'title' => $this, // for determining the default content model
3942                                         'page' => $newid,
3943                                         'comment' => $comment,
3944                                         'content' => $redirectContent ) );
3945                                 $redirectRevision->insertOn( $dbw );
3946                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
3947
3948                                 wfRunHooks( 'NewRevisionFromEditComplete',
3949                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
3950
3951                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
3952                         }
3953                 }
3954
3955                 # Log the move
3956                 $logid = $logEntry->insert();
3957                 $logEntry->publish( $logid );
3958         }
3959
3960         /**
3961          * Move this page's subpages to be subpages of $nt
3962          *
3963          * @param $nt Title Move target
3964          * @param bool $auth Whether $wgUser's permissions should be checked
3965          * @param string $reason The reason for the move
3966          * @param bool $createRedirect Whether to create redirects from the old subpages to
3967          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3968          * @return mixed array with old page titles as keys, and strings (new page titles) or
3969          *     arrays (errors) as values, or an error array with numeric indices if no pages
3970          *     were moved
3971          */
3972         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3973                 global $wgMaximumMovedPages;
3974                 // Check permissions
3975                 if ( !$this->userCan( 'move-subpages' ) ) {
3976                         return array( 'cant-move-subpages' );
3977                 }
3978                 // Do the source and target namespaces support subpages?
3979                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3980                         return array( 'namespace-nosubpages',
3981                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3982                 }
3983                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3984                         return array( 'namespace-nosubpages',
3985                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3986                 }
3987
3988                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3989                 $retval = array();
3990                 $count = 0;
3991                 foreach ( $subpages as $oldSubpage ) {
3992                         $count++;
3993                         if ( $count > $wgMaximumMovedPages ) {
3994                                 $retval[$oldSubpage->getPrefixedTitle()] =
3995                                                 array( 'movepage-max-pages',
3996                                                         $wgMaximumMovedPages );
3997                                 break;
3998                         }
3999
4000                         // We don't know whether this function was called before
4001                         // or after moving the root page, so check both
4002                         // $this and $nt
4003                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
4004                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
4005                         ) {
4006                                 // When moving a page to a subpage of itself,
4007                                 // don't move it twice
4008                                 continue;
4009                         }
4010                         $newPageName = preg_replace(
4011                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4012                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4013                                         $oldSubpage->getDBkey() );
4014                         if ( $oldSubpage->isTalkPage() ) {
4015                                 $newNs = $nt->getTalkPage()->getNamespace();
4016                         } else {
4017                                 $newNs = $nt->getSubjectPage()->getNamespace();
4018                         }
4019                         # Bug 14385: we need makeTitleSafe because the new page names may
4020                         # be longer than 255 characters.
4021                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4022
4023                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4024                         if ( $success === true ) {
4025                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4026                         } else {
4027                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4028                         }
4029                 }
4030                 return $retval;
4031         }
4032
4033         /**
4034          * Checks if this page is just a one-rev redirect.
4035          * Adds lock, so don't use just for light purposes.
4036          *
4037          * @return Bool
4038          */
4039         public function isSingleRevRedirect() {
4040                 global $wgContentHandlerUseDB;
4041
4042                 $dbw = wfGetDB( DB_MASTER );
4043
4044                 # Is it a redirect?
4045                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4046                 if ( $wgContentHandlerUseDB ) {
4047                         $fields[] = 'page_content_model';
4048                 }
4049
4050                 $row = $dbw->selectRow( 'page',
4051                         $fields,
4052                         $this->pageCond(),
4053                         __METHOD__,
4054                         array( 'FOR UPDATE' )
4055                 );
4056                 # Cache some fields we may want
4057                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4058                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4059                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4060                 $this->mContentModel = $row && isset( $row->page_content_model ) ? strval( $row->page_content_model ) : false;
4061                 if ( !$this->mRedirect ) {
4062                         return false;
4063                 }
4064                 # Does the article have a history?
4065                 $row = $dbw->selectField( array( 'page', 'revision' ),
4066                         'rev_id',
4067                         array( 'page_namespace' => $this->getNamespace(),
4068                                 'page_title' => $this->getDBkey(),
4069                                 'page_id=rev_page',
4070                                 'page_latest != rev_id'
4071                         ),
4072                         __METHOD__,
4073                         array( 'FOR UPDATE' )
4074                 );
4075                 # Return true if there was no history
4076                 return ( $row === false );
4077         }
4078
4079         /**
4080          * Checks if $this can be moved to a given Title
4081          * - Selects for update, so don't call it unless you mean business
4082          *
4083          * @param $nt Title the new title to check
4084          * @return Bool
4085          */
4086         public function isValidMoveTarget( $nt ) {
4087                 # Is it an existing file?
4088                 if ( $nt->getNamespace() == NS_FILE ) {
4089                         $file = wfLocalFile( $nt );
4090                         if ( $file->exists() ) {
4091                                 wfDebug( __METHOD__ . ": file exists\n" );
4092                                 return false;
4093                         }
4094                 }
4095                 # Is it a redirect with no history?
4096                 if ( !$nt->isSingleRevRedirect() ) {
4097                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4098                         return false;
4099                 }
4100                 # Get the article text
4101                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4102                 if ( !is_object( $rev ) ) {
4103                         return false;
4104                 }
4105                 $content = $rev->getContent();
4106                 # Does the redirect point to the source?
4107                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4108                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4109
4110                 if ( $redirTitle ) {
4111                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4112                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4113                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4114                                 return false;
4115                         } else {
4116                                 return true;
4117                         }
4118                 } else {
4119                         # Fail safe (not a redirect after all. strange.)
4120                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4121                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4122                         return false;
4123                 }
4124         }
4125
4126         /**
4127          * Get categories to which this Title belongs and return an array of
4128          * categories' names.
4129          *
4130          * @return Array of parents in the form:
4131          *        $parent => $currentarticle
4132          */
4133         public function getParentCategories() {
4134                 global $wgContLang;
4135
4136                 $data = array();
4137
4138                 $titleKey = $this->getArticleID();
4139
4140                 if ( $titleKey === 0 ) {
4141                         return $data;
4142                 }
4143
4144                 $dbr = wfGetDB( DB_SLAVE );
4145
4146                 $res = $dbr->select(
4147                         'categorylinks',
4148                         'cl_to',
4149                         array( 'cl_from' => $titleKey ),
4150                         __METHOD__
4151                 );
4152
4153                 if ( $res->numRows() > 0 ) {
4154                         foreach ( $res as $row ) {
4155                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4156                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4157                         }
4158                 }
4159                 return $data;
4160         }
4161
4162         /**
4163          * Get a tree of parent categories
4164          *
4165          * @param array $children with the children in the keys, to check for circular refs
4166          * @return Array Tree of parent categories
4167          */
4168         public function getParentCategoryTree( $children = array() ) {
4169                 $stack = array();
4170                 $parents = $this->getParentCategories();
4171
4172                 if ( $parents ) {
4173                         foreach ( $parents as $parent => $current ) {
4174                                 if ( array_key_exists( $parent, $children ) ) {
4175                                         # Circular reference
4176                                         $stack[$parent] = array();
4177                                 } else {
4178                                         $nt = Title::newFromText( $parent );
4179                                         if ( $nt ) {
4180                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4181                                         }
4182                                 }
4183                         }
4184                 }
4185
4186                 return $stack;
4187         }
4188
4189         /**
4190          * Get an associative array for selecting this title from
4191          * the "page" table
4192          *
4193          * @return Array suitable for the $where parameter of DB::select()
4194          */
4195         public function pageCond() {
4196                 if ( $this->mArticleID > 0 ) {
4197                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4198                         return array( 'page_id' => $this->mArticleID );
4199                 } else {
4200                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4201                 }
4202         }
4203
4204         /**
4205          * Get the revision ID of the previous revision
4206          *
4207          * @param int $revId Revision ID. Get the revision that was before this one.
4208          * @param int $flags Title::GAID_FOR_UPDATE
4209          * @return Int|Bool Old revision ID, or FALSE if none exists
4210          */
4211         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4212                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4213                 $revId = $db->selectField( 'revision', 'rev_id',
4214                         array(
4215                                 'rev_page' => $this->getArticleID( $flags ),
4216                                 'rev_id < ' . intval( $revId )
4217                         ),
4218                         __METHOD__,
4219                         array( 'ORDER BY' => 'rev_id DESC' )
4220                 );
4221
4222                 if ( $revId === false ) {
4223                         return false;
4224                 } else {
4225                         return intval( $revId );
4226                 }
4227         }
4228
4229         /**
4230          * Get the revision ID of the next revision
4231          *
4232          * @param int $revId Revision ID. Get the revision that was after this one.
4233          * @param int $flags Title::GAID_FOR_UPDATE
4234          * @return Int|Bool Next revision ID, or FALSE if none exists
4235          */
4236         public function getNextRevisionID( $revId, $flags = 0 ) {
4237                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4238                 $revId = $db->selectField( 'revision', 'rev_id',
4239                         array(
4240                                 'rev_page' => $this->getArticleID( $flags ),
4241                                 'rev_id > ' . intval( $revId )
4242                         ),
4243                         __METHOD__,
4244                         array( 'ORDER BY' => 'rev_id' )
4245                 );
4246
4247                 if ( $revId === false ) {
4248                         return false;
4249                 } else {
4250                         return intval( $revId );
4251                 }
4252         }
4253
4254         /**
4255          * Get the first revision of the page
4256          *
4257          * @param int $flags Title::GAID_FOR_UPDATE
4258          * @return Revision|Null if page doesn't exist
4259          */
4260         public function getFirstRevision( $flags = 0 ) {
4261                 $pageId = $this->getArticleID( $flags );
4262                 if ( $pageId ) {
4263                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4264                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4265                                 array( 'rev_page' => $pageId ),
4266                                 __METHOD__,
4267                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4268                         );
4269                         if ( $row ) {
4270                                 return new Revision( $row );
4271                         }
4272                 }
4273                 return null;
4274         }
4275
4276         /**
4277          * Get the oldest revision timestamp of this page
4278          *
4279          * @param int $flags Title::GAID_FOR_UPDATE
4280          * @return String: MW timestamp
4281          */
4282         public function getEarliestRevTime( $flags = 0 ) {
4283                 $rev = $this->getFirstRevision( $flags );
4284                 return $rev ? $rev->getTimestamp() : null;
4285         }
4286
4287         /**
4288          * Check if this is a new page
4289          *
4290          * @return bool
4291          */
4292         public function isNewPage() {
4293                 $dbr = wfGetDB( DB_SLAVE );
4294                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4295         }
4296
4297         /**
4298          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4299          *
4300          * @return bool
4301          */
4302         public function isBigDeletion() {
4303                 global $wgDeleteRevisionsLimit;
4304
4305                 if ( !$wgDeleteRevisionsLimit ) {
4306                         return false;
4307                 }
4308
4309                 $revCount = $this->estimateRevisionCount();
4310                 return $revCount > $wgDeleteRevisionsLimit;
4311         }
4312
4313         /**
4314          * Get the  approximate revision count of this page.
4315          *
4316          * @return int
4317          */
4318         public function estimateRevisionCount() {
4319                 if ( !$this->exists() ) {
4320                         return 0;
4321                 }
4322
4323                 if ( $this->mEstimateRevisions === null ) {
4324                         $dbr = wfGetDB( DB_SLAVE );
4325                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4326                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4327                 }
4328
4329                 return $this->mEstimateRevisions;
4330         }
4331
4332         /**
4333          * Get the number of revisions between the given revision.
4334          * Used for diffs and other things that really need it.
4335          *
4336          * @param int|Revision $old Old revision or rev ID (first before range)
4337          * @param int|Revision $new New revision or rev ID (first after range)
4338          * @return Int Number of revisions between these revisions.
4339          */
4340         public function countRevisionsBetween( $old, $new ) {
4341                 if ( !( $old instanceof Revision ) ) {
4342                         $old = Revision::newFromTitle( $this, (int)$old );
4343                 }
4344                 if ( !( $new instanceof Revision ) ) {
4345                         $new = Revision::newFromTitle( $this, (int)$new );
4346                 }
4347                 if ( !$old || !$new ) {
4348                         return 0; // nothing to compare
4349                 }
4350                 $dbr = wfGetDB( DB_SLAVE );
4351                 return (int)$dbr->selectField( 'revision', 'count(*)',
4352                         array(
4353                                 'rev_page' => $this->getArticleID(),
4354                                 'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4355                                 'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4356                         ),
4357                         __METHOD__
4358                 );
4359         }
4360
4361         /**
4362          * Get the number of authors between the given revisions or revision IDs.
4363          * Used for diffs and other things that really need it.
4364          *
4365          * @param int|Revision $old Old revision or rev ID (first before range by default)
4366          * @param int|Revision $new New revision or rev ID (first after range by default)
4367          * @param int $limit Maximum number of authors
4368          * @param string|array $options (Optional): Single option, or an array of options:
4369          *     'include_old' Include $old in the range; $new is excluded.
4370          *     'include_new' Include $new in the range; $old is excluded.
4371          *     'include_both' Include both $old and $new in the range.
4372          *     Unknown option values are ignored.
4373          * @return int Number of revision authors in the range; zero if not both revisions exist
4374          */
4375         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4376                 if ( !( $old instanceof Revision ) ) {
4377                         $old = Revision::newFromTitle( $this, (int)$old );
4378                 }
4379                 if ( !( $new instanceof Revision ) ) {
4380                         $new = Revision::newFromTitle( $this, (int)$new );
4381                 }
4382                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4383                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4384                 // in the sanity check below?
4385                 if ( !$old || !$new ) {
4386                         return 0; // nothing to compare
4387                 }
4388                 $old_cmp = '>';
4389                 $new_cmp = '<';
4390                 $options = (array)$options;
4391                 if ( in_array( 'include_old', $options ) ) {
4392                         $old_cmp = '>=';
4393                 }
4394                 if ( in_array( 'include_new', $options ) ) {
4395                         $new_cmp = '<=';
4396                 }
4397                 if ( in_array( 'include_both', $options ) ) {
4398                         $old_cmp = '>=';
4399                         $new_cmp = '<=';
4400                 }
4401                 // No DB query needed if $old and $new are the same or successive revisions:
4402                 if ( $old->getId() === $new->getId() ) {
4403                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4404                 } elseif ( $old->getId() === $new->getParentId() ) {
4405                         if ( $old_cmp === '>' || $new_cmp === '<' ) {
4406                                 return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4407                         }
4408                         return ( $old->getRawUserText() === $new->getRawUserText() ) ? 1 : 2;
4409                 }
4410                 $dbr = wfGetDB( DB_SLAVE );
4411                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4412                         array(
4413                                 'rev_page' => $this->getArticleID(),
4414                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4415                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4416                         ), __METHOD__,
4417                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4418                 );
4419                 return (int)$dbr->numRows( $res );
4420         }
4421
4422         /**
4423          * Compare with another title.
4424          *
4425          * @param $title Title
4426          * @return Bool
4427          */
4428         public function equals( Title $title ) {
4429                 // Note: === is necessary for proper matching of number-like titles.
4430                 return $this->getInterwiki() === $title->getInterwiki()
4431                         && $this->getNamespace() == $title->getNamespace()
4432                         && $this->getDBkey() === $title->getDBkey();
4433         }
4434
4435         /**
4436          * Check if this title is a subpage of another title
4437          *
4438          * @param $title Title
4439          * @return Bool
4440          */
4441         public function isSubpageOf( Title $title ) {
4442                 return $this->getInterwiki() === $title->getInterwiki()
4443                         && $this->getNamespace() == $title->getNamespace()
4444                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4445         }
4446
4447         /**
4448          * Check if page exists.  For historical reasons, this function simply
4449          * checks for the existence of the title in the page table, and will
4450          * thus return false for interwiki links, special pages and the like.
4451          * If you want to know if a title can be meaningfully viewed, you should
4452          * probably call the isKnown() method instead.
4453          *
4454          * @return Bool
4455          */
4456         public function exists() {
4457                 return $this->getArticleID() != 0;
4458         }
4459
4460         /**
4461          * Should links to this title be shown as potentially viewable (i.e. as
4462          * "bluelinks"), even if there's no record by this title in the page
4463          * table?
4464          *
4465          * This function is semi-deprecated for public use, as well as somewhat
4466          * misleadingly named.  You probably just want to call isKnown(), which
4467          * calls this function internally.
4468          *
4469          * (ISSUE: Most of these checks are cheap, but the file existence check
4470          * can potentially be quite expensive.  Including it here fixes a lot of
4471          * existing code, but we might want to add an optional parameter to skip
4472          * it and any other expensive checks.)
4473          *
4474          * @return Bool
4475          */
4476         public function isAlwaysKnown() {
4477                 $isKnown = null;
4478
4479                 /**
4480                  * Allows overriding default behavior for determining if a page exists.
4481                  * If $isKnown is kept as null, regular checks happen. If it's
4482                  * a boolean, this value is returned by the isKnown method.
4483                  *
4484                  * @since 1.20
4485                  *
4486                  * @param Title $title
4487                  * @param boolean|null $isKnown
4488                  */
4489                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4490
4491                 if ( !is_null( $isKnown ) ) {
4492                         return $isKnown;
4493                 }
4494
4495                 if ( $this->mInterwiki != '' ) {
4496                         return true;  // any interwiki link might be viewable, for all we know
4497                 }
4498
4499                 switch ( $this->mNamespace ) {
4500                         case NS_MEDIA:
4501                         case NS_FILE:
4502                                 // file exists, possibly in a foreign repo
4503                                 return (bool)wfFindFile( $this );
4504                         case NS_SPECIAL:
4505                                 // valid special page
4506                                 return SpecialPageFactory::exists( $this->getDBkey() );
4507                         case NS_MAIN:
4508                                 // selflink, possibly with fragment
4509                                 return $this->mDbkeyform == '';
4510                         case NS_MEDIAWIKI:
4511                                 // known system message
4512                                 return $this->hasSourceText() !== false;
4513                         default:
4514                                 return false;
4515                 }
4516         }
4517
4518         /**
4519          * Does this title refer to a page that can (or might) be meaningfully
4520          * viewed?  In particular, this function may be used to determine if
4521          * links to the title should be rendered as "bluelinks" (as opposed to
4522          * "redlinks" to non-existent pages).
4523          * Adding something else to this function will cause inconsistency
4524          * since LinkHolderArray calls isAlwaysKnown() and does its own
4525          * page existence check.
4526          *
4527          * @return Bool
4528          */
4529         public function isKnown() {
4530                 return $this->isAlwaysKnown() || $this->exists();
4531         }
4532
4533         /**
4534          * Does this page have source text?
4535          *
4536          * @return Boolean
4537          */
4538         public function hasSourceText() {
4539                 if ( $this->exists() ) {
4540                         return true;
4541                 }
4542
4543                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4544                         // If the page doesn't exist but is a known system message, default
4545                         // message content will be displayed, same for language subpages-
4546                         // Use always content language to avoid loading hundreds of languages
4547                         // to get the link color.
4548                         global $wgContLang;
4549                         list( $name, ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4550                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4551                         return $message->exists();
4552                 }
4553
4554                 return false;
4555         }
4556
4557         /**
4558          * Get the default message text or false if the message doesn't exist
4559          *
4560          * @return String or false
4561          */
4562         public function getDefaultMessageText() {
4563                 global $wgContLang;
4564
4565                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4566                         return false;
4567                 }
4568
4569                 list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4570                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4571
4572                 if ( $message->exists() ) {
4573                         return $message->plain();
4574                 } else {
4575                         return false;
4576                 }
4577         }
4578
4579         /**
4580          * Updates page_touched for this page; called from LinksUpdate.php
4581          *
4582          * @return Bool true if the update succeeded
4583          */
4584         public function invalidateCache() {
4585                 if ( wfReadOnly() ) {
4586                         return false;
4587                 }
4588
4589                 $method = __METHOD__;
4590                 $dbw = wfGetDB( DB_MASTER );
4591                 $conds = $this->pageCond();
4592                 $dbw->onTransactionIdle( function() use ( $dbw, $conds, $method ) {
4593                         $dbw->update(
4594                                 'page',
4595                                 array( 'page_touched' => $dbw->timestamp() ),
4596                                 $conds,
4597                                 $method
4598                         );
4599                 } );
4600
4601                 return true;
4602         }
4603
4604         /**
4605          * Update page_touched timestamps and send squid purge messages for
4606          * pages linking to this title. May be sent to the job queue depending
4607          * on the number of links. Typically called on create and delete.
4608          */
4609         public function touchLinks() {
4610                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4611                 $u->doUpdate();
4612
4613                 if ( $this->getNamespace() == NS_CATEGORY ) {
4614                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4615                         $u->doUpdate();
4616                 }
4617         }
4618
4619         /**
4620          * Get the last touched timestamp
4621          *
4622          * @param $db DatabaseBase: optional db
4623          * @return String last-touched timestamp
4624          */
4625         public function getTouched( $db = null ) {
4626                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
4627                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4628                 return $touched;
4629         }
4630
4631         /**
4632          * Get the timestamp when this page was updated since the user last saw it.
4633          *
4634          * @param $user User
4635          * @return String|Null
4636          */
4637         public function getNotificationTimestamp( $user = null ) {
4638                 global $wgUser, $wgShowUpdatedMarker;
4639                 // Assume current user if none given
4640                 if ( !$user ) {
4641                         $user = $wgUser;
4642                 }
4643                 // Check cache first
4644                 $uid = $user->getId();
4645                 // avoid isset here, as it'll return false for null entries
4646                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4647                         return $this->mNotificationTimestamp[$uid];
4648                 }
4649                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4650                         return $this->mNotificationTimestamp[$uid] = false;
4651                 }
4652                 // Don't cache too much!
4653                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4654                         $this->mNotificationTimestamp = array();
4655                 }
4656                 $dbr = wfGetDB( DB_SLAVE );
4657                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4658                         'wl_notificationtimestamp',
4659                         array(
4660                                 'wl_user' => $user->getId(),
4661                                 'wl_namespace' => $this->getNamespace(),
4662                                 'wl_title' => $this->getDBkey(),
4663                         ),
4664                         __METHOD__
4665                 );
4666                 return $this->mNotificationTimestamp[$uid];
4667         }
4668
4669         /**
4670          * Generate strings used for xml 'id' names in monobook tabs
4671          *
4672          * @param string $prepend defaults to 'nstab-'
4673          * @return String XML 'id' name
4674          */
4675         public function getNamespaceKey( $prepend = 'nstab-' ) {
4676                 global $wgContLang;
4677                 // Gets the subject namespace if this title
4678                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4679                 // Checks if canonical namespace name exists for namespace
4680                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4681                         // Uses canonical namespace name
4682                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4683                 } else {
4684                         // Uses text of namespace
4685                         $namespaceKey = $this->getSubjectNsText();
4686                 }
4687                 // Makes namespace key lowercase
4688                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4689                 // Uses main
4690                 if ( $namespaceKey == '' ) {
4691                         $namespaceKey = 'main';
4692                 }
4693                 // Changes file to image for backwards compatibility
4694                 if ( $namespaceKey == 'file' ) {
4695                         $namespaceKey = 'image';
4696                 }
4697                 return $prepend . $namespaceKey;
4698         }
4699
4700         /**
4701          * Get all extant redirects to this Title
4702          *
4703          * @param int|Null $ns Single namespace to consider; NULL to consider all namespaces
4704          * @return Title[] Array of Title redirects to this title
4705          */
4706         public function getRedirectsHere( $ns = null ) {
4707                 $redirs = array();
4708
4709                 $dbr = wfGetDB( DB_SLAVE );
4710                 $where = array(
4711                         'rd_namespace' => $this->getNamespace(),
4712                         'rd_title' => $this->getDBkey(),
4713                         'rd_from = page_id'
4714                 );
4715                 if ( $this->isExternal() ) {
4716                         $where['rd_interwiki'] = $this->getInterwiki();
4717                 } else {
4718                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4719                 }
4720                 if ( !is_null( $ns ) ) {
4721                         $where['page_namespace'] = $ns;
4722                 }
4723
4724                 $res = $dbr->select(
4725                         array( 'redirect', 'page' ),
4726                         array( 'page_namespace', 'page_title' ),
4727                         $where,
4728                         __METHOD__
4729                 );
4730
4731                 foreach ( $res as $row ) {
4732                         $redirs[] = self::newFromRow( $row );
4733                 }
4734                 return $redirs;
4735         }
4736
4737         /**
4738          * Check if this Title is a valid redirect target
4739          *
4740          * @return Bool
4741          */
4742         public function isValidRedirectTarget() {
4743                 global $wgInvalidRedirectTargets;
4744
4745                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4746                 if ( $this->isSpecial( 'Userlogout' ) ) {
4747                         return false;
4748                 }
4749
4750                 foreach ( $wgInvalidRedirectTargets as $target ) {
4751                         if ( $this->isSpecial( $target ) ) {
4752                                 return false;
4753                         }
4754                 }
4755
4756                 return true;
4757         }
4758
4759         /**
4760          * Get a backlink cache object
4761          *
4762          * @return BacklinkCache
4763          */
4764         public function getBacklinkCache() {
4765                 return BacklinkCache::get( $this );
4766         }
4767
4768         /**
4769          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4770          *
4771          * @return Boolean
4772          */
4773         public function canUseNoindex() {
4774                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4775
4776                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4777                         ? $wgContentNamespaces
4778                         : $wgExemptFromUserRobotsControl;
4779
4780                 return !in_array( $this->mNamespace, $bannedNamespaces );
4781
4782         }
4783
4784         /**
4785          * Returns the raw sort key to be used for categories, with the specified
4786          * prefix.  This will be fed to Collation::getSortKey() to get a
4787          * binary sortkey that can be used for actual sorting.
4788          *
4789          * @param string $prefix The prefix to be used, specified using
4790          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4791          *   prefix.
4792          * @return string
4793          */
4794         public function getCategorySortkey( $prefix = '' ) {
4795                 $unprefixed = $this->getText();
4796
4797                 // Anything that uses this hook should only depend
4798                 // on the Title object passed in, and should probably
4799                 // tell the users to run updateCollations.php --force
4800                 // in order to re-sort existing category relations.
4801                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4802                 if ( $prefix !== '' ) {
4803                         # Separate with a line feed, so the unprefixed part is only used as
4804                         # a tiebreaker when two pages have the exact same prefix.
4805                         # In UCA, tab is the only character that can sort above LF
4806                         # so we strip both of them from the original prefix.
4807                         $prefix = strtr( $prefix, "\n\t", '  ' );
4808                         return "$prefix\n$unprefixed";
4809                 }
4810                 return $unprefixed;
4811         }
4812
4813         /**
4814          * Get the language in which the content of this page is written in
4815          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4816          * e.g. $wgLang (such as special pages, which are in the user language).
4817          *
4818          * @since 1.18
4819          * @return Language
4820          */
4821         public function getPageLanguage() {
4822                 global $wgLang, $wgLanguageCode;
4823                 wfProfileIn( __METHOD__ );
4824                 if ( $this->isSpecialPage() ) {
4825                         // special pages are in the user language
4826                         wfProfileOut( __METHOD__ );
4827                         return $wgLang;
4828                 }
4829
4830                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4831                         // Note that this may depend on user settings, so the cache should be only per-request.
4832                         // NOTE: ContentHandler::getPageLanguage() may need to load the content to determine the page language!
4833                         // Checking $wgLanguageCode hasn't changed for the benefit of unit tests.
4834                         $contentHandler = ContentHandler::getForTitle( $this );
4835                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4836                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4837                 } else {
4838                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4839                 }
4840                 wfProfileOut( __METHOD__ );
4841                 return $langObj;
4842         }
4843
4844         /**
4845          * Get the language in which the content of this page is written when
4846          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4847          * e.g. $wgLang (such as special pages, which are in the user language).
4848          *
4849          * @since 1.20
4850          * @return Language
4851          */
4852         public function getPageViewLanguage() {
4853                 global $wgLang;
4854
4855                 if ( $this->isSpecialPage() ) {
4856                         // If the user chooses a variant, the content is actually
4857                         // in a language whose code is the variant code.
4858                         $variant = $wgLang->getPreferredVariant();
4859                         if ( $wgLang->getCode() !== $variant ) {
4860                                 return Language::factory( $variant );
4861                         }
4862
4863                         return $wgLang;
4864                 }
4865
4866                 //NOTE: can't be cached persistently, depends on user settings
4867                 //NOTE: ContentHandler::getPageViewLanguage() may need to load the content to determine the page language!
4868                 $contentHandler = ContentHandler::getForTitle( $this );
4869                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4870                 return $pageLang;
4871         }
4872
4873         /**
4874          * Get a list of rendered edit notices for this page.
4875          *
4876          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4877          * they will already be wrapped in paragraphs.
4878          *
4879          * @since 1.21
4880          * @param int oldid Revision ID that's being edited
4881          * @return Array
4882          */
4883         public function getEditNotices( $oldid = 0 ) {
4884                 $notices = array();
4885
4886                 # Optional notices on a per-namespace and per-page basis
4887                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4888                 $editnotice_ns_message = wfMessage( $editnotice_ns );
4889                 if ( $editnotice_ns_message->exists() ) {
4890                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
4891                 }
4892                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4893                         $parts = explode( '/', $this->getDBkey() );
4894                         $editnotice_base = $editnotice_ns;
4895                         while ( count( $parts ) > 0 ) {
4896                                 $editnotice_base .= '-' . array_shift( $parts );
4897                                 $editnotice_base_msg = wfMessage( $editnotice_base );
4898                                 if ( $editnotice_base_msg->exists() ) {
4899                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
4900                                 }
4901                         }
4902                 } else {
4903                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
4904                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
4905                         $editnoticeMsg = wfMessage( $editnoticeText );
4906                         if ( $editnoticeMsg->exists() ) {
4907                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
4908                         }
4909                 }
4910
4911                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4912                 return $notices;
4913         }
4914 }