includes/Title.php

   1 <?php
   2 /**
   3  * Representation a title within %MediaWiki.
   4  *
   5  * See title.txt
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24
  25 /**
  26  * Represents a title within MediaWiki.
  27  * Optionally may contain an interwiki designation or namespace.
  28  * @note This class can fetch various kinds of data from the database;
  29  *       however, it does so inefficiently.
  30  *
  31  * @internal documentation reviewed 15 Mar 2010
  32  */
  33 class Title {
  34         /** @name Static cache variables */
  35         // @{
  36         static private $titleCache = array();
  37         // @}
  38
  39         /**
  40          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  41          * commonly used titles. On a batch operation this can become a memory leak
  42          * if not bounded. After hitting this many titles reset the cache.
  43          */
  44         const CACHE_MAX = 1000;
  45
  46         /**
  47          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  48          * to use the master DB
  49          */
  50         const GAID_FOR_UPDATE = 1;
  51
  52         /**
  53          * @name Private member variables
  54          * Please use the accessor functions instead.
  55          * @private
  56          */
  57         // @{
  58
  59         var $mTextform = '';              // /< Text form (spaces not underscores) of the main part
  60         var $mUrlform = '';               // /< URL-encoded form of the main part
  61         var $mDbkeyform = '';             // /< Main part with underscores
  62         var $mUserCaseDBKey;              // /< DB key with the initial letter in the case specified by the user
  63         var $mNamespace = NS_MAIN;        // /< Namespace index, i.e. one of the NS_xxxx constants
  64         var $mInterwiki = '';             // /< Interwiki prefix (or null string)
  65         var $mFragment;                   // /< Title fragment (i.e. the bit after the #)
  66         var $mArticleID = -1;             // /< Article ID, fetched from the link cache on demand
  67         var $mLatestID = false;           // /< ID of most recent revision
  68         var $mContentModel = false;       // /< ID of the page's content model, i.e. one of the CONTENT_MODEL_XXX constants
  69         private $mEstimateRevisions;      // /< Estimated number of revisions; null of not loaded
  70         var $mRestrictions = array();     // /< Array of groups allowed to edit this article
  71         var $mOldRestrictions = false;
  72         var $mCascadeRestriction;         ///< Cascade restrictions on this page to included templates and images?
  73         var $mCascadingRestrictions;      // Caching the results of getCascadeProtectionSources
  74         var $mRestrictionsExpiry = array(); ///< When do the restrictions on this page expire?
  75         var $mHasCascadingRestrictions;   ///< Are cascading restrictions in effect on this page?
  76         var $mCascadeSources;             ///< Where are the cascading restrictions coming from on this page?
  77         var $mRestrictionsLoaded = false; ///< Boolean for initialisation on demand
  78         var $mPrefixedText;               ///< Text form including namespace/interwiki, initialised on demand
  79         var $mTitleProtection;            ///< Cached value for getTitleProtection (create protection)
  80         # Don't change the following default, NS_MAIN is hardcoded in several
  81         # places.  See bug 696.
  82         var $mDefaultNamespace = NS_MAIN; // /< Namespace index when there is no namespace
  83                                                                           # Zero except in {{transclusion}} tags
  84         var $mWatched = null;             // /< Is $wgUser watching this page? null if unfilled, accessed through userIsWatching()
  85         var $mLength = -1;                // /< The page length, 0 for special pages
  86         var $mRedirect = null;            // /< Is the article at this title a redirect?
  87         var $mNotificationTimestamp = array(); // /< Associative array of user ID -> timestamp/false
  88         var $mHasSubpage;                 // /< Whether a page has any subpages
  89         // @}
  90
  91         /**
  92          * Constructor
  93          */
  94         /*protected*/ function __construct() { }
  95
  96         /**
  97          * Create a new Title from a prefixed DB key
  98          *
  99          * @param string $key the database key, which has underscores
 100          *      instead of spaces, possibly including namespace and
 101          *      interwiki prefixes
 102          * @return Title, or NULL on an error
 103          */
 104         public static function newFromDBkey( $key ) {
 105                 $t = new Title();
 106                 $t->mDbkeyform = $key;
 107                 if ( $t->secureAndSplit() ) {
 108                         return $t;
 109                 } else {
 110                         return null;
 111                 }
 112         }
 113
 114         /**
 115          * Create a new Title from text, such as what one would find in a link. De-
 116          * codes any HTML entities in the text.
 117          *
 118          * @param string $text the link text; spaces, prefixes, and an
 119          *   initial ':' indicating the main namespace are accepted.
 120          * @param int $defaultNamespace the namespace to use if none is specified
 121          *   by a prefix.  If you want to force a specific namespace even if
 122          *   $text might begin with a namespace prefix, use makeTitle() or
 123          *   makeTitleSafe().
 124          * @throws MWException
 125          * @return Title|null - Title or null on an error.
 126          */
 127         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 128                 if ( is_object( $text ) ) {
 129                         throw new MWException( 'Title::newFromText given an object' );
 130                 }
 131
 132                 /**
 133                  * Wiki pages often contain multiple links to the same page.
 134                  * Title normalization and parsing can become expensive on
 135                  * pages with many links, so we can save a little time by
 136                  * caching them.
 137                  *
 138                  * In theory these are value objects and won't get changed...
 139                  */
 140                 if ( $defaultNamespace == NS_MAIN && isset( Title::$titleCache[$text] ) ) {
 141                         return Title::$titleCache[$text];
 142                 }
 143
 144                 # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 145                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 146
 147                 $t = new Title();
 148                 $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
 149                 $t->mDefaultNamespace = $defaultNamespace;
 150
 151                 static $cachedcount = 0;
 152                 if ( $t->secureAndSplit() ) {
 153                         if ( $defaultNamespace == NS_MAIN ) {
 154                                 if ( $cachedcount >= self::CACHE_MAX ) {
 155                                         # Avoid memory leaks on mass operations...
 156                                         Title::$titleCache = array();
 157                                         $cachedcount = 0;
 158                                 }
 159                                 $cachedcount++;
 160                                 Title::$titleCache[$text] =& $t;
 161                         }
 162                         return $t;
 163                 } else {
 164                         $ret = null;
 165                         return $ret;
 166                 }
 167         }
 168
 169         /**
 170          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 171          *
 172          * Example of wrong and broken code:
 173          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 174          *
 175          * Example of right code:
 176          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 177          *
 178          * Create a new Title from URL-encoded text. Ensures that
 179          * the given title's length does not exceed the maximum.
 180          *
 181          * @param string $url the title, as might be taken from a URL
 182          * @return Title the new object, or NULL on an error
 183          */
 184         public static function newFromURL( $url ) {
 185                 $t = new Title();
 186
 187                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 188                 # but some URLs used it as a space replacement and they still come
 189                 # from some external search tools.
 190                 if ( strpos( self::legalChars(), '+' ) === false ) {
 191                         $url = str_replace( '+', ' ', $url );
 192                 }
 193
 194                 $t->mDbkeyform = str_replace( ' ', '_', $url );
 195                 if ( $t->secureAndSplit() ) {
 196                         return $t;
 197                 } else {
 198                         return null;
 199                 }
 200         }
 201
 202         /**
 203          * Returns a list of fields that are to be selected for initializing Title objects or LinkCache entries.
 204          * Uses $wgContentHandlerUseDB to determine whether to include page_content_model.
 205          *
 206          * @return array
 207          */
 208         protected static function getSelectFields() {
 209                 global $wgContentHandlerUseDB;
 210
 211                 $fields = array(
 212                         'page_namespace', 'page_title', 'page_id',
 213                         'page_len', 'page_is_redirect', 'page_latest',
 214                 );
 215
 216                 if ( $wgContentHandlerUseDB ) {
 217                         $fields[] = 'page_content_model';
 218                 }
 219
 220                 return $fields;
 221         }
 222
 223         /**
 224          * Create a new Title from an article ID
 225          *
 226          * @param int $id the page_id corresponding to the Title to create
 227          * @param int $flags use Title::GAID_FOR_UPDATE to use master
 228          * @return Title|null the new object, or NULL on an error
 229          */
 230         public static function newFromID( $id, $flags = 0 ) {
 231                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 232                 $row = $db->selectRow(
 233                         'page',
 234                         self::getSelectFields(),
 235                         array( 'page_id' => $id ),
 236                         __METHOD__
 237                 );
 238                 if ( $row !== false ) {
 239                         $title = Title::newFromRow( $row );
 240                 } else {
 241                         $title = null;
 242                 }
 243                 return $title;
 244         }
 245
 246         /**
 247          * Make an array of titles from an array of IDs
 248          *
 249          * @param array $ids of Int Array of IDs
 250          * @return Array of Titles
 251          */
 252         public static function newFromIDs( $ids ) {
 253                 if ( !count( $ids ) ) {
 254                         return array();
 255                 }
 256                 $dbr = wfGetDB( DB_SLAVE );
 257
 258                 $res = $dbr->select(
 259                         'page',
 260                         self::getSelectFields(),
 261                         array( 'page_id' => $ids ),
 262                         __METHOD__
 263                 );
 264
 265                 $titles = array();
 266                 foreach ( $res as $row ) {
 267                         $titles[] = Title::newFromRow( $row );
 268                 }
 269                 return $titles;
 270         }
 271
 272         /**
 273          * Make a Title object from a DB row
 274          *
 275          * @param $row Object database row (needs at least page_title,page_namespace)
 276          * @return Title corresponding Title
 277          */
 278         public static function newFromRow( $row ) {
 279                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 280                 $t->loadFromRow( $row );
 281                 return $t;
 282         }
 283
 284         /**
 285          * Load Title object fields from a DB row.
 286          * If false is given, the title will be treated as non-existing.
 287          *
 288          * @param $row Object|bool database row
 289          */
 290         public function loadFromRow( $row ) {
 291                 if ( $row ) { // page found
 292                         if ( isset( $row->page_id ) ) {
 293                                 $this->mArticleID = (int)$row->page_id;
 294                         }
 295                         if ( isset( $row->page_len ) ) {
 296                                 $this->mLength = (int)$row->page_len;
 297                         }
 298                         if ( isset( $row->page_is_redirect ) ) {
 299                                 $this->mRedirect = (bool)$row->page_is_redirect;
 300                         }
 301                         if ( isset( $row->page_latest ) ) {
 302                                 $this->mLatestID = (int)$row->page_latest;
 303                         }
 304                         if ( isset( $row->page_content_model ) ) {
 305                                 $this->mContentModel = strval( $row->page_content_model );
 306                         } else {
 307                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 308                         }
 309                 } else { // page not found
 310                         $this->mArticleID = 0;
 311                         $this->mLength = 0;
 312                         $this->mRedirect = false;
 313                         $this->mLatestID = 0;
 314                         $this->mContentModel = false; # initialized lazily in getContentModel()
 315                 }
 316         }
 317
 318         /**
 319          * Create a new Title from a namespace index and a DB key.
 320          * It's assumed that $ns and $title are *valid*, for instance when
 321          * they came directly from the database or a special page name.
 322          * For convenience, spaces are converted to underscores so that
 323          * eg user_text fields can be used directly.
 324          *
 325          * @param int $ns the namespace of the article
 326          * @param string $title the unprefixed database key form
 327          * @param string $fragment the link fragment (after the "#")
 328          * @param string $interwiki the interwiki prefix
 329          * @return Title the new object
 330          */
 331         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 332                 $t = new Title();
 333                 $t->mInterwiki = $interwiki;
 334                 $t->mFragment = $fragment;
 335                 $t->mNamespace = $ns = intval( $ns );
 336                 $t->mDbkeyform = str_replace( ' ', '_', $title );
 337                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 338                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 339                 $t->mTextform = str_replace( '_', ' ', $title );
 340                 $t->mContentModel = false; # initialized lazily in getContentModel()
 341                 return $t;
 342         }
 343
 344         /**
 345          * Create a new Title from a namespace index and a DB key.
 346          * The parameters will be checked for validity, which is a bit slower
 347          * than makeTitle() but safer for user-provided data.
 348          *
 349          * @param int $ns the namespace of the article
 350          * @param string $title database key form
 351          * @param string $fragment the link fragment (after the "#")
 352          * @param string $interwiki interwiki prefix
 353          * @return Title the new object, or NULL on an error
 354          */
 355         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 356                 if ( !MWNamespace::exists( $ns ) ) {
 357                         return null;
 358                 }
 359
 360                 $t = new Title();
 361                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
 362                 if ( $t->secureAndSplit() ) {
 363                         return $t;
 364                 } else {
 365                         return null;
 366                 }
 367         }
 368
 369         /**
 370          * Create a new Title for the Main Page
 371          *
 372          * @return Title the new object
 373          */
 374         public static function newMainPage() {
 375                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 376                 // Don't give fatal errors if the message is broken
 377                 if ( !$title ) {
 378                         $title = Title::newFromText( 'Main Page' );
 379                 }
 380                 return $title;
 381         }
 382
 383         /**
 384          * Extract a redirect destination from a string and return the
 385          * Title, or null if the text doesn't contain a valid redirect
 386          * This will only return the very next target, useful for
 387          * the redirect table and other checks that don't need full recursion
 388          *
 389          * @param string $text Text with possible redirect
 390          * @return Title: The corresponding Title
 391          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 392          */
 393         public static function newFromRedirect( $text ) {
 394                 ContentHandler::deprecated( __METHOD__, '1.21' );
 395
 396                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 397                 return $content->getRedirectTarget();
 398         }
 399
 400         /**
 401          * Extract a redirect destination from a string and return the
 402          * Title, or null if the text doesn't contain a valid redirect
 403          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 404          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 405          *
 406          * @param string $text Text with possible redirect
 407          * @return Title
 408          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 409          */
 410         public static function newFromRedirectRecurse( $text ) {
 411                 ContentHandler::deprecated( __METHOD__, '1.21' );
 412
 413                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 414                 return $content->getUltimateRedirectTarget();
 415         }
 416
 417         /**
 418          * Extract a redirect destination from a string and return an
 419          * array of Titles, or null if the text doesn't contain a valid redirect
 420          * The last element in the array is the final destination after all redirects
 421          * have been resolved (up to $wgMaxRedirects times)
 422          *
 423          * @param string $text Text with possible redirect
 424          * @return Array of Titles, with the destination last
 425          * @deprecated since 1.21, use Content::getRedirectChain instead.
 426          */
 427         public static function newFromRedirectArray( $text ) {
 428                 ContentHandler::deprecated( __METHOD__, '1.21' );
 429
 430                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 431                 return $content->getRedirectChain();
 432         }
 433
 434         /**
 435          * Get the prefixed DB key associated with an ID
 436          *
 437          * @param int $id the page_id of the article
 438          * @return Title an object representing the article, or NULL if no such article was found
 439          */
 440         public static function nameOf( $id ) {
 441                 $dbr = wfGetDB( DB_SLAVE );
 442
 443                 $s = $dbr->selectRow(
 444                         'page',
 445                         array( 'page_namespace', 'page_title' ),
 446                         array( 'page_id' => $id ),
 447                         __METHOD__
 448                 );
 449                 if ( $s === false ) {
 450                         return null;
 451                 }
 452
 453                 $n = self::makeName( $s->page_namespace, $s->page_title );
 454                 return $n;
 455         }
 456
 457         /**
 458          * Get a regex character class describing the legal characters in a link
 459          *
 460          * @return String the list of characters, not delimited
 461          */
 462         public static function legalChars() {
 463                 global $wgLegalTitleChars;
 464                 return $wgLegalTitleChars;
 465         }
 466
 467         /**
 468          * Returns a simple regex that will match on characters and sequences invalid in titles.
 469          * Note that this doesn't pick up many things that could be wrong with titles, but that
 470          * replacing this regex with something valid will make many titles valid.
 471          *
 472          * @return String regex string
 473          */
 474         static function getTitleInvalidRegex() {
 475                 static $rxTc = false;
 476                 if ( !$rxTc ) {
 477                         # Matching titles will be held as illegal.
 478                         $rxTc = '/' .
 479                                 # Any character not allowed is forbidden...
 480                                 '[^' . self::legalChars() . ']' .
 481                                 # URL percent encoding sequences interfere with the ability
 482                                 # to round-trip titles -- you can't link to them consistently.
 483                                 '|%[0-9A-Fa-f]{2}' .
 484                                 # XML/HTML character references produce similar issues.
 485                                 '|&[A-Za-z0-9\x80-\xff]+;' .
 486                                 '|&#[0-9]+;' .
 487                                 '|&#x[0-9A-Fa-f]+;' .
 488                                 '/S';
 489                 }
 490
 491                 return $rxTc;
 492         }
 493
 494         /**
 495          * Utility method for converting a character sequence from bytes to Unicode.
 496          *
 497          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 498          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 499          *
 500          * @param string $byteClass
 501          * @return string
 502          */
 503         public static function convertByteClassToUnicodeClass( $byteClass ) {
 504                 $length = strlen( $byteClass );
 505                 // Input token queue
 506                 $x0 = $x1 = $x2 = '';
 507                 // Decoded queue
 508                 $d0 = $d1 = $d2 = '';
 509                 // Decoded integer codepoints
 510                 $ord0 = $ord1 = $ord2 = 0;
 511                 // Re-encoded queue
 512                 $r0 = $r1 = $r2 = '';
 513                 // Output
 514                 $out = '';
 515                 // Flags
 516                 $allowUnicode = false;
 517                 for ( $pos = 0; $pos < $length; $pos++ ) {
 518                         // Shift the queues down
 519                         $x2 = $x1;
 520                         $x1 = $x0;
 521                         $d2 = $d1;
 522                         $d1 = $d0;
 523                         $ord2 = $ord1;
 524                         $ord1 = $ord0;
 525                         $r2 = $r1;
 526                         $r1 = $r0;
 527                         // Load the current input token and decoded values
 528                         $inChar = $byteClass[$pos];
 529                         if ( $inChar == '\\' ) {
 530                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 531                                         $x0 = $inChar . $m[0];
 532                                         $d0 = chr( hexdec( $m[1] ) );
 533                                         $pos += strlen( $m[0] );
 534                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 535                                         $x0 = $inChar . $m[0];
 536                                         $d0 = chr( octdec( $m[0] ) );
 537                                         $pos += strlen( $m[0] );
 538                                 } elseif ( $pos + 1 >= $length ) {
 539                                         $x0 = $d0 = '\\';
 540                                 } else {
 541                                         $d0 = $byteClass[$pos + 1];
 542                                         $x0 = $inChar . $d0;
 543                                         $pos += 1;
 544                                 }
 545                         } else {
 546                                 $x0 = $d0 = $inChar;
 547                         }
 548                         $ord0 = ord( $d0 );
 549                         // Load the current re-encoded value
 550                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 551                                 $r0 = sprintf( '\x%02x', $ord0 );
 552                         } elseif ( $ord0 >= 0x80 ) {
 553                                 // Allow unicode if a single high-bit character appears
 554                                 $r0 = sprintf( '\x%02x', $ord0 );
 555                                 $allowUnicode = true;
 556                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 557                                 $r0 = '\\' . $d0;
 558                         } else {
 559                                 $r0 = $d0;
 560                         }
 561                         // Do the output
 562                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 563                                 // Range
 564                                 if ( $ord2 > $ord0 ) {
 565                                         // Empty range
 566                                 } elseif ( $ord0 >= 0x80 ) {
 567                                         // Unicode range
 568                                         $allowUnicode = true;
 569                                         if ( $ord2 < 0x80 ) {
 570                                                 // Keep the non-unicode section of the range
 571                                                 $out .= "$r2-\\x7F";
 572                                         }
 573                                 } else {
 574                                         // Normal range
 575                                         $out .= "$r2-$r0";
 576                                 }
 577                                 // Reset state to the initial value
 578                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 579                         } elseif ( $ord2 < 0x80 ) {
 580                                 // ASCII character
 581                                 $out .= $r2;
 582                         }
 583                 }
 584                 if ( $ord1 < 0x80 ) {
 585                         $out .= $r1;
 586                 }
 587                 if ( $ord0 < 0x80 ) {
 588                         $out .= $r0;
 589                 }
 590                 if ( $allowUnicode ) {
 591                         $out .= '\u0080-\uFFFF';
 592                 }
 593                 return $out;
 594         }
 595
 596         /**
 597          * Get a string representation of a title suitable for
 598          * including in a search index
 599          *
 600          * @param int $ns a namespace index
 601          * @param string $title text-form main part
 602          * @return String a stripped-down title string ready for the search index
 603          */
 604         public static function indexTitle( $ns, $title ) {
 605                 global $wgContLang;
 606
 607                 $lc = SearchEngine::legalSearchChars() . '&#;';
 608                 $t = $wgContLang->normalizeForSearch( $title );
 609                 $t = preg_replace( "/[^{$lc}]+/", ' ', $t );
 610                 $t = $wgContLang->lc( $t );
 611
 612                 # Handle 's, s'
 613                 $t = preg_replace( "/([{$lc}]+)'s( |$)/", "\\1 \\1's ", $t );
 614                 $t = preg_replace( "/([{$lc}]+)s'( |$)/", "\\1s ", $t );
 615
 616                 $t = preg_replace( "/\\s+/", ' ', $t );
 617
 618                 if ( $ns == NS_FILE ) {
 619                         $t = preg_replace( "/ (png|gif|jpg|jpeg|ogg)$/", "", $t );
 620                 }
 621                 return trim( $t );
 622         }
 623
 624         /**
 625          * Make a prefixed DB key from a DB key and a namespace index
 626          *
 627          * @param int $ns numerical representation of the namespace
 628          * @param string $title the DB key form the title
 629          * @param string $fragment The link fragment (after the "#")
 630          * @param string $interwiki The interwiki prefix
 631          * @return String the prefixed form of the title
 632          */
 633         public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
 634                 global $wgContLang;
 635
 636                 $namespace = $wgContLang->getNsText( $ns );
 637                 $name = $namespace == '' ? $title : "$namespace:$title";
 638                 if ( strval( $interwiki ) != '' ) {
 639                         $name = "$interwiki:$name";
 640                 }
 641                 if ( strval( $fragment ) != '' ) {
 642                         $name .= '#' . $fragment;
 643                 }
 644                 return $name;
 645         }
 646
 647         /**
 648          * Escape a text fragment, say from a link, for a URL
 649          *
 650          * @param string $fragment containing a URL or link fragment (after the "#")
 651          * @return String: escaped string
 652          */
 653         static function escapeFragmentForURL( $fragment ) {
 654                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 655                 # fragments appear not to work in IE (at least up to 7) or in at least
 656                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 657                 # to care if they aren't encoded.
 658                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 659         }
 660
 661         /**
 662          * Callback for usort() to do title sorts by (namespace, title)
 663          *
 664          * @param $a Title
 665          * @param $b Title
 666          *
 667          * @return Integer: result of string comparison, or namespace comparison
 668          */
 669         public static function compare( $a, $b ) {
 670                 if ( $a->getNamespace() == $b->getNamespace() ) {
 671                         return strcmp( $a->getText(), $b->getText() );
 672                 } else {
 673                         return $a->getNamespace() - $b->getNamespace();
 674                 }
 675         }
 676
 677         /**
 678          * Determine whether the object refers to a page within
 679          * this project.
 680          *
 681          * @return Bool TRUE if this is an in-project interwiki link or a wikilink, FALSE otherwise
 682          */
 683         public function isLocal() {
 684                 if ( $this->mInterwiki != '' ) {
 685                         $iw = Interwiki::fetch( $this->mInterwiki );
 686                         if ( $iw ) {
 687                                 return $iw->isLocal();
 688                         }
 689                 }
 690                 return true;
 691         }
 692
 693         /**
 694          * Is this Title interwiki?
 695          *
 696          * @return Bool
 697          */
 698         public function isExternal() {
 699                 return ( $this->mInterwiki != '' );
 700         }
 701
 702         /**
 703          * Get the interwiki prefix (or null string)
 704          *
 705          * @return String Interwiki prefix
 706          */
 707         public function getInterwiki() {
 708                 return $this->mInterwiki;
 709         }
 710
 711         /**
 712          * Determine whether the object refers to a page within
 713          * this project and is transcludable.
 714          *
 715          * @return Bool TRUE if this is transcludable
 716          */
 717         public function isTrans() {
 718                 if ( $this->mInterwiki == '' ) {
 719                         return false;
 720                 }
 721
 722                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 723         }
 724
 725         /**
 726          * Returns the DB name of the distant wiki which owns the object.
 727          *
 728          * @return String the DB name
 729          */
 730         public function getTransWikiID() {
 731                 if ( $this->mInterwiki == '' ) {
 732                         return false;
 733                 }
 734
 735                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 736         }
 737
 738         /**
 739          * Get the text form (spaces not underscores) of the main part
 740          *
 741          * @return String Main part of the title
 742          */
 743         public function getText() {
 744                 return $this->mTextform;
 745         }
 746
 747         /**
 748          * Get the URL-encoded form of the main part
 749          *
 750          * @return String Main part of the title, URL-encoded
 751          */
 752         public function getPartialURL() {
 753                 return $this->mUrlform;
 754         }
 755
 756         /**
 757          * Get the main part with underscores
 758          *
 759          * @return String: Main part of the title, with underscores
 760          */
 761         public function getDBkey() {
 762                 return $this->mDbkeyform;
 763         }
 764
 765         /**
 766          * Get the DB key with the initial letter case as specified by the user
 767          *
 768          * @return String DB key
 769          */
 770         function getUserCaseDBKey() {
 771                 return $this->mUserCaseDBKey;
 772         }
 773
 774         /**
 775          * Get the namespace index, i.e. one of the NS_xxxx constants.
 776          *
 777          * @return Integer: Namespace index
 778          */
 779         public function getNamespace() {
 780                 return $this->mNamespace;
 781         }
 782
 783         /**
 784          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 785          *
 786          * @throws MWException
 787          * @return String: Content model id
 788          */
 789         public function getContentModel() {
 790                 if ( !$this->mContentModel ) {
 791                         $linkCache = LinkCache::singleton();
 792                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 793                 }
 794
 795                 if ( !$this->mContentModel ) {
 796                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 797                 }
 798
 799                 if ( !$this->mContentModel ) {
 800                         throw new MWException( 'Failed to determine content model!' );
 801                 }
 802
 803                 return $this->mContentModel;
 804         }
 805
 806         /**
 807          * Convenience method for checking a title's content model name
 808          *
 809          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 810          * @return Boolean true if $this->getContentModel() == $id
 811          */
 812         public function hasContentModel( $id ) {
 813                 return $this->getContentModel() == $id;
 814         }
 815
 816         /**
 817          * Get the namespace text
 818          *
 819          * @return String: Namespace text
 820          */
 821         public function getNsText() {
 822                 global $wgContLang;
 823
 824                 if ( $this->mInterwiki != '' ) {
 825                         // This probably shouldn't even happen. ohh man, oh yuck.
 826                         // But for interwiki transclusion it sometimes does.
 827                         // Shit. Shit shit shit.
 828                         //
 829                         // Use the canonical namespaces if possible to try to
 830                         // resolve a foreign namespace.
 831                         if ( MWNamespace::exists( $this->mNamespace ) ) {
 832                                 return MWNamespace::getCanonicalName( $this->mNamespace );
 833                         }
 834                 }
 835
 836                 if ( $wgContLang->needsGenderDistinction() &&
 837                                 MWNamespace::hasGenderDistinction( $this->mNamespace ) ) {
 838                         $gender = GenderCache::singleton()->getGenderOf( $this->getText(), __METHOD__ );
 839                         return $wgContLang->getGenderNsText( $this->mNamespace, $gender );
 840                 }
 841
 842                 return $wgContLang->getNsText( $this->mNamespace );
 843         }
 844
 845         /**
 846          * Get the namespace text of the subject (rather than talk) page
 847          *
 848          * @return String Namespace text
 849          */
 850         public function getSubjectNsText() {
 851                 global $wgContLang;
 852                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
 853         }
 854
 855         /**
 856          * Get the namespace text of the talk page
 857          *
 858          * @return String Namespace text
 859          */
 860         public function getTalkNsText() {
 861                 global $wgContLang;
 862                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
 863         }
 864
 865         /**
 866          * Could this title have a corresponding talk page?
 867          *
 868          * @return Bool TRUE or FALSE
 869          */
 870         public function canTalk() {
 871                 return MWNamespace::canTalk( $this->mNamespace );
 872         }
 873
 874         /**
 875          * Is this in a namespace that allows actual pages?
 876          *
 877          * @return Bool
 878          * @internal note -- uses hardcoded namespace index instead of constants
 879          */
 880         public function canExist() {
 881                 return $this->mNamespace >= NS_MAIN;
 882         }
 883
 884         /**
 885          * Can this title be added to a user's watchlist?
 886          *
 887          * @return Bool TRUE or FALSE
 888          */
 889         public function isWatchable() {
 890                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
 891         }
 892
 893         /**
 894          * Returns true if this is a special page.
 895          *
 896          * @return boolean
 897          */
 898         public function isSpecialPage() {
 899                 return $this->getNamespace() == NS_SPECIAL;
 900         }
 901
 902         /**
 903          * Returns true if this title resolves to the named special page
 904          *
 905          * @param string $name The special page name
 906          * @return boolean
 907          */
 908         public function isSpecial( $name ) {
 909                 if ( $this->isSpecialPage() ) {
 910                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
 911                         if ( $name == $thisName ) {
 912                                 return true;
 913                         }
 914                 }
 915                 return false;
 916         }
 917
 918         /**
 919          * If the Title refers to a special page alias which is not the local default, resolve
 920          * the alias, and localise the name as necessary.  Otherwise, return $this
 921          *
 922          * @return Title
 923          */
 924         public function fixSpecialName() {
 925                 if ( $this->isSpecialPage() ) {
 926                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
 927                         if ( $canonicalName ) {
 928                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
 929                                 if ( $localName != $this->mDbkeyform ) {
 930                                         return Title::makeTitle( NS_SPECIAL, $localName );
 931                                 }
 932                         }
 933                 }
 934                 return $this;
 935         }
 936
 937         /**
 938          * Returns true if the title is inside the specified namespace.
 939          *
 940          * Please make use of this instead of comparing to getNamespace()
 941          * This function is much more resistant to changes we may make
 942          * to namespaces than code that makes direct comparisons.
 943          * @param int $ns The namespace
 944          * @return bool
 945          * @since 1.19
 946          */
 947         public function inNamespace( $ns ) {
 948                 return MWNamespace::equals( $this->getNamespace(), $ns );
 949         }
 950
 951         /**
 952          * Returns true if the title is inside one of the specified namespaces.
 953          *
 954          * @param ...$namespaces The namespaces to check for
 955          * @return bool
 956          * @since 1.19
 957          */
 958         public function inNamespaces( /* ... */ ) {
 959                 $namespaces = func_get_args();
 960                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
 961                         $namespaces = $namespaces[0];
 962                 }
 963
 964                 foreach ( $namespaces as $ns ) {
 965                         if ( $this->inNamespace( $ns ) ) {
 966                                 return true;
 967                         }
 968                 }
 969
 970                 return false;
 971         }
 972
 973         /**
 974          * Returns true if the title has the same subject namespace as the
 975          * namespace specified.
 976          * For example this method will take NS_USER and return true if namespace
 977          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
 978          * as their subject namespace.
 979          *
 980          * This is MUCH simpler than individually testing for equivalence
 981          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
 982          * @since 1.19
 983          * @param $ns int
 984          * @return bool
 985          */
 986         public function hasSubjectNamespace( $ns ) {
 987                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
 988         }
 989
 990         /**
 991          * Is this Title in a namespace which contains content?
 992          * In other words, is this a content page, for the purposes of calculating
 993          * statistics, etc?
 994          *
 995          * @return Boolean
 996          */
 997         public function isContentPage() {
 998                 return MWNamespace::isContent( $this->getNamespace() );
 999         }
1000
1001         /**
1002          * Would anybody with sufficient privileges be able to move this page?
1003          * Some pages just aren't movable.
1004          *
1005          * @return Bool TRUE or FALSE
1006          */
1007         public function isMovable() {
1008                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->getInterwiki() != '' ) {
1009                         // Interwiki title or immovable namespace. Hooks don't get to override here
1010                         return false;
1011                 }
1012
1013                 $result = true;
1014                 wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
1015                 return $result;
1016         }
1017
1018         /**
1019          * Is this the mainpage?
1020          * @note Title::newFromText seems to be sufficiently optimized by the title
1021          * cache that we don't need to over-optimize by doing direct comparisons and
1022          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1023          * ends up reporting something differently than $title->isMainPage();
1024          *
1025          * @since 1.18
1026          * @return Bool
1027          */
1028         public function isMainPage() {
1029                 return $this->equals( Title::newMainPage() );
1030         }
1031
1032         /**
1033          * Is this a subpage?
1034          *
1035          * @return Bool
1036          */
1037         public function isSubpage() {
1038                 return MWNamespace::hasSubpages( $this->mNamespace )
1039                         ? strpos( $this->getText(), '/' ) !== false
1040                         : false;
1041         }
1042
1043         /**
1044          * Is this a conversion table for the LanguageConverter?
1045          *
1046          * @return Bool
1047          */
1048         public function isConversionTable() {
1049                 // @todo ConversionTable should become a separate content model.
1050
1051                 return $this->getNamespace() == NS_MEDIAWIKI &&
1052                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1053         }
1054
1055         /**
1056          * Does that page contain wikitext, or it is JS, CSS or whatever?
1057          *
1058          * @return Bool
1059          */
1060         public function isWikitextPage() {
1061                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1062         }
1063
1064         /**
1065          * Could this page contain custom CSS or JavaScript for the global UI.
1066          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1067          * or CONTENT_MODEL_JAVASCRIPT.
1068          *
1069          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage() for that!
1070          *
1071          * Note that this method should not return true for pages that contain and show "inactive" CSS or JS.
1072          *
1073          * @return Bool
1074          */
1075         public function isCssOrJsPage() {
1076                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1077                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1078                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1079
1080                 #NOTE: this hook is also called in ContentHandler::getDefaultModel. It's called here again to make sure
1081                 #      hook functions can force this method to return true even outside the mediawiki namespace.
1082
1083                 wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ) );
1084
1085                 return $isCssOrJsPage;
1086         }
1087
1088         /**
1089          * Is this a .css or .js subpage of a user page?
1090          * @return Bool
1091          */
1092         public function isCssJsSubpage() {
1093                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1094                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1095                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1096         }
1097
1098         /**
1099          * Trim down a .css or .js subpage title to get the corresponding skin name
1100          *
1101          * @return string containing skin name from .css or .js subpage title
1102          */
1103         public function getSkinFromCssJsSubpage() {
1104                 $subpage = explode( '/', $this->mTextform );
1105                 $subpage = $subpage[count( $subpage ) - 1];
1106                 $lastdot = strrpos( $subpage, '.' );
1107                 if ( $lastdot === false ) {
1108                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1109                 }
1110                 return substr( $subpage, 0, $lastdot );
1111         }
1112
1113         /**
1114          * Is this a .css subpage of a user page?
1115          *
1116          * @return Bool
1117          */
1118         public function isCssSubpage() {
1119                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1120                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1121         }
1122
1123         /**
1124          * Is this a .js subpage of a user page?
1125          *
1126          * @return Bool
1127          */
1128         public function isJsSubpage() {
1129                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1130                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1131         }
1132
1133         /**
1134          * Is this a talk page of some sort?
1135          *
1136          * @return Bool
1137          */
1138         public function isTalkPage() {
1139                 return MWNamespace::isTalk( $this->getNamespace() );
1140         }
1141
1142         /**
1143          * Get a Title object associated with the talk page of this article
1144          *
1145          * @return Title the object for the talk page
1146          */
1147         public function getTalkPage() {
1148                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1149         }
1150
1151         /**
1152          * Get a title object associated with the subject page of this
1153          * talk page
1154          *
1155          * @return Title the object for the subject page
1156          */
1157         public function getSubjectPage() {
1158                 // Is this the same title?
1159                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1160                 if ( $this->getNamespace() == $subjectNS ) {
1161                         return $this;
1162                 }
1163                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1164         }
1165
1166         /**
1167          * Get the default namespace index, for when there is no namespace
1168          *
1169          * @return Int Default namespace index
1170          */
1171         public function getDefaultNamespace() {
1172                 return $this->mDefaultNamespace;
1173         }
1174
1175         /**
1176          * Get title for search index
1177          *
1178          * @return String a stripped-down title string ready for the
1179          *  search index
1180          */
1181         public function getIndexTitle() {
1182                 return Title::indexTitle( $this->mNamespace, $this->mTextform );
1183         }
1184
1185         /**
1186          * Get the Title fragment (i.e.\ the bit after the #) in text form
1187          *
1188          * @return String Title fragment
1189          */
1190         public function getFragment() {
1191                 return $this->mFragment;
1192         }
1193
1194         /**
1195          * Get the fragment in URL form, including the "#" character if there is one
1196          * @return String Fragment in URL form
1197          */
1198         public function getFragmentForURL() {
1199                 if ( $this->mFragment == '' ) {
1200                         return '';
1201                 } else {
1202                         return '#' . Title::escapeFragmentForURL( $this->mFragment );
1203                 }
1204         }
1205
1206         /**
1207          * Set the fragment for this title. Removes the first character from the
1208          * specified fragment before setting, so it assumes you're passing it with
1209          * an initial "#".
1210          *
1211          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1212          * Still in active use privately.
1213          *
1214          * @param string $fragment text
1215          */
1216         public function setFragment( $fragment ) {
1217                 $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
1218         }
1219
1220         /**
1221          * Prefix some arbitrary text with the namespace or interwiki prefix
1222          * of this object
1223          *
1224          * @param string $name the text
1225          * @return String the prefixed text
1226          * @private
1227          */
1228         private function prefix( $name ) {
1229                 $p = '';
1230                 if ( $this->mInterwiki != '' ) {
1231                         $p = $this->mInterwiki . ':';
1232                 }
1233
1234                 if ( 0 != $this->mNamespace ) {
1235                         $p .= $this->getNsText() . ':';
1236                 }
1237                 return $p . $name;
1238         }
1239
1240         /**
1241          * Get the prefixed database key form
1242          *
1243          * @return String the prefixed title, with underscores and
1244          *  any interwiki and namespace prefixes
1245          */
1246         public function getPrefixedDBkey() {
1247                 $s = $this->prefix( $this->mDbkeyform );
1248                 $s = str_replace( ' ', '_', $s );
1249                 return $s;
1250         }
1251
1252         /**
1253          * Get the prefixed title with spaces.
1254          * This is the form usually used for display
1255          *
1256          * @return String the prefixed title, with spaces
1257          */
1258         public function getPrefixedText() {
1259                 // @todo FIXME: Bad usage of empty() ?
1260                 if ( empty( $this->mPrefixedText ) ) {
1261                         $s = $this->prefix( $this->mTextform );
1262                         $s = str_replace( '_', ' ', $s );
1263                         $this->mPrefixedText = $s;
1264                 }
1265                 return $this->mPrefixedText;
1266         }
1267
1268         /**
1269          * Return a string representation of this title
1270          *
1271          * @return String representation of this title
1272          */
1273         public function __toString() {
1274                 return $this->getPrefixedText();
1275         }
1276
1277         /**
1278          * Get the prefixed title with spaces, plus any fragment
1279          * (part beginning with '#')
1280          *
1281          * @return String the prefixed title, with spaces and the fragment, including '#'
1282          */
1283         public function getFullText() {
1284                 $text = $this->getPrefixedText();
1285                 if ( $this->mFragment != '' ) {
1286                         $text .= '#' . $this->mFragment;
1287                 }
1288                 return $text;
1289         }
1290
1291         /**
1292          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1293          *
1294          * @par Example:
1295          * @code
1296          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1297          * # returns: 'Foo'
1298          * @endcode
1299          *
1300          * @return String Root name
1301          * @since 1.20
1302          */
1303         public function getRootText() {
1304                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1305                         return $this->getText();
1306                 }
1307
1308                 return strtok( $this->getText(), '/' );
1309         }
1310
1311         /**
1312          * Get the root page name title, i.e. the leftmost part before any slashes
1313          *
1314          * @par Example:
1315          * @code
1316          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1317          * # returns: Title{User:Foo}
1318          * @endcode
1319          *
1320          * @return Title Root title
1321          * @since 1.20
1322          */
1323         public function getRootTitle() {
1324                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1325         }
1326
1327         /**
1328          * Get the base page name without a namespace, i.e. the part before the subpage name
1329          *
1330          * @par Example:
1331          * @code
1332          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1333          * # returns: 'Foo/Bar'
1334          * @endcode
1335          *
1336          * @return String Base name
1337          */
1338         public function getBaseText() {
1339                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1340                         return $this->getText();
1341                 }
1342
1343                 $parts = explode( '/', $this->getText() );
1344                 # Don't discard the real title if there's no subpage involved
1345                 if ( count( $parts ) > 1 ) {
1346                         unset( $parts[count( $parts ) - 1] );
1347                 }
1348                 return implode( '/', $parts );
1349         }
1350
1351         /**
1352          * Get the base page name title, i.e. the part before the subpage name
1353          *
1354          * @par Example:
1355          * @code
1356          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1357          * # returns: Title{User:Foo/Bar}
1358          * @endcode
1359          *
1360          * @return Title Base title
1361          * @since 1.20
1362          */
1363         public function getBaseTitle() {
1364                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1365         }
1366
1367         /**
1368          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1369          *
1370          * @par Example:
1371          * @code
1372          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1373          * # returns: "Baz"
1374          * @endcode
1375          *
1376          * @return String Subpage name
1377          */
1378         public function getSubpageText() {
1379                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1380                         return $this->mTextform;
1381                 }
1382                 $parts = explode( '/', $this->mTextform );
1383                 return $parts[count( $parts ) - 1];
1384         }
1385
1386         /**
1387          * Get the title for a subpage of the current page
1388          *
1389          * @par Example:
1390          * @code
1391          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1392          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1393          * @endcode
1394          *
1395          * @param string $text The subpage name to add to the title
1396          * @return Title Subpage title
1397          * @since 1.20
1398          */
1399         public function getSubpage( $text ) {
1400                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1401         }
1402
1403         /**
1404          * Get the HTML-escaped displayable text form.
1405          * Used for the title field in <a> tags.
1406          *
1407          * @return String the text, including any prefixes
1408          * @deprecated since 1.19
1409          */
1410         public function getEscapedText() {
1411                 wfDeprecated( __METHOD__, '1.19' );
1412                 return htmlspecialchars( $this->getPrefixedText() );
1413         }
1414
1415         /**
1416          * Get a URL-encoded form of the subpage text
1417          *
1418          * @return String URL-encoded subpage name
1419          */
1420         public function getSubpageUrlForm() {
1421                 $text = $this->getSubpageText();
1422                 $text = wfUrlencode( str_replace( ' ', '_', $text ) );
1423                 return $text;
1424         }
1425
1426         /**
1427          * Get a URL-encoded title (not an actual URL) including interwiki
1428          *
1429          * @return String the URL-encoded form
1430          */
1431         public function getPrefixedURL() {
1432                 $s = $this->prefix( $this->mDbkeyform );
1433                 $s = wfUrlencode( str_replace( ' ', '_', $s ) );
1434                 return $s;
1435         }
1436
1437         /**
1438          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1439          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1440          * second argument named variant. This was deprecated in favor
1441          * of passing an array of option with a "variant" key
1442          * Once $query2 is removed for good, this helper can be dropped
1443          * and the wfArrayToCgi moved to getLocalURL();
1444          *
1445          * @since 1.19 (r105919)
1446          * @param $query
1447          * @param $query2 bool
1448          * @return String
1449          */
1450         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1451                 if ( $query2 !== false ) {
1452                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1453                                 "method called with a second parameter is deprecated. Add your " .
1454                                 "parameter to an array passed as the first parameter.", "1.19" );
1455                 }
1456                 if ( is_array( $query ) ) {
1457                         $query = wfArrayToCgi( $query );
1458                 }
1459                 if ( $query2 ) {
1460                         if ( is_string( $query2 ) ) {
1461                                 // $query2 is a string, we will consider this to be
1462                                 // a deprecated $variant argument and add it to the query
1463                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1464                         } else {
1465                                 $query2 = wfArrayToCgi( $query2 );
1466                         }
1467                         // If we have $query content add a & to it first
1468                         if ( $query ) {
1469                                 $query .= '&';
1470                         }
1471                         // Now append the queries together
1472                         $query .= $query2;
1473                 }
1474                 return $query;
1475         }
1476
1477         /**
1478          * Get a real URL referring to this title, with interwiki link and
1479          * fragment
1480          *
1481          * See getLocalURL for the arguments.
1482          *
1483          * @see self::getLocalURL
1484          * @see wfExpandUrl
1485          * @param $query
1486          * @param $query2 bool
1487          * @param $proto Protocol type to use in URL
1488          * @return String the URL
1489          */
1490         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1491                 $query = self::fixUrlQueryArgs( $query, $query2 );
1492
1493                 # Hand off all the decisions on urls to getLocalURL
1494                 $url = $this->getLocalURL( $query );
1495
1496                 # Expand the url to make it a full url. Note that getLocalURL has the
1497                 # potential to output full urls for a variety of reasons, so we use
1498                 # wfExpandUrl instead of simply prepending $wgServer
1499                 $url = wfExpandUrl( $url, $proto );
1500
1501                 # Finally, add the fragment.
1502                 $url .= $this->getFragmentForURL();
1503
1504                 wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
1505                 return $url;
1506         }
1507
1508         /**
1509          * Get a URL with no fragment or server name.  If this page is generated
1510          * with action=render, $wgServer is prepended.
1511          *
1512          * @param string|array $query an optional query string,
1513          *   not used for interwiki links. Can be specified as an associative array as well,
1514          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1515          *   Some query patterns will trigger various shorturl path replacements.
1516          * @param $query2 Mixed: An optional secondary query array. This one MUST
1517          *   be an array. If a string is passed it will be interpreted as a deprecated
1518          *   variant argument and urlencoded into a variant= argument.
1519          *   This second query argument will be added to the $query
1520          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1521          *   pair in the first parameter array instead.
1522          *
1523          * @return String the URL
1524          */
1525         public function getLocalURL( $query = '', $query2 = false ) {
1526                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1527
1528                 $query = self::fixUrlQueryArgs( $query, $query2 );
1529
1530                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1531                 if ( $interwiki ) {
1532                         $namespace = $this->getNsText();
1533                         if ( $namespace != '' ) {
1534                                 # Can this actually happen? Interwikis shouldn't be parsed.
1535                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1536                                 $namespace .= ':';
1537                         }
1538                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1539                         $url = wfAppendQuery( $url, $query );
1540                 } else {
1541                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1542                         if ( $query == '' ) {
1543                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1544                                 wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
1545                         } else {
1546                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1547                                 $url = false;
1548                                 $matches = array();
1549
1550                                 if ( !empty( $wgActionPaths ) &&
1551                                         preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches ) )
1552                                 {
1553                                         $action = urldecode( $matches[2] );
1554                                         if ( isset( $wgActionPaths[$action] ) ) {
1555                                                 $query = $matches[1];
1556                                                 if ( isset( $matches[4] ) ) {
1557                                                         $query .= $matches[4];
1558                                                 }
1559                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1560                                                 if ( $query != '' ) {
1561                                                         $url = wfAppendQuery( $url, $query );
1562                                                 }
1563                                         }
1564                                 }
1565
1566                                 if ( $url === false &&
1567                                         $wgVariantArticlePath &&
1568                                         $wgContLang->getCode() === $this->getPageLanguage()->getCode() &&
1569                                         $this->getPageLanguage()->hasVariants() &&
1570                                         preg_match( '/^variant=([^&]*)$/', $query, $matches ) )
1571                                 {
1572                                         $variant = urldecode( $matches[1] );
1573                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1574                                                 // Only do the variant replacement if the given variant is a valid
1575                                                 // variant for the page's language.
1576                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1577                                                 $url = str_replace( '$1', $dbkey, $url );
1578                                         }
1579                                 }
1580
1581                                 if ( $url === false ) {
1582                                         if ( $query == '-' ) {
1583                                                 $query = '';
1584                                         }
1585                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1586                                 }
1587                         }
1588
1589                         wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1590
1591                         // @todo FIXME: This causes breakage in various places when we
1592                         // actually expected a local URL and end up with dupe prefixes.
1593                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1594                                 $url = $wgServer . $url;
1595                         }
1596                 }
1597                 wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
1598                 return $url;
1599         }
1600
1601         /**
1602          * Get a URL that's the simplest URL that will be valid to link, locally,
1603          * to the current Title.  It includes the fragment, but does not include
1604          * the server unless action=render is used (or the link is external).  If
1605          * there's a fragment but the prefixed text is empty, we just return a link
1606          * to the fragment.
1607          *
1608          * The result obviously should not be URL-escaped, but does need to be
1609          * HTML-escaped if it's being output in HTML.
1610          *
1611          * See getLocalURL for the arguments.
1612          *
1613          * @param $query
1614          * @param $query2 bool
1615          * @param $proto Protocol to use; setting this will cause a full URL to be used
1616          * @see self::getLocalURL
1617          * @return String the URL
1618          */
1619         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1620                 wfProfileIn( __METHOD__ );
1621                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1622                         $ret = $this->getFullURL( $query, $query2, $proto );
1623                 } elseif ( $this->getPrefixedText() === '' && $this->getFragment() !== '' ) {
1624                         $ret = $this->getFragmentForURL();
1625                 } else {
1626                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1627                 }
1628                 wfProfileOut( __METHOD__ );
1629                 return $ret;
1630         }
1631
1632         /**
1633          * Get an HTML-escaped version of the URL form, suitable for
1634          * using in a link, without a server name or fragment
1635          *
1636          * See getLocalURL for the arguments.
1637          *
1638          * @see self::getLocalURL
1639          * @param $query string
1640          * @param $query2 bool|string
1641          * @return String the URL
1642          * @deprecated since 1.19
1643          */
1644         public function escapeLocalURL( $query = '', $query2 = false ) {
1645                 wfDeprecated( __METHOD__, '1.19' );
1646                 return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
1647         }
1648
1649         /**
1650          * Get an HTML-escaped version of the URL form, suitable for
1651          * using in a link, including the server name and fragment
1652          *
1653          * See getLocalURL for the arguments.
1654          *
1655          * @see self::getLocalURL
1656          * @return String the URL
1657          * @deprecated since 1.19
1658          */
1659         public function escapeFullURL( $query = '', $query2 = false ) {
1660                 wfDeprecated( __METHOD__, '1.19' );
1661                 return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
1662         }
1663
1664         /**
1665          * Get the URL form for an internal link.
1666          * - Used in various Squid-related code, in case we have a different
1667          * internal hostname for the server from the exposed one.
1668          *
1669          * This uses $wgInternalServer to qualify the path, or $wgServer
1670          * if $wgInternalServer is not set. If the server variable used is
1671          * protocol-relative, the URL will be expanded to http://
1672          *
1673          * See getLocalURL for the arguments.
1674          *
1675          * @see self::getLocalURL
1676          * @return String the URL
1677          */
1678         public function getInternalURL( $query = '', $query2 = false ) {
1679                 global $wgInternalServer, $wgServer;
1680                 $query = self::fixUrlQueryArgs( $query, $query2 );
1681                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1682                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1683                 wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
1684                 return $url;
1685         }
1686
1687         /**
1688          * Get the URL for a canonical link, for use in things like IRC and
1689          * e-mail notifications. Uses $wgCanonicalServer and the
1690          * GetCanonicalURL hook.
1691          *
1692          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1693          *
1694          * See getLocalURL for the arguments.
1695          *
1696          * @see self::getLocalURL
1697          * @return string The URL
1698          * @since 1.18
1699          */
1700         public function getCanonicalURL( $query = '', $query2 = false ) {
1701                 $query = self::fixUrlQueryArgs( $query, $query2 );
1702                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1703                 wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1704                 return $url;
1705         }
1706
1707         /**
1708          * HTML-escaped version of getCanonicalURL()
1709          *
1710          * See getLocalURL for the arguments.
1711          *
1712          * @see self::getLocalURL
1713          * @since 1.18
1714          * @return string
1715          * @deprecated since 1.19
1716          */
1717         public function escapeCanonicalURL( $query = '', $query2 = false ) {
1718                 wfDeprecated( __METHOD__, '1.19' );
1719                 return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
1720         }
1721
1722         /**
1723          * Get the edit URL for this Title
1724          *
1725          * @return String the URL, or a null string if this is an
1726          *  interwiki link
1727          */
1728         public function getEditURL() {
1729                 if ( $this->mInterwiki != '' ) {
1730                         return '';
1731                 }
1732                 $s = $this->getLocalURL( 'action=edit' );
1733
1734                 return $s;
1735         }
1736
1737         /**
1738          * Is $wgUser watching this page?
1739          *
1740          * @deprecated in 1.20; use User::isWatched() instead.
1741          * @return Bool
1742          */
1743         public function userIsWatching() {
1744                 global $wgUser;
1745
1746                 if ( is_null( $this->mWatched ) ) {
1747                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1748                                 $this->mWatched = false;
1749                         } else {
1750                                 $this->mWatched = $wgUser->isWatched( $this );
1751                         }
1752                 }
1753                 return $this->mWatched;
1754         }
1755
1756         /**
1757          * Can $wgUser read this page?
1758          *
1759          * @deprecated in 1.19; use userCan(), quickUserCan() or getUserPermissionsErrors() instead
1760          * @return Bool
1761          * @todo fold these checks into userCan()
1762          */
1763         public function userCanRead() {
1764                 wfDeprecated( __METHOD__, '1.19' );
1765                 return $this->userCan( 'read' );
1766         }
1767
1768         /**
1769          * Can $user perform $action on this page?
1770          * This skips potentially expensive cascading permission checks
1771          * as well as avoids expensive error formatting
1772          *
1773          * Suitable for use for nonessential UI controls in common cases, but
1774          * _not_ for functional access control.
1775          *
1776          * May provide false positives, but should never provide a false negative.
1777          *
1778          * @param string $action action that permission needs to be checked for
1779          * @param $user User to check (since 1.19); $wgUser will be used if not
1780          *              provided.
1781          * @return Bool
1782          */
1783         public function quickUserCan( $action, $user = null ) {
1784                 return $this->userCan( $action, $user, false );
1785         }
1786
1787         /**
1788          * Can $user perform $action on this page?
1789          *
1790          * @param string $action action that permission needs to be checked for
1791          * @param $user User to check (since 1.19); $wgUser will be used if not
1792          *   provided.
1793          * @param bool $doExpensiveQueries Set this to false to avoid doing
1794          *   unnecessary queries.
1795          * @return Bool
1796          */
1797         public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
1798                 if ( !$user instanceof User ) {
1799                         global $wgUser;
1800                         $user = $wgUser;
1801                 }
1802                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries, true ) );
1803         }
1804
1805         /**
1806          * Can $user perform $action on this page?
1807          *
1808          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1809          *
1810          * @param string $action action that permission needs to be checked for
1811          * @param $user User to check
1812          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary
1813          *   queries by skipping checks for cascading protections and user blocks.
1814          * @param array $ignoreErrors of Strings Set this to a list of message keys
1815          *   whose corresponding errors may be ignored.
1816          * @return Array of arguments to wfMessage to explain permissions problems.
1817          */
1818         public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
1819                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );
1820
1821                 // Remove the errors being ignored.
1822                 foreach ( $errors as $index => $error ) {
1823                         $error_key = is_array( $error ) ? $error[0] : $error;
1824
1825                         if ( in_array( $error_key, $ignoreErrors ) ) {
1826                                 unset( $errors[$index] );
1827                         }
1828                 }
1829
1830                 return $errors;
1831         }
1832
1833         /**
1834          * Permissions checks that fail most often, and which are easiest to test.
1835          *
1836          * @param string $action the action to check
1837          * @param $user User user to check
1838          * @param array $errors list of current errors
1839          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1840          * @param $short Boolean short circuit on first error
1841          *
1842          * @return Array list of errors
1843          */
1844         private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1845                 if ( !wfRunHooks( 'TitleQuickPermissions', array( $this, $user, $action, &$errors, $doExpensiveQueries, $short ) ) ) {
1846                         return $errors;
1847                 }
1848
1849                 if ( $action == 'create' ) {
1850                         if (
1851                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1852                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1853                         ) {
1854                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1855                         }
1856                 } elseif ( $action == 'move' ) {
1857                         if ( !$user->isAllowed( 'move-rootuserpages' )
1858                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1859                                 // Show user page-specific message only if the user can move other pages
1860                                 $errors[] = array( 'cant-move-user-page' );
1861                         }
1862
1863                         // Check if user is allowed to move files if it's a file
1864                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
1865                                 $errors[] = array( 'movenotallowedfile' );
1866                         }
1867
1868                         if ( !$user->isAllowed( 'move' ) ) {
1869                                 // User can't move anything
1870                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
1871                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
1872                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
1873                                         // custom message if logged-in users without any special rights can move
1874                                         $errors[] = array( 'movenologintext' );
1875                                 } else {
1876                                         $errors[] = array( 'movenotallowed' );
1877                                 }
1878                         }
1879                 } elseif ( $action == 'move-target' ) {
1880                         if ( !$user->isAllowed( 'move' ) ) {
1881                                 // User can't move anything
1882                                 $errors[] = array( 'movenotallowed' );
1883                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
1884                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1885                                 // Show user page-specific message only if the user can move other pages
1886                                 $errors[] = array( 'cant-move-to-user-page' );
1887                         }
1888                 } elseif ( !$user->isAllowed( $action ) ) {
1889                         $errors[] = $this->missingPermissionError( $action, $short );
1890                 }
1891
1892                 return $errors;
1893         }
1894
1895         /**
1896          * Add the resulting error code to the errors array
1897          *
1898          * @param array $errors list of current errors
1899          * @param $result Mixed result of errors
1900          *
1901          * @return Array list of errors
1902          */
1903         private function resultToError( $errors, $result ) {
1904                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
1905                         // A single array representing an error
1906                         $errors[] = $result;
1907                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
1908                         // A nested array representing multiple errors
1909                         $errors = array_merge( $errors, $result );
1910                 } elseif ( $result !== '' && is_string( $result ) ) {
1911                         // A string representing a message-id
1912                         $errors[] = array( $result );
1913                 } elseif ( $result === false ) {
1914                         // a generic "We don't want them to do that"
1915                         $errors[] = array( 'badaccess-group0' );
1916                 }
1917                 return $errors;
1918         }
1919
1920         /**
1921          * Check various permission hooks
1922          *
1923          * @param string $action the action to check
1924          * @param $user User user to check
1925          * @param array $errors list of current errors
1926          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1927          * @param $short Boolean short circuit on first error
1928          *
1929          * @return Array list of errors
1930          */
1931         private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
1932                 // Use getUserPermissionsErrors instead
1933                 $result = '';
1934                 if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
1935                         return $result ? array() : array( array( 'badaccess-group0' ) );
1936                 }
1937                 // Check getUserPermissionsErrors hook
1938                 if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
1939                         $errors = $this->resultToError( $errors, $result );
1940                 }
1941                 // Check getUserPermissionsErrorsExpensive hook
1942                 if (
1943                         $doExpensiveQueries
1944                         && !( $short && count( $errors ) > 0 )
1945                         && !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
1946                 ) {
1947                         $errors = $this->resultToError( $errors, $result );
1948                 }
1949
1950                 return $errors;
1951         }
1952
1953         /**
1954          * Check permissions on special pages & namespaces
1955          *
1956          * @param string $action the action to check
1957          * @param $user User user to check
1958          * @param array $errors list of current errors
1959          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1960          * @param $short Boolean short circuit on first error
1961          *
1962          * @return Array list of errors
1963          */
1964         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1965                 # Only 'createaccount' can be performed on special pages,
1966                 # which don't actually exist in the DB.
1967                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
1968                         $errors[] = array( 'ns-specialprotected' );
1969                 }
1970
1971                 # Check $wgNamespaceProtection for restricted namespaces
1972                 if ( $this->isNamespaceProtected( $user ) ) {
1973                         $ns = $this->mNamespace == NS_MAIN ?
1974                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
1975                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
1976                                 array( 'protectedinterface' ) : array( 'namespaceprotected', $ns );
1977                 }
1978
1979                 return $errors;
1980         }
1981
1982         /**
1983          * Check CSS/JS sub-page permissions
1984          *
1985          * @param string $action the action to check
1986          * @param $user User user to check
1987          * @param array $errors list of current errors
1988          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
1989          * @param $short Boolean short circuit on first error
1990          *
1991          * @return Array list of errors
1992          */
1993         private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
1994                 # Protect css/js subpages of user pages
1995                 # XXX: this might be better using restrictions
1996                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
1997                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
1998                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
1999                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2000                                         $errors[] = array( 'mycustomcssprotected' );
2001                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2002                                         $errors[] = array( 'mycustomjsprotected' );
2003                                 }
2004                         } else {
2005                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2006                                         $errors[] = array( 'customcssprotected' );
2007                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2008                                         $errors[] = array( 'customjsprotected' );
2009                                 }
2010                         }
2011                 }
2012
2013                 return $errors;
2014         }
2015
2016         /**
2017          * Check against page_restrictions table requirements on this
2018          * page. The user must possess all required rights for this
2019          * action.
2020          *
2021          * @param string $action the action to check
2022          * @param $user User user to check
2023          * @param array $errors list of current errors
2024          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2025          * @param $short Boolean short circuit on first error
2026          *
2027          * @return Array list of errors
2028          */
2029         private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2030                 foreach ( $this->getRestrictions( $action ) as $right ) {
2031                         // Backwards compatibility, rewrite sysop -> editprotected
2032                         if ( $right == 'sysop' ) {
2033                                 $right = 'editprotected';
2034                         }
2035                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2036                         if ( $right == 'autoconfirmed' ) {
2037                                 $right = 'editsemiprotected';
2038                         }
2039                         if ( $right == '' ) {
2040                                 continue;
2041                         }
2042                         if ( !$user->isAllowed( $right ) ) {
2043                                 $errors[] = array( 'protectedpagetext', $right );
2044                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2045                                 $errors[] = array( 'protectedpagetext', 'protect' );
2046                         }
2047                 }
2048
2049                 return $errors;
2050         }
2051
2052         /**
2053          * Check restrictions on cascading pages.
2054          *
2055          * @param string $action the action to check
2056          * @param $user User to check
2057          * @param array $errors list of current errors
2058          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2059          * @param $short Boolean short circuit on first error
2060          *
2061          * @return Array list of errors
2062          */
2063         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2064                 if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
2065                         # We /could/ use the protection level on the source page, but it's
2066                         # fairly ugly as we have to establish a precedence hierarchy for pages
2067                         # included by multiple cascade-protected pages. So just restrict
2068                         # it to people with 'protect' permission, as they could remove the
2069                         # protection anyway.
2070                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2071                         # Cascading protection depends on more than this page...
2072                         # Several cascading protected pages may include this page...
2073                         # Check each cascading level
2074                         # This is only for protection restrictions, not for all actions
2075                         if ( isset( $restrictions[$action] ) ) {
2076                                 foreach ( $restrictions[$action] as $right ) {
2077                                         // Backwards compatibility, rewrite sysop -> editprotected
2078                                         if ( $right == 'sysop' ) {
2079                                                 $right = 'editprotected';
2080                                         }
2081                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2082                                         if ( $right == 'autoconfirmed' ) {
2083                                                 $right = 'editsemiprotected';
2084                                         }
2085                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2086                                                 $pages = '';
2087                                                 foreach ( $cascadingSources as $page ) {
2088                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2089                                                 }
2090                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
2091                                         }
2092                                 }
2093                         }
2094                 }
2095
2096                 return $errors;
2097         }
2098
2099         /**
2100          * Check action permissions not already checked in checkQuickPermissions
2101          *
2102          * @param string $action the action to check
2103          * @param $user User to check
2104          * @param array $errors list of current errors
2105          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2106          * @param $short Boolean short circuit on first error
2107          *
2108          * @return Array list of errors
2109          */
2110         private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2111                 global $wgDeleteRevisionsLimit, $wgLang;
2112
2113                 if ( $action == 'protect' ) {
2114                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $doExpensiveQueries, true ) ) ) {
2115                                 // If they can't edit, they shouldn't protect.
2116                                 $errors[] = array( 'protect-cantedit' );
2117                         }
2118                 } elseif ( $action == 'create' ) {
2119                         $title_protection = $this->getTitleProtection();
2120                         if ( $title_protection ) {
2121                                 if ( $title_protection['pt_create_perm'] == 'sysop' ) {
2122                                         $title_protection['pt_create_perm'] = 'editprotected'; // B/C
2123                                 }
2124                                 if ( $title_protection['pt_create_perm'] == 'autoconfirmed' ) {
2125                                         $title_protection['pt_create_perm'] = 'editsemiprotected'; // B/C
2126                                 }
2127                                 if ( $title_protection['pt_create_perm'] == '' ||
2128                                         !$user->isAllowed( $title_protection['pt_create_perm'] ) )
2129                                 {
2130                                         $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
2131                                 }
2132                         }
2133                 } elseif ( $action == 'move' ) {
2134                         // Check for immobile pages
2135                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2136                                 // Specific message for this case
2137                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2138                         } elseif ( !$this->isMovable() ) {
2139                                 // Less specific message for rarer cases
2140                                 $errors[] = array( 'immobile-source-page' );
2141                         }
2142                 } elseif ( $action == 'move-target' ) {
2143                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2144                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2145                         } elseif ( !$this->isMovable() ) {
2146                                 $errors[] = array( 'immobile-target-page' );
2147                         }
2148                 } elseif ( $action == 'delete' ) {
2149                         if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
2150                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion() )
2151                         {
2152                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2153                         }
2154                 }
2155                 return $errors;
2156         }
2157
2158         /**
2159          * Check that the user isn't blocked from editing.
2160          *
2161          * @param string $action the action to check
2162          * @param $user User to check
2163          * @param array $errors list of current errors
2164          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2165          * @param $short Boolean short circuit on first error
2166          *
2167          * @return Array list of errors
2168          */
2169         private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
2170                 // Account creation blocks handled at userlogin.
2171                 // Unblocking handled in SpecialUnblock
2172                 if ( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2173                         return $errors;
2174                 }
2175
2176                 global $wgEmailConfirmToEdit;
2177
2178                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2179                         $errors[] = array( 'confirmedittext' );
2180                 }
2181
2182                 if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
2183                         // Don't block the user from editing their own talk page unless they've been
2184                         // explicitly blocked from that too.
2185                 } elseif ( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
2186                         // @todo FIXME: Pass the relevant context into this function.
2187                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2188                 }
2189
2190                 return $errors;
2191         }
2192
2193         /**
2194          * Check that the user is allowed to read this page.
2195          *
2196          * @param string $action the action to check
2197          * @param $user User to check
2198          * @param array $errors list of current errors
2199          * @param $doExpensiveQueries Boolean whether or not to perform expensive queries
2200          * @param $short Boolean short circuit on first error
2201          *
2202          * @return Array list of errors
2203          */
2204         private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
2205                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2206
2207                 $whitelisted = false;
2208                 if ( User::isEveryoneAllowed( 'read' ) ) {
2209                         # Shortcut for public wikis, allows skipping quite a bit of code
2210                         $whitelisted = true;
2211                 } elseif ( $user->isAllowed( 'read' ) ) {
2212                         # If the user is allowed to read pages, he is allowed to read all pages
2213                         $whitelisted = true;
2214                 } elseif ( $this->isSpecial( 'Userlogin' )
2215                         || $this->isSpecial( 'ChangePassword' )
2216                         || $this->isSpecial( 'PasswordReset' )
2217                 ) {
2218                         # Always grant access to the login page.
2219                         # Even anons need to be able to log in.
2220                         $whitelisted = true;
2221                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2222                         # Time to check the whitelist
2223                         # Only do these checks is there's something to check against
2224                         $name = $this->getPrefixedText();
2225                         $dbName = $this->getPrefixedDBkey();
2226
2227                         // Check for explicit whitelisting with and without underscores
2228                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2229                                 $whitelisted = true;
2230                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2231                                 # Old settings might have the title prefixed with
2232                                 # a colon for main-namespace pages
2233                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2234                                         $whitelisted = true;
2235                                 }
2236                         } elseif ( $this->isSpecialPage() ) {
2237                                 # If it's a special page, ditch the subpage bit and check again
2238                                 $name = $this->getDBkey();
2239                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2240                                 if ( $name ) {
2241                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2242                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2243                                                 $whitelisted = true;
2244                                         }
2245                                 }
2246                         }
2247                 }
2248
2249                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2250                         $name = $this->getPrefixedText();
2251                         // Check for regex whitelisting
2252                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2253                                 if ( preg_match( $listItem, $name ) ) {
2254                                         $whitelisted = true;
2255                                         break;
2256                                 }
2257                         }
2258                 }
2259
2260                 if ( !$whitelisted ) {
2261                         # If the title is not whitelisted, give extensions a chance to do so...
2262                         wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2263                         if ( !$whitelisted ) {
2264                                 $errors[] = $this->missingPermissionError( $action, $short );
2265                         }
2266                 }
2267
2268                 return $errors;
2269         }
2270
2271         /**
2272          * Get a description array when the user doesn't have the right to perform
2273          * $action (i.e. when User::isAllowed() returns false)
2274          *
2275          * @param string $action the action to check
2276          * @param $short Boolean short circuit on first error
2277          * @return Array list of errors
2278          */
2279         private function missingPermissionError( $action, $short ) {
2280                 // We avoid expensive display logic for quickUserCan's and such
2281                 if ( $short ) {
2282                         return array( 'badaccess-group0' );
2283                 }
2284
2285                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2286                         User::getGroupsWithPermission( $action ) );
2287
2288                 if ( count( $groups ) ) {
2289                         global $wgLang;
2290                         return array(
2291                                 'badaccess-groups',
2292                                 $wgLang->commaList( $groups ),
2293                                 count( $groups )
2294                         );
2295                 } else {
2296                         return array( 'badaccess-group0' );
2297                 }
2298         }
2299
2300         /**
2301          * Can $user perform $action on this page? This is an internal function,
2302          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2303          * checks on wfReadOnly() and blocks)
2304          *
2305          * @param string $action action that permission needs to be checked for
2306          * @param $user User to check
2307          * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
2308          * @param bool $short Set this to true to stop after the first permission error.
2309          * @return Array of arrays of the arguments to wfMessage to explain permissions problems.
2310          */
2311         protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
2312                 wfProfileIn( __METHOD__ );
2313
2314                 # Read has special handling
2315                 if ( $action == 'read' ) {
2316                         $checks = array(
2317                                 'checkPermissionHooks',
2318                                 'checkReadPermissions',
2319                         );
2320                 } else {
2321                         $checks = array(
2322                                 'checkQuickPermissions',
2323                                 'checkPermissionHooks',
2324                                 'checkSpecialsAndNSPermissions',
2325                                 'checkCSSandJSPermissions',
2326                                 'checkPageRestrictions',
2327                                 'checkCascadingSourcesRestrictions',
2328                                 'checkActionPermissions',
2329                                 'checkUserBlock'
2330                         );
2331                 }
2332
2333                 $errors = array();
2334                 while ( count( $checks ) > 0 &&
2335                                 !( $short && count( $errors ) > 0 ) ) {
2336                         $method = array_shift( $checks );
2337                         $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
2338                 }
2339
2340                 wfProfileOut( __METHOD__ );
2341                 return $errors;
2342         }
2343
2344         /**
2345          * Get a filtered list of all restriction types supported by this wiki.
2346          * @param bool $exists True to get all restriction types that apply to
2347          * titles that do exist, False for all restriction types that apply to
2348          * titles that do not exist
2349          * @return array
2350          */
2351         public static function getFilteredRestrictionTypes( $exists = true ) {
2352                 global $wgRestrictionTypes;
2353                 $types = $wgRestrictionTypes;
2354                 if ( $exists ) {
2355                         # Remove the create restriction for existing titles
2356                         $types = array_diff( $types, array( 'create' ) );
2357                 } else {
2358                         # Only the create and upload restrictions apply to non-existing titles
2359                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2360                 }
2361                 return $types;
2362         }
2363
2364         /**
2365          * Returns restriction types for the current Title
2366          *
2367          * @return array applicable restriction types
2368          */
2369         public function getRestrictionTypes() {
2370                 if ( $this->isSpecialPage() ) {
2371                         return array();
2372                 }
2373
2374                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2375
2376                 if ( $this->getNamespace() != NS_FILE ) {
2377                         # Remove the upload restriction for non-file titles
2378                         $types = array_diff( $types, array( 'upload' ) );
2379                 }
2380
2381                 wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2382
2383                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2384                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2385
2386                 return $types;
2387         }
2388
2389         /**
2390          * Is this title subject to title protection?
2391          * Title protection is the one applied against creation of such title.
2392          *
2393          * @return Mixed An associative array representing any existent title
2394          *   protection, or false if there's none.
2395          */
2396         private function getTitleProtection() {
2397                 // Can't protect pages in special namespaces
2398                 if ( $this->getNamespace() < 0 ) {
2399                         return false;
2400                 }
2401
2402                 // Can't protect pages that exist.
2403                 if ( $this->exists() ) {
2404                         return false;
2405                 }
2406
2407                 if ( !isset( $this->mTitleProtection ) ) {
2408                         $dbr = wfGetDB( DB_SLAVE );
2409                         $res = $dbr->select(
2410                                 'protected_titles',
2411                                 array( 'pt_user', 'pt_reason', 'pt_expiry', 'pt_create_perm' ),
2412                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2413                                 __METHOD__
2414                         );
2415
2416                         // fetchRow returns false if there are no rows.
2417                         $this->mTitleProtection = $dbr->fetchRow( $res );
2418                 }
2419                 return $this->mTitleProtection;
2420         }
2421
2422         /**
2423          * Update the title protection status
2424          *
2425          * @deprecated in 1.19; use WikiPage::doUpdateRestrictions() instead.
2426          * @param $create_perm String Permission required for creation
2427          * @param string $reason Reason for protection
2428          * @param string $expiry Expiry timestamp
2429          * @return boolean true
2430          */
2431         public function updateTitleProtection( $create_perm, $reason, $expiry ) {
2432                 wfDeprecated( __METHOD__, '1.19' );
2433
2434                 global $wgUser;
2435
2436                 $limit = array( 'create' => $create_perm );
2437                 $expiry = array( 'create' => $expiry );
2438
2439                 $page = WikiPage::factory( $this );
2440                 $cascade = false;
2441                 $status = $page->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $wgUser );
2442
2443                 return $status->isOK();
2444         }
2445
2446         /**
2447          * Remove any title protection due to page existing
2448          */
2449         public function deleteTitleProtection() {
2450                 $dbw = wfGetDB( DB_MASTER );
2451
2452                 $dbw->delete(
2453                         'protected_titles',
2454                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2455                         __METHOD__
2456                 );
2457                 $this->mTitleProtection = false;
2458         }
2459
2460         /**
2461          * Is this page "semi-protected" - the *only* protection is autoconfirm?
2462          *
2463          * @param string $action Action to check (default: edit)
2464          * @return Bool
2465          */
2466         public function isSemiProtected( $action = 'edit' ) {
2467                 if ( $this->exists() ) {
2468                         $restrictions = $this->getRestrictions( $action );
2469                         if ( count( $restrictions ) > 0 ) {
2470                                 foreach ( $restrictions as $restriction ) {
2471                                         if ( strtolower( $restriction ) != 'editsemiprotected' &&
2472                                                 strtolower( $restriction ) != 'autoconfirmed' // BC
2473                                         ) {
2474                                                 return false;
2475                                         }
2476                                 }
2477                         } else {
2478                                 # Not protected
2479                                 return false;
2480                         }
2481                         return true;
2482                 } else {
2483                         # If it doesn't exist, it can't be protected
2484                         return false;
2485                 }
2486         }
2487
2488         /**
2489          * Does the title correspond to a protected article?
2490          *
2491          * @param string $action the action the page is protected from,
2492          * by default checks all actions.
2493          * @return Bool
2494          */
2495         public function isProtected( $action = '' ) {
2496                 global $wgRestrictionLevels;
2497
2498                 $restrictionTypes = $this->getRestrictionTypes();
2499
2500                 # Special pages have inherent protection
2501                 if ( $this->isSpecialPage() ) {
2502                         return true;
2503                 }
2504
2505                 # Check regular protection levels
2506                 foreach ( $restrictionTypes as $type ) {
2507                         if ( $action == $type || $action == '' ) {
2508                                 $r = $this->getRestrictions( $type );
2509                                 foreach ( $wgRestrictionLevels as $level ) {
2510                                         if ( in_array( $level, $r ) && $level != '' ) {
2511                                                 return true;
2512                                         }
2513                                 }
2514                         }
2515                 }
2516
2517                 return false;
2518         }
2519
2520         /**
2521          * Determines if $user is unable to edit this page because it has been protected
2522          * by $wgNamespaceProtection.
2523          *
2524          * @param $user User object to check permissions
2525          * @return Bool
2526          */
2527         public function isNamespaceProtected( User $user ) {
2528                 global $wgNamespaceProtection;
2529
2530                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2531                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2532                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2533                                         return true;
2534                                 }
2535                         }
2536                 }
2537                 return false;
2538         }
2539
2540         /**
2541          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2542          *
2543          * @return Bool If the page is subject to cascading restrictions.
2544          */
2545         public function isCascadeProtected() {
2546                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2547                 return ( $sources > 0 );
2548         }
2549
2550         /**
2551          * Cascading protection: Get the source of any cascading restrictions on this page.
2552          *
2553          * @param bool $getPages Whether or not to retrieve the actual pages
2554          *        that the restrictions have come from.
2555          * @return Mixed Array of Title objects of the pages from which cascading restrictions
2556          *     have come, false for none, or true if such restrictions exist, but $getPages
2557          *     was not set.  The restriction array is an array of each type, each of which
2558          *     contains a array of unique groups.
2559          */
2560         public function getCascadeProtectionSources( $getPages = true ) {
2561                 global $wgContLang;
2562                 $pagerestrictions = array();
2563
2564                 if ( isset( $this->mCascadeSources ) && $getPages ) {
2565                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2566                 } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
2567                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2568                 }
2569
2570                 wfProfileIn( __METHOD__ );
2571
2572                 $dbr = wfGetDB( DB_SLAVE );
2573
2574                 if ( $this->getNamespace() == NS_FILE ) {
2575                         $tables = array( 'imagelinks', 'page_restrictions' );
2576                         $where_clauses = array(
2577                                 'il_to' => $this->getDBkey(),
2578                                 'il_from=pr_page',
2579                                 'pr_cascade' => 1
2580                         );
2581                 } else {
2582                         $tables = array( 'templatelinks', 'page_restrictions' );
2583                         $where_clauses = array(
2584                                 'tl_namespace' => $this->getNamespace(),
2585                                 'tl_title' => $this->getDBkey(),
2586                                 'tl_from=pr_page',
2587                                 'pr_cascade' => 1
2588                         );
2589                 }
2590
2591                 if ( $getPages ) {
2592                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2593                                 'pr_expiry', 'pr_type', 'pr_level' );
2594                         $where_clauses[] = 'page_id=pr_page';
2595                         $tables[] = 'page';
2596                 } else {
2597                         $cols = array( 'pr_expiry' );
2598                 }
2599
2600                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2601
2602                 $sources = $getPages ? array() : false;
2603                 $now = wfTimestampNow();
2604                 $purgeExpired = false;
2605
2606                 foreach ( $res as $row ) {
2607                         $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2608                         if ( $expiry > $now ) {
2609                                 if ( $getPages ) {
2610                                         $page_id = $row->pr_page;
2611                                         $page_ns = $row->page_namespace;
2612                                         $page_title = $row->page_title;
2613                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2614                                         # Add groups needed for each restriction type if its not already there
2615                                         # Make sure this restriction type still exists
2616
2617                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2618                                                 $pagerestrictions[$row->pr_type] = array();
2619                                         }
2620
2621                                         if (
2622                                                 isset( $pagerestrictions[$row->pr_type] )
2623                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2624                                         ) {
2625                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2626                                         }
2627                                 } else {
2628                                         $sources = true;
2629                                 }
2630                         } else {
2631                                 // Trigger lazy purge of expired restrictions from the db
2632                                 $purgeExpired = true;
2633                         }
2634                 }
2635                 if ( $purgeExpired ) {
2636                         Title::purgeExpiredRestrictions();
2637                 }
2638
2639                 if ( $getPages ) {
2640                         $this->mCascadeSources = $sources;
2641                         $this->mCascadingRestrictions = $pagerestrictions;
2642                 } else {
2643                         $this->mHasCascadingRestrictions = $sources;
2644                 }
2645
2646                 wfProfileOut( __METHOD__ );
2647                 return array( $sources, $pagerestrictions );
2648         }
2649
2650         /**
2651          * Accessor/initialisation for mRestrictions
2652          *
2653          * @param string $action action that permission needs to be checked for
2654          * @return Array of Strings the array of groups allowed to edit this article
2655          */
2656         public function getRestrictions( $action ) {
2657                 if ( !$this->mRestrictionsLoaded ) {
2658                         $this->loadRestrictions();
2659                 }
2660                 return isset( $this->mRestrictions[$action] )
2661                                 ? $this->mRestrictions[$action]
2662                                 : array();
2663         }
2664
2665         /**
2666          * Get the expiry time for the restriction against a given action
2667          *
2668          * @param $action
2669          * @return String|Bool 14-char timestamp, or 'infinity' if the page is protected forever
2670          *     or not protected at all, or false if the action is not recognised.
2671          */
2672         public function getRestrictionExpiry( $action ) {
2673                 if ( !$this->mRestrictionsLoaded ) {
2674                         $this->loadRestrictions();
2675                 }
2676                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2677         }
2678
2679         /**
2680          * Returns cascading restrictions for the current article
2681          *
2682          * @return Boolean
2683          */
2684         function areRestrictionsCascading() {
2685                 if ( !$this->mRestrictionsLoaded ) {
2686                         $this->loadRestrictions();
2687                 }
2688
2689                 return $this->mCascadeRestriction;
2690         }
2691
2692         /**
2693          * Loads a string into mRestrictions array
2694          *
2695          * @param $res Resource restrictions as an SQL result.
2696          * @param string $oldFashionedRestrictions comma-separated list of page
2697          *        restrictions from page table (pre 1.10)
2698          */
2699         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2700                 $rows = array();
2701
2702                 foreach ( $res as $row ) {
2703                         $rows[] = $row;
2704                 }
2705
2706                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2707         }
2708
2709         /**
2710          * Compiles list of active page restrictions from both page table (pre 1.10)
2711          * and page_restrictions table for this existing page.
2712          * Public for usage by LiquidThreads.
2713          *
2714          * @param array $rows of db result objects
2715          * @param string $oldFashionedRestrictions comma-separated list of page
2716          *        restrictions from page table (pre 1.10)
2717          */
2718         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2719                 global $wgContLang;
2720                 $dbr = wfGetDB( DB_SLAVE );
2721
2722                 $restrictionTypes = $this->getRestrictionTypes();
2723
2724                 foreach ( $restrictionTypes as $type ) {
2725                         $this->mRestrictions[$type] = array();
2726                         $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
2727                 }
2728
2729                 $this->mCascadeRestriction = false;
2730
2731                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2732
2733                 if ( $oldFashionedRestrictions === null ) {
2734                         $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2735                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2736                 }
2737
2738                 if ( $oldFashionedRestrictions != '' ) {
2739
2740                         foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
2741                                 $temp = explode( '=', trim( $restrict ) );
2742                                 if ( count( $temp ) == 1 ) {
2743                                         // old old format should be treated as edit/move restriction
2744                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2745                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2746                                 } else {
2747                                         $restriction = trim( $temp[1] );
2748                                         if ( $restriction != '' ) { //some old entries are empty
2749                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2750                                         }
2751                                 }
2752                         }
2753
2754                         $this->mOldRestrictions = true;
2755
2756                 }
2757
2758                 if ( count( $rows ) ) {
2759                         # Current system - load second to make them override.
2760                         $now = wfTimestampNow();
2761                         $purgeExpired = false;
2762
2763                         # Cycle through all the restrictions.
2764                         foreach ( $rows as $row ) {
2765
2766                                 // Don't take care of restrictions types that aren't allowed
2767                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2768                                         continue;
2769                                 }
2770
2771                                 // This code should be refactored, now that it's being used more generally,
2772                                 // But I don't really see any harm in leaving it in Block for now -werdna
2773                                 $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
2774
2775                                 // Only apply the restrictions if they haven't expired!
2776                                 if ( !$expiry || $expiry > $now ) {
2777                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2778                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2779
2780                                         $this->mCascadeRestriction |= $row->pr_cascade;
2781                                 } else {
2782                                         // Trigger a lazy purge of expired restrictions
2783                                         $purgeExpired = true;
2784                                 }
2785                         }
2786
2787                         if ( $purgeExpired ) {
2788                                 Title::purgeExpiredRestrictions();
2789                         }
2790                 }
2791
2792                 $this->mRestrictionsLoaded = true;
2793         }
2794
2795         /**
2796          * Load restrictions from the page_restrictions table
2797          *
2798          * @param string $oldFashionedRestrictions comma-separated list of page
2799          *        restrictions from page table (pre 1.10)
2800          */
2801         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2802                 global $wgContLang;
2803                 if ( !$this->mRestrictionsLoaded ) {
2804                         if ( $this->exists() ) {
2805                                 $dbr = wfGetDB( DB_SLAVE );
2806
2807                                 $res = $dbr->select(
2808                                         'page_restrictions',
2809                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
2810                                         array( 'pr_page' => $this->getArticleID() ),
2811                                         __METHOD__
2812                                 );
2813
2814                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
2815                         } else {
2816                                 $title_protection = $this->getTitleProtection();
2817
2818                                 if ( $title_protection ) {
2819                                         $now = wfTimestampNow();
2820                                         $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );
2821
2822                                         if ( !$expiry || $expiry > $now ) {
2823                                                 // Apply the restrictions
2824                                                 $this->mRestrictionsExpiry['create'] = $expiry;
2825                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
2826                                         } else { // Get rid of the old restrictions
2827                                                 Title::purgeExpiredRestrictions();
2828                                                 $this->mTitleProtection = false;
2829                                         }
2830                                 } else {
2831                                         $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
2832                                 }
2833                                 $this->mRestrictionsLoaded = true;
2834                         }
2835                 }
2836         }
2837
2838         /**
2839          * Flush the protection cache in this object and force reload from the database.
2840          * This is used when updating protection from WikiPage::doUpdateRestrictions().
2841          */
2842         public function flushRestrictions() {
2843                 $this->mRestrictionsLoaded = false;
2844                 $this->mTitleProtection = null;
2845         }
2846
2847         /**
2848          * Purge expired restrictions from the page_restrictions table
2849          */
2850         static function purgeExpiredRestrictions() {
2851                 if ( wfReadOnly() ) {
2852                         return;
2853                 }
2854
2855                 $method = __METHOD__;
2856                 $dbw = wfGetDB( DB_MASTER );
2857                 $dbw->onTransactionIdle( function() use ( $dbw, $method ) {
2858                         $dbw->delete(
2859                                 'page_restrictions',
2860                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2861                                 $method
2862                         );
2863                         $dbw->delete(
2864                                 'protected_titles',
2865                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
2866                                 $method
2867                         );
2868                 } );
2869         }
2870
2871         /**
2872          * Does this have subpages?  (Warning, usually requires an extra DB query.)
2873          *
2874          * @return Bool
2875          */
2876         public function hasSubpages() {
2877                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
2878                         # Duh
2879                         return false;
2880                 }
2881
2882                 # We dynamically add a member variable for the purpose of this method
2883                 # alone to cache the result.  There's no point in having it hanging
2884                 # around uninitialized in every Title object; therefore we only add it
2885                 # if needed and don't declare it statically.
2886                 if ( isset( $this->mHasSubpages ) ) {
2887                         return $this->mHasSubpages;
2888                 }
2889
2890                 $subpages = $this->getSubpages( 1 );
2891                 if ( $subpages instanceof TitleArray ) {
2892                         return $this->mHasSubpages = (bool)$subpages->count();
2893                 }
2894                 return $this->mHasSubpages = false;
2895         }
2896
2897         /**
2898          * Get all subpages of this page.
2899          *
2900          * @param int $limit maximum number of subpages to fetch; -1 for no limit
2901          * @return mixed TitleArray, or empty array if this page's namespace
2902          *  doesn't allow subpages
2903          */
2904         public function getSubpages( $limit = -1 ) {
2905                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
2906                         return array();
2907                 }
2908
2909                 $dbr = wfGetDB( DB_SLAVE );
2910                 $conds['page_namespace'] = $this->getNamespace();
2911                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
2912                 $options = array();
2913                 if ( $limit > -1 ) {
2914                         $options['LIMIT'] = $limit;
2915                 }
2916                 return $this->mSubpages = TitleArray::newFromResult(
2917                         $dbr->select( 'page',
2918                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
2919                                 $conds,
2920                                 __METHOD__,
2921                                 $options
2922                         )
2923                 );
2924         }
2925
2926         /**
2927          * Is there a version of this page in the deletion archive?
2928          *
2929          * @return Int the number of archived revisions
2930          */
2931         public function isDeleted() {
2932                 if ( $this->getNamespace() < 0 ) {
2933                         $n = 0;
2934                 } else {
2935                         $dbr = wfGetDB( DB_SLAVE );
2936
2937                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
2938                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2939                                 __METHOD__
2940                         );
2941                         if ( $this->getNamespace() == NS_FILE ) {
2942                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
2943                                         array( 'fa_name' => $this->getDBkey() ),
2944                                         __METHOD__
2945                                 );
2946                         }
2947                 }
2948                 return (int)$n;
2949         }
2950
2951         /**
2952          * Is there a version of this page in the deletion archive?
2953          *
2954          * @return Boolean
2955          */
2956         public function isDeletedQuick() {
2957                 if ( $this->getNamespace() < 0 ) {
2958                         return false;
2959                 }
2960                 $dbr = wfGetDB( DB_SLAVE );
2961                 $deleted = (bool)$dbr->selectField( 'archive', '1',
2962                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
2963                         __METHOD__
2964                 );
2965                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
2966                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
2967                                 array( 'fa_name' => $this->getDBkey() ),
2968                                 __METHOD__
2969                         );
2970                 }
2971                 return $deleted;
2972         }
2973
2974         /**
2975          * Get the article ID for this Title from the link cache,
2976          * adding it if necessary
2977          *
2978          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select
2979          *  for update
2980          * @return Int the ID
2981          */
2982         public function getArticleID( $flags = 0 ) {
2983                 if ( $this->getNamespace() < 0 ) {
2984                         return $this->mArticleID = 0;
2985                 }
2986                 $linkCache = LinkCache::singleton();
2987                 if ( $flags & self::GAID_FOR_UPDATE ) {
2988                         $oldUpdate = $linkCache->forUpdate( true );
2989                         $linkCache->clearLink( $this );
2990                         $this->mArticleID = $linkCache->addLinkObj( $this );
2991                         $linkCache->forUpdate( $oldUpdate );
2992                 } else {
2993                         if ( -1 == $this->mArticleID ) {
2994                                 $this->mArticleID = $linkCache->addLinkObj( $this );
2995                         }
2996                 }
2997                 return $this->mArticleID;
2998         }
2999
3000         /**
3001          * Is this an article that is a redirect page?
3002          * Uses link cache, adding it if necessary
3003          *
3004          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3005          * @return Bool
3006          */
3007         public function isRedirect( $flags = 0 ) {
3008                 if ( !is_null( $this->mRedirect ) ) {
3009                         return $this->mRedirect;
3010                 }
3011                 # Calling getArticleID() loads the field from cache as needed
3012                 if ( !$this->getArticleID( $flags ) ) {
3013                         return $this->mRedirect = false;
3014                 }
3015
3016                 $linkCache = LinkCache::singleton();
3017                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3018                 if ( $cached === null ) {
3019                         # Trust LinkCache's state over our own
3020                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3021                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3022                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3023                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3024                         # LinkCache to refresh its data from the master.
3025                         return $this->mRedirect = false;
3026                 }
3027
3028                 $this->mRedirect = (bool)$cached;
3029
3030                 return $this->mRedirect;
3031         }
3032
3033         /**
3034          * What is the length of this page?
3035          * Uses link cache, adding it if necessary
3036          *
3037          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3038          * @return Int
3039          */
3040         public function getLength( $flags = 0 ) {
3041                 if ( $this->mLength != -1 ) {
3042                         return $this->mLength;
3043                 }
3044                 # Calling getArticleID() loads the field from cache as needed
3045                 if ( !$this->getArticleID( $flags ) ) {
3046                         return $this->mLength = 0;
3047                 }
3048                 $linkCache = LinkCache::singleton();
3049                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3050                 if ( $cached === null ) {
3051                         # Trust LinkCache's state over our own, as for isRedirect()
3052                         return $this->mLength = 0;
3053                 }
3054
3055                 $this->mLength = intval( $cached );
3056
3057                 return $this->mLength;
3058         }
3059
3060         /**
3061          * What is the page_latest field for this page?
3062          *
3063          * @param int $flags a bit field; may be Title::GAID_FOR_UPDATE to select for update
3064          * @return Int or 0 if the page doesn't exist
3065          */
3066         public function getLatestRevID( $flags = 0 ) {
3067                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3068                         return intval( $this->mLatestID );
3069                 }
3070                 # Calling getArticleID() loads the field from cache as needed
3071                 if ( !$this->getArticleID( $flags ) ) {
3072                         return $this->mLatestID = 0;
3073                 }
3074                 $linkCache = LinkCache::singleton();
3075                 $linkCache->addLinkObj( $this );
3076                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3077                 if ( $cached === null ) {
3078                         # Trust LinkCache's state over our own, as for isRedirect()
3079                         return $this->mLatestID = 0;
3080                 }
3081
3082                 $this->mLatestID = intval( $cached );
3083
3084                 return $this->mLatestID;
3085         }
3086
3087         /**
3088          * This clears some fields in this object, and clears any associated
3089          * keys in the "bad links" section of the link cache.
3090          *
3091          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3092          * loading of the new page_id. It's also called from
3093          * WikiPage::doDeleteArticleReal()
3094          *
3095          * @param int $newid the new Article ID
3096          */
3097         public function resetArticleID( $newid ) {
3098                 $linkCache = LinkCache::singleton();
3099                 $linkCache->clearLink( $this );
3100
3101                 if ( $newid === false ) {
3102                         $this->mArticleID = -1;
3103                 } else {
3104                         $this->mArticleID = intval( $newid );
3105                 }
3106                 $this->mRestrictionsLoaded = false;
3107                 $this->mRestrictions = array();
3108                 $this->mRedirect = null;
3109                 $this->mLength = -1;
3110                 $this->mLatestID = false;
3111                 $this->mContentModel = false;
3112                 $this->mEstimateRevisions = null;
3113         }
3114
3115         /**
3116          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3117          *
3118          * @param string $text containing title to capitalize
3119          * @param int $ns namespace index, defaults to NS_MAIN
3120          * @return String containing capitalized title
3121          */
3122         public static function capitalize( $text, $ns = NS_MAIN ) {
3123                 global $wgContLang;
3124
3125                 if ( MWNamespace::isCapitalized( $ns ) ) {
3126                         return $wgContLang->ucfirst( $text );
3127                 } else {
3128                         return $text;
3129                 }
3130         }
3131
3132         /**
3133          * Secure and split - main initialisation function for this object
3134          *
3135          * Assumes that mDbkeyform has been set, and is urldecoded
3136          * and uses underscores, but not otherwise munged.  This function
3137          * removes illegal characters, splits off the interwiki and
3138          * namespace prefixes, sets the other forms, and canonicalizes
3139          * everything.
3140          *
3141          * @return Bool true on success
3142          */
3143         private function secureAndSplit() {
3144                 global $wgContLang, $wgLocalInterwiki;
3145
3146                 # Initialisation
3147                 $this->mInterwiki = $this->mFragment = '';
3148                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3149
3150                 $dbkey = $this->mDbkeyform;
3151
3152                 # Strip Unicode bidi override characters.
3153                 # Sometimes they slip into cut-n-pasted page titles, where the
3154                 # override chars get included in list displays.
3155                 $dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );
3156
3157                 # Clean up whitespace
3158                 # Note: use of the /u option on preg_replace here will cause
3159                 # input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
3160                 # conveniently disabling them.
3161                 $dbkey = preg_replace( '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u', '_', $dbkey );
3162                 $dbkey = trim( $dbkey, '_' );
3163
3164                 if ( $dbkey == '' ) {
3165                         return false;
3166                 }
3167
3168                 if ( strpos( $dbkey, UTF8_REPLACEMENT ) !== false ) {
3169                         # Contained illegal UTF-8 sequences or forbidden Unicode chars.
3170                         return false;
3171                 }
3172
3173                 $this->mDbkeyform = $dbkey;
3174
3175                 # Initial colon indicates main namespace rather than specified default
3176                 # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
3177                 if ( ':' == $dbkey[0] ) {
3178                         $this->mNamespace = NS_MAIN;
3179                         $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
3180                         $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
3181                 }
3182
3183                 # Namespace or interwiki prefix
3184                 $firstPass = true;
3185                 $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
3186                 do {
3187                         $m = array();
3188                         if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
3189                                 $p = $m[1];
3190                                 if ( ( $ns = $wgContLang->getNsIndex( $p ) ) !== false ) {
3191                                         # Ordinary namespace
3192                                         $dbkey = $m[2];
3193                                         $this->mNamespace = $ns;
3194                                         # For Talk:X pages, check if X has a "namespace" prefix
3195                                         if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
3196                                                 if ( $wgContLang->getNsIndex( $x[1] ) ) {
3197                                                         # Disallow Talk:File:x type titles...
3198                                                         return false;
3199                                                 } elseif ( Interwiki::isValidInterwiki( $x[1] ) ) {
3200                                                         # Disallow Talk:Interwiki:x type titles...
3201                                                         return false;
3202                                                 }
3203                                         }
3204                                 } elseif ( Interwiki::isValidInterwiki( $p ) ) {
3205                                         if ( !$firstPass ) {
3206                                                 # Can't make a local interwiki link to an interwiki link.
3207                                                 # That's just crazy!
3208                                                 return false;
3209                                         }
3210
3211                                         # Interwiki link
3212                                         $dbkey = $m[2];
3213                                         $this->mInterwiki = $wgContLang->lc( $p );
3214
3215                                         # Redundant interwiki prefix to the local wiki
3216                                         if ( $wgLocalInterwiki !== false
3217                                                 && 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki ) )
3218                                         {
3219                                                 if ( $dbkey == '' ) {
3220                                                         # Can't have an empty self-link
3221                                                         return false;
3222                                                 }
3223                                                 $this->mInterwiki = '';
3224                                                 $firstPass = false;
3225                                                 # Do another namespace split...
3226                                                 continue;
3227                                         }
3228
3229                                         # If there's an initial colon after the interwiki, that also
3230                                         # resets the default namespace
3231                                         if ( $dbkey !== '' && $dbkey[0] == ':' ) {
3232                                                 $this->mNamespace = NS_MAIN;
3233                                                 $dbkey = substr( $dbkey, 1 );
3234                                         }
3235                                 }
3236                                 # If there's no recognized interwiki or namespace,
3237                                 # then let the colon expression be part of the title.
3238                         }
3239                         break;
3240                 } while ( true );
3241
3242                 # We already know that some pages won't be in the database!
3243                 if ( $this->mInterwiki != '' || NS_SPECIAL == $this->mNamespace ) {
3244                         $this->mArticleID = 0;
3245                 }
3246                 $fragment = strstr( $dbkey, '#' );
3247                 if ( false !== $fragment ) {
3248                         $this->setFragment( $fragment );
3249                         $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
3250                         # remove whitespace again: prevents "Foo_bar_#"
3251                         # becoming "Foo_bar_"
3252                         $dbkey = preg_replace( '/_*$/', '', $dbkey );
3253                 }
3254
3255                 # Reject illegal characters.
3256                 $rxTc = self::getTitleInvalidRegex();
3257                 if ( preg_match( $rxTc, $dbkey ) ) {
3258                         return false;
3259                 }
3260
3261                 # Pages with "/./" or "/../" appearing in the URLs will often be un-
3262                 # reachable due to the way web browsers deal with 'relative' URLs.
3263                 # Also, they conflict with subpage syntax.  Forbid them explicitly.
3264                 if (
3265                         strpos( $dbkey, '.' ) !== false &&
3266                         (
3267                                 $dbkey === '.' || $dbkey === '..' ||
3268                                 strpos( $dbkey, './' ) === 0 ||
3269                                 strpos( $dbkey, '../' ) === 0 ||
3270                                 strpos( $dbkey, '/./' ) !== false ||
3271                                 strpos( $dbkey, '/../' ) !== false ||
3272                                 substr( $dbkey, -2 ) == '/.' ||
3273                                 substr( $dbkey, -3 ) == '/..'
3274                         )
3275                 ) {
3276                         return false;
3277                 }
3278
3279                 # Magic tilde sequences? Nu-uh!
3280                 if ( strpos( $dbkey, '~~~' ) !== false ) {
3281                         return false;
3282                 }
3283
3284                 # Limit the size of titles to 255 bytes. This is typically the size of the
3285                 # underlying database field. We make an exception for special pages, which
3286                 # don't need to be stored in the database, and may edge over 255 bytes due
3287                 # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
3288                 if (
3289                         ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 )
3290                         || strlen( $dbkey ) > 512
3291                 ) {
3292                         return false;
3293                 }
3294
3295                 # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
3296                 # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
3297                 # other site might be case-sensitive.
3298                 $this->mUserCaseDBKey = $dbkey;
3299                 if ( $this->mInterwiki == '' ) {
3300                         $dbkey = self::capitalize( $dbkey, $this->mNamespace );
3301                 }
3302
3303                 # Can't make a link to a namespace alone... "empty" local links can only be
3304                 # self-links with a fragment identifier.
3305                 # TODO: Why do we exclude NS_MAIN (bug 54044)
3306                 if ( $dbkey == '' && $this->mInterwiki == '' && $this->mNamespace != NS_MAIN ) {
3307                         return false;
3308                 }
3309
3310                 // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
3311                 // IP names are not allowed for accounts, and can only be referring to
3312                 // edits from the IP. Given '::' abbreviations and caps/lowercaps,
3313                 // there are numerous ways to present the same IP. Having sp:contribs scan
3314                 // them all is silly and having some show the edits and others not is
3315                 // inconsistent. Same for talk/userpages. Keep them normalized instead.
3316                 $dbkey = ( $this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK )
3317                         ? IP::sanitizeIP( $dbkey )
3318                         : $dbkey;
3319
3320                 // Any remaining initial :s are illegal.
3321                 if ( $dbkey !== '' && ':' == $dbkey[0] ) {
3322                         return false;
3323                 }
3324
3325                 # Fill fields
3326                 $this->mDbkeyform = $dbkey;
3327                 $this->mUrlform = wfUrlencode( $dbkey );
3328
3329                 $this->mTextform = str_replace( '_', ' ', $dbkey );
3330
3331                 return true;
3332         }
3333
3334         /**
3335          * Get an array of Title objects linking to this Title
3336          * Also stores the IDs in the link cache.
3337          *
3338          * WARNING: do not use this function on arbitrary user-supplied titles!
3339          * On heavily-used templates it will max out the memory.
3340          *
3341          * @param array $options may be FOR UPDATE
3342          * @param string $table table name
3343          * @param string $prefix fields prefix
3344          * @return Array of Title objects linking here
3345          */
3346         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3347                 if ( count( $options ) > 0 ) {
3348                         $db = wfGetDB( DB_MASTER );
3349                 } else {
3350                         $db = wfGetDB( DB_SLAVE );
3351                 }
3352
3353                 $res = $db->select(
3354                         array( 'page', $table ),
3355                         self::getSelectFields(),
3356                         array(
3357                                 "{$prefix}_from=page_id",
3358                                 "{$prefix}_namespace" => $this->getNamespace(),
3359                                 "{$prefix}_title" => $this->getDBkey() ),
3360                         __METHOD__,
3361                         $options
3362                 );
3363
3364                 $retVal = array();
3365                 if ( $res->numRows() ) {
3366                         $linkCache = LinkCache::singleton();
3367                         foreach ( $res as $row ) {
3368                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3369                                 if ( $titleObj ) {
3370                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3371                                         $retVal[] = $titleObj;
3372                                 }
3373                         }
3374                 }
3375                 return $retVal;
3376         }
3377
3378         /**
3379          * Get an array of Title objects using this Title as a template
3380          * Also stores the IDs in the link cache.
3381          *
3382          * WARNING: do not use this function on arbitrary user-supplied titles!
3383          * On heavily-used templates it will max out the memory.
3384          *
3385          * @param array $options may be FOR UPDATE
3386          * @return Array of Title the Title objects linking here
3387          */
3388         public function getTemplateLinksTo( $options = array() ) {
3389                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3390         }
3391
3392         /**
3393          * Get an array of Title objects linked from this Title
3394          * Also stores the IDs in the link cache.
3395          *
3396          * WARNING: do not use this function on arbitrary user-supplied titles!
3397          * On heavily-used templates it will max out the memory.
3398          *
3399          * @param array $options may be FOR UPDATE
3400          * @param string $table table name
3401          * @param string $prefix fields prefix
3402          * @return Array of Title objects linking here
3403          */
3404         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3405                 global $wgContentHandlerUseDB;
3406
3407                 $id = $this->getArticleID();
3408
3409                 # If the page doesn't exist; there can't be any link from this page
3410                 if ( !$id ) {
3411                         return array();
3412                 }
3413
3414                 if ( count( $options ) > 0 ) {
3415                         $db = wfGetDB( DB_MASTER );
3416                 } else {
3417                         $db = wfGetDB( DB_SLAVE );
3418                 }
3419
3420                 $namespaceFiled = "{$prefix}_namespace";
3421                 $titleField = "{$prefix}_title";
3422
3423                 $fields = array( $namespaceFiled, $titleField, 'page_id', 'page_len', 'page_is_redirect', 'page_latest' );
3424                 if ( $wgContentHandlerUseDB ) {
3425                         $fields[] = 'page_content_model';
3426                 }
3427
3428                 $res = $db->select(
3429                         array( $table, 'page' ),
3430                         $fields,
3431                         array( "{$prefix}_from" => $id ),
3432                         __METHOD__,
3433                         $options,
3434                         array( 'page' => array( 'LEFT JOIN', array( "page_namespace=$namespaceFiled", "page_title=$titleField" ) ) )
3435                 );
3436
3437                 $retVal = array();
3438                 if ( $res->numRows() ) {
3439                         $linkCache = LinkCache::singleton();
3440                         foreach ( $res as $row ) {
3441                                 $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
3442                                 if ( $titleObj ) {
3443                                         if ( $row->page_id ) {
3444                                                 $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3445                                         } else {
3446                                                 $linkCache->addBadLinkObj( $titleObj );
3447                                         }
3448                                         $retVal[] = $titleObj;
3449                                 }
3450                         }
3451                 }
3452                 return $retVal;
3453         }
3454
3455         /**
3456          * Get an array of Title objects used on this Title as a template
3457          * Also stores the IDs in the link cache.
3458          *
3459          * WARNING: do not use this function on arbitrary user-supplied titles!
3460          * On heavily-used templates it will max out the memory.
3461          *
3462          * @param array $options may be FOR UPDATE
3463          * @return Array of Title the Title objects used here
3464          */
3465         public function getTemplateLinksFrom( $options = array() ) {
3466                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3467         }
3468
3469         /**
3470          * Get an array of Title objects referring to non-existent articles linked from this page
3471          *
3472          * @todo check if needed (used only in SpecialBrokenRedirects.php, and should use redirect table in this case)
3473          * @return Array of Title the Title objects
3474          */
3475         public function getBrokenLinksFrom() {
3476                 if ( $this->getArticleID() == 0 ) {
3477                         # All links from article ID 0 are false positives
3478                         return array();
3479                 }
3480
3481                 $dbr = wfGetDB( DB_SLAVE );
3482                 $res = $dbr->select(
3483                         array( 'page', 'pagelinks' ),
3484                         array( 'pl_namespace', 'pl_title' ),
3485                         array(
3486                                 'pl_from' => $this->getArticleID(),
3487                                 'page_namespace IS NULL'
3488                         ),
3489                         __METHOD__, array(),
3490                         array(
3491                                 'page' => array(
3492                                         'LEFT JOIN',
3493                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3494                                 )
3495                         )
3496                 );
3497
3498                 $retVal = array();
3499                 foreach ( $res as $row ) {
3500                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3501                 }
3502                 return $retVal;
3503         }
3504
3505         /**
3506          * Get a list of URLs to purge from the Squid cache when this
3507          * page changes
3508          *
3509          * @return Array of String the URLs
3510          */
3511         public function getSquidURLs() {
3512                 $urls = array(
3513                         $this->getInternalURL(),
3514                         $this->getInternalURL( 'action=history' )
3515                 );
3516
3517                 $pageLang = $this->getPageLanguage();
3518                 if ( $pageLang->hasVariants() ) {
3519                         $variants = $pageLang->getVariants();
3520                         foreach ( $variants as $vCode ) {
3521                                 $urls[] = $this->getInternalURL( '', $vCode );
3522                         }
3523                 }
3524
3525                 wfRunHooks( 'TitleSquidURLs', array( $this, &$urls ) );
3526                 return $urls;
3527         }
3528
3529         /**
3530          * Purge all applicable Squid URLs
3531          */
3532         public function purgeSquid() {
3533                 global $wgUseSquid;
3534                 if ( $wgUseSquid ) {
3535                         $urls = $this->getSquidURLs();
3536                         $u = new SquidUpdate( $urls );
3537                         $u->doUpdate();
3538                 }
3539         }
3540
3541         /**
3542          * Move this page without authentication
3543          *
3544          * @param $nt Title the new page Title
3545          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3546          */
3547         public function moveNoAuth( &$nt ) {
3548                 return $this->moveTo( $nt, false );
3549         }
3550
3551         /**
3552          * Check whether a given move operation would be valid.
3553          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3554          *
3555          * @param $nt Title the new title
3556          * @param bool $auth indicates whether $wgUser's permissions
3557          *  should be checked
3558          * @param string $reason is the log summary of the move, used for spam checking
3559          * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
3560          */
3561         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3562                 global $wgUser, $wgContentHandlerUseDB;
3563
3564                 $errors = array();
3565                 if ( !$nt ) {
3566                         // Normally we'd add this to $errors, but we'll get
3567                         // lots of syntax errors if $nt is not an object
3568                         return array( array( 'badtitletext' ) );
3569                 }
3570                 if ( $this->equals( $nt ) ) {
3571                         $errors[] = array( 'selfmove' );
3572                 }
3573                 if ( !$this->isMovable() ) {
3574                         $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
3575                 }
3576                 if ( $nt->getInterwiki() != '' ) {
3577                         $errors[] = array( 'immobile-target-namespace-iw' );
3578                 }
3579                 if ( !$nt->isMovable() ) {
3580                         $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
3581                 }
3582
3583                 $oldid = $this->getArticleID();
3584                 $newid = $nt->getArticleID();
3585
3586                 if ( strlen( $nt->getDBkey() ) < 1 ) {
3587                         $errors[] = array( 'articleexists' );
3588                 }
3589                 if (
3590                         ( $this->getDBkey() == '' ) ||
3591                         ( !$oldid ) ||
3592                         ( $nt->getDBkey() == '' )
3593                 ) {
3594                         $errors[] = array( 'badarticleerror' );
3595                 }
3596
3597                 // Content model checks
3598                 if ( !$wgContentHandlerUseDB &&
3599                                 $this->getContentModel() !== $nt->getContentModel() ) {
3600                         // can't move a page if that would change the page's content model
3601                         $errors[] = array(
3602                                 'bad-target-model',
3603                                 ContentHandler::getLocalizedName( $this->getContentModel() ),
3604                                 ContentHandler::getLocalizedName( $nt->getContentModel() )
3605                         );
3606                 }
3607
3608                 // Image-specific checks
3609                 if ( $this->getNamespace() == NS_FILE ) {
3610                         $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
3611                 }
3612
3613                 if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
3614                         $errors[] = array( 'nonfile-cannot-move-to-file' );
3615                 }
3616
3617                 if ( $auth ) {
3618                         $errors = wfMergeErrorArrays( $errors,
3619                                 $this->getUserPermissionsErrors( 'move', $wgUser ),
3620                                 $this->getUserPermissionsErrors( 'edit', $wgUser ),
3621                                 $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
3622                                 $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
3623                 }
3624
3625                 $match = EditPage::matchSummarySpamRegex( $reason );
3626                 if ( $match !== false ) {
3627                         // This is kind of lame, won't display nice
3628                         $errors[] = array( 'spamprotectiontext' );
3629                 }
3630
3631                 $err = null;
3632                 if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
3633                         $errors[] = array( 'hookaborted', $err );
3634                 }
3635
3636                 # The move is allowed only if (1) the target doesn't exist, or
3637                 # (2) the target is a redirect to the source, and has no history
3638                 # (so we can undo bad moves right after they're done).
3639
3640                 if ( 0 != $newid ) { # Target exists; check for validity
3641                         if ( !$this->isValidMoveTarget( $nt ) ) {
3642                                 $errors[] = array( 'articleexists' );
3643                         }
3644                 } else {
3645                         $tp = $nt->getTitleProtection();
3646                         $right = $tp['pt_create_perm'];
3647                         if ( $right == 'sysop' ) {
3648                                 $right = 'editprotected'; // B/C
3649                         }
3650                         if ( $right == 'autoconfirmed' ) {
3651                                 $right = 'editsemiprotected'; // B/C
3652                         }
3653                         if ( $tp and !$wgUser->isAllowed( $right ) ) {
3654                                 $errors[] = array( 'cantmove-titleprotected' );
3655                         }
3656                 }
3657                 if ( empty( $errors ) ) {
3658                         return true;
3659                 }
3660                 return $errors;
3661         }
3662
3663         /**
3664          * Check if the requested move target is a valid file move target
3665          * @param Title $nt Target title
3666          * @return array List of errors
3667          */
3668         protected function validateFileMoveOperation( $nt ) {
3669                 global $wgUser;
3670
3671                 $errors = array();
3672
3673                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below
3674
3675                 $file = wfLocalFile( $this );
3676                 if ( $file->exists() ) {
3677                         if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
3678                                 $errors[] = array( 'imageinvalidfilename' );
3679                         }
3680                         if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
3681                                 $errors[] = array( 'imagetypemismatch' );
3682                         }
3683                 }
3684
3685                 if ( $nt->getNamespace() != NS_FILE ) {
3686                         $errors[] = array( 'imagenocrossnamespace' );
3687                         // From here we want to do checks on a file object, so if we can't
3688                         // create one, we must return.
3689                         return $errors;
3690                 }
3691
3692                 // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here
3693
3694                 $destFile = wfLocalFile( $nt );
3695                 if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
3696                         $errors[] = array( 'file-exists-sharedrepo' );
3697                 }
3698
3699                 return $errors;
3700         }
3701
3702         /**
3703          * Move a title to a new location
3704          *
3705          * @param $nt Title the new title
3706          * @param bool $auth indicates whether $wgUser's permissions
3707          *  should be checked
3708          * @param string $reason the reason for the move
3709          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3710          *  Ignored if the user doesn't have the suppressredirect right.
3711          * @return Mixed true on success, getUserPermissionsErrors()-like array on failure
3712          */
3713         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3714                 global $wgUser;
3715                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3716                 if ( is_array( $err ) ) {
3717                         // Auto-block user's IP if the account was "hard" blocked
3718                         $wgUser->spreadAnyEditBlock();
3719                         return $err;
3720                 }
3721                 // Check suppressredirect permission
3722                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3723                         $createRedirect = true;
3724                 }
3725
3726                 wfRunHooks( 'TitleMove', array( $this, $nt, $wgUser ) );
3727
3728                 // If it is a file, move it first.
3729                 // It is done before all other moving stuff is done because it's hard to revert.
3730                 $dbw = wfGetDB( DB_MASTER );
3731                 if ( $this->getNamespace() == NS_FILE ) {
3732                         $file = wfLocalFile( $this );
3733                         if ( $file->exists() ) {
3734                                 $status = $file->move( $nt );
3735                                 if ( !$status->isOk() ) {
3736                                         return $status->getErrorsArray();
3737                                 }
3738                         }
3739                         // Clear RepoGroup process cache
3740                         RepoGroup::singleton()->clearCache( $this );
3741                         RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
3742                 }
3743
3744                 $dbw->begin( __METHOD__ ); # If $file was a LocalFile, its transaction would have closed our own.
3745                 $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
3746                 $protected = $this->isProtected();
3747
3748                 // Do the actual move
3749                 $this->moveToInternal( $nt, $reason, $createRedirect );
3750
3751                 // Refresh the sortkey for this row.  Be careful to avoid resetting
3752                 // cl_timestamp, which may disturb time-based lists on some sites.
3753                 $prefixes = $dbw->select(
3754                         'categorylinks',
3755                         array( 'cl_sortkey_prefix', 'cl_to' ),
3756                         array( 'cl_from' => $pageid ),
3757                         __METHOD__
3758                 );
3759                 foreach ( $prefixes as $prefixRow ) {
3760                         $prefix = $prefixRow->cl_sortkey_prefix;
3761                         $catTo = $prefixRow->cl_to;
3762                         $dbw->update( 'categorylinks',
3763                                 array(
3764                                         'cl_sortkey' => Collation::singleton()->getSortKey(
3765                                                 $nt->getCategorySortkey( $prefix ) ),
3766                                         'cl_timestamp=cl_timestamp' ),
3767                                 array(
3768                                         'cl_from' => $pageid,
3769                                         'cl_to' => $catTo ),
3770                                 __METHOD__
3771                         );
3772                 }
3773
3774                 $redirid = $this->getArticleID();
3775
3776                 if ( $protected ) {
3777                         # Protect the redirect title as the title used to be...
3778                         $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
3779                                 array(
3780                                         'pr_page' => $redirid,
3781                                         'pr_type' => 'pr_type',
3782                                         'pr_level' => 'pr_level',
3783                                         'pr_cascade' => 'pr_cascade',
3784                                         'pr_user' => 'pr_user',
3785                                         'pr_expiry' => 'pr_expiry'
3786                                 ),
3787                                 array( 'pr_page' => $pageid ),
3788                                 __METHOD__,
3789                                 array( 'IGNORE' )
3790                         );
3791                         # Update the protection log
3792                         $log = new LogPage( 'protect' );
3793                         $comment = wfMessage(
3794                                 'prot_1movedto2',
3795                                 $this->getPrefixedText(),
3796                                 $nt->getPrefixedText()
3797                         )->inContentLanguage()->text();
3798                         if ( $reason ) {
3799                                 $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3800                         }
3801                         // @todo FIXME: $params?
3802                         $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ), $wgUser );
3803                 }
3804
3805                 # Update watchlists
3806                 $oldnamespace = MWNamespace::getSubject( $this->getNamespace() );
3807                 $newnamespace = MWNamespace::getSubject( $nt->getNamespace() );
3808                 $oldtitle = $this->getDBkey();
3809                 $newtitle = $nt->getDBkey();
3810
3811                 if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
3812                         WatchedItem::duplicateEntries( $this, $nt );
3813                 }
3814
3815                 $dbw->commit( __METHOD__ );
3816
3817                 wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
3818                 return true;
3819         }
3820
3821         /**
3822          * Move page to a title which is either a redirect to the
3823          * source page or nonexistent
3824          *
3825          * @param $nt Title the page to move to, which should be a redirect or nonexistent
3826          * @param string $reason The reason for the move
3827          * @param bool $createRedirect Whether to leave a redirect at the old title. Does not check
3828          *   if the user has the suppressredirect right
3829          * @throws MWException
3830          */
3831         private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
3832                 global $wgUser, $wgContLang;
3833
3834                 if ( $nt->exists() ) {
3835                         $moveOverRedirect = true;
3836                         $logType = 'move_redir';
3837                 } else {
3838                         $moveOverRedirect = false;
3839                         $logType = 'move';
3840                 }
3841
3842                 if ( $createRedirect ) {
3843                         $contentHandler = ContentHandler::getForTitle( $this );
3844                         $redirectContent = $contentHandler->makeRedirectContent( $nt,
3845                                 wfMessage( 'move-redirect-text' )->inContentLanguage()->plain() );
3846
3847                         // NOTE: If this page's content model does not support redirects, $redirectContent will be null.
3848                 } else {
3849                         $redirectContent = null;
3850                 }
3851
3852                 $logEntry = new ManualLogEntry( 'move', $logType );
3853                 $logEntry->setPerformer( $wgUser );
3854                 $logEntry->setTarget( $this );
3855                 $logEntry->setComment( $reason );
3856                 $logEntry->setParameters( array(
3857                         '4::target' => $nt->getPrefixedText(),
3858                         '5::noredir' => $redirectContent ? '0': '1',
3859                 ) );
3860
3861                 $formatter = LogFormatter::newFromEntry( $logEntry );
3862                 $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
3863                 $comment = $formatter->getPlainActionText();
3864                 if ( $reason ) {
3865                         $comment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
3866                 }
3867                 # Truncate for whole multibyte characters.
3868                 $comment = $wgContLang->truncate( $comment, 255 );
3869
3870                 $oldid = $this->getArticleID();
3871
3872                 $dbw = wfGetDB( DB_MASTER );
3873
3874                 $newpage = WikiPage::factory( $nt );
3875
3876                 if ( $moveOverRedirect ) {
3877                         $newid = $nt->getArticleID();
3878
3879                         # Delete the old redirect. We don't save it to history since
3880                         # by definition if we've got here it's rather uninteresting.
3881                         # We have to remove it so that the next step doesn't trigger
3882                         # a conflict on the unique namespace+title index...
3883                         $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );
3884
3885                         $newpage->doDeleteUpdates( $newid );
3886                 }
3887
3888                 # Save a null revision in the page's history notifying of the move
3889                 $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
3890                 if ( !is_object( $nullRevision ) ) {
3891                         throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
3892                 }
3893
3894                 $nullRevision->insertOn( $dbw );
3895
3896                 # Change the name of the target page:
3897                 $dbw->update( 'page',
3898                         /* SET */ array(
3899                                 'page_namespace' => $nt->getNamespace(),
3900                                 'page_title' => $nt->getDBkey(),
3901                         ),
3902                         /* WHERE */ array( 'page_id' => $oldid ),
3903                         __METHOD__
3904                 );
3905
3906                 $this->resetArticleID( 0 );
3907                 $nt->resetArticleID( $oldid );
3908                 $newpage->loadPageData( WikiPage::READ_LOCKING ); // bug 46397
3909
3910                 $newpage->updateRevisionOn( $dbw, $nullRevision );
3911
3912                 wfRunHooks( 'NewRevisionFromEditComplete',
3913                         array( $newpage, $nullRevision, $nullRevision->getParentId(), $wgUser ) );
3914
3915                 $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );
3916
3917                 if ( !$moveOverRedirect ) {
3918                         WikiPage::onArticleCreate( $nt );
3919                 }
3920
3921                 # Recreate the redirect, this time in the other direction.
3922                 if ( !$redirectContent ) {
3923                         WikiPage::onArticleDelete( $this );
3924                 } else {
3925                         $redirectArticle = WikiPage::factory( $this );
3926                         $redirectArticle->loadFromRow( false, WikiPage::READ_LOCKING ); // bug 46397
3927                         $newid = $redirectArticle->insertOn( $dbw );
3928                         if ( $newid ) { // sanity
3929                                 $redirectRevision = new Revision( array(
3930                                         'title' => $this, // for determining the default content model
3931                                         'page' => $newid,
3932                                         'comment' => $comment,
3933                                         'content' => $redirectContent ) );
3934                                 $redirectRevision->insertOn( $dbw );
3935                                 $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
3936
3937                                 wfRunHooks( 'NewRevisionFromEditComplete',
3938                                         array( $redirectArticle, $redirectRevision, false, $wgUser ) );
3939
3940                                 $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
3941                         }
3942                 }
3943
3944                 # Log the move
3945                 $logid = $logEntry->insert();
3946                 $logEntry->publish( $logid );
3947         }
3948
3949         /**
3950          * Move this page's subpages to be subpages of $nt
3951          *
3952          * @param $nt Title Move target
3953          * @param bool $auth Whether $wgUser's permissions should be checked
3954          * @param string $reason The reason for the move
3955          * @param bool $createRedirect Whether to create redirects from the old subpages to
3956          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3957          * @return mixed array with old page titles as keys, and strings (new page titles) or
3958          *     arrays (errors) as values, or an error array with numeric indices if no pages
3959          *     were moved
3960          */
3961         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3962                 global $wgMaximumMovedPages;
3963                 // Check permissions
3964                 if ( !$this->userCan( 'move-subpages' ) ) {
3965                         return array( 'cant-move-subpages' );
3966                 }
3967                 // Do the source and target namespaces support subpages?
3968                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3969                         return array( 'namespace-nosubpages',
3970                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3971                 }
3972                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3973                         return array( 'namespace-nosubpages',
3974                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3975                 }
3976
3977                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3978                 $retval = array();
3979                 $count = 0;
3980                 foreach ( $subpages as $oldSubpage ) {
3981                         $count++;
3982                         if ( $count > $wgMaximumMovedPages ) {
3983                                 $retval[$oldSubpage->getPrefixedTitle()] =
3984                                                 array( 'movepage-max-pages',
3985                                                         $wgMaximumMovedPages );
3986                                 break;
3987                         }
3988
3989                         // We don't know whether this function was called before
3990                         // or after moving the root page, so check both
3991                         // $this and $nt
3992                         if ( $oldSubpage->getArticleID() == $this->getArticleID() ||
3993                                         $oldSubpage->getArticleID() == $nt->getArticleID() )
3994                         {
3995                                 // When moving a page to a subpage of itself,
3996                                 // don't move it twice
3997                                 continue;
3998                         }
3999                         $newPageName = preg_replace(
4000                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
4001                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
4002                                         $oldSubpage->getDBkey() );
4003                         if ( $oldSubpage->isTalkPage() ) {
4004                                 $newNs = $nt->getTalkPage()->getNamespace();
4005                         } else {
4006                                 $newNs = $nt->getSubjectPage()->getNamespace();
4007                         }
4008                         # Bug 14385: we need makeTitleSafe because the new page names may
4009                         # be longer than 255 characters.
4010                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
4011
4012                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
4013                         if ( $success === true ) {
4014                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
4015                         } else {
4016                                 $retval[$oldSubpage->getPrefixedText()] = $success;
4017                         }
4018                 }
4019                 return $retval;
4020         }
4021
4022         /**
4023          * Checks if this page is just a one-rev redirect.
4024          * Adds lock, so don't use just for light purposes.
4025          *
4026          * @return Bool
4027          */
4028         public function isSingleRevRedirect() {
4029                 global $wgContentHandlerUseDB;
4030
4031                 $dbw = wfGetDB( DB_MASTER );
4032
4033                 # Is it a redirect?
4034                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
4035                 if ( $wgContentHandlerUseDB ) {
4036                         $fields[] = 'page_content_model';
4037                 }
4038
4039                 $row = $dbw->selectRow( 'page',
4040                         $fields,
4041                         $this->pageCond(),
4042                         __METHOD__,
4043                         array( 'FOR UPDATE' )
4044                 );
4045                 # Cache some fields we may want
4046                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
4047                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
4048                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
4049                 $this->mContentModel = $row && isset( $row->page_content_model ) ? strval( $row->page_content_model ) : false;
4050                 if ( !$this->mRedirect ) {
4051                         return false;
4052                 }
4053                 # Does the article have a history?
4054                 $row = $dbw->selectField( array( 'page', 'revision' ),
4055                         'rev_id',
4056                         array( 'page_namespace' => $this->getNamespace(),
4057                                 'page_title' => $this->getDBkey(),
4058                                 'page_id=rev_page',
4059                                 'page_latest != rev_id'
4060                         ),
4061                         __METHOD__,
4062                         array( 'FOR UPDATE' )
4063                 );
4064                 # Return true if there was no history
4065                 return ( $row === false );
4066         }
4067
4068         /**
4069          * Checks if $this can be moved to a given Title
4070          * - Selects for update, so don't call it unless you mean business
4071          *
4072          * @param $nt Title the new title to check
4073          * @return Bool
4074          */
4075         public function isValidMoveTarget( $nt ) {
4076                 # Is it an existing file?
4077                 if ( $nt->getNamespace() == NS_FILE ) {
4078                         $file = wfLocalFile( $nt );
4079                         if ( $file->exists() ) {
4080                                 wfDebug( __METHOD__ . ": file exists\n" );
4081                                 return false;
4082                         }
4083                 }
4084                 # Is it a redirect with no history?
4085                 if ( !$nt->isSingleRevRedirect() ) {
4086                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
4087                         return false;
4088                 }
4089                 # Get the article text
4090                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
4091                 if ( !is_object( $rev ) ) {
4092                         return false;
4093                 }
4094                 $content = $rev->getContent();
4095                 # Does the redirect point to the source?
4096                 # Or is it a broken self-redirect, usually caused by namespace collisions?
4097                 $redirTitle = $content ? $content->getRedirectTarget() : null;
4098
4099                 if ( $redirTitle ) {
4100                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
4101                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
4102                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
4103                                 return false;
4104                         } else {
4105                                 return true;
4106                         }
4107                 } else {
4108                         # Fail safe (not a redirect after all. strange.)
4109                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
4110                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
4111                         return false;
4112                 }
4113         }
4114
4115         /**
4116          * Get categories to which this Title belongs and return an array of
4117          * categories' names.
4118          *
4119          * @return Array of parents in the form:
4120          *        $parent => $currentarticle
4121          */
4122         public function getParentCategories() {
4123                 global $wgContLang;
4124
4125                 $data = array();
4126
4127                 $titleKey = $this->getArticleID();
4128
4129                 if ( $titleKey === 0 ) {
4130                         return $data;
4131                 }
4132
4133                 $dbr = wfGetDB( DB_SLAVE );
4134
4135                 $res = $dbr->select(
4136                         'categorylinks',
4137                         'cl_to',
4138                         array( 'cl_from' => $titleKey ),
4139                         __METHOD__
4140                 );
4141
4142                 if ( $res->numRows() > 0 ) {
4143                         foreach ( $res as $row ) {
4144                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
4145                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
4146                         }
4147                 }
4148                 return $data;
4149         }
4150
4151         /**
4152          * Get a tree of parent categories
4153          *
4154          * @param array $children with the children in the keys, to check for circular refs
4155          * @return Array Tree of parent categories
4156          */
4157         public function getParentCategoryTree( $children = array() ) {
4158                 $stack = array();
4159                 $parents = $this->getParentCategories();
4160
4161                 if ( $parents ) {
4162                         foreach ( $parents as $parent => $current ) {
4163                                 if ( array_key_exists( $parent, $children ) ) {
4164                                         # Circular reference
4165                                         $stack[$parent] = array();
4166                                 } else {
4167                                         $nt = Title::newFromText( $parent );
4168                                         if ( $nt ) {
4169                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
4170                                         }
4171                                 }
4172                         }
4173                 }
4174
4175                 return $stack;
4176         }
4177
4178         /**
4179          * Get an associative array for selecting this title from
4180          * the "page" table
4181          *
4182          * @return Array suitable for the $where parameter of DB::select()
4183          */
4184         public function pageCond() {
4185                 if ( $this->mArticleID > 0 ) {
4186                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
4187                         return array( 'page_id' => $this->mArticleID );
4188                 } else {
4189                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
4190                 }
4191         }
4192
4193         /**
4194          * Get the revision ID of the previous revision
4195          *
4196          * @param int $revId Revision ID. Get the revision that was before this one.
4197          * @param int $flags Title::GAID_FOR_UPDATE
4198          * @return Int|Bool Old revision ID, or FALSE if none exists
4199          */
4200         public function getPreviousRevisionID( $revId, $flags = 0 ) {
4201                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4202                 $revId = $db->selectField( 'revision', 'rev_id',
4203                         array(
4204                                 'rev_page' => $this->getArticleID( $flags ),
4205                                 'rev_id < ' . intval( $revId )
4206                         ),
4207                         __METHOD__,
4208                         array( 'ORDER BY' => 'rev_id DESC' )
4209                 );
4210
4211                 if ( $revId === false ) {
4212                         return false;
4213                 } else {
4214                         return intval( $revId );
4215                 }
4216         }
4217
4218         /**
4219          * Get the revision ID of the next revision
4220          *
4221          * @param int $revId Revision ID. Get the revision that was after this one.
4222          * @param int $flags Title::GAID_FOR_UPDATE
4223          * @return Int|Bool Next revision ID, or FALSE if none exists
4224          */
4225         public function getNextRevisionID( $revId, $flags = 0 ) {
4226                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4227                 $revId = $db->selectField( 'revision', 'rev_id',
4228                         array(
4229                                 'rev_page' => $this->getArticleID( $flags ),
4230                                 'rev_id > ' . intval( $revId )
4231                         ),
4232                         __METHOD__,
4233                         array( 'ORDER BY' => 'rev_id' )
4234                 );
4235
4236                 if ( $revId === false ) {
4237                         return false;
4238                 } else {
4239                         return intval( $revId );
4240                 }
4241         }
4242
4243         /**
4244          * Get the first revision of the page
4245          *
4246          * @param int $flags Title::GAID_FOR_UPDATE
4247          * @return Revision|Null if page doesn't exist
4248          */
4249         public function getFirstRevision( $flags = 0 ) {
4250                 $pageId = $this->getArticleID( $flags );
4251                 if ( $pageId ) {
4252                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4253                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4254                                 array( 'rev_page' => $pageId ),
4255                                 __METHOD__,
4256                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4257                         );
4258                         if ( $row ) {
4259                                 return new Revision( $row );
4260                         }
4261                 }
4262                 return null;
4263         }
4264
4265         /**
4266          * Get the oldest revision timestamp of this page
4267          *
4268          * @param int $flags Title::GAID_FOR_UPDATE
4269          * @return String: MW timestamp
4270          */
4271         public function getEarliestRevTime( $flags = 0 ) {
4272                 $rev = $this->getFirstRevision( $flags );
4273                 return $rev ? $rev->getTimestamp() : null;
4274         }
4275
4276         /**
4277          * Check if this is a new page
4278          *
4279          * @return bool
4280          */
4281         public function isNewPage() {
4282                 $dbr = wfGetDB( DB_SLAVE );
4283                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4284         }
4285
4286         /**
4287          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4288          *
4289          * @return bool
4290          */
4291         public function isBigDeletion() {
4292                 global $wgDeleteRevisionsLimit;
4293
4294                 if ( !$wgDeleteRevisionsLimit ) {
4295                         return false;
4296                 }
4297
4298                 $revCount = $this->estimateRevisionCount();
4299                 return $revCount > $wgDeleteRevisionsLimit;
4300         }
4301
4302         /**
4303          * Get the  approximate revision count of this page.
4304          *
4305          * @return int
4306          */
4307         public function estimateRevisionCount() {
4308                 if ( !$this->exists() ) {
4309                         return 0;
4310                 }
4311
4312                 if ( $this->mEstimateRevisions === null ) {
4313                         $dbr = wfGetDB( DB_SLAVE );
4314                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4315                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4316                 }
4317
4318                 return $this->mEstimateRevisions;
4319         }
4320
4321         /**
4322          * Get the number of revisions between the given revision.
4323          * Used for diffs and other things that really need it.
4324          *
4325          * @param int|Revision $old Old revision or rev ID (first before range)
4326          * @param int|Revision $new New revision or rev ID (first after range)
4327          * @return Int Number of revisions between these revisions.
4328          */
4329         public function countRevisionsBetween( $old, $new ) {
4330                 if ( !( $old instanceof Revision ) ) {
4331                         $old = Revision::newFromTitle( $this, (int)$old );
4332                 }
4333                 if ( !( $new instanceof Revision ) ) {
4334                         $new = Revision::newFromTitle( $this, (int)$new );
4335                 }
4336                 if ( !$old || !$new ) {
4337                         return 0; // nothing to compare
4338                 }
4339                 $dbr = wfGetDB( DB_SLAVE );
4340                 return (int)$dbr->selectField( 'revision', 'count(*)',
4341                         array(
4342                                 'rev_page' => $this->getArticleID(),
4343                                 'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4344                                 'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4345                         ),
4346                         __METHOD__
4347                 );
4348         }
4349
4350         /**
4351          * Get the number of authors between the given revisions or revision IDs.
4352          * Used for diffs and other things that really need it.
4353          *
4354          * @param int|Revision $old Old revision or rev ID (first before range by default)
4355          * @param int|Revision $new New revision or rev ID (first after range by default)
4356          * @param int $limit Maximum number of authors
4357          * @param string|array $options (Optional): Single option, or an array of options:
4358          *     'include_old' Include $old in the range; $new is excluded.
4359          *     'include_new' Include $new in the range; $old is excluded.
4360          *     'include_both' Include both $old and $new in the range.
4361          *     Unknown option values are ignored.
4362          * @return int Number of revision authors in the range; zero if not both revisions exist
4363          */
4364         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4365                 if ( !( $old instanceof Revision ) ) {
4366                         $old = Revision::newFromTitle( $this, (int)$old );
4367                 }
4368                 if ( !( $new instanceof Revision ) ) {
4369                         $new = Revision::newFromTitle( $this, (int)$new );
4370                 }
4371                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4372                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4373                 // in the sanity check below?
4374                 if ( !$old || !$new ) {
4375                         return 0; // nothing to compare
4376                 }
4377                 $old_cmp = '>';
4378                 $new_cmp = '<';
4379                 $options = (array)$options;
4380                 if ( in_array( 'include_old', $options ) ) {
4381                         $old_cmp = '>=';
4382                 }
4383                 if ( in_array( 'include_new', $options ) ) {
4384                         $new_cmp = '<=';
4385                 }
4386                 if ( in_array( 'include_both', $options ) ) {
4387                         $old_cmp = '>=';
4388                         $new_cmp = '<=';
4389                 }
4390                 // No DB query needed if $old and $new are the same or successive revisions:
4391                 if ( $old->getId() === $new->getId() ) {
4392                         return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4393                 } elseif ( $old->getId() === $new->getParentId() ) {
4394                         if ( $old_cmp === '>' || $new_cmp === '<' ) {
4395                                 return ( $old_cmp === '>' && $new_cmp === '<' ) ? 0 : 1;
4396                         }
4397                         return ( $old->getRawUserText() === $new->getRawUserText() ) ? 1 : 2;
4398                 }
4399                 $dbr = wfGetDB( DB_SLAVE );
4400                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4401                         array(
4402                                 'rev_page' => $this->getArticleID(),
4403                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4404                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4405                         ), __METHOD__,
4406                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4407                 );
4408                 return (int)$dbr->numRows( $res );
4409         }
4410
4411         /**
4412          * Compare with another title.
4413          *
4414          * @param $title Title
4415          * @return Bool
4416          */
4417         public function equals( Title $title ) {
4418                 // Note: === is necessary for proper matching of number-like titles.
4419                 return $this->getInterwiki() === $title->getInterwiki()
4420                         && $this->getNamespace() == $title->getNamespace()
4421                         && $this->getDBkey() === $title->getDBkey();
4422         }
4423
4424         /**
4425          * Check if this title is a subpage of another title
4426          *
4427          * @param $title Title
4428          * @return Bool
4429          */
4430         public function isSubpageOf( Title $title ) {
4431                 return $this->getInterwiki() === $title->getInterwiki()
4432                         && $this->getNamespace() == $title->getNamespace()
4433                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4434         }
4435
4436         /**
4437          * Check if page exists.  For historical reasons, this function simply
4438          * checks for the existence of the title in the page table, and will
4439          * thus return false for interwiki links, special pages and the like.
4440          * If you want to know if a title can be meaningfully viewed, you should
4441          * probably call the isKnown() method instead.
4442          *
4443          * @return Bool
4444          */
4445         public function exists() {
4446                 return $this->getArticleID() != 0;
4447         }
4448
4449         /**
4450          * Should links to this title be shown as potentially viewable (i.e. as
4451          * "bluelinks"), even if there's no record by this title in the page
4452          * table?
4453          *
4454          * This function is semi-deprecated for public use, as well as somewhat
4455          * misleadingly named.  You probably just want to call isKnown(), which
4456          * calls this function internally.
4457          *
4458          * (ISSUE: Most of these checks are cheap, but the file existence check
4459          * can potentially be quite expensive.  Including it here fixes a lot of
4460          * existing code, but we might want to add an optional parameter to skip
4461          * it and any other expensive checks.)
4462          *
4463          * @return Bool
4464          */
4465         public function isAlwaysKnown() {
4466                 $isKnown = null;
4467
4468                 /**
4469                  * Allows overriding default behavior for determining if a page exists.
4470                  * If $isKnown is kept as null, regular checks happen. If it's
4471                  * a boolean, this value is returned by the isKnown method.
4472                  *
4473                  * @since 1.20
4474                  *
4475                  * @param Title $title
4476                  * @param boolean|null $isKnown
4477                  */
4478                 wfRunHooks( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4479
4480                 if ( !is_null( $isKnown ) ) {
4481                         return $isKnown;
4482                 }
4483
4484                 if ( $this->mInterwiki != '' ) {
4485                         return true;  // any interwiki link might be viewable, for all we know
4486                 }
4487
4488                 switch ( $this->mNamespace ) {
4489                         case NS_MEDIA:
4490                         case NS_FILE:
4491                                 // file exists, possibly in a foreign repo
4492                                 return (bool)wfFindFile( $this );
4493                         case NS_SPECIAL:
4494                                 // valid special page
4495                                 return SpecialPageFactory::exists( $this->getDBkey() );
4496                         case NS_MAIN:
4497                                 // selflink, possibly with fragment
4498                                 return $this->mDbkeyform == '';
4499                         case NS_MEDIAWIKI:
4500                                 // known system message
4501                                 return $this->hasSourceText() !== false;
4502                         default:
4503                                 return false;
4504                 }
4505         }
4506
4507         /**
4508          * Does this title refer to a page that can (or might) be meaningfully
4509          * viewed?  In particular, this function may be used to determine if
4510          * links to the title should be rendered as "bluelinks" (as opposed to
4511          * "redlinks" to non-existent pages).
4512          * Adding something else to this function will cause inconsistency
4513          * since LinkHolderArray calls isAlwaysKnown() and does its own
4514          * page existence check.
4515          *
4516          * @return Bool
4517          */
4518         public function isKnown() {
4519                 return $this->isAlwaysKnown() || $this->exists();
4520         }
4521
4522         /**
4523          * Does this page have source text?
4524          *
4525          * @return Boolean
4526          */
4527         public function hasSourceText() {
4528                 if ( $this->exists() ) {
4529                         return true;
4530                 }
4531
4532                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4533                         // If the page doesn't exist but is a known system message, default
4534                         // message content will be displayed, same for language subpages-
4535                         // Use always content language to avoid loading hundreds of languages
4536                         // to get the link color.
4537                         global $wgContLang;
4538                         list( $name, ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4539                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4540                         return $message->exists();
4541                 }
4542
4543                 return false;
4544         }
4545
4546         /**
4547          * Get the default message text or false if the message doesn't exist
4548          *
4549          * @return String or false
4550          */
4551         public function getDefaultMessageText() {
4552                 global $wgContLang;
4553
4554                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4555                         return false;
4556                 }
4557
4558                 list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
4559                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4560
4561                 if ( $message->exists() ) {
4562                         return $message->plain();
4563                 } else {
4564                         return false;
4565                 }
4566         }
4567
4568         /**
4569          * Updates page_touched for this page; called from LinksUpdate.php
4570          *
4571          * @return Bool true if the update succeeded
4572          */
4573         public function invalidateCache() {
4574                 if ( wfReadOnly() ) {
4575                         return false;
4576                 }
4577
4578                 $method = __METHOD__;
4579                 $dbw = wfGetDB( DB_MASTER );
4580                 $conds = $this->pageCond();
4581                 $dbw->onTransactionIdle( function() use ( $dbw, $conds, $method ) {
4582                         $dbw->update(
4583                                 'page',
4584                                 array( 'page_touched' => $dbw->timestamp() ),
4585                                 $conds,
4586                                 $method
4587                         );
4588                 } );
4589
4590                 return true;
4591         }
4592
4593         /**
4594          * Update page_touched timestamps and send squid purge messages for
4595          * pages linking to this title. May be sent to the job queue depending
4596          * on the number of links. Typically called on create and delete.
4597          */
4598         public function touchLinks() {
4599                 $u = new HTMLCacheUpdate( $this, 'pagelinks' );
4600                 $u->doUpdate();
4601
4602                 if ( $this->getNamespace() == NS_CATEGORY ) {
4603                         $u = new HTMLCacheUpdate( $this, 'categorylinks' );
4604                         $u->doUpdate();
4605                 }
4606         }
4607
4608         /**
4609          * Get the last touched timestamp
4610          *
4611          * @param $db DatabaseBase: optional db
4612          * @return String last-touched timestamp
4613          */
4614         public function getTouched( $db = null ) {
4615                 $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
4616                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4617                 return $touched;
4618         }
4619
4620         /**
4621          * Get the timestamp when this page was updated since the user last saw it.
4622          *
4623          * @param $user User
4624          * @return String|Null
4625          */
4626         public function getNotificationTimestamp( $user = null ) {
4627                 global $wgUser, $wgShowUpdatedMarker;
4628                 // Assume current user if none given
4629                 if ( !$user ) {
4630                         $user = $wgUser;
4631                 }
4632                 // Check cache first
4633                 $uid = $user->getId();
4634                 // avoid isset here, as it'll return false for null entries
4635                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4636                         return $this->mNotificationTimestamp[$uid];
4637                 }
4638                 if ( !$uid || !$wgShowUpdatedMarker || !$user->isAllowed( 'viewmywatchlist' ) ) {
4639                         return $this->mNotificationTimestamp[$uid] = false;
4640                 }
4641                 // Don't cache too much!
4642                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4643                         $this->mNotificationTimestamp = array();
4644                 }
4645                 $dbr = wfGetDB( DB_SLAVE );
4646                 $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
4647                         'wl_notificationtimestamp',
4648                         array(
4649                                 'wl_user' => $user->getId(),
4650                                 'wl_namespace' => $this->getNamespace(),
4651                                 'wl_title' => $this->getDBkey(),
4652                         ),
4653                         __METHOD__
4654                 );
4655                 return $this->mNotificationTimestamp[$uid];
4656         }
4657
4658         /**
4659          * Generate strings used for xml 'id' names in monobook tabs
4660          *
4661          * @param string $prepend defaults to 'nstab-'
4662          * @return String XML 'id' name
4663          */
4664         public function getNamespaceKey( $prepend = 'nstab-' ) {
4665                 global $wgContLang;
4666                 // Gets the subject namespace if this title
4667                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4668                 // Checks if canonical namespace name exists for namespace
4669                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4670                         // Uses canonical namespace name
4671                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4672                 } else {
4673                         // Uses text of namespace
4674                         $namespaceKey = $this->getSubjectNsText();
4675                 }
4676                 // Makes namespace key lowercase
4677                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4678                 // Uses main
4679                 if ( $namespaceKey == '' ) {
4680                         $namespaceKey = 'main';
4681                 }
4682                 // Changes file to image for backwards compatibility
4683                 if ( $namespaceKey == 'file' ) {
4684                         $namespaceKey = 'image';
4685                 }
4686                 return $prepend . $namespaceKey;
4687         }
4688
4689         /**
4690          * Get all extant redirects to this Title
4691          *
4692          * @param int|Null $ns Single namespace to consider; NULL to consider all namespaces
4693          * @return Array of Title redirects to this title
4694          */
4695         public function getRedirectsHere( $ns = null ) {
4696                 $redirs = array();
4697
4698                 $dbr = wfGetDB( DB_SLAVE );
4699                 $where = array(
4700                         'rd_namespace' => $this->getNamespace(),
4701                         'rd_title' => $this->getDBkey(),
4702                         'rd_from = page_id'
4703                 );
4704                 if ( $this->isExternal() ) {
4705                         $where['rd_interwiki'] = $this->getInterwiki();
4706                 } else {
4707                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4708                 }
4709                 if ( !is_null( $ns ) ) {
4710                         $where['page_namespace'] = $ns;
4711                 }
4712
4713                 $res = $dbr->select(
4714                         array( 'redirect', 'page' ),
4715                         array( 'page_namespace', 'page_title' ),
4716                         $where,
4717                         __METHOD__
4718                 );
4719
4720                 foreach ( $res as $row ) {
4721                         $redirs[] = self::newFromRow( $row );
4722                 }
4723                 return $redirs;
4724         }
4725
4726         /**
4727          * Check if this Title is a valid redirect target
4728          *
4729          * @return Bool
4730          */
4731         public function isValidRedirectTarget() {
4732                 global $wgInvalidRedirectTargets;
4733
4734                 // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4735                 if ( $this->isSpecial( 'Userlogout' ) ) {
4736                         return false;
4737                 }
4738
4739                 foreach ( $wgInvalidRedirectTargets as $target ) {
4740                         if ( $this->isSpecial( $target ) ) {
4741                                 return false;
4742                         }
4743                 }
4744
4745                 return true;
4746         }
4747
4748         /**
4749          * Get a backlink cache object
4750          *
4751          * @return BacklinkCache
4752          */
4753         public function getBacklinkCache() {
4754                 return BacklinkCache::get( $this );
4755         }
4756
4757         /**
4758          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4759          *
4760          * @return Boolean
4761          */
4762         public function canUseNoindex() {
4763                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4764
4765                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4766                         ? $wgContentNamespaces
4767                         : $wgExemptFromUserRobotsControl;
4768
4769                 return !in_array( $this->mNamespace, $bannedNamespaces );
4770
4771         }
4772
4773         /**
4774          * Returns the raw sort key to be used for categories, with the specified
4775          * prefix.  This will be fed to Collation::getSortKey() to get a
4776          * binary sortkey that can be used for actual sorting.
4777          *
4778          * @param string $prefix The prefix to be used, specified using
4779          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4780          *   prefix.
4781          * @return string
4782          */
4783         public function getCategorySortkey( $prefix = '' ) {
4784                 $unprefixed = $this->getText();
4785
4786                 // Anything that uses this hook should only depend
4787                 // on the Title object passed in, and should probably
4788                 // tell the users to run updateCollations.php --force
4789                 // in order to re-sort existing category relations.
4790                 wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4791                 if ( $prefix !== '' ) {
4792                         # Separate with a line feed, so the unprefixed part is only used as
4793                         # a tiebreaker when two pages have the exact same prefix.
4794                         # In UCA, tab is the only character that can sort above LF
4795                         # so we strip both of them from the original prefix.
4796                         $prefix = strtr( $prefix, "\n\t", '  ' );
4797                         return "$prefix\n$unprefixed";
4798                 }
4799                 return $unprefixed;
4800         }
4801
4802         /**
4803          * Get the language in which the content of this page is written in
4804          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4805          * e.g. $wgLang (such as special pages, which are in the user language).
4806          *
4807          * @since 1.18
4808          * @return Language
4809          */
4810         public function getPageLanguage() {
4811                 global $wgLang;
4812                 if ( $this->isSpecialPage() ) {
4813                         // special pages are in the user language
4814                         return $wgLang;
4815                 }
4816
4817                 //TODO: use the LinkCache to cache this! Note that this may depend on user settings, so the cache should be only per-request.
4818                 //NOTE: ContentHandler::getPageLanguage() may need to load the content to determine the page language!
4819                 $contentHandler = ContentHandler::getForTitle( $this );
4820                 $pageLang = $contentHandler->getPageLanguage( $this );
4821
4822                 return wfGetLangObj( $pageLang );
4823         }
4824
4825         /**
4826          * Get the language in which the content of this page is written when
4827          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4828          * e.g. $wgLang (such as special pages, which are in the user language).
4829          *
4830          * @since 1.20
4831          * @return Language
4832          */
4833         public function getPageViewLanguage() {
4834                 global $wgLang;
4835
4836                 if ( $this->isSpecialPage() ) {
4837                         // If the user chooses a variant, the content is actually
4838                         // in a language whose code is the variant code.
4839                         $variant = $wgLang->getPreferredVariant();
4840                         if ( $wgLang->getCode() !== $variant ) {
4841                                 return Language::factory( $variant );
4842                         }
4843
4844                         return $wgLang;
4845                 }
4846
4847                 //NOTE: can't be cached persistently, depends on user settings
4848                 //NOTE: ContentHandler::getPageViewLanguage() may need to load the content to determine the page language!
4849                 $contentHandler = ContentHandler::getForTitle( $this );
4850                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4851                 return $pageLang;
4852         }
4853
4854         /**
4855          * Get a list of rendered edit notices for this page.
4856          *
4857          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4858          * they will already be wrapped in paragraphs.
4859          *
4860          * @since 1.21
4861          * @param int oldid Revision ID that's being edited
4862          * @return Array
4863          */
4864         public function getEditNotices( $oldid = 0 ) {
4865                 $notices = array();
4866
4867                 # Optional notices on a per-namespace and per-page basis
4868                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4869                 $editnotice_ns_message = wfMessage( $editnotice_ns );
4870                 if ( $editnotice_ns_message->exists() ) {
4871                         $notices[$editnotice_ns] = $editnotice_ns_message->parseAsBlock();
4872                 }
4873                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4874                         $parts = explode( '/', $this->getDBkey() );
4875                         $editnotice_base = $editnotice_ns;
4876                         while ( count( $parts ) > 0 ) {
4877                                 $editnotice_base .= '-' . array_shift( $parts );
4878                                 $editnotice_base_msg = wfMessage( $editnotice_base );
4879                                 if ( $editnotice_base_msg->exists() ) {
4880                                         $notices[$editnotice_base] = $editnotice_base_msg->parseAsBlock();
4881                                 }
4882                         }
4883                 } else {
4884                         # Even if there are no subpages in namespace, we still don't want / in MW ns.
4885                         $editnoticeText = $editnotice_ns . '-' . str_replace( '/', '-', $this->getDBkey() );
4886                         $editnoticeMsg = wfMessage( $editnoticeText );
4887                         if ( $editnoticeMsg->exists() ) {
4888                                 $notices[$editnoticeText] = $editnoticeMsg->parseAsBlock();
4889                         }
4890                 }
4891
4892                 wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4893                 return $notices;
4894         }
4895 }