includes/Title.php

   1 <?php
   2 /**
   3  * Representation of 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  * @note Consider using a TitleValue object instead. TitleValue is more lightweight
  31  *       and does not rely on global state or the database.
  32  */
  33 class Title {
  34         /** @var HashBagOStuff */
  35         static private $titleCache = null;
  36
  37         /**
  38          * Title::newFromText maintains a cache to avoid expensive re-normalization of
  39          * commonly used titles. On a batch operation this can become a memory leak
  40          * if not bounded. After hitting this many titles reset the cache.
  41          */
  42         const CACHE_MAX = 1000;
  43
  44         /**
  45          * Used to be GAID_FOR_UPDATE define. Used with getArticleID() and friends
  46          * to use the master DB
  47          */
  48         const GAID_FOR_UPDATE = 1;
  49
  50         /**
  51          * @name Private member variables
  52          * Please use the accessor functions instead.
  53          * @private
  54          */
  55         // @{
  56
  57         /** @var string Text form (spaces not underscores) of the main part */
  58         public $mTextform = '';
  59
  60         /** @var string URL-encoded form of the main part */
  61         public $mUrlform = '';
  62
  63         /** @var string Main part with underscores */
  64         public $mDbkeyform = '';
  65
  66         /** @var string Database key with the initial letter in the case specified by the user */
  67         protected $mUserCaseDBKey;
  68
  69         /** @var int Namespace index, i.e. one of the NS_xxxx constants */
  70         public $mNamespace = NS_MAIN;
  71
  72         /** @var string Interwiki prefix */
  73         public $mInterwiki = '';
  74
  75         /** @var bool Was this Title created from a string with a local interwiki prefix? */
  76         private $mLocalInterwiki = false;
  77
  78         /** @var string Title fragment (i.e. the bit after the #) */
  79         public $mFragment = '';
  80
  81         /** @var int Article ID, fetched from the link cache on demand */
  82         public $mArticleID = -1;
  83
  84         /** @var bool|int ID of most recent revision */
  85         protected $mLatestID = false;
  86
  87         /**
  88          * @var bool|string ID of the page's content model, i.e. one of the
  89          *   CONTENT_MODEL_XXX constants
  90          */
  91         public $mContentModel = false;
  92
  93         /** @var int Estimated number of revisions; null of not loaded */
  94         private $mEstimateRevisions;
  95
  96         /** @var array Array of groups allowed to edit this article */
  97         public $mRestrictions = array();
  98
  99         /** @var string|bool */
 100         protected $mOldRestrictions = false;
 101
 102         /** @var bool Cascade restrictions on this page to included templates and images? */
 103         public $mCascadeRestriction;
 104
 105         /** Caching the results of getCascadeProtectionSources */
 106         public $mCascadingRestrictions;
 107
 108         /** @var array When do the restrictions on this page expire? */
 109         protected $mRestrictionsExpiry = array();
 110
 111         /** @var bool Are cascading restrictions in effect on this page? */
 112         protected $mHasCascadingRestrictions;
 113
 114         /** @var array Where are the cascading restrictions coming from on this page? */
 115         public $mCascadeSources;
 116
 117         /** @var bool Boolean for initialisation on demand */
 118         public $mRestrictionsLoaded = false;
 119
 120         /** @var string Text form including namespace/interwiki, initialised on demand */
 121         protected $mPrefixedText = null;
 122
 123         /** @var mixed Cached value for getTitleProtection (create protection) */
 124         public $mTitleProtection;
 125
 126         /**
 127          * @var int Namespace index when there is no namespace. Don't change the
 128          *   following default, NS_MAIN is hardcoded in several places. See bug 696.
 129          *   Zero except in {{transclusion}} tags.
 130          */
 131         public $mDefaultNamespace = NS_MAIN;
 132
 133         /**
 134          * @var bool Is $wgUser watching this page? null if unfilled, accessed
 135          * through userIsWatching()
 136          */
 137         protected $mWatched = null;
 138
 139         /** @var int The page length, 0 for special pages */
 140         protected $mLength = -1;
 141
 142         /** @var null Is the article at this title a redirect? */
 143         public $mRedirect = null;
 144
 145         /** @var array Associative array of user ID -> timestamp/false */
 146         private $mNotificationTimestamp = array();
 147
 148         /** @var bool Whether a page has any subpages */
 149         private $mHasSubpages;
 150
 151         /** @var bool The (string) language code of the page's language and content code. */
 152         private $mPageLanguage = false;
 153
 154         /** @var string The page language code from the database */
 155         private $mDbPageLanguage = null;
 156
 157         /** @var TitleValue A corresponding TitleValue object */
 158         private $mTitleValue = null;
 159
 160         /** @var bool Would deleting this page be a big deletion? */
 161         private $mIsBigDeletion = null;
 162         // @}
 163
 164         /**
 165          * B/C kludge: provide a TitleParser for use by Title.
 166          * Ideally, Title would have no methods that need this.
 167          * Avoid usage of this singleton by using TitleValue
 168          * and the associated services when possible.
 169          *
 170          * @return TitleParser
 171          */
 172         private static function getTitleParser() {
 173                 global $wgContLang, $wgLocalInterwikis;
 174
 175                 static $titleCodec = null;
 176                 static $titleCodecFingerprint = null;
 177
 178                 // $wgContLang and $wgLocalInterwikis may change (especially while testing),
 179                 // make sure we are using the right one. To detect changes over the course
 180                 // of a request, we remember a fingerprint of the config used to create the
 181                 // codec singleton, and re-create it if the fingerprint doesn't match.
 182                 $fingerprint = spl_object_hash( $wgContLang ) . '|' . join( '+', $wgLocalInterwikis );
 183
 184                 if ( $fingerprint !== $titleCodecFingerprint ) {
 185                         $titleCodec = null;
 186                 }
 187
 188                 if ( !$titleCodec ) {
 189                         $titleCodec = new MediaWikiTitleCodec(
 190                                 $wgContLang,
 191                                 GenderCache::singleton(),
 192                                 $wgLocalInterwikis
 193                         );
 194                         $titleCodecFingerprint = $fingerprint;
 195                 }
 196
 197                 return $titleCodec;
 198         }
 199
 200         /**
 201          * B/C kludge: provide a TitleParser for use by Title.
 202          * Ideally, Title would have no methods that need this.
 203          * Avoid usage of this singleton by using TitleValue
 204          * and the associated services when possible.
 205          *
 206          * @return TitleFormatter
 207          */
 208         private static function getTitleFormatter() {
 209                 // NOTE: we know that getTitleParser() returns a MediaWikiTitleCodec,
 210                 //      which implements TitleFormatter.
 211                 return self::getTitleParser();
 212         }
 213
 214         function __construct() {
 215         }
 216
 217         /**
 218          * Create a new Title from a prefixed DB key
 219          *
 220          * @param string $key The database key, which has underscores
 221          *      instead of spaces, possibly including namespace and
 222          *      interwiki prefixes
 223          * @return Title|null Title, or null on an error
 224          */
 225         public static function newFromDBkey( $key ) {
 226                 $t = new Title();
 227                 $t->mDbkeyform = $key;
 228
 229                 try {
 230                         $t->secureAndSplit();
 231                         return $t;
 232                 } catch ( MalformedTitleException $ex ) {
 233                         return null;
 234                 }
 235         }
 236
 237         /**
 238          * Create a new Title from a TitleValue
 239          *
 240          * @param TitleValue $titleValue Assumed to be safe.
 241          *
 242          * @return Title
 243          */
 244         public static function newFromTitleValue( TitleValue $titleValue ) {
 245                 return self::makeTitle(
 246                         $titleValue->getNamespace(),
 247                         $titleValue->getText(),
 248                         $titleValue->getFragment() );
 249         }
 250
 251         /**
 252          * Create a new Title from text, such as what one would find in a link. De-
 253          * codes any HTML entities in the text.
 254          *
 255          * @param string|null $text The link text; spaces, prefixes, and an
 256          *   initial ':' indicating the main namespace are accepted.
 257          * @param int $defaultNamespace The namespace to use if none is specified
 258          *   by a prefix.  If you want to force a specific namespace even if
 259          *   $text might begin with a namespace prefix, use makeTitle() or
 260          *   makeTitleSafe().
 261          * @throws InvalidArgumentException
 262          * @return Title|null Title or null on an error.
 263          */
 264         public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
 265                 if ( is_object( $text ) ) {
 266                         throw new InvalidArgumentException( '$text must be a string.' );
 267                 }
 268                 if ( $text !== null && !is_string( $text ) ) {
 269                         wfDebugLog( 'T76305', wfGetAllCallers( 5 ) );
 270                         return null;
 271                 }
 272                 if ( $text === null ) {
 273                         return null;
 274                 }
 275
 276                 try {
 277                         return Title::newFromTextThrow( $text, $defaultNamespace );
 278                 } catch ( MalformedTitleException $ex ) {
 279                         return null;
 280                 }
 281         }
 282
 283         /**
 284          * Like Title::newFromText(), but throws MalformedTitleException when the title is invalid,
 285          * rather than returning null.
 286          *
 287          * The exception subclasses encode detailed information about why the title is invalid.
 288          *
 289          * @see Title::newFromText
 290          *
 291          * @since 1.25
 292          * @param string $text Title text to check
 293          * @param int $defaultNamespace
 294          * @throws MalformedTitleException If the title is invalid
 295          * @return Title
 296          */
 297         public static function newFromTextThrow( $text, $defaultNamespace = NS_MAIN ) {
 298                 if ( is_object( $text ) ) {
 299                         throw new MWException( '$text must be a string, given an object' );
 300                 }
 301
 302                 $titleCache = self::getTitleCache();
 303
 304                 // Wiki pages often contain multiple links to the same page.
 305                 // Title normalization and parsing can become expensive on pages with many
 306                 // links, so we can save a little time by caching them.
 307                 // In theory these are value objects and won't get changed...
 308                 if ( $defaultNamespace == NS_MAIN ) {
 309                         $t = $titleCache->get( $text );
 310                         if ( $t ) {
 311                                 return $t;
 312                         }
 313                 }
 314
 315                 // Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
 316                 $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );
 317
 318                 $t = new Title();
 319                 $t->mDbkeyform = strtr( $filteredText, ' ', '_' );
 320                 $t->mDefaultNamespace = intval( $defaultNamespace );
 321
 322                 $t->secureAndSplit();
 323                 if ( $defaultNamespace == NS_MAIN ) {
 324                         $titleCache->set( $text, $t );
 325                 }
 326                 return $t;
 327         }
 328
 329         /**
 330          * THIS IS NOT THE FUNCTION YOU WANT. Use Title::newFromText().
 331          *
 332          * Example of wrong and broken code:
 333          * $title = Title::newFromURL( $wgRequest->getVal( 'title' ) );
 334          *
 335          * Example of right code:
 336          * $title = Title::newFromText( $wgRequest->getVal( 'title' ) );
 337          *
 338          * Create a new Title from URL-encoded text. Ensures that
 339          * the given title's length does not exceed the maximum.
 340          *
 341          * @param string $url The title, as might be taken from a URL
 342          * @return Title|null The new object, or null on an error
 343          */
 344         public static function newFromURL( $url ) {
 345                 $t = new Title();
 346
 347                 # For compatibility with old buggy URLs. "+" is usually not valid in titles,
 348                 # but some URLs used it as a space replacement and they still come
 349                 # from some external search tools.
 350                 if ( strpos( self::legalChars(), '+' ) === false ) {
 351                         $url = strtr( $url, '+', ' ' );
 352                 }
 353
 354                 $t->mDbkeyform = strtr( $url, ' ', '_' );
 355
 356                 try {
 357                         $t->secureAndSplit();
 358                         return $t;
 359                 } catch ( MalformedTitleException $ex ) {
 360                         return null;
 361                 }
 362         }
 363
 364         /**
 365          * @return HashBagOStuff
 366          */
 367         private static function getTitleCache() {
 368                 if ( self::$titleCache == null ) {
 369                         self::$titleCache = new HashBagOStuff( array( 'maxKeys' => self::CACHE_MAX ) );
 370                 }
 371                 return self::$titleCache;
 372         }
 373
 374         /**
 375          * Returns a list of fields that are to be selected for initializing Title
 376          * objects or LinkCache entries. Uses $wgContentHandlerUseDB to determine
 377          * whether to include page_content_model.
 378          *
 379          * @return array
 380          */
 381         protected static function getSelectFields() {
 382                 global $wgContentHandlerUseDB;
 383
 384                 $fields = array(
 385                         'page_namespace', 'page_title', 'page_id',
 386                         'page_len', 'page_is_redirect', 'page_latest',
 387                 );
 388
 389                 if ( $wgContentHandlerUseDB ) {
 390                         $fields[] = 'page_content_model';
 391                 }
 392
 393                 return $fields;
 394         }
 395
 396         /**
 397          * Create a new Title from an article ID
 398          *
 399          * @param int $id The page_id corresponding to the Title to create
 400          * @param int $flags Use Title::GAID_FOR_UPDATE to use master
 401          * @return Title|null The new object, or null on an error
 402          */
 403         public static function newFromID( $id, $flags = 0 ) {
 404                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
 405                 $row = $db->selectRow(
 406                         'page',
 407                         self::getSelectFields(),
 408                         array( 'page_id' => $id ),
 409                         __METHOD__
 410                 );
 411                 if ( $row !== false ) {
 412                         $title = Title::newFromRow( $row );
 413                 } else {
 414                         $title = null;
 415                 }
 416                 return $title;
 417         }
 418
 419         /**
 420          * Make an array of titles from an array of IDs
 421          *
 422          * @param int[] $ids Array of IDs
 423          * @return Title[] Array of Titles
 424          */
 425         public static function newFromIDs( $ids ) {
 426                 if ( !count( $ids ) ) {
 427                         return array();
 428                 }
 429                 $dbr = wfGetDB( DB_SLAVE );
 430
 431                 $res = $dbr->select(
 432                         'page',
 433                         self::getSelectFields(),
 434                         array( 'page_id' => $ids ),
 435                         __METHOD__
 436                 );
 437
 438                 $titles = array();
 439                 foreach ( $res as $row ) {
 440                         $titles[] = Title::newFromRow( $row );
 441                 }
 442                 return $titles;
 443         }
 444
 445         /**
 446          * Make a Title object from a DB row
 447          *
 448          * @param stdClass $row Object database row (needs at least page_title,page_namespace)
 449          * @return Title Corresponding Title
 450          */
 451         public static function newFromRow( $row ) {
 452                 $t = self::makeTitle( $row->page_namespace, $row->page_title );
 453                 $t->loadFromRow( $row );
 454                 return $t;
 455         }
 456
 457         /**
 458          * Load Title object fields from a DB row.
 459          * If false is given, the title will be treated as non-existing.
 460          *
 461          * @param stdClass|bool $row Database row
 462          */
 463         public function loadFromRow( $row ) {
 464                 if ( $row ) { // page found
 465                         if ( isset( $row->page_id ) ) {
 466                                 $this->mArticleID = (int)$row->page_id;
 467                         }
 468                         if ( isset( $row->page_len ) ) {
 469                                 $this->mLength = (int)$row->page_len;
 470                         }
 471                         if ( isset( $row->page_is_redirect ) ) {
 472                                 $this->mRedirect = (bool)$row->page_is_redirect;
 473                         }
 474                         if ( isset( $row->page_latest ) ) {
 475                                 $this->mLatestID = (int)$row->page_latest;
 476                         }
 477                         if ( isset( $row->page_content_model ) ) {
 478                                 $this->mContentModel = strval( $row->page_content_model );
 479                         } else {
 480                                 $this->mContentModel = false; # initialized lazily in getContentModel()
 481                         }
 482                         if ( isset( $row->page_lang ) ) {
 483                                 $this->mDbPageLanguage = (string)$row->page_lang;
 484                         }
 485                         if ( isset( $row->page_restrictions ) ) {
 486                                 $this->mOldRestrictions = $row->page_restrictions;
 487                         }
 488                 } else { // page not found
 489                         $this->mArticleID = 0;
 490                         $this->mLength = 0;
 491                         $this->mRedirect = false;
 492                         $this->mLatestID = 0;
 493                         $this->mContentModel = false; # initialized lazily in getContentModel()
 494                 }
 495         }
 496
 497         /**
 498          * Create a new Title from a namespace index and a DB key.
 499          * It's assumed that $ns and $title are *valid*, for instance when
 500          * they came directly from the database or a special page name.
 501          * For convenience, spaces are converted to underscores so that
 502          * eg user_text fields can be used directly.
 503          *
 504          * @param int $ns The namespace of the article
 505          * @param string $title The unprefixed database key form
 506          * @param string $fragment The link fragment (after the "#")
 507          * @param string $interwiki The interwiki prefix
 508          * @return Title The new object
 509          */
 510         public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
 511                 $t = new Title();
 512                 $t->mInterwiki = $interwiki;
 513                 $t->mFragment = $fragment;
 514                 $t->mNamespace = $ns = intval( $ns );
 515                 $t->mDbkeyform = strtr( $title, ' ', '_' );
 516                 $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
 517                 $t->mUrlform = wfUrlencode( $t->mDbkeyform );
 518                 $t->mTextform = strtr( $title, '_', ' ' );
 519                 $t->mContentModel = false; # initialized lazily in getContentModel()
 520                 return $t;
 521         }
 522
 523         /**
 524          * Create a new Title from a namespace index and a DB key.
 525          * The parameters will be checked for validity, which is a bit slower
 526          * than makeTitle() but safer for user-provided data.
 527          *
 528          * @param int $ns The namespace of the article
 529          * @param string $title Database key form
 530          * @param string $fragment The link fragment (after the "#")
 531          * @param string $interwiki Interwiki prefix
 532          * @return Title|null The new object, or null on an error
 533          */
 534         public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
 535                 if ( !MWNamespace::exists( $ns ) ) {
 536                         return null;
 537                 }
 538
 539                 $t = new Title();
 540                 $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki, true );
 541
 542                 try {
 543                         $t->secureAndSplit();
 544                         return $t;
 545                 } catch ( MalformedTitleException $ex ) {
 546                         return null;
 547                 }
 548         }
 549
 550         /**
 551          * Create a new Title for the Main Page
 552          *
 553          * @return Title The new object
 554          */
 555         public static function newMainPage() {
 556                 $title = Title::newFromText( wfMessage( 'mainpage' )->inContentLanguage()->text() );
 557                 // Don't give fatal errors if the message is broken
 558                 if ( !$title ) {
 559                         $title = Title::newFromText( 'Main Page' );
 560                 }
 561                 return $title;
 562         }
 563
 564         /**
 565          * Extract a redirect destination from a string and return the
 566          * Title, or null if the text doesn't contain a valid redirect
 567          * This will only return the very next target, useful for
 568          * the redirect table and other checks that don't need full recursion
 569          *
 570          * @param string $text Text with possible redirect
 571          * @return Title The corresponding Title
 572          * @deprecated since 1.21, use Content::getRedirectTarget instead.
 573          */
 574         public static function newFromRedirect( $text ) {
 575                 ContentHandler::deprecated( __METHOD__, '1.21' );
 576
 577                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 578                 return $content->getRedirectTarget();
 579         }
 580
 581         /**
 582          * Extract a redirect destination from a string and return the
 583          * Title, or null if the text doesn't contain a valid redirect
 584          * This will recurse down $wgMaxRedirects times or until a non-redirect target is hit
 585          * in order to provide (hopefully) the Title of the final destination instead of another redirect
 586          *
 587          * @param string $text Text with possible redirect
 588          * @return Title
 589          * @deprecated since 1.21, use Content::getUltimateRedirectTarget instead.
 590          */
 591         public static function newFromRedirectRecurse( $text ) {
 592                 ContentHandler::deprecated( __METHOD__, '1.21' );
 593
 594                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 595                 return $content->getUltimateRedirectTarget();
 596         }
 597
 598         /**
 599          * Extract a redirect destination from a string and return an
 600          * array of Titles, or null if the text doesn't contain a valid redirect
 601          * The last element in the array is the final destination after all redirects
 602          * have been resolved (up to $wgMaxRedirects times)
 603          *
 604          * @param string $text Text with possible redirect
 605          * @return Title[] Array of Titles, with the destination last
 606          * @deprecated since 1.21, use Content::getRedirectChain instead.
 607          */
 608         public static function newFromRedirectArray( $text ) {
 609                 ContentHandler::deprecated( __METHOD__, '1.21' );
 610
 611                 $content = ContentHandler::makeContent( $text, null, CONTENT_MODEL_WIKITEXT );
 612                 return $content->getRedirectChain();
 613         }
 614
 615         /**
 616          * Get the prefixed DB key associated with an ID
 617          *
 618          * @param int $id The page_id of the article
 619          * @return Title|null An object representing the article, or null if no such article was found
 620          */
 621         public static function nameOf( $id ) {
 622                 $dbr = wfGetDB( DB_SLAVE );
 623
 624                 $s = $dbr->selectRow(
 625                         'page',
 626                         array( 'page_namespace', 'page_title' ),
 627                         array( 'page_id' => $id ),
 628                         __METHOD__
 629                 );
 630                 if ( $s === false ) {
 631                         return null;
 632                 }
 633
 634                 $n = self::makeName( $s->page_namespace, $s->page_title );
 635                 return $n;
 636         }
 637
 638         /**
 639          * Get a regex character class describing the legal characters in a link
 640          *
 641          * @return string The list of characters, not delimited
 642          */
 643         public static function legalChars() {
 644                 global $wgLegalTitleChars;
 645                 return $wgLegalTitleChars;
 646         }
 647
 648         /**
 649          * Returns a simple regex that will match on characters and sequences invalid in titles.
 650          * Note that this doesn't pick up many things that could be wrong with titles, but that
 651          * replacing this regex with something valid will make many titles valid.
 652          *
 653          * @deprecated since 1.25, use MediaWikiTitleCodec::getTitleInvalidRegex() instead
 654          *
 655          * @return string Regex string
 656          */
 657         static function getTitleInvalidRegex() {
 658                 wfDeprecated( __METHOD__, '1.25' );
 659                 return MediaWikiTitleCodec::getTitleInvalidRegex();
 660         }
 661
 662         /**
 663          * Utility method for converting a character sequence from bytes to Unicode.
 664          *
 665          * Primary usecase being converting $wgLegalTitleChars to a sequence usable in
 666          * javascript, as PHP uses UTF-8 bytes where javascript uses Unicode code units.
 667          *
 668          * @param string $byteClass
 669          * @return string
 670          */
 671         public static function convertByteClassToUnicodeClass( $byteClass ) {
 672                 $length = strlen( $byteClass );
 673                 // Input token queue
 674                 $x0 = $x1 = $x2 = '';
 675                 // Decoded queue
 676                 $d0 = $d1 = $d2 = '';
 677                 // Decoded integer codepoints
 678                 $ord0 = $ord1 = $ord2 = 0;
 679                 // Re-encoded queue
 680                 $r0 = $r1 = $r2 = '';
 681                 // Output
 682                 $out = '';
 683                 // Flags
 684                 $allowUnicode = false;
 685                 for ( $pos = 0; $pos < $length; $pos++ ) {
 686                         // Shift the queues down
 687                         $x2 = $x1;
 688                         $x1 = $x0;
 689                         $d2 = $d1;
 690                         $d1 = $d0;
 691                         $ord2 = $ord1;
 692                         $ord1 = $ord0;
 693                         $r2 = $r1;
 694                         $r1 = $r0;
 695                         // Load the current input token and decoded values
 696                         $inChar = $byteClass[$pos];
 697                         if ( $inChar == '\\' ) {
 698                                 if ( preg_match( '/x([0-9a-fA-F]{2})/A', $byteClass, $m, 0, $pos + 1 ) ) {
 699                                         $x0 = $inChar . $m[0];
 700                                         $d0 = chr( hexdec( $m[1] ) );
 701                                         $pos += strlen( $m[0] );
 702                                 } elseif ( preg_match( '/[0-7]{3}/A', $byteClass, $m, 0, $pos + 1 ) ) {
 703                                         $x0 = $inChar . $m[0];
 704                                         $d0 = chr( octdec( $m[0] ) );
 705                                         $pos += strlen( $m[0] );
 706                                 } elseif ( $pos + 1 >= $length ) {
 707                                         $x0 = $d0 = '\\';
 708                                 } else {
 709                                         $d0 = $byteClass[$pos + 1];
 710                                         $x0 = $inChar . $d0;
 711                                         $pos += 1;
 712                                 }
 713                         } else {
 714                                 $x0 = $d0 = $inChar;
 715                         }
 716                         $ord0 = ord( $d0 );
 717                         // Load the current re-encoded value
 718                         if ( $ord0 < 32 || $ord0 == 0x7f ) {
 719                                 $r0 = sprintf( '\x%02x', $ord0 );
 720                         } elseif ( $ord0 >= 0x80 ) {
 721                                 // Allow unicode if a single high-bit character appears
 722                                 $r0 = sprintf( '\x%02x', $ord0 );
 723                                 $allowUnicode = true;
 724                         } elseif ( strpos( '-\\[]^', $d0 ) !== false ) {
 725                                 $r0 = '\\' . $d0;
 726                         } else {
 727                                 $r0 = $d0;
 728                         }
 729                         // Do the output
 730                         if ( $x0 !== '' && $x1 === '-' && $x2 !== '' ) {
 731                                 // Range
 732                                 if ( $ord2 > $ord0 ) {
 733                                         // Empty range
 734                                 } elseif ( $ord0 >= 0x80 ) {
 735                                         // Unicode range
 736                                         $allowUnicode = true;
 737                                         if ( $ord2 < 0x80 ) {
 738                                                 // Keep the non-unicode section of the range
 739                                                 $out .= "$r2-\\x7F";
 740                                         }
 741                                 } else {
 742                                         // Normal range
 743                                         $out .= "$r2-$r0";
 744                                 }
 745                                 // Reset state to the initial value
 746                                 $x0 = $x1 = $d0 = $d1 = $r0 = $r1 = '';
 747                         } elseif ( $ord2 < 0x80 ) {
 748                                 // ASCII character
 749                                 $out .= $r2;
 750                         }
 751                 }
 752                 if ( $ord1 < 0x80 ) {
 753                         $out .= $r1;
 754                 }
 755                 if ( $ord0 < 0x80 ) {
 756                         $out .= $r0;
 757                 }
 758                 if ( $allowUnicode ) {
 759                         $out .= '\u0080-\uFFFF';
 760                 }
 761                 return $out;
 762         }
 763
 764         /**
 765          * Make a prefixed DB key from a DB key and a namespace index
 766          *
 767          * @param int $ns Numerical representation of the namespace
 768          * @param string $title The DB key form the title
 769          * @param string $fragment The link fragment (after the "#")
 770          * @param string $interwiki The interwiki prefix
 771          * @param bool $canonicalNamespace If true, use the canonical name for
 772          *   $ns instead of the localized version.
 773          * @return string The prefixed form of the title
 774          */
 775         public static function makeName( $ns, $title, $fragment = '', $interwiki = '',
 776                 $canonicalNamespace = false
 777         ) {
 778                 global $wgContLang;
 779
 780                 if ( $canonicalNamespace ) {
 781                         $namespace = MWNamespace::getCanonicalName( $ns );
 782                 } else {
 783                         $namespace = $wgContLang->getNsText( $ns );
 784                 }
 785                 $name = $namespace == '' ? $title : "$namespace:$title";
 786                 if ( strval( $interwiki ) != '' ) {
 787                         $name = "$interwiki:$name";
 788                 }
 789                 if ( strval( $fragment ) != '' ) {
 790                         $name .= '#' . $fragment;
 791                 }
 792                 return $name;
 793         }
 794
 795         /**
 796          * Escape a text fragment, say from a link, for a URL
 797          *
 798          * @param string $fragment Containing a URL or link fragment (after the "#")
 799          * @return string Escaped string
 800          */
 801         static function escapeFragmentForURL( $fragment ) {
 802                 # Note that we don't urlencode the fragment.  urlencoded Unicode
 803                 # fragments appear not to work in IE (at least up to 7) or in at least
 804                 # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
 805                 # to care if they aren't encoded.
 806                 return Sanitizer::escapeId( $fragment, 'noninitial' );
 807         }
 808
 809         /**
 810          * Callback for usort() to do title sorts by (namespace, title)
 811          *
 812          * @param Title $a
 813          * @param Title $b
 814          *
 815          * @return int Result of string comparison, or namespace comparison
 816          */
 817         public static function compare( $a, $b ) {
 818                 if ( $a->getNamespace() == $b->getNamespace() ) {
 819                         return strcmp( $a->getText(), $b->getText() );
 820                 } else {
 821                         return $a->getNamespace() - $b->getNamespace();
 822                 }
 823         }
 824
 825         /**
 826          * Determine whether the object refers to a page within
 827          * this project (either this wiki or a wiki with a local
 828          * interwiki, see https://www.mediawiki.org/wiki/Manual:Interwiki_table#iw_local )
 829          *
 830          * @return bool True if this is an in-project interwiki link or a wikilink, false otherwise
 831          */
 832         public function isLocal() {
 833                 if ( $this->isExternal() ) {
 834                         $iw = Interwiki::fetch( $this->mInterwiki );
 835                         if ( $iw ) {
 836                                 return $iw->isLocal();
 837                         }
 838                 }
 839                 return true;
 840         }
 841
 842         /**
 843          * Is this Title interwiki?
 844          *
 845          * @return bool
 846          */
 847         public function isExternal() {
 848                 return $this->mInterwiki !== '';
 849         }
 850
 851         /**
 852          * Get the interwiki prefix
 853          *
 854          * Use Title::isExternal to check if a interwiki is set
 855          *
 856          * @return string Interwiki prefix
 857          */
 858         public function getInterwiki() {
 859                 return $this->mInterwiki;
 860         }
 861
 862         /**
 863          * Was this a local interwiki link?
 864          *
 865          * @return bool
 866          */
 867         public function wasLocalInterwiki() {
 868                 return $this->mLocalInterwiki;
 869         }
 870
 871         /**
 872          * Determine whether the object refers to a page within
 873          * this project and is transcludable.
 874          *
 875          * @return bool True if this is transcludable
 876          */
 877         public function isTrans() {
 878                 if ( !$this->isExternal() ) {
 879                         return false;
 880                 }
 881
 882                 return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
 883         }
 884
 885         /**
 886          * Returns the DB name of the distant wiki which owns the object.
 887          *
 888          * @return string The DB name
 889          */
 890         public function getTransWikiID() {
 891                 if ( !$this->isExternal() ) {
 892                         return false;
 893                 }
 894
 895                 return Interwiki::fetch( $this->mInterwiki )->getWikiID();
 896         }
 897
 898         /**
 899          * Get a TitleValue object representing this Title.
 900          *
 901          * @note Not all valid Titles have a corresponding valid TitleValue
 902          * (e.g. TitleValues cannot represent page-local links that have a
 903          * fragment but no title text).
 904          *
 905          * @return TitleValue|null
 906          */
 907         public function getTitleValue() {
 908                 if ( $this->mTitleValue === null ) {
 909                         try {
 910                                 $this->mTitleValue = new TitleValue(
 911                                         $this->getNamespace(),
 912                                         $this->getDBkey(),
 913                                         $this->getFragment() );
 914                         } catch ( InvalidArgumentException $ex ) {
 915                                 wfDebug( __METHOD__ . ': Can\'t create a TitleValue for [[' .
 916                                         $this->getPrefixedText() . ']]: ' . $ex->getMessage() . "\n" );
 917                         }
 918                 }
 919
 920                 return $this->mTitleValue;
 921         }
 922
 923         /**
 924          * Get the text form (spaces not underscores) of the main part
 925          *
 926          * @return string Main part of the title
 927          */
 928         public function getText() {
 929                 return $this->mTextform;
 930         }
 931
 932         /**
 933          * Get the URL-encoded form of the main part
 934          *
 935          * @return string Main part of the title, URL-encoded
 936          */
 937         public function getPartialURL() {
 938                 return $this->mUrlform;
 939         }
 940
 941         /**
 942          * Get the main part with underscores
 943          *
 944          * @return string Main part of the title, with underscores
 945          */
 946         public function getDBkey() {
 947                 return $this->mDbkeyform;
 948         }
 949
 950         /**
 951          * Get the DB key with the initial letter case as specified by the user
 952          *
 953          * @return string DB key
 954          */
 955         function getUserCaseDBKey() {
 956                 if ( !is_null( $this->mUserCaseDBKey ) ) {
 957                         return $this->mUserCaseDBKey;
 958                 } else {
 959                         // If created via makeTitle(), $this->mUserCaseDBKey is not set.
 960                         return $this->mDbkeyform;
 961                 }
 962         }
 963
 964         /**
 965          * Get the namespace index, i.e. one of the NS_xxxx constants.
 966          *
 967          * @return int Namespace index
 968          */
 969         public function getNamespace() {
 970                 return $this->mNamespace;
 971         }
 972
 973         /**
 974          * Get the page's content model id, see the CONTENT_MODEL_XXX constants.
 975          *
 976          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
 977          * @return string Content model id
 978          */
 979         public function getContentModel( $flags = 0 ) {
 980                 if ( !$this->mContentModel && $this->getArticleID( $flags ) ) {
 981                         $linkCache = LinkCache::singleton();
 982                         $linkCache->addLinkObj( $this ); # in case we already had an article ID
 983                         $this->mContentModel = $linkCache->getGoodLinkFieldObj( $this, 'model' );
 984                 }
 985
 986                 if ( !$this->mContentModel ) {
 987                         $this->mContentModel = ContentHandler::getDefaultModelFor( $this );
 988                 }
 989
 990                 return $this->mContentModel;
 991         }
 992
 993         /**
 994          * Convenience method for checking a title's content model name
 995          *
 996          * @param string $id The content model ID (use the CONTENT_MODEL_XXX constants).
 997          * @return bool True if $this->getContentModel() == $id
 998          */
 999         public function hasContentModel( $id ) {
1000                 return $this->getContentModel() == $id;
1001         }
1002
1003         /**
1004          * Get the namespace text
1005          *
1006          * @return string Namespace text
1007          */
1008         public function getNsText() {
1009                 if ( $this->isExternal() ) {
1010                         // This probably shouldn't even happen,
1011                         // but for interwiki transclusion it sometimes does.
1012                         // Use the canonical namespaces if possible to try to
1013                         // resolve a foreign namespace.
1014                         if ( MWNamespace::exists( $this->mNamespace ) ) {
1015                                 return MWNamespace::getCanonicalName( $this->mNamespace );
1016                         }
1017                 }
1018
1019                 try {
1020                         $formatter = self::getTitleFormatter();
1021                         return $formatter->getNamespaceName( $this->mNamespace, $this->mDbkeyform );
1022                 } catch ( InvalidArgumentException $ex ) {
1023                         wfDebug( __METHOD__ . ': ' . $ex->getMessage() . "\n" );
1024                         return false;
1025                 }
1026         }
1027
1028         /**
1029          * Get the namespace text of the subject (rather than talk) page
1030          *
1031          * @return string Namespace text
1032          */
1033         public function getSubjectNsText() {
1034                 global $wgContLang;
1035                 return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
1036         }
1037
1038         /**
1039          * Get the namespace text of the talk page
1040          *
1041          * @return string Namespace text
1042          */
1043         public function getTalkNsText() {
1044                 global $wgContLang;
1045                 return $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) );
1046         }
1047
1048         /**
1049          * Could this title have a corresponding talk page?
1050          *
1051          * @return bool
1052          */
1053         public function canTalk() {
1054                 return MWNamespace::canTalk( $this->mNamespace );
1055         }
1056
1057         /**
1058          * Is this in a namespace that allows actual pages?
1059          *
1060          * @return bool
1061          */
1062         public function canExist() {
1063                 return $this->mNamespace >= NS_MAIN;
1064         }
1065
1066         /**
1067          * Can this title be added to a user's watchlist?
1068          *
1069          * @return bool
1070          */
1071         public function isWatchable() {
1072                 return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
1073         }
1074
1075         /**
1076          * Returns true if this is a special page.
1077          *
1078          * @return bool
1079          */
1080         public function isSpecialPage() {
1081                 return $this->getNamespace() == NS_SPECIAL;
1082         }
1083
1084         /**
1085          * Returns true if this title resolves to the named special page
1086          *
1087          * @param string $name The special page name
1088          * @return bool
1089          */
1090         public function isSpecial( $name ) {
1091                 if ( $this->isSpecialPage() ) {
1092                         list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
1093                         if ( $name == $thisName ) {
1094                                 return true;
1095                         }
1096                 }
1097                 return false;
1098         }
1099
1100         /**
1101          * If the Title refers to a special page alias which is not the local default, resolve
1102          * the alias, and localise the name as necessary.  Otherwise, return $this
1103          *
1104          * @return Title
1105          */
1106         public function fixSpecialName() {
1107                 if ( $this->isSpecialPage() ) {
1108                         list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
1109                         if ( $canonicalName ) {
1110                                 $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
1111                                 if ( $localName != $this->mDbkeyform ) {
1112                                         return Title::makeTitle( NS_SPECIAL, $localName );
1113                                 }
1114                         }
1115                 }
1116                 return $this;
1117         }
1118
1119         /**
1120          * Returns true if the title is inside the specified namespace.
1121          *
1122          * Please make use of this instead of comparing to getNamespace()
1123          * This function is much more resistant to changes we may make
1124          * to namespaces than code that makes direct comparisons.
1125          * @param int $ns The namespace
1126          * @return bool
1127          * @since 1.19
1128          */
1129         public function inNamespace( $ns ) {
1130                 return MWNamespace::equals( $this->getNamespace(), $ns );
1131         }
1132
1133         /**
1134          * Returns true if the title is inside one of the specified namespaces.
1135          *
1136          * @param int $namespaces,... The namespaces to check for
1137          * @return bool
1138          * @since 1.19
1139          */
1140         public function inNamespaces( /* ... */ ) {
1141                 $namespaces = func_get_args();
1142                 if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
1143                         $namespaces = $namespaces[0];
1144                 }
1145
1146                 foreach ( $namespaces as $ns ) {
1147                         if ( $this->inNamespace( $ns ) ) {
1148                                 return true;
1149                         }
1150                 }
1151
1152                 return false;
1153         }
1154
1155         /**
1156          * Returns true if the title has the same subject namespace as the
1157          * namespace specified.
1158          * For example this method will take NS_USER and return true if namespace
1159          * is either NS_USER or NS_USER_TALK since both of them have NS_USER
1160          * as their subject namespace.
1161          *
1162          * This is MUCH simpler than individually testing for equivalence
1163          * against both NS_USER and NS_USER_TALK, and is also forward compatible.
1164          * @since 1.19
1165          * @param int $ns
1166          * @return bool
1167          */
1168         public function hasSubjectNamespace( $ns ) {
1169                 return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
1170         }
1171
1172         /**
1173          * Is this Title in a namespace which contains content?
1174          * In other words, is this a content page, for the purposes of calculating
1175          * statistics, etc?
1176          *
1177          * @return bool
1178          */
1179         public function isContentPage() {
1180                 return MWNamespace::isContent( $this->getNamespace() );
1181         }
1182
1183         /**
1184          * Would anybody with sufficient privileges be able to move this page?
1185          * Some pages just aren't movable.
1186          *
1187          * @return bool
1188          */
1189         public function isMovable() {
1190                 if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->isExternal() ) {
1191                         // Interwiki title or immovable namespace. Hooks don't get to override here
1192                         return false;
1193                 }
1194
1195                 $result = true;
1196                 Hooks::run( 'TitleIsMovable', array( $this, &$result ) );
1197                 return $result;
1198         }
1199
1200         /**
1201          * Is this the mainpage?
1202          * @note Title::newFromText seems to be sufficiently optimized by the title
1203          * cache that we don't need to over-optimize by doing direct comparisons and
1204          * accidentally creating new bugs where $title->equals( Title::newFromText() )
1205          * ends up reporting something differently than $title->isMainPage();
1206          *
1207          * @since 1.18
1208          * @return bool
1209          */
1210         public function isMainPage() {
1211                 return $this->equals( Title::newMainPage() );
1212         }
1213
1214         /**
1215          * Is this a subpage?
1216          *
1217          * @return bool
1218          */
1219         public function isSubpage() {
1220                 return MWNamespace::hasSubpages( $this->mNamespace )
1221                         ? strpos( $this->getText(), '/' ) !== false
1222                         : false;
1223         }
1224
1225         /**
1226          * Is this a conversion table for the LanguageConverter?
1227          *
1228          * @return bool
1229          */
1230         public function isConversionTable() {
1231                 // @todo ConversionTable should become a separate content model.
1232
1233                 return $this->getNamespace() == NS_MEDIAWIKI &&
1234                         strpos( $this->getText(), 'Conversiontable/' ) === 0;
1235         }
1236
1237         /**
1238          * Does that page contain wikitext, or it is JS, CSS or whatever?
1239          *
1240          * @return bool
1241          */
1242         public function isWikitextPage() {
1243                 return $this->hasContentModel( CONTENT_MODEL_WIKITEXT );
1244         }
1245
1246         /**
1247          * Could this page contain custom CSS or JavaScript for the global UI.
1248          * This is generally true for pages in the MediaWiki namespace having CONTENT_MODEL_CSS
1249          * or CONTENT_MODEL_JAVASCRIPT.
1250          *
1251          * This method does *not* return true for per-user JS/CSS. Use isCssJsSubpage()
1252          * for that!
1253          *
1254          * Note that this method should not return true for pages that contain and
1255          * show "inactive" CSS or JS.
1256          *
1257          * @return bool
1258          */
1259         public function isCssOrJsPage() {
1260                 $isCssOrJsPage = NS_MEDIAWIKI == $this->mNamespace
1261                         && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1262                                 || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1263
1264                 # @note This hook is also called in ContentHandler::getDefaultModel.
1265                 #   It's called here again to make sure hook functions can force this
1266                 #   method to return true even outside the MediaWiki namespace.
1267
1268                 Hooks::run( 'TitleIsCssOrJsPage', array( $this, &$isCssOrJsPage ), '1.25' );
1269
1270                 return $isCssOrJsPage;
1271         }
1272
1273         /**
1274          * Is this a .css or .js subpage of a user page?
1275          * @return bool
1276          */
1277         public function isCssJsSubpage() {
1278                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1279                                 && ( $this->hasContentModel( CONTENT_MODEL_CSS )
1280                                         || $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) ) );
1281         }
1282
1283         /**
1284          * Trim down a .css or .js subpage title to get the corresponding skin name
1285          *
1286          * @return string Containing skin name from .css or .js subpage title
1287          */
1288         public function getSkinFromCssJsSubpage() {
1289                 $subpage = explode( '/', $this->mTextform );
1290                 $subpage = $subpage[count( $subpage ) - 1];
1291                 $lastdot = strrpos( $subpage, '.' );
1292                 if ( $lastdot === false ) {
1293                         return $subpage; # Never happens: only called for names ending in '.css' or '.js'
1294                 }
1295                 return substr( $subpage, 0, $lastdot );
1296         }
1297
1298         /**
1299          * Is this a .css subpage of a user page?
1300          *
1301          * @return bool
1302          */
1303         public function isCssSubpage() {
1304                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1305                         && $this->hasContentModel( CONTENT_MODEL_CSS ) );
1306         }
1307
1308         /**
1309          * Is this a .js subpage of a user page?
1310          *
1311          * @return bool
1312          */
1313         public function isJsSubpage() {
1314                 return ( NS_USER == $this->mNamespace && $this->isSubpage()
1315                         && $this->hasContentModel( CONTENT_MODEL_JAVASCRIPT ) );
1316         }
1317
1318         /**
1319          * Is this a talk page of some sort?
1320          *
1321          * @return bool
1322          */
1323         public function isTalkPage() {
1324                 return MWNamespace::isTalk( $this->getNamespace() );
1325         }
1326
1327         /**
1328          * Get a Title object associated with the talk page of this article
1329          *
1330          * @return Title The object for the talk page
1331          */
1332         public function getTalkPage() {
1333                 return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
1334         }
1335
1336         /**
1337          * Get a title object associated with the subject page of this
1338          * talk page
1339          *
1340          * @return Title The object for the subject page
1341          */
1342         public function getSubjectPage() {
1343                 // Is this the same title?
1344                 $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
1345                 if ( $this->getNamespace() == $subjectNS ) {
1346                         return $this;
1347                 }
1348                 return Title::makeTitle( $subjectNS, $this->getDBkey() );
1349         }
1350
1351         /**
1352          * Get the other title for this page, if this is a subject page
1353          * get the talk page, if it is a subject page get the talk page
1354          *
1355          * @since 1.25
1356          * @throws MWException
1357          * @return Title
1358          */
1359         public function getOtherPage() {
1360                 if ( $this->isSpecialPage() ) {
1361                         throw new MWException( 'Special pages cannot have other pages' );
1362                 }
1363                 if ( $this->isTalkPage() ) {
1364                         return $this->getSubjectPage();
1365                 } else {
1366                         return $this->getTalkPage();
1367                 }
1368         }
1369
1370         /**
1371          * Get the default namespace index, for when there is no namespace
1372          *
1373          * @return int Default namespace index
1374          */
1375         public function getDefaultNamespace() {
1376                 return $this->mDefaultNamespace;
1377         }
1378
1379         /**
1380          * Get the Title fragment (i.e.\ the bit after the #) in text form
1381          *
1382          * Use Title::hasFragment to check for a fragment
1383          *
1384          * @return string Title fragment
1385          */
1386         public function getFragment() {
1387                 return $this->mFragment;
1388         }
1389
1390         /**
1391          * Check if a Title fragment is set
1392          *
1393          * @return bool
1394          * @since 1.23
1395          */
1396         public function hasFragment() {
1397                 return $this->mFragment !== '';
1398         }
1399
1400         /**
1401          * Get the fragment in URL form, including the "#" character if there is one
1402          * @return string Fragment in URL form
1403          */
1404         public function getFragmentForURL() {
1405                 if ( !$this->hasFragment() ) {
1406                         return '';
1407                 } else {
1408                         return '#' . Title::escapeFragmentForURL( $this->getFragment() );
1409                 }
1410         }
1411
1412         /**
1413          * Set the fragment for this title. Removes the first character from the
1414          * specified fragment before setting, so it assumes you're passing it with
1415          * an initial "#".
1416          *
1417          * Deprecated for public use, use Title::makeTitle() with fragment parameter.
1418          * Still in active use privately.
1419          *
1420          * @private
1421          * @param string $fragment Text
1422          */
1423         public function setFragment( $fragment ) {
1424                 $this->mFragment = strtr( substr( $fragment, 1 ), '_', ' ' );
1425         }
1426
1427         /**
1428          * Prefix some arbitrary text with the namespace or interwiki prefix
1429          * of this object
1430          *
1431          * @param string $name The text
1432          * @return string The prefixed text
1433          */
1434         private function prefix( $name ) {
1435                 $p = '';
1436                 if ( $this->isExternal() ) {
1437                         $p = $this->mInterwiki . ':';
1438                 }
1439
1440                 if ( 0 != $this->mNamespace ) {
1441                         $p .= $this->getNsText() . ':';
1442                 }
1443                 return $p . $name;
1444         }
1445
1446         /**
1447          * Get the prefixed database key form
1448          *
1449          * @return string The prefixed title, with underscores and
1450          *  any interwiki and namespace prefixes
1451          */
1452         public function getPrefixedDBkey() {
1453                 $s = $this->prefix( $this->mDbkeyform );
1454                 $s = strtr( $s, ' ', '_' );
1455                 return $s;
1456         }
1457
1458         /**
1459          * Get the prefixed title with spaces.
1460          * This is the form usually used for display
1461          *
1462          * @return string The prefixed title, with spaces
1463          */
1464         public function getPrefixedText() {
1465                 if ( $this->mPrefixedText === null ) {
1466                         $s = $this->prefix( $this->mTextform );
1467                         $s = strtr( $s, '_', ' ' );
1468                         $this->mPrefixedText = $s;
1469                 }
1470                 return $this->mPrefixedText;
1471         }
1472
1473         /**
1474          * Return a string representation of this title
1475          *
1476          * @return string Representation of this title
1477          */
1478         public function __toString() {
1479                 return $this->getPrefixedText();
1480         }
1481
1482         /**
1483          * Get the prefixed title with spaces, plus any fragment
1484          * (part beginning with '#')
1485          *
1486          * @return string The prefixed title, with spaces and the fragment, including '#'
1487          */
1488         public function getFullText() {
1489                 $text = $this->getPrefixedText();
1490                 if ( $this->hasFragment() ) {
1491                         $text .= '#' . $this->getFragment();
1492                 }
1493                 return $text;
1494         }
1495
1496         /**
1497          * Get the root page name text without a namespace, i.e. the leftmost part before any slashes
1498          *
1499          * @par Example:
1500          * @code
1501          * Title::newFromText('User:Foo/Bar/Baz')->getRootText();
1502          * # returns: 'Foo'
1503          * @endcode
1504          *
1505          * @return string Root name
1506          * @since 1.20
1507          */
1508         public function getRootText() {
1509                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1510                         return $this->getText();
1511                 }
1512
1513                 return strtok( $this->getText(), '/' );
1514         }
1515
1516         /**
1517          * Get the root page name title, i.e. the leftmost part before any slashes
1518          *
1519          * @par Example:
1520          * @code
1521          * Title::newFromText('User:Foo/Bar/Baz')->getRootTitle();
1522          * # returns: Title{User:Foo}
1523          * @endcode
1524          *
1525          * @return Title Root title
1526          * @since 1.20
1527          */
1528         public function getRootTitle() {
1529                 return Title::makeTitle( $this->getNamespace(), $this->getRootText() );
1530         }
1531
1532         /**
1533          * Get the base page name without a namespace, i.e. the part before the subpage name
1534          *
1535          * @par Example:
1536          * @code
1537          * Title::newFromText('User:Foo/Bar/Baz')->getBaseText();
1538          * # returns: 'Foo/Bar'
1539          * @endcode
1540          *
1541          * @return string Base name
1542          */
1543         public function getBaseText() {
1544                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1545                         return $this->getText();
1546                 }
1547
1548                 $parts = explode( '/', $this->getText() );
1549                 # Don't discard the real title if there's no subpage involved
1550                 if ( count( $parts ) > 1 ) {
1551                         unset( $parts[count( $parts ) - 1] );
1552                 }
1553                 return implode( '/', $parts );
1554         }
1555
1556         /**
1557          * Get the base page name title, i.e. the part before the subpage name
1558          *
1559          * @par Example:
1560          * @code
1561          * Title::newFromText('User:Foo/Bar/Baz')->getBaseTitle();
1562          * # returns: Title{User:Foo/Bar}
1563          * @endcode
1564          *
1565          * @return Title Base title
1566          * @since 1.20
1567          */
1568         public function getBaseTitle() {
1569                 return Title::makeTitle( $this->getNamespace(), $this->getBaseText() );
1570         }
1571
1572         /**
1573          * Get the lowest-level subpage name, i.e. the rightmost part after any slashes
1574          *
1575          * @par Example:
1576          * @code
1577          * Title::newFromText('User:Foo/Bar/Baz')->getSubpageText();
1578          * # returns: "Baz"
1579          * @endcode
1580          *
1581          * @return string Subpage name
1582          */
1583         public function getSubpageText() {
1584                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
1585                         return $this->mTextform;
1586                 }
1587                 $parts = explode( '/', $this->mTextform );
1588                 return $parts[count( $parts ) - 1];
1589         }
1590
1591         /**
1592          * Get the title for a subpage of the current page
1593          *
1594          * @par Example:
1595          * @code
1596          * Title::newFromText('User:Foo/Bar/Baz')->getSubpage("Asdf");
1597          * # returns: Title{User:Foo/Bar/Baz/Asdf}
1598          * @endcode
1599          *
1600          * @param string $text The subpage name to add to the title
1601          * @return Title Subpage title
1602          * @since 1.20
1603          */
1604         public function getSubpage( $text ) {
1605                 return Title::makeTitleSafe( $this->getNamespace(), $this->getText() . '/' . $text );
1606         }
1607
1608         /**
1609          * Get a URL-encoded form of the subpage text
1610          *
1611          * @return string URL-encoded subpage name
1612          */
1613         public function getSubpageUrlForm() {
1614                 $text = $this->getSubpageText();
1615                 $text = wfUrlencode( strtr( $text, ' ', '_' ) );
1616                 return $text;
1617         }
1618
1619         /**
1620          * Get a URL-encoded title (not an actual URL) including interwiki
1621          *
1622          * @return string The URL-encoded form
1623          */
1624         public function getPrefixedURL() {
1625                 $s = $this->prefix( $this->mDbkeyform );
1626                 $s = wfUrlencode( strtr( $s, ' ', '_' ) );
1627                 return $s;
1628         }
1629
1630         /**
1631          * Helper to fix up the get{Canonical,Full,Link,Local,Internal}URL args
1632          * get{Canonical,Full,Link,Local,Internal}URL methods accepted an optional
1633          * second argument named variant. This was deprecated in favor
1634          * of passing an array of option with a "variant" key
1635          * Once $query2 is removed for good, this helper can be dropped
1636          * and the wfArrayToCgi moved to getLocalURL();
1637          *
1638          * @since 1.19 (r105919)
1639          * @param array|string $query
1640          * @param bool $query2
1641          * @return string
1642          */
1643         private static function fixUrlQueryArgs( $query, $query2 = false ) {
1644                 if ( $query2 !== false ) {
1645                         wfDeprecated( "Title::get{Canonical,Full,Link,Local,Internal}URL " .
1646                                 "method called with a second parameter is deprecated. Add your " .
1647                                 "parameter to an array passed as the first parameter.", "1.19" );
1648                 }
1649                 if ( is_array( $query ) ) {
1650                         $query = wfArrayToCgi( $query );
1651                 }
1652                 if ( $query2 ) {
1653                         if ( is_string( $query2 ) ) {
1654                                 // $query2 is a string, we will consider this to be
1655                                 // a deprecated $variant argument and add it to the query
1656                                 $query2 = wfArrayToCgi( array( 'variant' => $query2 ) );
1657                         } else {
1658                                 $query2 = wfArrayToCgi( $query2 );
1659                         }
1660                         // If we have $query content add a & to it first
1661                         if ( $query ) {
1662                                 $query .= '&';
1663                         }
1664                         // Now append the queries together
1665                         $query .= $query2;
1666                 }
1667                 return $query;
1668         }
1669
1670         /**
1671          * Get a real URL referring to this title, with interwiki link and
1672          * fragment
1673          *
1674          * @see self::getLocalURL for the arguments.
1675          * @see wfExpandUrl
1676          * @param array|string $query
1677          * @param bool $query2
1678          * @param string $proto Protocol type to use in URL
1679          * @return string The URL
1680          */
1681         public function getFullURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1682                 $query = self::fixUrlQueryArgs( $query, $query2 );
1683
1684                 # Hand off all the decisions on urls to getLocalURL
1685                 $url = $this->getLocalURL( $query );
1686
1687                 # Expand the url to make it a full url. Note that getLocalURL has the
1688                 # potential to output full urls for a variety of reasons, so we use
1689                 # wfExpandUrl instead of simply prepending $wgServer
1690                 $url = wfExpandUrl( $url, $proto );
1691
1692                 # Finally, add the fragment.
1693                 $url .= $this->getFragmentForURL();
1694
1695                 Hooks::run( 'GetFullURL', array( &$this, &$url, $query ) );
1696                 return $url;
1697         }
1698
1699         /**
1700          * Get a URL with no fragment or server name (relative URL) from a Title object.
1701          * If this page is generated with action=render, however,
1702          * $wgServer is prepended to make an absolute URL.
1703          *
1704          * @see self::getFullURL to always get an absolute URL.
1705          * @see self::getLinkURL to always get a URL that's the simplest URL that will be
1706          *  valid to link, locally, to the current Title.
1707          * @see self::newFromText to produce a Title object.
1708          *
1709          * @param string|array $query An optional query string,
1710          *   not used for interwiki links. Can be specified as an associative array as well,
1711          *   e.g., array( 'action' => 'edit' ) (keys and values will be URL-escaped).
1712          *   Some query patterns will trigger various shorturl path replacements.
1713          * @param array $query2 An optional secondary query array. This one MUST
1714          *   be an array. If a string is passed it will be interpreted as a deprecated
1715          *   variant argument and urlencoded into a variant= argument.
1716          *   This second query argument will be added to the $query
1717          *   The second parameter is deprecated since 1.19. Pass it as a key,value
1718          *   pair in the first parameter array instead.
1719          *
1720          * @return string String of the URL.
1721          */
1722         public function getLocalURL( $query = '', $query2 = false ) {
1723                 global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
1724
1725                 $query = self::fixUrlQueryArgs( $query, $query2 );
1726
1727                 $interwiki = Interwiki::fetch( $this->mInterwiki );
1728                 if ( $interwiki ) {
1729                         $namespace = $this->getNsText();
1730                         if ( $namespace != '' ) {
1731                                 # Can this actually happen? Interwikis shouldn't be parsed.
1732                                 # Yes! It can in interwiki transclusion. But... it probably shouldn't.
1733                                 $namespace .= ':';
1734                         }
1735                         $url = $interwiki->getURL( $namespace . $this->getDBkey() );
1736                         $url = wfAppendQuery( $url, $query );
1737                 } else {
1738                         $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
1739                         if ( $query == '' ) {
1740                                 $url = str_replace( '$1', $dbkey, $wgArticlePath );
1741                                 Hooks::run( 'GetLocalURL::Article', array( &$this, &$url ) );
1742                         } else {
1743                                 global $wgVariantArticlePath, $wgActionPaths, $wgContLang;
1744                                 $url = false;
1745                                 $matches = array();
1746
1747                                 if ( !empty( $wgActionPaths )
1748                                         && preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches )
1749                                 ) {
1750                                         $action = urldecode( $matches[2] );
1751                                         if ( isset( $wgActionPaths[$action] ) ) {
1752                                                 $query = $matches[1];
1753                                                 if ( isset( $matches[4] ) ) {
1754                                                         $query .= $matches[4];
1755                                                 }
1756                                                 $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
1757                                                 if ( $query != '' ) {
1758                                                         $url = wfAppendQuery( $url, $query );
1759                                                 }
1760                                         }
1761                                 }
1762
1763                                 if ( $url === false
1764                                         && $wgVariantArticlePath
1765                                         && $wgContLang->getCode() === $this->getPageLanguage()->getCode()
1766                                         && $this->getPageLanguage()->hasVariants()
1767                                         && preg_match( '/^variant=([^&]*)$/', $query, $matches )
1768                                 ) {
1769                                         $variant = urldecode( $matches[1] );
1770                                         if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
1771                                                 // Only do the variant replacement if the given variant is a valid
1772                                                 // variant for the page's language.
1773                                                 $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
1774                                                 $url = str_replace( '$1', $dbkey, $url );
1775                                         }
1776                                 }
1777
1778                                 if ( $url === false ) {
1779                                         if ( $query == '-' ) {
1780                                                 $query = '';
1781                                         }
1782                                         $url = "{$wgScript}?title={$dbkey}&{$query}";
1783                                 }
1784                         }
1785
1786                         Hooks::run( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );
1787
1788                         // @todo FIXME: This causes breakage in various places when we
1789                         // actually expected a local URL and end up with dupe prefixes.
1790                         if ( $wgRequest->getVal( 'action' ) == 'render' ) {
1791                                 $url = $wgServer . $url;
1792                         }
1793                 }
1794                 Hooks::run( 'GetLocalURL', array( &$this, &$url, $query ) );
1795                 return $url;
1796         }
1797
1798         /**
1799          * Get a URL that's the simplest URL that will be valid to link, locally,
1800          * to the current Title.  It includes the fragment, but does not include
1801          * the server unless action=render is used (or the link is external).  If
1802          * there's a fragment but the prefixed text is empty, we just return a link
1803          * to the fragment.
1804          *
1805          * The result obviously should not be URL-escaped, but does need to be
1806          * HTML-escaped if it's being output in HTML.
1807          *
1808          * @param array $query
1809          * @param bool $query2
1810          * @param string $proto Protocol to use; setting this will cause a full URL to be used
1811          * @see self::getLocalURL for the arguments.
1812          * @return string The URL
1813          */
1814         public function getLinkURL( $query = '', $query2 = false, $proto = PROTO_RELATIVE ) {
1815                 if ( $this->isExternal() || $proto !== PROTO_RELATIVE ) {
1816                         $ret = $this->getFullURL( $query, $query2, $proto );
1817                 } elseif ( $this->getPrefixedText() === '' && $this->hasFragment() ) {
1818                         $ret = $this->getFragmentForURL();
1819                 } else {
1820                         $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
1821                 }
1822                 return $ret;
1823         }
1824
1825         /**
1826          * Get the URL form for an internal link.
1827          * - Used in various CDN-related code, in case we have a different
1828          * internal hostname for the server from the exposed one.
1829          *
1830          * This uses $wgInternalServer to qualify the path, or $wgServer
1831          * if $wgInternalServer is not set. If the server variable used is
1832          * protocol-relative, the URL will be expanded to http://
1833          *
1834          * @see self::getLocalURL for the arguments.
1835          * @return string The URL
1836          */
1837         public function getInternalURL( $query = '', $query2 = false ) {
1838                 global $wgInternalServer, $wgServer;
1839                 $query = self::fixUrlQueryArgs( $query, $query2 );
1840                 $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
1841                 $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
1842                 Hooks::run( 'GetInternalURL', array( &$this, &$url, $query ) );
1843                 return $url;
1844         }
1845
1846         /**
1847          * Get the URL for a canonical link, for use in things like IRC and
1848          * e-mail notifications. Uses $wgCanonicalServer and the
1849          * GetCanonicalURL hook.
1850          *
1851          * NOTE: Unlike getInternalURL(), the canonical URL includes the fragment
1852          *
1853          * @see self::getLocalURL for the arguments.
1854          * @return string The URL
1855          * @since 1.18
1856          */
1857         public function getCanonicalURL( $query = '', $query2 = false ) {
1858                 $query = self::fixUrlQueryArgs( $query, $query2 );
1859                 $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
1860                 Hooks::run( 'GetCanonicalURL', array( &$this, &$url, $query ) );
1861                 return $url;
1862         }
1863
1864         /**
1865          * Get the edit URL for this Title
1866          *
1867          * @return string The URL, or a null string if this is an interwiki link
1868          */
1869         public function getEditURL() {
1870                 if ( $this->isExternal() ) {
1871                         return '';
1872                 }
1873                 $s = $this->getLocalURL( 'action=edit' );
1874
1875                 return $s;
1876         }
1877
1878         /**
1879          * Is $wgUser watching this page?
1880          *
1881          * @deprecated since 1.20; use User::isWatched() instead.
1882          * @return bool
1883          */
1884         public function userIsWatching() {
1885                 global $wgUser;
1886
1887                 if ( is_null( $this->mWatched ) ) {
1888                         if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
1889                                 $this->mWatched = false;
1890                         } else {
1891                                 $this->mWatched = $wgUser->isWatched( $this );
1892                         }
1893                 }
1894                 return $this->mWatched;
1895         }
1896
1897         /**
1898          * Can $user perform $action on this page?
1899          * This skips potentially expensive cascading permission checks
1900          * as well as avoids expensive error formatting
1901          *
1902          * Suitable for use for nonessential UI controls in common cases, but
1903          * _not_ for functional access control.
1904          *
1905          * May provide false positives, but should never provide a false negative.
1906          *
1907          * @param string $action Action that permission needs to be checked for
1908          * @param User $user User to check (since 1.19); $wgUser will be used if not provided.
1909          * @return bool
1910          */
1911         public function quickUserCan( $action, $user = null ) {
1912                 return $this->userCan( $action, $user, false );
1913         }
1914
1915         /**
1916          * Can $user perform $action on this page?
1917          *
1918          * @param string $action Action that permission needs to be checked for
1919          * @param User $user User to check (since 1.19); $wgUser will be used if not
1920          *   provided.
1921          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1922          * @return bool
1923          */
1924         public function userCan( $action, $user = null, $rigor = 'secure' ) {
1925                 if ( !$user instanceof User ) {
1926                         global $wgUser;
1927                         $user = $wgUser;
1928                 }
1929
1930                 return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $rigor, true ) );
1931         }
1932
1933         /**
1934          * Can $user perform $action on this page?
1935          *
1936          * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
1937          *
1938          * @param string $action Action that permission needs to be checked for
1939          * @param User $user User to check
1940          * @param string $rigor One of (quick,full,secure)
1941          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
1942          *   - full   : does cheap and expensive checks possibly from a slave
1943          *   - secure : does cheap and expensive checks, using the master as needed
1944          * @param array $ignoreErrors Array of Strings Set this to a list of message keys
1945          *   whose corresponding errors may be ignored.
1946          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
1947          */
1948         public function getUserPermissionsErrors(
1949                 $action, $user, $rigor = 'secure', $ignoreErrors = array()
1950         ) {
1951                 $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $rigor );
1952
1953                 // Remove the errors being ignored.
1954                 foreach ( $errors as $index => $error ) {
1955                         $errKey = is_array( $error ) ? $error[0] : $error;
1956
1957                         if ( in_array( $errKey, $ignoreErrors ) ) {
1958                                 unset( $errors[$index] );
1959                         }
1960                         if ( $errKey instanceof MessageSpecifier && in_array( $errKey->getKey(), $ignoreErrors ) ) {
1961                                 unset( $errors[$index] );
1962                         }
1963                 }
1964
1965                 return $errors;
1966         }
1967
1968         /**
1969          * Permissions checks that fail most often, and which are easiest to test.
1970          *
1971          * @param string $action The action to check
1972          * @param User $user User to check
1973          * @param array $errors List of current errors
1974          * @param string $rigor Same format as Title::getUserPermissionsErrors()
1975          * @param bool $short Short circuit on first error
1976          *
1977          * @return array List of errors
1978          */
1979         private function checkQuickPermissions( $action, $user, $errors, $rigor, $short ) {
1980                 if ( !Hooks::run( 'TitleQuickPermissions',
1981                         array( $this, $user, $action, &$errors, ( $rigor !== 'quick' ), $short ) )
1982                 ) {
1983                         return $errors;
1984                 }
1985
1986                 if ( $action == 'create' ) {
1987                         if (
1988                                 ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
1989                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) )
1990                         ) {
1991                                 $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
1992                         }
1993                 } elseif ( $action == 'move' ) {
1994                         if ( !$user->isAllowed( 'move-rootuserpages' )
1995                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
1996                                 // Show user page-specific message only if the user can move other pages
1997                                 $errors[] = array( 'cant-move-user-page' );
1998                         }
1999
2000                         // Check if user is allowed to move files if it's a file
2001                         if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
2002                                 $errors[] = array( 'movenotallowedfile' );
2003                         }
2004
2005                         // Check if user is allowed to move category pages if it's a category page
2006                         if ( $this->mNamespace == NS_CATEGORY && !$user->isAllowed( 'move-categorypages' ) ) {
2007                                 $errors[] = array( 'cant-move-category-page' );
2008                         }
2009
2010                         if ( !$user->isAllowed( 'move' ) ) {
2011                                 // User can't move anything
2012                                 $userCanMove = User::groupHasPermission( 'user', 'move' );
2013                                 $autoconfirmedCanMove = User::groupHasPermission( 'autoconfirmed', 'move' );
2014                                 if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
2015                                         // custom message if logged-in users without any special rights can move
2016                                         $errors[] = array( 'movenologintext' );
2017                                 } else {
2018                                         $errors[] = array( 'movenotallowed' );
2019                                 }
2020                         }
2021                 } elseif ( $action == 'move-target' ) {
2022                         if ( !$user->isAllowed( 'move' ) ) {
2023                                 // User can't move anything
2024                                 $errors[] = array( 'movenotallowed' );
2025                         } elseif ( !$user->isAllowed( 'move-rootuserpages' )
2026                                         && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
2027                                 // Show user page-specific message only if the user can move other pages
2028                                 $errors[] = array( 'cant-move-to-user-page' );
2029                         } elseif ( !$user->isAllowed( 'move-categorypages' )
2030                                         && $this->mNamespace == NS_CATEGORY ) {
2031                                 // Show category page-specific message only if the user can move other pages
2032                                 $errors[] = array( 'cant-move-to-category-page' );
2033                         }
2034                 } elseif ( !$user->isAllowed( $action ) ) {
2035                         $errors[] = $this->missingPermissionError( $action, $short );
2036                 }
2037
2038                 return $errors;
2039         }
2040
2041         /**
2042          * Add the resulting error code to the errors array
2043          *
2044          * @param array $errors List of current errors
2045          * @param array $result Result of errors
2046          *
2047          * @return array List of errors
2048          */
2049         private function resultToError( $errors, $result ) {
2050                 if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
2051                         // A single array representing an error
2052                         $errors[] = $result;
2053                 } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
2054                         // A nested array representing multiple errors
2055                         $errors = array_merge( $errors, $result );
2056                 } elseif ( $result !== '' && is_string( $result ) ) {
2057                         // A string representing a message-id
2058                         $errors[] = array( $result );
2059                 } elseif ( $result instanceof MessageSpecifier ) {
2060                         // A message specifier representing an error
2061                         $errors[] = array( $result );
2062                 } elseif ( $result === false ) {
2063                         // a generic "We don't want them to do that"
2064                         $errors[] = array( 'badaccess-group0' );
2065                 }
2066                 return $errors;
2067         }
2068
2069         /**
2070          * Check various permission hooks
2071          *
2072          * @param string $action The action to check
2073          * @param User $user User to check
2074          * @param array $errors List of current errors
2075          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2076          * @param bool $short Short circuit on first error
2077          *
2078          * @return array List of errors
2079          */
2080         private function checkPermissionHooks( $action, $user, $errors, $rigor, $short ) {
2081                 // Use getUserPermissionsErrors instead
2082                 $result = '';
2083                 if ( !Hooks::run( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
2084                         return $result ? array() : array( array( 'badaccess-group0' ) );
2085                 }
2086                 // Check getUserPermissionsErrors hook
2087                 if ( !Hooks::run( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
2088                         $errors = $this->resultToError( $errors, $result );
2089                 }
2090                 // Check getUserPermissionsErrorsExpensive hook
2091                 if (
2092                         $rigor !== 'quick'
2093                         && !( $short && count( $errors ) > 0 )
2094                         && !Hooks::run( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) )
2095                 ) {
2096                         $errors = $this->resultToError( $errors, $result );
2097                 }
2098
2099                 return $errors;
2100         }
2101
2102         /**
2103          * Check permissions on special pages & namespaces
2104          *
2105          * @param string $action The action to check
2106          * @param User $user User to check
2107          * @param array $errors List of current errors
2108          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2109          * @param bool $short Short circuit on first error
2110          *
2111          * @return array List of errors
2112          */
2113         private function checkSpecialsAndNSPermissions( $action, $user, $errors, $rigor, $short ) {
2114                 # Only 'createaccount' can be performed on special pages,
2115                 # which don't actually exist in the DB.
2116                 if ( NS_SPECIAL == $this->mNamespace && $action !== 'createaccount' ) {
2117                         $errors[] = array( 'ns-specialprotected' );
2118                 }
2119
2120                 # Check $wgNamespaceProtection for restricted namespaces
2121                 if ( $this->isNamespaceProtected( $user ) ) {
2122                         $ns = $this->mNamespace == NS_MAIN ?
2123                                 wfMessage( 'nstab-main' )->text() : $this->getNsText();
2124                         $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
2125                                 array( 'protectedinterface', $action ) : array( 'namespaceprotected', $ns, $action );
2126                 }
2127
2128                 return $errors;
2129         }
2130
2131         /**
2132          * Check CSS/JS sub-page permissions
2133          *
2134          * @param string $action The action to check
2135          * @param User $user User to check
2136          * @param array $errors List of current errors
2137          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2138          * @param bool $short Short circuit on first error
2139          *
2140          * @return array List of errors
2141          */
2142         private function checkCSSandJSPermissions( $action, $user, $errors, $rigor, $short ) {
2143                 # Protect css/js subpages of user pages
2144                 # XXX: this might be better using restrictions
2145                 # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
2146                 if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' ) ) {
2147                         if ( preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
2148                                 if ( $this->isCssSubpage() && !$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
2149                                         $errors[] = array( 'mycustomcssprotected', $action );
2150                                 } elseif ( $this->isJsSubpage() && !$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
2151                                         $errors[] = array( 'mycustomjsprotected', $action );
2152                                 }
2153                         } else {
2154                                 if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
2155                                         $errors[] = array( 'customcssprotected', $action );
2156                                 } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
2157                                         $errors[] = array( 'customjsprotected', $action );
2158                                 }
2159                         }
2160                 }
2161
2162                 return $errors;
2163         }
2164
2165         /**
2166          * Check against page_restrictions table requirements on this
2167          * page. The user must possess all required rights for this
2168          * action.
2169          *
2170          * @param string $action The action to check
2171          * @param User $user User to check
2172          * @param array $errors List of current errors
2173          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2174          * @param bool $short Short circuit on first error
2175          *
2176          * @return array List of errors
2177          */
2178         private function checkPageRestrictions( $action, $user, $errors, $rigor, $short ) {
2179                 foreach ( $this->getRestrictions( $action ) as $right ) {
2180                         // Backwards compatibility, rewrite sysop -> editprotected
2181                         if ( $right == 'sysop' ) {
2182                                 $right = 'editprotected';
2183                         }
2184                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2185                         if ( $right == 'autoconfirmed' ) {
2186                                 $right = 'editsemiprotected';
2187                         }
2188                         if ( $right == '' ) {
2189                                 continue;
2190                         }
2191                         if ( !$user->isAllowed( $right ) ) {
2192                                 $errors[] = array( 'protectedpagetext', $right, $action );
2193                         } elseif ( $this->mCascadeRestriction && !$user->isAllowed( 'protect' ) ) {
2194                                 $errors[] = array( 'protectedpagetext', 'protect', $action );
2195                         }
2196                 }
2197
2198                 return $errors;
2199         }
2200
2201         /**
2202          * Check restrictions on cascading pages.
2203          *
2204          * @param string $action The action to check
2205          * @param User $user User to check
2206          * @param array $errors List of current errors
2207          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2208          * @param bool $short Short circuit on first error
2209          *
2210          * @return array List of errors
2211          */
2212         private function checkCascadingSourcesRestrictions( $action, $user, $errors, $rigor, $short ) {
2213                 if ( $rigor !== 'quick' && !$this->isCssJsSubpage() ) {
2214                         # We /could/ use the protection level on the source page, but it's
2215                         # fairly ugly as we have to establish a precedence hierarchy for pages
2216                         # included by multiple cascade-protected pages. So just restrict
2217                         # it to people with 'protect' permission, as they could remove the
2218                         # protection anyway.
2219                         list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
2220                         # Cascading protection depends on more than this page...
2221                         # Several cascading protected pages may include this page...
2222                         # Check each cascading level
2223                         # This is only for protection restrictions, not for all actions
2224                         if ( isset( $restrictions[$action] ) ) {
2225                                 foreach ( $restrictions[$action] as $right ) {
2226                                         // Backwards compatibility, rewrite sysop -> editprotected
2227                                         if ( $right == 'sysop' ) {
2228                                                 $right = 'editprotected';
2229                                         }
2230                                         // Backwards compatibility, rewrite autoconfirmed -> editsemiprotected
2231                                         if ( $right == 'autoconfirmed' ) {
2232                                                 $right = 'editsemiprotected';
2233                                         }
2234                                         if ( $right != '' && !$user->isAllowedAll( 'protect', $right ) ) {
2235                                                 $pages = '';
2236                                                 foreach ( $cascadingSources as $page ) {
2237                                                         $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
2238                                                 }
2239                                                 $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages, $action );
2240                                         }
2241                                 }
2242                         }
2243                 }
2244
2245                 return $errors;
2246         }
2247
2248         /**
2249          * Check action permissions not already checked in checkQuickPermissions
2250          *
2251          * @param string $action The action to check
2252          * @param User $user User to check
2253          * @param array $errors List of current errors
2254          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2255          * @param bool $short Short circuit on first error
2256          *
2257          * @return array List of errors
2258          */
2259         private function checkActionPermissions( $action, $user, $errors, $rigor, $short ) {
2260                 global $wgDeleteRevisionsLimit, $wgLang;
2261
2262                 if ( $action == 'protect' ) {
2263                         if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $rigor, true ) ) ) {
2264                                 // If they can't edit, they shouldn't protect.
2265                                 $errors[] = array( 'protect-cantedit' );
2266                         }
2267                 } elseif ( $action == 'create' ) {
2268                         $title_protection = $this->getTitleProtection();
2269                         if ( $title_protection ) {
2270                                 if ( $title_protection['permission'] == ''
2271                                         || !$user->isAllowed( $title_protection['permission'] )
2272                                 ) {
2273                                         $errors[] = array(
2274                                                 'titleprotected',
2275                                                 User::whoIs( $title_protection['user'] ),
2276                                                 $title_protection['reason']
2277                                         );
2278                                 }
2279                         }
2280                 } elseif ( $action == 'move' ) {
2281                         // Check for immobile pages
2282                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2283                                 // Specific message for this case
2284                                 $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
2285                         } elseif ( !$this->isMovable() ) {
2286                                 // Less specific message for rarer cases
2287                                 $errors[] = array( 'immobile-source-page' );
2288                         }
2289                 } elseif ( $action == 'move-target' ) {
2290                         if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
2291                                 $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
2292                         } elseif ( !$this->isMovable() ) {
2293                                 $errors[] = array( 'immobile-target-page' );
2294                         }
2295                 } elseif ( $action == 'delete' ) {
2296                         $tempErrors = $this->checkPageRestrictions( 'edit', $user, array(), $rigor, true );
2297                         if ( !$tempErrors ) {
2298                                 $tempErrors = $this->checkCascadingSourcesRestrictions( 'edit',
2299                                         $user, $tempErrors, $rigor, true );
2300                         }
2301                         if ( $tempErrors ) {
2302                                 // If protection keeps them from editing, they shouldn't be able to delete.
2303                                 $errors[] = array( 'deleteprotected' );
2304                         }
2305                         if ( $rigor !== 'quick' && $wgDeleteRevisionsLimit
2306                                 && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion()
2307                         ) {
2308                                 $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
2309                         }
2310                 }
2311                 return $errors;
2312         }
2313
2314         /**
2315          * Check that the user isn't blocked from editing.
2316          *
2317          * @param string $action The action to check
2318          * @param User $user User to check
2319          * @param array $errors List of current errors
2320          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2321          * @param bool $short Short circuit on first error
2322          *
2323          * @return array List of errors
2324          */
2325         private function checkUserBlock( $action, $user, $errors, $rigor, $short ) {
2326                 // Account creation blocks handled at userlogin.
2327                 // Unblocking handled in SpecialUnblock
2328                 if ( $rigor === 'quick' || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
2329                         return $errors;
2330                 }
2331
2332                 global $wgEmailConfirmToEdit;
2333
2334                 if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
2335                         $errors[] = array( 'confirmedittext' );
2336                 }
2337
2338                 $useSlave = ( $rigor !== 'secure' );
2339                 if ( ( $action == 'edit' || $action == 'create' )
2340                         && !$user->isBlockedFrom( $this, $useSlave )
2341                 ) {
2342                         // Don't block the user from editing their own talk page unless they've been
2343                         // explicitly blocked from that too.
2344                 } elseif ( $user->isBlocked() && $user->getBlock()->prevents( $action ) !== false ) {
2345                         // @todo FIXME: Pass the relevant context into this function.
2346                         $errors[] = $user->getBlock()->getPermissionsError( RequestContext::getMain() );
2347                 }
2348
2349                 return $errors;
2350         }
2351
2352         /**
2353          * Check that the user is allowed to read this page.
2354          *
2355          * @param string $action The action to check
2356          * @param User $user User to check
2357          * @param array $errors List of current errors
2358          * @param string $rigor Same format as Title::getUserPermissionsErrors()
2359          * @param bool $short Short circuit on first error
2360          *
2361          * @return array List of errors
2362          */
2363         private function checkReadPermissions( $action, $user, $errors, $rigor, $short ) {
2364                 global $wgWhitelistRead, $wgWhitelistReadRegexp;
2365
2366                 $whitelisted = false;
2367                 if ( User::isEveryoneAllowed( 'read' ) ) {
2368                         # Shortcut for public wikis, allows skipping quite a bit of code
2369                         $whitelisted = true;
2370                 } elseif ( $user->isAllowed( 'read' ) ) {
2371                         # If the user is allowed to read pages, he is allowed to read all pages
2372                         $whitelisted = true;
2373                 } elseif ( $this->isSpecial( 'Userlogin' )
2374                         || $this->isSpecial( 'ChangePassword' )
2375                         || $this->isSpecial( 'PasswordReset' )
2376                 ) {
2377                         # Always grant access to the login page.
2378                         # Even anons need to be able to log in.
2379                         $whitelisted = true;
2380                 } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
2381                         # Time to check the whitelist
2382                         # Only do these checks is there's something to check against
2383                         $name = $this->getPrefixedText();
2384                         $dbName = $this->getPrefixedDBkey();
2385
2386                         // Check for explicit whitelisting with and without underscores
2387                         if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
2388                                 $whitelisted = true;
2389                         } elseif ( $this->getNamespace() == NS_MAIN ) {
2390                                 # Old settings might have the title prefixed with
2391                                 # a colon for main-namespace pages
2392                                 if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
2393                                         $whitelisted = true;
2394                                 }
2395                         } elseif ( $this->isSpecialPage() ) {
2396                                 # If it's a special page, ditch the subpage bit and check again
2397                                 $name = $this->getDBkey();
2398                                 list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
2399                                 if ( $name ) {
2400                                         $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
2401                                         if ( in_array( $pure, $wgWhitelistRead, true ) ) {
2402                                                 $whitelisted = true;
2403                                         }
2404                                 }
2405                         }
2406                 }
2407
2408                 if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && !empty( $wgWhitelistReadRegexp ) ) {
2409                         $name = $this->getPrefixedText();
2410                         // Check for regex whitelisting
2411                         foreach ( $wgWhitelistReadRegexp as $listItem ) {
2412                                 if ( preg_match( $listItem, $name ) ) {
2413                                         $whitelisted = true;
2414                                         break;
2415                                 }
2416                         }
2417                 }
2418
2419                 if ( !$whitelisted ) {
2420                         # If the title is not whitelisted, give extensions a chance to do so...
2421                         Hooks::run( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
2422                         if ( !$whitelisted ) {
2423                                 $errors[] = $this->missingPermissionError( $action, $short );
2424                         }
2425                 }
2426
2427                 return $errors;
2428         }
2429
2430         /**
2431          * Get a description array when the user doesn't have the right to perform
2432          * $action (i.e. when User::isAllowed() returns false)
2433          *
2434          * @param string $action The action to check
2435          * @param bool $short Short circuit on first error
2436          * @return array List of errors
2437          */
2438         private function missingPermissionError( $action, $short ) {
2439                 // We avoid expensive display logic for quickUserCan's and such
2440                 if ( $short ) {
2441                         return array( 'badaccess-group0' );
2442                 }
2443
2444                 $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
2445                         User::getGroupsWithPermission( $action ) );
2446
2447                 if ( count( $groups ) ) {
2448                         global $wgLang;
2449                         return array(
2450                                 'badaccess-groups',
2451                                 $wgLang->commaList( $groups ),
2452                                 count( $groups )
2453                         );
2454                 } else {
2455                         return array( 'badaccess-group0' );
2456                 }
2457         }
2458
2459         /**
2460          * Can $user perform $action on this page? This is an internal function,
2461          * which checks ONLY that previously checked by userCan (i.e. it leaves out
2462          * checks on wfReadOnly() and blocks)
2463          *
2464          * @param string $action Action that permission needs to be checked for
2465          * @param User $user User to check
2466          * @param string $rigor One of (quick,full,secure)
2467          *   - quick  : does cheap permission checks from slaves (usable for GUI creation)
2468          *   - full   : does cheap and expensive checks possibly from a slave
2469          *   - secure : does cheap and expensive checks, using the master as needed
2470          * @param bool $short Set this to true to stop after the first permission error.
2471          * @return array Array of arrays of the arguments to wfMessage to explain permissions problems.
2472          */
2473         protected function getUserPermissionsErrorsInternal(
2474                 $action, $user, $rigor = 'secure', $short = false
2475         ) {
2476                 if ( $rigor === true ) {
2477                         $rigor = 'secure'; // b/c
2478                 } elseif ( $rigor === false ) {
2479                         $rigor = 'quick'; // b/c
2480                 } elseif ( !in_array( $rigor, array( 'quick', 'full', 'secure' ) ) ) {
2481                         throw new Exception( "Invalid rigor parameter '$rigor'." );
2482                 }
2483
2484                 # Read has special handling
2485                 if ( $action == 'read' ) {
2486                         $checks = array(
2487                                 'checkPermissionHooks',
2488                                 'checkReadPermissions',
2489                         );
2490                 # Don't call checkSpecialsAndNSPermissions or checkCSSandJSPermissions
2491                 # here as it will lead to duplicate error messages. This is okay to do
2492                 # since anywhere that checks for create will also check for edit, and
2493                 # those checks are called for edit.
2494                 } elseif ( $action == 'create' ) {
2495                         $checks = array(
2496                                 'checkQuickPermissions',
2497                                 'checkPermissionHooks',
2498                                 'checkPageRestrictions',
2499                                 'checkCascadingSourcesRestrictions',
2500                                 'checkActionPermissions',
2501                                 'checkUserBlock'
2502                         );
2503                 } else {
2504                         $checks = array(
2505                                 'checkQuickPermissions',
2506                                 'checkPermissionHooks',
2507                                 'checkSpecialsAndNSPermissions',
2508                                 'checkCSSandJSPermissions',
2509                                 'checkPageRestrictions',
2510                                 'checkCascadingSourcesRestrictions',
2511                                 'checkActionPermissions',
2512                                 'checkUserBlock'
2513                         );
2514                 }
2515
2516                 $errors = array();
2517                 while ( count( $checks ) > 0 &&
2518                                 !( $short && count( $errors ) > 0 ) ) {
2519                         $method = array_shift( $checks );
2520                         $errors = $this->$method( $action, $user, $errors, $rigor, $short );
2521                 }
2522
2523                 return $errors;
2524         }
2525
2526         /**
2527          * Get a filtered list of all restriction types supported by this wiki.
2528          * @param bool $exists True to get all restriction types that apply to
2529          * titles that do exist, False for all restriction types that apply to
2530          * titles that do not exist
2531          * @return array
2532          */
2533         public static function getFilteredRestrictionTypes( $exists = true ) {
2534                 global $wgRestrictionTypes;
2535                 $types = $wgRestrictionTypes;
2536                 if ( $exists ) {
2537                         # Remove the create restriction for existing titles
2538                         $types = array_diff( $types, array( 'create' ) );
2539                 } else {
2540                         # Only the create and upload restrictions apply to non-existing titles
2541                         $types = array_intersect( $types, array( 'create', 'upload' ) );
2542                 }
2543                 return $types;
2544         }
2545
2546         /**
2547          * Returns restriction types for the current Title
2548          *
2549          * @return array Applicable restriction types
2550          */
2551         public function getRestrictionTypes() {
2552                 if ( $this->isSpecialPage() ) {
2553                         return array();
2554                 }
2555
2556                 $types = self::getFilteredRestrictionTypes( $this->exists() );
2557
2558                 if ( $this->getNamespace() != NS_FILE ) {
2559                         # Remove the upload restriction for non-file titles
2560                         $types = array_diff( $types, array( 'upload' ) );
2561                 }
2562
2563                 Hooks::run( 'TitleGetRestrictionTypes', array( $this, &$types ) );
2564
2565                 wfDebug( __METHOD__ . ': applicable restrictions to [[' .
2566                         $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );
2567
2568                 return $types;
2569         }
2570
2571         /**
2572          * Is this title subject to title protection?
2573          * Title protection is the one applied against creation of such title.
2574          *
2575          * @return array|bool An associative array representing any existent title
2576          *   protection, or false if there's none.
2577          */
2578         public function getTitleProtection() {
2579                 // Can't protect pages in special namespaces
2580                 if ( $this->getNamespace() < 0 ) {
2581                         return false;
2582                 }
2583
2584                 // Can't protect pages that exist.
2585                 if ( $this->exists() ) {
2586                         return false;
2587                 }
2588
2589                 if ( $this->mTitleProtection === null ) {
2590                         $dbr = wfGetDB( DB_SLAVE );
2591                         $res = $dbr->select(
2592                                 'protected_titles',
2593                                 array(
2594                                         'user' => 'pt_user',
2595                                         'reason' => 'pt_reason',
2596                                         'expiry' => 'pt_expiry',
2597                                         'permission' => 'pt_create_perm'
2598                                 ),
2599                                 array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2600                                 __METHOD__
2601                         );
2602
2603                         // fetchRow returns false if there are no rows.
2604                         $row = $dbr->fetchRow( $res );
2605                         if ( $row ) {
2606                                 if ( $row['permission'] == 'sysop' ) {
2607                                         $row['permission'] = 'editprotected'; // B/C
2608                                 }
2609                                 if ( $row['permission'] == 'autoconfirmed' ) {
2610                                         $row['permission'] = 'editsemiprotected'; // B/C
2611                                 }
2612                                 $row['expiry'] = $dbr->decodeExpiry( $row['expiry'] );
2613                         }
2614                         $this->mTitleProtection = $row;
2615                 }
2616                 return $this->mTitleProtection;
2617         }
2618
2619         /**
2620          * Remove any title protection due to page existing
2621          */
2622         public function deleteTitleProtection() {
2623                 $dbw = wfGetDB( DB_MASTER );
2624
2625                 $dbw->delete(
2626                         'protected_titles',
2627                         array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
2628                         __METHOD__
2629                 );
2630                 $this->mTitleProtection = false;
2631         }
2632
2633         /**
2634          * Is this page "semi-protected" - the *only* protection levels are listed
2635          * in $wgSemiprotectedRestrictionLevels?
2636          *
2637          * @param string $action Action to check (default: edit)
2638          * @return bool
2639          */
2640         public function isSemiProtected( $action = 'edit' ) {
2641                 global $wgSemiprotectedRestrictionLevels;
2642
2643                 $restrictions = $this->getRestrictions( $action );
2644                 $semi = $wgSemiprotectedRestrictionLevels;
2645                 if ( !$restrictions || !$semi ) {
2646                         // Not protected, or all protection is full protection
2647                         return false;
2648                 }
2649
2650                 // Remap autoconfirmed to editsemiprotected for BC
2651                 foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
2652                         $semi[$key] = 'editsemiprotected';
2653                 }
2654                 foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key ) {
2655                         $restrictions[$key] = 'editsemiprotected';
2656                 }
2657
2658                 return !array_diff( $restrictions, $semi );
2659         }
2660
2661         /**
2662          * Does the title correspond to a protected article?
2663          *
2664          * @param string $action The action the page is protected from,
2665          * by default checks all actions.
2666          * @return bool
2667          */
2668         public function isProtected( $action = '' ) {
2669                 global $wgRestrictionLevels;
2670
2671                 $restrictionTypes = $this->getRestrictionTypes();
2672
2673                 # Special pages have inherent protection
2674                 if ( $this->isSpecialPage() ) {
2675                         return true;
2676                 }
2677
2678                 # Check regular protection levels
2679                 foreach ( $restrictionTypes as $type ) {
2680                         if ( $action == $type || $action == '' ) {
2681                                 $r = $this->getRestrictions( $type );
2682                                 foreach ( $wgRestrictionLevels as $level ) {
2683                                         if ( in_array( $level, $r ) && $level != '' ) {
2684                                                 return true;
2685                                         }
2686                                 }
2687                         }
2688                 }
2689
2690                 return false;
2691         }
2692
2693         /**
2694          * Determines if $user is unable to edit this page because it has been protected
2695          * by $wgNamespaceProtection.
2696          *
2697          * @param User $user User object to check permissions
2698          * @return bool
2699          */
2700         public function isNamespaceProtected( User $user ) {
2701                 global $wgNamespaceProtection;
2702
2703                 if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
2704                         foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
2705                                 if ( $right != '' && !$user->isAllowed( $right ) ) {
2706                                         return true;
2707                                 }
2708                         }
2709                 }
2710                 return false;
2711         }
2712
2713         /**
2714          * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
2715          *
2716          * @return bool If the page is subject to cascading restrictions.
2717          */
2718         public function isCascadeProtected() {
2719                 list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
2720                 return ( $sources > 0 );
2721         }
2722
2723         /**
2724          * Determines whether cascading protection sources have already been loaded from
2725          * the database.
2726          *
2727          * @param bool $getPages True to check if the pages are loaded, or false to check
2728          * if the status is loaded.
2729          * @return bool Whether or not the specified information has been loaded
2730          * @since 1.23
2731          */
2732         public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
2733                 return $getPages ? $this->mCascadeSources !== null : $this->mHasCascadingRestrictions !== null;
2734         }
2735
2736         /**
2737          * Cascading protection: Get the source of any cascading restrictions on this page.
2738          *
2739          * @param bool $getPages Whether or not to retrieve the actual pages
2740          *        that the restrictions have come from and the actual restrictions
2741          *        themselves.
2742          * @return array Two elements: First is an array of Title objects of the
2743          *        pages from which cascading restrictions have come, false for
2744          *        none, or true if such restrictions exist but $getPages was not
2745          *        set. Second is an array like that returned by
2746          *        Title::getAllRestrictions(), or an empty array if $getPages is
2747          *        false.
2748          */
2749         public function getCascadeProtectionSources( $getPages = true ) {
2750                 $pagerestrictions = array();
2751
2752                 if ( $this->mCascadeSources !== null && $getPages ) {
2753                         return array( $this->mCascadeSources, $this->mCascadingRestrictions );
2754                 } elseif ( $this->mHasCascadingRestrictions !== null && !$getPages ) {
2755                         return array( $this->mHasCascadingRestrictions, $pagerestrictions );
2756                 }
2757
2758                 $dbr = wfGetDB( DB_SLAVE );
2759
2760                 if ( $this->getNamespace() == NS_FILE ) {
2761                         $tables = array( 'imagelinks', 'page_restrictions' );
2762                         $where_clauses = array(
2763                                 'il_to' => $this->getDBkey(),
2764                                 'il_from=pr_page',
2765                                 'pr_cascade' => 1
2766                         );
2767                 } else {
2768                         $tables = array( 'templatelinks', 'page_restrictions' );
2769                         $where_clauses = array(
2770                                 'tl_namespace' => $this->getNamespace(),
2771                                 'tl_title' => $this->getDBkey(),
2772                                 'tl_from=pr_page',
2773                                 'pr_cascade' => 1
2774                         );
2775                 }
2776
2777                 if ( $getPages ) {
2778                         $cols = array( 'pr_page', 'page_namespace', 'page_title',
2779                                 'pr_expiry', 'pr_type', 'pr_level' );
2780                         $where_clauses[] = 'page_id=pr_page';
2781                         $tables[] = 'page';
2782                 } else {
2783                         $cols = array( 'pr_expiry' );
2784                 }
2785
2786                 $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );
2787
2788                 $sources = $getPages ? array() : false;
2789                 $now = wfTimestampNow();
2790
2791                 foreach ( $res as $row ) {
2792                         $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2793                         if ( $expiry > $now ) {
2794                                 if ( $getPages ) {
2795                                         $page_id = $row->pr_page;
2796                                         $page_ns = $row->page_namespace;
2797                                         $page_title = $row->page_title;
2798                                         $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
2799                                         # Add groups needed for each restriction type if its not already there
2800                                         # Make sure this restriction type still exists
2801
2802                                         if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
2803                                                 $pagerestrictions[$row->pr_type] = array();
2804                                         }
2805
2806                                         if (
2807                                                 isset( $pagerestrictions[$row->pr_type] )
2808                                                 && !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] )
2809                                         ) {
2810                                                 $pagerestrictions[$row->pr_type][] = $row->pr_level;
2811                                         }
2812                                 } else {
2813                                         $sources = true;
2814                                 }
2815                         }
2816                 }
2817
2818                 if ( $getPages ) {
2819                         $this->mCascadeSources = $sources;
2820                         $this->mCascadingRestrictions = $pagerestrictions;
2821                 } else {
2822                         $this->mHasCascadingRestrictions = $sources;
2823                 }
2824
2825                 return array( $sources, $pagerestrictions );
2826         }
2827
2828         /**
2829          * Accessor for mRestrictionsLoaded
2830          *
2831          * @return bool Whether or not the page's restrictions have already been
2832          * loaded from the database
2833          * @since 1.23
2834          */
2835         public function areRestrictionsLoaded() {
2836                 return $this->mRestrictionsLoaded;
2837         }
2838
2839         /**
2840          * Accessor/initialisation for mRestrictions
2841          *
2842          * @param string $action Action that permission needs to be checked for
2843          * @return array Restriction levels needed to take the action. All levels are
2844          *     required. Note that restriction levels are normally user rights, but 'sysop'
2845          *     and 'autoconfirmed' are also allowed for backwards compatibility. These should
2846          *     be mapped to 'editprotected' and 'editsemiprotected' respectively.
2847          */
2848         public function getRestrictions( $action ) {
2849                 if ( !$this->mRestrictionsLoaded ) {
2850                         $this->loadRestrictions();
2851                 }
2852                 return isset( $this->mRestrictions[$action] )
2853                                 ? $this->mRestrictions[$action]
2854                                 : array();
2855         }
2856
2857         /**
2858          * Accessor/initialisation for mRestrictions
2859          *
2860          * @return array Keys are actions, values are arrays as returned by
2861          *     Title::getRestrictions()
2862          * @since 1.23
2863          */
2864         public function getAllRestrictions() {
2865                 if ( !$this->mRestrictionsLoaded ) {
2866                         $this->loadRestrictions();
2867                 }
2868                 return $this->mRestrictions;
2869         }
2870
2871         /**
2872          * Get the expiry time for the restriction against a given action
2873          *
2874          * @param string $action
2875          * @return string|bool 14-char timestamp, or 'infinity' if the page is protected forever
2876          *     or not protected at all, or false if the action is not recognised.
2877          */
2878         public function getRestrictionExpiry( $action ) {
2879                 if ( !$this->mRestrictionsLoaded ) {
2880                         $this->loadRestrictions();
2881                 }
2882                 return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
2883         }
2884
2885         /**
2886          * Returns cascading restrictions for the current article
2887          *
2888          * @return bool
2889          */
2890         function areRestrictionsCascading() {
2891                 if ( !$this->mRestrictionsLoaded ) {
2892                         $this->loadRestrictions();
2893                 }
2894
2895                 return $this->mCascadeRestriction;
2896         }
2897
2898         /**
2899          * Loads a string into mRestrictions array
2900          *
2901          * @param ResultWrapper $res Resource restrictions as an SQL result.
2902          * @param string $oldFashionedRestrictions Comma-separated list of page
2903          *        restrictions from page table (pre 1.10)
2904          */
2905         private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
2906                 $rows = array();
2907
2908                 foreach ( $res as $row ) {
2909                         $rows[] = $row;
2910                 }
2911
2912                 $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
2913         }
2914
2915         /**
2916          * Compiles list of active page restrictions from both page table (pre 1.10)
2917          * and page_restrictions table for this existing page.
2918          * Public for usage by LiquidThreads.
2919          *
2920          * @param array $rows Array of db result objects
2921          * @param string $oldFashionedRestrictions Comma-separated list of page
2922          *   restrictions from page table (pre 1.10)
2923          */
2924         public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
2925                 $dbr = wfGetDB( DB_SLAVE );
2926
2927                 $restrictionTypes = $this->getRestrictionTypes();
2928
2929                 foreach ( $restrictionTypes as $type ) {
2930                         $this->mRestrictions[$type] = array();
2931                         $this->mRestrictionsExpiry[$type] = 'infinity';
2932                 }
2933
2934                 $this->mCascadeRestriction = false;
2935
2936                 # Backwards-compatibility: also load the restrictions from the page record (old format).
2937                 if ( $oldFashionedRestrictions !== null ) {
2938                         $this->mOldRestrictions = $oldFashionedRestrictions;
2939                 }
2940
2941                 if ( $this->mOldRestrictions === false ) {
2942                         $this->mOldRestrictions = $dbr->selectField( 'page', 'page_restrictions',
2943                                 array( 'page_id' => $this->getArticleID() ), __METHOD__ );
2944                 }
2945
2946                 if ( $this->mOldRestrictions != '' ) {
2947                         foreach ( explode( ':', trim( $this->mOldRestrictions ) ) as $restrict ) {
2948                                 $temp = explode( '=', trim( $restrict ) );
2949                                 if ( count( $temp ) == 1 ) {
2950                                         // old old format should be treated as edit/move restriction
2951                                         $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
2952                                         $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
2953                                 } else {
2954                                         $restriction = trim( $temp[1] );
2955                                         if ( $restriction != '' ) { // some old entries are empty
2956                                                 $this->mRestrictions[$temp[0]] = explode( ',', $restriction );
2957                                         }
2958                                 }
2959                         }
2960                 }
2961
2962                 if ( count( $rows ) ) {
2963                         # Current system - load second to make them override.
2964                         $now = wfTimestampNow();
2965
2966                         # Cycle through all the restrictions.
2967                         foreach ( $rows as $row ) {
2968
2969                                 // Don't take care of restrictions types that aren't allowed
2970                                 if ( !in_array( $row->pr_type, $restrictionTypes ) ) {
2971                                         continue;
2972                                 }
2973
2974                                 // This code should be refactored, now that it's being used more generally,
2975                                 // But I don't really see any harm in leaving it in Block for now -werdna
2976                                 $expiry = $dbr->decodeExpiry( $row->pr_expiry );
2977
2978                                 // Only apply the restrictions if they haven't expired!
2979                                 if ( !$expiry || $expiry > $now ) {
2980                                         $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
2981                                         $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );
2982
2983                                         $this->mCascadeRestriction |= $row->pr_cascade;
2984                                 }
2985                         }
2986                 }
2987
2988                 $this->mRestrictionsLoaded = true;
2989         }
2990
2991         /**
2992          * Load restrictions from the page_restrictions table
2993          *
2994          * @param string $oldFashionedRestrictions Comma-separated list of page
2995          *   restrictions from page table (pre 1.10)
2996          */
2997         public function loadRestrictions( $oldFashionedRestrictions = null ) {
2998                 if ( !$this->mRestrictionsLoaded ) {
2999                         $dbr = wfGetDB( DB_SLAVE );
3000                         if ( $this->exists() ) {
3001                                 $res = $dbr->select(
3002                                         'page_restrictions',
3003                                         array( 'pr_type', 'pr_expiry', 'pr_level', 'pr_cascade' ),
3004                                         array( 'pr_page' => $this->getArticleID() ),
3005                                         __METHOD__
3006                                 );
3007
3008                                 $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
3009                         } else {
3010                                 $title_protection = $this->getTitleProtection();
3011
3012                                 if ( $title_protection ) {
3013                                         $now = wfTimestampNow();
3014                                         $expiry = $dbr->decodeExpiry( $title_protection['expiry'] );
3015
3016                                         if ( !$expiry || $expiry > $now ) {
3017                                                 // Apply the restrictions
3018                                                 $this->mRestrictionsExpiry['create'] = $expiry;
3019                                                 $this->mRestrictions['create'] = explode( ',', trim( $title_protection['permission'] ) );
3020                                         } else { // Get rid of the old restrictions
3021                                                 $this->mTitleProtection = false;
3022                                         }
3023                                 } else {
3024                                         $this->mRestrictionsExpiry['create'] = 'infinity';
3025                                 }
3026                                 $this->mRestrictionsLoaded = true;
3027                         }
3028                 }
3029         }
3030
3031         /**
3032          * Flush the protection cache in this object and force reload from the database.
3033          * This is used when updating protection from WikiPage::doUpdateRestrictions().
3034          */
3035         public function flushRestrictions() {
3036                 $this->mRestrictionsLoaded = false;
3037                 $this->mTitleProtection = null;
3038         }
3039
3040         /**
3041          * Purge expired restrictions from the page_restrictions table
3042          */
3043         static function purgeExpiredRestrictions() {
3044                 if ( wfReadOnly() ) {
3045                         return;
3046                 }
3047
3048                 $method = __METHOD__;
3049                 $dbw = wfGetDB( DB_MASTER );
3050                 $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
3051                         $dbw->delete(
3052                                 'page_restrictions',
3053                                 array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3054                                 $method
3055                         );
3056                         $dbw->delete(
3057                                 'protected_titles',
3058                                 array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
3059                                 $method
3060                         );
3061                 } );
3062         }
3063
3064         /**
3065          * Does this have subpages?  (Warning, usually requires an extra DB query.)
3066          *
3067          * @return bool
3068          */
3069         public function hasSubpages() {
3070                 if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
3071                         # Duh
3072                         return false;
3073                 }
3074
3075                 # We dynamically add a member variable for the purpose of this method
3076                 # alone to cache the result.  There's no point in having it hanging
3077                 # around uninitialized in every Title object; therefore we only add it
3078                 # if needed and don't declare it statically.
3079                 if ( $this->mHasSubpages === null ) {
3080                         $this->mHasSubpages = false;
3081                         $subpages = $this->getSubpages( 1 );
3082                         if ( $subpages instanceof TitleArray ) {
3083                                 $this->mHasSubpages = (bool)$subpages->count();
3084                         }
3085                 }
3086
3087                 return $this->mHasSubpages;
3088         }
3089
3090         /**
3091          * Get all subpages of this page.
3092          *
3093          * @param int $limit Maximum number of subpages to fetch; -1 for no limit
3094          * @return TitleArray|array TitleArray, or empty array if this page's namespace
3095          *  doesn't allow subpages
3096          */
3097         public function getSubpages( $limit = -1 ) {
3098                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3099                         return array();
3100                 }
3101
3102                 $dbr = wfGetDB( DB_SLAVE );
3103                 $conds['page_namespace'] = $this->getNamespace();
3104                 $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
3105                 $options = array();
3106                 if ( $limit > -1 ) {
3107                         $options['LIMIT'] = $limit;
3108                 }
3109                 $this->mSubpages = TitleArray::newFromResult(
3110                         $dbr->select( 'page',
3111                                 array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
3112                                 $conds,
3113                                 __METHOD__,
3114                                 $options
3115                         )
3116                 );
3117                 return $this->mSubpages;
3118         }
3119
3120         /**
3121          * Is there a version of this page in the deletion archive?
3122          *
3123          * @return int The number of archived revisions
3124          */
3125         public function isDeleted() {
3126                 if ( $this->getNamespace() < 0 ) {
3127                         $n = 0;
3128                 } else {
3129                         $dbr = wfGetDB( DB_SLAVE );
3130
3131                         $n = $dbr->selectField( 'archive', 'COUNT(*)',
3132                                 array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3133                                 __METHOD__
3134                         );
3135                         if ( $this->getNamespace() == NS_FILE ) {
3136                                 $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
3137                                         array( 'fa_name' => $this->getDBkey() ),
3138                                         __METHOD__
3139                                 );
3140                         }
3141                 }
3142                 return (int)$n;
3143         }
3144
3145         /**
3146          * Is there a version of this page in the deletion archive?
3147          *
3148          * @return bool
3149          */
3150         public function isDeletedQuick() {
3151                 if ( $this->getNamespace() < 0 ) {
3152                         return false;
3153                 }
3154                 $dbr = wfGetDB( DB_SLAVE );
3155                 $deleted = (bool)$dbr->selectField( 'archive', '1',
3156                         array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
3157                         __METHOD__
3158                 );
3159                 if ( !$deleted && $this->getNamespace() == NS_FILE ) {
3160                         $deleted = (bool)$dbr->selectField( 'filearchive', '1',
3161                                 array( 'fa_name' => $this->getDBkey() ),
3162                                 __METHOD__
3163                         );
3164                 }
3165                 return $deleted;
3166         }
3167
3168         /**
3169          * Get the article ID for this Title from the link cache,
3170          * adding it if necessary
3171          *
3172          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select
3173          *  for update
3174          * @return int The ID
3175          */
3176         public function getArticleID( $flags = 0 ) {
3177                 if ( $this->getNamespace() < 0 ) {
3178                         $this->mArticleID = 0;
3179                         return $this->mArticleID;
3180                 }
3181                 $linkCache = LinkCache::singleton();
3182                 if ( $flags & self::GAID_FOR_UPDATE ) {
3183                         $oldUpdate = $linkCache->forUpdate( true );
3184                         $linkCache->clearLink( $this );
3185                         $this->mArticleID = $linkCache->addLinkObj( $this );
3186                         $linkCache->forUpdate( $oldUpdate );
3187                 } else {
3188                         if ( -1 == $this->mArticleID ) {
3189                                 $this->mArticleID = $linkCache->addLinkObj( $this );
3190                         }
3191                 }
3192                 return $this->mArticleID;
3193         }
3194
3195         /**
3196          * Is this an article that is a redirect page?
3197          * Uses link cache, adding it if necessary
3198          *
3199          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3200          * @return bool
3201          */
3202         public function isRedirect( $flags = 0 ) {
3203                 if ( !is_null( $this->mRedirect ) ) {
3204                         return $this->mRedirect;
3205                 }
3206                 if ( !$this->getArticleID( $flags ) ) {
3207                         $this->mRedirect = false;
3208                         return $this->mRedirect;
3209                 }
3210
3211                 $linkCache = LinkCache::singleton();
3212                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3213                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'redirect' );
3214                 if ( $cached === null ) {
3215                         # Trust LinkCache's state over our own
3216                         # LinkCache is telling us that the page doesn't exist, despite there being cached
3217                         # data relating to an existing page in $this->mArticleID. Updaters should clear
3218                         # LinkCache as appropriate, or use $flags = Title::GAID_FOR_UPDATE. If that flag is
3219                         # set, then LinkCache will definitely be up to date here, since getArticleID() forces
3220                         # LinkCache to refresh its data from the master.
3221                         $this->mRedirect = false;
3222                         return $this->mRedirect;
3223                 }
3224
3225                 $this->mRedirect = (bool)$cached;
3226
3227                 return $this->mRedirect;
3228         }
3229
3230         /**
3231          * What is the length of this page?
3232          * Uses link cache, adding it if necessary
3233          *
3234          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3235          * @return int
3236          */
3237         public function getLength( $flags = 0 ) {
3238                 if ( $this->mLength != -1 ) {
3239                         return $this->mLength;
3240                 }
3241                 if ( !$this->getArticleID( $flags ) ) {
3242                         $this->mLength = 0;
3243                         return $this->mLength;
3244                 }
3245                 $linkCache = LinkCache::singleton();
3246                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3247                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'length' );
3248                 if ( $cached === null ) {
3249                         # Trust LinkCache's state over our own, as for isRedirect()
3250                         $this->mLength = 0;
3251                         return $this->mLength;
3252                 }
3253
3254                 $this->mLength = intval( $cached );
3255
3256                 return $this->mLength;
3257         }
3258
3259         /**
3260          * What is the page_latest field for this page?
3261          *
3262          * @param int $flags A bit field; may be Title::GAID_FOR_UPDATE to select for update
3263          * @return int Int or 0 if the page doesn't exist
3264          */
3265         public function getLatestRevID( $flags = 0 ) {
3266                 if ( !( $flags & Title::GAID_FOR_UPDATE ) && $this->mLatestID !== false ) {
3267                         return intval( $this->mLatestID );
3268                 }
3269                 if ( !$this->getArticleID( $flags ) ) {
3270                         $this->mLatestID = 0;
3271                         return $this->mLatestID;
3272                 }
3273                 $linkCache = LinkCache::singleton();
3274                 $linkCache->addLinkObj( $this ); # in case we already had an article ID
3275                 $cached = $linkCache->getGoodLinkFieldObj( $this, 'revision' );
3276                 if ( $cached === null ) {
3277                         # Trust LinkCache's state over our own, as for isRedirect()
3278                         $this->mLatestID = 0;
3279                         return $this->mLatestID;
3280                 }
3281
3282                 $this->mLatestID = intval( $cached );
3283
3284                 return $this->mLatestID;
3285         }
3286
3287         /**
3288          * This clears some fields in this object, and clears any associated
3289          * keys in the "bad links" section of the link cache.
3290          *
3291          * - This is called from WikiPage::doEdit() and WikiPage::insertOn() to allow
3292          * loading of the new page_id. It's also called from
3293          * WikiPage::doDeleteArticleReal()
3294          *
3295          * @param int $newid The new Article ID
3296          */
3297         public function resetArticleID( $newid ) {
3298                 $linkCache = LinkCache::singleton();
3299                 $linkCache->clearLink( $this );
3300
3301                 if ( $newid === false ) {
3302                         $this->mArticleID = -1;
3303                 } else {
3304                         $this->mArticleID = intval( $newid );
3305                 }
3306                 $this->mRestrictionsLoaded = false;
3307                 $this->mRestrictions = array();
3308                 $this->mOldRestrictions = false;
3309                 $this->mRedirect = null;
3310                 $this->mLength = -1;
3311                 $this->mLatestID = false;
3312                 $this->mContentModel = false;
3313                 $this->mEstimateRevisions = null;
3314                 $this->mPageLanguage = false;
3315                 $this->mDbPageLanguage = null;
3316                 $this->mIsBigDeletion = null;
3317         }
3318
3319         public static function clearCaches() {
3320                 $linkCache = LinkCache::singleton();
3321                 $linkCache->clear();
3322
3323                 $titleCache = self::getTitleCache();
3324                 $titleCache->clear();
3325         }
3326
3327         /**
3328          * Capitalize a text string for a title if it belongs to a namespace that capitalizes
3329          *
3330          * @param string $text Containing title to capitalize
3331          * @param int $ns Namespace index, defaults to NS_MAIN
3332          * @return string Containing capitalized title
3333          */
3334         public static function capitalize( $text, $ns = NS_MAIN ) {
3335                 global $wgContLang;
3336
3337                 if ( MWNamespace::isCapitalized( $ns ) ) {
3338                         return $wgContLang->ucfirst( $text );
3339                 } else {
3340                         return $text;
3341                 }
3342         }
3343
3344         /**
3345          * Secure and split - main initialisation function for this object
3346          *
3347          * Assumes that mDbkeyform has been set, and is urldecoded
3348          * and uses underscores, but not otherwise munged.  This function
3349          * removes illegal characters, splits off the interwiki and
3350          * namespace prefixes, sets the other forms, and canonicalizes
3351          * everything.
3352          *
3353          * @throws MalformedTitleException On invalid titles
3354          * @return bool True on success
3355          */
3356         private function secureAndSplit() {
3357                 # Initialisation
3358                 $this->mInterwiki = '';
3359                 $this->mFragment = '';
3360                 $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
3361
3362                 $dbkey = $this->mDbkeyform;
3363
3364                 // @note: splitTitleString() is a temporary hack to allow MediaWikiTitleCodec to share
3365                 //        the parsing code with Title, while avoiding massive refactoring.
3366                 // @todo: get rid of secureAndSplit, refactor parsing code.
3367                 $titleParser = self::getTitleParser();
3368                 // MalformedTitleException can be thrown here
3369                 $parts = $titleParser->splitTitleString( $dbkey, $this->getDefaultNamespace() );
3370
3371                 # Fill fields
3372                 $this->setFragment( '#' . $parts['fragment'] );
3373                 $this->mInterwiki = $parts['interwiki'];
3374                 $this->mLocalInterwiki = $parts['local_interwiki'];
3375                 $this->mNamespace = $parts['namespace'];
3376                 $this->mUserCaseDBKey = $parts['user_case_dbkey'];
3377
3378                 $this->mDbkeyform = $parts['dbkey'];
3379                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
3380                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
3381
3382                 # We already know that some pages won't be in the database!
3383                 if ( $this->isExternal() || $this->mNamespace == NS_SPECIAL ) {
3384                         $this->mArticleID = 0;
3385                 }
3386
3387                 return true;
3388         }
3389
3390         /**
3391          * Get an array of Title objects linking to this Title
3392          * Also stores the IDs in the link cache.
3393          *
3394          * WARNING: do not use this function on arbitrary user-supplied titles!
3395          * On heavily-used templates it will max out the memory.
3396          *
3397          * @param array $options May be FOR UPDATE
3398          * @param string $table Table name
3399          * @param string $prefix Fields prefix
3400          * @return Title[] Array of Title objects linking here
3401          */
3402         public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3403                 if ( count( $options ) > 0 ) {
3404                         $db = wfGetDB( DB_MASTER );
3405                 } else {
3406                         $db = wfGetDB( DB_SLAVE );
3407                 }
3408
3409                 $res = $db->select(
3410                         array( 'page', $table ),
3411                         self::getSelectFields(),
3412                         array(
3413                                 "{$prefix}_from=page_id",
3414                                 "{$prefix}_namespace" => $this->getNamespace(),
3415                                 "{$prefix}_title" => $this->getDBkey() ),
3416                         __METHOD__,
3417                         $options
3418                 );
3419
3420                 $retVal = array();
3421                 if ( $res->numRows() ) {
3422                         $linkCache = LinkCache::singleton();
3423                         foreach ( $res as $row ) {
3424                                 $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
3425                                 if ( $titleObj ) {
3426                                         $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
3427                                         $retVal[] = $titleObj;
3428                                 }
3429                         }
3430                 }
3431                 return $retVal;
3432         }
3433
3434         /**
3435          * Get an array of Title objects using this Title as a template
3436          * Also stores the IDs in the link cache.
3437          *
3438          * WARNING: do not use this function on arbitrary user-supplied titles!
3439          * On heavily-used templates it will max out the memory.
3440          *
3441          * @param array $options May be FOR UPDATE
3442          * @return Title[] Array of Title the Title objects linking here
3443          */
3444         public function getTemplateLinksTo( $options = array() ) {
3445                 return $this->getLinksTo( $options, 'templatelinks', 'tl' );
3446         }
3447
3448         /**
3449          * Get an array of Title objects linked from this Title
3450          * Also stores the IDs in the link cache.
3451          *
3452          * WARNING: do not use this function on arbitrary user-supplied titles!
3453          * On heavily-used templates it will max out the memory.
3454          *
3455          * @param array $options May be FOR UPDATE
3456          * @param string $table Table name
3457          * @param string $prefix Fields prefix
3458          * @return array Array of Title objects linking here
3459          */
3460         public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
3461                 $id = $this->getArticleID();
3462
3463                 # If the page doesn't exist; there can't be any link from this page
3464                 if ( !$id ) {
3465                         return array();
3466                 }
3467
3468                 if ( count( $options ) > 0 ) {
3469                         $db = wfGetDB( DB_MASTER );
3470                 } else {
3471                         $db = wfGetDB( DB_SLAVE );
3472                 }
3473
3474                 $blNamespace = "{$prefix}_namespace";
3475                 $blTitle = "{$prefix}_title";
3476
3477                 $res = $db->select(
3478                         array( $table, 'page' ),
3479                         array_merge(
3480                                 array( $blNamespace, $blTitle ),
3481                                 WikiPage::selectFields()
3482                         ),
3483                         array( "{$prefix}_from" => $id ),
3484                         __METHOD__,
3485                         $options,
3486                         array( 'page' => array(
3487                                 'LEFT JOIN',
3488                                 array( "page_namespace=$blNamespace", "page_title=$blTitle" )
3489                         ) )
3490                 );
3491
3492                 $retVal = array();
3493                 $linkCache = LinkCache::singleton();
3494                 foreach ( $res as $row ) {
3495                         if ( $row->page_id ) {
3496                                 $titleObj = Title::newFromRow( $row );
3497                         } else {
3498                                 $titleObj = Title::makeTitle( $row->$blNamespace, $row->$blTitle );
3499                                 $linkCache->addBadLinkObj( $titleObj );
3500                         }
3501                         $retVal[] = $titleObj;
3502                 }
3503
3504                 return $retVal;
3505         }
3506
3507         /**
3508          * Get an array of Title objects used on this Title as a template
3509          * Also stores the IDs in the link cache.
3510          *
3511          * WARNING: do not use this function on arbitrary user-supplied titles!
3512          * On heavily-used templates it will max out the memory.
3513          *
3514          * @param array $options May be FOR UPDATE
3515          * @return Title[] Array of Title the Title objects used here
3516          */
3517         public function getTemplateLinksFrom( $options = array() ) {
3518                 return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
3519         }
3520
3521         /**
3522          * Get an array of Title objects referring to non-existent articles linked
3523          * from this page.
3524          *
3525          * @todo check if needed (used only in SpecialBrokenRedirects.php, and
3526          *   should use redirect table in this case).
3527          * @return Title[] Array of Title the Title objects
3528          */
3529         public function getBrokenLinksFrom() {
3530                 if ( $this->getArticleID() == 0 ) {
3531                         # All links from article ID 0 are false positives
3532                         return array();
3533                 }
3534
3535                 $dbr = wfGetDB( DB_SLAVE );
3536                 $res = $dbr->select(
3537                         array( 'page', 'pagelinks' ),
3538                         array( 'pl_namespace', 'pl_title' ),
3539                         array(
3540                                 'pl_from' => $this->getArticleID(),
3541                                 'page_namespace IS NULL'
3542                         ),
3543                         __METHOD__, array(),
3544                         array(
3545                                 'page' => array(
3546                                         'LEFT JOIN',
3547                                         array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
3548                                 )
3549                         )
3550                 );
3551
3552                 $retVal = array();
3553                 foreach ( $res as $row ) {
3554                         $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
3555                 }
3556                 return $retVal;
3557         }
3558
3559         /**
3560          * Get a list of URLs to purge from the CDN cache when this
3561          * page changes
3562          *
3563          * @return string[] Array of String the URLs
3564          */
3565         public function getCdnUrls() {
3566                 $urls = array(
3567                         $this->getInternalURL(),
3568                         $this->getInternalURL( 'action=history' )
3569                 );
3570
3571                 $pageLang = $this->getPageLanguage();
3572                 if ( $pageLang->hasVariants() ) {
3573                         $variants = $pageLang->getVariants();
3574                         foreach ( $variants as $vCode ) {
3575                                 $urls[] = $this->getInternalURL( '', $vCode );
3576                         }
3577                 }
3578
3579                 // If we are looking at a css/js user subpage, purge the action=raw.
3580                 if ( $this->isJsSubpage() ) {
3581                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/javascript' );
3582                 } elseif ( $this->isCssSubpage() ) {
3583                         $urls[] = $this->getInternalUrl( 'action=raw&ctype=text/css' );
3584                 }
3585
3586                 Hooks::run( 'TitleSquidURLs', array( $this, &$urls ) );
3587                 return $urls;
3588         }
3589
3590         /**
3591          * @deprecated since 1.27 use getCdnUrls()
3592          */
3593         public function getSquidURLs() {
3594                 return $this->getCdnUrls();
3595         }
3596
3597         /**
3598          * Purge all applicable CDN URLs
3599          */
3600         public function purgeSquid() {
3601                 DeferredUpdates::addUpdate(
3602                         new CdnCacheUpdate( $this->getCdnUrls() ),
3603                         DeferredUpdates::PRESEND
3604                 );
3605         }
3606
3607         /**
3608          * Move this page without authentication
3609          *
3610          * @deprecated since 1.25 use MovePage class instead
3611          * @param Title $nt The new page Title
3612          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3613          */
3614         public function moveNoAuth( &$nt ) {
3615                 wfDeprecated( __METHOD__, '1.25' );
3616                 return $this->moveTo( $nt, false );
3617         }
3618
3619         /**
3620          * Check whether a given move operation would be valid.
3621          * Returns true if ok, or a getUserPermissionsErrors()-like array otherwise
3622          *
3623          * @deprecated since 1.25, use MovePage's methods instead
3624          * @param Title $nt The new title
3625          * @param bool $auth Whether to check user permissions (uses $wgUser)
3626          * @param string $reason Is the log summary of the move, used for spam checking
3627          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3628          */
3629         public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
3630                 global $wgUser;
3631
3632                 if ( !( $nt instanceof Title ) ) {
3633                         // Normally we'd add this to $errors, but we'll get
3634                         // lots of syntax errors if $nt is not an object
3635                         return array( array( 'badtitletext' ) );
3636                 }
3637
3638                 $mp = new MovePage( $this, $nt );
3639                 $errors = $mp->isValidMove()->getErrorsArray();
3640                 if ( $auth ) {
3641                         $errors = wfMergeErrorArrays(
3642                                 $errors,
3643                                 $mp->checkPermissions( $wgUser, $reason )->getErrorsArray()
3644                         );
3645                 }
3646
3647                 return $errors ?: true;
3648         }
3649
3650         /**
3651          * Check if the requested move target is a valid file move target
3652          * @todo move this to MovePage
3653          * @param Title $nt Target title
3654          * @return array List of errors
3655          */
3656         protected function validateFileMoveOperation( $nt ) {
3657                 global $wgUser;
3658
3659                 $errors = array();
3660
3661                 $destFile = wfLocalFile( $nt );
3662                 $destFile->load( File::READ_LATEST );
3663                 if ( !$wgUser->isAllowed( 'reupload-shared' )
3664                         && !$destFile->exists() && wfFindFile( $nt )
3665                 ) {
3666                         $errors[] = array( 'file-exists-sharedrepo' );
3667                 }
3668
3669                 return $errors;
3670         }
3671
3672         /**
3673          * Move a title to a new location
3674          *
3675          * @deprecated since 1.25, use the MovePage class instead
3676          * @param Title $nt The new title
3677          * @param bool $auth Indicates whether $wgUser's permissions
3678          *  should be checked
3679          * @param string $reason The reason for the move
3680          * @param bool $createRedirect Whether to create a redirect from the old title to the new title.
3681          *  Ignored if the user doesn't have the suppressredirect right.
3682          * @return array|bool True on success, getUserPermissionsErrors()-like array on failure
3683          */
3684         public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
3685                 global $wgUser;
3686                 $err = $this->isValidMoveOperation( $nt, $auth, $reason );
3687                 if ( is_array( $err ) ) {
3688                         // Auto-block user's IP if the account was "hard" blocked
3689                         $wgUser->spreadAnyEditBlock();
3690                         return $err;
3691                 }
3692                 // Check suppressredirect permission
3693                 if ( $auth && !$wgUser->isAllowed( 'suppressredirect' ) ) {
3694                         $createRedirect = true;
3695                 }
3696
3697                 $mp = new MovePage( $this, $nt );
3698                 $status = $mp->move( $wgUser, $reason, $createRedirect );
3699                 if ( $status->isOK() ) {
3700                         return true;
3701                 } else {
3702                         return $status->getErrorsArray();
3703                 }
3704         }
3705
3706         /**
3707          * Move this page's subpages to be subpages of $nt
3708          *
3709          * @param Title $nt Move target
3710          * @param bool $auth Whether $wgUser's permissions should be checked
3711          * @param string $reason The reason for the move
3712          * @param bool $createRedirect Whether to create redirects from the old subpages to
3713          *     the new ones Ignored if the user doesn't have the 'suppressredirect' right
3714          * @return array Array with old page titles as keys, and strings (new page titles) or
3715          *     arrays (errors) as values, or an error array with numeric indices if no pages
3716          *     were moved
3717          */
3718         public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
3719                 global $wgMaximumMovedPages;
3720                 // Check permissions
3721                 if ( !$this->userCan( 'move-subpages' ) ) {
3722                         return array( 'cant-move-subpages' );
3723                 }
3724                 // Do the source and target namespaces support subpages?
3725                 if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
3726                         return array( 'namespace-nosubpages',
3727                                 MWNamespace::getCanonicalName( $this->getNamespace() ) );
3728                 }
3729                 if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
3730                         return array( 'namespace-nosubpages',
3731                                 MWNamespace::getCanonicalName( $nt->getNamespace() ) );
3732                 }
3733
3734                 $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
3735                 $retval = array();
3736                 $count = 0;
3737                 foreach ( $subpages as $oldSubpage ) {
3738                         $count++;
3739                         if ( $count > $wgMaximumMovedPages ) {
3740                                 $retval[$oldSubpage->getPrefixedText()] =
3741                                                 array( 'movepage-max-pages',
3742                                                         $wgMaximumMovedPages );
3743                                 break;
3744                         }
3745
3746                         // We don't know whether this function was called before
3747                         // or after moving the root page, so check both
3748                         // $this and $nt
3749                         if ( $oldSubpage->getArticleID() == $this->getArticleID()
3750                                 || $oldSubpage->getArticleID() == $nt->getArticleID()
3751                         ) {
3752                                 // When moving a page to a subpage of itself,
3753                                 // don't move it twice
3754                                 continue;
3755                         }
3756                         $newPageName = preg_replace(
3757                                         '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
3758                                         StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
3759                                         $oldSubpage->getDBkey() );
3760                         if ( $oldSubpage->isTalkPage() ) {
3761                                 $newNs = $nt->getTalkPage()->getNamespace();
3762                         } else {
3763                                 $newNs = $nt->getSubjectPage()->getNamespace();
3764                         }
3765                         # Bug 14385: we need makeTitleSafe because the new page names may
3766                         # be longer than 255 characters.
3767                         $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );
3768
3769                         $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
3770                         if ( $success === true ) {
3771                                 $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
3772                         } else {
3773                                 $retval[$oldSubpage->getPrefixedText()] = $success;
3774                         }
3775                 }
3776                 return $retval;
3777         }
3778
3779         /**
3780          * Checks if this page is just a one-rev redirect.
3781          * Adds lock, so don't use just for light purposes.
3782          *
3783          * @return bool
3784          */
3785         public function isSingleRevRedirect() {
3786                 global $wgContentHandlerUseDB;
3787
3788                 $dbw = wfGetDB( DB_MASTER );
3789
3790                 # Is it a redirect?
3791                 $fields = array( 'page_is_redirect', 'page_latest', 'page_id' );
3792                 if ( $wgContentHandlerUseDB ) {
3793                         $fields[] = 'page_content_model';
3794                 }
3795
3796                 $row = $dbw->selectRow( 'page',
3797                         $fields,
3798                         $this->pageCond(),
3799                         __METHOD__,
3800                         array( 'FOR UPDATE' )
3801                 );
3802                 # Cache some fields we may want
3803                 $this->mArticleID = $row ? intval( $row->page_id ) : 0;
3804                 $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
3805                 $this->mLatestID = $row ? intval( $row->page_latest ) : false;
3806                 $this->mContentModel = $row && isset( $row->page_content_model )
3807                         ? strval( $row->page_content_model )
3808                         : false;
3809
3810                 if ( !$this->mRedirect ) {
3811                         return false;
3812                 }
3813                 # Does the article have a history?
3814                 $row = $dbw->selectField( array( 'page', 'revision' ),
3815                         'rev_id',
3816                         array( 'page_namespace' => $this->getNamespace(),
3817                                 'page_title' => $this->getDBkey(),
3818                                 'page_id=rev_page',
3819                                 'page_latest != rev_id'
3820                         ),
3821                         __METHOD__,
3822                         array( 'FOR UPDATE' )
3823                 );
3824                 # Return true if there was no history
3825                 return ( $row === false );
3826         }
3827
3828         /**
3829          * Checks if $this can be moved to a given Title
3830          * - Selects for update, so don't call it unless you mean business
3831          *
3832          * @deprecated since 1.25, use MovePage's methods instead
3833          * @param Title $nt The new title to check
3834          * @return bool
3835          */
3836         public function isValidMoveTarget( $nt ) {
3837                 # Is it an existing file?
3838                 if ( $nt->getNamespace() == NS_FILE ) {
3839                         $file = wfLocalFile( $nt );
3840                         $file->load( File::READ_LATEST );
3841                         if ( $file->exists() ) {
3842                                 wfDebug( __METHOD__ . ": file exists\n" );
3843                                 return false;
3844                         }
3845                 }
3846                 # Is it a redirect with no history?
3847                 if ( !$nt->isSingleRevRedirect() ) {
3848                         wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
3849                         return false;
3850                 }
3851                 # Get the article text
3852                 $rev = Revision::newFromTitle( $nt, false, Revision::READ_LATEST );
3853                 if ( !is_object( $rev ) ) {
3854                         return false;
3855                 }
3856                 $content = $rev->getContent();
3857                 # Does the redirect point to the source?
3858                 # Or is it a broken self-redirect, usually caused by namespace collisions?
3859                 $redirTitle = $content ? $content->getRedirectTarget() : null;
3860
3861                 if ( $redirTitle ) {
3862                         if ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
3863                                 $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) {
3864                                 wfDebug( __METHOD__ . ": redirect points to other page\n" );
3865                                 return false;
3866                         } else {
3867                                 return true;
3868                         }
3869                 } else {
3870                         # Fail safe (not a redirect after all. strange.)
3871                         wfDebug( __METHOD__ . ": failsafe: database sais " . $nt->getPrefixedDBkey() .
3872                                                 " is a redirect, but it doesn't contain a valid redirect.\n" );
3873                         return false;
3874                 }
3875         }
3876
3877         /**
3878          * Get categories to which this Title belongs and return an array of
3879          * categories' names.
3880          *
3881          * @return array Array of parents in the form:
3882          *        $parent => $currentarticle
3883          */
3884         public function getParentCategories() {
3885                 global $wgContLang;
3886
3887                 $data = array();
3888
3889                 $titleKey = $this->getArticleID();
3890
3891                 if ( $titleKey === 0 ) {
3892                         return $data;
3893                 }
3894
3895                 $dbr = wfGetDB( DB_SLAVE );
3896
3897                 $res = $dbr->select(
3898                         'categorylinks',
3899                         'cl_to',
3900                         array( 'cl_from' => $titleKey ),
3901                         __METHOD__
3902                 );
3903
3904                 if ( $res->numRows() > 0 ) {
3905                         foreach ( $res as $row ) {
3906                                 // $data[] = Title::newFromText($wgContLang->getNsText ( NS_CATEGORY ).':'.$row->cl_to);
3907                                 $data[$wgContLang->getNsText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
3908                         }
3909                 }
3910                 return $data;
3911         }
3912
3913         /**
3914          * Get a tree of parent categories
3915          *
3916          * @param array $children Array with the children in the keys, to check for circular refs
3917          * @return array Tree of parent categories
3918          */
3919         public function getParentCategoryTree( $children = array() ) {
3920                 $stack = array();
3921                 $parents = $this->getParentCategories();
3922
3923                 if ( $parents ) {
3924                         foreach ( $parents as $parent => $current ) {
3925                                 if ( array_key_exists( $parent, $children ) ) {
3926                                         # Circular reference
3927                                         $stack[$parent] = array();
3928                                 } else {
3929                                         $nt = Title::newFromText( $parent );
3930                                         if ( $nt ) {
3931                                                 $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
3932                                         }
3933                                 }
3934                         }
3935                 }
3936
3937                 return $stack;
3938         }
3939
3940         /**
3941          * Get an associative array for selecting this title from
3942          * the "page" table
3943          *
3944          * @return array Array suitable for the $where parameter of DB::select()
3945          */
3946         public function pageCond() {
3947                 if ( $this->mArticleID > 0 ) {
3948                         // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
3949                         return array( 'page_id' => $this->mArticleID );
3950                 } else {
3951                         return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
3952                 }
3953         }
3954
3955         /**
3956          * Get the revision ID of the previous revision
3957          *
3958          * @param int $revId Revision ID. Get the revision that was before this one.
3959          * @param int $flags Title::GAID_FOR_UPDATE
3960          * @return int|bool Old revision ID, or false if none exists
3961          */
3962         public function getPreviousRevisionID( $revId, $flags = 0 ) {
3963                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3964                 $revId = $db->selectField( 'revision', 'rev_id',
3965                         array(
3966                                 'rev_page' => $this->getArticleID( $flags ),
3967                                 'rev_id < ' . intval( $revId )
3968                         ),
3969                         __METHOD__,
3970                         array( 'ORDER BY' => 'rev_id DESC' )
3971                 );
3972
3973                 if ( $revId === false ) {
3974                         return false;
3975                 } else {
3976                         return intval( $revId );
3977                 }
3978         }
3979
3980         /**
3981          * Get the revision ID of the next revision
3982          *
3983          * @param int $revId Revision ID. Get the revision that was after this one.
3984          * @param int $flags Title::GAID_FOR_UPDATE
3985          * @return int|bool Next revision ID, or false if none exists
3986          */
3987         public function getNextRevisionID( $revId, $flags = 0 ) {
3988                 $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
3989                 $revId = $db->selectField( 'revision', 'rev_id',
3990                         array(
3991                                 'rev_page' => $this->getArticleID( $flags ),
3992                                 'rev_id > ' . intval( $revId )
3993                         ),
3994                         __METHOD__,
3995                         array( 'ORDER BY' => 'rev_id' )
3996                 );
3997
3998                 if ( $revId === false ) {
3999                         return false;
4000                 } else {
4001                         return intval( $revId );
4002                 }
4003         }
4004
4005         /**
4006          * Get the first revision of the page
4007          *
4008          * @param int $flags Title::GAID_FOR_UPDATE
4009          * @return Revision|null If page doesn't exist
4010          */
4011         public function getFirstRevision( $flags = 0 ) {
4012                 $pageId = $this->getArticleID( $flags );
4013                 if ( $pageId ) {
4014                         $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
4015                         $row = $db->selectRow( 'revision', Revision::selectFields(),
4016                                 array( 'rev_page' => $pageId ),
4017                                 __METHOD__,
4018                                 array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
4019                         );
4020                         if ( $row ) {
4021                                 return new Revision( $row );
4022                         }
4023                 }
4024                 return null;
4025         }
4026
4027         /**
4028          * Get the oldest revision timestamp of this page
4029          *
4030          * @param int $flags Title::GAID_FOR_UPDATE
4031          * @return string MW timestamp
4032          */
4033         public function getEarliestRevTime( $flags = 0 ) {
4034                 $rev = $this->getFirstRevision( $flags );
4035                 return $rev ? $rev->getTimestamp() : null;
4036         }
4037
4038         /**
4039          * Check if this is a new page
4040          *
4041          * @return bool
4042          */
4043         public function isNewPage() {
4044                 $dbr = wfGetDB( DB_SLAVE );
4045                 return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
4046         }
4047
4048         /**
4049          * Check whether the number of revisions of this page surpasses $wgDeleteRevisionsLimit
4050          *
4051          * @return bool
4052          */
4053         public function isBigDeletion() {
4054                 global $wgDeleteRevisionsLimit;
4055
4056                 if ( !$wgDeleteRevisionsLimit ) {
4057                         return false;
4058                 }
4059
4060                 if ( $this->mIsBigDeletion === null ) {
4061                         $dbr = wfGetDB( DB_SLAVE );
4062
4063                         $revCount = $dbr->selectRowCount(
4064                                 'revision',
4065                                 '1',
4066                                 array( 'rev_page' => $this->getArticleID() ),
4067                                 __METHOD__,
4068                                 array( 'LIMIT' => $wgDeleteRevisionsLimit + 1 )
4069                         );
4070
4071                         $this->mIsBigDeletion = $revCount > $wgDeleteRevisionsLimit;
4072                 }
4073
4074                 return $this->mIsBigDeletion;
4075         }
4076
4077         /**
4078          * Get the approximate revision count of this page.
4079          *
4080          * @return int
4081          */
4082         public function estimateRevisionCount() {
4083                 if ( !$this->exists() ) {
4084                         return 0;
4085                 }
4086
4087                 if ( $this->mEstimateRevisions === null ) {
4088                         $dbr = wfGetDB( DB_SLAVE );
4089                         $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
4090                                 array( 'rev_page' => $this->getArticleID() ), __METHOD__ );
4091                 }
4092
4093                 return $this->mEstimateRevisions;
4094         }
4095
4096         /**
4097          * Get the number of revisions between the given revision.
4098          * Used for diffs and other things that really need it.
4099          *
4100          * @param int|Revision $old Old revision or rev ID (first before range)
4101          * @param int|Revision $new New revision or rev ID (first after range)
4102          * @param int|null $max Limit of Revisions to count, will be incremented to detect truncations
4103          * @return int Number of revisions between these revisions.
4104          */
4105         public function countRevisionsBetween( $old, $new, $max = null ) {
4106                 if ( !( $old instanceof Revision ) ) {
4107                         $old = Revision::newFromTitle( $this, (int)$old );
4108                 }
4109                 if ( !( $new instanceof Revision ) ) {
4110                         $new = Revision::newFromTitle( $this, (int)$new );
4111                 }
4112                 if ( !$old || !$new ) {
4113                         return 0; // nothing to compare
4114                 }
4115                 $dbr = wfGetDB( DB_SLAVE );
4116                 $conds = array(
4117                         'rev_page' => $this->getArticleID(),
4118                         'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4119                         'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4120                 );
4121                 if ( $max !== null ) {
4122                         return $dbr->selectRowCount( 'revision', '1',
4123                                 $conds,
4124                                 __METHOD__,
4125                                 array( 'LIMIT' => $max + 1 ) // extra to detect truncation
4126                         );
4127                 } else {
4128                         return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
4129                 }
4130         }
4131
4132         /**
4133          * Get the authors between the given revisions or revision IDs.
4134          * Used for diffs and other things that really need it.
4135          *
4136          * @since 1.23
4137          *
4138          * @param int|Revision $old Old revision or rev ID (first before range by default)
4139          * @param int|Revision $new New revision or rev ID (first after range by default)
4140          * @param int $limit Maximum number of authors
4141          * @param string|array $options (Optional): Single option, or an array of options:
4142          *     'include_old' Include $old in the range; $new is excluded.
4143          *     'include_new' Include $new in the range; $old is excluded.
4144          *     'include_both' Include both $old and $new in the range.
4145          *     Unknown option values are ignored.
4146          * @return array|null Names of revision authors in the range; null if not both revisions exist
4147          */
4148         public function getAuthorsBetween( $old, $new, $limit, $options = array() ) {
4149                 if ( !( $old instanceof Revision ) ) {
4150                         $old = Revision::newFromTitle( $this, (int)$old );
4151                 }
4152                 if ( !( $new instanceof Revision ) ) {
4153                         $new = Revision::newFromTitle( $this, (int)$new );
4154                 }
4155                 // XXX: what if Revision objects are passed in, but they don't refer to this title?
4156                 // Add $old->getPage() != $new->getPage() || $old->getPage() != $this->getArticleID()
4157                 // in the sanity check below?
4158                 if ( !$old || !$new ) {
4159                         return null; // nothing to compare
4160                 }
4161                 $authors = array();
4162                 $old_cmp = '>';
4163                 $new_cmp = '<';
4164                 $options = (array)$options;
4165                 if ( in_array( 'include_old', $options ) ) {
4166                         $old_cmp = '>=';
4167                 }
4168                 if ( in_array( 'include_new', $options ) ) {
4169                         $new_cmp = '<=';
4170                 }
4171                 if ( in_array( 'include_both', $options ) ) {
4172                         $old_cmp = '>=';
4173                         $new_cmp = '<=';
4174                 }
4175                 // No DB query needed if $old and $new are the same or successive revisions:
4176                 if ( $old->getId() === $new->getId() ) {
4177                         return ( $old_cmp === '>' && $new_cmp === '<' ) ?
4178                                 array() :
4179                                 array( $old->getUserText( Revision::RAW ) );
4180                 } elseif ( $old->getId() === $new->getParentId() ) {
4181                         if ( $old_cmp === '>=' && $new_cmp === '<=' ) {
4182                                 $authors[] = $old->getUserText( Revision::RAW );
4183                                 if ( $old->getUserText( Revision::RAW ) != $new->getUserText( Revision::RAW ) ) {
4184                                         $authors[] = $new->getUserText( Revision::RAW );
4185                                 }
4186                         } elseif ( $old_cmp === '>=' ) {
4187                                 $authors[] = $old->getUserText( Revision::RAW );
4188                         } elseif ( $new_cmp === '<=' ) {
4189                                 $authors[] = $new->getUserText( Revision::RAW );
4190                         }
4191                         return $authors;
4192                 }
4193                 $dbr = wfGetDB( DB_SLAVE );
4194                 $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
4195                         array(
4196                                 'rev_page' => $this->getArticleID(),
4197                                 "rev_timestamp $old_cmp " . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
4198                                 "rev_timestamp $new_cmp " . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
4199                         ), __METHOD__,
4200                         array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
4201                 );
4202                 foreach ( $res as $row ) {
4203                         $authors[] = $row->rev_user_text;
4204                 }
4205                 return $authors;
4206         }
4207
4208         /**
4209          * Get the number of authors between the given revisions or revision IDs.
4210          * Used for diffs and other things that really need it.
4211          *
4212          * @param int|Revision $old Old revision or rev ID (first before range by default)
4213          * @param int|Revision $new New revision or rev ID (first after range by default)
4214          * @param int $limit Maximum number of authors
4215          * @param string|array $options (Optional): Single option, or an array of options:
4216          *     'include_old' Include $old in the range; $new is excluded.
4217          *     'include_new' Include $new in the range; $old is excluded.
4218          *     'include_both' Include both $old and $new in the range.
4219          *     Unknown option values are ignored.
4220          * @return int Number of revision authors in the range; zero if not both revisions exist
4221          */
4222         public function countAuthorsBetween( $old, $new, $limit, $options = array() ) {
4223                 $authors = $this->getAuthorsBetween( $old, $new, $limit, $options );
4224                 return $authors ? count( $authors ) : 0;
4225         }
4226
4227         /**
4228          * Compare with another title.
4229          *
4230          * @param Title $title
4231          * @return bool
4232          */
4233         public function equals( Title $title ) {
4234                 // Note: === is necessary for proper matching of number-like titles.
4235                 return $this->getInterwiki() === $title->getInterwiki()
4236                         && $this->getNamespace() == $title->getNamespace()
4237                         && $this->getDBkey() === $title->getDBkey();
4238         }
4239
4240         /**
4241          * Check if this title is a subpage of another title
4242          *
4243          * @param Title $title
4244          * @return bool
4245          */
4246         public function isSubpageOf( Title $title ) {
4247                 return $this->getInterwiki() === $title->getInterwiki()
4248                         && $this->getNamespace() == $title->getNamespace()
4249                         && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
4250         }
4251
4252         /**
4253          * Check if page exists.  For historical reasons, this function simply
4254          * checks for the existence of the title in the page table, and will
4255          * thus return false for interwiki links, special pages and the like.
4256          * If you want to know if a title can be meaningfully viewed, you should
4257          * probably call the isKnown() method instead.
4258          *
4259          * @param int $flags An optional bit field; may be Title::GAID_FOR_UPDATE to check
4260          *   from master/for update
4261          * @return bool
4262          */
4263         public function exists( $flags = 0 ) {
4264                 $exists = $this->getArticleID( $flags ) != 0;
4265                 Hooks::run( 'TitleExists', array( $this, &$exists ) );
4266                 return $exists;
4267         }
4268
4269         /**
4270          * Should links to this title be shown as potentially viewable (i.e. as
4271          * "bluelinks"), even if there's no record by this title in the page
4272          * table?
4273          *
4274          * This function is semi-deprecated for public use, as well as somewhat
4275          * misleadingly named.  You probably just want to call isKnown(), which
4276          * calls this function internally.
4277          *
4278          * (ISSUE: Most of these checks are cheap, but the file existence check
4279          * can potentially be quite expensive.  Including it here fixes a lot of
4280          * existing code, but we might want to add an optional parameter to skip
4281          * it and any other expensive checks.)
4282          *
4283          * @return bool
4284          */
4285         public function isAlwaysKnown() {
4286                 $isKnown = null;
4287
4288                 /**
4289                  * Allows overriding default behavior for determining if a page exists.
4290                  * If $isKnown is kept as null, regular checks happen. If it's
4291                  * a boolean, this value is returned by the isKnown method.
4292                  *
4293                  * @since 1.20
4294                  *
4295                  * @param Title $title
4296                  * @param bool|null $isKnown
4297                  */
4298                 Hooks::run( 'TitleIsAlwaysKnown', array( $this, &$isKnown ) );
4299
4300                 if ( !is_null( $isKnown ) ) {
4301                         return $isKnown;
4302                 }
4303
4304                 if ( $this->isExternal() ) {
4305                         return true;  // any interwiki link might be viewable, for all we know
4306                 }
4307
4308                 switch ( $this->mNamespace ) {
4309                         case NS_MEDIA:
4310                         case NS_FILE:
4311                                 // file exists, possibly in a foreign repo
4312                                 return (bool)wfFindFile( $this );
4313                         case NS_SPECIAL:
4314                                 // valid special page
4315                                 return SpecialPageFactory::exists( $this->getDBkey() );
4316                         case NS_MAIN:
4317                                 // selflink, possibly with fragment
4318                                 return $this->mDbkeyform == '';
4319                         case NS_MEDIAWIKI:
4320                                 // known system message
4321                                 return $this->hasSourceText() !== false;
4322                         default:
4323                                 return false;
4324                 }
4325         }
4326
4327         /**
4328          * Does this title refer to a page that can (or might) be meaningfully
4329          * viewed?  In particular, this function may be used to determine if
4330          * links to the title should be rendered as "bluelinks" (as opposed to
4331          * "redlinks" to non-existent pages).
4332          * Adding something else to this function will cause inconsistency
4333          * since LinkHolderArray calls isAlwaysKnown() and does its own
4334          * page existence check.
4335          *
4336          * @return bool
4337          */
4338         public function isKnown() {
4339                 return $this->isAlwaysKnown() || $this->exists();
4340         }
4341
4342         /**
4343          * Does this page have source text?
4344          *
4345          * @return bool
4346          */
4347         public function hasSourceText() {
4348                 if ( $this->exists() ) {
4349                         return true;
4350                 }
4351
4352                 if ( $this->mNamespace == NS_MEDIAWIKI ) {
4353                         // If the page doesn't exist but is a known system message, default
4354                         // message content will be displayed, same for language subpages-
4355                         // Use always content language to avoid loading hundreds of languages
4356                         // to get the link color.
4357                         global $wgContLang;
4358                         list( $name, ) = MessageCache::singleton()->figureMessage(
4359                                 $wgContLang->lcfirst( $this->getText() )
4360                         );
4361                         $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
4362                         return $message->exists();
4363                 }
4364
4365                 return false;
4366         }
4367
4368         /**
4369          * Get the default message text or false if the message doesn't exist
4370          *
4371          * @return string|bool
4372          */
4373         public function getDefaultMessageText() {
4374                 global $wgContLang;
4375
4376                 if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
4377                         return false;
4378                 }
4379
4380                 list( $name, $lang ) = MessageCache::singleton()->figureMessage(
4381                         $wgContLang->lcfirst( $this->getText() )
4382                 );
4383                 $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );
4384
4385                 if ( $message->exists() ) {
4386                         return $message->plain();
4387                 } else {
4388                         return false;
4389                 }
4390         }
4391
4392         /**
4393          * Updates page_touched for this page; called from LinksUpdate.php
4394          *
4395          * @param string $purgeTime [optional] TS_MW timestamp
4396          * @return bool True if the update succeeded
4397          */
4398         public function invalidateCache( $purgeTime = null ) {
4399                 if ( wfReadOnly() ) {
4400                         return false;
4401                 }
4402
4403                 if ( $this->mArticleID === 0 ) {
4404                         return true; // avoid gap locking if we know it's not there
4405                 }
4406
4407                 $method = __METHOD__;
4408                 $dbw = wfGetDB( DB_MASTER );
4409                 $conds = $this->pageCond();
4410                 $dbw->onTransactionIdle( function () use ( $dbw, $conds, $method, $purgeTime ) {
4411                         $dbTimestamp = $dbw->timestamp( $purgeTime ?: time() );
4412
4413                         $dbw->update(
4414                                 'page',
4415                                 array( 'page_touched' => $dbTimestamp ),
4416                                 $conds + array( 'page_touched < ' . $dbw->addQuotes( $dbTimestamp ) ),
4417                                 $method
4418                         );
4419                 } );
4420
4421                 return true;
4422         }
4423
4424         /**
4425          * Update page_touched timestamps and send CDN purge messages for
4426          * pages linking to this title. May be sent to the job queue depending
4427          * on the number of links. Typically called on create and delete.
4428          */
4429         public function touchLinks() {
4430                 DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'pagelinks' ) );
4431                 if ( $this->getNamespace() == NS_CATEGORY ) {
4432                         DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this, 'categorylinks' ) );
4433                 }
4434         }
4435
4436         /**
4437          * Get the last touched timestamp
4438          *
4439          * @param IDatabase $db Optional db
4440          * @return string Last-touched timestamp
4441          */
4442         public function getTouched( $db = null ) {
4443                 if ( $db === null ) {
4444                         $db = wfGetDB( DB_SLAVE );
4445                 }
4446                 $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
4447                 return $touched;
4448         }
4449
4450         /**
4451          * Get the timestamp when this page was updated since the user last saw it.
4452          *
4453          * @param User $user
4454          * @return string|null
4455          */
4456         public function getNotificationTimestamp( $user = null ) {
4457                 global $wgUser;
4458
4459                 // Assume current user if none given
4460                 if ( !$user ) {
4461                         $user = $wgUser;
4462                 }
4463                 // Check cache first
4464                 $uid = $user->getId();
4465                 if ( !$uid ) {
4466                         return false;
4467                 }
4468                 // avoid isset here, as it'll return false for null entries
4469                 if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
4470                         return $this->mNotificationTimestamp[$uid];
4471                 }
4472                 // Don't cache too much!
4473                 if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
4474                         $this->mNotificationTimestamp = array();
4475                 }
4476
4477                 $watchedItem = WatchedItem::fromUserTitle( $user, $this );
4478                 $this->mNotificationTimestamp[$uid] = $watchedItem->getNotificationTimestamp();
4479
4480                 return $this->mNotificationTimestamp[$uid];
4481         }
4482
4483         /**
4484          * Generate strings used for xml 'id' names in monobook tabs
4485          *
4486          * @param string $prepend Defaults to 'nstab-'
4487          * @return string XML 'id' name
4488          */
4489         public function getNamespaceKey( $prepend = 'nstab-' ) {
4490                 global $wgContLang;
4491                 // Gets the subject namespace if this title
4492                 $namespace = MWNamespace::getSubject( $this->getNamespace() );
4493                 // Checks if canonical namespace name exists for namespace
4494                 if ( MWNamespace::exists( $this->getNamespace() ) ) {
4495                         // Uses canonical namespace name
4496                         $namespaceKey = MWNamespace::getCanonicalName( $namespace );
4497                 } else {
4498                         // Uses text of namespace
4499                         $namespaceKey = $this->getSubjectNsText();
4500                 }
4501                 // Makes namespace key lowercase
4502                 $namespaceKey = $wgContLang->lc( $namespaceKey );
4503                 // Uses main
4504                 if ( $namespaceKey == '' ) {
4505                         $namespaceKey = 'main';
4506                 }
4507                 // Changes file to image for backwards compatibility
4508                 if ( $namespaceKey == 'file' ) {
4509                         $namespaceKey = 'image';
4510                 }
4511                 return $prepend . $namespaceKey;
4512         }
4513
4514         /**
4515          * Get all extant redirects to this Title
4516          *
4517          * @param int|null $ns Single namespace to consider; null to consider all namespaces
4518          * @return Title[] Array of Title redirects to this title
4519          */
4520         public function getRedirectsHere( $ns = null ) {
4521                 $redirs = array();
4522
4523                 $dbr = wfGetDB( DB_SLAVE );
4524                 $where = array(
4525                         'rd_namespace' => $this->getNamespace(),
4526                         'rd_title' => $this->getDBkey(),
4527                         'rd_from = page_id'
4528                 );
4529                 if ( $this->isExternal() ) {
4530                         $where['rd_interwiki'] = $this->getInterwiki();
4531                 } else {
4532                         $where[] = 'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL';
4533                 }
4534                 if ( !is_null( $ns ) ) {
4535                         $where['page_namespace'] = $ns;
4536                 }
4537
4538                 $res = $dbr->select(
4539                         array( 'redirect', 'page' ),
4540                         array( 'page_namespace', 'page_title' ),
4541                         $where,
4542                         __METHOD__
4543                 );
4544
4545                 foreach ( $res as $row ) {
4546                         $redirs[] = self::newFromRow( $row );
4547                 }
4548                 return $redirs;
4549         }
4550
4551         /**
4552          * Check if this Title is a valid redirect target
4553          *
4554          * @return bool
4555          */
4556         public function isValidRedirectTarget() {
4557                 global $wgInvalidRedirectTargets;
4558
4559                 if ( $this->isSpecialPage() ) {
4560                         // invalid redirect targets are stored in a global array, but explicitly disallow Userlogout here
4561                         if ( $this->isSpecial( 'Userlogout' ) ) {
4562                                 return false;
4563                         }
4564
4565                         foreach ( $wgInvalidRedirectTargets as $target ) {
4566                                 if ( $this->isSpecial( $target ) ) {
4567                                         return false;
4568                                 }
4569                         }
4570                 }
4571
4572                 return true;
4573         }
4574
4575         /**
4576          * Get a backlink cache object
4577          *
4578          * @return BacklinkCache
4579          */
4580         public function getBacklinkCache() {
4581                 return BacklinkCache::get( $this );
4582         }
4583
4584         /**
4585          * Whether the magic words __INDEX__ and __NOINDEX__ function for  this page.
4586          *
4587          * @return bool
4588          */
4589         public function canUseNoindex() {
4590                 global $wgContentNamespaces, $wgExemptFromUserRobotsControl;
4591
4592                 $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
4593                         ? $wgContentNamespaces
4594                         : $wgExemptFromUserRobotsControl;
4595
4596                 return !in_array( $this->mNamespace, $bannedNamespaces );
4597
4598         }
4599
4600         /**
4601          * Returns the raw sort key to be used for categories, with the specified
4602          * prefix.  This will be fed to Collation::getSortKey() to get a
4603          * binary sortkey that can be used for actual sorting.
4604          *
4605          * @param string $prefix The prefix to be used, specified using
4606          *   {{defaultsort:}} or like [[Category:Foo|prefix]].  Empty for no
4607          *   prefix.
4608          * @return string
4609          */
4610         public function getCategorySortkey( $prefix = '' ) {
4611                 $unprefixed = $this->getText();
4612
4613                 // Anything that uses this hook should only depend
4614                 // on the Title object passed in, and should probably
4615                 // tell the users to run updateCollations.php --force
4616                 // in order to re-sort existing category relations.
4617                 Hooks::run( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
4618                 if ( $prefix !== '' ) {
4619                         # Separate with a line feed, so the unprefixed part is only used as
4620                         # a tiebreaker when two pages have the exact same prefix.
4621                         # In UCA, tab is the only character that can sort above LF
4622                         # so we strip both of them from the original prefix.
4623                         $prefix = strtr( $prefix, "\n\t", '  ' );
4624                         return "$prefix\n$unprefixed";
4625                 }
4626                 return $unprefixed;
4627         }
4628
4629         /**
4630          * Get the language in which the content of this page is written in
4631          * wikitext. Defaults to $wgContLang, but in certain cases it can be
4632          * e.g. $wgLang (such as special pages, which are in the user language).
4633          *
4634          * @since 1.18
4635          * @return Language
4636          */
4637         public function getPageLanguage() {
4638                 global $wgLang, $wgLanguageCode;
4639                 if ( $this->isSpecialPage() ) {
4640                         // special pages are in the user language
4641                         return $wgLang;
4642                 }
4643
4644                 // Checking if DB language is set
4645                 if ( $this->mDbPageLanguage ) {
4646                         return wfGetLangObj( $this->mDbPageLanguage );
4647                 }
4648
4649                 if ( !$this->mPageLanguage || $this->mPageLanguage[1] !== $wgLanguageCode ) {
4650                         // Note that this may depend on user settings, so the cache should
4651                         // be only per-request.
4652                         // NOTE: ContentHandler::getPageLanguage() may need to load the
4653                         // content to determine the page language!
4654                         // Checking $wgLanguageCode hasn't changed for the benefit of unit
4655                         // tests.
4656                         $contentHandler = ContentHandler::getForTitle( $this );
4657                         $langObj = wfGetLangObj( $contentHandler->getPageLanguage( $this ) );
4658                         $this->mPageLanguage = array( $langObj->getCode(), $wgLanguageCode );
4659                 } else {
4660                         $langObj = wfGetLangObj( $this->mPageLanguage[0] );
4661                 }
4662
4663                 return $langObj;
4664         }
4665
4666         /**
4667          * Get the language in which the content of this page is written when
4668          * viewed by user. Defaults to $wgContLang, but in certain cases it can be
4669          * e.g. $wgLang (such as special pages, which are in the user language).
4670          *
4671          * @since 1.20
4672          * @return Language
4673          */
4674         public function getPageViewLanguage() {
4675                 global $wgLang;
4676
4677                 if ( $this->isSpecialPage() ) {
4678                         // If the user chooses a variant, the content is actually
4679                         // in a language whose code is the variant code.
4680                         $variant = $wgLang->getPreferredVariant();
4681                         if ( $wgLang->getCode() !== $variant ) {
4682                                 return Language::factory( $variant );
4683                         }
4684
4685                         return $wgLang;
4686                 }
4687
4688                 // @note Can't be cached persistently, depends on user settings.
4689                 // @note ContentHandler::getPageViewLanguage() may need to load the
4690                 //   content to determine the page language!
4691                 $contentHandler = ContentHandler::getForTitle( $this );
4692                 $pageLang = $contentHandler->getPageViewLanguage( $this );
4693                 return $pageLang;
4694         }
4695
4696         /**
4697          * Get a list of rendered edit notices for this page.
4698          *
4699          * Array is keyed by the original message key, and values are rendered using parseAsBlock, so
4700          * they will already be wrapped in paragraphs.
4701          *
4702          * @since 1.21
4703          * @param int $oldid Revision ID that's being edited
4704          * @return array
4705          */
4706         public function getEditNotices( $oldid = 0 ) {
4707                 $notices = array();
4708
4709                 // Optional notice for the entire namespace
4710                 $editnotice_ns = 'editnotice-' . $this->getNamespace();
4711                 $msg = wfMessage( $editnotice_ns );
4712                 if ( $msg->exists() ) {
4713                         $html = $msg->parseAsBlock();
4714                         // Edit notices may have complex logic, but output nothing (T91715)
4715                         if ( trim( $html ) !== '' ) {
4716                                 $notices[$editnotice_ns] = Html::rawElement(
4717                                         'div',
4718                                         array( 'class' => array(
4719                                                 'mw-editnotice',
4720                                                 'mw-editnotice-namespace',
4721                                                 Sanitizer::escapeClass( "mw-$editnotice_ns" )
4722                                         ) ),
4723                                         $html
4724                                 );
4725                         }
4726                 }
4727
4728                 if ( MWNamespace::hasSubpages( $this->getNamespace() ) ) {
4729                         // Optional notice for page itself and any parent page
4730                         $parts = explode( '/', $this->getDBkey() );
4731                         $editnotice_base = $editnotice_ns;
4732                         while ( count( $parts ) > 0 ) {
4733                                 $editnotice_base .= '-' . array_shift( $parts );
4734                                 $msg = wfMessage( $editnotice_base );
4735                                 if ( $msg->exists() ) {
4736                                         $html = $msg->parseAsBlock();
4737                                         if ( trim( $html ) !== '' ) {
4738                                                 $notices[$editnotice_base] = Html::rawElement(
4739                                                         'div',
4740                                                         array( 'class' => array(
4741                                                                 'mw-editnotice',
4742                                                                 'mw-editnotice-base',
4743                                                                 Sanitizer::escapeClass( "mw-$editnotice_base" )
4744                                                         ) ),
4745                                                         $html
4746                                                 );
4747                                         }
4748                                 }
4749                         }
4750                 } else {
4751                         // Even if there are no subpages in namespace, we still don't want "/" in MediaWiki message keys
4752                         $editnoticeText = $editnotice_ns . '-' . strtr( $this->getDBkey(), '/', '-' );
4753                         $msg = wfMessage( $editnoticeText );
4754                         if ( $msg->exists() ) {
4755                                 $html = $msg->parseAsBlock();
4756                                 if ( trim( $html ) !== '' ) {
4757                                         $notices[$editnoticeText] = Html::rawElement(
4758                                                 'div',
4759                                                 array( 'class' => array(
4760                                                         'mw-editnotice',
4761                                                         'mw-editnotice-page',
4762                                                         Sanitizer::escapeClass( "mw-$editnoticeText" )
4763                                                 ) ),
4764                                                 $html
4765                                         );
4766                                 }
4767                         }
4768                 }
4769
4770                 Hooks::run( 'TitleGetEditNotices', array( $this, $oldid, &$notices ) );
4771                 return $notices;
4772         }
4773
4774         /**
4775          * @return array
4776          */
4777         public function __sleep() {
4778                 return array(
4779                         'mNamespace',
4780                         'mDbkeyform',
4781                         'mFragment',
4782                         'mInterwiki',
4783                         'mLocalInterwiki',
4784                         'mUserCaseDBKey',
4785                         'mDefaultNamespace',
4786                 );
4787         }
4788
4789         public function __wakeup() {
4790                 $this->mArticleID = ( $this->mNamespace >= 0 ) ? -1 : 0;
4791                 $this->mUrlform = wfUrlencode( $this->mDbkeyform );
4792                 $this->mTextform = strtr( $this->mDbkeyform, '_', ' ' );
4793         }
4794
4795 }