Title.php

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<?php
class Title {
        // @{
        static private $titleCache = array();
        // @}

        const CACHE_MAX = 1000;

        const GAID_FOR_UPDATE = 1;

        // @{

        var $mTextform = '';              // /< Text form (spaces not underscores) of the main part
        var $mUrlform = '';               // /< URL-encoded form of the main part
        var $mDbkeyform = '';             // /< Main part with underscores
        var $mUserCaseDBKey;              // /< DB key with the initial letter in the case specified by the user
        var $mNamespace = NS_MAIN;        // /< Namespace index, i.e. one of the NS_xxxx constants
        var $mInterwiki = '';             // /< Interwiki prefix (or null string)
        var $mFragment;                   // /< Title fragment (i.e. the bit after the #)
        var $mArticleID = -1;             // /< Article ID, fetched from the link cache on demand
        var $mLatestID = false;           // /< ID of most recent revision
        private $mEstimateRevisions;      // /< Estimated number of revisions; null of not loaded
        var $mRestrictions = array();     // /< Array of groups allowed to edit this article
        var $mOldRestrictions = false;
        var $mCascadeRestriction;         
        var $mCascadingRestrictions;      // Caching the results of getCascadeProtectionSources
        var $mRestrictionsExpiry = array(); 
        var $mHasCascadingRestrictions;   
        var $mCascadeSources;             
        var $mRestrictionsLoaded = false; 
        var $mPrefixedText;               
        var $mTitleProtection;            
        # Don't change the following default, NS_MAIN is hardcoded in several
        # places.  See bug 696.
        var $mDefaultNamespace = NS_MAIN; // /< Namespace index when there is no namespace
                                                                          # Zero except in {{transclusion}} tags
        var $mWatched = null;             // /< Is $wgUser watching this page? null if unfilled, accessed through userIsWatching()
        var $mLength = -1;                // /< The page length, 0 for special pages
        var $mRedirect = null;            // /< Is the article at this title a redirect?
        var $mNotificationTimestamp = array(); // /< Associative array of user ID -> timestamp/false
        var $mBacklinkCache = null;       // /< Cache of links to this title
        // @}


        /*protected*/ function __construct() { }

        public static function newFromDBkey( $key ) {
                $t = new Title();
                $t->mDbkeyform = $key;
                if ( $t->secureAndSplit() ) {
                        return $t;
                } else {
                        return null;
                }
        }

        public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
                if ( is_object( $text ) ) {
                        throw new MWException( 'Title::newFromText given an object' );
                }

                if ( $defaultNamespace == NS_MAIN && isset( Title::$titleCache[$text] ) ) {
                        return Title::$titleCache[$text];
                }

                # Convert things like &eacute; &#257; or &#x3017; into normalized (bug 14952) text
                $filteredText = Sanitizer::decodeCharReferencesAndNormalize( $text );

                $t = new Title();
                $t->mDbkeyform = str_replace( ' ', '_', $filteredText );
                $t->mDefaultNamespace = $defaultNamespace;

                static $cachedcount = 0 ;
                if ( $t->secureAndSplit() ) {
                        if ( $defaultNamespace == NS_MAIN ) {
                                if ( $cachedcount >= self::CACHE_MAX ) {
                                        # Avoid memory leaks on mass operations...
                                        Title::$titleCache = array();
                                        $cachedcount = 0;
                                }
                                $cachedcount++;
                                Title::$titleCache[$text] =& $t;
                        }
                        return $t;
                } else {
                        $ret = null;
                        return $ret;
                }
        }

        public static function newFromURL( $url ) {
                global $wgLegalTitleChars;
                $t = new Title();

                # For compatibility with old buggy URLs. "+" is usually not valid in titles,
                # but some URLs used it as a space replacement and they still come
                # from some external search tools.
                if ( strpos( $wgLegalTitleChars, '+' ) === false ) {
                        $url = str_replace( '+', ' ', $url );
                }

                $t->mDbkeyform = str_replace( ' ', '_', $url );
                if ( $t->secureAndSplit() ) {
                        return $t;
                } else {
                        return null;
                }
        }

        public static function newFromID( $id, $flags = 0 ) {
                $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
                $row = $db->selectRow( 'page', '*', array( 'page_id' => $id ), __METHOD__ );
                if ( $row !== false ) {
                        $title = Title::newFromRow( $row );
                } else {
                        $title = null;
                }
                return $title;
        }

        public static function newFromIDs( $ids ) {
                if ( !count( $ids ) ) {
                        return array();
                }
                $dbr = wfGetDB( DB_SLAVE );

                $res = $dbr->select(
                        'page',
                        array(
                                'page_namespace', 'page_title', 'page_id',
                                'page_len', 'page_is_redirect', 'page_latest',
                        ),
                        array( 'page_id' => $ids ),
                        __METHOD__
                );

                $titles = array();
                foreach ( $res as $row ) {
                        $titles[] = Title::newFromRow( $row );
                }
                return $titles;
        }

        public static function newFromRow( $row ) {
                $t = self::makeTitle( $row->page_namespace, $row->page_title );
                $t->loadFromRow( $row );
                return $t;
        }

        public function loadFromRow( $row ) {
                if ( $row ) { // page found
                        if ( isset( $row->page_id ) )
                                $this->mArticleID = (int)$row->page_id;
                        if ( isset( $row->page_len ) )
                                $this->mLength = (int)$row->page_len;
                        if ( isset( $row->page_is_redirect ) )
                                $this->mRedirect = (bool)$row->page_is_redirect;
                        if ( isset( $row->page_latest ) )
                                $this->mLatestID = (int)$row->page_latest;
                } else { // page not found
                        $this->mArticleID = 0;
                        $this->mLength = 0;
                        $this->mRedirect = false;
                        $this->mLatestID = 0;
                }
        }

        public static function &makeTitle( $ns, $title, $fragment = '', $interwiki = '' ) {
                $t = new Title();
                $t->mInterwiki = $interwiki;
                $t->mFragment = $fragment;
                $t->mNamespace = $ns = intval( $ns );
                $t->mDbkeyform = str_replace( ' ', '_', $title );
                $t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
                $t->mUrlform = wfUrlencode( $t->mDbkeyform );
                $t->mTextform = str_replace( '_', ' ', $title );
                return $t;
        }

        public static function makeTitleSafe( $ns, $title, $fragment = '', $interwiki = '' ) {
                $t = new Title();
                $t->mDbkeyform = Title::makeName( $ns, $title, $fragment, $interwiki );
                if ( $t->secureAndSplit() ) {
                        return $t;
                } else {
                        return null;
                }
        }

        public static function newMainPage() {
                $title = Title::newFromText( wfMsgForContent( 'mainpage' ) );
                // Don't give fatal errors if the message is broken
                if ( !$title ) {
                        $title = Title::newFromText( 'Main Page' );
                }
                return $title;
        }

        public static function newFromRedirect( $text ) {
                return self::newFromRedirectInternal( $text );
        }

        public static function newFromRedirectRecurse( $text ) {
                $titles = self::newFromRedirectArray( $text );
                return $titles ? array_pop( $titles ) : null;
        }

        public static function newFromRedirectArray( $text ) {
                global $wgMaxRedirects;
                $title = self::newFromRedirectInternal( $text );
                if ( is_null( $title ) ) {
                        return null;
                }
                // recursive check to follow double redirects
                $recurse = $wgMaxRedirects;
                $titles = array( $title );
                while ( --$recurse > 0 ) {
                        if ( $title->isRedirect() ) {
                                $page = WikiPage::factory( $title );
                                $newtitle = $page->getRedirectTarget();
                        } else {
                                break;
                        }
                        // Redirects to some special pages are not permitted
                        if ( $newtitle instanceOf Title && $newtitle->isValidRedirectTarget() ) {
                                // the new title passes the checks, so make that our current title so that further recursion can be checked
                                $title = $newtitle;
                                $titles[] = $newtitle;
                        } else {
                                break;
                        }
                }
                return $titles;
        }

        protected static function newFromRedirectInternal( $text ) {
                global $wgMaxRedirects;
                if ( $wgMaxRedirects < 1 ) {
                        //redirects are disabled, so quit early
                        return null;
                }
                $redir = MagicWord::get( 'redirect' );
                $text = trim( $text );
                if ( $redir->matchStartAndRemove( $text ) ) {
                        // Extract the first link and see if it's usable
                        // Ensure that it really does come directly after #REDIRECT
                        // Some older redirects included a colon, so don't freak about that!
                        $m = array();
                        if ( preg_match( '!^\s*:?\s*\[{2}(.*?)(?:\|.*?)?\]{2}!', $text, $m ) ) {
                                // Strip preceding colon used to "escape" categories, etc.
                                // and URL-decode links
                                if ( strpos( $m[1], '%' ) !== false ) {
                                        // Match behavior of inline link parsing here;
                                        $m[1] = rawurldecode( ltrim( $m[1], ':' ) );
                                }
                                $title = Title::newFromText( $m[1] );
                                // If the title is a redirect to bad special pages or is invalid, return null
                                if ( !$title instanceof Title || !$title->isValidRedirectTarget() ) {
                                        return null;
                                }
                                return $title;
                        }
                }
                return null;
        }

        public static function nameOf( $id ) {
                $dbr = wfGetDB( DB_SLAVE );

                $s = $dbr->selectRow(
                        'page',
                        array( 'page_namespace', 'page_title' ),
                        array( 'page_id' => $id ),
                        __METHOD__
                );
                if ( $s === false ) {
                        return null;
                }

                $n = self::makeName( $s->page_namespace, $s->page_title );
                return $n;
        }

        public static function legalChars() {
                global $wgLegalTitleChars;
                return $wgLegalTitleChars;
        }

        static function getTitleInvalidRegex() {
                static $rxTc = false;
                if ( !$rxTc ) {
                        # Matching titles will be held as illegal.
                        $rxTc = '/' .
                                # Any character not allowed is forbidden...
                                '[^' . self::legalChars() . ']' .
                                # URL percent encoding sequences interfere with the ability
                                # to round-trip titles -- you can't link to them consistently.
                                '|%[0-9A-Fa-f]{2}' .
                                # XML/HTML character references produce similar issues.
                                '|&[A-Za-z0-9\x80-\xff]+;' .
                                '|&#[0-9]+;' .
                                '|&#x[0-9A-Fa-f]+;' .
                                '/S';
                }

                return $rxTc;
        }

        public static function indexTitle( $ns, $title ) {
                global $wgContLang;

                $lc = SearchEngine::legalSearchChars() . '&#;';
                $t = $wgContLang->normalizeForSearch( $title );
                $t = preg_replace( "/[^{$lc}]+/", ' ', $t );
                $t = $wgContLang->lc( $t );

                # Handle 's, s'
                $t = preg_replace( "/([{$lc}]+)'s( |$)/", "\\1 \\1's ", $t );
                $t = preg_replace( "/([{$lc}]+)s'( |$)/", "\\1s ", $t );

                $t = preg_replace( "/\\s+/", ' ', $t );

                if ( $ns == NS_FILE ) {
                        $t = preg_replace( "/ (png|gif|jpg|jpeg|ogg)$/", "", $t );
                }
                return trim( $t );
        }

        public static function makeName( $ns, $title, $fragment = '', $interwiki = '' ) {
                global $wgContLang;

                $namespace = $wgContLang->getNsText( $ns );
                $name = $namespace == '' ? $title : "$namespace:$title";
                if ( strval( $interwiki ) != '' ) {
                        $name = "$interwiki:$name";
                }
                if ( strval( $fragment ) != '' ) {
                        $name .= '#' . $fragment;
                }
                return $name;
        }

        static function escapeFragmentForURL( $fragment ) {
                # Note that we don't urlencode the fragment.  urlencoded Unicode
                # fragments appear not to work in IE (at least up to 7) or in at least
                # one version of Opera 9.x.  The W3C validator, for one, doesn't seem
                # to care if they aren't encoded.
                return Sanitizer::escapeId( $fragment, 'noninitial' );
        }

        public static function compare( $a, $b ) {
                if ( $a->getNamespace() == $b->getNamespace() ) {
                        return strcmp( $a->getText(), $b->getText() );
                } else {
                        return $a->getNamespace() - $b->getNamespace();
                }
        }

        public function isLocal() {
                if ( $this->mInterwiki != '' ) {
                        return Interwiki::fetch( $this->mInterwiki )->isLocal();
                } else {
                        return true;
                }
        }

        public function isExternal() {
                return ( $this->mInterwiki != '' );
        }

        public function getInterwiki() {
                return $this->mInterwiki;
        }

        public function isTrans() {
                if ( $this->mInterwiki == '' ) {
                        return false;
                }

                return Interwiki::fetch( $this->mInterwiki )->isTranscludable();
        }

        public function getTransWikiID() {
                if ( $this->mInterwiki == '' ) {
                        return false;
                }

                return Interwiki::fetch( $this->mInterwiki )->getWikiID();
        }

        public function getText() {
                return $this->mTextform;
        }

        public function getPartialURL() {
                return $this->mUrlform;
        }

        public function getDBkey() {
                return $this->mDbkeyform;
        }

        function getUserCaseDBKey() {
                return $this->mUserCaseDBKey;
        }

        public function getNamespace() {
                return $this->mNamespace;
        }

        public function getNsText() {
                global $wgContLang;

                if ( $this->mInterwiki != '' ) {
                        // This probably shouldn't even happen. ohh man, oh yuck.
                        // But for interwiki transclusion it sometimes does.
                        // Shit. Shit shit shit.
                        //
                        // Use the canonical namespaces if possible to try to
                        // resolve a foreign namespace.
                        if ( MWNamespace::exists( $this->mNamespace ) ) {
                                return MWNamespace::getCanonicalName( $this->mNamespace );
                        }
                }

                // Strip off subpages
                $pagename = $this->getText();
                if ( strpos( $pagename, '/' ) !== false ) {
                        list( $username , ) = explode( '/', $pagename, 2 );
                } else {
                        $username = $pagename;
                }

                if ( $wgContLang->needsGenderDistinction() &&
                                MWNamespace::hasGenderDistinction( $this->mNamespace ) ) {
                        $gender = GenderCache::singleton()->getGenderOf( $username, __METHOD__ );
                        return $wgContLang->getGenderNsText( $this->mNamespace, $gender );
                }

                return $wgContLang->getNsText( $this->mNamespace );
        }

        public function getSubjectNsText() {
                global $wgContLang;
                return $wgContLang->getNsText( MWNamespace::getSubject( $this->mNamespace ) );
        }

        public function getTalkNsText() {
                global $wgContLang;
                return( $wgContLang->getNsText( MWNamespace::getTalk( $this->mNamespace ) ) );
        }

        public function canTalk() {
                return( MWNamespace::canTalk( $this->mNamespace ) );
        }

        public function canExist() {
                return $this->mNamespace >= NS_MAIN;
        }

        public function isWatchable() {
                return !$this->isExternal() && MWNamespace::isWatchable( $this->getNamespace() );
        }

        public function isSpecialPage() {
                return $this->getNamespace() == NS_SPECIAL;
        }

        public function isSpecial( $name ) {
                if ( $this->isSpecialPage() ) {
                        list( $thisName, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $this->getDBkey() );
                        if ( $name == $thisName ) {
                                return true;
                        }
                }
                return false;
        }

        public function fixSpecialName() {
                if ( $this->isSpecialPage() ) {
                        list( $canonicalName, $par ) = SpecialPageFactory::resolveAlias( $this->mDbkeyform );
                        if ( $canonicalName ) {
                                $localName = SpecialPageFactory::getLocalNameFor( $canonicalName, $par );
                                if ( $localName != $this->mDbkeyform ) {
                                        return Title::makeTitle( NS_SPECIAL, $localName );
                                }
                        }
                }
                return $this;
        }

        public function inNamespace( $ns ) {
                return MWNamespace::equals( $this->getNamespace(), $ns );
        }

        public function inNamespaces( /* ... */ ) {
                $namespaces = func_get_args();
                if ( count( $namespaces ) > 0 && is_array( $namespaces[0] ) ) {
                        $namespaces = $namespaces[0];
                }

                foreach ( $namespaces as $ns ) {
                        if ( $this->inNamespace( $ns ) ) {
                                return true;
                        }
                }

                return false;
        }

        public function hasSubjectNamespace( $ns ) {
                return MWNamespace::subjectEquals( $this->getNamespace(), $ns );
        }

        public function isContentPage() {
                return MWNamespace::isContent( $this->getNamespace() );
        }

        public function isMovable() {
                if ( !MWNamespace::isMovable( $this->getNamespace() ) || $this->getInterwiki() != '' ) {
                        // Interwiki title or immovable namespace. Hooks don't get to override here
                        return false;
                }

                $result = true;
                wfRunHooks( 'TitleIsMovable', array( $this, &$result ) );
                return $result;
        }

        public function isMainPage() {
                return $this->equals( Title::newMainPage() );
        }

        public function isSubpage() {
                return MWNamespace::hasSubpages( $this->mNamespace )
                        ? strpos( $this->getText(), '/' ) !== false
                        : false;
        }

        public function isConversionTable() {
                return $this->getNamespace() == NS_MEDIAWIKI &&
                        strpos( $this->getText(), 'Conversiontable' ) !== false;
        }

        public function isWikitextPage() {
                $retval = !$this->isCssOrJsPage() && !$this->isCssJsSubpage();
                wfRunHooks( 'TitleIsWikitextPage', array( $this, &$retval ) );
                return $retval;
        }

        public function isCssOrJsPage() {
                $retval = $this->mNamespace == NS_MEDIAWIKI
                        && preg_match( '!\.(?:css|js)$!u', $this->mTextform ) > 0;
                wfRunHooks( 'TitleIsCssOrJsPage', array( $this, &$retval ) );
                return $retval;
        }

        public function isCssJsSubpage() {
                return ( NS_USER == $this->mNamespace and preg_match( "/\\/.*\\.(?:css|js)$/", $this->mTextform ) );
        }

        public function getSkinFromCssJsSubpage() {
                $subpage = explode( '/', $this->mTextform );
                $subpage = $subpage[ count( $subpage ) - 1 ];
                $lastdot = strrpos( $subpage, '.' );
                if ( $lastdot === false )
                        return $subpage; # Never happens: only called for names ending in '.css' or '.js'
                return substr( $subpage, 0, $lastdot );
        }

        public function isCssSubpage() {
                return ( NS_USER == $this->mNamespace && preg_match( "/\\/.*\\.css$/", $this->mTextform ) );
        }

        public function isJsSubpage() {
                return ( NS_USER == $this->mNamespace && preg_match( "/\\/.*\\.js$/", $this->mTextform ) );
        }

        public function isTalkPage() {
                return MWNamespace::isTalk( $this->getNamespace() );
        }

        public function getTalkPage() {
                return Title::makeTitle( MWNamespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
        }

        public function getSubjectPage() {
                // Is this the same title?
                $subjectNS = MWNamespace::getSubject( $this->getNamespace() );
                if ( $this->getNamespace() == $subjectNS ) {
                        return $this;
                }
                return Title::makeTitle( $subjectNS, $this->getDBkey() );
        }

        public function getDefaultNamespace() {
                return $this->mDefaultNamespace;
        }

        public function getIndexTitle() {
                return Title::indexTitle( $this->mNamespace, $this->mTextform );
        }

        public function getFragment() {
                return $this->mFragment;
        }

        public function getFragmentForURL() {
                if ( $this->mFragment == '' ) {
                        return '';
                } else {
                        return '#' . Title::escapeFragmentForURL( $this->mFragment );
                }
        }

        public function setFragment( $fragment ) {
                $this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
        }

        private function prefix( $name ) {
                $p = '';
                if ( $this->mInterwiki != '' ) {
                        $p = $this->mInterwiki . ':';
                }

                if ( 0 != $this->mNamespace ) {
                        $p .= $this->getNsText() . ':';
                }
                return $p . $name;
        }

        public function getPrefixedDBkey() {
                $s = $this->prefix( $this->mDbkeyform );
                $s = str_replace( ' ', '_', $s );
                return $s;
        }

        public function getPrefixedText() {
                // @todo FIXME: Bad usage of empty() ?
                if ( empty( $this->mPrefixedText ) ) {
                        $s = $this->prefix( $this->mTextform );
                        $s = str_replace( '_', ' ', $s );
                        $this->mPrefixedText = $s;
                }
                return $this->mPrefixedText;
        }

        public function __toString() {
                return $this->getPrefixedText();
        }

        public function getFullText() {
                $text = $this->getPrefixedText();
                if ( $this->mFragment != '' ) {
                        $text .= '#' . $this->mFragment;
                }
                return $text;
        }

        public function getBaseText() {
                if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
                        return $this->getText();
                }

                $parts = explode( '/', $this->getText() );
                # Don't discard the real title if there's no subpage involved
                if ( count( $parts ) > 1 ) {
                        unset( $parts[count( $parts ) - 1] );
                }
                return implode( '/', $parts );
        }

        public function getSubpageText() {
                if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
                        return( $this->mTextform );
                }
                $parts = explode( '/', $this->mTextform );
                return( $parts[count( $parts ) - 1] );
        }

        public function getEscapedText() {
                wfDeprecated( __METHOD__, '1.19' );
                return htmlspecialchars( $this->getPrefixedText() );
        }

        public function getSubpageUrlForm() {
                $text = $this->getSubpageText();
                $text = wfUrlencode( str_replace( ' ', '_', $text ) );
                return( $text );
        }

        public function getPrefixedURL() {
                $s = $this->prefix( $this->mDbkeyform );
                $s = wfUrlencode( str_replace( ' ', '_', $s ) );
                return $s;
        }

        private static function fixUrlQueryArgs( $query, $query2 = false ) {
                if( $query2 !== false ) {
                        wfDeprecated( "Title::get{Canonical,Full,Link,Local} method called with a second parameter is deprecated. Add your parameter to an array passed as the first parameter.", "1.19" );
                }
                if ( is_array( $query ) ) {
                        $query = wfArrayToCGI( $query );
                }
                if ( $query2 ) {
                        if ( is_string( $query2 ) ) {
                                // $query2 is a string, we will consider this to be
                                // a deprecated $variant argument and add it to the query
                                $query2 = wfArrayToCGI( array( 'variant' => $query2 ) );
                        } else {
                                $query2 = wfArrayToCGI( $query2 );
                        }
                        // If we have $query content add a & to it first
                        if ( $query ) {
                                $query .= '&';
                        }
                        // Now append the queries together
                        $query .= $query2;
                }
                return $query;
        }

        public function getFullURL( $query = '', $query2 = false ) {
                $query = self::fixUrlQueryArgs( $query, $query2 );

                # Hand off all the decisions on urls to getLocalURL
                $url = $this->getLocalURL( $query );

                # Expand the url to make it a full url. Note that getLocalURL has the
                # potential to output full urls for a variety of reasons, so we use
                # wfExpandUrl instead of simply prepending $wgServer
                $url = wfExpandUrl( $url, PROTO_RELATIVE );

                # Finally, add the fragment.
                $url .= $this->getFragmentForURL();

                wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
                return $url;
        }

        public function getLocalURL( $query = '', $query2 = false ) {
                global $wgArticlePath, $wgScript, $wgServer, $wgRequest;

                $query = self::fixUrlQueryArgs( $query, $query2 );

                $interwiki = Interwiki::fetch( $this->mInterwiki );
                if ( $interwiki ) {
                        $namespace = $this->getNsText();
                        if ( $namespace != '' ) {
                                # Can this actually happen? Interwikis shouldn't be parsed.
                                # Yes! It can in interwiki transclusion. But... it probably shouldn't.
                                $namespace .= ':';
                        }
                        $url = $interwiki->getURL( $namespace . $this->getDBkey() );
                        $url = wfAppendQuery( $url, $query );
                } else {
                        $dbkey = wfUrlencode( $this->getPrefixedDBkey() );
                        if ( $query == '' ) {
                                $url = str_replace( '$1', $dbkey, $wgArticlePath );
                                wfRunHooks( 'GetLocalURL::Article', array( &$this, &$url ) );
                        } else {
                                global $wgVariantArticlePath, $wgActionPaths;
                                $url = false;
                                $matches = array();

                                if ( !empty( $wgActionPaths ) &&
                                        preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches ) )
                                {
                                        $action = urldecode( $matches[2] );
                                        if ( isset( $wgActionPaths[$action] ) ) {
                                                $query = $matches[1];
                                                if ( isset( $matches[4] ) ) {
                                                        $query .= $matches[4];
                                                }
                                                $url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
                                                if ( $query != '' ) {
                                                        $url = wfAppendQuery( $url, $query );
                                                }
                                        }
                                }

                                if ( $url === false &&
                                        $wgVariantArticlePath &&
                                        $this->getPageLanguage()->hasVariants() &&
                                        preg_match( '/^variant=([^&]*)$/', $query, $matches ) )
                                {
                                        $variant = urldecode( $matches[1] );
                                        if ( $this->getPageLanguage()->hasVariant( $variant ) ) {
                                                // Only do the variant replacement if the given variant is a valid
                                                // variant for the page's language.
                                                $url = str_replace( '$2', urlencode( $variant ), $wgVariantArticlePath );
                                                $url = str_replace( '$1', $dbkey, $url );
                                        }
                                }

                                if ( $url === false ) {
                                        if ( $query == '-' ) {
                                                $query = '';
                                        }
                                        $url = "{$wgScript}?title={$dbkey}&{$query}";
                                }
                        }

                        wfRunHooks( 'GetLocalURL::Internal', array( &$this, &$url, $query ) );

                        // @todo FIXME: This causes breakage in various places when we
                        // actually expected a local URL and end up with dupe prefixes.
                        if ( $wgRequest->getVal( 'action' ) == 'render' ) {
                                $url = $wgServer . $url;
                        }
                }
                wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
                return $url;
        }

        public function getLinkURL( $query = '', $query2 = false ) {
                wfProfileIn( __METHOD__ );
                if ( $this->isExternal() ) {
                        $ret = $this->getFullURL( $query, $query2 );
                } elseif ( $this->getPrefixedText() === '' && $this->getFragment() !== '' ) {
                        $ret = $this->getFragmentForURL();
                } else {
                        $ret = $this->getLocalURL( $query, $query2 ) . $this->getFragmentForURL();
                }
                wfProfileOut( __METHOD__ );
                return $ret;
        }

        public function escapeLocalURL( $query = '', $query2 = false ) {
                wfDeprecated( __METHOD__, '1.19' );
                return htmlspecialchars( $this->getLocalURL( $query, $query2 ) );
        }

        public function escapeFullURL( $query = '', $query2 = false ) {
                wfDeprecated( __METHOD__, '1.19' );
                return htmlspecialchars( $this->getFullURL( $query, $query2 ) );
        }

        public function getInternalURL( $query = '', $query2 = false ) {
                global $wgInternalServer, $wgServer;
                $query = self::fixUrlQueryArgs( $query, $query2 );
                $server = $wgInternalServer !== false ? $wgInternalServer : $wgServer;
                $url = wfExpandUrl( $server . $this->getLocalURL( $query ), PROTO_HTTP );
                wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
                return $url;
        }

        public function getCanonicalURL( $query = '', $query2 = false ) {
                $query = self::fixUrlQueryArgs( $query, $query2 );
                $url = wfExpandUrl( $this->getLocalURL( $query ) . $this->getFragmentForURL(), PROTO_CANONICAL );
                wfRunHooks( 'GetCanonicalURL', array( &$this, &$url, $query ) );
                return $url;
        }

        public function escapeCanonicalURL( $query = '', $query2 = false ) {
                wfDeprecated( __METHOD__, '1.19' );
                return htmlspecialchars( $this->getCanonicalURL( $query, $query2 ) );
        }

        public function getEditURL() {
                if ( $this->mInterwiki != '' ) {
                        return '';
                }
                $s = $this->getLocalURL( 'action=edit' );

                return $s;
        }

        public function userIsWatching() {
                global $wgUser;

                if ( is_null( $this->mWatched ) ) {
                        if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn() ) {
                                $this->mWatched = false;
                        } else {
                                $this->mWatched = $wgUser->isWatched( $this );
                        }
                }
                return $this->mWatched;
        }

        public function userCanRead() {
                wfDeprecated( __METHOD__, '1.19' );
                return $this->userCan( 'read' );
        }

        public function quickUserCan( $action, $user = null ) {
                return $this->userCan( $action, $user, false );
        }

        public function userCan( $action, $user = null, $doExpensiveQueries = true ) {
                if ( !$user instanceof User ) {
                        global $wgUser;
                        $user = $wgUser;
                }
                return !count( $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries, true ) );
        }

        public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true, $ignoreErrors = array() ) {
                $errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );

                // Remove the errors being ignored.
                foreach ( $errors as $index => $error ) {
                        $error_key = is_array( $error ) ? $error[0] : $error;

                        if ( in_array( $error_key, $ignoreErrors ) ) {
                                unset( $errors[$index] );
                        }
                }

                return $errors;
        }

        private function checkQuickPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
                if ( $action == 'create' ) {
                        if ( ( $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
                                 ( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) ) ) {
                                $errors[] = $user->isAnon() ? array( 'nocreatetext' ) : array( 'nocreate-loggedin' );
                        }
                } elseif ( $action == 'move' ) {
                        if ( !$user->isAllowed( 'move-rootuserpages' )
                                        && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
                                // Show user page-specific message only if the user can move other pages
                                $errors[] = array( 'cant-move-user-page' );
                        }

                        // Check if user is allowed to move files if it's a file
                        if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 'movefile' ) ) {
                                $errors[] = array( 'movenotallowedfile' );
                        }

                        if ( !$user->isAllowed( 'move' ) ) {
                                // User can't move anything
                                global $wgGroupPermissions;
                                $userCanMove = false;
                                if ( isset( $wgGroupPermissions['user']['move'] ) ) {
                                        $userCanMove = $wgGroupPermissions['user']['move'];
                                }
                                $autoconfirmedCanMove = false;
                                if ( isset( $wgGroupPermissions['autoconfirmed']['move'] ) ) {
                                        $autoconfirmedCanMove = $wgGroupPermissions['autoconfirmed']['move'];
                                }
                                if ( $user->isAnon() && ( $userCanMove || $autoconfirmedCanMove ) ) {
                                        // custom message if logged-in users without any special rights can move
                                        $errors[] = array( 'movenologintext' );
                                } else {
                                        $errors[] = array( 'movenotallowed' );
                                }
                        }
                } elseif ( $action == 'move-target' ) {
                        if ( !$user->isAllowed( 'move' ) ) {
                                // User can't move anything
                                $errors[] = array( 'movenotallowed' );
                        } elseif ( !$user->isAllowed( 'move-rootuserpages' )
                                        && $this->mNamespace == NS_USER && !$this->isSubpage() ) {
                                // Show user page-specific message only if the user can move other pages
                                $errors[] = array( 'cant-move-to-user-page' );
                        }
                } elseif ( !$user->isAllowed( $action ) ) {
                        $errors[] = $this->missingPermissionError( $action, $short );
                }

                return $errors;
        }

        private function resultToError( $errors, $result ) {
                if ( is_array( $result ) && count( $result ) && !is_array( $result[0] ) ) {
                        // A single array representing an error
                        $errors[] = $result;
                } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
                        // A nested array representing multiple errors
                        $errors = array_merge( $errors, $result );
                } elseif ( $result !== '' && is_string( $result ) ) {
                        // A string representing a message-id
                        $errors[] = array( $result );
                } elseif ( $result === false ) {
                        // a generic "We don't want them to do that"
                        $errors[] = array( 'badaccess-group0' );
                }
                return $errors;
        }

        private function checkPermissionHooks( $action, $user, $errors, $doExpensiveQueries, $short ) {
                // Use getUserPermissionsErrors instead
                $result = '';
                if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
                        return $result ? array() : array( array( 'badaccess-group0' ) );
                }
                // Check getUserPermissionsErrors hook
                if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, &$user, $action, &$result ) ) ) {
                        $errors = $this->resultToError( $errors, $result );
                }
                // Check getUserPermissionsErrorsExpensive hook
                if ( $doExpensiveQueries && !( $short && count( $errors ) > 0 ) &&
                         !wfRunHooks( 'getUserPermissionsErrorsExpensive', array( &$this, &$user, $action, &$result ) ) ) {
                        $errors = $this->resultToError( $errors, $result );
                }

                return $errors;
        }

        private function checkSpecialsAndNSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
                # Only 'createaccount' and 'execute' can be performed on
                # special pages, which don't actually exist in the DB.
                $specialOKActions = array( 'createaccount', 'execute', 'read' );
                if ( NS_SPECIAL == $this->mNamespace && !in_array( $action, $specialOKActions ) ) {
                        $errors[] = array( 'ns-specialprotected' );
                }

                # Check $wgNamespaceProtection for restricted namespaces
                if ( $this->isNamespaceProtected( $user ) ) {
                        $ns = $this->mNamespace == NS_MAIN ?
                                wfMsg( 'nstab-main' ) : $this->getNsText();
                        $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
                                array( 'protectedinterface' ) : array( 'namespaceprotected',  $ns );
                }

                return $errors;
        }

        private function checkCSSandJSPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
                # Protect css/js subpages of user pages
                # XXX: this might be better using restrictions
                # XXX: right 'editusercssjs' is deprecated, for backward compatibility only
                if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' )
                                && !preg_match( '/^' . preg_quote( $user->getName(), '/' ) . '\//', $this->mTextform ) ) {
                        if ( $this->isCssSubpage() && !$user->isAllowed( 'editusercss' ) ) {
                                $errors[] = array( 'customcssprotected' );
                        } elseif ( $this->isJsSubpage() && !$user->isAllowed( 'edituserjs' ) ) {
                                $errors[] = array( 'customjsprotected' );
                        }
                }

                return $errors;
        }

        private function checkPageRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
                foreach ( $this->getRestrictions( $action ) as $right ) {
                        // Backwards compatibility, rewrite sysop -> protect
                        if ( $right == 'sysop' ) {
                                $right = 'protect';
                        }
                        if ( $right != '' && !$user->isAllowed( $right ) ) {
                                // Users with 'editprotected' permission can edit protected pages
                                // without cascading option turned on.
                                if ( $action != 'edit' || !$user->isAllowed( 'editprotected' )
                                        || $this->mCascadeRestriction )
                                {
                                        $errors[] = array( 'protectedpagetext', $right );
                                }
                        }
                }

                return $errors;
        }

        private function checkCascadingSourcesRestrictions( $action, $user, $errors, $doExpensiveQueries, $short ) {
                if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
                        # We /could/ use the protection level on the source page, but it's
                        # fairly ugly as we have to establish a precedence hierarchy for pages
                        # included by multiple cascade-protected pages. So just restrict
                        # it to people with 'protect' permission, as they could remove the
                        # protection anyway.
                        list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
                        # Cascading protection depends on more than this page...
                        # Several cascading protected pages may include this page...
                        # Check each cascading level
                        # This is only for protection restrictions, not for all actions
                        if ( isset( $restrictions[$action] ) ) {
                                foreach ( $restrictions[$action] as $right ) {
                                        $right = ( $right == 'sysop' ) ? 'protect' : $right;
                                        if ( $right != '' && !$user->isAllowed( $right ) ) {
                                                $pages = '';
                                                foreach ( $cascadingSources as $page )
                                                        $pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
                                                $errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
                                        }
                                }
                        }
                }

                return $errors;
        }

        private function checkActionPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
                global $wgDeleteRevisionsLimit, $wgLang;

                if ( $action == 'protect' ) {
                        if ( count( $this->getUserPermissionsErrorsInternal( 'edit', $user, $doExpensiveQueries, true ) ) ) {
                                // If they can't edit, they shouldn't protect.
                                $errors[] = array( 'protect-cantedit' );
                        }
                } elseif ( $action == 'create' ) {
                        $title_protection = $this->getTitleProtection();
                        if( $title_protection ) {
                                if( $title_protection['pt_create_perm'] == 'sysop' ) {
                                        $title_protection['pt_create_perm'] = 'protect'; // B/C
                                }
                                if( $title_protection['pt_create_perm'] == '' ||
                                        !$user->isAllowed( $title_protection['pt_create_perm'] ) ) 
                                {
                                        $errors[] = array( 'titleprotected', User::whoIs( $title_protection['pt_user'] ), $title_protection['pt_reason'] );
                                }
                        }
                } elseif ( $action == 'move' ) {
                        // Check for immobile pages
                        if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
                                // Specific message for this case
                                $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
                        } elseif ( !$this->isMovable() ) {
                                // Less specific message for rarer cases
                                $errors[] = array( 'immobile-source-page' );
                        }
                } elseif ( $action == 'move-target' ) {
                        if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
                                $errors[] = array( 'immobile-target-namespace', $this->getNsText() );
                        } elseif ( !$this->isMovable() ) {
                                $errors[] = array( 'immobile-target-page' );
                        }
                } elseif ( $action == 'delete' ) {
                        if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
                                && !$this->userCan( 'bigdelete', $user ) && $this->isBigDeletion() )
                        {
                                $errors[] = array( 'delete-toobig', $wgLang->formatNum( $wgDeleteRevisionsLimit ) );
                        }
                }
                return $errors;
        }

        private function checkUserBlock( $action, $user, $errors, $doExpensiveQueries, $short ) {
                // Account creation blocks handled at userlogin.
                // Unblocking handled in SpecialUnblock
                if( !$doExpensiveQueries || in_array( $action, array( 'createaccount', 'unblock' ) ) ) {
                        return $errors;
                }

                global $wgContLang, $wgLang, $wgEmailConfirmToEdit;

                if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
                        $errors[] = array( 'confirmedittext' );
                }

                if ( ( $action == 'edit' || $action == 'create' ) && !$user->isBlockedFrom( $this ) ) {
                        // Don't block the user from editing their own talk page unless they've been
                        // explicitly blocked from that too.
                } elseif( $user->isBlocked() && $user->mBlock->prevents( $action ) !== false ) {
                        $block = $user->mBlock;

                        // This is from OutputPage::blockedPage
                        // Copied at r23888 by werdna

                        $id = $user->blockedBy();
                        $reason = $user->blockedFor();
                        if ( $reason == '' ) {
                                $reason = wfMsg( 'blockednoreason' );
                        }
                        $ip = $user->getRequest()->getIP();

                        if ( is_numeric( $id ) ) {
                                $name = User::whoIs( $id );
                        } else {
                                $name = $id;
                        }

                        $link = '[[' . $wgContLang->getNsText( NS_USER ) . ":{$name}|{$name}]]";
                        $blockid = $block->getId();
                        $blockExpiry = $user->mBlock->mExpiry;
                        $blockTimestamp = $wgLang->timeanddate( wfTimestamp( TS_MW, $user->mBlock->mTimestamp ), true );
                        if ( $blockExpiry == 'infinity' ) {
                                $blockExpiry = wfMessage( 'infiniteblock' )->text();
                        } else {
                                $blockExpiry = $wgLang->timeanddate( wfTimestamp( TS_MW, $blockExpiry ), true );
                        }

                        $intended = strval( $user->mBlock->getTarget() );

                        $errors[] = array( ( $block->mAuto ? 'autoblockedtext' : 'blockedtext' ), $link, $reason, $ip, $name,
                                $blockid, $blockExpiry, $intended, $blockTimestamp );
                }

                return $errors;
        }

        private function checkReadPermissions( $action, $user, $errors, $doExpensiveQueries, $short ) {
                global $wgWhitelistRead, $wgGroupPermissions, $wgRevokePermissions;
                static $useShortcut = null;

                # Initialize the $useShortcut boolean, to determine if we can skip quite a bit of code below
                if ( is_null( $useShortcut ) ) {
                        $useShortcut = true;
                        if ( empty( $wgGroupPermissions['*']['read'] ) ) {
                                # Not a public wiki, so no shortcut
                                $useShortcut = false;
                        } elseif ( !empty( $wgRevokePermissions ) ) {
                                foreach ( $wgRevokePermissions as $perms ) {
                                        if ( !empty( $perms['read'] ) ) {
                                                # We might be removing the read right from the user, so no shortcut
                                                $useShortcut = false;
                                                break;
                                        }
                                }
                        }
                }

                $whitelisted = false;
                if ( $useShortcut ) {
                        # Shortcut for public wikis, allows skipping quite a bit of code
                        $whitelisted = true;
                } elseif ( $user->isAllowed( 'read' ) ) {
                        # If the user is allowed to read pages, he is allowed to read all pages
                        $whitelisted = true;
                } elseif ( $this->isSpecial( 'Userlogin' )
                        || $this->isSpecial( 'ChangePassword' )
                        || $this->isSpecial( 'PasswordReset' )
                ) {
                        # Always grant access to the login page.
                        # Even anons need to be able to log in.
                        $whitelisted = true;
                } elseif ( is_array( $wgWhitelistRead ) && count( $wgWhitelistRead ) ) {
                        # Time to check the whitelist
                        # Only do these checks is there's something to check against
                        $name = $this->getPrefixedText();
                        $dbName = $this->getPrefixedDBKey();

                        // Check with and without underscores
                        if ( in_array( $name, $wgWhitelistRead, true ) || in_array( $dbName, $wgWhitelistRead, true ) ) {
                                # Check for explicit whitelisting
                                $whitelisted = true;
                        } elseif ( $this->getNamespace() == NS_MAIN ) {
                                # Old settings might have the title prefixed with
                                # a colon for main-namespace pages
                                if ( in_array( ':' . $name, $wgWhitelistRead ) ) {
                                        $whitelisted = true;
                                }
                        } elseif ( $this->isSpecialPage() ) {
                                # If it's a special page, ditch the subpage bit and check again
                                $name = $this->getDBkey();
                                list( $name, /* $subpage */ ) = SpecialPageFactory::resolveAlias( $name );
                                if ( $name !== false ) {
                                        $pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
                                        if ( in_array( $pure, $wgWhitelistRead, true ) ) {
                                                $whitelisted = true;
                                        }
                                }
                        }
                }

                if ( !$whitelisted ) {
                        # If the title is not whitelisted, give extensions a chance to do so...
                        wfRunHooks( 'TitleReadWhitelist', array( $this, $user, &$whitelisted ) );
                        if ( !$whitelisted ) {
                                $errors[] = $this->missingPermissionError( $action, $short );
                        }
                }

                return $errors;
        }

        private function missingPermissionError( $action, $short ) {
                // We avoid expensive display logic for quickUserCan's and such
                if ( $short ) {
                        return array( 'badaccess-group0' );
                }

                $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
                        User::getGroupsWithPermission( $action ) );

                if ( count( $groups ) ) {
                        global $wgLang;
                        return array(
                                'badaccess-groups',
                                $wgLang->commaList( $groups ),
                                count( $groups )
                        );
                } else {
                        return array( 'badaccess-group0' );
                }
        }

        protected function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true, $short = false ) {
                wfProfileIn( __METHOD__ );

                # Read has special handling
                if ( $action == 'read' ) {
                        $checks = array(
                                'checkPermissionHooks',
                                'checkReadPermissions',
                        );
                } else {
                        $checks = array(
                                'checkQuickPermissions',
                                'checkPermissionHooks',
                                'checkSpecialsAndNSPermissions',
                                'checkCSSandJSPermissions',
                                'checkPageRestrictions',
                                'checkCascadingSourcesRestrictions',
                                'checkActionPermissions',
                                'checkUserBlock'
                        );
                }

                $errors = array();
                while( count( $checks ) > 0 &&
                                !( $short && count( $errors ) > 0 ) ) {
                        $method = array_shift( $checks );
                        $errors = $this->$method( $action, $user, $errors, $doExpensiveQueries, $short );
                }

                wfProfileOut( __METHOD__ );
                return $errors;
        }

        public function userCanEditCssSubpage() {
                global $wgUser;
                wfDeprecated( __METHOD__, '1.19' );
                return ( ( $wgUser->isAllowedAll( 'editusercssjs', 'editusercss' ) )
                        || preg_match( '/^' . preg_quote( $wgUser->getName(), '/' ) . '\//', $this->mTextform ) );
        }

        public function userCanEditJsSubpage() {
                global $wgUser;
                wfDeprecated( __METHOD__, '1.19' );
                return ( ( $wgUser->isAllowedAll( 'editusercssjs', 'edituserjs' ) )
                           || preg_match( '/^' . preg_quote( $wgUser->getName(), '/' ) . '\//', $this->mTextform ) );
        }

        public static function getFilteredRestrictionTypes( $exists = true ) {
                global $wgRestrictionTypes;
                $types = $wgRestrictionTypes;
                if ( $exists ) {
                        # Remove the create restriction for existing titles
                        $types = array_diff( $types, array( 'create' ) );
                } else {
                        # Only the create and upload restrictions apply to non-existing titles
                        $types = array_intersect( $types, array( 'create', 'upload' ) );
                }
                return $types;
        }

        public function getRestrictionTypes() {
                if ( $this->isSpecialPage() ) {
                        return array();
                }

                $types = self::getFilteredRestrictionTypes( $this->exists() );

                if ( $this->getNamespace() != NS_FILE ) {
                        # Remove the upload restriction for non-file titles
                        $types = array_diff( $types, array( 'upload' ) );
                }

                wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) );

                wfDebug( __METHOD__ . ': applicable restrictions to [[' .
                        $this->getPrefixedText() . ']] are {' . implode( ',', $types ) . "}\n" );

                return $types;
        }

        private function getTitleProtection() {
                // Can't protect pages in special namespaces
                if ( $this->getNamespace() < 0 ) {
                        return false;
                }

                // Can't protect pages that exist.
                if ( $this->exists() ) {
                        return false;
                }

                if ( !isset( $this->mTitleProtection ) ) {
                        $dbr = wfGetDB( DB_SLAVE );
                        $res = $dbr->select( 'protected_titles', '*',
                                array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
                                __METHOD__ );

                        // fetchRow returns false if there are no rows.
                        $this->mTitleProtection = $dbr->fetchRow( $res );
                }
                return $this->mTitleProtection;
        }

        public function updateTitleProtection( $create_perm, $reason, $expiry ) {
                wfDeprecated( __METHOD__, '1.19' );

                global $wgUser;

                $limit = array( 'create' => $create_perm );
                $expiry = array( 'create' => $expiry );

                $page = WikiPage::factory( $this );
                $status = $page->doUpdateRestrictions( $limit, $expiry, false, $reason, $wgUser );

                return $status->isOK();
        }

        public function deleteTitleProtection() {
                $dbw = wfGetDB( DB_MASTER );

                $dbw->delete(
                        'protected_titles',
                        array( 'pt_namespace' => $this->getNamespace(), 'pt_title' => $this->getDBkey() ),
                        __METHOD__
                );
                $this->mTitleProtection = false;
        }

        public function isSemiProtected( $action = 'edit' ) {
                if ( $this->exists() ) {
                        $restrictions = $this->getRestrictions( $action );
                        if ( count( $restrictions ) > 0 ) {
                                foreach ( $restrictions as $restriction ) {
                                        if ( strtolower( $restriction ) != 'autoconfirmed' ) {
                                                return false;
                                        }
                                }
                        } else {
                                # Not protected
                                return false;
                        }
                        return true;
                } else {
                        # If it doesn't exist, it can't be protected
                        return false;
                }
        }

        public function isProtected( $action = '' ) {
                global $wgRestrictionLevels;

                $restrictionTypes = $this->getRestrictionTypes();

                # Special pages have inherent protection
                if( $this->isSpecialPage() ) {
                        return true;
                }

                # Check regular protection levels
                foreach ( $restrictionTypes as $type ) {
                        if ( $action == $type || $action == '' ) {
                                $r = $this->getRestrictions( $type );
                                foreach ( $wgRestrictionLevels as $level ) {
                                        if ( in_array( $level, $r ) && $level != '' ) {
                                                return true;
                                        }
                                }
                        }
                }

                return false;
        }

        public function isNamespaceProtected( User $user ) {
                global $wgNamespaceProtection;

                if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
                        foreach ( (array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
                                if ( $right != '' && !$user->isAllowed( $right ) ) {
                                        return true;
                                }
                        }
                }
                return false;
        }

        public function isCascadeProtected() {
                list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
                return ( $sources > 0 );
        }

        public function getCascadeProtectionSources( $getPages = true ) {
                global $wgContLang;
                $pagerestrictions = array();

                if ( isset( $this->mCascadeSources ) && $getPages ) {
                        return array( $this->mCascadeSources, $this->mCascadingRestrictions );
                } elseif ( isset( $this->mHasCascadingRestrictions ) && !$getPages ) {
                        return array( $this->mHasCascadingRestrictions, $pagerestrictions );
                }

                wfProfileIn( __METHOD__ );

                $dbr = wfGetDB( DB_SLAVE );

                if ( $this->getNamespace() == NS_FILE ) {
                        $tables = array( 'imagelinks', 'page_restrictions' );
                        $where_clauses = array(
                                'il_to' => $this->getDBkey(),
                                'il_from=pr_page',
                                'pr_cascade' => 1
                        );
                } else {
                        $tables = array( 'templatelinks', 'page_restrictions' );
                        $where_clauses = array(
                                'tl_namespace' => $this->getNamespace(),
                                'tl_title' => $this->getDBkey(),
                                'tl_from=pr_page',
                                'pr_cascade' => 1
                        );
                }

                if ( $getPages ) {
                        $cols = array( 'pr_page', 'page_namespace', 'page_title',
                                                   'pr_expiry', 'pr_type', 'pr_level' );
                        $where_clauses[] = 'page_id=pr_page';
                        $tables[] = 'page';
                } else {
                        $cols = array( 'pr_expiry' );
                }

                $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );

                $sources = $getPages ? array() : false;
                $now = wfTimestampNow();
                $purgeExpired = false;

                foreach ( $res as $row ) {
                        $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );
                        if ( $expiry > $now ) {
                                if ( $getPages ) {
                                        $page_id = $row->pr_page;
                                        $page_ns = $row->page_namespace;
                                        $page_title = $row->page_title;
                                        $sources[$page_id] = Title::makeTitle( $page_ns, $page_title );
                                        # Add groups needed for each restriction type if its not already there
                                        # Make sure this restriction type still exists

                                        if ( !isset( $pagerestrictions[$row->pr_type] ) ) {
                                                $pagerestrictions[$row->pr_type] = array();
                                        }

                                        if ( isset( $pagerestrictions[$row->pr_type] ) &&
                                                 !in_array( $row->pr_level, $pagerestrictions[$row->pr_type] ) ) {
                                                $pagerestrictions[$row->pr_type][] = $row->pr_level;
                                        }
                                } else {
                                        $sources = true;
                                }
                        } else {
                                // Trigger lazy purge of expired restrictions from the db
                                $purgeExpired = true;
                        }
                }
                if ( $purgeExpired ) {
                        Title::purgeExpiredRestrictions();
                }

                if ( $getPages ) {
                        $this->mCascadeSources = $sources;
                        $this->mCascadingRestrictions = $pagerestrictions;
                } else {
                        $this->mHasCascadingRestrictions = $sources;
                }

                wfProfileOut( __METHOD__ );
                return array( $sources, $pagerestrictions );
        }

        public function getRestrictions( $action ) {
                if ( !$this->mRestrictionsLoaded ) {
                        $this->loadRestrictions();
                }
                return isset( $this->mRestrictions[$action] )
                                ? $this->mRestrictions[$action]
                                : array();
        }

        public function getRestrictionExpiry( $action ) {
                if ( !$this->mRestrictionsLoaded ) {
                        $this->loadRestrictions();
                }
                return isset( $this->mRestrictionsExpiry[$action] ) ? $this->mRestrictionsExpiry[$action] : false;
        }

        function areRestrictionsCascading() {
                if ( !$this->mRestrictionsLoaded ) {
                        $this->loadRestrictions();
                }

                return $this->mCascadeRestriction;
        }

        private function loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions = null ) {
                $rows = array();

                foreach ( $res as $row ) {
                        $rows[] = $row;
                }

                $this->loadRestrictionsFromRows( $rows, $oldFashionedRestrictions );
        }

        public function loadRestrictionsFromRows( $rows, $oldFashionedRestrictions = null ) {
                global $wgContLang;
                $dbr = wfGetDB( DB_SLAVE );

                $restrictionTypes = $this->getRestrictionTypes();

                foreach ( $restrictionTypes as $type ) {
                        $this->mRestrictions[$type] = array();
                        $this->mRestrictionsExpiry[$type] = $wgContLang->formatExpiry( '', TS_MW );
                }

                $this->mCascadeRestriction = false;

                # Backwards-compatibility: also load the restrictions from the page record (old format).

                if ( $oldFashionedRestrictions === null ) {
                        $oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions',
                                array( 'page_id' => $this->getArticleId() ), __METHOD__ );
                }

                if ( $oldFashionedRestrictions != '' ) {

                        foreach ( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
                                $temp = explode( '=', trim( $restrict ) );
                                if ( count( $temp ) == 1 ) {
                                        // old old format should be treated as edit/move restriction
                                        $this->mRestrictions['edit'] = explode( ',', trim( $temp[0] ) );
                                        $this->mRestrictions['move'] = explode( ',', trim( $temp[0] ) );
                                } else {
                                        $this->mRestrictions[$temp[0]] = explode( ',', trim( $temp[1] ) );
                                }
                        }

                        $this->mOldRestrictions = true;

                }

                if ( count( $rows ) ) {
                        # Current system - load second to make them override.
                        $now = wfTimestampNow();
                        $purgeExpired = false;

                        # Cycle through all the restrictions.
                        foreach ( $rows as $row ) {

                                // Don't take care of restrictions types that aren't allowed
                                if ( !in_array( $row->pr_type, $restrictionTypes ) )
                                        continue;

                                // This code should be refactored, now that it's being used more generally,
                                // But I don't really see any harm in leaving it in Block for now -werdna
                                $expiry = $wgContLang->formatExpiry( $row->pr_expiry, TS_MW );

                                // Only apply the restrictions if they haven't expired!
                                if ( !$expiry || $expiry > $now ) {
                                        $this->mRestrictionsExpiry[$row->pr_type] = $expiry;
                                        $this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );

                                        $this->mCascadeRestriction |= $row->pr_cascade;
                                } else {
                                        // Trigger a lazy purge of expired restrictions
                                        $purgeExpired = true;
                                }
                        }

                        if ( $purgeExpired ) {
                                Title::purgeExpiredRestrictions();
                        }
                }

                $this->mRestrictionsLoaded = true;
        }

        public function loadRestrictions( $oldFashionedRestrictions = null ) {
                global $wgContLang;
                if ( !$this->mRestrictionsLoaded ) {
                        if ( $this->exists() ) {
                                $dbr = wfGetDB( DB_SLAVE );

                                $res = $dbr->select(
                                        'page_restrictions',
                                        '*',
                                        array( 'pr_page' => $this->getArticleId() ),
                                        __METHOD__
                                );

                                $this->loadRestrictionsFromResultWrapper( $res, $oldFashionedRestrictions );
                        } else {
                                $title_protection = $this->getTitleProtection();

                                if ( $title_protection ) {
                                        $now = wfTimestampNow();
                                        $expiry = $wgContLang->formatExpiry( $title_protection['pt_expiry'], TS_MW );

                                        if ( !$expiry || $expiry > $now ) {
                                                // Apply the restrictions
                                                $this->mRestrictionsExpiry['create'] = $expiry;
                                                $this->mRestrictions['create'] = explode( ',', trim( $title_protection['pt_create_perm'] ) );
                                        } else { // Get rid of the old restrictions
                                                Title::purgeExpiredRestrictions();
                                                $this->mTitleProtection = false;
                                        }
                                } else {
                                        $this->mRestrictionsExpiry['create'] = $wgContLang->formatExpiry( '', TS_MW );
                                }
                                $this->mRestrictionsLoaded = true;
                        }
                }
        }

        public function flushRestrictions() {
                $this->mRestrictionsLoaded = false;
                $this->mTitleProtection = null;
        }

        static function purgeExpiredRestrictions() {
                $dbw = wfGetDB( DB_MASTER );
                $dbw->delete(
                        'page_restrictions',
                        array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
                        __METHOD__
                );

                $dbw->delete(
                        'protected_titles',
                        array( 'pt_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
                        __METHOD__
                );
        }

        public function hasSubpages() {
                if ( !MWNamespace::hasSubpages( $this->mNamespace ) ) {
                        # Duh
                        return false;
                }

                # We dynamically add a member variable for the purpose of this method
                # alone to cache the result.  There's no point in having it hanging
                # around uninitialized in every Title object; therefore we only add it
                # if needed and don't declare it statically.
                if ( isset( $this->mHasSubpages ) ) {
                        return $this->mHasSubpages;
                }

                $subpages = $this->getSubpages( 1 );
                if ( $subpages instanceof TitleArray ) {
                        return $this->mHasSubpages = (bool)$subpages->count();
                }
                return $this->mHasSubpages = false;
        }

        public function getSubpages( $limit = -1 ) {
                if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
                        return array();
                }

                $dbr = wfGetDB( DB_SLAVE );
                $conds['page_namespace'] = $this->getNamespace();
                $conds[] = 'page_title ' . $dbr->buildLike( $this->getDBkey() . '/', $dbr->anyString() );
                $options = array();
                if ( $limit > -1 ) {
                        $options['LIMIT'] = $limit;
                }
                return $this->mSubpages = TitleArray::newFromResult(
                        $dbr->select( 'page',
                                array( 'page_id', 'page_namespace', 'page_title', 'page_is_redirect' ),
                                $conds,
                                __METHOD__,
                                $options
                        )
                );
        }

        public function isDeleted() {
                if ( $this->getNamespace() < 0 ) {
                        $n = 0;
                } else {
                        $dbr = wfGetDB( DB_SLAVE );

                        $n = $dbr->selectField( 'archive', 'COUNT(*)',
                                array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
                                __METHOD__
                        );
                        if ( $this->getNamespace() == NS_FILE ) {
                                $n += $dbr->selectField( 'filearchive', 'COUNT(*)',
                                        array( 'fa_name' => $this->getDBkey() ),
                                        __METHOD__
                                );
                        }
                }
                return (int)$n;
        }

        public function isDeletedQuick() {
                if ( $this->getNamespace() < 0 ) {
                        return false;
                }
                $dbr = wfGetDB( DB_SLAVE );
                $deleted = (bool)$dbr->selectField( 'archive', '1',
                        array( 'ar_namespace' => $this->getNamespace(), 'ar_title' => $this->getDBkey() ),
                        __METHOD__
                );
                if ( !$deleted && $this->getNamespace() == NS_FILE ) {
                        $deleted = (bool)$dbr->selectField( 'filearchive', '1',
                                array( 'fa_name' => $this->getDBkey() ),
                                __METHOD__
                        );
                }
                return $deleted;
        }

        public function getArticleID( $flags = 0 ) {
                if ( $this->getNamespace() < 0 ) {
                        return $this->mArticleID = 0;
                }
                $linkCache = LinkCache::singleton();
                if ( $flags & self::GAID_FOR_UPDATE ) {
                        $oldUpdate = $linkCache->forUpdate( true );
                        $linkCache->clearLink( $this );
                        $this->mArticleID = $linkCache->addLinkObj( $this );
                        $linkCache->forUpdate( $oldUpdate );
                } else {
                        if ( -1 == $this->mArticleID ) {
                                $this->mArticleID = $linkCache->addLinkObj( $this );
                        }
                }
                return $this->mArticleID;
        }

        public function isRedirect( $flags = 0 ) {
                if ( !is_null( $this->mRedirect ) ) {
                        return $this->mRedirect;
                }
                # Calling getArticleID() loads the field from cache as needed
                if ( !$this->getArticleID( $flags ) ) {
                        return $this->mRedirect = false;
                }
                $linkCache = LinkCache::singleton();
                $this->mRedirect = (bool)$linkCache->getGoodLinkFieldObj( $this, 'redirect' );

                return $this->mRedirect;
        }

        public function getLength( $flags = 0 ) {
                if ( $this->mLength != -1 ) {
                        return $this->mLength;
                }
                # Calling getArticleID() loads the field from cache as needed
                if ( !$this->getArticleID( $flags ) ) {
                        return $this->mLength = 0;
                }
                $linkCache = LinkCache::singleton();
                $this->mLength = intval( $linkCache->getGoodLinkFieldObj( $this, 'length' ) );

                return $this->mLength;
        }

        public function getLatestRevID( $flags = 0 ) {
                if ( $this->mLatestID !== false ) {
                        return intval( $this->mLatestID );
                }
                # Calling getArticleID() loads the field from cache as needed
                if ( !$this->getArticleID( $flags ) ) {
                        return $this->mLatestID = 0;
                }
                $linkCache = LinkCache::singleton();
                $this->mLatestID = intval( $linkCache->getGoodLinkFieldObj( $this, 'revision' ) );

                return $this->mLatestID;
        }

        public function resetArticleID( $newid ) {
                $linkCache = LinkCache::singleton();
                $linkCache->clearLink( $this );

                if ( $newid === false ) {
                        $this->mArticleID = -1;
                } else {
                        $this->mArticleID = intval( $newid );
                }
                $this->mRestrictionsLoaded = false;
                $this->mRestrictions = array();
                $this->mRedirect = null;
                $this->mLength = -1;
                $this->mLatestID = false;
                $this->mEstimateRevisions = null;
        }

        public static function capitalize( $text, $ns = NS_MAIN ) {
                global $wgContLang;

                if ( MWNamespace::isCapitalized( $ns ) ) {
                        return $wgContLang->ucfirst( $text );
                } else {
                        return $text;
                }
        }

        private function secureAndSplit() {
                global $wgContLang, $wgLocalInterwiki;

                # Initialisation
                $this->mInterwiki = $this->mFragment = '';
                $this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN

                $dbkey = $this->mDbkeyform;

                # Strip Unicode bidi override characters.
                # Sometimes they slip into cut-n-pasted page titles, where the
                # override chars get included in list displays.
                $dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );

                # Clean up whitespace
                # Note: use of the /u option on preg_replace here will cause
                # input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
                # conveniently disabling them.
                $dbkey = preg_replace( '/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u', '_', $dbkey );
                $dbkey = trim( $dbkey, '_' );

                if ( $dbkey == '' ) {
                        return false;
                }

                if ( false !== strpos( $dbkey, UTF8_REPLACEMENT ) ) {
                        # Contained illegal UTF-8 sequences or forbidden Unicode chars.
                        return false;
                }

                $this->mDbkeyform = $dbkey;

                # Initial colon indicates main namespace rather than specified default
                # but should not create invalid {ns,title} pairs such as {0,Project:Foo}
                if ( ':' == $dbkey[0] ) {
                        $this->mNamespace = NS_MAIN;
                        $dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
                        $dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
                }

                # Namespace or interwiki prefix
                $firstPass = true;
                $prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
                do {
                        $m = array();
                        if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
                                $p = $m[1];
                                if ( ( $ns = $wgContLang->getNsIndex( $p ) ) !== false ) {
                                        # Ordinary namespace
                                        $dbkey = $m[2];
                                        $this->mNamespace = $ns;
                                        # For Talk:X pages, check if X has a "namespace" prefix
                                        if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
                                                if ( $wgContLang->getNsIndex( $x[1] ) ) {
                                                        # Disallow Talk:File:x type titles...
                                                        return false;
                                                } elseif ( Interwiki::isValidInterwiki( $x[1] ) ) {
                                                        # Disallow Talk:Interwiki:x type titles...
                                                        return false;
                                                }
                                        }
                                } elseif ( Interwiki::isValidInterwiki( $p ) ) {
                                        if ( !$firstPass ) {
                                                # Can't make a local interwiki link to an interwiki link.
                                                # That's just crazy!
                                                return false;
                                        }

                                        # Interwiki link
                                        $dbkey = $m[2];
                                        $this->mInterwiki = $wgContLang->lc( $p );

                                        # Redundant interwiki prefix to the local wiki
                                        if ( $wgLocalInterwiki !== false
                                                && 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki ) )
                                        {
                                                if ( $dbkey == '' ) {
                                                        # Can't have an empty self-link
                                                        return false;
                                                }
                                                $this->mInterwiki = '';
                                                $firstPass = false;
                                                # Do another namespace split...
                                                continue;
                                        }

                                        # If there's an initial colon after the interwiki, that also
                                        # resets the default namespace
                                        if ( $dbkey !== '' && $dbkey[0] == ':' ) {
                                                $this->mNamespace = NS_MAIN;
                                                $dbkey = substr( $dbkey, 1 );
                                        }
                                }
                                # If there's no recognized interwiki or namespace,
                                # then let the colon expression be part of the title.
                        }
                        break;
                } while ( true );

                # We already know that some pages won't be in the database!
                if ( $this->mInterwiki != '' || NS_SPECIAL == $this->mNamespace ) {
                        $this->mArticleID = 0;
                }
                $fragment = strstr( $dbkey, '#' );
                if ( false !== $fragment ) {
                        $this->setFragment( $fragment );
                        $dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
                        # remove whitespace again: prevents "Foo_bar_#"
                        # becoming "Foo_bar_"
                        $dbkey = preg_replace( '/_*$/', '', $dbkey );
                }

                # Reject illegal characters.
                $rxTc = self::getTitleInvalidRegex();
                if ( preg_match( $rxTc, $dbkey ) ) {
                        return false;
                }

                # Pages with "/./" or "/../" appearing in the URLs will often be un-
                # reachable due to the way web browsers deal with 'relative' URLs.
                # Also, they conflict with subpage syntax.  Forbid them explicitly.
                if ( strpos( $dbkey, '.' ) !== false &&
                         ( $dbkey === '.' || $dbkey === '..' ||
                           strpos( $dbkey, './' ) === 0  ||
                           strpos( $dbkey, '../' ) === 0 ||
                           strpos( $dbkey, '/./' ) !== false ||
                           strpos( $dbkey, '/../' ) !== false  ||
                           substr( $dbkey, -2 ) == '/.' ||
                           substr( $dbkey, -3 ) == '/..' ) )
                {
                        return false;
                }

                # Magic tilde sequences? Nu-uh!
                if ( strpos( $dbkey, '~~~' ) !== false ) {
                        return false;
                }

                # Limit the size of titles to 255 bytes. This is typically the size of the
                # underlying database field. We make an exception for special pages, which
                # don't need to be stored in the database, and may edge over 255 bytes due
                # to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
                if ( ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 ) ||
                  strlen( $dbkey ) > 512 )
                {
                        return false;
                }

                # Normally, all wiki links are forced to have an initial capital letter so [[foo]]
                # and [[Foo]] point to the same place.  Don't force it for interwikis, since the
                # other site might be case-sensitive.
                $this->mUserCaseDBKey = $dbkey;
                if ( $this->mInterwiki == '' ) {
                        $dbkey = self::capitalize( $dbkey, $this->mNamespace );
                }

                # Can't make a link to a namespace alone... "empty" local links can only be
                # self-links with a fragment identifier.
                if ( $dbkey == '' && $this->mInterwiki == '' && $this->mNamespace != NS_MAIN ) {
                        return false;
                }

                // Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
                // IP names are not allowed for accounts, and can only be referring to
                // edits from the IP. Given '::' abbreviations and caps/lowercaps,
                // there are numerous ways to present the same IP. Having sp:contribs scan
                // them all is silly and having some show the edits and others not is
                // inconsistent. Same for talk/userpages. Keep them normalized instead.
                $dbkey = ( $this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK )
                        ? IP::sanitizeIP( $dbkey )
                        : $dbkey;

                // Any remaining initial :s are illegal.
                if ( $dbkey !== '' && ':' == $dbkey[0] ) {
                        return false;
                }

                # Fill fields
                $this->mDbkeyform = $dbkey;
                $this->mUrlform = wfUrlencode( $dbkey );

                $this->mTextform = str_replace( '_', ' ', $dbkey );

                return true;
        }

        public function getLinksTo( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
                if ( count( $options ) > 0 ) {
                        $db = wfGetDB( DB_MASTER );
                } else {
                        $db = wfGetDB( DB_SLAVE );
                }

                $res = $db->select(
                        array( 'page', $table ),
                        array( 'page_namespace', 'page_title', 'page_id', 'page_len', 'page_is_redirect', 'page_latest' ),
                        array(
                                "{$prefix}_from=page_id",
                                "{$prefix}_namespace" => $this->getNamespace(),
                                "{$prefix}_title"     => $this->getDBkey() ),
                        __METHOD__,
                        $options
                );

                $retVal = array();
                if ( $res->numRows() ) {
                        $linkCache = LinkCache::singleton();
                        foreach ( $res as $row ) {
                                $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title );
                                if ( $titleObj ) {
                                        $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
                                        $retVal[] = $titleObj;
                                }
                        }
                }
                return $retVal;
        }

        public function getTemplateLinksTo( $options = array() ) {
                return $this->getLinksTo( $options, 'templatelinks', 'tl' );
        }

        public function getLinksFrom( $options = array(), $table = 'pagelinks', $prefix = 'pl' ) {
                $id = $this->getArticleId();

                # If the page doesn't exist; there can't be any link from this page
                if ( !$id ) {
                        return array();
                }

                if ( count( $options ) > 0 ) {
                        $db = wfGetDB( DB_MASTER );
                } else {
                        $db = wfGetDB( DB_SLAVE );
                }

                $namespaceFiled = "{$prefix}_namespace";
                $titleField = "{$prefix}_title";

                $res = $db->select(
                        array( $table, 'page' ),
                        array( $namespaceFiled, $titleField, 'page_id', 'page_len', 'page_is_redirect', 'page_latest' ),
                        array( "{$prefix}_from" => $id ),
                        __METHOD__,
                        $options,
                        array( 'page' => array( 'LEFT JOIN', array( "page_namespace=$namespaceFiled", "page_title=$titleField" ) ) )
                );

                $retVal = array();
                if ( $res->numRows() ) {
                        $linkCache = LinkCache::singleton();
                        foreach ( $res as $row ) {
                                $titleObj = Title::makeTitle( $row->$namespaceFiled, $row->$titleField );
                                if ( $titleObj ) {
                                        if ( $row->page_id ) {
                                                $linkCache->addGoodLinkObjFromRow( $titleObj, $row );
                                        } else {
                                                $linkCache->addBadLinkObj( $titleObj );
                                        }
                                        $retVal[] = $titleObj;
                                }
                        }
                }
                return $retVal;
        }

        public function getTemplateLinksFrom( $options = array() ) {
                return $this->getLinksFrom( $options, 'templatelinks', 'tl' );
        }

        public function getBrokenLinksFrom() {
                if ( $this->getArticleId() == 0 ) {
                        # All links from article ID 0 are false positives
                        return array();
                }

                $dbr = wfGetDB( DB_SLAVE );
                $res = $dbr->select(
                        array( 'page', 'pagelinks' ),
                        array( 'pl_namespace', 'pl_title' ),
                        array(
                                'pl_from' => $this->getArticleId(),
                                'page_namespace IS NULL'
                        ),
                        __METHOD__, array(),
                        array(
                                'page' => array(
                                        'LEFT JOIN',
                                        array( 'pl_namespace=page_namespace', 'pl_title=page_title' )
                                )
                        )
                );

                $retVal = array();
                foreach ( $res as $row ) {
                        $retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
                }
                return $retVal;
        }


        public function getSquidURLs() {
                global $wgContLang;

                $urls = array(
                        $this->getInternalURL(),
                        $this->getInternalURL( 'action=history' )
                );

                // purge variant urls as well
                if ( $wgContLang->hasVariants() ) {
                        $variants = $wgContLang->getVariants();
                        foreach ( $variants as $vCode ) {
                                $urls[] = $this->getInternalURL( '', $vCode );
                        }
                }

                return $urls;
        }

        public function purgeSquid() {
                global $wgUseSquid;
                if ( $wgUseSquid ) {
                        $urls = $this->getSquidURLs();
                        $u = new SquidUpdate( $urls );
                        $u->doUpdate();
                }
        }

        public function moveNoAuth( &$nt ) {
                return $this->moveTo( $nt, false );
        }

        public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
                global $wgUser;

                $errors = array();
                if ( !$nt ) {
                        // Normally we'd add this to $errors, but we'll get
                        // lots of syntax errors if $nt is not an object
                        return array( array( 'badtitletext' ) );
                }
                if ( $this->equals( $nt ) ) {
                        $errors[] = array( 'selfmove' );
                }
                if ( !$this->isMovable() ) {
                        $errors[] = array( 'immobile-source-namespace', $this->getNsText() );
                }
                if ( $nt->getInterwiki() != '' ) {
                        $errors[] = array( 'immobile-target-namespace-iw' );
                }
                if ( !$nt->isMovable() ) {
                        $errors[] = array( 'immobile-target-namespace', $nt->getNsText() );
                }

                $oldid = $this->getArticleID();
                $newid = $nt->getArticleID();

                if ( strlen( $nt->getDBkey() ) < 1 ) {
                        $errors[] = array( 'articleexists' );
                }
                if ( ( $this->getDBkey() == '' ) ||
                         ( !$oldid ) ||
                         ( $nt->getDBkey() == '' ) ) {
                        $errors[] = array( 'badarticleerror' );
                }

                // Image-specific checks
                if ( $this->getNamespace() == NS_FILE ) {
                        $errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
                }

                if ( $nt->getNamespace() == NS_FILE && $this->getNamespace() != NS_FILE ) {
                        $errors[] = array( 'nonfile-cannot-move-to-file' );
                }

                if ( $auth ) {
                        $errors = wfMergeErrorArrays( $errors,
                                $this->getUserPermissionsErrors( 'move', $wgUser ),
                                $this->getUserPermissionsErrors( 'edit', $wgUser ),
                                $nt->getUserPermissionsErrors( 'move-target', $wgUser ),
                                $nt->getUserPermissionsErrors( 'edit', $wgUser ) );
                }

                $match = EditPage::matchSummarySpamRegex( $reason );
                if ( $match !== false ) {
                        // This is kind of lame, won't display nice
                        $errors[] = array( 'spamprotectiontext' );
                }

                $err = null;
                if ( !wfRunHooks( 'AbortMove', array( $this, $nt, $wgUser, &$err, $reason ) ) ) {
                        $errors[] = array( 'hookaborted', $err );
                }

                # The move is allowed only if (1) the target doesn't exist, or
                # (2) the target is a redirect to the source, and has no history
                # (so we can undo bad moves right after they're done).

                if ( 0 != $newid ) { # Target exists; check for validity
                        if ( !$this->isValidMoveTarget( $nt ) ) {
                                $errors[] = array( 'articleexists' );
                        }
                } else {
                        $tp = $nt->getTitleProtection();
                        $right = ( $tp['pt_create_perm'] == 'sysop' ) ? 'protect' : $tp['pt_create_perm'];
                        if ( $tp and !$wgUser->isAllowed( $right ) ) {
                                $errors[] = array( 'cantmove-titleprotected' );
                        }
                }
                if ( empty( $errors ) ) {
                        return true;
                }
                return $errors;
        }

        protected function validateFileMoveOperation( $nt ) {
                global $wgUser;

                $errors = array();

                // wfFindFile( $nt ) / wfLocalFile( $nt ) is not allowed until below

                $file = wfLocalFile( $this );
                if ( $file->exists() ) {
                        if ( $nt->getText() != wfStripIllegalFilenameChars( $nt->getText() ) ) {
                                $errors[] = array( 'imageinvalidfilename' );
                        }
                        if ( !File::checkExtensionCompatibility( $file, $nt->getDBkey() ) ) {
                                $errors[] = array( 'imagetypemismatch' );
                        }
                }

                if ( $nt->getNamespace() != NS_FILE ) {
                        $errors[] = array( 'imagenocrossnamespace' );
                        // From here we want to do checks on a file object, so if we can't
                        // create one, we must return.
                        return $errors;
                }

                // wfFindFile( $nt ) / wfLocalFile( $nt ) is allowed below here

                $destFile = wfLocalFile( $nt );
                if ( !$wgUser->isAllowed( 'reupload-shared' ) && !$destFile->exists() && wfFindFile( $nt ) ) {
                        $errors[] = array( 'file-exists-sharedrepo' );
                }

                return $errors;
        }

        public function moveTo( &$nt, $auth = true, $reason = '', $createRedirect = true ) {
                global $wgUser;
                $err = $this->isValidMoveOperation( $nt, $auth, $reason );
                if ( is_array( $err ) ) {
                        // Auto-block user's IP if the account was "hard" blocked
                        $wgUser->spreadAnyEditBlock();
                        return $err;
                }

                // If it is a file, move it first.
                // It is done before all other moving stuff is done because it's hard to revert.
                $dbw = wfGetDB( DB_MASTER );
                if ( $this->getNamespace() == NS_FILE ) {
                        $file = wfLocalFile( $this );
                        if ( $file->exists() ) {
                                $status = $file->move( $nt );
                                if ( !$status->isOk() ) {
                                        return $status->getErrorsArray();
                                }
                        }
                        // Clear RepoGroup process cache
                        RepoGroup::singleton()->clearCache( $this );
                        RepoGroup::singleton()->clearCache( $nt ); # clear false negative cache
                }

                $dbw->begin(); # If $file was a LocalFile, its transaction would have closed our own.
                $pageid = $this->getArticleID( self::GAID_FOR_UPDATE );
                $protected = $this->isProtected();

                // Do the actual move
                $err = $this->moveToInternal( $nt, $reason, $createRedirect );
                if ( is_array( $err ) ) {
                        # @todo FIXME: What about the File we have already moved?
                        $dbw->rollback();
                        return $err;
                }

                // Refresh the sortkey for this row.  Be careful to avoid resetting
                // cl_timestamp, which may disturb time-based lists on some sites.
                $prefixes = $dbw->select(
                        'categorylinks',
                        array( 'cl_sortkey_prefix', 'cl_to' ),
                        array( 'cl_from' => $pageid ),
                        __METHOD__
                );
                foreach ( $prefixes as $prefixRow ) {
                        $prefix = $prefixRow->cl_sortkey_prefix;
                        $catTo = $prefixRow->cl_to;
                        $dbw->update( 'categorylinks',
                                array(
                                        'cl_sortkey' => Collation::singleton()->getSortKey(
                                                $nt->getCategorySortkey( $prefix ) ),
                                        'cl_timestamp=cl_timestamp' ),
                                array(
                                        'cl_from' => $pageid,
                                        'cl_to' => $catTo ),
                                __METHOD__
                        );
                }

                $redirid = $this->getArticleID();

                if ( $protected ) {
                        # Protect the redirect title as the title used to be...
                        $dbw->insertSelect( 'page_restrictions', 'page_restrictions',
                                array(
                                        'pr_page'    => $redirid,
                                        'pr_type'    => 'pr_type',
                                        'pr_level'   => 'pr_level',
                                        'pr_cascade' => 'pr_cascade',
                                        'pr_user'    => 'pr_user',
                                        'pr_expiry'  => 'pr_expiry'
                                ),
                                array( 'pr_page' => $pageid ),
                                __METHOD__,
                                array( 'IGNORE' )
                        );
                        # Update the protection log
                        $log = new LogPage( 'protect' );
                        $comment = wfMsgForContent( 'prot_1movedto2', $this->getPrefixedText(), $nt->getPrefixedText() );
                        if ( $reason ) {
                                $comment .= wfMsgForContent( 'colon-separator' ) . $reason;
                        }
                        // @todo FIXME: $params?
                        $log->addEntry( 'move_prot', $nt, $comment, array( $this->getPrefixedText() ) );
                }

                # Update watchlists
                $oldnamespace = $this->getNamespace() & ~1;
                $newnamespace = $nt->getNamespace() & ~1;
                $oldtitle = $this->getDBkey();
                $newtitle = $nt->getDBkey();

                if ( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
                        WatchedItem::duplicateEntries( $this, $nt );
                }

                $dbw->commit();

                wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
                return true;
        }

        private function moveToInternal( &$nt, $reason = '', $createRedirect = true ) {
                global $wgUser, $wgContLang;

                if ( $nt->exists() ) {
                        $moveOverRedirect = true;
                        $logType = 'move_redir';
                } else {
                        $moveOverRedirect = false;
                        $logType = 'move';
                }

                $redirectSuppressed = !$createRedirect && $wgUser->isAllowed( 'suppressredirect' );

                $logEntry = new ManualLogEntry( 'move', $logType );
                $logEntry->setPerformer( $wgUser );
                $logEntry->setTarget( $this );
                $logEntry->setComment( $reason );
                $logEntry->setParameters( array(
                        '4::target' => $nt->getPrefixedText(),
                        '5::noredir' => $redirectSuppressed ? '1': '0',
                ) );

                $formatter = LogFormatter::newFromEntry( $logEntry );
                $formatter->setContext( RequestContext::newExtraneousContext( $this ) );
                $comment = $formatter->getPlainActionText();
                if ( $reason ) {
                        $comment .= wfMsgForContent( 'colon-separator' ) . $reason;
                }
                # Truncate for whole multibyte characters.
                $comment = $wgContLang->truncate( $comment, 255 );

                $oldid = $this->getArticleID();
                $latest = $this->getLatestRevID();

                $dbw = wfGetDB( DB_MASTER );

                $newpage = WikiPage::factory( $nt );

                if ( $moveOverRedirect ) {
                        $newid = $nt->getArticleID();

                        # Delete the old redirect. We don't save it to history since
                        # by definition if we've got here it's rather uninteresting.
                        # We have to remove it so that the next step doesn't trigger
                        # a conflict on the unique namespace+title index...
                        $dbw->delete( 'page', array( 'page_id' => $newid ), __METHOD__ );

                        $newpage->doDeleteUpdates( $newid );
                }

                # Save a null revision in the page's history notifying of the move
                $nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
                if ( !is_object( $nullRevision ) ) {
                        throw new MWException( 'No valid null revision produced in ' . __METHOD__ );
                }
                $nullRevId = $nullRevision->insertOn( $dbw );

                # Change the name of the target page:
                $dbw->update( 'page',
                        /* SET */ array(
                                'page_namespace' => $nt->getNamespace(),
                                'page_title'     => $nt->getDBkey(),
                        ),
                        /* WHERE */ array( 'page_id' => $oldid ),
                        __METHOD__
                );

                $this->resetArticleID( 0 );
                $nt->resetArticleID( $oldid );

                $newpage->updateRevisionOn( $dbw, $nullRevision );

                wfRunHooks( 'NewRevisionFromEditComplete',
                        array( $newpage, $nullRevision, $latest, $wgUser ) );

                $newpage->doEditUpdates( $nullRevision, $wgUser, array( 'changed' => false ) );

                if ( !$moveOverRedirect ) {
                        WikiPage::onArticleCreate( $nt );
                }

                # Recreate the redirect, this time in the other direction.
                if ( $redirectSuppressed ) {
                        WikiPage::onArticleDelete( $this );
                } else {
                        $mwRedir = MagicWord::get( 'redirect' );
                        $redirectText = $mwRedir->getSynonym( 0 ) . ' [[' . $nt->getPrefixedText() . "]]\n";
                        $redirectArticle = WikiPage::factory( $this );
                        $newid = $redirectArticle->insertOn( $dbw );
                        if ( $newid ) { // sanity
                                $redirectRevision = new Revision( array(
                                        'page'    => $newid,
                                        'comment' => $comment,
                                        'text'    => $redirectText ) );
                                $redirectRevision->insertOn( $dbw );
                                $redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );

                                wfRunHooks( 'NewRevisionFromEditComplete',
                                        array( $redirectArticle, $redirectRevision, false, $wgUser ) );

                                $redirectArticle->doEditUpdates( $redirectRevision, $wgUser, array( 'created' => true ) );
                        }
                }

                # Log the move
                $logid = $logEntry->insert();
                $logEntry->publish( $logid );
        }

        public function moveSubpages( $nt, $auth = true, $reason = '', $createRedirect = true ) {
                global $wgMaximumMovedPages;
                // Check permissions
                if ( !$this->userCan( 'move-subpages' ) ) {
                        return array( 'cant-move-subpages' );
                }
                // Do the source and target namespaces support subpages?
                if ( !MWNamespace::hasSubpages( $this->getNamespace() ) ) {
                        return array( 'namespace-nosubpages',
                                MWNamespace::getCanonicalName( $this->getNamespace() ) );
                }
                if ( !MWNamespace::hasSubpages( $nt->getNamespace() ) ) {
                        return array( 'namespace-nosubpages',
                                MWNamespace::getCanonicalName( $nt->getNamespace() ) );
                }

                $subpages = $this->getSubpages( $wgMaximumMovedPages + 1 );
                $retval = array();
                $count = 0;
                foreach ( $subpages as $oldSubpage ) {
                        $count++;
                        if ( $count > $wgMaximumMovedPages ) {
                                $retval[$oldSubpage->getPrefixedTitle()] =
                                                array( 'movepage-max-pages',
                                                        $wgMaximumMovedPages );
                                break;
                        }

                        // We don't know whether this function was called before
                        // or after moving the root page, so check both
                        // $this and $nt
                        if ( $oldSubpage->getArticleId() == $this->getArticleId() ||
                                        $oldSubpage->getArticleID() == $nt->getArticleId() )
                        {
                                // When moving a page to a subpage of itself,
                                // don't move it twice
                                continue;
                        }
                        $newPageName = preg_replace(
                                        '#^' . preg_quote( $this->getDBkey(), '#' ) . '#',
                                        StringUtils::escapeRegexReplacement( $nt->getDBkey() ), # bug 21234
                                        $oldSubpage->getDBkey() );
                        if ( $oldSubpage->isTalkPage() ) {
                                $newNs = $nt->getTalkPage()->getNamespace();
                        } else {
                                $newNs = $nt->getSubjectPage()->getNamespace();
                        }
                        # Bug 14385: we need makeTitleSafe because the new page names may
                        # be longer than 255 characters.
                        $newSubpage = Title::makeTitleSafe( $newNs, $newPageName );

                        $success = $oldSubpage->moveTo( $newSubpage, $auth, $reason, $createRedirect );
                        if ( $success === true ) {
                                $retval[$oldSubpage->getPrefixedText()] = $newSubpage->getPrefixedText();
                        } else {
                                $retval[$oldSubpage->getPrefixedText()] = $success;
                        }
                }
                return $retval;
        }

        public function isSingleRevRedirect() {
                $dbw = wfGetDB( DB_MASTER );
                # Is it a redirect?
                $row = $dbw->selectRow( 'page',
                        array( 'page_is_redirect', 'page_latest', 'page_id' ),
                        $this->pageCond(),
                        __METHOD__,
                        array( 'FOR UPDATE' )
                );
                # Cache some fields we may want
                $this->mArticleID = $row ? intval( $row->page_id ) : 0;
                $this->mRedirect = $row ? (bool)$row->page_is_redirect : false;
                $this->mLatestID = $row ? intval( $row->page_latest ) : false;
                if ( !$this->mRedirect ) {
                        return false;
                }
                # Does the article have a history?
                $row = $dbw->selectField( array( 'page', 'revision' ),
                        'rev_id',
                        array( 'page_namespace' => $this->getNamespace(),
                                'page_title' => $this->getDBkey(),
                                'page_id=rev_page',
                                'page_latest != rev_id'
                        ),
                        __METHOD__,
                        array( 'FOR UPDATE' )
                );
                # Return true if there was no history
                return ( $row === false );
        }

        public function isValidMoveTarget( $nt ) {
                # Is it an existing file?
                if ( $nt->getNamespace() == NS_FILE ) {
                        $file = wfLocalFile( $nt );
                        if ( $file->exists() ) {
                                wfDebug( __METHOD__ . ": file exists\n" );
                                return false;
                        }
                }
                # Is it a redirect with no history?
                if ( !$nt->isSingleRevRedirect() ) {
                        wfDebug( __METHOD__ . ": not a one-rev redirect\n" );
                        return false;
                }
                # Get the article text
                $rev = Revision::newFromTitle( $nt );
                if( !is_object( $rev ) ){
                        return false;
                }
                $text = $rev->getText();
                # Does the redirect point to the source?
                # Or is it a broken self-redirect, usually caused by namespace collisions?
                $m = array();
                if ( preg_match( "/\\[\\[\\s*([^\\]\\|]*)]]/", $text, $m ) ) {
                        $redirTitle = Title::newFromText( $m[1] );
                        if ( !is_object( $redirTitle ) ||
                                ( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
                                $redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) ) {
                                wfDebug( __METHOD__ . ": redirect points to other page\n" );
                                return false;
                        }
                } else {
                        # Fail safe
                        wfDebug( __METHOD__ . ": failsafe\n" );
                        return false;
                }
                return true;
        }

        public function getParentCategories() {
                global $wgContLang;

                $data = array();

                $titleKey = $this->getArticleId();

                if ( $titleKey === 0 ) {
                        return $data;
                }

                $dbr = wfGetDB( DB_SLAVE );

                $res = $dbr->select( 'categorylinks', '*',
                        array(
                                'cl_from' => $titleKey,
                        ),
                        __METHOD__,
                        array()
                );

                if ( $dbr->numRows( $res ) > 0 ) {
                        foreach ( $res as $row ) {
                                // $data[] = Title::newFromText($wgContLang->getNSText ( NS_CATEGORY ).':'.$row->cl_to);
                                $data[$wgContLang->getNSText( NS_CATEGORY ) . ':' . $row->cl_to] = $this->getFullText();
                        }
                }
                return $data;
        }

        public function getParentCategoryTree( $children = array() ) {
                $stack = array();
                $parents = $this->getParentCategories();

                if ( $parents ) {
                        foreach ( $parents as $parent => $current ) {
                                if ( array_key_exists( $parent, $children ) ) {
                                        # Circular reference
                                        $stack[$parent] = array();
                                } else {
                                        $nt = Title::newFromText( $parent );
                                        if ( $nt ) {
                                                $stack[$parent] = $nt->getParentCategoryTree( $children + array( $parent => 1 ) );
                                        }
                                }
                        }
                }

                return $stack;
        }

        public function pageCond() {
                if ( $this->mArticleID > 0 ) {
                        // PK avoids secondary lookups in InnoDB, shouldn't hurt other DBs
                        return array( 'page_id' => $this->mArticleID );
                } else {
                        return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
                }
        }

        public function getPreviousRevisionID( $revId, $flags = 0 ) {
                $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
                return $db->selectField( 'revision', 'rev_id',
                        array(
                                'rev_page' => $this->getArticleId( $flags ),
                                'rev_id < ' . intval( $revId )
                        ),
                        __METHOD__,
                        array( 'ORDER BY' => 'rev_id DESC' )
                );
        }

        public function getNextRevisionID( $revId, $flags = 0 ) {
                $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
                return $db->selectField( 'revision', 'rev_id',
                        array(
                                'rev_page' => $this->getArticleId( $flags ),
                                'rev_id > ' . intval( $revId )
                        ),
                        __METHOD__,
                        array( 'ORDER BY' => 'rev_id' )
                );
        }

        public function getFirstRevision( $flags = 0 ) {
                $pageId = $this->getArticleId( $flags );
                if ( $pageId ) {
                        $db = ( $flags & self::GAID_FOR_UPDATE ) ? wfGetDB( DB_MASTER ) : wfGetDB( DB_SLAVE );
                        $row = $db->selectRow( 'revision', '*',
                                array( 'rev_page' => $pageId ),
                                __METHOD__,
                                array( 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 1 )
                        );
                        if ( $row ) {
                                return new Revision( $row );
                        }
                }
                return null;
        }

        public function getEarliestRevTime( $flags = 0 ) {
                $rev = $this->getFirstRevision( $flags );
                return $rev ? $rev->getTimestamp() : null;
        }

        public function isNewPage() {
                $dbr = wfGetDB( DB_SLAVE );
                return (bool)$dbr->selectField( 'page', 'page_is_new', $this->pageCond(), __METHOD__ );
        }

        public function isBigDeletion() {
                global $wgDeleteRevisionsLimit;

                if ( !$wgDeleteRevisionsLimit ) {
                        return false;
                }

                $revCount = $this->estimateRevisionCount();
                return $revCount > $wgDeleteRevisionsLimit;
        }

        public function estimateRevisionCount() {
                if ( !$this->exists() ) {
                        return 0;
                }

                if ( $this->mEstimateRevisions === null ) {
                        $dbr = wfGetDB( DB_SLAVE );
                        $this->mEstimateRevisions = $dbr->estimateRowCount( 'revision', '*',
                                array( 'rev_page' => $this->getArticleId() ), __METHOD__ );
                }

                return $this->mEstimateRevisions;
        }

        public function countRevisionsBetween( $old, $new ) {
                if ( !( $old instanceof Revision ) ) {
                        $old = Revision::newFromTitle( $this, (int)$old );
                }
                if ( !( $new instanceof Revision ) ) {
                        $new = Revision::newFromTitle( $this, (int)$new );
                }
                if ( !$old || !$new ) {
                        return 0; // nothing to compare
                }
                $dbr = wfGetDB( DB_SLAVE );
                return (int)$dbr->selectField( 'revision', 'count(*)',
                        array(
                                'rev_page' => $this->getArticleId(),
                                'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
                                'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
                        ),
                        __METHOD__
                );
        }

        public function countAuthorsBetween( $old, $new, $limit ) {
                if ( !( $old instanceof Revision ) ) {
                        $old = Revision::newFromTitle( $this, (int)$old );
                }
                if ( !( $new instanceof Revision ) ) {
                        $new = Revision::newFromTitle( $this, (int)$new );
                }
                if ( !$old || !$new ) {
                        return 0; // nothing to compare
                }
                $dbr = wfGetDB( DB_SLAVE );
                $res = $dbr->select( 'revision', 'DISTINCT rev_user_text',
                        array(
                                'rev_page' => $this->getArticleID(),
                                'rev_timestamp > ' . $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) ),
                                'rev_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) )
                        ), __METHOD__,
                        array( 'LIMIT' => $limit + 1 ) // add one so caller knows it was truncated
                );
                return (int)$dbr->numRows( $res );
        }

        public function equals( Title $title ) {
                // Note: === is necessary for proper matching of number-like titles.
                return $this->getInterwiki() === $title->getInterwiki()
                        && $this->getNamespace() == $title->getNamespace()
                        && $this->getDBkey() === $title->getDBkey();
        }

        public function isSubpageOf( Title $title ) {
                return $this->getInterwiki() === $title->getInterwiki()
                        && $this->getNamespace() == $title->getNamespace()
                        && strpos( $this->getDBkey(), $title->getDBkey() . '/' ) === 0;
        }

        public function exists() {
                return $this->getArticleId() != 0;
        }

        public function isAlwaysKnown() {
                if ( $this->mInterwiki != '' ) {
                        return true;  // any interwiki link might be viewable, for all we know
                }
                switch( $this->mNamespace ) {
                        case NS_MEDIA:
                        case NS_FILE:
                                // file exists, possibly in a foreign repo
                                return (bool)wfFindFile( $this );
                        case NS_SPECIAL:
                                // valid special page
                                return SpecialPageFactory::exists( $this->getDBkey() );
                        case NS_MAIN:
                                // selflink, possibly with fragment
                                return $this->mDbkeyform == '';
                        case NS_MEDIAWIKI:
                                // known system message
                                return $this->hasSourceText() !== false;
                        default:
                                return false;
                }
        }

        public function isKnown() {
                return $this->isAlwaysKnown() || $this->exists();
        }

        public function hasSourceText() {
                if ( $this->exists() ) {
                        return true;
                }

                if ( $this->mNamespace == NS_MEDIAWIKI ) {
                        // If the page doesn't exist but is a known system message, default
                        // message content will be displayed, same for language subpages-
                        // Use always content language to avoid loading hundreds of languages
                        // to get the link color.
                        global $wgContLang;
                        list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
                        $message = wfMessage( $name )->inLanguage( $wgContLang )->useDatabase( false );
                        return $message->exists();
                }

                return false;
        }

        public function getDefaultMessageText() {
                global $wgContLang;

                if ( $this->getNamespace() != NS_MEDIAWIKI ) { // Just in case
                        return false;
                }

                list( $name, $lang ) = MessageCache::singleton()->figureMessage( $wgContLang->lcfirst( $this->getText() ) );
                $message = wfMessage( $name )->inLanguage( $lang )->useDatabase( false );

                if ( $message->exists() ) {
                        return $message->plain();
                } else {
                        return false;
                }
        }

        public function invalidateCache() {
                if ( wfReadOnly() ) {
                        return false;
                }
                $dbw = wfGetDB( DB_MASTER );
                $success = $dbw->update(
                        'page',
                        array( 'page_touched' => $dbw->timestamp() ),
                        $this->pageCond(),
                        __METHOD__
                );
                HTMLFileCache::clearFileCache( $this );
                return $success;
        }

        public function touchLinks() {
                $u = new HTMLCacheUpdate( $this, 'pagelinks' );
                $u->doUpdate();

                if ( $this->getNamespace() == NS_CATEGORY ) {
                        $u = new HTMLCacheUpdate( $this, 'categorylinks' );
                        $u->doUpdate();
                }
        }

        public function getTouched( $db = null ) {
                $db = isset( $db ) ? $db : wfGetDB( DB_SLAVE );
                $touched = $db->selectField( 'page', 'page_touched', $this->pageCond(), __METHOD__ );
                return $touched;
        }

        public function getNotificationTimestamp( $user = null ) {
                global $wgUser, $wgShowUpdatedMarker;
                // Assume current user if none given
                if ( !$user ) {
                        $user = $wgUser;
                }
                // Check cache first
                $uid = $user->getId();
                // avoid isset here, as it'll return false for null entries
                if ( array_key_exists( $uid, $this->mNotificationTimestamp ) ) {
                        return $this->mNotificationTimestamp[$uid];
                }
                if ( !$uid || !$wgShowUpdatedMarker ) {
                        return $this->mNotificationTimestamp[$uid] = false;
                }
                // Don't cache too much!
                if ( count( $this->mNotificationTimestamp ) >= self::CACHE_MAX ) {
                        $this->mNotificationTimestamp = array();
                }
                $dbr = wfGetDB( DB_SLAVE );
                $this->mNotificationTimestamp[$uid] = $dbr->selectField( 'watchlist',
                        'wl_notificationtimestamp',
                        array( 'wl_namespace' => $this->getNamespace(),
                                'wl_title' => $this->getDBkey(),
                                'wl_user' => $user->getId()
                        ),
                        __METHOD__
                );
                return $this->mNotificationTimestamp[$uid];
        }

        public function getNamespaceKey( $prepend = 'nstab-' ) {
                global $wgContLang;
                // Gets the subject namespace if this title
                $namespace = MWNamespace::getSubject( $this->getNamespace() );
                // Checks if cononical namespace name exists for namespace
                if ( MWNamespace::exists( $this->getNamespace() ) ) {
                        // Uses canonical namespace name
                        $namespaceKey = MWNamespace::getCanonicalName( $namespace );
                } else {
                        // Uses text of namespace
                        $namespaceKey = $this->getSubjectNsText();
                }
                // Makes namespace key lowercase
                $namespaceKey = $wgContLang->lc( $namespaceKey );
                // Uses main
                if ( $namespaceKey == '' ) {
                        $namespaceKey = 'main';
                }
                // Changes file to image for backwards compatibility
                if ( $namespaceKey == 'file' ) {
                        $namespaceKey = 'image';
                }
                return $prepend . $namespaceKey;
        }

        public function getRedirectsHere( $ns = null ) {
                $redirs = array();

                $dbr = wfGetDB( DB_SLAVE );
                $where = array(
                        'rd_namespace' => $this->getNamespace(),
                        'rd_title' => $this->getDBkey(),
                        'rd_from = page_id'
                );
                if ( !is_null( $ns ) ) {
                        $where['page_namespace'] = $ns;
                }

                $res = $dbr->select(
                        array( 'redirect', 'page' ),
                        array( 'page_namespace', 'page_title' ),
                        $where,
                        __METHOD__
                );

                foreach ( $res as $row ) {
                        $redirs[] = self::newFromRow( $row );
                }
                return $redirs;
        }

        public function isValidRedirectTarget() {
                global $wgInvalidRedirectTargets;

                // invalid redirect targets are stored in a global array, but explicity disallow Userlogout here
                if ( $this->isSpecial( 'Userlogout' ) ) {
                        return false;
                }

                foreach ( $wgInvalidRedirectTargets as $target ) {
                        if ( $this->isSpecial( $target ) ) {
                                return false;
                        }
                }

                return true;
        }

        function getBacklinkCache() {
                if ( is_null( $this->mBacklinkCache ) ) {
                        $this->mBacklinkCache = new BacklinkCache( $this );
                }
                return $this->mBacklinkCache;
        }

        public function canUseNoindex() {
                global $wgContentNamespaces, $wgExemptFromUserRobotsControl;

                $bannedNamespaces = is_null( $wgExemptFromUserRobotsControl )
                        ? $wgContentNamespaces
                        : $wgExemptFromUserRobotsControl;

                return !in_array( $this->mNamespace, $bannedNamespaces );

        }

        public function getCategorySortkey( $prefix = '' ) {
                $unprefixed = $this->getText();

                // Anything that uses this hook should only depend
                // on the Title object passed in, and should probably
                // tell the users to run updateCollations.php --force
                // in order to re-sort existing category relations.
                wfRunHooks( 'GetDefaultSortkey', array( $this, &$unprefixed ) );
                if ( $prefix !== '' ) {
                        # Separate with a line feed, so the unprefixed part is only used as
                        # a tiebreaker when two pages have the exact same prefix.
                        # In UCA, tab is the only character that can sort above LF
                        # so we strip both of them from the original prefix.
                        $prefix = strtr( $prefix, "\n\t", '  ' );
                        return "$prefix\n$unprefixed";
                }
                return $unprefixed;
        }

        public function getPageLanguage() {
                global $wgLang;
                if ( $this->isSpecialPage() ) {
                        // special pages are in the user language
                        return $wgLang;
                } elseif ( $this->isCssOrJsPage() ) {
                        // css/js should always be LTR and is, in fact, English
                        return wfGetLangObj( 'en' );
                } elseif ( $this->getNamespace() == NS_MEDIAWIKI ) {
                        // Parse mediawiki messages with correct target language
                        list( /* $unused */, $lang ) = MessageCache::singleton()->figureMessage( $this->getText() );
                        return wfGetLangObj( $lang );
                }
                global $wgContLang;
                // If nothing special, it should be in the wiki content language
                $pageLang = $wgContLang;
                // Hook at the end because we don't want to override the above stuff
                wfRunHooks( 'PageContentLanguage', array( $this, &$pageLang, $wgLang ) );
                return wfGetLangObj( $pageLang );
        }
}