Apply $wgMaxArticleSize more exactly

[mediawiki.git] / includes / specialpage / SpecialPageFactory.php

<?php
/**
 * Factory for handling the special page list and generating SpecialPage objects.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup SpecialPage
 * @defgroup SpecialPage SpecialPage
 */
use MediaWiki\Linker\LinkRenderer;

/**
 * Factory for handling the special page list and generating SpecialPage objects.
 *
 * To add a special page in an extension, add to $wgSpecialPages either
 * an object instance or an array containing the name and constructor
 * parameters. The latter is preferred for performance reasons.
 *
 * The object instantiated must be either an instance of SpecialPage or a
 * sub-class thereof. It must have an execute() method, which sends the HTML
 * for the special page to $wgOut. The parent class has an execute() method
 * which distributes the call to the historical global functions. Additionally,
 * execute() also checks if the user has the necessary access privileges
 * and bails out if not.
 *
 * To add a core special page, use the similar static list in
 * SpecialPageFactory::$list. To remove a core static special page at runtime, use
 * a SpecialPage_initList hook.
 *
 * @ingroup SpecialPage
 * @since 1.17
 */
class SpecialPageFactory {
        /**
         * List of special page names to the subclass of SpecialPage which handles them.
         */
        private static $coreList = [
                // Maintenance Reports
                'BrokenRedirects' => 'BrokenRedirectsPage',
                'Deadendpages' => 'DeadendPagesPage',
                'DoubleRedirects' => 'DoubleRedirectsPage',
                'Longpages' => 'LongPagesPage',
                'Ancientpages' => 'AncientPagesPage',
                'Lonelypages' => 'LonelyPagesPage',
                'Fewestrevisions' => 'FewestrevisionsPage',
                'Withoutinterwiki' => 'WithoutInterwikiPage',
                'Protectedpages' => 'SpecialProtectedpages',
                'Protectedtitles' => 'SpecialProtectedtitles',
                'Shortpages' => 'ShortPagesPage',
                'Uncategorizedcategories' => 'UncategorizedCategoriesPage',
                'Uncategorizedimages' => 'UncategorizedImagesPage',
                'Uncategorizedpages' => 'UncategorizedPagesPage',
                'Uncategorizedtemplates' => 'UncategorizedTemplatesPage',
                'Unusedcategories' => 'UnusedCategoriesPage',
                'Unusedimages' => 'UnusedimagesPage',
                'Unusedtemplates' => 'UnusedtemplatesPage',
                'Unwatchedpages' => 'UnwatchedpagesPage',
                'Wantedcategories' => 'WantedCategoriesPage',
                'Wantedfiles' => 'WantedFilesPage',
                'Wantedpages' => 'WantedPagesPage',
                'Wantedtemplates' => 'WantedTemplatesPage',

                // List of pages
                'Allpages' => 'SpecialAllPages',
                'Prefixindex' => 'SpecialPrefixindex',
                'Categories' => 'SpecialCategories',
                'Listredirects' => 'ListredirectsPage',
                'PagesWithProp' => 'SpecialPagesWithProp',
                'TrackingCategories' => 'SpecialTrackingCategories',

                // Authentication
                'Userlogin' => 'SpecialUserLogin',
                'Userlogout' => 'SpecialUserlogoutPreAuthManager',
                'CreateAccount' => 'SpecialCreateAccountPreAuthManager',
                'LinkAccounts' => 'SpecialLinkAccounts',
                'UnlinkAccounts' => 'SpecialUnlinkAccounts',
                'ChangeCredentials' => 'SpecialChangeCredentials',
                'RemoveCredentials' => 'SpecialRemoveCredentials',

                // Users and rights
                'Activeusers' => 'SpecialActiveUsers',
                'Block' => 'SpecialBlock',
                'Unblock' => 'SpecialUnblock',
                'BlockList' => 'SpecialBlockList',
                'ChangePassword' => 'SpecialChangePasswordPreAuthManager',
                'BotPasswords' => 'SpecialBotPasswords',
                'PasswordReset' => 'SpecialPasswordResetPreAuthManager',
                'DeletedContributions' => 'DeletedContributionsPage',
                'Preferences' => 'SpecialPreferences',
                'ResetTokens' => 'SpecialResetTokens',
                'Contributions' => 'SpecialContributions',
                'Listgrouprights' => 'SpecialListGroupRights',
                'Listgrants' => 'SpecialListGrants',
                'Listusers' => 'SpecialListUsers',
                'Listadmins' => 'SpecialListAdmins',
                'Listbots' => 'SpecialListBots',
                'Userrights' => 'UserrightsPage',
                'EditWatchlist' => 'SpecialEditWatchlist',

                // Recent changes and logs
                'Newimages' => 'SpecialNewFiles',
                'Log' => 'SpecialLog',
                'Watchlist' => 'SpecialWatchlist',
                'Newpages' => 'SpecialNewpages',
                'Recentchanges' => 'SpecialRecentChanges',
                'Recentchangeslinked' => 'SpecialRecentChangesLinked',
                'Tags' => 'SpecialTags',

                // Media reports and uploads
                'Listfiles' => 'SpecialListFiles',
                'Filepath' => 'SpecialFilepath',
                'MediaStatistics' => 'MediaStatisticsPage',
                'MIMEsearch' => 'MIMEsearchPage',
                'FileDuplicateSearch' => 'FileDuplicateSearchPage',
                'Upload' => 'SpecialUpload',
                'UploadStash' => 'SpecialUploadStash',
                'ListDuplicatedFiles' => 'ListDuplicatedFilesPage',

                // Data and tools
                'ApiSandbox' => 'SpecialApiSandbox',
                'Statistics' => 'SpecialStatistics',
                'Allmessages' => 'SpecialAllMessages',
                'Version' => 'SpecialVersion',
                'Lockdb' => 'SpecialLockdb',
                'Unlockdb' => 'SpecialUnlockdb',

                // Redirecting special pages
                'LinkSearch' => 'LinkSearchPage',
                'Randompage' => 'RandomPage',
                'RandomInCategory' => 'SpecialRandomInCategory',
                'Randomredirect' => 'SpecialRandomredirect',
                'Randomrootpage' => 'SpecialRandomrootpage',

                // High use pages
                'Mostlinkedcategories' => 'MostlinkedCategoriesPage',
                'Mostimages' => 'MostimagesPage',
                'Mostinterwikis' => 'MostinterwikisPage',
                'Mostlinked' => 'MostlinkedPage',
                'Mostlinkedtemplates' => 'MostlinkedTemplatesPage',
                'Mostcategories' => 'MostcategoriesPage',
                'Mostrevisions' => 'MostrevisionsPage',

                // Page tools
                'ComparePages' => 'SpecialComparePages',
                'Export' => 'SpecialExport',
                'Import' => 'SpecialImport',
                'Undelete' => 'SpecialUndelete',
                'Whatlinkshere' => 'SpecialWhatLinksHere',
                'MergeHistory' => 'SpecialMergeHistory',
                'ExpandTemplates' => 'SpecialExpandTemplates',

                // Other
                'Booksources' => 'SpecialBookSources',

                // Unlisted / redirects
                'ApiHelp' => 'SpecialApiHelp',
                'Blankpage' => 'SpecialBlankpage',
                'Diff' => 'SpecialDiff',
                'EditTags' => 'SpecialEditTags',
                'Emailuser' => 'SpecialEmailUser',
                'Movepage' => 'MovePageForm',
                'Mycontributions' => 'SpecialMycontributions',
                'MyLanguage' => 'SpecialMyLanguage',
                'Mypage' => 'SpecialMypage',
                'Mytalk' => 'SpecialMytalk',
                'Myuploads' => 'SpecialMyuploads',
                'AllMyUploads' => 'SpecialAllMyUploads',
                'PermanentLink' => 'SpecialPermanentLink',
                'Redirect' => 'SpecialRedirect',
                'Revisiondelete' => 'SpecialRevisionDelete',
                'RunJobs' => 'SpecialRunJobs',
                'Specialpages' => 'SpecialSpecialpages',
        ];

        private static $list;
        private static $aliases;
        private static $pageObjectCache = [];

        /**
         * Reset the internal list of special pages. Useful when changing $wgSpecialPages after
         * the internal list has already been initialized, e.g. during testing.
         */
        public static function resetList() {
                self::$list = null;
                self::$aliases = null;
                self::$pageObjectCache = [];
        }

        /**
         * Returns a list of canonical special page names.
         * May be used to iterate over all registered special pages.
         *
         * @return string[]
         */
        public static function getNames() {
                return array_keys( self::getPageList() );
        }

        /**
         * Get the special page list as an array
         *
         * @deprecated since 1.24, use getNames() instead.
         * @return array
         */
        public static function getList() {
                wfDeprecated( __FUNCTION__, '1.24' );
                return self::getPageList();
        }

        /**
         * Get the special page list as an array
         *
         * @return array
         */
        private static function getPageList() {
                global $wgSpecialPages;
                global $wgDisableInternalSearch, $wgEmailAuthentication;
                global $wgEnableEmail, $wgEnableJavaScriptTest;
                global $wgPageLanguageUseDB, $wgContentHandlerUseDB;
                global $wgDisableAuthManager;

                if ( !is_array( self::$list ) ) {

                        self::$list = self::$coreList;

                        if ( !$wgDisableInternalSearch ) {
                                self::$list['Search'] = 'SpecialSearch';
                        }

                        if ( $wgEmailAuthentication ) {
                                self::$list['Confirmemail'] = 'EmailConfirmation';
                                self::$list['Invalidateemail'] = 'EmailInvalidation';
                        }

                        if ( $wgEnableEmail ) {
                                self::$list['ChangeEmail'] = 'SpecialChangeEmailPreAuthManager';
                        }

                        if ( $wgEnableJavaScriptTest ) {
                                self::$list['JavaScriptTest'] = 'SpecialJavaScriptTest';
                        }

                        if ( $wgPageLanguageUseDB ) {
                                self::$list['PageLanguage'] = 'SpecialPageLanguage';
                        }
                        if ( $wgContentHandlerUseDB ) {
                                self::$list['ChangeContentModel'] = 'SpecialChangeContentModel';
                        }

                        // horrible hack to allow selection between old and new classes via a feature flag - T110756
                        // will be removed once AuthManager is stable
                        if ( !$wgDisableAuthManager ) {
                                self::$list = array_map( function ( $class ) {
                                        return preg_replace( '/PreAuthManager$/', '', $class );
                                }, self::$list );
                                self::$list['Userlogout'] = 'SpecialUserLogout'; // case matters
                        } else {
                                self::$list['Userlogin'] = 'LoginForm';
                                self::$list = array_diff_key( self::$list, array_fill_keys( [
                                        'LinkAccounts', 'UnlinkAccounts', 'ChangeCredentials', 'RemoveCredentials',
                                ], true ) );
                        }

                        // Add extension special pages
                        self::$list = array_merge( self::$list, $wgSpecialPages );

                        // This hook can be used to disable unwanted core special pages
                        // or conditionally register special pages.
                        Hooks::run( 'SpecialPage_initList', [ &self::$list ] );

                }

                return self::$list;
        }

        /**
         * Initialise and return the list of special page aliases. Returns an array where
         * the key is an alias, and the value is the canonical name of the special page.
         * All registered special pages are guaranteed to map to themselves.
         * @return array
         */
        private static function getAliasList() {
                if ( is_null( self::$aliases ) ) {
                        global $wgContLang;
                        $aliases = $wgContLang->getSpecialPageAliases();
                        $pageList = self::getPageList();

                        self::$aliases = [];
                        $keepAlias = [];

                        // Force every canonical name to be an alias for itself.
                        foreach ( $pageList as $name => $stuff ) {
                                $caseFoldedAlias = $wgContLang->caseFold( $name );
                                self::$aliases[$caseFoldedAlias] = $name;
                                $keepAlias[$caseFoldedAlias] = 'canonical';
                        }

                        // Check for $aliases being an array since Language::getSpecialPageAliases can return null
                        if ( is_array( $aliases ) ) {
                                foreach ( $aliases as $realName => $aliasList ) {
                                        $aliasList = array_values( $aliasList );
                                        foreach ( $aliasList as $i => $alias ) {
                                                $caseFoldedAlias = $wgContLang->caseFold( $alias );

                                                if ( isset( self::$aliases[$caseFoldedAlias] ) &&
                                                        $realName === self::$aliases[$caseFoldedAlias]
                                                ) {
                                                        // Ignore same-realName conflicts
                                                        continue;
                                                }

                                                if ( !isset( $keepAlias[$caseFoldedAlias] ) ) {
                                                        self::$aliases[$caseFoldedAlias] = $realName;
                                                        if ( !$i ) {
                                                                $keepAlias[$caseFoldedAlias] = 'first';
                                                        }
                                                } elseif ( !$i ) {
                                                        wfWarn( "First alias '$alias' for $realName conflicts with " .
                                                                "{$keepAlias[$caseFoldedAlias]} alias for " .
                                                                self::$aliases[$caseFoldedAlias]
                                                        );
                                                }
                                        }
                                }
                        }
                }

                return self::$aliases;
        }

        /**
         * Given a special page name with a possible subpage, return an array
         * where the first element is the special page name and the second is the
         * subpage.
         *
         * @param string $alias
         * @return array Array( String, String|null ), or array( null, null ) if the page is invalid
         */
        public static function resolveAlias( $alias ) {
                global $wgContLang;
                $bits = explode( '/', $alias, 2 );

                $caseFoldedAlias = $wgContLang->caseFold( $bits[0] );
                $caseFoldedAlias = str_replace( ' ', '_', $caseFoldedAlias );
                $aliases = self::getAliasList();
                if ( isset( $aliases[$caseFoldedAlias] ) ) {
                        $name = $aliases[$caseFoldedAlias];
                } else {
                        return [ null, null ];
                }

                if ( !isset( $bits[1] ) ) { // bug 2087
                        $par = null;
                } else {
                        $par = $bits[1];
                }

                return [ $name, $par ];
        }

        /**
         * Check if a given name exist as a special page or as a special page alias
         *
         * @param string $name Name of a special page
         * @return bool True if a special page exists with this name
         */
        public static function exists( $name ) {
                list( $title, /*...*/ ) = self::resolveAlias( $name );

                $specialPageList = self::getPageList();
                return isset( $specialPageList[$title] );
        }

        /**
         * Find the object with a given name and return it (or NULL)
         *
         * @param string $name Special page name, may be localised and/or an alias
         * @return SpecialPage|null SpecialPage object or null if the page doesn't exist
         */
        public static function getPage( $name ) {
                list( $realName, /*...*/ ) = self::resolveAlias( $name );

                if ( isset( self::$pageObjectCache[$realName] ) ) {
                        return self::$pageObjectCache[$realName];
                }

                $specialPageList = self::getPageList();

                if ( isset( $specialPageList[$realName] ) ) {
                        $rec = $specialPageList[$realName];

                        if ( is_callable( $rec ) ) {
                                // Use callback to instantiate the special page
                                $page = call_user_func( $rec );
                        } elseif ( is_string( $rec ) ) {
                                $className = $rec;
                                $page = new $className;
                        } elseif ( is_array( $rec ) ) {
                                $className = array_shift( $rec );
                                // @deprecated, officially since 1.18, unofficially since forever
                                wfDeprecated( "Array syntax for \$wgSpecialPages is deprecated ($className), " .
                                        "define a subclass of SpecialPage instead.", '1.18' );
                                $page = ObjectFactory::getObjectFromSpec( [
                                        'class' => $className,
                                        'args' => $rec,
                                        'closure_expansion' => false,
                                ] );
                        } elseif ( $rec instanceof SpecialPage ) {
                                $page = $rec; // XXX: we should deep clone here
                        } else {
                                $page = null;
                        }

                        self::$pageObjectCache[$realName] = $page;
                        if ( $page instanceof SpecialPage ) {
                                return $page;
                        } else {
                                // It's not a classname, nor a callback, nor a legacy constructor array,
                                // nor a special page object. Give up.
                                wfLogWarning( "Cannot instantiate special page $realName: bad spec!" );
                                return null;
                        }

                } else {
                        return null;
                }
        }

        /**
         * Return categorised listable special pages which are available
         * for the current user, and everyone.
         *
         * @param User $user User object to check permissions, $wgUser will be used
         *        if not provided
         * @return array ( string => Specialpage )
         */
        public static function getUsablePages( User $user = null ) {
                $pages = [];
                if ( $user === null ) {
                        global $wgUser;
                        $user = $wgUser;
                }
                foreach ( self::getPageList() as $name => $rec ) {
                        $page = self::getPage( $name );
                        if ( $page ) { // not null
                                $page->setContext( RequestContext::getMain() );
                                if ( $page->isListed()
                                        && ( !$page->isRestricted() || $page->userCanExecute( $user ) )
                                ) {
                                        $pages[$name] = $page;
                                }
                        }
                }

                return $pages;
        }

        /**
         * Return categorised listable special pages for all users
         *
         * @return array ( string => Specialpage )
         */
        public static function getRegularPages() {
                $pages = [];
                foreach ( self::getPageList() as $name => $rec ) {
                        $page = self::getPage( $name );
                        if ( $page->isListed() && !$page->isRestricted() ) {
                                $pages[$name] = $page;
                        }
                }

                return $pages;
        }

        /**
         * Return categorised listable special pages which are available
         * for the current user, but not for everyone
         *
         * @param User|null $user User object to use or null for $wgUser
         * @return array ( string => Specialpage )
         */
        public static function getRestrictedPages( User $user = null ) {
                $pages = [];
                if ( $user === null ) {
                        global $wgUser;
                        $user = $wgUser;
                }
                foreach ( self::getPageList() as $name => $rec ) {
                        $page = self::getPage( $name );
                        if (
                                $page->isListed()
                                && $page->isRestricted()
                                && $page->userCanExecute( $user )
                        ) {
                                $pages[$name] = $page;
                        }
                }

                return $pages;
        }

        /**
         * Execute a special page path.
         * The path may contain parameters, e.g. Special:Name/Params
         * Extracts the special page name and call the execute method, passing the parameters
         *
         * Returns a title object if the page is redirected, false if there was no such special
         * page, and true if it was successful.
         *
         * @param Title $title
         * @param IContextSource $context
         * @param bool $including Bool output is being captured for use in {{special:whatever}}
         * @param LinkRenderer|null $linkRenderer (since 1.28)
         *
         * @return bool
         */
        public static function executePath( Title &$title, IContextSource &$context, $including = false,
                LinkRenderer $linkRenderer = null
        ) {
                // @todo FIXME: Redirects broken due to this call
                $bits = explode( '/', $title->getDBkey(), 2 );
                $name = $bits[0];
                if ( !isset( $bits[1] ) ) { // bug 2087
                        $par = null;
                } else {
                        $par = $bits[1];
                }

                $page = self::getPage( $name );
                if ( !$page ) {
                        $context->getOutput()->setArticleRelated( false );
                        $context->getOutput()->setRobotPolicy( 'noindex,nofollow' );

                        global $wgSend404Code;
                        if ( $wgSend404Code ) {
                                $context->getOutput()->setStatusCode( 404 );
                        }

                        $context->getOutput()->showErrorPage( 'nosuchspecialpage', 'nospecialpagetext' );

                        return false;
                }

                if ( !$including ) {
                        // Narrow DB query expectations for this HTTP request
                        $trxLimits = $context->getConfig()->get( 'TrxProfilerLimits' );
                        $trxProfiler = Profiler::instance()->getTransactionProfiler();
                        if ( $context->getRequest()->wasPosted() && !$page->doesWrites() ) {
                                $trxProfiler->setExpectations( $trxLimits['POST-nonwrite'], __METHOD__ );
                                $context->getRequest()->markAsSafeRequest();
                        }
                }

                // Page exists, set the context
                $page->setContext( $context );

                if ( !$including ) {
                        // Redirect to canonical alias for GET commands
                        // Not for POST, we'd lose the post data, so it's best to just distribute
                        // the request. Such POST requests are possible for old extensions that
                        // generate self-links without being aware that their default name has
                        // changed.
                        if ( $name != $page->getLocalName() && !$context->getRequest()->wasPosted() ) {
                                $query = $context->getRequest()->getQueryValues();
                                unset( $query['title'] );
                                $title = $page->getPageTitle( $par );
                                $url = $title->getFullURL( $query );
                                $context->getOutput()->redirect( $url );

                                return $title;
                        } else {
                                $context->setTitle( $page->getPageTitle( $par ) );
                        }
                } elseif ( !$page->isIncludable() ) {
                        return false;
                }

                $page->including( $including );
                if ( $linkRenderer ) {
                        $page->setLinkRenderer( $linkRenderer );
                }

                // Execute special page
                $page->run( $par );

                return true;
        }

        /**
         * Just like executePath() but will override global variables and execute
         * the page in "inclusion" mode. Returns true if the execution was
         * successful or false if there was no such special page, or a title object
         * if it was a redirect.
         *
         * Also saves the current $wgTitle, $wgOut, $wgRequest, $wgUser and $wgLang
         * variables so that the special page will get the context it'd expect on a
         * normal request, and then restores them to their previous values after.
         *
         * @param Title $title
         * @param IContextSource $context
         * @param LinkRenderer|null $linkRenderer (since 1.28)
         * @return string HTML fragment
         */
        public static function capturePath(
                Title $title, IContextSource $context, LinkRenderer $linkRenderer = null
        ) {
                global $wgTitle, $wgOut, $wgRequest, $wgUser, $wgLang;
                $main = RequestContext::getMain();

                // Save current globals and main context
                $glob = [
                        'title' => $wgTitle,
                        'output' => $wgOut,
                        'request' => $wgRequest,
                        'user' => $wgUser,
                        'language' => $wgLang,
                ];
                $ctx = [
                        'title' => $main->getTitle(),
                        'output' => $main->getOutput(),
                        'request' => $main->getRequest(),
                        'user' => $main->getUser(),
                        'language' => $main->getLanguage(),
                ];

                // Override
                $wgTitle = $title;
                $wgOut = $context->getOutput();
                $wgRequest = $context->getRequest();
                $wgUser = $context->getUser();
                $wgLang = $context->getLanguage();
                $main->setTitle( $title );
                $main->setOutput( $context->getOutput() );
                $main->setRequest( $context->getRequest() );
                $main->setUser( $context->getUser() );
                $main->setLanguage( $context->getLanguage() );

                // The useful part
                $ret = self::executePath( $title, $context, true, $linkRenderer );

                // Restore old globals and context
                $wgTitle = $glob['title'];
                $wgOut = $glob['output'];
                $wgRequest = $glob['request'];
                $wgUser = $glob['user'];
                $wgLang = $glob['language'];
                $main->setTitle( $ctx['title'] );
                $main->setOutput( $ctx['output'] );
                $main->setRequest( $ctx['request'] );
                $main->setUser( $ctx['user'] );
                $main->setLanguage( $ctx['language'] );

                return $ret;
        }

        /**
         * Get the local name for a specified canonical name
         *
         * @param string $name
         * @param string|bool $subpage
         * @return string
         */
        public static function getLocalNameFor( $name, $subpage = false ) {
                global $wgContLang;
                $aliases = $wgContLang->getSpecialPageAliases();
                $aliasList = self::getAliasList();

                // Find the first alias that maps back to $name
                if ( isset( $aliases[$name] ) ) {
                        $found = false;
                        foreach ( $aliases[$name] as $alias ) {
                                $caseFoldedAlias = $wgContLang->caseFold( $alias );
                                $caseFoldedAlias = str_replace( ' ', '_', $caseFoldedAlias );
                                if ( isset( $aliasList[$caseFoldedAlias] ) &&
                                        $aliasList[$caseFoldedAlias] === $name
                                ) {
                                        $name = $alias;
                                        $found = true;
                                        break;
                                }
                        }
                        if ( !$found ) {
                                wfWarn( "Did not find a usable alias for special page '$name'. " .
                                        "It seems all defined aliases conflict?" );
                        }
                } else {
                        // Check if someone misspelled the correct casing
                        if ( is_array( $aliases ) ) {
                                foreach ( $aliases as $n => $values ) {
                                        if ( strcasecmp( $name, $n ) === 0 ) {
                                                wfWarn( "Found alias defined for $n when searching for " .
                                                        "special page aliases for $name. Case mismatch?" );
                                                return self::getLocalNameFor( $n, $subpage );
                                        }
                                }
                        }

                        wfWarn( "Did not find alias for special page '$name'. " .
                                "Perhaps no aliases are defined for it?" );
                }

                if ( $subpage !== false && !is_null( $subpage ) ) {
                        $name = "$name/$subpage";
                }

                return $wgContLang->ucfirst( $name );
        }

        /**
         * Get a title for a given alias
         *
         * @param string $alias
         * @return Title|null Title or null if there is no such alias
         */
        public static function getTitleForAlias( $alias ) {
                list( $name, $subpage ) = self::resolveAlias( $alias );
                if ( $name != null ) {
                        return SpecialPage::getTitleFor( $name, $subpage );
                } else {
                        return null;
                }
        }
}