Merge "Whitelist the <wbr> element."

[mediawiki.git] / includes / SpecialPage.php

<?php
/**
 * Parent class for all special pages.
 *
 * 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
 */

/**
 * Parent special page class, also static functions for handling the special
 * page list.
 * @ingroup SpecialPage
 */
class SpecialPage {
        // The canonical name of this special page
        // Also used for the default <h1> heading, @see getDescription()
        protected $mName;

        // The local name of this special page
        private $mLocalName;

        // Minimum user level required to access this page, or "" for anyone.
        // Also used to categorise the pages in Special:Specialpages
        private $mRestriction;

        // Listed in Special:Specialpages?
        private $mListed;

        // Function name called by the default execute()
        private $mFunction;

        // File which needs to be included before the function above can be called
        private $mFile;

        // Whether or not this special page is being included from an article
        protected $mIncluding;

        // Whether the special page can be included in an article
        protected $mIncludable;

        /**
         * Current request context
         * @var IContextSource
         */
        protected $mContext;

        /**
         * Initialise the special page list
         * This must be called before accessing SpecialPage::$mList
         * @deprecated since 1.18
         */
        static function initList() {
                wfDeprecated( __METHOD__, '1.18' );
                // Noop
        }

        /**
         * @deprecated since 1.18
         */
        static function initAliasList() {
                wfDeprecated( __METHOD__, '1.18' );
                // Noop
        }

        /**
         * Given a special page alias, return the special page name.
         * Returns false if there is no such alias.
         *
         * @param $alias String
         * @return String or false
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function resolveAlias( $alias ) {
                wfDeprecated( __METHOD__, '1.18' );
                list( $name, /*...*/ ) = SpecialPageFactory::resolveAlias( $alias );
                return $name;
        }

        /**
         * 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 $alias String
         * @return Array
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function resolveAliasWithSubpage( $alias ) {
                return SpecialPageFactory::resolveAlias( $alias );
        }

        /**
         * Add a page to a certain display group for Special:SpecialPages
         *
         * @param $page Mixed: SpecialPage or string
         * @param $group String
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function setGroup( $page, $group ) {
                wfDeprecated( __METHOD__, '1.18' );
                SpecialPageFactory::setGroup( $page, $group );
        }

        /**
         * Get the group that the special page belongs in on Special:SpecialPage
         *
         * @param $page SpecialPage
         * @return string
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function getGroup( &$page ) {
                wfDeprecated( __METHOD__, '1.18' );
                return SpecialPageFactory::getGroup( $page );
        }

        /**
         * Remove a special page from the list
         * Formerly used to disable expensive or dangerous special pages. The
         * preferred method is now to add a SpecialPage_initList hook.
         * @deprecated since 1.18
         *
         * @param string $name the page to remove
         */
        static function removePage( $name ) {
                wfDeprecated( __METHOD__, '1.18' );
                unset( SpecialPageFactory::getList()->$name );
        }

        /**
         * 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 Boolean: true if a special page exists with this name
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function exists( $name ) {
                wfDeprecated( __METHOD__, '1.18' );
                return SpecialPageFactory::exists( $name );
        }

        /**
         * Find the object with a given name and return it (or NULL)
         *
         * @param $name String
         * @return SpecialPage object or null if the page doesn't exist
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function getPage( $name ) {
                wfDeprecated( __METHOD__, '1.18' );
                return SpecialPageFactory::getPage( $name );
        }

        /**
         * Get a special page with a given localised name, or NULL if there
         * is no such special page.
         *
         * @param $alias String
         * @return SpecialPage object or null if the page doesn't exist
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function getPageByAlias( $alias ) {
                wfDeprecated( __METHOD__, '1.18' );
                return SpecialPageFactory::getPage( $alias );
        }

        /**
         * Return categorised listable special pages which are available
         * for the current user, and everyone.
         *
         * @param $user User object to check permissions, $wgUser will be used
         *              if not provided
         * @return array Associative array mapping page's name to its SpecialPage object
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function getUsablePages( User $user = null ) {
                wfDeprecated( __METHOD__, '1.18' );
                return SpecialPageFactory::getUsablePages( $user );
        }

        /**
         * Return categorised listable special pages for all users
         *
         * @return array Associative array mapping page's name to its SpecialPage object
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function getRegularPages() {
                wfDeprecated( __METHOD__, '1.18' );
                return SpecialPageFactory::getRegularPages();
        }

        /**
         * Return categorised listable special pages which are available
         * for the current user, but not for everyone
         *
         * @return array Associative array mapping page's name to its SpecialPage object
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function getRestrictedPages() {
                wfDeprecated( __METHOD__, '1.18' );
                return SpecialPageFactory::getRestrictedPages();
        }

        /**
         * 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 object
         * @param $context        IContextSource
         * @param $including      Bool output is being captured for use in {{special:whatever}}
         * @return Bool
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        public static function executePath( &$title, IContextSource &$context, $including = false ) {
                wfDeprecated( __METHOD__, '1.18' );
                return SpecialPageFactory::executePath( $title, $context, $including );
        }

        /**
         * Get the local name for a specified canonical name
         *
         * @param $name String
         * @param $subpage Mixed: boolean false, or string
         *
         * @return String
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function getLocalNameFor( $name, $subpage = false ) {
                wfDeprecated( __METHOD__, '1.18' );
                return SpecialPageFactory::getLocalNameFor( $name, $subpage );
        }

        /**
         * Get a localised Title object for a specified special page name
         *
         * @param $name String
         * @param string|Bool $subpage subpage string, or false to not use a subpage
         * @param string $fragment the link fragment (after the "#")
         * @throws MWException
         * @return Title object
         */
        public static function getTitleFor( $name, $subpage = false, $fragment = '' ) {
                $name = SpecialPageFactory::getLocalNameFor( $name, $subpage );
                if ( $name ) {
                        return Title::makeTitle( NS_SPECIAL, $name, $fragment );
                } else {
                        throw new MWException( "Invalid special page name \"$name\"" );
                }
        }

        /**
         * Get a localised Title object for a page name with a possibly unvalidated subpage
         *
         * @param $name String
         * @param string|Bool $subpage subpage string, or false to not use a subpage
         * @return Title object or null if the page doesn't exist
         */
        public static function getSafeTitleFor( $name, $subpage = false ) {
                $name = SpecialPageFactory::getLocalNameFor( $name, $subpage );
                if ( $name ) {
                        return Title::makeTitleSafe( NS_SPECIAL, $name );
                } else {
                        return null;
                }
        }

        /**
         * Get a title for a given alias
         *
         * @param $alias String
         * @return Title or null if there is no such alias
         * @deprecated since 1.18 call SpecialPageFactory method directly
         */
        static function getTitleForAlias( $alias ) {
                wfDeprecated( __METHOD__, '1.18' );
                return SpecialPageFactory::getTitleForAlias( $alias );
        }

        /**
         * Default constructor for special pages
         * Derivative classes should call this from their constructor
         *     Note that if the user does not have the required level, an error message will
         *     be displayed by the default execute() method, without the global function ever
         *     being called.
         *
         *     If you override execute(), you can recover the default behavior with userCanExecute()
         *     and displayRestrictionError()
         *
         * @param string $name Name of the special page, as seen in links and URLs
         * @param string $restriction User right required, e.g. "block" or "delete"
         * @param bool $listed Whether the page is listed in Special:Specialpages
         * @param Callback|Bool $function Function called by execute(). By default
         * it is constructed from $name
         * @param string $file File which is included by execute(). It is also
         * constructed from $name by default
         * @param bool $includable Whether the page can be included in normal pages
         */
        public function __construct(
                $name = '', $restriction = '', $listed = true,
                $function = false, $file = 'default', $includable = false
        ) {
                $this->init( $name, $restriction, $listed, $function, $file, $includable );
        }

        /**
         * Do the real work for the constructor, mainly so __call() can intercept
         * calls to SpecialPage()
         * @param string $name Name of the special page, as seen in links and URLs
         * @param string $restriction User right required, e.g. "block" or "delete"
         * @param bool $listed Whether the page is listed in Special:Specialpages
         * @param Callback|Bool $function Function called by execute(). By default
         * it is constructed from $name
         * @param string $file File which is included by execute(). It is also
         * constructed from $name by default
         * @param bool $includable Whether the page can be included in normal pages
         */
        private function init( $name, $restriction, $listed, $function, $file, $includable ) {
                $this->mName = $name;
                $this->mRestriction = $restriction;
                $this->mListed = $listed;
                $this->mIncludable = $includable;
                if ( !$function ) {
                        $this->mFunction = 'wfSpecial' . $name;
                } else {
                        $this->mFunction = $function;
                }
                if ( $file === 'default' ) {
                        $this->mFile = __DIR__ . "/specials/Special$name.php";
                } else {
                        $this->mFile = $file;
                }
        }

        /**
         * Use PHP's magic __call handler to get calls to the old PHP4 constructor
         * because PHP E_STRICT yells at you for having __construct() and SpecialPage()
         *
         * @param string $fName Name of called method
         * @param array $a Arguments to the method
         * @throws MWException
         * @deprecated since 1.17, call parent::__construct()
         */
        public function __call( $fName, $a ) {
                // Deprecated messages now, remove in 1.19 or 1.20?
                wfDeprecated( __METHOD__, '1.17' );

                // Sometimes $fName is SpecialPage, sometimes it's specialpage. <3 PHP
                if ( strtolower( $fName ) == 'specialpage' ) {
                        $name = isset( $a[0] ) ? $a[0] : '';
                        $restriction = isset( $a[1] ) ? $a[1] : '';
                        $listed = isset( $a[2] ) ? $a[2] : true;
                        $function = isset( $a[3] ) ? $a[3] : false;
                        $file = isset( $a[4] ) ? $a[4] : 'default';
                        $includable = isset( $a[5] ) ? $a[5] : false;
                        $this->init( $name, $restriction, $listed, $function, $file, $includable );
                } else {
                        $className = get_class( $this );
                        throw new MWException( "Call to undefined method $className::$fName" );
                }
        }

        /**
         * Get the name of this Special Page.
         * @return String
         */
        function getName() {
                return $this->mName;
        }

        /**
         * Get the permission that a user must have to execute this page
         * @return String
         */
        function getRestriction() {
                return $this->mRestriction;
        }

        /**
         * Get the file which will be included by SpecialPage::execute() if your extension is
         * still stuck in the past and hasn't overridden the execute() method.  No modern code
         * should want or need to know this.
         * @return String
         * @deprecated since 1.18
         */
        function getFile() {
                wfDeprecated( __METHOD__, '1.18' );
                return $this->mFile;
        }

        // @todo FIXME: Decide which syntax to use for this, and stick to it
        /**
         * Whether this special page is listed in Special:SpecialPages
         * @since r3583 (v1.3)
         * @return Bool
         */
        function isListed() {
                return $this->mListed;
        }
        /**
         * Set whether this page is listed in Special:Specialpages, at run-time
         * @since r3583 (v1.3)
         * @param $listed Bool
         * @return Bool
         */
        function setListed( $listed ) {
                return wfSetVar( $this->mListed, $listed );
        }
        /**
         * Get or set whether this special page is listed in Special:SpecialPages
         * @since r11308 (v1.6)
         * @param $x Bool
         * @return Bool
         */
        function listed( $x = null ) {
                return wfSetVar( $this->mListed, $x );
        }

        /**
         * Whether it's allowed to transclude the special page via {{Special:Foo/params}}
         * @return Bool
         */
        public function isIncludable() {
                return $this->mIncludable;
        }

        /**
         * These mutators are very evil, as the relevant variables should not mutate.  So
         * don't use them.
         * @param $x Mixed
         * @return Mixed
         * @deprecated since 1.18
         */
        function name( $x = null ) {
                wfDeprecated( __METHOD__, '1.18' );
                return wfSetVar( $this->mName, $x );
        }

        /**
         * These mutators are very evil, as the relevant variables should not mutate.  So
         * don't use them.
         * @param $x Mixed
         * @return Mixed
         * @deprecated since 1.18
         */
        function restriction( $x = null ) {
                wfDeprecated( __METHOD__, '1.18' );
                return wfSetVar( $this->mRestriction, $x );
        }

        /**
         * These mutators are very evil, as the relevant variables should not mutate.  So
         * don't use them.
         * @param $x Mixed
         * @return Mixed
         * @deprecated since 1.18
         */
        function func( $x = null ) {
                wfDeprecated( __METHOD__, '1.18' );
                return wfSetVar( $this->mFunction, $x );
        }

        /**
         * These mutators are very evil, as the relevant variables should not mutate.  So
         * don't use them.
         * @param $x Mixed
         * @return Mixed
         * @deprecated since 1.18
         */
        function file( $x = null ) {
                wfDeprecated( __METHOD__, '1.18' );
                return wfSetVar( $this->mFile, $x );
        }

        /**
         * These mutators are very evil, as the relevant variables should not mutate.  So
         * don't use them.
         * @param $x Mixed
         * @return Mixed
         * @deprecated since 1.18
         */
        function includable( $x = null ) {
                wfDeprecated( __METHOD__, '1.18' );
                return wfSetVar( $this->mIncludable, $x );
        }

        /**
         * Whether the special page is being evaluated via transclusion
         * @param $x Bool
         * @return Bool
         */
        function including( $x = null ) {
                return wfSetVar( $this->mIncluding, $x );
        }

        /**
         * Get the localised name of the special page
         */
        function getLocalName() {
                if ( !isset( $this->mLocalName ) ) {
                        $this->mLocalName = SpecialPageFactory::getLocalNameFor( $this->mName );
                }
                return $this->mLocalName;
        }

        /**
         * Is this page expensive (for some definition of expensive)?
         * Expensive pages are disabled or cached in miser mode.  Originally used
         * (and still overridden) by QueryPage and subclasses, moved here so that
         * Special:SpecialPages can safely call it for all special pages.
         *
         * @return Boolean
         */
        public function isExpensive() {
                return false;
        }

        /**
         * Is this page cached?
         * Expensive pages are cached or disabled in miser mode.
         * Used by QueryPage and subclasses, moved here so that
         * Special:SpecialPages can safely call it for all special pages.
         *
         * @return Boolean
         * @since 1.21
         */
        public function isCached() {
                return false;
        }

        /**
         * Can be overridden by subclasses with more complicated permissions
         * schemes.
         *
         * @return Boolean: should the page be displayed with the restricted-access
         *   pages?
         */
        public function isRestricted() {
                // DWIM: If anons can do something, then it is not restricted
                return $this->mRestriction != '' && !User::groupHasPermission( '*', $this->mRestriction );
        }

        /**
         * Checks if the given user (identified by an object) can execute this
         * special page (as defined by $mRestriction).  Can be overridden by sub-
         * classes with more complicated permissions schemes.
         *
         * @param $user User: the user to check
         * @return Boolean: does the user have permission to view the page?
         */
        public function userCanExecute( User $user ) {
                return $user->isAllowed( $this->mRestriction );
        }

        /**
         * Output an error message telling the user what access level they have to have
         */
        function displayRestrictionError() {
                throw new PermissionsError( $this->mRestriction );
        }

        /**
         * Checks if userCanExecute, and if not throws a PermissionsError
         *
         * @since 1.19
         */
        public function checkPermissions() {
                if ( !$this->userCanExecute( $this->getUser() ) ) {
                        $this->displayRestrictionError();
                }
        }

        /**
         * If the wiki is currently in readonly mode, throws a ReadOnlyError
         *
         * @since 1.19
         * @throws ReadOnlyError
         */
        public function checkReadOnly() {
                if ( wfReadOnly() ) {
                        throw new ReadOnlyError;
                }
        }

        /**
         * Sets headers - this should be called from the execute() method of all derived classes!
         */
        function setHeaders() {
                $out = $this->getOutput();
                $out->setArticleRelated( false );
                $out->setRobotPolicy( "noindex,nofollow" );
                $out->setPageTitle( $this->getDescription() );
        }

        /**
         * Entry point.
         *
         * @since 1.20
         *
         * @param $subPage string|null
         */
        final public function run( $subPage ) {
                /**
                 * Gets called before @see SpecialPage::execute.
                 *
                 * @since 1.20
                 *
                 * @param $special SpecialPage
                 * @param $subPage string|null
                 */
                wfRunHooks( 'SpecialPageBeforeExecute', array( $this, $subPage ) );

                $this->beforeExecute( $subPage );
                $this->execute( $subPage );
                $this->afterExecute( $subPage );

                /**
                 * Gets called after @see SpecialPage::execute.
                 *
                 * @since 1.20
                 *
                 * @param $special SpecialPage
                 * @param $subPage string|null
                 */
                wfRunHooks( 'SpecialPageAfterExecute', array( $this, $subPage ) );
        }

        /**
         * Gets called before @see SpecialPage::execute.
         *
         * @since 1.20
         *
         * @param $subPage string|null
         */
        protected function beforeExecute( $subPage ) {
                // No-op
        }

        /**
         * Gets called after @see SpecialPage::execute.
         *
         * @since 1.20
         *
         * @param $subPage string|null
         */
        protected function afterExecute( $subPage ) {
                // No-op
        }

        /**
         * Default execute method
         * Checks user permissions, calls the function given in mFunction
         *
         * This must be overridden by subclasses; it will be made abstract in a future version
         *
         * @param $subPage string|null
         */
        public function execute( $subPage ) {
                $this->setHeaders();
                $this->checkPermissions();

                $func = $this->mFunction;
                // only load file if the function does not exist
                if ( !is_callable( $func ) && $this->mFile ) {
                        require_once $this->mFile;
                }
                $this->outputHeader();
                call_user_func( $func, $subPage, $this );
        }

        /**
         * Outputs a summary message on top of special pages
         * Per default the message key is the canonical name of the special page
         * May be overridden, i.e. by extensions to stick with the naming conventions
         * for message keys: 'extensionname-xxx'
         *
         * @param string $summaryMessageKey message key of the summary
         */
        function outputHeader( $summaryMessageKey = '' ) {
                global $wgContLang;

                if ( $summaryMessageKey == '' ) {
                        $msg = $wgContLang->lc( $this->getName() ) . '-summary';
                } else {
                        $msg = $summaryMessageKey;
                }
                if ( !$this->msg( $msg )->isDisabled() && !$this->including() ) {
                        $this->getOutput()->wrapWikiMsg(
                                "<div class='mw-specialpage-summary'>\n$1\n</div>", $msg );
                }

        }

        /**
         * Returns the name that goes in the \<h1\> in the special page itself, and
         * also the name that will be listed in Special:Specialpages
         *
         * Derived classes can override this, but usually it is easier to keep the
         * default behavior. Messages can be added at run-time, see
         * MessageCache.php.
         *
         * @return String
         */
        function getDescription() {
                return $this->msg( strtolower( $this->mName ) )->text();
        }

        /**
         * Get a self-referential title object
         *
         * @param $subpage String|Bool
         * @return Title object
         */
        function getTitle( $subpage = false ) {
                return self::getTitleFor( $this->mName, $subpage );
        }

        /**
         * Sets the context this SpecialPage is executed in
         *
         * @param $context IContextSource
         * @since 1.18
         */
        public function setContext( $context ) {
                $this->mContext = $context;
        }

        /**
         * Gets the context this SpecialPage is executed in
         *
         * @return IContextSource|RequestContext
         * @since 1.18
         */
        public function getContext() {
                if ( $this->mContext instanceof IContextSource ) {
                        return $this->mContext;
                } else {
                        wfDebug( __METHOD__ . " called and \$mContext is null. " .
                                "Return RequestContext::getMain(); for sanity\n" );
                        return RequestContext::getMain();
                }
        }

        /**
         * Get the WebRequest being used for this instance
         *
         * @return WebRequest
         * @since 1.18
         */
        public function getRequest() {
                return $this->getContext()->getRequest();
        }

        /**
         * Get the OutputPage being used for this instance
         *
         * @return OutputPage
         * @since 1.18
         */
        public function getOutput() {
                return $this->getContext()->getOutput();
        }

        /**
         * Shortcut to get the User executing this instance
         *
         * @return User
         * @since 1.18
         */
        public function getUser() {
                return $this->getContext()->getUser();
        }

        /**
         * Shortcut to get the skin being used for this instance
         *
         * @return Skin
         * @since 1.18
         */
        public function getSkin() {
                return $this->getContext()->getSkin();
        }

        /**
         * Shortcut to get user's language
         *
         * @deprecated since 1.19 Use getLanguage instead
         * @return Language
         * @since 1.18
         */
        public function getLang() {
                wfDeprecated( __METHOD__, '1.19' );
                return $this->getLanguage();
        }

        /**
         * Shortcut to get user's language
         *
         * @return Language
         * @since 1.19
         */
        public function getLanguage() {
                return $this->getContext()->getLanguage();
        }

        /**
         * Return the full title, including $par
         *
         * @return Title
         * @since 1.18
         */
        public function getFullTitle() {
                return $this->getContext()->getTitle();
        }

        /**
         * Wrapper around wfMessage that sets the current context.
         *
         * @return Message
         * @see wfMessage
         */
        public function msg( /* $args */ ) {
                // Note: can't use func_get_args() directly as second or later item in
                // a parameter list until PHP 5.3 or you get a fatal error.
                // Works fine as the first parameter, which appears elsewhere in the
                // code base. Sighhhh.
                $args = func_get_args();
                $message = call_user_func_array( array( $this->getContext(), 'msg' ), $args );
                // RequestContext passes context to wfMessage, and the language is set from
                // the context, but setting the language for Message class removes the
                // interface message status, which breaks for example usernameless gender
                // invocations. Restore the flag when not including special page in content.
                if ( $this->including() ) {
                        $message->setInterfaceMessageFlag( false );
                }
                return $message;
        }

        /**
         * Adds RSS/atom links
         *
         * @param $params array
         */
        protected function addFeedLinks( $params ) {
                global $wgFeedClasses;

                $feedTemplate = wfScript( 'api' );

                foreach ( $wgFeedClasses as $format => $class ) {
                        $theseParams = $params + array( 'feedformat' => $format );
                        $url = wfAppendQuery( $feedTemplate, $theseParams );
                        $this->getOutput()->addFeedLink( $format, $url );
                }
        }

        /**
         * Get the group that the special page belongs in on Special:SpecialPage
         * Use this method, instead of getGroupName to allow customization
         * of the group name from the wiki side
         *
         * @return string Group of this special page
         * @since 1.21
         */
        public function getFinalGroupName() {
                global $wgSpecialPageGroups;
                $name = $this->getName();
                $group = '-';

                // Allow overbidding the group from the wiki side
                $msg = $this->msg( 'specialpages-specialpagegroup-' . strtolower( $name ) )->inContentLanguage();
                if ( !$msg->isBlank() ) {
                        $group = $msg->text();
                } else {
                        // Than use the group from this object
                        $group = $this->getGroupName();

                        // Group '-' is used as default to have the chance to determine,
                        // if the special pages overrides this method,
                        // if not overridden, $wgSpecialPageGroups is checked for b/c
                        if ( $group === '-' && isset( $wgSpecialPageGroups[$name] ) ) {
                                $group = $wgSpecialPageGroups[$name];
                        }
                }

                // never give '-' back, change to 'other'
                if ( $group === '-' ) {
                        $group = 'other';
                }

                return $group;
        }

        /**
         * Under which header this special page is listed in Special:SpecialPages
         * See messages 'specialpages-group-*' for valid names
         * This method defaults to group 'other'
         *
         * @return string
         * @since 1.21
         */
        protected function getGroupName() {
                // '-' used here to determine, if this group is overridden or has a hardcoded 'other'
                // Needed for b/c in getFinalGroupName
                return '-';
        }
}

/**
 * Special page which uses an HTMLForm to handle processing.  This is mostly a
 * clone of FormAction.  More special pages should be built this way; maybe this could be
 * a new structure for SpecialPages
 */
abstract class FormSpecialPage extends SpecialPage {
        /**
         * The sub-page of the special page.
         * @var string
         */
        protected $par = null;

        /**
         * Get an HTMLForm descriptor array
         * @return Array
         */
        abstract protected function getFormFields();

        /**
         * Add pre-text to the form
         * @return String HTML which will be sent to $form->addPreText()
         */
        protected function preText() {
                return '';
        }

        /**
         * Add post-text to the form
         * @return String HTML which will be sent to $form->addPostText()
         */
        protected function postText() {
                return '';
        }

        /**
         * Play with the HTMLForm if you need to more substantially
         * @param $form HTMLForm
         */
        protected function alterForm( HTMLForm $form ) {
        }

        /**
         * Get message prefix for HTMLForm
         *
         * @since 1.21
         * @return string
         */
        protected function getMessagePrefix() {
                return strtolower( $this->getName() );
        }

        /**
         * Get the HTMLForm to control behavior
         * @return HTMLForm|null
         */
        protected function getForm() {
                $this->fields = $this->getFormFields();

                $form = new HTMLForm( $this->fields, $this->getContext(), $this->getMessagePrefix() );
                $form->setSubmitCallback( array( $this, 'onSubmit' ) );
                $form->setWrapperLegendMsg( $this->getMessagePrefix() . '-legend' );

                $headerMsg = $this->msg( $this->getMessagePrefix() . '-text' );
                if ( !$headerMsg->isDisabled() ) {
                        $form->addHeaderText( $headerMsg->parseAsBlock() );
                }

                // Retain query parameters (uselang etc)
                $params = array_diff_key(
                        $this->getRequest()->getQueryValues(), array( 'title' => null ) );
                $form->addHiddenField( 'redirectparams', wfArrayToCgi( $params ) );

                $form->addPreText( $this->preText() );
                $form->addPostText( $this->postText() );
                $this->alterForm( $form );

                // Give hooks a chance to alter the form, adding extra fields or text etc
                wfRunHooks( "Special{$this->getName()}BeforeFormDisplay", array( &$form ) );

                return $form;
        }

        /**
         * Process the form on POST submission.
         * @param  $data Array
         * @return Bool|Array true for success, false for didn't-try, array of errors on failure
         */
        abstract public function onSubmit( array $data );

        /**
         * Do something exciting on successful processing of the form, most likely to show a
         * confirmation message
         * @since 1.22 Default is to do nothing
         */
        public function onSuccess() {
        }

        /**
         * Basic SpecialPage workflow: get a form, send it to the user; get some data back,
         *
         * @param string $par Subpage string if one was specified
         */
        public function execute( $par ) {
                $this->setParameter( $par );
                $this->setHeaders();

                // This will throw exceptions if there's a problem
                $this->checkExecutePermissions( $this->getUser() );

                $form = $this->getForm();
                if ( $form->show() ) {
                        $this->onSuccess();
                }
        }

        /**
         * Maybe do something interesting with the subpage parameter
         * @param string $par
         */
        protected function setParameter( $par ) {
                $this->par = $par;
        }

        /**
         * Called from execute() to check if the given user can perform this action.
         * Failures here must throw subclasses of ErrorPageError.
         * @param $user User
         * @throws UserBlockedError
         * @return Bool true
         */
        protected function checkExecutePermissions( User $user ) {
                $this->checkPermissions();

                if ( $this->requiresUnblock() && $user->isBlocked() ) {
                        $block = $user->getBlock();
                        throw new UserBlockedError( $block );
                }

                if ( $this->requiresWrite() ) {
                        $this->checkReadOnly();
                }

                return true;
        }

        /**
         * Whether this action requires the wiki not to be locked
         * @return Bool
         */
        public function requiresWrite() {
                return true;
        }

        /**
         * Whether this action cannot be executed by a blocked user
         * @return Bool
         */
        public function requiresUnblock() {
                return true;
        }
}

/**
 * Shortcut to construct a special page which is unlisted by default
 * @ingroup SpecialPage
 */
class UnlistedSpecialPage extends SpecialPage {
        function __construct( $name, $restriction = '', $function = false, $file = 'default' ) {
                parent::__construct( $name, $restriction, false, $function, $file );
        }

        public function isListed() {
                return false;
        }
}

/**
 * Shortcut to construct an includable special  page
 * @ingroup SpecialPage
 */
class IncludableSpecialPage extends SpecialPage {
        function __construct(
                $name, $restriction = '', $listed = true, $function = false, $file = 'default'
        ) {
                parent::__construct( $name, $restriction, $listed, $function, $file, true );
        }

        public function isIncludable() {
                return true;
        }
}

/**
 * Shortcut to construct a special page alias.
 * @ingroup SpecialPage
 */
abstract class RedirectSpecialPage extends UnlistedSpecialPage {

        // Query parameters that can be passed through redirects
        protected $mAllowedRedirectParams = array();

        // Query parameters added by redirects
        protected $mAddedRedirectParams = array();

        public function execute( $par ) {
                $redirect = $this->getRedirect( $par );
                $query = $this->getRedirectQuery();
                // Redirect to a page title with possible query parameters
                if ( $redirect instanceof Title ) {
                        $url = $redirect->getFullURL( $query );
                        $this->getOutput()->redirect( $url );
                        return $redirect;
                } elseif ( $redirect === true ) {
                        // Redirect to index.php with query parameters
                        $url = wfAppendQuery( wfScript( 'index' ), $query );
                        $this->getOutput()->redirect( $url );
                        return $redirect;
                } else {
                        $class = get_class( $this );
                        throw new MWException( "RedirectSpecialPage $class doesn't redirect!" );
                }
        }

        /**
         * If the special page is a redirect, then get the Title object it redirects to.
         * False otherwise.
         *
         * @param string $par Subpage string
         * @return Title|bool
         */
        abstract public function getRedirect( $par );

        /**
         * Return part of the request string for a special redirect page
         * This allows passing, e.g. action=history to Special:Mypage, etc.
         *
         * @return String
         */
        public function getRedirectQuery() {
                $params = array();

                foreach ( $this->mAllowedRedirectParams as $arg ) {
                        if ( $this->getRequest()->getVal( $arg, null ) !== null ) {
                                $params[$arg] = $this->getRequest()->getVal( $arg );
                        }
                }

                foreach ( $this->mAddedRedirectParams as $arg => $val ) {
                        $params[$arg] = $val;
                }

                return count( $params )
                        ? $params
                        : false;
        }
}

abstract class SpecialRedirectToSpecial extends RedirectSpecialPage {
        // @todo FIXME: Visibility must be declared
        var $redirName, $redirSubpage;

        function __construct(
                $name, $redirName, $redirSubpage = false,
                $allowedRedirectParams = array(), $addedRedirectParams = array()
        ) {
                parent::__construct( $name );
                $this->redirName = $redirName;
                $this->redirSubpage = $redirSubpage;
                $this->mAllowedRedirectParams = $allowedRedirectParams;
                $this->mAddedRedirectParams = $addedRedirectParams;
        }

        public function getRedirect( $subpage ) {
                if ( $this->redirSubpage === false ) {
                        return SpecialPage::getTitleFor( $this->redirName, $subpage );
                } else {
                        return SpecialPage::getTitleFor( $this->redirName, $this->redirSubpage );
                }
        }
}

/**
 * ListAdmins --> ListUsers/sysop
 */
class SpecialListAdmins extends SpecialRedirectToSpecial {
        function __construct() {
                parent::__construct( 'Listadmins', 'Listusers', 'sysop' );
        }
}

/**
 * ListBots --> ListUsers/bot
 */
class SpecialListBots extends SpecialRedirectToSpecial {
        function __construct() {
                parent::__construct( 'Listbots', 'Listusers', 'bot' );
        }
}

/**
 * CreateAccount --> UserLogin/signup
 * @todo FIXME: This (and the rest of the login frontend) needs to die a horrible painful death
 */
class SpecialCreateAccount extends SpecialRedirectToSpecial {
        function __construct() {
                parent::__construct( 'CreateAccount', 'Userlogin', 'signup', array( 'uselang' ) );
        }
}
/**
 * SpecialMypage, SpecialMytalk and SpecialMycontributions special pages
 * are used to get user independent links pointing to the user page, talk
 * page and list of contributions.
 * This can let us cache a single copy of any generated content for all
 * users.
 */

/**
 * Superclass for any RedirectSpecialPage which redirects the user
 * to a particular article (as opposed to user contributions, logs, etc.).
 *
 * For security reasons these special pages are restricted to pass on
 * the following subset of GET parameters to the target page while
 * removing all others:
 *
 * - useskin, uselang, printable: to alter the appearance of the resulting page
 *
 * - redirect: allows viewing one's user page or talk page even if it is a
 * redirect.
 *
 * - rdfrom: allows redirecting to one's user page or talk page from an
 * external wiki with the "Redirect from..." notice.
 *
 * - limit, offset: Useful for linking to history of one's own user page or
 * user talk page. For example, this would be a link to "the last edit to your
 * user talk page in the year 2010":
 * http://en.wikipedia.org/wiki/Special:MyPage?offset=20110000000000&limit=1&action=history
 *
 * - feed: would allow linking to the current user's RSS feed for their user
 * talk page:
 * http://en.wikipedia.org/w/index.php?title=Special:MyTalk&action=history&feed=rss
 *
 * - preloadtitle: Can be used to provide a default section title for a
 * preloaded new comment on one's own talk page.
 *
 * - summary : Can be used to provide a default edit summary for a preloaded
 * edit to one's own user page or talk page.
 *
 * - preview: Allows showing/hiding preview on first edit regardless of user
 * preference, useful for preloaded edits where you know preview wouldn't be
 * useful.
 *
 * - internaledit, externaledit, mode: Allows forcing the use of the
 * internal/external editor, e.g. to force the internal editor for
 * short/simple preloaded edits.
 *
 * - redlink: Affects the message the user sees if their talk page/user talk
 * page does not currently exist. Avoids confusion for newbies with no user
 * pages over why they got a "permission error" following this link:
 * http://en.wikipedia.org/w/index.php?title=Special:MyPage&redlink=1
 *
 * - debug: determines whether the debug parameter is passed to load.php,
 * which disables reformatting and allows scripts to be debugged. Useful
 * when debugging scripts that manipulate one's own user page or talk page.
 *
 * @par Hook extension:
 * Extensions can add to the redirect parameters list by using the hook
 * RedirectSpecialArticleRedirectParams
 *
 * This hook allows extensions which add GET parameters like FlaggedRevs to
 * retain those parameters when redirecting using special pages.
 *
 * @par Hook extension example:
 * @code
 *      $wgHooks['RedirectSpecialArticleRedirectParams'][] =
 *              'MyExtensionHooks::onRedirectSpecialArticleRedirectParams';
 *      public static function onRedirectSpecialArticleRedirectParams( &$redirectParams ) {
 *              $redirectParams[] = 'stable';
 *              return true;
 *      }
 * @endcode
 * @ingroup SpecialPage
 */
abstract class RedirectSpecialArticle extends RedirectSpecialPage {
        function __construct( $name ) {
                parent::__construct( $name );
                $redirectParams = array(
                        'action',
                        'redirect', 'rdfrom',
                        # Options for preloaded edits
                        'preload', 'editintro', 'preloadtitle', 'summary', 'nosummary',
                        # Options for overriding user settings
                        'preview', 'internaledit', 'externaledit', 'mode', 'minor', 'watchthis',
                        # Options for history/diffs
                        'section', 'oldid', 'diff', 'dir',
                        'limit', 'offset', 'feed',
                        # Misc options
                        'redlink', 'debug',
                        # Options for action=raw; missing ctype can break JS or CSS in some browsers
                        'ctype', 'maxage', 'smaxage',
                );

                wfRunHooks( "RedirectSpecialArticleRedirectParams", array( &$redirectParams ) );
                $this->mAllowedRedirectParams = $redirectParams;
        }
}

/**
 * Shortcut to construct a special page pointing to current user user's page.
 * @ingroup SpecialPage
 */
class SpecialMypage extends RedirectSpecialArticle {
        function __construct() {
                parent::__construct( 'Mypage' );
        }

        function getRedirect( $subpage ) {
                if ( strval( $subpage ) !== '' ) {
                        return Title::makeTitle( NS_USER, $this->getUser()->getName() . '/' . $subpage );
                } else {
                        return Title::makeTitle( NS_USER, $this->getUser()->getName() );
                }
        }
}

/**
 * Shortcut to construct a special page pointing to current user talk page.
 * @ingroup SpecialPage
 */
class SpecialMytalk extends RedirectSpecialArticle {
        function __construct() {
                parent::__construct( 'Mytalk' );
        }

        function getRedirect( $subpage ) {
                if ( strval( $subpage ) !== '' ) {
                        return Title::makeTitle( NS_USER_TALK, $this->getUser()->getName() . '/' . $subpage );
                } else {
                        return Title::makeTitle( NS_USER_TALK, $this->getUser()->getName() );
                }
        }
}

/**
 * Shortcut to construct a special page pointing to current user contributions.
 * @ingroup SpecialPage
 */
class SpecialMycontributions extends RedirectSpecialPage {
        function __construct() {
                parent::__construct( 'Mycontributions' );
                $this->mAllowedRedirectParams = array( 'limit', 'namespace', 'tagfilter',
                        'offset', 'dir', 'year', 'month', 'feed' );
        }

        function getRedirect( $subpage ) {
                return SpecialPage::getTitleFor( 'Contributions', $this->getUser()->getName() );
        }
}

/**
 * Redirect to Special:Listfiles?user=$wgUser
 */
class SpecialMyuploads extends RedirectSpecialPage {
        function __construct() {
                parent::__construct( 'Myuploads' );
                $this->mAllowedRedirectParams = array( 'limit' );
        }

        function getRedirect( $subpage ) {
                return SpecialPage::getTitleFor( 'Listfiles', $this->getUser()->getName() );
        }
}

/**
 * Redirect from Special:PermanentLink/### to index.php?oldid=###
 */
class SpecialPermanentLink extends RedirectSpecialPage {
        function __construct() {
                parent::__construct( 'PermanentLink' );
                $this->mAllowedRedirectParams = array();
        }

        function getRedirect( $subpage ) {
                $subpage = intval( $subpage );
                if ( $subpage === 0 ) {
                        # throw an error page when no subpage was given
                        throw new ErrorPageError( 'nopagetitle', 'nopagetext' );
                }
                $this->mAddedRedirectParams['oldid'] = $subpage;
                return true;
        }
}