Follwup r75575, honour table prefixes. Bad Roan ;)

[mediawiki.git] / includes / OutputPage.php

<?php
if ( !defined( 'MEDIAWIKI' ) ) {
        die( 1 );
}

/**
 * @todo document
 */
class OutputPage {
        var $mMetatags = array(), $mKeywords = array(), $mLinktags = array();
        var $mExtStyles = array();
        var $mPagetitle = '', $mBodytext = '';

        /**
         * Holds the debug lines that will be outputted as comments in page source if
         * $wgDebugComments is enabled. See also $wgShowDebug.
         * TODO: make a getter method for this
         */
        public $mDebugtext = '';

        var $mHTMLtitle = '', $mIsarticle = true, $mPrintable = false;
        var $mSubtitle = '', $mRedirect = '', $mStatusCode;
        var $mLastModified = '', $mETag = false;
        var $mCategoryLinks = array(), $mCategories = array(), $mLanguageLinks = array();

        var $mScripts = '', $mInlineStyles = '', $mLinkColours, $mPageLinkTitle = '', $mHeadItems = array();
        var $mModules = array(), $mModuleScripts = array(), $mModuleStyles = array(), $mModuleMessages = array();
        var $mResourceLoader;
        var $mInlineMsg = array();

        var $mTemplateIds = array();

        var $mAllowUserJs;
        var $mSuppressQuickbar = false;
        var $mDoNothing = false;
        var $mContainsOldMagic = 0, $mContainsNewMagic = 0;
        var $mIsArticleRelated = true;
        protected $mParserOptions = null; // lazy initialised, use parserOptions()

        var $mFeedLinks = array();

        var $mEnableClientCache = true;
        var $mArticleBodyOnly = false;

        var $mNewSectionLink = false;
        var $mHideNewSectionLink = false;
        var $mNoGallery = false;
        var $mPageTitleActionText = '';
        var $mParseWarnings = array();
        var $mSquidMaxage = 0;
        var $mPreventClickjacking = true;
        var $mRevisionId = null;
        protected $mTitle = null;

        /**
         * An array of stylesheet filenames (relative from skins path), with options
         * for CSS media, IE conditions, and RTL/LTR direction.
         * For internal use; add settings in the skin via $this->addStyle()
         */
        var $styles = array();

        /**
         * Whether to load jQuery core.
         */
        protected $mJQueryDone = false;

        private $mIndexPolicy = 'index';
        private $mFollowPolicy = 'follow';
        private $mVaryHeader = array(
                'Accept-Encoding' => array( 'list-contains=gzip' ),
                'Cookie' => null
        );

        /**
         * Constructor
         * Initialise private variables
         */
        function __construct() {
                global $wgAllowUserJs;
                $this->mAllowUserJs = $wgAllowUserJs;
        }

        /**
         * Redirect to $url rather than displaying the normal page
         *
         * @param $url String: URL
         * @param $responsecode String: HTTP status code
         */
        public function redirect( $url, $responsecode = '302' ) {
                # Strip newlines as a paranoia check for header injection in PHP<5.1.2
                $this->mRedirect = str_replace( "\n", '', $url );
                $this->mRedirectCode = $responsecode;
        }

        /**
         * Get the URL to redirect to, or an empty string if not redirect URL set
         *
         * @return String
         */
        public function getRedirect() {
                return $this->mRedirect;
        }

        /**
         * Set the HTTP status code to send with the output.
         *
         * @param $statusCode Integer
         * @return nothing
         */
        public function setStatusCode( $statusCode ) {
                $this->mStatusCode = $statusCode;
        }

        /**
         * Add a new <meta> tag
         * To add an http-equiv meta tag, precede the name with "http:"
         *
         * @param $name tag name
         * @param $val tag value
         */
        function addMeta( $name, $val ) {
                array_push( $this->mMetatags, array( $name, $val ) );
        }

        /**
         * Add a keyword or a list of keywords in the page header
         *
         * @param $text String or array of strings
         */
        function addKeyword( $text ) {
                if( is_array( $text ) ) {
                        $this->mKeywords = array_merge( $this->mKeywords, $text );
                } else {
                        array_push( $this->mKeywords, $text );
                }
        }

        /**
         * Add a new \<link\> tag to the page header
         *
         * @param $linkarr Array: associative array of attributes.
         */
        function addLink( $linkarr ) {
                array_push( $this->mLinktags, $linkarr );
        }

        /**
         * Add a new \<link\> with "rel" attribute set to "meta"
         *
         * @param $linkarr Array: associative array mapping attribute names to their
         *                 values, both keys and values will be escaped, and the
         *                 "rel" attribute will be automatically added
         */
        function addMetadataLink( $linkarr ) {
                # note: buggy CC software only reads first "meta" link
                static $haveMeta = false;
                $linkarr['rel'] = $haveMeta ? 'alternate meta' : 'meta';
                $this->addLink( $linkarr );
                $haveMeta = true;
        }

        /**
         * Add raw HTML to the list of scripts (including \<script\> tag, etc.)
         *
         * @param $script String: raw HTML
         */
        function addScript( $script ) {
                $this->mScripts .= $script . "\n";
        }

        /**
         * Register and add a stylesheet from an extension directory.
         *
         * @param $url String path to sheet.  Provide either a full url (beginning
         *             with 'http', etc) or a relative path from the document root
         *             (beginning with '/').  Otherwise it behaves identically to
         *             addStyle() and draws from the /skins folder.
         */
        public function addExtensionStyle( $url ) {
                array_push( $this->mExtStyles, $url );
        }

        /**
         * Get all links added by extensions
         *
         * @return Array
         */
        function getExtStyle() {
                return $this->mExtStyles;
        }

        /**
         * Add a JavaScript file out of skins/common, or a given relative path.
         *
         * @param $file String: filename in skins/common or complete on-server path
         *              (/foo/bar.js)
         * @param $version String: style version of the file. Defaults to $wgStyleVersion
         */
        public function addScriptFile( $file, $version = null ) {
                global $wgStylePath, $wgStyleVersion;
                // See if $file parameter is an absolute URL or begins with a slash
                if( substr( $file, 0, 1 ) == '/' || preg_match( '#^[a-z]*://#i', $file ) ) {
                        $path = $file;
                } else {
                        $path = "{$wgStylePath}/common/{$file}";
                }
                if ( is_null( $version ) )
                        $version = $wgStyleVersion;
                $this->addScript( Html::linkedScript( wfAppendQuery( $path, $version ) ) );
        }

        /**
         * Add a self-contained script tag with the given contents
         *
         * @param $script String: JavaScript text, no <script> tags
         */
        public function addInlineScript( $script ) {
                $this->mScripts .= Html::inlineScript( "\n$script\n" ) . "\n";
        }

        /**
         * Get all registered JS and CSS tags for the header.
         *
         * @return String
         */
        function getScript() {
                return $this->mScripts . $this->getHeadItems();
        }

        /**
         * Get the list of modules to include on this page
         *
         * @return Array of module names
         */
        public function getModules() {
                return array_values( array_unique( $this->mModules ) );
        }

        /**
         * Add one or more modules recognized by the resource loader. Modules added
         * through this function will be loaded by the resource loader when the
         * page loads.
         *
         * @param $modules Mixed: module name (string) or array of module names
         */
        public function addModules( $modules ) {
                $this->mModules = array_merge( $this->mModules, (array)$modules );
        }

        /**
         * Get the list of module JS to include on this page
         * @return array of module names
         */
        public function getModuleScripts() {
                return array_values( array_unique( $this->mModuleScripts ) );
        }

        /**
         * Add only JS of one or more modules recognized by the resource loader. Module
         * scripts added through this function will be loaded by the resource loader when
         * the page loads.
         *
         * @param $modules Mixed: module name (string) or array of module names
         */
        public function addModuleScripts( $modules ) {
                $this->mModuleScripts = array_merge( $this->mModuleScripts, (array)$modules );
        }

        /**
         * Get the list of module CSS to include on this page
         *
         * @return Array of module names
         */
        public function getModuleStyles() {
                return array_values( array_unique( $this->mModuleStyles ) );
        }

        /**
         * Add only CSS of one or more modules recognized by the resource loader. Module
         * styles added through this function will be loaded by the resource loader when
         * the page loads.
         *
         * @param $modules Mixed: module name (string) or array of module names
         */
        public function addModuleStyles( $modules ) {
                $this->mModuleStyles = array_merge( $this->mModuleStyles, (array)$modules );
        }

        /**
         * Get the list of module messages to include on this page
         *
         * @return Array of module names
         */
        public function getModuleMessages() {
                return array_values( array_unique( $this->mModuleMessages ) );
        }

        /**
         * Add only messages of one or more modules recognized by the resource loader.
         * Module messages added through this function will be loaded by the resource
         * loader when the page loads.
         *
         * @param $modules Mixed: module name (string) or array of module names
         */
        public function addModuleMessages( $modules ) {
                $this->mModuleMessages = array_merge( $this->mModuleMessages, (array)$modules );
        }

        /**
         * Get all header items in a string
         *
         * @return String
         */
        function getHeadItems() {
                $s = '';
                foreach ( $this->mHeadItems as $item ) {
                        $s .= $item;
                }
                return $s;
        }

        /**
         * Add or replace an header item to the output
         *
         * @param $name String: item name
         * @param $value String: raw HTML
         */
        public function addHeadItem( $name, $value ) {
                $this->mHeadItems[$name] = $value;
        }

        /**
         * Check if the header item $name is already set
         *
         * @param $name String: item name
         * @return Boolean
         */
        public function hasHeadItem( $name ) {
                return isset( $this->mHeadItems[$name] );
        }

        /**
         * Set the value of the ETag HTTP header, only used if $wgUseETag is true
         *
         * @param $tag String: value of "ETag" header
         */
        function setETag( $tag ) {
                $this->mETag = $tag;
        }

        /**
         * Set whether the output should only contain the body of the article,
         * without any skin, sidebar, etc.
         * Used e.g. when calling with "action=render".
         *
         * @param $only Boolean: whether to output only the body of the article
         */
        public function setArticleBodyOnly( $only ) {
                $this->mArticleBodyOnly = $only;
        }

        /**
         * Return whether the output will contain only the body of the article
         *
         * @return Boolean
         */
        public function getArticleBodyOnly() {
                return $this->mArticleBodyOnly;
        }

        /**
         * checkLastModified tells the client to use the client-cached page if
         * possible. If sucessful, the OutputPage is disabled so that
         * any future call to OutputPage->output() have no effect.
         *
         * Side effect: sets mLastModified for Last-Modified header
         *
         * @return Boolean: true iff cache-ok headers was sent.
         */
        public function checkLastModified( $timestamp ) {
                global $wgCachePages, $wgCacheEpoch, $wgUser, $wgRequest;

                if ( !$timestamp || $timestamp == '19700101000000' ) {
                        wfDebug( __METHOD__ . ": CACHE DISABLED, NO TIMESTAMP\n" );
                        return false;
                }
                if( !$wgCachePages ) {
                        wfDebug( __METHOD__ . ": CACHE DISABLED\n", false );
                        return false;
                }
                if( $wgUser->getOption( 'nocache' ) ) {
                        wfDebug( __METHOD__ . ": USER DISABLED CACHE\n", false );
                        return false;
                }

                $timestamp = wfTimestamp( TS_MW, $timestamp );
                $modifiedTimes = array(
                        'page' => $timestamp,
                        'user' => $wgUser->getTouched(),
                        'epoch' => $wgCacheEpoch
                );
                wfRunHooks( 'OutputPageCheckLastModified', array( &$modifiedTimes ) );

                $maxModified = max( $modifiedTimes );
                $this->mLastModified = wfTimestamp( TS_RFC2822, $maxModified );

                if( empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
                        wfDebug( __METHOD__ . ": client did not send If-Modified-Since header\n", false );
                        return false;
                }

                # Make debug info
                $info = '';
                foreach ( $modifiedTimes as $name => $value ) {
                        if ( $info !== '' ) {
                                $info .= ', ';
                        }
                        $info .= "$name=" . wfTimestamp( TS_ISO_8601, $value );
                }

                # IE sends sizes after the date like this:
                # Wed, 20 Aug 2003 06:51:19 GMT; length=5202
                # this breaks strtotime().
                $clientHeader = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );

                wfSuppressWarnings(); // E_STRICT system time bitching
                $clientHeaderTime = strtotime( $clientHeader );
                wfRestoreWarnings();
                if ( !$clientHeaderTime ) {
                        wfDebug( __METHOD__ . ": unable to parse the client's If-Modified-Since header: $clientHeader\n" );
                        return false;
                }
                $clientHeaderTime = wfTimestamp( TS_MW, $clientHeaderTime );

                wfDebug( __METHOD__ . ": client sent If-Modified-Since: " .
                        wfTimestamp( TS_ISO_8601, $clientHeaderTime ) . "\n", false );
                wfDebug( __METHOD__ . ": effective Last-Modified: " .
                        wfTimestamp( TS_ISO_8601, $maxModified ) . "\n", false );
                if( $clientHeaderTime < $maxModified ) {
                        wfDebug( __METHOD__ . ": STALE, $info\n", false );
                        return false;
                }

                # Not modified
                # Give a 304 response code and disable body output
                wfDebug( __METHOD__ . ": NOT MODIFIED, $info\n", false );
                ini_set( 'zlib.output_compression', 0 );
                $wgRequest->response()->header( "HTTP/1.1 304 Not Modified" );
                $this->sendCacheControl();
                $this->disable();

                // Don't output a compressed blob when using ob_gzhandler;
                // it's technically against HTTP spec and seems to confuse
                // Firefox when the response gets split over two packets.
                wfClearOutputBuffers();

                return true;
        }

        /**
         * Override the last modified timestamp
         *
         * @param $timestamp String: new timestamp, in a format readable by
         *        wfTimestamp()
         */
        public function setLastModified( $timestamp ) {
                $this->mLastModified = wfTimestamp( TS_RFC2822, $timestamp );
        }

        /**
         * Set the robot policy for the page: <http://www.robotstxt.org/meta.html>
         *
         * @param $policy String: the literal string to output as the contents of
         *   the meta tag.  Will be parsed according to the spec and output in
         *   standardized form.
         * @return null
         */
        public function setRobotPolicy( $policy ) {
                $policy = Article::formatRobotPolicy( $policy );

                if( isset( $policy['index'] ) ) {
                        $this->setIndexPolicy( $policy['index'] );
                }
                if( isset( $policy['follow'] ) ) {
                        $this->setFollowPolicy( $policy['follow'] );
                }
        }

        /**
         * Set the index policy for the page, but leave the follow policy un-
         * touched.
         *
         * @param $policy string Either 'index' or 'noindex'.
         * @return null
         */
        public function setIndexPolicy( $policy ) {
                $policy = trim( $policy );
                if( in_array( $policy, array( 'index', 'noindex' ) ) ) {
                        $this->mIndexPolicy = $policy;
                }
        }

        /**
         * Set the follow policy for the page, but leave the index policy un-
         * touched.
         *
         * @param $policy String: either 'follow' or 'nofollow'.
         * @return null
         */
        public function setFollowPolicy( $policy ) {
                $policy = trim( $policy );
                if( in_array( $policy, array( 'follow', 'nofollow' ) ) ) {
                        $this->mFollowPolicy = $policy;
                }
        }

        /**
         * Set the new value of the "action text", this will be added to the
         * "HTML title", separated from it with " - ".
         *
         * @param $text String: new value of the "action text"
         */
        public function setPageTitleActionText( $text ) {
                $this->mPageTitleActionText = $text;
        }

        /**
         * Get the value of the "action text"
         *
         * @return String
         */
        public function getPageTitleActionText() {
                if ( isset( $this->mPageTitleActionText ) ) {
                        return $this->mPageTitleActionText;
                }
        }

        /**
         * "HTML title" means the contents of <title>.
         * It is stored as plain, unescaped text and will be run through htmlspecialchars in the skin file.
         */
        public function setHTMLTitle( $name ) {
                $this->mHTMLtitle = $name;
        }

        /**
         * Return the "HTML title", i.e. the content of the <title> tag.
         *
         * @return String
         */
        public function getHTMLTitle() {
                return $this->mHTMLtitle;
        }

        /**
         * "Page title" means the contents of \<h1\>. It is stored as a valid HTML fragment.
         * This function allows good tags like \<sup\> in the \<h1\> tag, but not bad tags like \<script\>.
         * This function automatically sets \<title\> to the same content as \<h1\> but with all tags removed.
         * Bad tags that were escaped in \<h1\> will still be escaped in \<title\>, and good tags like \<i\> will be dropped entirely.
         */
        public function setPageTitle( $name ) {
                # change "<script>foo&bar</script>" to "&lt;script&gt;foo&amp;bar&lt;/script&gt;"
                # but leave "<i>foobar</i>" alone
                $nameWithTags = Sanitizer::normalizeCharReferences( Sanitizer::removeHTMLtags( $name ) );
                $this->mPagetitle = $nameWithTags;

                # change "<i>foo&amp;bar</i>" to "foo&bar"
                $this->setHTMLTitle( wfMsg( 'pagetitle', Sanitizer::stripAllTags( $nameWithTags ) ) );
        }

        /**
         * Return the "page title", i.e. the content of the \<h1\> tag.
         *
         * @return String
         */
        public function getPageTitle() {
                return $this->mPagetitle;
        }

        /**
         * Set the Title object to use
         *
         * @param $t Title object
         */
        public function setTitle( $t ) {
                $this->mTitle = $t;
        }

        /**
         * Get the Title object used in this instance
         *
         * @return Title
         */
        public function getTitle() {
                if ( $this->mTitle instanceof Title ) {
                        return $this->mTitle;
                } else {
                        wfDebug( __METHOD__ . " called and \$mTitle is null. Return \$wgTitle for sanity\n" );
                        global $wgTitle;
                        return $wgTitle;
                }
        }

        /**
         * Replace the subtile with $str
         *
         * @param $str String: new value of the subtitle
         */
        public function setSubtitle( $str ) {
                $this->mSubtitle = /*$this->parse(*/ $str /*)*/; // @bug 2514
        }

        /**
         * Add $str to the subtitle
         *
         * @param $str String to add to the subtitle
         */
        public function appendSubtitle( $str ) {
                $this->mSubtitle .= /*$this->parse(*/ $str /*)*/; // @bug 2514
        }

        /**
         * Get the subtitle
         *
         * @return String
         */
        public function getSubtitle() {
                return $this->mSubtitle;
        }

        /**
         * Set the page as printable, i.e. it'll be displayed with with all
         * print styles included
         */
        public function setPrintable() {
                $this->mPrintable = true;
        }

        /**
         * Return whether the page is "printable"
         *
         * @return Boolean
         */
        public function isPrintable() {
                return $this->mPrintable;
        }

        /**
         * Disable output completely, i.e. calling output() will have no effect
         */
        public function disable() {
                $this->mDoNothing = true;
        }

        /**
         * Return whether the output will be completely disabled
         *
         * @return Boolean
         */
        public function isDisabled() {
                return $this->mDoNothing;
        }

        /**
         * Show an "add new section" link?
         *
         * @return Boolean
         */
        public function showNewSectionLink() {
                return $this->mNewSectionLink;
        }

        /**
         * Forcibly hide the new section link?
         *
         * @return Boolean
         */
        public function forceHideNewSectionLink() {
                return $this->mHideNewSectionLink;
        }

        /**
         * Add or remove feed links in the page header
         * This is mainly kept for backward compatibility, see OutputPage::addFeedLink()
         * for the new version
         * @see addFeedLink()
         *
         * @param $show Boolean: true: add default feeds, false: remove all feeds
         */
        public function setSyndicated( $show = true ) {
                if ( $show ) {
                        $this->setFeedAppendQuery( false );
                } else {
                        $this->mFeedLinks = array();
                }
        }

        /**
         * Add default feeds to the page header
         * This is mainly kept for backward compatibility, see OutputPage::addFeedLink()
         * for the new version
         * @see addFeedLink()
         *
         * @param $val String: query to append to feed links or false to output
         *        default links
         */
        public function setFeedAppendQuery( $val ) {
                global $wgAdvertisedFeedTypes;

                $this->mFeedLinks = array();

                foreach ( $wgAdvertisedFeedTypes as $type ) {
                        $query = "feed=$type";
                        if ( is_string( $val ) ) {
                                $query .= '&' . $val;
                        }
                        $this->mFeedLinks[$type] = $this->getTitle()->getLocalURL( $query );
                }
        }

        /**
         * Add a feed link to the page header
         *
         * @param $format String: feed type, should be a key of $wgFeedClasses
         * @param $href String: URL
         */
        public function addFeedLink( $format, $href ) {
                global $wgAdvertisedFeedTypes;

                if ( in_array( $format, $wgAdvertisedFeedTypes ) ) {
                        $this->mFeedLinks[$format] = $href;
                }
        }

        /**
         * Should we output feed links for this page?
         * @return Boolean
         */
        public function isSyndicated() {
                return count( $this->mFeedLinks ) > 0;
        }

        /**
         * Return URLs for each supported syndication format for this page.
         * @return array associating format keys with URLs
         */
        public function getSyndicationLinks() {
                return $this->mFeedLinks;
        }

        /**
         * Will currently always return null
         *
         * @return null
         */
        public function getFeedAppendQuery() {
                return $this->mFeedLinksAppendQuery;
        }

        /**
         * Set whether the displayed content is related to the source of the
         * corresponding article on the wiki
         * Setting true will cause the change "article related" toggle to true
         *
         * @param $v Boolean
         */
        public function setArticleFlag( $v ) {
                $this->mIsarticle = $v;
                if ( $v ) {
                        $this->mIsArticleRelated = $v;
                }
        }

        /**
         * Return whether the content displayed page is related to the source of
         * the corresponding article on the wiki
         *
         * @return Boolean
         */
        public function isArticle() {
                return $this->mIsarticle;
        }

        /**
         * Set whether this page is related an article on the wiki
         * Setting false will cause the change of "article flag" toggle to false
         *
         * @param $v Boolean
         */
        public function setArticleRelated( $v ) {
                $this->mIsArticleRelated = $v;
                if ( !$v ) {
                        $this->mIsarticle = false;
                }
        }

        /**
         * Return whether this page is related an article on the wiki
         *
         * @return Boolean
         */
        public function isArticleRelated() {
                return $this->mIsArticleRelated;
        }

        /**
         * Add new language links
         *
         * @param $newLinkArray Associative array mapping language code to the page
         *                      name
         */
        public function addLanguageLinks( $newLinkArray ) {
                $this->mLanguageLinks += $newLinkArray;
        }

        /**
         * Reset the language links and add new language links
         *
         * @param $newLinkArray Associative array mapping language code to the page
         *                      name
         */
        public function setLanguageLinks( $newLinkArray ) {
                $this->mLanguageLinks = $newLinkArray;
        }

        /**
         * Get the list of language links
         *
         * @return Associative array mapping language code to the page name
         */
        public function getLanguageLinks() {
                return $this->mLanguageLinks;
        }

        /**
         * Add an array of categories, with names in the keys
         *
         * @param $categories Associative array mapping category name to its sort key
         */
        public function addCategoryLinks( $categories ) {
                global $wgUser, $wgContLang;

                if ( !is_array( $categories ) || count( $categories ) == 0 ) {
                        return;
                }

                # Add the links to a LinkBatch
                $arr = array( NS_CATEGORY => $categories );
                $lb = new LinkBatch;
                $lb->setArray( $arr );

                # Fetch existence plus the hiddencat property
                $dbr = wfGetDB( DB_SLAVE );
                $pageTable = $dbr->tableName( 'page' );
                $where = $lb->constructSet( 'page', $dbr );
                $propsTable = $dbr->tableName( 'page_props' );
                $sql = "SELECT page_id, page_namespace, page_title, page_len, page_is_redirect, page_latest, pp_value
                        FROM $pageTable LEFT JOIN $propsTable ON pp_propname='hiddencat' AND pp_page=page_id WHERE $where";
                $res = $dbr->query( $sql, __METHOD__ );

                # Add the results to the link cache
                $lb->addResultToCache( LinkCache::singleton(), $res );

                # Set all the values to 'normal'. This can be done with array_fill_keys in PHP 5.2.0+
                $categories = array_combine(
                        array_keys( $categories ),
                        array_fill( 0, count( $categories ), 'normal' )
                );

                # Mark hidden categories
                foreach ( $res as $row ) {
                        if ( isset( $row->pp_value ) ) {
                                $categories[$row->page_title] = 'hidden';
                        }
                }

                # Add the remaining categories to the skin
                if ( wfRunHooks( 'OutputPageMakeCategoryLinks', array( &$this, $categories, &$this->mCategoryLinks ) ) ) {
                        $sk = $wgUser->getSkin();
                        foreach ( $categories as $category => $type ) {
                                $origcategory = $category;
                                $title = Title::makeTitleSafe( NS_CATEGORY, $category );
                                $wgContLang->findVariantLink( $category, $title, true );
                                if ( $category != $origcategory ) {
                                        if ( array_key_exists( $category, $categories ) ) {
                                                continue;
                                        }
                                }
                                $text = $wgContLang->convertHtml( $title->getText() );
                                $this->mCategories[] = $title->getText();
                                $this->mCategoryLinks[$type][] = $sk->link( $title, $text );
                        }
                }
        }

        /**
         * Reset the category links (but not the category list) and add $categories
         *
         * @param $categories Associative array mapping category name to its sort key
         */
        public function setCategoryLinks( $categories ) {
                $this->mCategoryLinks = array();
                $this->addCategoryLinks( $categories );
        }

        /**
         * Get the list of category links, in a 2-D array with the following format:
         * $arr[$type][] = $link, where $type is either "normal" or "hidden" (for
         * hidden categories) and $link a HTML fragment with a link to the category
         * page
         *
         * @return Array
         */
        public function getCategoryLinks() {
                return $this->mCategoryLinks;
        }

        /**
         * Get the list of category names this page belongs to
         *
         * @return Array of strings
         */
        public function getCategories() {
                return $this->mCategories;
        }

        /**
         * Suppress the quickbar from the output, only for skin supporting
         * the quickbar
         */
        public function suppressQuickbar() {
                $this->mSuppressQuickbar = true;
        }

        /**
         * Return whether the quickbar should be suppressed from the output
         *
         * @return Boolean
         */
        public function isQuickbarSuppressed() {
                return $this->mSuppressQuickbar;
        }

        /**
         * Remove user JavaScript from scripts to load
         */
        public function disallowUserJs() {
                $this->mAllowUserJs = false;
        }

        /**
         * Return whether user JavaScript is allowed for this page
         *
         * @return Boolean
         */
        public function isUserJsAllowed() {
                return $this->mAllowUserJs;
        }

        /**
         * Prepend $text to the body HTML
         *
         * @param $text String: HTML
         */
        public function prependHTML( $text ) {
                $this->mBodytext = $text . $this->mBodytext;
        }

        /**
         * Append $text to the body HTML
         *
         * @param $text String: HTML
         */
        public function addHTML( $text ) {
                $this->mBodytext .= $text;
        }

        /**
         * Clear the body HTML
         */
        public function clearHTML() {
                $this->mBodytext = '';
        }

        /**
         * Get the body HTML
         *
         * @return String: HTML
         */
        public function getHTML() {
                return $this->mBodytext;
        }

        /**
         * Add $text to the debug output
         *
         * @param $text String: debug text
         */
        public function debug( $text ) {
                $this->mDebugtext .= $text;
        }

        /**
         * Get/set the ParserOptions object to use for wikitext parsing
         *
         * @param $options either the ParserOption to use or null to only get the
         *                 current ParserOption object
         * @return current ParserOption object
         */
        public function parserOptions( $options = null ) {
                if ( !$this->mParserOptions ) {
                        $this->mParserOptions = new ParserOptions;
                }
                return wfSetVar( $this->mParserOptions, $options );
        }

        /**
         * Set the revision ID which will be seen by the wiki text parser
         * for things such as embedded {{REVISIONID}} variable use.
         *
         * @param $revid Mixed: an positive integer, or null
         * @return Mixed: previous value
         */
        public function setRevisionId( $revid ) {
                $val = is_null( $revid ) ? null : intval( $revid );
                return wfSetVar( $this->mRevisionId, $val );
        }

        /**
         * Get the current revision ID
         *
         * @return Integer
         */
        public function getRevisionId() {
                return $this->mRevisionId;
        }

        /**
         * Convert wikitext to HTML and add it to the buffer
         * Default assumes that the current page title will be used.
         *
         * @param $text String
         * @param $linestart Boolean: is this the start of a line?
         */
        public function addWikiText( $text, $linestart = true ) {
                $title = $this->getTitle(); // Work arround E_STRICT
                $this->addWikiTextTitle( $text, $title, $linestart );
        }

        /**
         * Add wikitext with a custom Title object
         *
         * @param $text String: wikitext
         * @param $title Title object
         * @param $linestart Boolean: is this the start of a line?
         */
        public function addWikiTextWithTitle( $text, &$title, $linestart = true ) {
                $this->addWikiTextTitle( $text, $title, $linestart );
        }

        /**
         * Add wikitext with a custom Title object and
         *
         * @param $text String: wikitext
         * @param $title Title object
         * @param $linestart Boolean: is this the start of a line?
         */
        function addWikiTextTitleTidy( $text, &$title, $linestart = true ) {
                $this->addWikiTextTitle( $text, $title, $linestart, true );
        }

        /**
         * Add wikitext with tidy enabled
         *
         * @param $text String: wikitext
         * @param $linestart Boolean: is this the start of a line?
         */
        public function addWikiTextTidy( $text, $linestart = true ) {
                $title = $this->getTitle();
                $this->addWikiTextTitleTidy( $text, $title, $linestart );
        }

        /**
         * Add wikitext with a custom Title object
         *
         * @param $text String: wikitext
         * @param $title Title object
         * @param $linestart Boolean: is this the start of a line?
         * @param $tidy Boolean: whether to use tidy
         */
        public function addWikiTextTitle( $text, &$title, $linestart, $tidy = false ) {
                global $wgParser;

                wfProfileIn( __METHOD__ );

                wfIncrStats( 'pcache_not_possible' );

                $popts = $this->parserOptions();
                $oldTidy = $popts->setTidy( $tidy );

                $parserOutput = $wgParser->parse(
                        $text, $title, $popts,
                        $linestart, true, $this->mRevisionId
                );

                $popts->setTidy( $oldTidy );

                $this->addParserOutput( $parserOutput );

                wfProfileOut( __METHOD__ );
        }

        /**
         * Add a ParserOutput object, but without Html
         *
         * @param $parserOutput ParserOutput object
         */
        public function addParserOutputNoText( &$parserOutput ) {
                $this->mLanguageLinks += $parserOutput->getLanguageLinks();
                $this->addCategoryLinks( $parserOutput->getCategories() );
                $this->mNewSectionLink = $parserOutput->getNewSection();
                $this->mHideNewSectionLink = $parserOutput->getHideNewSection();

                $this->mParseWarnings = $parserOutput->getWarnings();
                if ( !$parserOutput->isCacheable() ) {
                        $this->enableClientCache( false );
                }
                $this->mNoGallery = $parserOutput->getNoGallery();
                $this->mHeadItems = array_merge( $this->mHeadItems, $parserOutput->getHeadItems() );
                $this->addModules( $parserOutput->getModules() );
                // Versioning...
                foreach ( (array)$parserOutput->mTemplateIds as $ns => $dbks ) {
                        if ( isset( $this->mTemplateIds[$ns] ) ) {
                                $this->mTemplateIds[$ns] = $dbks + $this->mTemplateIds[$ns];
                        } else {
                                $this->mTemplateIds[$ns] = $dbks;
                        }
                }

                // Hooks registered in the object
                global $wgParserOutputHooks;
                foreach ( $parserOutput->getOutputHooks() as $hookInfo ) {
                        list( $hookName, $data ) = $hookInfo;
                        if ( isset( $wgParserOutputHooks[$hookName] ) ) {
                                call_user_func( $wgParserOutputHooks[$hookName], $this, $parserOutput, $data );
                        }
                }

                wfRunHooks( 'OutputPageParserOutput', array( &$this, $parserOutput ) );
        }

        /**
         * Add a ParserOutput object
         *
         * @param $parserOutput ParserOutput
         */
        function addParserOutput( &$parserOutput ) {
                $this->addParserOutputNoText( $parserOutput );
                $text = $parserOutput->getText();
                wfRunHooks( 'OutputPageBeforeHTML', array( &$this, &$text ) );
                $this->addHTML( $text );
        }


        /**
         * Add the output of a QuickTemplate to the output buffer
         *
         * @param $template QuickTemplate
         */
        public function addTemplate( &$template ) {
                ob_start();
                $template->execute();
                $this->addHTML( ob_get_contents() );
                ob_end_clean();
        }

        /**
         * Parse wikitext and return the HTML.
         *
         * @param $text String
         * @param $linestart Boolean: is this the start of a line?
         * @param $interface Boolean: use interface language ($wgLang instead of
         *                   $wgContLang) while parsing language sensitive magic
         *                   words like GRAMMAR and PLURAL
         * @param $language  Language object: target language object, will override
         *                   $interface
         * @return String: HTML
         */
        public function parse( $text, $linestart = true, $interface = false, $language = null ) {
                // Check one for one common cause for parser state resetting
                $callers = wfGetAllCallers( 10 );
                if ( strpos( $callers, 'Parser::extensionSubstitution' ) !== false ) {
                        throw new MWException( "wfMsg* function with parsing cannot be used " .
                                "inside a tag hook. Should use parser->recursiveTagParse() instead" );
                }

                global $wgParser;

                if( is_null( $this->getTitle() ) ) {
                        throw new MWException( 'Empty $mTitle in ' . __METHOD__ );
                }

                $popts = $this->parserOptions();
                if ( $interface ) {
                        $popts->setInterfaceMessage( true );
                }
                if ( $language !== null ) {
                        $oldLang = $popts->setTargetLanguage( $language );
                }

                $parserOutput = $wgParser->parse(
                        $text, $this->getTitle(), $popts,
                        $linestart, true, $this->mRevisionId
                );

                if ( $interface ) {
                        $popts->setInterfaceMessage( false );
                }
                if ( $language !== null ) {
                        $popts->setTargetLanguage( $oldLang );
                }

                return $parserOutput->getText();
        }

        /**
         * Parse wikitext, strip paragraphs, and return the HTML.
         *
         * @param $text String
         * @param $linestart Boolean: is this the start of a line?
         * @param $interface Boolean: use interface language ($wgLang instead of
         *                   $wgContLang) while parsing language sensitive magic
         *                   words like GRAMMAR and PLURAL
         * @return String: HTML
         */
        public function parseInline( $text, $linestart = true, $interface = false ) {
                $parsed = $this->parse( $text, $linestart, $interface );

                $m = array();
                if ( preg_match( '/^<p>(.*)\n?<\/p>\n?/sU', $parsed, $m ) ) {
                        $parsed = $m[1];
                }

                return $parsed;
        }

        /**
         * Set the value of the "s-maxage" part of the "Cache-control" HTTP header
         *
         * @param $maxage Integer: maximum cache time on the Squid, in seconds.
         */
        public function setSquidMaxage( $maxage ) {
                $this->mSquidMaxage = $maxage;
        }

        /**
         * Use enableClientCache(false) to force it to send nocache headers
         *
         * @param $state ??
         */
        public function enableClientCache( $state ) {
                return wfSetVar( $this->mEnableClientCache, $state );
        }

        /**
         * Get the list of cookies that will influence on the cache
         *
         * @return Array
         */
        function getCacheVaryCookies() {
                global $wgCookiePrefix, $wgCacheVaryCookies;
                static $cookies;
                if ( $cookies === null ) {
                        $cookies = array_merge(
                                array(
                                        "{$wgCookiePrefix}Token",
                                        "{$wgCookiePrefix}LoggedOut",
                                        session_name()
                                ),
                                $wgCacheVaryCookies
                        );
                        wfRunHooks( 'GetCacheVaryCookies', array( $this, &$cookies ) );
                }
                return $cookies;
        }

        /**
         * Return whether this page is not cacheable because "useskin" or "uselang"
         * URL parameters were passed.
         *
         * @return Boolean
         */
        function uncacheableBecauseRequestVars() {
                global $wgRequest;
                return $wgRequest->getText( 'useskin', false ) === false
                        && $wgRequest->getText( 'uselang', false ) === false;
        }

        /**
         * Check if the request has a cache-varying cookie header
         * If it does, it's very important that we don't allow public caching
         *
         * @return Boolean
         */
        function haveCacheVaryCookies() {
                global $wgRequest;
                $cookieHeader = $wgRequest->getHeader( 'cookie' );
                if ( $cookieHeader === false ) {
                        return false;
                }
                $cvCookies = $this->getCacheVaryCookies();
                foreach ( $cvCookies as $cookieName ) {
                        # Check for a simple string match, like the way squid does it
                        if ( strpos( $cookieHeader, $cookieName ) !== false ) {
                                wfDebug( __METHOD__ . ": found $cookieName\n" );
                                return true;
                        }
                }
                wfDebug( __METHOD__ . ": no cache-varying cookies found\n" );
                return false;
        }

        /**
         * Add an HTTP header that will influence on the cache
         *
         * @param $header String: header name
         * @param $option either an Array or null
         */
        public function addVaryHeader( $header, $option = null ) {
                if ( !array_key_exists( $header, $this->mVaryHeader ) ) {
                        $this->mVaryHeader[$header] = $option;
                } elseif( is_array( $option ) ) {
                        if( is_array( $this->mVaryHeader[$header] ) ) {
                                $this->mVaryHeader[$header] = array_merge( $this->mVaryHeader[$header], $option );
                        } else {
                                $this->mVaryHeader[$header] = $option;
                        }
                }
                $this->mVaryHeader[$header] = array_unique( $this->mVaryHeader[$header] );
        }

        /**
         * Get a complete X-Vary-Options header
         *
         * @return String
         */
        public function getXVO() {
                $cvCookies = $this->getCacheVaryCookies();

                $cookiesOption = array();
                foreach ( $cvCookies as $cookieName ) {
                        $cookiesOption[] = 'string-contains=' . $cookieName;
                }
                $this->addVaryHeader( 'Cookie', $cookiesOption );

                $headers = array();
                foreach( $this->mVaryHeader as $header => $option ) {
                        $newheader = $header;
                        if( is_array( $option ) ) {
                                $newheader .= ';' . implode( ';', $option );
                        }
                        $headers[] = $newheader;
                }
                $xvo = 'X-Vary-Options: ' . implode( ',', $headers );

                return $xvo;
        }

        /**
         * bug 21672: Add Accept-Language to Vary and XVO headers
         * if there's no 'variant' parameter existed in GET.
         *
         * For example:
         *   /w/index.php?title=Main_page should always be served; but
         *   /w/index.php?title=Main_page&variant=zh-cn should never be served.
         */
        function addAcceptLanguage() {
                global $wgRequest, $wgContLang;
                if( !$wgRequest->getCheck( 'variant' ) && $wgContLang->hasVariants() ) {
                        $variants = $wgContLang->getVariants();
                        $aloption = array();
                        foreach ( $variants as $variant ) {
                                if( $variant === $wgContLang->getCode() ) {
                                        continue;
                                } else {
                                        $aloption[] = 'string-contains=' . $variant;
                                        
                                        // IE and some other browsers use another form of language code
                                        // in their Accept-Language header, like "zh-CN" or "zh-TW".
                                        // We should handle these too.
                                        $ievariant = explode( '-', $variant );
                                        if ( count( $ievariant ) == 2 ) {
                                                $ievariant[1] = strtoupper( $ievariant[1] );
                                                $ievariant = implode( '-', $ievariant );
                                                $aloption[] = 'string-contains=' . $ievariant;
                                        }
                                }
                        }
                        $this->addVaryHeader( 'Accept-Language', $aloption );
                }
        }

        /**
         * Set a flag which will cause an X-Frame-Options header appropriate for 
         * edit pages to be sent. The header value is controlled by 
         * $wgEditPageFrameOptions.
         *
         * This is the default for special pages. If you display a CSRF-protected 
         * form on an ordinary view page, then you need to call this function.
         */
        public function preventClickjacking( $enable = true ) {
                $this->mPreventClickjacking = $enable;
        }

        /**
         * Turn off frame-breaking. Alias for $this->preventClickjacking(false).
         * This can be called from pages which do not contain any CSRF-protected
         * HTML form.
         */
        public function allowClickjacking() {
                $this->mPreventClickjacking = false;
        }

        /**
         * Get the X-Frame-Options header value (without the name part), or false 
         * if there isn't one. This is used by Skin to determine whether to enable 
         * JavaScript frame-breaking, for clients that don't support X-Frame-Options.
         */
        public function getFrameOptions() {
                global $wgBreakFrames, $wgEditPageFrameOptions;
                if ( $wgBreakFrames ) {
                        return 'DENY';
                } elseif ( $this->mPreventClickjacking && $wgEditPageFrameOptions ) {
                        return $wgEditPageFrameOptions;
                }
        }

        /**
         * Send cache control HTTP headers
         */
        public function sendCacheControl() {
                global $wgUseSquid, $wgUseESI, $wgUseETag, $wgSquidMaxage, $wgRequest, $wgUseXVO;

                $response = $wgRequest->response();
                if ( $wgUseETag && $this->mETag ) {
                        $response->header( "ETag: $this->mETag" );
                }

                $this->addAcceptLanguage();

                # don't serve compressed data to clients who can't handle it
                # maintain different caches for logged-in users and non-logged in ones
                $response->header( 'Vary: ' . join( ', ', array_keys( $this->mVaryHeader ) ) );

                if ( $wgUseXVO ) {
                        # Add an X-Vary-Options header for Squid with Wikimedia patches
                        $response->header( $this->getXVO() );
                }

                if( !$this->uncacheableBecauseRequestVars() && $this->mEnableClientCache ) {
                        if(
                                $wgUseSquid && session_id() == '' && !$this->isPrintable() &&
                                $this->mSquidMaxage != 0 && !$this->haveCacheVaryCookies()
                        )
                        {
                                if ( $wgUseESI ) {
                                        # We'll purge the proxy cache explicitly, but require end user agents
                                        # to revalidate against the proxy on each visit.
                                        # Surrogate-Control controls our Squid, Cache-Control downstream caches
                                        wfDebug( __METHOD__ . ": proxy caching with ESI; {$this->mLastModified} **\n", false );
                                        # start with a shorter timeout for initial testing
                                        # header( 'Surrogate-Control: max-age=2678400+2678400, content="ESI/1.0"');
                                        $response->header( 'Surrogate-Control: max-age='.$wgSquidMaxage.'+'.$this->mSquidMaxage.', content="ESI/1.0"');
                                        $response->header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
                                } else {
                                        # We'll purge the proxy cache for anons explicitly, but require end user agents
                                        # to revalidate against the proxy on each visit.
                                        # IMPORTANT! The Squid needs to replace the Cache-Control header with
                                        # Cache-Control: s-maxage=0, must-revalidate, max-age=0
                                        wfDebug( __METHOD__ . ": local proxy caching; {$this->mLastModified} **\n", false );
                                        # start with a shorter timeout for initial testing
                                        # header( "Cache-Control: s-maxage=2678400, must-revalidate, max-age=0" );
                                        $response->header( 'Cache-Control: s-maxage='.$this->mSquidMaxage.', must-revalidate, max-age=0' );
                                }
                        } else {
                                # We do want clients to cache if they can, but they *must* check for updates
                                # on revisiting the page.
                                wfDebug( __METHOD__ . ": private caching; {$this->mLastModified} **\n", false );
                                $response->header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', 0 ) . ' GMT' );
                                $response->header( "Cache-Control: private, must-revalidate, max-age=0" );
                        }
                        if($this->mLastModified) {
                                $response->header( "Last-Modified: {$this->mLastModified}" );
                        }
                } else {
                        wfDebug( __METHOD__ . ": no caching **\n", false );

                        # In general, the absence of a last modified header should be enough to prevent
                        # the client from using its cache. We send a few other things just to make sure.
                        $response->header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', 0 ) . ' GMT' );
                        $response->header( 'Cache-Control: no-cache, no-store, max-age=0, must-revalidate' );
                        $response->header( 'Pragma: no-cache' );
                }
        }

        /**
         * Get the message associed with the HTTP response code $code
         *
         * @param $code Integer: status code
         * @return String or null: message or null if $code is not in the list of
         *         messages
         */
        public static function getStatusMessage( $code ) {
                static $statusMessage = array(
                        100 => 'Continue',
                        101 => 'Switching Protocols',
                        102 => 'Processing',
                        200 => 'OK',
                        201 => 'Created',
                        202 => 'Accepted',
                        203 => 'Non-Authoritative Information',
                        204 => 'No Content',
                        205 => 'Reset Content',
                        206 => 'Partial Content',
                        207 => 'Multi-Status',
                        300 => 'Multiple Choices',
                        301 => 'Moved Permanently',
                        302 => 'Found',
                        303 => 'See Other',
                        304 => 'Not Modified',
                        305 => 'Use Proxy',
                        307 => 'Temporary Redirect',
                        400 => 'Bad Request',
                        401 => 'Unauthorized',
                        402 => 'Payment Required',
                        403 => 'Forbidden',
                        404 => 'Not Found',
                        405 => 'Method Not Allowed',
                        406 => 'Not Acceptable',
                        407 => 'Proxy Authentication Required',
                        408 => 'Request Timeout',
                        409 => 'Conflict',
                        410 => 'Gone',
                        411 => 'Length Required',
                        412 => 'Precondition Failed',
                        413 => 'Request Entity Too Large',
                        414 => 'Request-URI Too Large',
                        415 => 'Unsupported Media Type',
                        416 => 'Request Range Not Satisfiable',
                        417 => 'Expectation Failed',
                        422 => 'Unprocessable Entity',
                        423 => 'Locked',
                        424 => 'Failed Dependency',
                        500 => 'Internal Server Error',
                        501 => 'Not Implemented',
                        502 => 'Bad Gateway',
                        503 => 'Service Unavailable',
                        504 => 'Gateway Timeout',
                        505 => 'HTTP Version Not Supported',
                        507 => 'Insufficient Storage'
                );
                return isset( $statusMessage[$code] ) ? $statusMessage[$code] : null;
        }

        /**
         * Finally, all the text has been munged and accumulated into
         * the object, let's actually output it:
         */
        public function output() {
                global $wgUser, $wgOutputEncoding, $wgRequest;
                global $wgLanguageCode, $wgDebugRedirects, $wgMimeType;
                global $wgUseAjax, $wgAjaxWatch;
                global $wgEnableMWSuggest, $wgUniversalEditButton;

                if( $this->mDoNothing ) {
                        return;
                }
                wfProfileIn( __METHOD__ );
                if ( $this->mRedirect != '' ) {
                        # Standards require redirect URLs to be absolute
                        $this->mRedirect = wfExpandUrl( $this->mRedirect );
                        if( $this->mRedirectCode == '301' || $this->mRedirectCode == '303' ) {
                                if( !$wgDebugRedirects ) {
                                        $message = self::getStatusMessage( $this->mRedirectCode );
                                        $wgRequest->response()->header( "HTTP/1.1 {$this->mRedirectCode} $message" );
                                }
                                $this->mLastModified = wfTimestamp( TS_RFC2822 );
                        }
                        $this->sendCacheControl();

                        $wgRequest->response()->header( "Content-Type: text/html; charset=utf-8" );
                        if( $wgDebugRedirects ) {
                                $url = htmlspecialchars( $this->mRedirect );
                                print "<html>\n<head>\n<title>Redirect</title>\n</head>\n<body>\n";
                                print "<p>Location: <a href=\"$url\">$url</a></p>\n";
                                print "</body>\n</html>\n";
                        } else {
                                $wgRequest->response()->header( 'Location: ' . $this->mRedirect );
                        }
                        wfProfileOut( __METHOD__ );
                        return;
                } elseif ( $this->mStatusCode ) {
                        $message = self::getStatusMessage( $this->mStatusCode );
                        if ( $message ) {
                                $wgRequest->response()->header( 'HTTP/1.1 ' . $this->mStatusCode . ' ' . $message );
                        }
                }

                $sk = $wgUser->getSkin();

                // Add base resources
                $this->addModules( array( 'mediawiki.legacy.wikibits', 'mediawiki.util' ) );

                // Add various resources if required
                if ( $wgUseAjax ) {
                        $this->addModules( 'mediawiki.legacy.ajax' );

                        wfRunHooks( 'AjaxAddScript', array( &$this ) );

                        if( $wgAjaxWatch && $wgUser->isLoggedIn() ) {
                                $this->addModules( 'mediawiki.action.watch.ajax' );
                        }

                        if ( $wgEnableMWSuggest && !$wgUser->getOption( 'disablesuggest', false ) ) {
                                $this->addModules( 'mediawiki.legacy.mwsuggest' );
                        }
                }

                if( $wgUser->getBoolOption( 'editsectiononrightclick' ) ) {
                        $this->addModules( 'mediawiki.action.view.rightClickEdit' );
                }

                if( $wgUniversalEditButton ) {
                        if( $this->isArticleRelated() && $this->getTitle() && $this->getTitle()->quickUserCan( 'edit' )
                                && ( $this->getTitle()->exists() || $this->getTitle()->quickUserCan( 'create' ) ) ) {
                                // Original UniversalEditButton
                                $msg = wfMsg( 'edit' );
                                $this->addLink( array(
                                        'rel' => 'alternate',
                                        'type' => 'application/x-wiki',
                                        'title' => $msg,
                                        'href' => $this->getTitle()->getLocalURL( 'action=edit' )
                                ) );
                                // Alternate edit link
                                $this->addLink( array(
                                        'rel' => 'edit',
                                        'title' => $msg,
                                        'href' => $this->getTitle()->getLocalURL( 'action=edit' )
                                ) );
                        }
                }


                # Buffer output; final headers may depend on later processing
                ob_start();

                $wgRequest->response()->header( "Content-type: $wgMimeType; charset={$wgOutputEncoding}" );
                $wgRequest->response()->header( 'Content-language: ' . $wgLanguageCode );

                // Prevent framing, if requested
                $frameOptions = $this->getFrameOptions();
                if ( $frameOptions ) {
                        $wgRequest->response()->header( "X-Frame-Options: $frameOptions" );
                }

                if ( $this->mArticleBodyOnly ) {
                        $this->out( $this->mBodytext );
                } else {
                        // Hook that allows last minute changes to the output page, e.g.
                        // adding of CSS or Javascript by extensions.
                        wfRunHooks( 'BeforePageDisplay', array( &$this, &$sk ) );

                        wfProfileIn( 'Output-skin' );
                        $sk->outputPage( $this );
                        wfProfileOut( 'Output-skin' );
                }

                $this->sendCacheControl();
                ob_end_flush();
                wfProfileOut( __METHOD__ );
        }

        /**
         * Actually output something with print(). Performs an iconv to the
         * output encoding, if needed.
         *
         * @param $ins String: the string to output
         */
        public function out( $ins ) {
                global $wgInputEncoding, $wgOutputEncoding, $wgContLang;
                if ( 0 == strcmp( $wgInputEncoding, $wgOutputEncoding ) ) {
                        $outs = $ins;
                } else {
                        $outs = $wgContLang->iconv( $wgInputEncoding, $wgOutputEncoding, $ins );
                        if ( false === $outs ) {
                                $outs = $ins;
                        }
                }
                print $outs;
        }

        /**
         * Produce a "user is blocked" page.
         *
         * @param $return Boolean: whether to have a "return to $wgTitle" message or not.
         * @return nothing
         */
        function blockedPage( $return = true ) {
                global $wgUser, $wgContLang, $wgLang;

                $this->setPageTitle( wfMsg( 'blockedtitle' ) );
                $this->setRobotPolicy( 'noindex,nofollow' );
                $this->setArticleRelated( false );

                $name = User::whoIs( $wgUser->blockedBy() );
                $reason = $wgUser->blockedFor();
                if( $reason == '' ) {
                        $reason = wfMsg( 'blockednoreason' );
                }
                $blockTimestamp = $wgLang->timeanddate(
                        wfTimestamp( TS_MW, $wgUser->mBlock->mTimestamp ), true
                );
                $ip = wfGetIP();

                $link = '[[' . $wgContLang->getNsText( NS_USER ) . ":{$name}|{$name}]]";

                $blockid = $wgUser->mBlock->mId;

                $blockExpiry = $wgUser->mBlock->mExpiry;
                if ( $blockExpiry == 'infinity' ) {
                        // Entry in database (table ipblocks) is 'infinity' but 'ipboptions' uses 'infinite' or 'indefinite'
                        // Search for localization in 'ipboptions'
                        $scBlockExpiryOptions = wfMsg( 'ipboptions' );
                        foreach ( explode( ',', $scBlockExpiryOptions ) as $option ) {
                                if ( strpos( $option, ':' ) === false ) {
                                        continue;
                                }
                                list( $show, $value ) = explode( ':', $option );
                                if ( $value == 'infinite' || $value == 'indefinite' ) {
                                        $blockExpiry = $show;
                                        break;
                                }
                        }
                } else {
                        $blockExpiry = $wgLang->timeanddate(
                                wfTimestamp( TS_MW, $blockExpiry ),
                                true
                        );
                }

                if ( $wgUser->mBlock->mAuto ) {
                        $msg = 'autoblockedtext';
                } else {
                        $msg = 'blockedtext';
                }

                /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
                 * This could be a username, an IP range, or a single IP. */
                $intended = $wgUser->mBlock->mAddress;

                $this->addWikiMsg(
                        $msg, $link, $reason, $ip, $name, $blockid, $blockExpiry,
                        $intended, $blockTimestamp
                );

                # Don't auto-return to special pages
                if( $return ) {
                        $return = $this->getTitle()->getNamespace() > -1 ? $this->getTitle() : null;
                        $this->returnToMain( null, $return );
                }
        }

        /**
         * Output a standard error page
         *
         * @param $title String: message key for page title
         * @param $msg String: message key for page text
         * @param $params Array: message parameters
         */
        public function showErrorPage( $title, $msg, $params = array() ) {
                if ( $this->getTitle() ) {
                        $this->mDebugtext .= 'Original title: ' . $this->getTitle()->getPrefixedText() . "\n";
                }
                $this->setPageTitle( wfMsg( $title ) );
                $this->setHTMLTitle( wfMsg( 'errorpagetitle' ) );
                $this->setRobotPolicy( 'noindex,nofollow' );
                $this->setArticleRelated( false );
                $this->enableClientCache( false );
                $this->mRedirect = '';
                $this->mBodytext = '';

                $this->addWikiMsgArray( $msg, $params );

                $this->returnToMain();
        }

        /**
         * Output a standard permission error page
         *
         * @param $errors Array: error message keys
         * @param $action String: action that was denied or null if unknown
         */
        public function showPermissionsErrorPage( $errors, $action = null ) {
                $this->mDebugtext .= 'Original title: ' .
                $this->getTitle()->getPrefixedText() . "\n";
                $this->setPageTitle( wfMsg( 'permissionserrors' ) );
                $this->setHTMLTitle( wfMsg( 'permissionserrors' ) );
                $this->setRobotPolicy( 'noindex,nofollow' );
                $this->setArticleRelated( false );
                $this->enableClientCache( false );
                $this->mRedirect = '';
                $this->mBodytext = '';
                $this->addWikiText( $this->formatPermissionsErrorMessage( $errors, $action ) );
        }

        /**
         * Display an error page indicating that a given version of MediaWiki is
         * required to use it
         *
         * @param $version Mixed: the version of MediaWiki needed to use the page
         */
        public function versionRequired( $version ) {
                $this->setPageTitle( wfMsg( 'versionrequired', $version ) );
                $this->setHTMLTitle( wfMsg( 'versionrequired', $version ) );
                $this->setRobotPolicy( 'noindex,nofollow' );
                $this->setArticleRelated( false );
                $this->mBodytext = '';

                $this->addWikiMsg( 'versionrequiredtext', $version );
                $this->returnToMain();
        }

        /**
         * Display an error page noting that a given permission bit is required.
         *
         * @param $permission String: key required
         */
        public function permissionRequired( $permission ) {
                global $wgLang;

                $this->setPageTitle( wfMsg( 'badaccess' ) );
                $this->setHTMLTitle( wfMsg( 'errorpagetitle' ) );
                $this->setRobotPolicy( 'noindex,nofollow' );
                $this->setArticleRelated( false );
                $this->mBodytext = '';

                $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
                        User::getGroupsWithPermission( $permission ) );
                if( $groups ) {
                        $this->addWikiMsg(
                                'badaccess-groups',
                                $wgLang->commaList( $groups ),
                                count( $groups )
                        );
                } else {
                        $this->addWikiMsg( 'badaccess-group0' );
                }
                $this->returnToMain();
        }

        /**
         * Produce the stock "please login to use the wiki" page
         */
        public function loginToUse() {
                global $wgUser;

                if( $wgUser->isLoggedIn() ) {
                        $this->permissionRequired( 'read' );
                        return;
                }

                $skin = $wgUser->getSkin();

                $this->setPageTitle( wfMsg( 'loginreqtitle' ) );
                $this->setHtmlTitle( wfMsg( 'errorpagetitle' ) );
                $this->setRobotPolicy( 'noindex,nofollow' );
                $this->setArticleRelated( false );

                $loginTitle = SpecialPage::getTitleFor( 'Userlogin' );
                $loginLink = $skin->link(
                        $loginTitle,
                        wfMsgHtml( 'loginreqlink' ),
                        array(),
                        array( 'returnto' => $this->getTitle()->getPrefixedText() ),
                        array( 'known', 'noclasses' )
                );
                $this->addHTML( wfMsgWikiHtml( 'loginreqpagetext', $loginLink ) );
                $this->addHTML( "\n<!--" . $this->getTitle()->getPrefixedUrl() . '-->' );

                # Don't return to the main page if the user can't read it
                # otherwise we'll end up in a pointless loop
                $mainPage = Title::newMainPage();
                if( $mainPage->userCanRead() ) {
                        $this->returnToMain( null, $mainPage );
                }
        }

        /**
         * Format a list of error messages
         *
         * @param $errors An array of arrays returned by Title::getUserPermissionsErrors
         * @param $action String: action that was denied or null if unknown
         * @return String: the wikitext error-messages, formatted into a list.
         */
        public function formatPermissionsErrorMessage( $errors, $action = null ) {
                if ( $action == null ) {
                        $text = wfMsgNoTrans( 'permissionserrorstext', count( $errors ) ) . "\n\n";
                } else {
                        $action_desc = wfMsgNoTrans( "action-$action" );
                        $text = wfMsgNoTrans(
                                'permissionserrorstext-withaction',
                                count( $errors ),
                                $action_desc
                        ) . "\n\n";
                }

                if ( count( $errors ) > 1 ) {
                        $text .= '<ul class="permissions-errors">' . "\n";

                        foreach( $errors as $error ) {
                                $text .= '<li>';
                                $text .= call_user_func_array( 'wfMsgNoTrans', $error );
                                $text .= "</li>\n";
                        }
                        $text .= '</ul>';
                } else {
                        $text .= "<div class=\"permissions-errors\">\n" .
                                        call_user_func_array( 'wfMsgNoTrans', reset( $errors ) ) .
                                        "\n</div>";
                }

                return $text;
        }

        /**
         * Display a page stating that the Wiki is in read-only mode,
         * and optionally show the source of the page that the user
         * was trying to edit.  Should only be called (for this
         * purpose) after wfReadOnly() has returned true.
         *
         * For historical reasons, this function is _also_ used to
         * show the error message when a user tries to edit a page
         * they are not allowed to edit.  (Unless it's because they're
         * blocked, then we show blockedPage() instead.)  In this
         * case, the second parameter should be set to true and a list
         * of reasons supplied as the third parameter.
         *
         * @todo Needs to be split into multiple functions.
         *
         * @param $source    String: source code to show (or null).
         * @param $protected Boolean: is this a permissions error?
         * @param $reasons   Array: list of reasons for this error, as returned by Title::getUserPermissionsErrors().
         * @param $action    String: action that was denied or null if unknown
         */
        public function readOnlyPage( $source = null, $protected = false, $reasons = array(), $action = null ) {
                global $wgUser;
                $skin = $wgUser->getSkin();

                $this->setRobotPolicy( 'noindex,nofollow' );
                $this->setArticleRelated( false );

                // If no reason is given, just supply a default "I can't let you do
                // that, Dave" message.  Should only occur if called by legacy code.
                if ( $protected && empty( $reasons ) ) {
                        $reasons[] = array( 'badaccess-group0' );
                }

                if ( !empty( $reasons ) ) {
                        // Permissions error
                        if( $source ) {
                                $this->setPageTitle( wfMsg( 'viewsource' ) );
                                $this->setSubtitle(
                                        wfMsg( 'viewsourcefor', $skin->linkKnown( $this->getTitle() ) )
                                );
                        } else {
                                $this->setPageTitle( wfMsg( 'badaccess' ) );
                        }
                        $this->addWikiText( $this->formatPermissionsErrorMessage( $reasons, $action ) );
                } else {
                        // Wiki is read only
                        $this->setPageTitle( wfMsg( 'readonly' ) );
                        $reason = wfReadOnlyReason();
                        $this->wrapWikiMsg( "<div class='mw-readonly-error'>\n$1\n</div>", array( 'readonlytext', $reason ) );
                }

                // Show source, if supplied
                if( is_string( $source ) ) {
                        $this->addWikiMsg( 'viewsourcetext' );

                        $params = array(
                                'id'   => 'wpTextbox1',
                                'name' => 'wpTextbox1',
                                'cols' => $wgUser->getOption( 'cols' ),
                                'rows' => $wgUser->getOption( 'rows' ),
                                'readonly' => 'readonly'
                        );
                        $this->addHTML( Html::element( 'textarea', $params, $source ) );

                        // Show templates used by this article
                        $skin = $wgUser->getSkin();
                        $article = new Article( $this->getTitle() );
                        $this->addHTML( "<div class='templatesUsed'>
{$skin->formatTemplates( $article->getUsedTemplates() )}
</div>
" );
                }

                # If the title doesn't exist, it's fairly pointless to print a return
                # link to it.  After all, you just tried editing it and couldn't, so
                # what's there to do there?
                if( $this->getTitle()->exists() ) {
                        $this->returnToMain( null, $this->getTitle() );
                }
        }

        /**
         * Adds JS-based password security checker
         * @param $passwordId String ID of input box containing password
         * @param $retypeId String ID of input box containing retyped password
         * @return none
         */
        public function addPasswordSecurity( $passwordId, $retypeId ) {
                $data = array(
                        'password' => '#' . $passwordId,
                        'retype' => '#' . $retypeId,
                        'messages' => array(),
                );
                foreach ( array( 'password-strength', 'password-strength-bad', 'password-strength-mediocre',
                                'password-strength-acceptable', 'password-strength-good', 'password-retype', 'password-retype-mismatch'
                        ) as $message ) {
                        $data['messages'][$message] = wfMsg( $message );
                }
                $this->addScript( Html::inlineScript( 'var passwordSecurity=' . FormatJson::encode( $data ) ) );
                $this->addModules( 'mediawiki.legacy.password' );
        }

        public function showFatalError( $message ) {
                $this->setPageTitle( wfMsg( 'internalerror' ) );
                $this->setRobotPolicy( 'noindex,nofollow' );
                $this->setArticleRelated( false );
                $this->enableClientCache( false );
                $this->mRedirect = '';
                $this->mBodytext = $message;
        }

        public function showUnexpectedValueError( $name, $val ) {
                $this->showFatalError( wfMsg( 'unexpected', $name, $val ) );
        }

        public function showFileCopyError( $old, $new ) {
                $this->showFatalError( wfMsg( 'filecopyerror', $old, $new ) );
        }

        public function showFileRenameError( $old, $new ) {
                $this->showFatalError( wfMsg( 'filerenameerror', $old, $new ) );
        }

        public function showFileDeleteError( $name ) {
                $this->showFatalError( wfMsg( 'filedeleteerror', $name ) );
        }

        public function showFileNotFoundError( $name ) {
                $this->showFatalError( wfMsg( 'filenotfound', $name ) );
        }

        /**
         * Add a "return to" link pointing to a specified title
         *
         * @param $title Title to link
         * @param $query String: query string
         * @param $text String text of the link (input is not escaped)
         */
        public function addReturnTo( $title, $query = array(), $text = null ) {
                global $wgUser;
                $this->addLink( array( 'rel' => 'next', 'href' => $title->getFullURL() ) );
                $link = wfMsgHtml(
                        'returnto',
                        $wgUser->getSkin()->link( $title, $text, array(), $query )
                );
                $this->addHTML( "<p id=\"mw-returnto\">{$link}</p>\n" );
        }

        /**
         * Add a "return to" link pointing to a specified title,
         * or the title indicated in the request, or else the main page
         *
         * @param $unused No longer used
         * @param $returnto Title or String to return to
         * @param $returntoquery String: query string for the return to link
         */
        public function returnToMain( $unused = null, $returnto = null, $returntoquery = null ) {
                global $wgRequest;

                if ( $returnto == null ) {
                        $returnto = $wgRequest->getText( 'returnto' );
                }

                if ( $returntoquery == null ) {
                        $returntoquery = $wgRequest->getText( 'returntoquery' );
                }

                if ( $returnto === '' ) {
                        $returnto = Title::newMainPage();
                }

                if ( is_object( $returnto ) ) {
                        $titleObj = $returnto;
                } else {
                        $titleObj = Title::newFromText( $returnto );
                }
                if ( !is_object( $titleObj ) ) {
                        $titleObj = Title::newMainPage();
                }

                $this->addReturnTo( $titleObj, $returntoquery );
        }

        /**
         * @param $sk Skin The given Skin
         * @param $includeStyle Boolean: unused
         * @return String: The doctype, opening <html>, and head element.
         */
        public function headElement( Skin $sk, $includeStyle = true ) {
                global $wgOutputEncoding, $wgMimeType;
                global $wgUseTrackbacks, $wgHtml5;
                global $wgUser, $wgRequest, $wgLang;

                if ( $sk->commonPrintStylesheet() ) {
                        $this->addModuleStyles( 'mediawiki.legacy.wikiprintable' );
                }
                $sk->setupUserCss( $this );

                $ret = Html::htmlHeader( array( 'lang' => wfUILang()->getCode() ) );

                if ( $this->getHTMLTitle() == '' ) {
                        $this->setHTMLTitle( wfMsg( 'pagetitle', $this->getPageTitle() ) );
                }

                $openHead = Html::openElement( 'head' );
                if ( $openHead ) {
                        # Don't bother with the newline if $head == ''
                        $ret .= "$openHead\n";
                }

                if ( $wgHtml5 ) {
                        # More succinct than <meta http-equiv=Content-Type>, has the
                        # same effect
                        $ret .= Html::element( 'meta', array( 'charset' => $wgOutputEncoding ) ) . "\n";
                } else {
                        $this->addMeta( 'http:Content-Type', "$wgMimeType; charset=$wgOutputEncoding" );
                }

                $ret .= Html::element( 'title', null, $this->getHTMLTitle() ) . "\n";

                $ret .= implode( "\n", array(
                        $this->getHeadLinks( $sk ),
                        $this->buildCssLinks( $sk ),
                        $this->getHeadItems()
                ) );

                if ( $wgUseTrackbacks && $this->isArticleRelated() ) {
                        $ret .= $this->getTitle()->trackbackRDF();
                }

                $closeHead = Html::closeElement( 'head' );
                if ( $closeHead ) {
                        $ret .= "$closeHead\n";
                }

                $bodyAttrs = array();

                # Crazy edit-on-double-click stuff
                $action = $wgRequest->getVal( 'action', 'view' );

                if (
                        $this->getTitle()->getNamespace() != NS_SPECIAL &&
                        !in_array( $action, array( 'edit', 'submit' ) ) &&
                        $wgUser->getOption( 'editondblclick' )
                )
                {
                        $bodyAttrs['ondblclick'] = "document.location = '" . Xml::escapeJsString( $this->getTitle()->getEditURL() ) . "'";
                }

                # Class bloat
                $dir = wfUILang()->getDir();
                $bodyAttrs['class'] = "mediawiki $dir";

                if ( $wgLang->capitalizeAllNouns() ) {
                        # A <body> class is probably not the best way to do this . . .
                        $bodyAttrs['class'] .= ' capitalize-all-nouns';
                }
                $bodyAttrs['class'] .= ' ns-' . $this->getTitle()->getNamespace();
                if ( $this->getTitle()->getNamespace() == NS_SPECIAL ) {
                        $bodyAttrs['class'] .= ' ns-special';
                } elseif ( $this->getTitle()->isTalkPage() ) {
                        $bodyAttrs['class'] .= ' ns-talk';
                } else {
                        $bodyAttrs['class'] .= ' ns-subject';
                }
                $bodyAttrs['class'] .= ' ' . Sanitizer::escapeClass( 'page-' . $this->getTitle()->getPrefixedText() );
                $bodyAttrs['class'] .= ' skin-' . Sanitizer::escapeClass( $wgUser->getSkin()->getSkinName() );

                $sk->addToBodyAttributes( $this, $bodyAttrs ); // Allow skins to add body attributes they need
                wfRunHooks( 'OutputPageBodyAttributes', array( $this, $sk, &$bodyAttrs ) );

                $ret .= Html::openElement( 'body', $bodyAttrs ) . "\n";

                return $ret;
        }

        /**
         * Get a ResourceLoader object associated with this OutputPage
         */
        public function getResourceLoader() {
                if ( is_null( $this->mResourceLoader ) ) {
                        $this->mResourceLoader = new ResourceLoader();
                }
                return $this->mResourceLoader;
        }               

        /**
         * TODO: Document
         * @param $skin Skin
         * @param $modules Array/string with the module name
         * @param $only string May be styles, messages or scripts
         * @param $useESI boolean
         * @return string html <script> and <style> tags
         */
        protected function makeResourceLoaderLink( Skin $skin, $modules, $only, $useESI = false ) {
                global $wgUser, $wgLang, $wgLoadScript, $wgResourceLoaderUseESI,
                        $wgResourceLoaderInlinePrivateModules, $wgRequest;
                // Lazy-load ResourceLoader
                // TODO: Should this be a static function of ResourceLoader instead?
                // TODO: Divide off modules starting with "user", and add the user parameter to them
                $query = array(
                        'lang' => $wgLang->getCode(),
                        'debug' => ResourceLoader::inDebugMode() ? 'true' : 'false',
                        'skin' => $skin->getSkinName(),
                        'only' => $only,
                );
                // Propagate printable and handheld parameters if present
                if ( $wgRequest->getBool( 'printable' ) ) {
                        $query['printable'] = 1;
                }
                if ( $wgRequest->getBool( 'handheld' ) ) {
                        $query['handheld'] = 1;
                }
                
                if ( !count( $modules ) ) {
                        return '';
                }
                
                if ( count( $modules ) > 1 ) {
                        // Remove duplicate module requests
                        $modules = array_unique( (array) $modules );
                        // Sort module names so requests are more uniform
                        sort( $modules );
                
                        if ( ResourceLoader::inDebugMode() ) {
                                // Recursively call us for every item
                                $links = '';
                                foreach ( $modules as $name ) {
                                        $links .= $this->makeResourceLoaderLink( $skin, $name, $only, $useESI );
                                }
                                return $links;
                        }
                }
                
                // Create keyed-by-group list of module objects from modules list
                $groups = array();
                $resourceLoader = $this->getResourceLoader();
                foreach ( (array) $modules as $name ) {
                        $module = $resourceLoader->getModule( $name );
                        $group = $module->getGroup();
                        if ( !isset( $groups[$group] ) ) {
                                $groups[$group] = array();
                        }
                        $groups[$group][$name] = $module;
                }
                $links = '';
                foreach ( $groups as $group => $modules ) {
                        $query['modules'] = implode( '|', array_keys( $modules ) );
                        // Special handling for user-specific groups
                        if ( ( $group === 'user' || $group === 'private' ) && $wgUser->isLoggedIn() ) {
                                $query['user'] = $wgUser->getName();
                        }
                        // Support inlining of private modules if configured as such
                        if ( $group === 'private' && $wgResourceLoaderInlinePrivateModules ) {
                                $context = new ResourceLoaderContext( $resourceLoader, new FauxRequest( $query ) );
                                if ( $only == 'styles' ) {
                                        $links .= Html::inlineStyle(
                                                $resourceLoader->makeModuleResponse( $context, $modules )
                                        );
                                } else {
                                        $links .= Html::inlineScript(
                                                ResourceLoader::makeLoaderConditionalScript(
                                                        $resourceLoader->makeModuleResponse( $context, $modules )
                                                )
                                        );
                                }
                                continue;
                        }
                        // Special handling for user and site groups; because users might change their stuff
                        // on-wiki like site or user pages, or user preferences; we need to find the highest
                        // timestamp of these user-changable modules so we can ensure cache misses on change
                        if ( $group === 'user' || $group === 'site' ) {
                                // Create a fake request based on the one we are about to make so modules return
                                // correct times
                                $context = new ResourceLoaderContext( $resourceLoader, new FauxRequest( $query ) );
                                // Get the maximum timestamp
                                $timestamp = 1;
                                foreach ( $modules as $module ) {
                                        $timestamp = max( $timestamp, $module->getModifiedTime( $context ) );
                                }
                                // Add a version parameter so cache will break when things change
                                $query['version'] = wfTimestamp( TS_ISO_8601_BASIC, round( $timestamp, -2 ) );
                        }
                        // Make queries uniform in order
                        ksort( $query );

                        $url = wfAppendQuery( $wgLoadScript, $query );
                        if ( $useESI && $wgResourceLoaderUseESI ) {
                                $esi = Xml::element( 'esi:include', array( 'src' => $url ) );
                                if ( $only == 'styles' ) {
                                        $links .= Html::inlineStyle( $esi );
                                } else {
                                        $links .= Html::inlineScript( $esi );
                                }
                        } else {
                                // Automatically select style/script elements
                                if ( $only === 'styles' ) {
                                        $links .= Html::linkedStyle( wfAppendQuery( $wgLoadScript, $query ) ) . "\n";
                                } else {
                                        $links .= Html::linkedScript( wfAppendQuery( $wgLoadScript, $query ) ) . "\n";
                                }
                        }
                }
                return $links;
        }

        /**
         * Gets the global variables and mScripts; also adds userjs to the end if
         * enabled. Despite the name, these scripts are no longer put in the
         * <head> but at the bottom of the <body>
         *
         * @param $sk Skin object to use
         * @return String: HTML fragment
         */
        function getHeadScripts( Skin $sk ) {
                global $wgUser, $wgRequest, $wgUseSiteJs;

                // Startup - this will immediately load jquery and mediawiki modules
                $scripts = $this->makeResourceLoaderLink( $sk, 'startup', 'scripts', true );

                // Configuration -- This could be merged together with the load and go, but
                // makeGlobalVariablesScript returns a whole script tag -- grumble grumble...
                $scripts .= Skin::makeGlobalVariablesScript( $sk->getSkinName() ) . "\n";

                // Script and Messages "only" requests
                $scripts .= $this->makeResourceLoaderLink( $sk, $this->getModuleScripts(), 'scripts' );
                $scripts .= $this->makeResourceLoaderLink( $sk, $this->getModuleMessages(), 'messages' );

                // Modules requests - let the client calculate dependencies and batch requests as it likes
                if ( $this->getModules() ) {
                        $scripts .= Html::inlineScript(
                                ResourceLoader::makeLoaderConditionalScript(
                                        Xml::encodeJsCall( 'mediaWiki.loader.load', array( $this->getModules() ) ) .
                                        Xml::encodeJsCall( 'mediaWiki.loader.go', array() )
                                )
                        ) . "\n";
                }

                // Legacy Scripts
                $scripts .= "\n" . $this->mScripts;

                // Add site JS if enabled
                if ( $wgUseSiteJs ) {
                        $scripts .= $this->makeResourceLoaderLink( $sk, 'site', 'scripts' );
                }

                // Add user JS if enabled - trying to load user.options as a bundle if possible
                $userOptionsAdded = false;
                if ( $this->isUserJsAllowed() && $wgUser->isLoggedIn() ) {
                        $action = $wgRequest->getVal( 'action', 'view' );
                        if( $this->mTitle && $this->mTitle->isJsSubpage() && $sk->userCanPreview( $action ) ) {
                                # XXX: additional security check/prompt?
                                $scripts .= Html::inlineScript( "\n" . $wgRequest->getText( 'wpTextbox1' ) . "\n" ) . "\n";
                        } else {
                                $scripts .= $this->makeResourceLoaderLink(
                                        $sk, array( 'user', 'user.options' ), 'scripts'
                                );
                                $userOptionsAdded = true;
                        }
                }
                if ( !$userOptionsAdded ) {
                        $scripts .= $this->makeResourceLoaderLink( $sk, 'user.options', 'scripts' );
                }
                
                return $scripts;
        }

        /**
         * Add default \<meta\> tags
         */
        protected function addDefaultMeta() {
                global $wgVersion, $wgHtml5;

                static $called = false;
                if ( $called ) {
                        # Don't run this twice
                        return;
                }
                $called = true;

                if ( !$wgHtml5 ) {
                        $this->addMeta( 'http:Content-Style-Type', 'text/css' ); // bug 15835
                }
                $this->addMeta( 'generator', "MediaWiki $wgVersion" );

                $p = "{$this->mIndexPolicy},{$this->mFollowPolicy}";
                if( $p !== 'index,follow' ) {
                        // http://www.robotstxt.org/wc/meta-user.html
                        // Only show if it's different from the default robots policy
                        $this->addMeta( 'robots', $p );
                }

                if ( count( $this->mKeywords ) > 0 ) {
                        $strip = array(
                                "/<.*?" . ">/" => '',
                                "/_/" => ' '
                        );
                        $this->addMeta(
                                'keywords',
                                preg_replace(
                                        array_keys( $strip ),
                                        array_values( $strip ),
                                        implode( ',', $this->mKeywords )
                                )
                        );
                }
        }

        /**
         * @return string HTML tag links to be put in the header.
         */
        public function getHeadLinks( Skin $sk ) {
                global $wgFeed;

                // Ideally this should happen earlier, somewhere. :P
                $this->addDefaultMeta();

                $tags = array();

                foreach ( $this->mMetatags as $tag ) {
                        if ( 0 == strcasecmp( 'http:', substr( $tag[0], 0, 5 ) ) ) {
                                $a = 'http-equiv';
                                $tag[0] = substr( $tag[0], 5 );
                        } else {
                                $a = 'name';
                        }
                        $tags[] = Html::element( 'meta',
                                array(
                                        $a => $tag[0],
                                        'content' => $tag[1]
                                )
                        );
                }
                foreach ( $this->mLinktags as $tag ) {
                        $tags[] = Html::element( 'link', $tag );
                }

                if( $wgFeed ) {
                        foreach( $this->getSyndicationLinks() as $format => $link ) {
                                # Use the page name for the title (accessed through $wgTitle since
                                # there's no other way).  In principle, this could lead to issues
                                # with having the same name for different feeds corresponding to
                                # the same page, but we can't avoid that at this low a level.

                                $tags[] = $this->feedLink(
                                        $format,
                                        $link,
                                        # Used messages: 'page-rss-feed' and 'page-atom-feed' (for an easier grep)
                                        wfMsg( "page-{$format}-feed", $this->getTitle()->getPrefixedText() )
                                );
                        }

                        # Recent changes feed should appear on every page (except recentchanges,
                        # that would be redundant). Put it after the per-page feed to avoid
                        # changing existing behavior. It's still available, probably via a
                        # menu in your browser. Some sites might have a different feed they'd
                        # like to promote instead of the RC feed (maybe like a "Recent New Articles"
                        # or "Breaking news" one). For this, we see if $wgOverrideSiteFeed is defined.
                        # If so, use it instead.

                        global $wgOverrideSiteFeed, $wgSitename, $wgAdvertisedFeedTypes;
                        $rctitle = SpecialPage::getTitleFor( 'Recentchanges' );

                        if ( $wgOverrideSiteFeed ) {
                                foreach ( $wgOverrideSiteFeed as $type => $feedUrl ) {
                                        $tags[] = $this->feedLink(
                                                $type,
                                                htmlspecialchars( $feedUrl ),
                                                wfMsg( "site-{$type}-feed", $wgSitename )
                                        );
                                }
                        } elseif ( $this->getTitle()->getPrefixedText() != $rctitle->getPrefixedText() ) {
                                foreach ( $wgAdvertisedFeedTypes as $format ) {
                                        $tags[] = $this->feedLink(
                                                $format,
                                                $rctitle->getLocalURL( "feed={$format}" ),
                                                wfMsg( "site-{$format}-feed", $wgSitename ) # For grep: 'site-rss-feed', 'site-atom-feed'.
                                        );
                                }
                        }
                }
                return implode( "\n", $tags );
        }

        /**
         * Generate a <link rel/> for a feed.
         *
         * @param $type String: feed type
         * @param $url String: URL to the feed
         * @param $text String: value of the "title" attribute
         * @return String: HTML fragment
         */
        private function feedLink( $type, $url, $text ) {
                return Html::element( 'link', array(
                        'rel' => 'alternate',
                        'type' => "application/$type+xml",
                        'title' => $text,
                        'href' => $url )
                );
        }

        /**
         * Add a local or specified stylesheet, with the given media options.
         * Meant primarily for internal use...
         *
         * @param $style String: URL to the file
         * @param $media String: to specify a media type, 'screen', 'printable', 'handheld' or any.
         * @param $condition String: for IE conditional comments, specifying an IE version
         * @param $dir String: set to 'rtl' or 'ltr' for direction-specific sheets
         */
        public function addStyle( $style, $media = '', $condition = '', $dir = '' ) {
                $options = array();
                // Even though we expect the media type to be lowercase, but here we
                // force it to lowercase to be safe.
                if( $media ) {
                        $options['media'] = $media;
                }
                if( $condition ) {
                        $options['condition'] = $condition;
                }
                if( $dir ) {
                        $options['dir'] = $dir;
                }
                $this->styles[$style] = $options;
        }

        /**
         * Adds inline CSS styles
         * @param $style_css Mixed: inline CSS
         */
        public function addInlineStyle( $style_css ){
                $this->mInlineStyles .= Html::inlineStyle( $style_css );
        }

        /**
         * Build a set of <link>s for the stylesheets specified in the $this->styles array.
         * These will be applied to various media & IE conditionals.
         * @param $sk Skin object
         */
        public function buildCssLinks( $sk ) {
                $ret = '';
                // Add ResourceLoader styles
                // Split the styles into three groups
                $styles = array( 'other' => array(), 'user' => array(), 'site' => array() );
                $resourceLoader = $this->getResourceLoader();
                foreach ( $this->getModuleStyles() as $name ) {
                        $group = $resourceLoader->getModule( $name )->getGroup();
                        // Modules in groups named "other" or anything different than "user" or "site" will
                        // be placed in the "other" group
                        $styles[isset( $styles[$group] ) ? $group : 'other'][] = $name;
                }

                // We want site and user styles to override dynamically added styles from modules, but we want
                // dynamically added styles to override statically added styles from other modules. So the order
                // has to be other, dynamic, site, user
                // Add statically added styles for other modules
                $ret .= $this->makeResourceLoaderLink( $sk, $styles['other'], 'styles' );
                // Add normal styles added through addStyle()/addInlineStyle() here
                $ret .= implode( "\n", $this->buildCssLinksArray() ) . $this->mInlineStyles;
                // Add marker tag to mark the place where the client-side loader should inject dynamic styles
                // We use a <meta> tag with a made-up name for this because that's valid HTML
                $ret .= Html::element( 'meta', array( 'name' => 'ResourceLoaderDynamicStyles', 'content' => '' ) );
                // Add site and user styles
                $ret .= $this->makeResourceLoaderLink(
                        $sk, array_merge( $styles['site'], $styles['user'] ), 'styles'
                );
                return $ret;
        }

        public function buildCssLinksArray() {
                $links = array();
                foreach( $this->styles as $file => $options ) {
                        $link = $this->styleLink( $file, $options );
                        if( $link ) {
                                $links[$file] = $link;
                        }
                }
                return $links;
        }

        /**
         * Generate \<link\> tags for stylesheets
         *
         * @param $style String: URL to the file
         * @param $options Array: option, can contain 'condition', 'dir', 'media'
         *                 keys
         * @return String: HTML fragment
         */
        protected function styleLink( $style, $options ) {
                if( isset( $options['dir'] ) ) {
                        $siteDir = wfUILang()->getDir();
                        if( $siteDir != $options['dir'] ) {
                                return '';
                        }
                }

                if( isset( $options['media'] ) ) {
                        $media = self::transformCssMedia( $options['media'] );
                        if( is_null( $media ) ) {
                                return '';
                        }
                } else {
                        $media = 'all';
                }

                if( substr( $style, 0, 1 ) == '/' ||
                        substr( $style, 0, 5 ) == 'http:' ||
                        substr( $style, 0, 6 ) == 'https:' ) {
                        $url = $style;
                } else {
                        global $wgStylePath, $wgStyleVersion;
                        $url = $wgStylePath . '/' . $style . '?' . $wgStyleVersion;
                }

                $link = Html::linkedStyle( $url, $media );

                if( isset( $options['condition'] ) ) {
                        $condition = htmlspecialchars( $options['condition'] );
                        $link = "<!--[if $condition]>$link<![endif]-->";
                }
                return $link;
        }

        /**
         * Transform "media" attribute based on request parameters
         *
         * @param $media String: current value of the "media" attribute
         * @return String: modified value of the "media" attribute
         */
        public static function transformCssMedia( $media ) {
                global $wgRequest, $wgHandheldForIPhone;

                // Switch in on-screen display for media testing
                $switches = array(
                        'printable' => 'print',
                        'handheld' => 'handheld',
                );
                foreach( $switches as $switch => $targetMedia ) {
                        if( $wgRequest->getBool( $switch ) ) {
                                if( $media == $targetMedia ) {
                                        $media = '';
                                } elseif( $media == 'screen' ) {
                                        return null;
                                }
                        }
                }

                // Expand longer media queries as iPhone doesn't grok 'handheld'
                if( $wgHandheldForIPhone ) {
                        $mediaAliases = array(
                                'screen' => 'screen and (min-device-width: 481px)',
                                'handheld' => 'handheld, only screen and (max-device-width: 480px)',
                        );

                        if( isset( $mediaAliases[$media] ) ) {
                                $media = $mediaAliases[$media];
                        }
                }

                return $media;
        }

        /**
         * Turn off regular page output and return an error reponse
         * for when rate limiting has triggered.
         */
        public function rateLimited() {
                $this->setPageTitle( wfMsg( 'actionthrottled' ) );
                $this->setRobotPolicy( 'noindex,follow' );
                $this->setArticleRelated( false );
                $this->enableClientCache( false );
                $this->mRedirect = '';
                $this->clearHTML();
                $this->setStatusCode( 503 );
                $this->addWikiMsg( 'actionthrottledtext' );

                $this->returnToMain( null, $this->getTitle() );
        }

        /**
         * Show a warning about slave lag
         *
         * If the lag is higher than $wgSlaveLagCritical seconds,
         * then the warning is a bit more obvious. If the lag is
         * lower than $wgSlaveLagWarning, then no warning is shown.
         *
         * @param $lag Integer: slave lag
         */
        public function showLagWarning( $lag ) {
                global $wgSlaveLagWarning, $wgSlaveLagCritical, $wgLang;
                if( $lag >= $wgSlaveLagWarning ) {
                        $message = $lag < $wgSlaveLagCritical
                                ? 'lag-warn-normal'
                                : 'lag-warn-high';
                        $wrap = Html::rawElement( 'div', array( 'class' => "mw-{$message}" ), "\n$1\n" );
                        $this->wrapWikiMsg( "$wrap\n", array( $message, $wgLang->formatNum( $lag ) ) );
                }
        }

        /**
         * Add a wikitext-formatted message to the output.
         * This is equivalent to:
         *
         *    $wgOut->addWikiText( wfMsgNoTrans( ... ) )
         */
        public function addWikiMsg( /*...*/ ) {
                $args = func_get_args();
                $name = array_shift( $args );
                $this->addWikiMsgArray( $name, $args );
        }

        /**
         * Add a wikitext-formatted message to the output.
         * Like addWikiMsg() except the parameters are taken as an array
         * instead of a variable argument list.
         *
         * $options is passed through to wfMsgExt(), see that function for details.
         */
        public function addWikiMsgArray( $name, $args, $options = array() ) {
                $options[] = 'parse';
                $text = wfMsgExt( $name, $options, $args );
                $this->addHTML( $text );
        }

        /**
         * This function takes a number of message/argument specifications, wraps them in
         * some overall structure, and then parses the result and adds it to the output.
         *
         * In the $wrap, $1 is replaced with the first message, $2 with the second, and so
         * on. The subsequent arguments may either be strings, in which case they are the
         * message names, or arrays, in which case the first element is the message name,
         * and subsequent elements are the parameters to that message.
         *
         * The special named parameter 'options' in a message specification array is passed
         * through to the $options parameter of wfMsgExt().
         *
         * Don't use this for messages that are not in users interface language.
         *
         * For example:
         *
         *    $wgOut->wrapWikiMsg( "<div class='error'>\n$1\n</div>", 'some-error' );
         *
         * Is equivalent to:
         *
         *    $wgOut->addWikiText( "<div class='error'>\n" . wfMsgNoTrans( 'some-error' ) . "\n</div>" );
         *
         * The newline after opening div is needed in some wikitext. See bug 19226.
         */
        public function wrapWikiMsg( $wrap /*, ...*/ ) {
                $msgSpecs = func_get_args();
                array_shift( $msgSpecs );
                $msgSpecs = array_values( $msgSpecs );
                $s = $wrap;
                foreach ( $msgSpecs as $n => $spec ) {
                        $options = array();
                        if ( is_array( $spec ) ) {
                                $args = $spec;
                                $name = array_shift( $args );
                                if ( isset( $args['options'] ) ) {
                                        $options = $args['options'];
                                        unset( $args['options'] );
                                }
                        }  else {
                                $args = array();
                                $name = $spec;
                        }
                        $s = str_replace( '$' . ( $n + 1 ), wfMsgExt( $name, $options, $args ), $s );
                }
                $this->addHTML( $this->parse( $s, /*linestart*/true, /*uilang*/true ) );
        }

        /**
         * Include jQuery core. Use this to avoid loading it multiple times
         * before we get a usable script loader.
         *
         * @param $modules Array: list of jQuery modules which should be loaded
         * @return Array: the list of modules which were not loaded.
         * @since 1.16
         * @deprecated @since 1.17
         */
        public function includeJQuery( $modules = array() ) {
                return array();
        }

}