path: root/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 = '', $mDebugtext = '';
	var $mHTMLtitle = '', $mIsarticle = true, $mPrintable = false;
	var $mSubtitle = '', $mRedirect = '', $mStatusCode;
	var $mLastModified = '', $mETag = false;
	var $mCategoryLinks = array(), $mLanguageLinks = array();
	var $mScripts = '', $mLinkColours, $mPageLinkTitle = '', $mHeadItems = array();
	var $mTemplateIds = array();

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

	var $mNewSectionLink = false;
	var $mNoGallery = false;
	var $mPageTitleActionText = '';
	var $mParseWarnings = array();
	var $mSquidMaxage = 0;
	var $mRevisionId = 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();

	private $mIndexPolicy = 'index';
	private $mFollowPolicy = 'follow';

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

	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;
	}

	public function getRedirect() {
		return $this->mRedirect;
	}

	/**
	 * Set the HTTP status code to send with the output.
	 *
	 * @param int $statusCode
	 * @return nothing
	 */
	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 ) );
	}

	function addKeyword( $text ) { array_push( $this->mKeywords, $text ); }
	function addScript( $script ) { $this->mScripts .= "\t\t".$script; }
	
	function addExtensionStyle( $url ) {
		$linkarr = array( 'rel' => 'stylesheet', 'href' => $url, 'type' => 'text/css' );
		array_push( $this->mExtStyles, $linkarr );
	}

	/**
	 * Add a JavaScript file out of skins/common, or a given relative path.
	 * @param string $file filename in skins/common or complete on-server path (/foo/bar.js)
	 */
	function addScriptFile( $file ) {
		global $wgStylePath, $wgStyleVersion, $wgJsMimeType;
		if( substr( $file, 0, 1 ) == '/' ) {
			$path = $file;
		} else {
			$path =  "{$wgStylePath}/common/{$file}";
		}
		$this->addScript( "<script type=\"{$wgJsMimeType}\" src=\"$path?$wgStyleVersion\"></script>\n" );
	}
	
	/**
	 * Add a self-contained script tag with the given contents
	 * @param string $script JavaScript text, no <script> tags
	 */
	function addInlineScript( $script ) {
		global $wgJsMimeType;
		$this->mScripts .= "<script type=\"$wgJsMimeType\">/*<![CDATA[*/\n$script\n/*]]>*/</script>";
	}

	function getScript() {
		return $this->mScripts . $this->getHeadItems();
	}

	function getHeadItems() {
		$s = '';
		foreach ( $this->mHeadItems as $item ) {
			$s .= $item;
		}
		return $s;
	}

	function addHeadItem( $name, $value ) {
		$this->mHeadItems[$name] = $value;
	}

	function hasHeadItem( $name ) {
		return isset( $this->mHeadItems[$name] );
	}

	function setETag($tag) { $this->mETag = $tag; }
	function setArticleBodyOnly($only) { $this->mArticleBodyOnly = $only; }
	function getArticleBodyOnly($only) { return $this->mArticleBodyOnly; }

	function addLink( $linkarr ) {
		# $linkarr should be an associative array of attributes. We'll escape on output.
		array_push( $this->mLinktags, $linkarr );
	}
	
	# Get all links added by extensions
	function getExtStyle() {
		return $this->mExtStyles;
	}

	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;
	}

	/**
	 * 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 bool True iff cache-ok headers was sent.
	 */
	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 );
		$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;
	}

	function setPageTitleActionText( $text ) {
		$this->mPageTitleActionText = $text;
	}

	function getPageTitleActionText () {
		if ( isset( $this->mPageTitleActionText ) ) {
			return $this->mPageTitleActionText;
		}
	}

	/**
	 * 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 = explode( ',', $policy );
		$policy = array_map( 'trim', $policy );

		# The default policy is follow, so if nothing is said explicitly, we
		# do that.
		if( in_array( 'nofollow', $policy ) ) {
			$this->mFollowPolicy = 'nofollow';
		} else {
			$this->mFollowPolicy = 'follow';
		}

		if( in_array( 'noindex', $policy ) ) {
			$this->mIndexPolicy = 'noindex';
		} else {
			$this->mIndexPolicy = 'index';
		}
	}

	/**
	 * 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;
		}
	}

	public function setHTMLTitle( $name ) {$this->mHTMLtitle = $name; }
	public function setPageTitle( $name ) {
		global $action, $wgContLang;
		$name = $wgContLang->convert($name, true);
		$this->mPagetitle = $name;
		if(!empty($action)) {
			$taction =  $this->getPageTitleActionText();
			if( !empty( $taction ) ) {
				$name .= ' - '.$taction;
			}
		}

		$this->setHTMLTitle( wfMsg( 'pagetitle', $name ) );
	}
	public function getHTMLTitle() { return $this->mHTMLtitle; }
	public function getPageTitle() { return $this->mPagetitle; }
	public function setSubtitle( $str ) { $this->mSubtitle = /*$this->parse(*/$str/*)*/; } // @bug 2514
	public function appendSubtitle( $str ) { $this->mSubtitle .= /*$this->parse(*/$str/*)*/; } // @bug 2514
	public function getSubtitle() { return $this->mSubtitle; }
	public function isArticle() { return $this->mIsarticle; }
	public function setPrintable() { $this->mPrintable = true; }
	public function isPrintable() { return $this->mPrintable; }
	public function setSyndicated( $show = true ) { $this->mShowFeedLinks = $show; }
	public function isSyndicated() { return $this->mShowFeedLinks; }
	public function setFeedAppendQuery( $val ) { $this->mFeedLinksAppendQuery = $val; }
	public function getFeedAppendQuery() { return $this->mFeedLinksAppendQuery; }
	public function setOnloadHandler( $js ) { $this->mOnloadHandler = $js; }
	public function getOnloadHandler() { return $this->mOnloadHandler; }
	public function disable() { $this->mDoNothing = true; }

	public function setArticleRelated( $v ) {
		$this->mIsArticleRelated = $v;
		if ( !$v ) {
			$this->mIsarticle = false;
		}
	}
	public function setArticleFlag( $v ) {
		$this->mIsarticle = $v;
		if ( $v ) {
			$this->mIsArticleRelated = $v;
		}
	}

	public function isArticleRelated() { return $this->mIsArticleRelated; }

	public function getLanguageLinks() { return $this->mLanguageLinks; }
	public function addLanguageLinks($newLinkArray) {
		$this->mLanguageLinks += $newLinkArray;
	}
	public function setLanguageLinks($newLinkArray) {
		$this->mLanguageLinks = $newLinkArray;
	}

	public function getCategoryLinks() {
		return $this->mCategoryLinks;
	}

	/**
	 * Add an array of categories, with names in the keys
	 */
	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, 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 ) {
				$title = Title::makeTitleSafe( NS_CATEGORY, $category );
				$text = $wgContLang->convertHtml( $title->getText() );
				$this->mCategoryLinks[$type][] = $sk->makeLinkObj( $title, $text );
			}
		}
	}

	public function setCategoryLinks($categories) {
		$this->mCategoryLinks = array();
		$this->addCategoryLinks($categories);
	}

	public function suppressQuickbar() { $this->mSuppressQuickbar = true; }
	public function isQuickbarSuppressed() { return $this->mSuppressQuickbar; }

	public function disallowUserJs() { $this->mAllowUserJs = false; }
	public function isUserJsAllowed() { return $this->mAllowUserJs; }

	public function prependHTML( $text ) { $this->mBodytext = $text . $this->mBodytext; }
	public function addHTML( $text ) { $this->mBodytext .= $text; }
	public function clearHTML() { $this->mBodytext = ''; }
	public function getHTML() { return $this->mBodytext; }
	public function debug( $text ) { $this->mDebugtext .= $text; }

	/* @deprecated */
	public function setParserOptions( $options ) {
		wfDeprecated( __METHOD__ );
		return $this->parserOptions( $options );
	}

	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 mixed $revid an integer, or NULL
	 * @return mixed previous value
	 */
	public function setRevisionId( $revid ) {
		$val = is_null( $revid ) ? null : intval( $revid );
		return wfSetVar( $this->mRevisionId, $val );
	}
	
	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 string $text
	 * @param bool   $linestart
	 */
	public function addWikiText( $text, $linestart = true ) {
		global $wgTitle;
		$this->addWikiTextTitle($text, $wgTitle, $linestart);
	}

	public function addWikiTextWithTitle($text, &$title, $linestart = true) {
		$this->addWikiTextTitle($text, $title, $linestart);
	}

	function addWikiTextTitleTidy($text, &$title, $linestart = true) {
		$this->addWikiTextTitle( $text, $title, $linestart, true );
	}

	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__ );
	}

	/**
	 * @todo document
	 * @param ParserOutput object &$parserOutput
	 */
	public function addParserOutputNoText( &$parserOutput ) {
		global $wgTitle, $wgExemptFromUserRobotsControl, $wgContentNamespaces;

		$this->mLanguageLinks += $parserOutput->getLanguageLinks();
		$this->addCategoryLinks( $parserOutput->getCategories() );
		$this->mNewSectionLink = $parserOutput->getNewSection();

		if( is_null( $wgExemptFromUserRobotsControl ) ) {
			$bannedNamespaces = $wgContentNamespaces;
		} else {
			$bannedNamespaces = $wgExemptFromUserRobotsControl;
		}
		if( !in_array( $wgTitle->getNamespace(), $bannedNamespaces ) ) {
			# FIXME (bug 14900): This overrides $wgArticleRobotPolicies, and it
			# shouldn't
			$this->setIndexPolicy( $parserOutput->getIndexPolicy() );
		}

		$this->addKeywords( $parserOutput );
		$this->mParseWarnings = $parserOutput->getWarnings();
		if ( $parserOutput->getCacheTime() == -1 ) {
			$this->enableClientCache( false );
		}
		$this->mNoGallery = $parserOutput->getNoGallery();
		$this->mHeadItems = array_merge( $this->mHeadItems, (array)$parserOutput->mHeadItems );
		// 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;
			}
		}
		// Display title
		if( ( $dt = $parserOutput->getDisplayTitle() ) !== false )
			$this->setPageTitle( $dt );

		// 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 ) );
	}

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

	/**
	 * Add wikitext to the buffer, assuming that this is the primary text for a page view
	 * Saves the text into the parser cache if possible.
	 *
	 * @param string  $text
	 * @param Article $article
	 * @param bool    $cache
	 * @deprecated Use Article::outputWikitext
	 */
	public function addPrimaryWikiText( $text, $article, $cache = true ) {
		global $wgParser, $wgUser;

		wfDeprecated( __METHOD__ );

		$popts = $this->parserOptions();
		$popts->setTidy(true);
		$parserOutput = $wgParser->parse( $text, $article->mTitle,
			$popts, true, true, $this->mRevisionId );
		$popts->setTidy(false);
		if ( $cache && $article && $parserOutput->getCacheTime() != -1 ) {
			$parserCache = ParserCache::singleton();
			$parserCache->save( $parserOutput, $article, $wgUser );
		}

		$this->addParserOutput( $parserOutput );
	}

	/**
	 * @deprecated use addWikiTextTidy()
	 */
	public function addSecondaryWikiText( $text, $linestart = true ) {
		global $wgTitle;
		wfDeprecated( __METHOD__ );
		$this->addWikiTextTitleTidy($text, $wgTitle, $linestart);
	}

	/**
	 * Add wikitext with tidy enabled
	 */
	public function addWikiTextTidy(  $text, $linestart = true ) {
		global $wgTitle;
		$this->addWikiTextTitleTidy($text, $wgTitle, $linestart);
	}


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

	/**
	 * Parse wikitext and return the HTML.
	 *
	 * @param string $text
	 * @param bool   $linestart Is this the start of a line?
	 * @param bool   $interface ??
	 */
	public function parse( $text, $linestart = true, $interface = false ) {
		global $wgParser, $wgTitle;
		if( is_null( $wgTitle ) ) {
			throw new MWException( 'Empty $wgTitle in ' . __METHOD__ );
		}
		$popts = $this->parserOptions();
		if ( $interface) { $popts->setInterfaceMessage(true); }
		$parserOutput = $wgParser->parse( $text, $wgTitle, $popts,
			$linestart, true, $this->mRevisionId );
		if ( $interface) { $popts->setInterfaceMessage(false); }
		return $parserOutput->getText();
	}

	/**
	 * @param Article $article
	 * @param User    $user
	 *
	 * @return bool True if successful, else false.
	 */
	public function tryParserCache( &$article, $user ) {
		$parserCache = ParserCache::singleton();
		$parserOutput = $parserCache->get( $article, $user );
		if ( $parserOutput !== false ) {
			$this->addParserOutput( $parserOutput );
			return true;
		} else {
			return false;
		}
	}

	/**
	 * @param int $maxage 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 );
	}

	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;
	}

	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
	 */
	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 ) ) {
				wfDebug( __METHOD__.": found $cookieName\n" );
				return true;
			}
		}
		wfDebug( __METHOD__.": no cache-varying cookies found\n" );
		return false;
	}

	/** Get a complete X-Vary-Options header */
	public function getXVO() {
		$cvCookies = $this->getCacheVaryCookies();
		$xvo = 'X-Vary-Options: Accept-Encoding;list-contains=gzip,Cookie;';
		$first = true;
		foreach ( $cvCookies as $cookieName ) {
			if ( $first ) {
				$first = false;
			} else {
				$xvo .= ';';
			}
			$xvo .= 'string-contains=' . $cookieName;
		}
		return $xvo;
	}

	public function sendCacheControl() {
		global $wgUseSquid, $wgUseESI, $wgUseETag, $wgSquidMaxage, $wgRequest;

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

		# 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: Accept-Encoding, Cookie' );

		# 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' );
		}
	}

	/**
	 * 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 $wgContLanguageCode, $wgDebugRedirects, $wgMimeType;
		global $wgJsMimeType, $wgUseAjax, $wgAjaxWatch;
		global $wgEnableMWSuggest, $wgUniversalEditButton;
		global $wgArticle, $wgTitle;

		if( $this->mDoNothing ){
			return;
		}

		wfProfileIn( __METHOD__ );

		if ( '' != $this->mRedirect ) {
			# Standards require redirect URLs to be absolute
			$this->mRedirect = wfExpandUrl( $this->mRedirect );
			if( $this->mRedirectCode == '301') {
				if( !$wgDebugRedirects ) {
					$wgRequest->response()->header("HTTP/1.1 {$this->mRedirectCode} Moved Permanently");
				}
				$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 )
		{
			$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'
			);

			if ( $statusMessage[$this->mStatusCode] )
				$wgRequest->response()->header( 'HTTP/1.1 ' . $this->mStatusCode . ' ' . $statusMessage[$this->mStatusCode] );
		}

		$sk = $wgUser->getSkin();

		if ( $wgUseAjax ) {
			$this->addScriptFile( 'ajax.js' );

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

			if( $wgAjaxWatch && $wgUser->isLoggedIn() ) {
				$this->addScriptFile( 'ajaxwatch.js' );
			}
			
			if ( $wgEnableMWSuggest && !$wgUser->getOption( 'disablesuggest', false ) ){
				$this->addScriptFile( 'mwsuggest.js' );
			}
		}
		
		if( $wgUser->getBoolOption( 'editsectiononrightclick' ) ) {
			$this->addScriptFile( 'rightclickedit.js' );
		}

		if( $wgUniversalEditButton ) {
			if( isset( $wgArticle ) && isset( $wgTitle ) && $wgTitle->quickUserCan( 'edit' )
				&& ( $wgTitle->exists() || $wgTitle->quickUserCan( 'create' ) ) ) {
				// Original UniversalEditButton
				$this->addLink( array(
					'rel' => 'alternate',
					'type' => 'application/x-wiki',
					'title' => wfMsg( 'edit' ),
					'href' => $wgTitle->getFullURL( 'action=edit' )
				) );
				// Alternate edit link
				$this->addLink( array(
					'rel' => 'edit',
					'title' => wfMsg( 'edit' ),
					'href' => $wgTitle->getFullURL( 'action=edit' )
				) );
			}
		}
		
		# Buffer output; final headers may depend on later processing
		ob_start();

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

		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__ );
	}

	/**
	 * @todo document
	 * @param string $ins
	 */
	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;
	}

	/**
	 * @todo document
	 */
	public static function setEncodings() {
		global $wgInputEncoding, $wgOutputEncoding;
		global $wgUser, $wgContLang;

		$wgInputEncoding = strtolower( $wgInputEncoding );

		if ( empty( $_SERVER['HTTP_ACCEPT_CHARSET'] ) ) {
			$wgOutputEncoding = strtolower( $wgOutputEncoding );
			return;
		}
		$wgOutputEncoding = $wgInputEncoding;
	}

	/**
	 * Deprecated, use wfReportTime() instead.
	 * @return string
	 * @deprecated
	 */
	public function reportTime() {
		wfDeprecated( __METHOD__ );
		$time = wfReportTime();
		return $time;
	}

	/**
	 * Produce a "user is blocked" page.
	 *
	 * @param bool $return Whether to have a "return to $wgTitle" message or not.
	 * @return nothing
	 */
	function blockedPage( $return = true ) {
		global $wgUser, $wgContLang, $wgTitle, $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 = $wgTitle->getNamespace() > -1 ? $wgTitle : NULL;
			$this->returnToMain( null, $return );
		}
	}

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

		array_unshift( $params, 'parse' );
		array_unshift( $params, $msg );
		$this->addHTML( call_user_func_array( 'wfMsgExt', $params ) );

		$this->returnToMain();
	}

	/**
	 * Output a standard permission error page
	 *
	 * @param array $errors Error message keys
	 */
	public function showPermissionsErrorPage( $errors, $action = null )
	{
		global $wgTitle;

		$this->mDebugtext .= 'Original title: ' .
		$wgTitle->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 ) );
	}

	/** @deprecated */
	public function errorpage( $title, $msg ) {
		wfDeprecated( __METHOD__ );
		throw new ErrorPageError( $title, $msg );
	}

	/**
	 * Display an error page indicating that a given version of MediaWiki is
	 * required to use it
	 *
	 * @param mixed $version 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 string $permission key required
	 */
	public function permissionRequired( $permission ) {
		global $wgUser;

		$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',
				implode( ', ', $groups ),
				count( $groups) );
		} else {
			$this->addWikiMsg( 'badaccess-group0' );
		}
		$this->returnToMain();
	}

	/**
	 * Use permissionRequired.
	 * @deprecated
	 */
	public function sysopRequired() {
		throw new MWException( "Call to deprecated OutputPage::sysopRequired() method\n" );
	}

	/**
	 * Use permissionRequired.
	 * @deprecated
	 */
	public function developerRequired() {
		throw new MWException( "Call to deprecated OutputPage::developerRequired() method\n" );
	}

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

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

		$skin = $wgUser->getSkin();

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

		$loginTitle = SpecialPage::getTitleFor( 'Userlogin' );
		$loginLink = $skin->makeKnownLinkObj( $loginTitle, wfMsgHtml( 'loginreqlink' ), 'returnto=' . $wgTitle->getPrefixedUrl() );
		$this->addHTML( wfMsgWikiHtml( 'loginreqpagetext', $loginLink ) );
		$this->addHTML( "\n<!--" . $wgTitle->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 );
	}

	/** @deprecated */
	public function databaseError( $fname, $sql, $error, $errno ) {
		throw new MWException( "OutputPage::databaseError is obsolete\n" );
	}

	/**
	 * @param array $errors An array of arrays returned by Title::getUserPermissionsErrors
	 * @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 {
			global $wgLang;
			$action_desc = wfMsg( "action-$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">' . call_user_func_array( 'wfMsgNoTrans', reset( $errors ) ) . '</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 string $source    Source code to show (or null).
	 * @param bool   $protected Is this a permissions error?
	 * @param array  $reasons   List of reasons for this error, as returned by Title::getUserPermissionsErrors().
	 */
	public function readOnlyPage( $source = null, $protected = false, $reasons = array(), $action = null ) {
		global $wgUser, $wgTitle;
		$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->makeKnownLinkObj( $wgTitle ) ) );
			} 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">$1</div>', array( 'readonlytext', $reason ) );
		}

		// Show source, if supplied
		if( is_string( $source ) ) {
			$this->addWikiMsg( 'viewsourcetext' );
			$text = Xml::openElement( 'textarea',
						array( 'id'   => 'wpTextbox1',
						       'name' => 'wpTextbox1',
						       'cols' => $wgUser->getOption( 'cols' ),
						       'rows' => $wgUser->getOption( 'rows' ),
						       'readonly' => 'readonly' ) );
			$text .= htmlspecialchars( $source );
			$text .= Xml::closeElement( 'textarea' );
			$this->addHTML( $text );

			// Show templates used by this article
			$skin = $wgUser->getSkin();
			$article = new Article( $wgTitle );
			$this->addHTML( "<div class='templatesUsed'>
{$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( $wgTitle->exists() ) {
			$this->returnToMain( null, $wgTitle );
		}
	}

	/** @deprecated */
	public function fatalError( $message ) {
		wfDeprecated( __METHOD__ );
		throw new FatalError( $message );
	}

	/** @deprecated */
	public function unexpectedValueError( $name, $val ) {
		wfDeprecated( __METHOD__ );
		throw new FatalError( wfMsg( 'unexpected', $name, $val ) );
	}

	/** @deprecated */
	public function fileCopyError( $old, $new ) {
		wfDeprecated( __METHOD__ );
		throw new FatalError( wfMsg( 'filecopyerror', $old, $new ) );
	}

	/** @deprecated */
	public function fileRenameError( $old, $new ) {
		wfDeprecated( __METHOD__ );
		throw new FatalError( wfMsg( 'filerenameerror', $old, $new ) );
	}

	/** @deprecated */
	public function fileDeleteError( $name ) {
		wfDeprecated( __METHOD__ );
		throw new FatalError( wfMsg( 'filedeleteerror', $name ) );
	}

	/** @deprecated */
	public function fileNotFoundError( $name ) {
		wfDeprecated( __METHOD__ );
		throw new FatalError( wfMsg( 'filenotfound', $name ) );
	}

	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 Title to link
	 */
	public function addReturnTo( $title ) {
		global $wgUser;
		$this->addLink( array( 'rel' => 'next', 'href' => $title->getFullUrl() ) );
		$link = wfMsg( 'returnto', $wgUser->getSkin()->makeLinkObj( $title ) );
		$this->addHTML( "<p>{$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 null $unused No longer used
	 * @param Title $returnto Title to return to
	 */
	public function returnToMain( $unused = null, $returnto = NULL ) {
		global $wgRequest;

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

		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 );
	}

	/**
	 * This function takes the title (first item of mGoodLinks), categories, existing and broken links for the page
	 * and uses the first 10 of them for META keywords
	 *
	 * @param ParserOutput &$parserOutput
	 */
	private function addKeywords( &$parserOutput ) {
		global $wgTitle;
		$this->addKeyword( $wgTitle->getPrefixedText() );
		$count = 1;
		$links2d =& $parserOutput->getLinks();
		if ( !is_array( $links2d ) ) {
			return;
		}
		foreach ( $links2d as $dbkeys ) {
			foreach( $dbkeys as $dbkey => $unused ) {
				$this->addKeyword( $dbkey );
				if ( ++$count > 10 ) {
					break 2;
				}
			}
		}
	}

	/**
	 * @return string The doctype, opening <html>, and head element.
	 */
	public function headElement( Skin $sk ) {
		global $wgDocType, $wgDTD, $wgContLanguageCode, $wgOutputEncoding, $wgMimeType;
		global $wgXhtmlDefaultNamespace, $wgXhtmlNamespaces;
		global $wgUser, $wgContLang, $wgUseTrackbacks, $wgTitle, $wgStyleVersion;

		$this->addMeta( "http:Content-type", "$wgMimeType; charset={$wgOutputEncoding}" );
		$this->addStyle( 'common/wikiprintable.css', 'print' );
		$sk->setupUserCss( $this );

		$ret = '';

		if( $wgMimeType == 'text/xml' || $wgMimeType == 'application/xhtml+xml' || $wgMimeType == 'application/xml' ) {
			$ret .= "<?xml version=\"1.0\" encoding=\"$wgOutputEncoding\" ?>\n";
		}

		$ret .= "<!DOCTYPE html PUBLIC \"$wgDocType\"\n        \"$wgDTD\">\n";

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

		$rtl = $wgContLang->isRTL() ? " dir='RTL'" : '';
		$ret .= "<html xmlns=\"{$wgXhtmlDefaultNamespace}\" ";
		foreach($wgXhtmlNamespaces as $tag => $ns) {
			$ret .= "xmlns:{$tag}=\"{$ns}\" ";
		}
		$ret .= "xml:lang=\"$wgContLanguageCode\" lang=\"$wgContLanguageCode\" $rtl>\n";
		$ret .= "<head>\n<title>" . htmlspecialchars( $this->getHTMLTitle() ) . "</title>\n\t\t";
		$ret .= implode( "\t\t", array(
			$this->getHeadLinks(),
			$this->buildCssLinks(),
			$sk->getHeadScripts( $this->mAllowUserJs ),
			$this->mScripts,
			$this->getHeadItems(),
		));
		if( $sk->usercss ){
			$ret .= "<style type='text/css'>{$sk->usercss}</style>";
		}

		if ($wgUseTrackbacks && $this->isArticleRelated())
			$ret .= $wgTitle->trackbackRDF();

		$ret .= "</head>\n";
		return $ret;
	}
	
	protected function addDefaultMeta() {
		global $wgVersion;
		$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() {
		global $wgRequest, $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[] = Xml::element( 'meta',
				array(
					$a => $tag[0],
					'content' => $tag[1] ) );
		}
		foreach ( $this->mLinktags as $tag ) {
			$tags[] = Xml::element( 'link', $tag );
		}

		if( $wgFeed ) {
			global $wgTitle;
			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,
					$link,
					wfMsg( "page-{$format}-feed", $wgTitle->getPrefixedText() ) ); # Used messages: 'page-rss-feed' and 'page-atom-feed' (for an easier grep)
			}

			# 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, $wgFeedClasses;
			$rctitle = SpecialPage::getTitleFor( 'Recentchanges' );
			
			if ( $wgOverrideSiteFeed ) {
				foreach ( $wgOverrideSiteFeed as $type => $feedUrl ) { 
					$tags[] = $this->feedLink (
						$type,
						htmlspecialchars( $feedUrl ),
						wfMsg( "site-{$type}-feed", $wgSitename ) );
				}
			}
			else if ( $wgTitle->getPrefixedText() != $rctitle->getPrefixedText() ) {
				foreach( $wgFeedClasses as $format => $class ) {
					$tags[] = $this->feedLink(
						$format,
						$rctitle->getFullURL( "feed={$format}" ),
						wfMsg( "site-{$format}-feed", $wgSitename ) ); # For grep: 'site-rss-feed', 'site-atom-feed'.
				}
			}
		}

		return implode( "\n\t\t", $tags ) . "\n";
	}

	/**
	 * Return URLs for each supported syndication format for this page.
	 * @return array associating format keys with URLs
	 */
	public function getSyndicationLinks() {
		global $wgTitle, $wgFeedClasses;
		$links = array();

		if( $this->isSyndicated() ) {
			if( is_string( $this->getFeedAppendQuery() ) ) {
				$appendQuery = "&" . $this->getFeedAppendQuery();
			} else {
				$appendQuery = "";
			}

			foreach( $wgFeedClasses as $format => $class ) {
				$links[$format] = $wgTitle->getLocalUrl( "feed=$format{$appendQuery}" );
			}
		}
		return $links;
	}

	/**
	 * Generate a <link rel/> for an RSS feed.
	 */
	private function feedLink( $type, $url, $text ) {
		return Xml::element( 'link', array(
			'rel' => 'alternate',
			'type' => "application/$type+xml",
			'title' => $text,
			'href' => $url ) );
	}

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

	/**
	 * Build a set of <link>s for the stylesheets specified in the $this->styles array.
	 * These will be applied to various media & IE conditionals.
	 */
	public function buildCssLinks() {
		$links = array();
		foreach( $this->styles as $file => $options ) {
			$link = $this->styleLink( $file, $options );
			if( $link )
				$links[] = $link;
		}

		return implode( "\n\t\t", $links );
	}

	protected function styleLink( $style, $options ) {
		global $wgRequest;

		if( isset( $options['dir'] ) ) {
			global $wgContLang;
			$siteDir = $wgContLang->isRTL() ? 'rtl' : 'ltr';
			if( $siteDir != $options['dir'] )
				return '';
		}

		if( isset( $options['media'] ) ) {
			$media = $this->transformCssMedia( $options['media'] );
			if( is_null( $media ) ) {
				return '';
			}
		} else {
			$media = '';
		}

		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;
		}

		$attribs = array(
			'rel' => 'stylesheet',
			'href' => $url,
			'type' => 'text/css' );
		if( $media ) {
			$attribs['media'] = $media;
		}

		$link = Xml::element( 'link', $attribs );

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

	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() {
		global $wgTitle;

		$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, $wgTitle );
	}

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

	/**
	 * 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 int $lag Slave lag
	 */
	public function showLagWarning( $lag ) {
		global $wgSlaveLagWarning, $wgSlaveLagCritical;
		if( $lag >= $wgSlaveLagWarning ) {
			$message = $lag < $wgSlaveLagCritical
				? 'lag-warn-normal'
				: 'lag-warn-high';
			$warning = wfMsgExt( $message, 'parse', $lag );
			$this->addHTML( "<div class=\"mw-{$message}\">\n{$warning}\n</div>\n" );
		}
	}

	/**
	 * 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 an 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">$1</div>', 'some-error' );
	 *
	 * Is equivalent to:
	 *
	 *    $wgOut->addWikiText( '<div class="error">' . wfMsgNoTrans( 'some-error' ) . '</div>' );
	 */
	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 ) );
	}
}