Article.php

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<?php
use MediaWiki\Block\DatabaseBlock;
use MediaWiki\MediaWikiServices;
use MediaWiki\Revision\MutableRevisionRecord;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Revision\SlotRecord;

class Article implements Page {
    protected $mContext;

    protected $mPage;

    public $mParserOptions;

    public $mContentObject;

    public $mContentLoaded = false;

    public $mOldId;

    public $mRedirectedFrom = null;

    public $mRedirectUrl = false;

    public $mRevIdFetched = 0;

    private $fetchResult = null;

    public $mRevision = null;

    public $mParserOutput = null;

    protected $viewIsRenderAction = false;

    public function __construct( Title $title, $oldId = null ) {
        $this->mOldId = $oldId;
        $this->mPage = $this->newPage( $title );
    }

    protected function newPage( Title $title ) {
        return new WikiPage( $title );
    }

    public static function newFromID( $id ) {
        $t = Title::newFromID( $id );
        return $t == null ? null : new static( $t );
    }

    public static function newFromTitle( $title, IContextSource $context ) {
        if ( NS_MEDIA == $title->getNamespace() ) {
            // XXX: This should not be here, but where should it go?
            $title = Title::makeTitle( NS_FILE, $title->getDBkey() );
        }

        $page = null;
        Hooks::run( 'ArticleFromTitle', [ &$title, &$page, $context ] );
        if ( !$page ) {
            switch ( $title->getNamespace() ) {
                case NS_FILE:
                    $page = new ImagePage( $title );
                    break;
                case NS_CATEGORY:
                    $page = new CategoryPage( $title );
                    break;
                default:
                    $page = new Article( $title );
            }
        }
        $page->setContext( $context );

        return $page;
    }

    public static function newFromWikiPage( WikiPage $page, IContextSource $context ) {
        $article = self::newFromTitle( $page->getTitle(), $context );
        $article->mPage = $page; // override to keep process cached vars
        return $article;
    }

    public function getRedirectedFrom() {
        return $this->mRedirectedFrom;
    }

    public function setRedirectedFrom( Title $from ) {
        $this->mRedirectedFrom = $from;
    }

    public function getTitle() {
        return $this->mPage->getTitle();
    }

    public function getPage() {
        return $this->mPage;
    }

    public function clear() {
        $this->mContentLoaded = false;

        $this->mRedirectedFrom = null; # Title object if set
        $this->mRevIdFetched = 0;
        $this->mRedirectUrl = false;
        $this->mRevision = null;
        $this->mContentObject = null;
        $this->fetchResult = null;

        // TODO hard-deprecate direct access to public fields

        $this->mPage->clear();
    }

    protected function getContentObject() {
        if ( $this->mPage->getId() === 0 ) {
            $content = $this->getSubstituteContent();
        } else {
            $this->fetchContentObject();
            $content = $this->mContentObject;
        }

        return $content;
    }

    private function getSubstituteContent() {
        # If this is a MediaWiki:x message, then load the messages
        # and return the message value for x.
        if ( $this->getTitle()->getNamespace() == NS_MEDIAWIKI ) {
            $text = $this->getTitle()->getDefaultMessageText();
            if ( $text === false ) {
                $text = '';
            }

            $content = ContentHandler::makeContent( $text, $this->getTitle() );
        } else {
            $message = $this->getContext()->getUser()->isLoggedIn() ? 'noarticletext' : 'noarticletextanon';
            $content = new MessageContent( $message, null );
        }

        return $content;
    }

    protected function getEmptyPageParserOutput( ParserOptions $options ) {
        $content = $this->getSubstituteContent();

        return $content->getParserOutput( $this->getTitle(), 0, $options );
    }

    public function getOldID() {
        if ( is_null( $this->mOldId ) ) {
            $this->mOldId = $this->getOldIDFromRequest();
        }

        return $this->mOldId;
    }

    public function getOldIDFromRequest() {
        $this->mRedirectUrl = false;

        $request = $this->getContext()->getRequest();
        $oldid = $request->getIntOrNull( 'oldid' );

        if ( $oldid === null ) {
            return 0;
        }

        if ( $oldid !== 0 ) {
            # Load the given revision and check whether the page is another one.
            # In that case, update this instance to reflect the change.
            if ( $oldid === $this->mPage->getLatest() ) {
                $this->mRevision = $this->mPage->getRevision();
            } else {
                $this->mRevision = Revision::newFromId( $oldid );
                if ( $this->mRevision !== null ) {
                    // Revision title doesn't match the page title given?
                    if ( $this->mPage->getId() != $this->mRevision->getPage() ) {
                        $function = get_class( $this->mPage ) . '::newFromID';
                        $this->mPage = $function( $this->mRevision->getPage() );
                    }
                }
            }
        }

        $rl = MediaWikiServices::getInstance()->getRevisionLookup();
        $oldRev = $this->mRevision ? $this->mRevision->getRevisionRecord() : null;
        if ( $request->getVal( 'direction' ) == 'next' ) {
            $nextid = 0;
            if ( $oldRev ) {
                $nextRev = $rl->getNextRevision( $oldRev );
                if ( $nextRev ) {
                    $nextid = $nextRev->getId();
                }
            }
            if ( $nextid ) {
                $oldid = $nextid;
                $this->mRevision = null;
            } else {
                $this->mRedirectUrl = $this->getTitle()->getFullURL( 'redirect=no' );
            }
        } elseif ( $request->getVal( 'direction' ) == 'prev' ) {
            $previd = 0;
            if ( $oldRev ) {
                $prevRev = $rl->getPreviousRevision( $oldRev );
                if ( $prevRev ) {
                    $previd = $prevRev->getId();
                }
            }
            if ( $previd ) {
                $oldid = $previd;
                $this->mRevision = null;
            }
        }

        $this->mRevIdFetched = $this->mRevision ? $this->mRevision->getId() : 0;

        return $oldid;
    }

    protected function fetchContentObject() {
        if ( !$this->mContentLoaded ) {
            $this->fetchRevisionRecord();
        }

        return $this->mContentObject;
    }

    protected function fetchRevisionRecord() {
        if ( $this->fetchResult ) {
            return $this->mRevision ? $this->mRevision->getRevisionRecord() : null;
        }

        $this->mContentLoaded = true;
        $this->mContentObject = null;

        $oldid = $this->getOldID();

        // $this->mRevision might already be fetched by getOldIDFromRequest()
        if ( !$this->mRevision ) {
            if ( !$oldid ) {
                $this->mRevision = $this->mPage->getRevision();

                if ( !$this->mRevision ) {
                    wfDebug( __METHOD__ . " failed to find page data for title " .
                        $this->getTitle()->getPrefixedText() . "\n" );

                    // Just for sanity, output for this case is done by showMissingArticle().
                    $this->fetchResult = Status::newFatal( 'noarticletext' );
                    $this->applyContentOverride( $this->makeFetchErrorContent() );
                    return null;
                }
            } else {
                $this->mRevision = Revision::newFromId( $oldid );

                if ( !$this->mRevision ) {
                    wfDebug( __METHOD__ . " failed to load revision, rev_id $oldid\n" );

                    $this->fetchResult = Status::newFatal( 'missing-revision', $oldid );
                    $this->applyContentOverride( $this->makeFetchErrorContent() );
                    return null;
                }
            }
        }

        $this->mRevIdFetched = $this->mRevision->getId();
        $this->fetchResult = Status::newGood( $this->mRevision );

        if (
            !$this->mRevision->userCan( RevisionRecord::DELETED_TEXT, $this->getContext()->getUser() )
        ) {
            wfDebug( __METHOD__ . " failed to retrieve content of revision " .
                $this->mRevision->getId() . "\n" );

            // Just for sanity, output for this case is done by showDeletedRevisionHeader().
            $this->fetchResult = Status::newFatal( 'rev-deleted-text-permission' );
            $this->applyContentOverride( $this->makeFetchErrorContent() );
            return null;
        }

        if ( Hooks::isRegistered( 'ArticleAfterFetchContentObject' ) ) {
            $contentObject = $this->mRevision->getContent(
                RevisionRecord::FOR_THIS_USER,
                $this->getContext()->getUser()
            );

            $hookContentObject = $contentObject;

                // Avoid PHP 7.1 warning of passing $this by reference
            $articlePage = $this;

            Hooks::run(
                'ArticleAfterFetchContentObject',
                [ &$articlePage, &$hookContentObject ],
                '1.32'
            );

            if ( $hookContentObject !== $contentObject ) {
                // A hook handler is trying to override the content
                $this->applyContentOverride( $hookContentObject );
            }
        }

        // For B/C only
        $this->mContentObject = $this->mRevision->getContent(
            RevisionRecord::FOR_THIS_USER,
            $this->getContext()->getUser()
        );

        return $this->mRevision->getRevisionRecord();
    }

    private function makeFetchErrorContent() {
        if ( !$this->fetchResult || $this->fetchResult->isOK() ) {
            return null;
        }

        return new MessageContent( $this->fetchResult->getMessage() );
    }

    private function applyContentOverride( Content $override ) {
        // Construct a fake revision
        $rev = new MutableRevisionRecord( $this->getTitle() );
        $rev->setContent( SlotRecord::MAIN, $override );

        $this->mRevision = new Revision( $rev );

        // For B/C only
        $this->mContentObject = $override;
    }

    public function isCurrent() {
        # If no oldid, this is the current version.
        if ( $this->getOldID() == 0 ) {
            return true;
        }

        return $this->mPage->exists() && $this->mRevision && $this->mRevision->isCurrent();
    }

    public function getRevisionFetched() {
        $this->fetchRevisionRecord();

        if ( $this->fetchResult->isOK() ) {
            return $this->mRevision;
        }
    }

    public function getRevIdFetched() {
        if ( $this->fetchResult && $this->fetchResult->isOK() ) {
            return $this->fetchResult->value->getId();
        } else {
            return $this->mPage->getLatest();
        }
    }

    public function view() {
        global $wgUseFileCache;

        # Get variables from query string
        # As side effect this will load the revision and update the title
        # in a revision ID is passed in the request, so this should remain
        # the first call of this method even if $oldid is used way below.
        $oldid = $this->getOldID();

        $user = $this->getContext()->getUser();
        # Another whitelist check in case getOldID() is altering the title
        $permErrors = $this->getTitle()->getUserPermissionsErrors( 'read', $user );
        if ( count( $permErrors ) ) {
            wfDebug( __METHOD__ . ": denied on secondary read check\n" );
            throw new PermissionsError( 'read', $permErrors );
        }

        $outputPage = $this->getContext()->getOutput();
        # getOldID() may as well want us to redirect somewhere else
        if ( $this->mRedirectUrl ) {
            $outputPage->redirect( $this->mRedirectUrl );
            wfDebug( __METHOD__ . ": redirecting due to oldid\n" );

            return;
        }

        # If we got diff in the query, we want to see a diff page instead of the article.
        if ( $this->getContext()->getRequest()->getCheck( 'diff' ) ) {
            wfDebug( __METHOD__ . ": showing diff page\n" );
            $this->showDiffPage();

            return;
        }

        # Set page title (may be overridden by DISPLAYTITLE)
        $outputPage->setPageTitle( $this->getTitle()->getPrefixedText() );

        $outputPage->setArticleFlag( true );
        # Allow frames by default
        $outputPage->allowClickjacking();

        $parserCache = MediaWikiServices::getInstance()->getParserCache();

        $parserOptions = $this->getParserOptions();
        $poOptions = [];
        # Render printable version, use printable version cache
        if ( $outputPage->isPrintable() ) {
            $parserOptions->setIsPrintable( true );
            $poOptions['enableSectionEditLinks'] = false;
        } elseif ( $this->viewIsRenderAction || !$this->isCurrent() ||
            !MediaWikiServices::getInstance()->getPermissionManager()
                ->quickUserCan( 'edit', $user, $this->getTitle() )
        ) {
            $poOptions['enableSectionEditLinks'] = false;
        }

        # Try client and file cache
        if ( $oldid === 0 && $this->mPage->checkTouched() ) {
            # Try to stream the output from file cache
            if ( $wgUseFileCache && $this->tryFileCache() ) {
                wfDebug( __METHOD__ . ": done file cache\n" );
                # tell wgOut that output is taken care of
                $outputPage->disable();
                $this->mPage->doViewUpdates( $user, $oldid );

                return;
            }
        }

        # Should the parser cache be used?
        $useParserCache = $this->mPage->shouldCheckParserCache( $parserOptions, $oldid );
        wfDebug( 'Article::view using parser cache: ' . ( $useParserCache ? 'yes' : 'no' ) . "\n" );
        if ( $user->getStubThreshold() ) {
            MediaWikiServices::getInstance()->getStatsdDataFactory()->increment( 'pcache_miss_stub' );
        }

        $this->showRedirectedFromHeader();
        $this->showNamespaceHeader();

        # Iterate through the possible ways of constructing the output text.
        # Keep going until $outputDone is set, or we run out of things to do.
        $pass = 0;
        $outputDone = false;
        $this->mParserOutput = false;

        while ( !$outputDone && ++$pass ) {
            switch ( $pass ) {
                case 1:
                    // Avoid PHP 7.1 warning of passing $this by reference
                    $articlePage = $this;
                    Hooks::run( 'ArticleViewHeader', [ &$articlePage, &$outputDone, &$useParserCache ] );
                    break;
                case 2:
                    # Early abort if the page doesn't exist
                    if ( !$this->mPage->exists() ) {
                        wfDebug( __METHOD__ . ": showing missing article\n" );
                        $this->showMissingArticle();
                        $this->mPage->doViewUpdates( $user );
                        return;
                    }

                    # Try the parser cache
                    if ( $useParserCache ) {
                        $this->mParserOutput = $parserCache->get( $this->mPage, $parserOptions );

                        if ( $this->mParserOutput !== false ) {
                            if ( $oldid ) {
                                wfDebug( __METHOD__ . ": showing parser cache contents for current rev permalink\n" );
                                $this->setOldSubtitle( $oldid );
                            } else {
                                wfDebug( __METHOD__ . ": showing parser cache contents\n" );
                            }
                            $outputPage->addParserOutput( $this->mParserOutput, $poOptions );
                            # Ensure that UI elements requiring revision ID have
                            # the correct version information.
                            $outputPage->setRevisionId( $this->mPage->getLatest() );
                            # Preload timestamp to avoid a DB hit
                            $cachedTimestamp = $this->mParserOutput->getTimestamp();
                            if ( $cachedTimestamp !== null ) {
                                $outputPage->setRevisionTimestamp( $cachedTimestamp );
                                $this->mPage->setTimestamp( $cachedTimestamp );
                            }
                            $outputDone = true;
                        }
                    }
                    break;
                case 3:
                    # Are we looking at an old revision
                    $rev = $this->fetchRevisionRecord();
                    if ( $oldid && $this->fetchResult->isOK() ) {
                        $this->setOldSubtitle( $oldid );

                        if ( !$this->showDeletedRevisionHeader() ) {
                            wfDebug( __METHOD__ . ": cannot view deleted revision\n" );
                            return;
                        }
                    }

                    # Ensure that UI elements requiring revision ID have
                    # the correct version information.
                    $outputPage->setRevisionId( $this->getRevIdFetched() );
                    # Preload timestamp to avoid a DB hit
                    $outputPage->setRevisionTimestamp( $this->mPage->getTimestamp() );

                    # Pages containing custom CSS or JavaScript get special treatment
                    if ( $this->getTitle()->isSiteConfigPage() || $this->getTitle()->isUserConfigPage() ) {
                        $dir = $this->getContext()->getLanguage()->getDir();
                        $lang = $this->getContext()->getLanguage()->getHtmlCode();

                        $outputPage->wrapWikiMsg(
                            "<div id='mw-clearyourcache' lang='$lang' dir='$dir' class='mw-content-$dir'>\n$1\n</div>",
                            'clearyourcache'
                        );
                    } elseif ( !Hooks::run( 'ArticleRevisionViewCustom', [
                            $rev,
                            $this->getTitle(),
                            $oldid,
                            $outputPage,
                        ] )
                    ) {
                        // NOTE: sync with hooks called in DifferenceEngine::renderNewRevision()
                        // Allow extensions do their own custom view for certain pages
                        $outputDone = true;
                    } elseif ( !Hooks::run( 'ArticleContentViewCustom',
                        [ $this->fetchContentObject(), $this->getTitle(), $outputPage ], '1.32' )
                    ) {
                        // NOTE: sync with hooks called in DifferenceEngine::renderNewRevision()
                        // Allow extensions do their own custom view for certain pages
                        $outputDone = true;
                    }
                    break;
                case 4:
                    # Run the parse, protected by a pool counter
                    wfDebug( __METHOD__ . ": doing uncached parse\n" );

                    $rev = $this->fetchRevisionRecord();
                    $error = null;

                    if ( $rev ) {
                        $poolArticleView = new PoolWorkArticleView(
                            $this->getPage(),
                            $parserOptions,
                            $this->getRevIdFetched(),
                            $useParserCache,
                            $rev,
                            // permission checking was done earlier via showDeletedRevisionHeader()
                            RevisionRecord::RAW
                        );
                        $ok = $poolArticleView->execute();
                        $error = $poolArticleView->getError();
                        $this->mParserOutput = $poolArticleView->getParserOutput() ?: null;

                        # Don't cache a dirty ParserOutput object
                        if ( $poolArticleView->getIsDirty() ) {
                            $outputPage->setCdnMaxage( 0 );
                            $outputPage->addHTML( "<!-- parser cache is expired, " .
                                "sending anyway due to pool overload-->\n" );
                        }
                    } else {
                        $ok = false;
                    }

                    if ( !$ok ) {
                        if ( $error ) {
                            $outputPage->clearHTML(); // for release() errors
                            $outputPage->enableClientCache( false );
                            $outputPage->setRobotPolicy( 'noindex,nofollow' );

                            $errortext = $error->getWikiText(
                                false, 'view-pool-error', $this->getContext()->getLanguage()
                            );
                            $outputPage->wrapWikiTextAsInterface( 'errorbox', $errortext );
                        }
                        # Connection or timeout error
                        return;
                    }

                    if ( $this->mParserOutput ) {
                        $outputPage->addParserOutput( $this->mParserOutput, $poOptions );
                    }

                    if ( $rev && $this->getRevisionRedirectTarget( $rev ) ) {
                        $outputPage->addSubtitle( "<span id=\"redirectsub\">" .
                            $this->getContext()->msg( 'redirectpagesub' )->parse() . "</span>" );
                    }

                    $outputDone = true;
                    break;
                # Should be unreachable, but just in case...
                default:
                    break 2;
            }
        }

        // Get the ParserOutput actually *displayed* here.
        // Note that $this->mParserOutput is the *current*/oldid version output.
        // Note that the ArticleViewHeader hook is allowed to set $outputDone to a
        // ParserOutput instance.
        $pOutput = ( $outputDone instanceof ParserOutput )
            ? $outputDone // object fetched by hook
            : ( $this->mParserOutput ?: null ); // ParserOutput or null, avoid false

        # Adjust title for main page & pages with displaytitle
        if ( $pOutput ) {
            $this->adjustDisplayTitle( $pOutput );
        }

        # For the main page, overwrite the <title> element with the con-
        # tents of 'pagetitle-view-mainpage' instead of the default (if
        # that's not empty).
        # This message always exists because it is in the i18n files
        if ( $this->getTitle()->isMainPage() ) {
            $msg = wfMessage( 'pagetitle-view-mainpage' )->inContentLanguage();
            if ( !$msg->isDisabled() ) {
                $outputPage->setHTMLTitle( $msg->title( $this->getTitle() )->text() );
            }
        }

        # Use adaptive TTLs for CDN so delayed/failed purges are noticed less often.
        # This could use getTouched(), but that could be scary for major template edits.
        $outputPage->adaptCdnTTL( $this->mPage->getTimestamp(), IExpiringStore::TTL_DAY );

        # Check for any __NOINDEX__ tags on the page using $pOutput
        $policy = $this->getRobotPolicy( 'view', $pOutput ?: null );
        $outputPage->setIndexPolicy( $policy['index'] );
        $outputPage->setFollowPolicy( $policy['follow'] ); // FIXME: test this

        $this->showViewFooter();
        $this->mPage->doViewUpdates( $user, $oldid ); // FIXME: test this

        # Load the postEdit module if the user just saved this revision
        # See also EditPage::setPostEditCookie
        $request = $this->getContext()->getRequest();
        $cookieKey = EditPage::POST_EDIT_COOKIE_KEY_PREFIX . $this->getRevIdFetched();
        $postEdit = $request->getCookie( $cookieKey );
        if ( $postEdit ) {
            # Clear the cookie. This also prevents caching of the response.
            $request->response()->clearCookie( $cookieKey );
            $outputPage->addJsConfigVars( 'wgPostEdit', $postEdit );
            $outputPage->addModules( 'mediawiki.action.view.postEdit' ); // FIXME: test this
        }
    }

    private function getRevisionRedirectTarget( RevisionRecord $revision ) {
        // TODO: find a *good* place for the code that determines the redirect target for
        // a given revision!
        // NOTE: Use main slot content. Compare code in DerivedPageDataUpdater::revisionIsRedirect.
        $content = $revision->getContent( SlotRecord::MAIN );
        return $content ? $content->getRedirectTarget() : null;
    }

    public function adjustDisplayTitle( ParserOutput $pOutput ) {
        $out = $this->getContext()->getOutput();

        # Adjust the title if it was set by displaytitle, -{T|}- or language conversion
        $titleText = $pOutput->getTitleText();
        if ( strval( $titleText ) !== '' ) {
            $out->setPageTitle( $titleText );
            $out->setDisplayTitle( $titleText );
        }
    }

    protected function showDiffPage() {
        $request = $this->getContext()->getRequest();
        $user = $this->getContext()->getUser();
        $diff = $request->getVal( 'diff' );
        $rcid = $request->getVal( 'rcid' );
        $diffOnly = $request->getBool( 'diffonly', $user->getOption( 'diffonly' ) );
        $purge = $request->getVal( 'action' ) == 'purge';
        $unhide = $request->getInt( 'unhide' ) == 1;
        $oldid = $this->getOldID();

        $rev = $this->getRevisionFetched();

        if ( !$rev ) {
            $this->getContext()->getOutput()->setPageTitle( wfMessage( 'errorpagetitle' ) );
            $msg = $this->getContext()->msg( 'difference-missing-revision' )
                ->params( $oldid )
                ->numParams( 1 )
                ->parseAsBlock();
            $this->getContext()->getOutput()->addHTML( $msg );
            return;
        }

        $contentHandler = $rev->getContentHandler();
        $de = $contentHandler->createDifferenceEngine(
            $this->getContext(),
            $oldid,
            $diff,
            $rcid,
            $purge,
            $unhide
        );

        // DifferenceEngine directly fetched the revision:
        $this->mRevIdFetched = $de->getNewid();
        $de->showDiffPage( $diffOnly );

        // Run view updates for the newer revision being diffed (and shown
        // below the diff if not $diffOnly).
        list( $old, $new ) = $de->mapDiffPrevNext( $oldid, $diff );
        // New can be false, convert it to 0 - this conveniently means the latest revision
        $this->mPage->doViewUpdates( $user, (int)$new );
    }

    public function getRobotPolicy( $action, ParserOutput $pOutput = null ) {
        global $wgArticleRobotPolicies, $wgNamespaceRobotPolicies, $wgDefaultRobotPolicy;

        $ns = $this->getTitle()->getNamespace();

        # Don't index user and user talk pages for blocked users (T13443)
        if ( ( $ns == NS_USER || $ns == NS_USER_TALK ) && !$this->getTitle()->isSubpage() ) {
            $specificTarget = null;
            $vagueTarget = null;
            $titleText = $this->getTitle()->getText();
            if ( IP::isValid( $titleText ) ) {
                $vagueTarget = $titleText;
            } else {
                $specificTarget = $titleText;
            }
            if ( DatabaseBlock::newFromTarget( $specificTarget, $vagueTarget ) instanceof DatabaseBlock ) {
                return [
                    'index' => 'noindex',
                    'follow' => 'nofollow'
                ];
            }
        }

        if ( $this->mPage->getId() === 0 || $this->getOldID() ) {
            # Non-articles (special pages etc), and old revisions
            return [
                'index' => 'noindex',
                'follow' => 'nofollow'
            ];
        } elseif ( $this->getContext()->getOutput()->isPrintable() ) {
            # Discourage indexing of printable versions, but encourage following
            return [
                'index' => 'noindex',
                'follow' => 'follow'
            ];
        } elseif ( $this->getContext()->getRequest()->getInt( 'curid' ) ) {
            # For ?curid=x urls, disallow indexing
            return [
                'index' => 'noindex',
                'follow' => 'follow'
            ];
        }

        # Otherwise, construct the policy based on the various config variables.
        $policy = self::formatRobotPolicy( $wgDefaultRobotPolicy );

        if ( isset( $wgNamespaceRobotPolicies[$ns] ) ) {
            # Honour customised robot policies for this namespace
            $policy = array_merge(
                $policy,
                self::formatRobotPolicy( $wgNamespaceRobotPolicies[$ns] )
            );
        }
        if ( $this->getTitle()->canUseNoindex() && is_object( $pOutput ) && $pOutput->getIndexPolicy() ) {
            # __INDEX__ and __NOINDEX__ magic words, if allowed. Incorporates
            # a final sanity check that we have really got the parser output.
            $policy = array_merge(
                $policy,
                [ 'index' => $pOutput->getIndexPolicy() ]
            );
        }

        if ( isset( $wgArticleRobotPolicies[$this->getTitle()->getPrefixedText()] ) ) {
            # (T16900) site config can override user-defined __INDEX__ or __NOINDEX__
            $policy = array_merge(
                $policy,
                self::formatRobotPolicy( $wgArticleRobotPolicies[$this->getTitle()->getPrefixedText()] )
            );
        }

        return $policy;
    }

    public static function formatRobotPolicy( $policy ) {
        if ( is_array( $policy ) ) {
            return $policy;
        } elseif ( !$policy ) {
            return [];
        }

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

        $arr = [];
        foreach ( $policy as $var ) {
            if ( in_array( $var, [ 'index', 'noindex' ] ) ) {
                $arr['index'] = $var;
            } elseif ( in_array( $var, [ 'follow', 'nofollow' ] ) ) {
                $arr['follow'] = $var;
            }
        }

        return $arr;
    }

    public function showRedirectedFromHeader() {
        global $wgRedirectSources;

        $context = $this->getContext();
        $outputPage = $context->getOutput();
        $request = $context->getRequest();
        $rdfrom = $request->getVal( 'rdfrom' );

        // Construct a URL for the current page view, but with the target title
        $query = $request->getValues();
        unset( $query['rdfrom'] );
        unset( $query['title'] );
        if ( $this->getTitle()->isRedirect() ) {
            // Prevent double redirects
            $query['redirect'] = 'no';
        }
        $redirectTargetUrl = $this->getTitle()->getLinkURL( $query );

        if ( isset( $this->mRedirectedFrom ) ) {
            // Avoid PHP 7.1 warning of passing $this by reference
            $articlePage = $this;

            // This is an internally redirected page view.
            // We'll need a backlink to the source page for navigation.
            if ( Hooks::run( 'ArticleViewRedirect', [ &$articlePage ] ) ) {
                $redir = Linker::linkKnown(
                    $this->mRedirectedFrom,
                    null,
                    [],
                    [ 'redirect' => 'no' ]
                );

                $outputPage->addSubtitle( "<span class=\"mw-redirectedfrom\">" .
                    $context->msg( 'redirectedfrom' )->rawParams( $redir )->parse()
                . "</span>" );

                // Add the script to update the displayed URL and
                // set the fragment if one was specified in the redirect
                $outputPage->addJsConfigVars( [
                    'wgInternalRedirectTargetUrl' => $redirectTargetUrl,
                ] );
                $outputPage->addModules( 'mediawiki.action.view.redirect' );

                // Add a <link rel="canonical"> tag
                $outputPage->setCanonicalUrl( $this->getTitle()->getCanonicalURL() );

                // Tell the output object that the user arrived at this article through a redirect
                $outputPage->setRedirectedFrom( $this->mRedirectedFrom );

                return true;
            }
        } elseif ( $rdfrom ) {
            // This is an externally redirected view, from some other wiki.
            // If it was reported from a trusted site, supply a backlink.
            if ( $wgRedirectSources && preg_match( $wgRedirectSources, $rdfrom ) ) {
                $redir = Linker::makeExternalLink( $rdfrom, $rdfrom );
                $outputPage->addSubtitle( "<span class=\"mw-redirectedfrom\">" .
                    $context->msg( 'redirectedfrom' )->rawParams( $redir )->parse()
                . "</span>" );

                // Add the script to update the displayed URL
                $outputPage->addJsConfigVars( [
                    'wgInternalRedirectTargetUrl' => $redirectTargetUrl,
                ] );
                $outputPage->addModules( 'mediawiki.action.view.redirect' );

                return true;
            }
        }

        return false;
    }

    public function showNamespaceHeader() {
        if ( $this->getTitle()->isTalkPage() && !wfMessage( 'talkpageheader' )->isDisabled() ) {
            $this->getContext()->getOutput()->wrapWikiMsg(
                "<div class=\"mw-talkpageheader\">\n$1\n</div>",
                [ 'talkpageheader' ]
            );
        }
    }

    public function showViewFooter() {
        # check if we're displaying a [[User talk:x.x.x.x]] anonymous talk page
        if ( $this->getTitle()->getNamespace() == NS_USER_TALK
            && IP::isValid( $this->getTitle()->getText() )
        ) {
            $this->getContext()->getOutput()->addWikiMsg( 'anontalkpagetext' );
        }

        // Show a footer allowing the user to patrol the shown revision or page if possible
        $patrolFooterShown = $this->showPatrolFooter();

        Hooks::run( 'ArticleViewFooter', [ $this, $patrolFooterShown ] );
    }

    public function showPatrolFooter() {
        global $wgUseNPPatrol, $wgUseRCPatrol, $wgUseFilePatrol;

        // Allow hooks to decide whether to not output this at all
        if ( !Hooks::run( 'ArticleShowPatrolFooter', [ $this ] ) ) {
            return false;
        }

        $outputPage = $this->getContext()->getOutput();
        $user = $this->getContext()->getUser();
        $title = $this->getTitle();
        $rc = false;

        if ( !MediaWikiServices::getInstance()->getPermissionManager()
                ->quickUserCan( 'patrol', $user, $title )
            || !( $wgUseRCPatrol || $wgUseNPPatrol
                || ( $wgUseFilePatrol && $title->inNamespace( NS_FILE ) ) )
        ) {
            // Patrolling is disabled or the user isn't allowed to
            return false;
        }

        if ( $this->mRevision
            && !RecentChange::isInRCLifespan( $this->mRevision->getTimestamp(), 21600 )
        ) {
            // The current revision is already older than what could be in the RC table
            // 6h tolerance because the RC might not be cleaned out regularly
            return false;
        }

        // Check for cached results
        $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
        $key = $cache->makeKey( 'unpatrollable-page', $title->getArticleID() );
        if ( $cache->get( $key ) ) {
            return false;
        }

        $dbr = wfGetDB( DB_REPLICA );
        $oldestRevisionTimestamp = $dbr->selectField(
            'revision',
            'MIN( rev_timestamp )',
            [ 'rev_page' => $title->getArticleID() ],
            __METHOD__
        );

        // New page patrol: Get the timestamp of the oldest revison which
        // the revision table holds for the given page. Then we look
        // whether it's within the RC lifespan and if it is, we try
        // to get the recentchanges row belonging to that entry
        // (with rc_new = 1).
        $recentPageCreation = false;
        if ( $oldestRevisionTimestamp
            && RecentChange::isInRCLifespan( $oldestRevisionTimestamp, 21600 )
        ) {
            // 6h tolerance because the RC might not be cleaned out regularly
            $recentPageCreation = true;
            $rc = RecentChange::newFromConds(
                [
                    'rc_new' => 1,
                    'rc_timestamp' => $oldestRevisionTimestamp,
                    'rc_namespace' => $title->getNamespace(),
                    'rc_cur_id' => $title->getArticleID()
                ],
                __METHOD__
            );
            if ( $rc ) {
                // Use generic patrol message for new pages
                $markPatrolledMsg = wfMessage( 'markaspatrolledtext' );
            }
        }

        // File patrol: Get the timestamp of the latest upload for this page,
        // check whether it is within the RC lifespan and if it is, we try
        // to get the recentchanges row belonging to that entry
        // (with rc_type = RC_LOG, rc_log_type = upload).
        $recentFileUpload = false;
        if ( ( !$rc || $rc->getAttribute( 'rc_patrolled' ) ) && $wgUseFilePatrol
            && $title->getNamespace() === NS_FILE ) {
            // Retrieve timestamp of most recent upload
            $newestUploadTimestamp = $dbr->selectField(
                'image',
                'MAX( img_timestamp )',
                [ 'img_name' => $title->getDBkey() ],
                __METHOD__
            );
            if ( $newestUploadTimestamp
                && RecentChange::isInRCLifespan( $newestUploadTimestamp, 21600 )
            ) {
                // 6h tolerance because the RC might not be cleaned out regularly
                $recentFileUpload = true;
                $rc = RecentChange::newFromConds(
                    [
                        'rc_type' => RC_LOG,
                        'rc_log_type' => 'upload',
                        'rc_timestamp' => $newestUploadTimestamp,
                        'rc_namespace' => NS_FILE,
                        'rc_cur_id' => $title->getArticleID()
                    ],
                    __METHOD__
                );
                if ( $rc ) {
                    // Use patrol message specific to files
                    $markPatrolledMsg = wfMessage( 'markaspatrolledtext-file' );
                }
            }
        }

        if ( !$recentPageCreation && !$recentFileUpload ) {
            // Page creation and latest upload (for files) is too old to be in RC

            // We definitely can't patrol so cache the information
            // When a new file version is uploaded, the cache is cleared
            $cache->set( $key, '1' );

            return false;
        }

        if ( !$rc ) {
            // Don't cache: This can be hit if the page gets accessed very fast after
            // its creation / latest upload or in case we have high replica DB lag. In case
            // the revision is too old, we will already return above.
            return false;
        }

        if ( $rc->getAttribute( 'rc_patrolled' ) ) {
            // Patrolled RC entry around

            // Cache the information we gathered above in case we can't patrol
            // Don't cache in case we can patrol as this could change
            $cache->set( $key, '1' );

            return false;
        }

        if ( $rc->getPerformer()->equals( $user ) ) {
            // Don't show a patrol link for own creations/uploads. If the user could
            // patrol them, they already would be patrolled
            return false;
        }

        $outputPage->preventClickjacking();
        if ( MediaWikiServices::getInstance()
                ->getPermissionManager()
                ->userHasRight( $user, 'writeapi' )
        ) {
            $outputPage->addModules( 'mediawiki.page.patrol.ajax' );
        }

        $link = Linker::linkKnown(
            $title,
            $markPatrolledMsg->escaped(),
            [],
            [
                'action' => 'markpatrolled',
                'rcid' => $rc->getAttribute( 'rc_id' ),
            ]
        );

        $outputPage->addHTML(
            "<div class='patrollink' data-mw='interface'>" .
                wfMessage( 'markaspatrolledlink' )->rawParams( $link )->escaped() .
            '</div>'
        );

        return true;
    }

    public static function purgePatrolFooterCache( $articleID ) {
        $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
        $cache->delete( $cache->makeKey( 'unpatrollable-page', $articleID ) );
    }

    public function showMissingArticle() {
        global $wgSend404Code;

        $outputPage = $this->getContext()->getOutput();
        // Whether the page is a root user page of an existing user (but not a subpage)
        $validUserPage = false;

        $title = $this->getTitle();

        $services = MediaWikiServices::getInstance();

        # Show info in user (talk) namespace. Does the user exist? Is he blocked?
        if ( $title->getNamespace() == NS_USER
            || $title->getNamespace() == NS_USER_TALK
        ) {
            $rootPart = explode( '/', $title->getText() )[0];
            $user = User::newFromName( $rootPart, false /* allow IP users */ );
            $ip = User::isIP( $rootPart );
            $block = DatabaseBlock::newFromTarget( $user, $user );

            if ( !( $user && $user->isLoggedIn() ) && !$ip ) { # User does not exist
                $outputPage->wrapWikiMsg( "<div class=\"mw-userpage-userdoesnotexist error\">\n\$1\n</div>",
                    [ 'userpage-userdoesnotexist-view', wfEscapeWikiText( $rootPart ) ] );
            } elseif (
                !is_null( $block ) &&
                $block->getType() != DatabaseBlock::TYPE_AUTO &&
                ( $block->isSitewide() || $user->isBlockedFrom( $title ) )
            ) {
                // Show log extract if the user is sitewide blocked or is partially
                // blocked and not allowed to edit their user page or user talk page
                LogEventsList::showLogExtract(
                    $outputPage,
                    'block',
                    $services->getNamespaceInfo()->getCanonicalName( NS_USER ) . ':' .
                        $block->getTarget(),
                    '',
                    [
                        'lim' => 1,
                        'showIfEmpty' => false,
                        'msgKey' => [
                            'blocked-notice-logextract',
                            $user->getName() # Support GENDER in notice
                        ]
                    ]
                );
                $validUserPage = !$title->isSubpage();
            } else {
                $validUserPage = !$title->isSubpage();
            }
        }

        Hooks::run( 'ShowMissingArticle', [ $this ] );

        # Show delete and move logs if there were any such events.
        # The logging query can DOS the site when bots/crawlers cause 404 floods,
        # so be careful showing this. 404 pages must be cheap as they are hard to cache.
        $dbCache = ObjectCache::getInstance( 'db-replicated' );
        $key = $dbCache->makeKey( 'page-recent-delete', md5( $title->getPrefixedText() ) );
        $loggedIn = $this->getContext()->getUser()->isLoggedIn();
        $sessionExists = $this->getContext()->getRequest()->getSession()->isPersistent();
        if ( $loggedIn || $dbCache->get( $key ) || $sessionExists ) {
            $logTypes = [ 'delete', 'move', 'protect' ];

            $dbr = wfGetDB( DB_REPLICA );

            $conds = [ 'log_action != ' . $dbr->addQuotes( 'revision' ) ];
            // Give extensions a chance to hide their (unrelated) log entries
            Hooks::run( 'Article::MissingArticleConditions', [ &$conds, $logTypes ] );
            LogEventsList::showLogExtract(
                $outputPage,
                $logTypes,
                $title,
                '',
                [
                    'lim' => 10,
                    'conds' => $conds,
                    'showIfEmpty' => false,
                    'msgKey' => [ $loggedIn || $sessionExists
                        ? 'moveddeleted-notice'
                        : 'moveddeleted-notice-recent'
                    ]
                ]
            );
        }

        if ( !$this->mPage->hasViewableContent() && $wgSend404Code && !$validUserPage ) {
            // If there's no backing content, send a 404 Not Found
            // for better machine handling of broken links.
            $this->getContext()->getRequest()->response()->statusHeader( 404 );
        }

        // Also apply the robot policy for nonexisting pages (even if a 404 was used for sanity)
        $policy = $this->getRobotPolicy( 'view' );
        $outputPage->setIndexPolicy( $policy['index'] );
        $outputPage->setFollowPolicy( $policy['follow'] );

        $hookResult = Hooks::run( 'BeforeDisplayNoArticleText', [ $this ] );

        if ( !$hookResult ) {
            return;
        }

        # Show error message
        $oldid = $this->getOldID();
        $pm = MediaWikiServices::getInstance()->getPermissionManager();
        if ( !$oldid && $title->getNamespace() === NS_MEDIAWIKI && $title->hasSourceText() ) {
            // use fake Content object for system message
            $parserOptions = ParserOptions::newCanonical( 'canonical' );
            $outputPage->addParserOutput( $this->getEmptyPageParserOutput( $parserOptions ) );
        } else {
            if ( $oldid ) {
                $text = wfMessage( 'missing-revision', $oldid )->plain();
            } elseif ( $pm->quickUserCan( 'create', $this->getContext()->getUser(), $title ) &&
                $pm->quickUserCan( 'edit', $this->getContext()->getUser(), $title )
            ) {
                $message = $this->getContext()->getUser()->isLoggedIn() ? 'noarticletext' : 'noarticletextanon';
                $text = wfMessage( $message )->plain();
            } else {
                $text = wfMessage( 'noarticletext-nopermission' )->plain();
            }

            $dir = $this->getContext()->getLanguage()->getDir();
            $lang = $this->getContext()->getLanguage()->getHtmlCode();
            $outputPage->addWikiTextAsInterface( Xml::openElement( 'div', [
                'class' => "noarticletext mw-content-$dir",
                'dir' => $dir,
                'lang' => $lang,
            ] ) . "\n$text\n</div>" );
        }
    }

    public function showDeletedRevisionHeader() {
        if ( !$this->mRevision->isDeleted( RevisionRecord::DELETED_TEXT ) ) {
            // Not deleted
            return true;
        }

        $outputPage = $this->getContext()->getOutput();
        $user = $this->getContext()->getUser();
        // If the user is not allowed to see it...
        if ( !$this->mRevision->userCan( RevisionRecord::DELETED_TEXT, $user ) ) {
            $outputPage->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n",
                'rev-deleted-text-permission' );

            return false;
        // If the user needs to confirm that they want to see it...
        } elseif ( $this->getContext()->getRequest()->getInt( 'unhide' ) != 1 ) {
            # Give explanation and add a link to view the revision...
            $oldid = intval( $this->getOldID() );
            $link = $this->getTitle()->getFullURL( "oldid={$oldid}&unhide=1" );
            $msg = $this->mRevision->isDeleted( RevisionRecord::DELETED_RESTRICTED ) ?
                'rev-suppressed-text-unhide' : 'rev-deleted-text-unhide';
            $outputPage->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n",
                [ $msg, $link ] );

            return false;
        // We are allowed to see...
        } else {
            $msg = $this->mRevision->isDeleted( RevisionRecord::DELETED_RESTRICTED ) ?
                'rev-suppressed-text-view' : 'rev-deleted-text-view';
            $outputPage->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n", $msg );

            return true;
        }
    }

    public function setOldSubtitle( $oldid = 0 ) {
        // Avoid PHP 7.1 warning of passing $this by reference
        $articlePage = $this;

        if ( !Hooks::run( 'DisplayOldSubtitle', [ &$articlePage, &$oldid ] ) ) {
            return;
        }

        $context = $this->getContext();
        $unhide = $context->getRequest()->getInt( 'unhide' ) == 1;

        # Cascade unhide param in links for easy deletion browsing
        $extraParams = [];
        if ( $unhide ) {
            $extraParams['unhide'] = 1;
        }

        if ( $this->mRevision && $this->mRevision->getId() === $oldid ) {
            $revision = $this->mRevision;
        } else {
            $revision = Revision::newFromId( $oldid );
        }

        $timestamp = $revision->getTimestamp();

        $current = ( $oldid == $this->mPage->getLatest() );
        $language = $context->getLanguage();
        $user = $context->getUser();

        $td = $language->userTimeAndDate( $timestamp, $user );
        $tddate = $language->userDate( $timestamp, $user );
        $tdtime = $language->userTime( $timestamp, $user );

        # Show user links if allowed to see them. If hidden, then show them only if requested...
        $userlinks = Linker::revUserTools( $revision, !$unhide );

        $infomsg = $current && !$context->msg( 'revision-info-current' )->isDisabled()
            ? 'revision-info-current'
            : 'revision-info';

        $outputPage = $context->getOutput();
        $revisionInfo = "<div id=\"mw-{$infomsg}\">" .
            $context->msg( $infomsg, $td )
                ->rawParams( $userlinks )
                ->params( $revision->getId(), $tddate, $tdtime, $revision->getUserText() )
                ->rawParams( Linker::revComment( $revision, true, true ) )
                ->parse() .
            "</div>";

        $lnk = $current
            ? $context->msg( 'currentrevisionlink' )->escaped()
            : Linker::linkKnown(
                $this->getTitle(),
                $context->msg( 'currentrevisionlink' )->escaped(),
                [],
                $extraParams
            );
        $curdiff = $current
            ? $context->msg( 'diff' )->escaped()
            : Linker::linkKnown(
                $this->getTitle(),
                $context->msg( 'diff' )->escaped(),
                [],
                [
                    'diff' => 'cur',
                    'oldid' => $oldid
                ] + $extraParams
            );
        $rl = MediaWikiServices::getInstance()->getRevisionLookup();
        $prevExist = (bool)$rl->getPreviousRevision( $revision->getRevisionRecord() );
        $prevlink = $prevExist
            ? Linker::linkKnown(
                $this->getTitle(),
                $context->msg( 'previousrevision' )->escaped(),
                [],
                [
                    'direction' => 'prev',
                    'oldid' => $oldid
                ] + $extraParams
            )
            : $context->msg( 'previousrevision' )->escaped();
        $prevdiff = $prevExist
            ? Linker::linkKnown(
                $this->getTitle(),
                $context->msg( 'diff' )->escaped(),
                [],
                [
                    'diff' => 'prev',
                    'oldid' => $oldid
                ] + $extraParams
            )
            : $context->msg( 'diff' )->escaped();
        $nextlink = $current
            ? $context->msg( 'nextrevision' )->escaped()
            : Linker::linkKnown(
                $this->getTitle(),
                $context->msg( 'nextrevision' )->escaped(),
                [],
                [
                    'direction' => 'next',
                    'oldid' => $oldid
                ] + $extraParams
            );
        $nextdiff = $current
            ? $context->msg( 'diff' )->escaped()
            : Linker::linkKnown(
                $this->getTitle(),
                $context->msg( 'diff' )->escaped(),
                [],
                [
                    'diff' => 'next',
                    'oldid' => $oldid
                ] + $extraParams
            );

        $cdel = Linker::getRevDeleteLink( $user, $revision, $this->getTitle() );
        if ( $cdel !== '' ) {
            $cdel .= ' ';
        }

        // the outer div is need for styling the revision info and nav in MobileFrontend
        $outputPage->addSubtitle( "<div class=\"mw-revision warningbox\">" . $revisionInfo .
            "<div id=\"mw-revision-nav\">" . $cdel .
            $context->msg( 'revision-nav' )->rawParams(
                $prevdiff, $prevlink, $lnk, $curdiff, $nextlink, $nextdiff
            )->escaped() . "</div></div>" );
    }

    public function viewRedirect( $target, $appendSubtitle = true, $forceKnown = false ) {
        $lang = $this->getTitle()->getPageLanguage();
        $out = $this->getContext()->getOutput();
        if ( $appendSubtitle ) {
            $out->addSubtitle( wfMessage( 'redirectpagesub' ) );
        }
        $out->addModuleStyles( 'mediawiki.action.view.redirectPage' );
        return static::getRedirectHeaderHtml( $lang, $target, $forceKnown );
    }

    public static function getRedirectHeaderHtml( Language $lang, $target, $forceKnown = false ) {
        if ( !is_array( $target ) ) {
            $target = [ $target ];
        }

        $html = '<ul class="redirectText">';
        foreach ( $target as $title ) {
            $html .= '<li>' . Linker::link(
                $title,
                htmlspecialchars( $title->getFullText() ),
                [],
                // Make sure wiki page redirects are not followed
                $title->isRedirect() ? [ 'redirect' => 'no' ] : [],
                ( $forceKnown ? [ 'known', 'noclasses' ] : [] )
            ) . '</li>';
        }
        $html .= '</ul>';

        $redirectToText = wfMessage( 'redirectto' )->inLanguage( $lang )->escaped();

        return '<div class="redirectMsg">' .
            '<p>' . $redirectToText . '</p>' .
            $html .
            '</div>';
    }

    public function addHelpLink( $to, $overrideBaseUrl = false ) {
        $msg = wfMessage(
            'namespace-' . $this->getTitle()->getNamespace() . '-helppage'
        );

        $out = $this->getContext()->getOutput();
        if ( !$msg->isDisabled() ) {
            $helpUrl = Skin::makeUrl( $msg->plain() );
            $out->addHelpLink( $helpUrl, true );
        } else {
            $out->addHelpLink( $to, $overrideBaseUrl );
        }
    }

    public function render() {
        $this->getContext()->getRequest()->response()->header( 'X-Robots-Tag: noindex' );
        $this->getContext()->getOutput()->setArticleBodyOnly( true );
        // We later set 'enableSectionEditLinks=false' based on this; also used by ImagePage
        $this->viewIsRenderAction = true;
        $this->view();
    }

    public function protect() {
        $form = new ProtectionForm( $this );
        $form->execute();
    }

    public function unprotect() {
        $this->protect();
    }

    public function delete() {
        # This code desperately needs to be totally rewritten

        $title = $this->getTitle();
        $context = $this->getContext();
        $user = $context->getUser();
        $request = $context->getRequest();

        # Check permissions
        $permissionErrors = $title->getUserPermissionsErrors( 'delete', $user );
        if ( count( $permissionErrors ) ) {
            throw new PermissionsError( 'delete', $permissionErrors );
        }

        # Read-only check...
        if ( wfReadOnly() ) {
            throw new ReadOnlyError;
        }

        # Better double-check that it hasn't been deleted yet!
        $this->mPage->loadPageData(
            $request->wasPosted() ? WikiPage::READ_LATEST : WikiPage::READ_NORMAL
        );
        if ( !$this->mPage->exists() ) {
            $deleteLogPage = new LogPage( 'delete' );
            $outputPage = $context->getOutput();
            $outputPage->setPageTitle( $context->msg( 'cannotdelete-title', $title->getPrefixedText() ) );
            $outputPage->wrapWikiMsg( "<div class=\"error mw-error-cannotdelete\">\n$1\n</div>",
                    [ 'cannotdelete', wfEscapeWikiText( $title->getPrefixedText() ) ]
                );
            $outputPage->addHTML(
                Xml::element( 'h2', null, $deleteLogPage->getName()->text() )
            );
            LogEventsList::showLogExtract(
                $outputPage,
                'delete',
                $title
            );

            return;
        }

        $deleteReasonList = $request->getText( 'wpDeleteReasonList', 'other' );
        $deleteReason = $request->getText( 'wpReason' );

        if ( $deleteReasonList == 'other' ) {
            $reason = $deleteReason;
        } elseif ( $deleteReason != '' ) {
            // Entry from drop down menu + additional comment
            $colonseparator = wfMessage( 'colon-separator' )->inContentLanguage()->text();
            $reason = $deleteReasonList . $colonseparator . $deleteReason;
        } else {
            $reason = $deleteReasonList;
        }

        if ( $request->wasPosted() && $user->matchEditToken( $request->getVal( 'wpEditToken' ),
            [ 'delete', $this->getTitle()->getPrefixedText() ] )
        ) {
            # Flag to hide all contents of the archived revisions

            $suppress = $request->getCheck( 'wpSuppress' ) && MediaWikiServices::getInstance()
                    ->getPermissionManager()
                    ->userHasRight( $user, 'suppressrevision' );

            $this->doDelete( $reason, $suppress );

            WatchAction::doWatchOrUnwatch( $request->getCheck( 'wpWatch' ), $title, $user );

            return;
        }

        // Generate deletion reason
        $hasHistory = false;
        if ( !$reason ) {
            try {
                $reason = $this->generateReason( $hasHistory );
            } catch ( Exception $e ) {
                # if a page is horribly broken, we still want to be able to
                # delete it. So be lenient about errors here.
                wfDebug( "Error while building auto delete summary: $e" );
                $reason = '';
            }
        }

        // If the page has a history, insert a warning
        if ( $hasHistory ) {
            $title = $this->getTitle();

            // The following can use the real revision count as this is only being shown for users
            // that can delete this page.
            // This, as a side-effect, also makes sure that the following query isn't being run for
            // pages with a larger history, unless the user has the 'bigdelete' right
            // (and is about to delete this page).
            $dbr = wfGetDB( DB_REPLICA );
            $revisions = $edits = (int)$dbr->selectField(
                'revision',
                'COUNT(rev_page)',
                [ 'rev_page' => $title->getArticleID() ],
                __METHOD__
            );

            // @todo i18n issue/patchwork message
            $context->getOutput()->addHTML(
                '<strong class="mw-delete-warning-revisions">' .
                $context->msg( 'historywarning' )->numParams( $revisions )->parse() .
                $context->msg( 'word-separator' )->escaped() . Linker::linkKnown( $title,
                    $context->msg( 'history' )->escaped(),
                    [],
                    [ 'action' => 'history' ] ) .
                '</strong>'
            );

            if ( $title->isBigDeletion() ) {
                global $wgDeleteRevisionsLimit;
                $context->getOutput()->wrapWikiMsg( "<div class='error'>\n$1\n</div>\n",
                    [
                        'delete-warning-toobig',
                        $context->getLanguage()->formatNum( $wgDeleteRevisionsLimit )
                    ]
                );
            }
        }

        $this->confirmDelete( $reason );
    }

    public function confirmDelete( $reason ) {
        wfDebug( "Article::confirmDelete\n" );

        $title = $this->getTitle();
        $ctx = $this->getContext();
        $outputPage = $ctx->getOutput();
        $outputPage->setPageTitle( wfMessage( 'delete-confirm', $title->getPrefixedText() ) );
        $outputPage->addBacklinkSubtitle( $title );
        $outputPage->setRobotPolicy( 'noindex,nofollow' );
        $outputPage->addModules( 'mediawiki.action.delete' );

        $backlinkCache = $title->getBacklinkCache();
        if ( $backlinkCache->hasLinks( 'pagelinks' ) || $backlinkCache->hasLinks( 'templatelinks' ) ) {
            $outputPage->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n",
                'deleting-backlinks-warning' );
        }

        $subpageQueryLimit = 51;
        $subpages = $title->getSubpages( $subpageQueryLimit );
        $subpageCount = count( $subpages );
        if ( $subpageCount > 0 ) {
            $outputPage->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n",
                [ 'deleting-subpages-warning', Message::numParam( $subpageCount ) ] );
        }
        $outputPage->addWikiMsg( 'confirmdeletetext' );

        Hooks::run( 'ArticleConfirmDelete', [ $this, $outputPage, &$reason ] );

        $user = $this->getContext()->getUser();
        $checkWatch = $user->getBoolOption( 'watchdeletion' ) || $user->isWatched( $title );

        $outputPage->enableOOUI();

        $fields = [];

        $options = Xml::listDropDownOptions(
            $ctx->msg( 'deletereason-dropdown' )->inContentLanguage()->text(),
            [ 'other' => $ctx->msg( 'deletereasonotherlist' )->inContentLanguage()->text() ]
        );
        $options = Xml::listDropDownOptionsOoui( $options );

        $fields[] = new OOUI\FieldLayout(
            new OOUI\DropdownInputWidget( [
                'name' => 'wpDeleteReasonList',
                'inputId' => 'wpDeleteReasonList',
                'tabIndex' => 1,
                'infusable' => true,
                'value' => '',
                'options' => $options
            ] ),
            [
                'label' => $ctx->msg( 'deletecomment' )->text(),
                'align' => 'top',
            ]
        );

        // HTML maxlength uses "UTF-16 code units", which means that characters outside BMP
        // (e.g. emojis) count for two each. This limit is overridden in JS to instead count
        // Unicode codepoints.
        $fields[] = new OOUI\FieldLayout(
            new OOUI\TextInputWidget( [
                'name' => 'wpReason',
                'inputId' => 'wpReason',
                'tabIndex' => 2,
                'maxLength' => CommentStore::COMMENT_CHARACTER_LIMIT,
                'infusable' => true,
                'value' => $reason,
                'autofocus' => true,
            ] ),
            [
                'label' => $ctx->msg( 'deleteotherreason' )->text(),
                'align' => 'top',
            ]
        );

        if ( $user->isLoggedIn() ) {
            $fields[] = new OOUI\FieldLayout(
                new OOUI\CheckboxInputWidget( [
                    'name' => 'wpWatch',
                    'inputId' => 'wpWatch',
                    'tabIndex' => 3,
                    'selected' => $checkWatch,
                ] ),
                [
                    'label' => $ctx->msg( 'watchthis' )->text(),
                    'align' => 'inline',
                    'infusable' => true,
                ]
            );
        }
        $permissionManager = MediaWikiServices::getInstance()->getPermissionManager();
        if ( $permissionManager->userHasRight( $user, 'suppressrevision' ) ) {
            $fields[] = new OOUI\FieldLayout(
                new OOUI\CheckboxInputWidget( [
                    'name' => 'wpSuppress',
                    'inputId' => 'wpSuppress',
                    'tabIndex' => 4,
                ] ),
                [
                    'label' => $ctx->msg( 'revdelete-suppress' )->text(),
                    'align' => 'inline',
                    'infusable' => true,
                ]
            );
        }

        $fields[] = new OOUI\FieldLayout(
            new OOUI\ButtonInputWidget( [
                'name' => 'wpConfirmB',
                'inputId' => 'wpConfirmB',
                'tabIndex' => 5,
                'value' => $ctx->msg( 'deletepage' )->text(),
                'label' => $ctx->msg( 'deletepage' )->text(),
                'flags' => [ 'primary', 'destructive' ],
                'type' => 'submit',
            ] ),
            [
                'align' => 'top',
            ]
        );

        $fieldset = new OOUI\FieldsetLayout( [
            'label' => $ctx->msg( 'delete-legend' )->text(),
            'id' => 'mw-delete-table',
            'items' => $fields,
        ] );

        $form = new OOUI\FormLayout( [
            'method' => 'post',
            'action' => $title->getLocalURL( 'action=delete' ),
            'id' => 'deleteconfirm',
        ] );
        $form->appendContent(
            $fieldset,
            new OOUI\HtmlSnippet(
                Html::hidden( 'wpEditToken', $user->getEditToken( [ 'delete', $title->getPrefixedText() ] ) )
            )
        );

        $outputPage->addHTML(
            new OOUI\PanelLayout( [
                'classes' => [ 'deletepage-wrapper' ],
                'expanded' => false,
                'padded' => true,
                'framed' => true,
                'content' => $form,
            ] )
        );

        if ( $permissionManager->userHasRight( $user, 'editinterface' ) ) {
            $link = Linker::linkKnown(
                $ctx->msg( 'deletereason-dropdown' )->inContentLanguage()->getTitle(),
                wfMessage( 'delete-edit-reasonlist' )->escaped(),
                [],
                [ 'action' => 'edit' ]
            );
            $outputPage->addHTML( '<p class="mw-delete-editreasons">' . $link . '</p>' );
        }

        $deleteLogPage = new LogPage( 'delete' );
        $outputPage->addHTML( Xml::element( 'h2', null, $deleteLogPage->getName()->text() ) );
        LogEventsList::showLogExtract( $outputPage, 'delete', $title );
    }

    public function doDelete( $reason, $suppress = false, $immediate = false ) {
        $error = '';
        $context = $this->getContext();
        $outputPage = $context->getOutput();
        $user = $context->getUser();
        $status = $this->mPage->doDeleteArticleReal( $reason, $suppress, 0, true, $error, $user,
            [], 'delete', $immediate );

        if ( $status->isOK() ) {
            $deleted = $this->getTitle()->getPrefixedText();

            $outputPage->setPageTitle( wfMessage( 'actioncomplete' ) );
            $outputPage->setRobotPolicy( 'noindex,nofollow' );

            if ( $status->isGood() ) {
                $loglink = '[[Special:Log/delete|' . wfMessage( 'deletionlog' )->text() . ']]';
                $outputPage->addWikiMsg( 'deletedtext', wfEscapeWikiText( $deleted ), $loglink );
                Hooks::run( 'ArticleDeleteAfterSuccess', [ $this->getTitle(), $outputPage ] );
            } else {
                $outputPage->addWikiMsg( 'delete-scheduled', wfEscapeWikiText( $deleted ) );
            }

            $outputPage->returnToMain( false );
        } else {
            $outputPage->setPageTitle(
                wfMessage( 'cannotdelete-title',
                    $this->getTitle()->getPrefixedText() )
            );

            if ( $error == '' ) {
                $outputPage->wrapWikiTextAsInterface(
                    'error mw-error-cannotdelete',
                    $status->getWikiText( false, false, $context->getLanguage() )
                );
                $deleteLogPage = new LogPage( 'delete' );
                $outputPage->addHTML( Xml::element( 'h2', null, $deleteLogPage->getName()->text() ) );

                LogEventsList::showLogExtract(
                    $outputPage,
                    'delete',
                    $this->getTitle()
                );
            } else {
                $outputPage->addHTML( $error );
            }
        }
    }

    /* Caching functions */

    protected function tryFileCache() {
        static $called = false;

        if ( $called ) {
            wfDebug( "Article::tryFileCache(): called twice!?\n" );
            return false;
        }

        $called = true;
        if ( $this->isFileCacheable() ) {
            $cache = new HTMLFileCache( $this->getTitle(), 'view' );
            if ( $cache->isCacheGood( $this->mPage->getTouched() ) ) {
                wfDebug( "Article::tryFileCache(): about to load file\n" );
                $cache->loadFromFileCache( $this->getContext() );
                return true;
            } else {
                wfDebug( "Article::tryFileCache(): starting buffer\n" );
                ob_start( [ &$cache, 'saveToFileCache' ] );
            }
        } else {
            wfDebug( "Article::tryFileCache(): not cacheable\n" );
        }

        return false;
    }

    public function isFileCacheable( $mode = HTMLFileCache::MODE_NORMAL ) {
        $cacheable = false;

        if ( HTMLFileCache::useFileCache( $this->getContext(), $mode ) ) {
            $cacheable = $this->mPage->getId()
                && !$this->mRedirectedFrom && !$this->getTitle()->isRedirect();
            // Extension may have reason to disable file caching on some pages.
            if ( $cacheable ) {
                // Avoid PHP 7.1 warning of passing $this by reference
                $articlePage = $this;
                $cacheable = Hooks::run( 'IsFileCacheable', [ &$articlePage ] );
            }
        }

        return $cacheable;
    }

    public function getParserOutput( $oldid = null, User $user = null ) {
        // XXX: bypasses mParserOptions and thus setParserOptions()

        if ( $user === null ) {
            $parserOptions = $this->getParserOptions();
        } else {
            $parserOptions = $this->mPage->makeParserOptions( $user );
        }

        return $this->mPage->getParserOutput( $parserOptions, $oldid );
    }

    public function setParserOptions( ParserOptions $options ) {
        if ( $this->mParserOptions ) {
            throw new MWException( "can't change parser options after they have already been set" );
        }

        // clone, so if $options is modified later, it doesn't confuse the parser cache.
        $this->mParserOptions = clone $options;
    }

    public function getParserOptions() {
        if ( !$this->mParserOptions ) {
            $this->mParserOptions = $this->mPage->makeParserOptions( $this->getContext() );
        }
        // Clone to allow modifications of the return value without affecting cache
        return clone $this->mParserOptions;
    }

    public function setContext( $context ) {
        $this->mContext = $context;
    }

    public function getContext() {
        if ( $this->mContext instanceof IContextSource ) {
            return $this->mContext;
        } else {
            wfDebug( __METHOD__ . " called and \$mContext is null. " .
                "Return RequestContext::getMain(); for sanity\n" );
            return RequestContext::getMain();
        }
    }

    public function __get( $fname ) {
        if ( property_exists( $this->mPage, $fname ) ) {
            # wfWarn( "Access to raw $fname field " . __CLASS__ );
            return $this->mPage->$fname;
        }
        trigger_error( 'Inaccessible property via __get(): ' . $fname, E_USER_NOTICE );
    }

    public function __set( $fname, $fvalue ) {
        if ( property_exists( $this->mPage, $fname ) ) {
            # wfWarn( "Access to raw $fname field of " . __CLASS__ );
            $this->mPage->$fname = $fvalue;
        // Note: extensions may want to toss on new fields
        } elseif ( !in_array( $fname, [ 'mContext', 'mPage' ] ) ) {
            $this->mPage->$fname = $fvalue;
        } else {
            trigger_error( 'Inaccessible property via __set(): ' . $fname, E_USER_NOTICE );
        }
    }

    public function checkFlags( $flags ) {
        return $this->mPage->checkFlags( $flags );
    }

    public function checkTouched() {
        return $this->mPage->checkTouched();
    }

    public function clearPreparedEdit() {
        $this->mPage->clearPreparedEdit();
    }

    public function doDeleteArticleReal(
        $reason, $suppress = false, $u1 = null, $u2 = null, &$error = '', User $user = null,
        $tags = [], $immediate = false
    ) {
        return $this->mPage->doDeleteArticleReal(
            $reason, $suppress, $u1, $u2, $error, $user, $tags, 'delete', $immediate
        );
    }

    public function doDeleteUpdates(
        $id,
        Content $content = null,
        $revision = null,
        User $user = null
    ) {
        $this->mPage->doDeleteUpdates( $id, $content, $revision, $user );
    }

    public function doEditContent( Content $content, $summary, $flags = 0, $originalRevId = false,
        User $user = null, $serialFormat = null
    ) {
        wfDeprecated( __METHOD__, '1.29' );
        return $this->mPage->doEditContent( $content, $summary, $flags, $originalRevId,
            $user, $serialFormat
        );
    }

    public function doEditUpdates( Revision $revision, User $user, array $options = [] ) {
        return $this->mPage->doEditUpdates( $revision, $user, $options );
    }

    public function doPurge() {
        return $this->mPage->doPurge();
    }

    public function doViewUpdates( User $user, $oldid = 0 ) {
        $this->mPage->doViewUpdates( $user, $oldid );
    }

    public function exists() {
        return $this->mPage->exists();
    }

    public function followRedirect() {
        return $this->mPage->followRedirect();
    }

    public function getActionOverrides() {
        return $this->mPage->getActionOverrides();
    }

    public function getAutoDeleteReason( &$hasHistory ) {
        return $this->mPage->getAutoDeleteReason( $hasHistory );
    }

    public function getCategories() {
        return $this->mPage->getCategories();
    }

    public function getComment( $audience = RevisionRecord::FOR_PUBLIC, User $user = null ) {
        return $this->mPage->getComment( $audience, $user );
    }

    public function getContentHandler() {
        return $this->mPage->getContentHandler();
    }

    public function getContentModel() {
        return $this->mPage->getContentModel();
    }

    public function getContributors() {
        return $this->mPage->getContributors();
    }

    public function getCreator( $audience = RevisionRecord::FOR_PUBLIC, User $user = null ) {
        return $this->mPage->getCreator( $audience, $user );
    }

    public function getDeletionUpdates( Content $content = null ) {
        return $this->mPage->getDeletionUpdates( $content );
    }

    public function getHiddenCategories() {
        return $this->mPage->getHiddenCategories();
    }

    public function getId() {
        return $this->mPage->getId();
    }

    public function getLatest() {
        return $this->mPage->getLatest();
    }

    public function getLinksTimestamp() {
        return $this->mPage->getLinksTimestamp();
    }

    public function getMinorEdit() {
        return $this->mPage->getMinorEdit();
    }

    public function getOldestRevision() {
        return $this->mPage->getOldestRevision();
    }

    public function getRedirectTarget() {
        return $this->mPage->getRedirectTarget();
    }

    public function getRedirectURL( $rt ) {
        return $this->mPage->getRedirectURL( $rt );
    }

    public function getRevision() {
        return $this->mPage->getRevision();
    }

    public function getTimestamp() {
        return $this->mPage->getTimestamp();
    }

    public function getTouched() {
        return $this->mPage->getTouched();
    }

    public function getUndoContent( Revision $undo, Revision $undoafter = null ) {
        return $this->mPage->getUndoContent( $undo, $undoafter );
    }

    public function getUser( $audience = RevisionRecord::FOR_PUBLIC, User $user = null ) {
        return $this->mPage->getUser( $audience, $user );
    }

    public function getUserText( $audience = RevisionRecord::FOR_PUBLIC, User $user = null ) {
        return $this->mPage->getUserText( $audience, $user );
    }

    public function hasViewableContent() {
        return $this->mPage->hasViewableContent();
    }

    public function insertOn( $dbw, $pageId = null ) {
        return $this->mPage->insertOn( $dbw, $pageId );
    }

    public function insertProtectNullRevision( $revCommentMsg, array $limit,
        array $expiry, $cascade, $reason, $user = null
    ) {
        return $this->mPage->insertProtectNullRevision( $revCommentMsg, $limit,
            $expiry, $cascade, $reason, $user
        );
    }

    public function insertRedirect() {
        return $this->mPage->insertRedirect();
    }

    public function insertRedirectEntry( Title $rt, $oldLatest = null ) {
        return $this->mPage->insertRedirectEntry( $rt, $oldLatest );
    }

    public function isCountable( $editInfo = false ) {
        return $this->mPage->isCountable( $editInfo );
    }

    public function isRedirect() {
        return $this->mPage->isRedirect();
    }

    public function loadFromRow( $data, $from ) {
        return $this->mPage->loadFromRow( $data, $from );
    }

    public function loadPageData( $from = 'fromdb' ) {
        $this->mPage->loadPageData( $from );
    }

    public function lockAndGetLatest() {
        return $this->mPage->lockAndGetLatest();
    }

    public function makeParserOptions( $context ) {
        return $this->mPage->makeParserOptions( $context );
    }

    public function pageDataFromId( $dbr, $id, $options = [] ) {
        return $this->mPage->pageDataFromId( $dbr, $id, $options );
    }

    public function pageDataFromTitle( $dbr, $title, $options = [] ) {
        return $this->mPage->pageDataFromTitle( $dbr, $title, $options );
    }

    public function prepareContentForEdit(
        Content $content, $revision = null, User $user = null,
        $serialFormat = null, $useCache = true
    ) {
        return $this->mPage->prepareContentForEdit(
            $content, $revision, $user,
            $serialFormat, $useCache
        );
    }

    public function protectDescription( array $limit, array $expiry ) {
        return $this->mPage->protectDescription( $limit, $expiry );
    }

    public function protectDescriptionLog( array $limit, array $expiry ) {
        return $this->mPage->protectDescriptionLog( $limit, $expiry );
    }

    public function replaceSectionAtRev( $sectionId, Content $sectionContent,
        $sectionTitle = '', $baseRevId = null
    ) {
        return $this->mPage->replaceSectionAtRev( $sectionId, $sectionContent,
            $sectionTitle, $baseRevId
        );
    }

    public function replaceSectionContent(
        $sectionId, Content $sectionContent, $sectionTitle = '', $edittime = null
    ) {
        return $this->mPage->replaceSectionContent(
            $sectionId, $sectionContent, $sectionTitle, $edittime
        );
    }

    public function setTimestamp( $ts ) {
        $this->mPage->setTimestamp( $ts );
    }

    public function shouldCheckParserCache( ParserOptions $parserOptions, $oldId ) {
        return $this->mPage->shouldCheckParserCache( $parserOptions, $oldId );
    }

    public function supportsSections() {
        return $this->mPage->supportsSections();
    }

    public function triggerOpportunisticLinksUpdate( ParserOutput $parserOutput ) {
        return $this->mPage->triggerOpportunisticLinksUpdate( $parserOutput );
    }

    public function updateCategoryCounts( array $added, array $deleted, $id = 0 ) {
        return $this->mPage->updateCategoryCounts( $added, $deleted, $id );
    }

    public function updateIfNewerOn( $dbw, $revision ) {
        return $this->mPage->updateIfNewerOn( $dbw, $revision );
    }

    public function updateRedirectOn( $dbw, $redirectTitle, $lastRevIsRedirect = null ) {
        return $this->mPage->updateRedirectOn( $dbw, $redirectTitle, $lastRevIsRedirect );
    }

    public function updateRevisionOn( $dbw, $revision, $lastRevision = null,
        $lastRevIsRedirect = null
    ) {
        return $this->mPage->updateRevisionOn( $dbw, $revision, $lastRevision,
            $lastRevIsRedirect
        );
    }

    public function doUpdateRestrictions( array $limit, array $expiry, &$cascade,
        $reason, User $user
    ) {
        return $this->mPage->doUpdateRestrictions( $limit, $expiry, $cascade, $reason, $user );
    }

    public function updateRestrictions( $limit = [], $reason = '',
        &$cascade = 0, $expiry = []
    ) {
        return $this->mPage->doUpdateRestrictions(
            $limit,
            $expiry,
            $cascade,
            $reason,
            $this->getContext()->getUser()
        );
    }

    public function doDeleteArticle(
        $reason, $suppress = false, $u1 = null, $u2 = null, &$error = '', $immediate = false
    ) {
        return $this->mPage->doDeleteArticle( $reason, $suppress, $u1, $u2, $error,
            null, $immediate );
    }

    public function doRollback( $fromP, $summary, $token, $bot, &$resultDetails, User $user = null ) {
        if ( !$user ) {
            $user = $this->getContext()->getUser();
        }

        return $this->mPage->doRollback( $fromP, $summary, $token, $bot, $resultDetails, $user );
    }

    public function commitRollback( $fromP, $summary, $bot, &$resultDetails, User $guser = null ) {
        if ( !$guser ) {
            $guser = $this->getContext()->getUser();
        }

        return $this->mPage->commitRollback( $fromP, $summary, $bot, $resultDetails, $guser );
    }

    public function generateReason( &$hasHistory ) {
        $title = $this->mPage->getTitle();
        $handler = ContentHandler::getForTitle( $title );
        return $handler->getAutoDeleteReason( $title, $hasHistory );
    }

    // ******
}