WikiPage.php

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<?php
use MediaWiki\Edit\PreparedEdit;
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\MediaWikiServices;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Revision\RevisionRenderer;
use MediaWiki\Revision\RevisionStore;
use MediaWiki\Revision\SlotRecord;
use MediaWiki\Storage\DerivedPageDataUpdater;
use MediaWiki\Storage\PageUpdater;
use MediaWiki\Storage\RevisionSlotsUpdate;
use Wikimedia\Assert\Assert;
use Wikimedia\Rdbms\FakeResultWrapper;
use Wikimedia\Rdbms\IDatabase;
use Wikimedia\Rdbms\LoadBalancer;
 
class WikiPage implements Page, IDBAccessObject {
    // Constants for $mDataLoadedFrom and related
 
    public $mTitle = null;
 
    public $mDataLoaded = false;         // !< Boolean
    public $mIsRedirect = false;         // !< Boolean
    public $mLatest = false;             // !< Integer (false means "not loaded")
    public $mPreparedEdit = false;
 
    protected $mId = null;
 
    protected $mDataLoadedFrom = self::READ_NONE;
 
    protected $mRedirectTarget = null;
 
    protected $mLastRevision = null;
 
    protected $mTimestamp = '';
 
    protected $mTouched = '19700101000000';
 
    protected $mLinksUpdated = '19700101000000';
 
    private $derivedDataUpdater = null;
 
    public function __construct( Title $title ) {
        $this->mTitle = $title;
    }
 
    public function __clone() {
        $this->mTitle = clone $this->mTitle;
    }
 
    public static function factory( Title $title ) {
        $ns = $title->getNamespace();
 
        if ( $ns == NS_MEDIA ) {
            throw new MWException( "NS_MEDIA is a virtual namespace; use NS_FILE." );
        } elseif ( $ns < 0 ) {
            throw new MWException( "Invalid or virtual namespace $ns given." );
        }
 
        $page = null;
        if ( !Hooks::run( 'WikiPageFactory', [ $title, &$page ] ) ) {
            return $page;
        }
 
        switch ( $ns ) {
            case NS_FILE:
                $page = new WikiFilePage( $title );
                break;
            case NS_CATEGORY:
                $page = new WikiCategoryPage( $title );
                break;
            default:
                $page = new WikiPage( $title );
        }
 
        return $page;
    }
 
    public static function newFromID( $id, $from = 'fromdb' ) {
        // page ids are never 0 or negative, see T63166
        if ( $id < 1 ) {
            return null;
        }
 
        $from = self::convertSelectType( $from );
        $db = wfGetDB( $from === self::READ_LATEST ? DB_MASTER : DB_REPLICA );
        $pageQuery = self::getQueryInfo();
        $row = $db->selectRow(
            $pageQuery['tables'], $pageQuery['fields'], [ 'page_id' => $id ], __METHOD__,
            [], $pageQuery['joins']
        );
        if ( !$row ) {
            return null;
        }
        return self::newFromRow( $row, $from );
    }
 
    public static function newFromRow( $row, $from = 'fromdb' ) {
        $page = self::factory( Title::newFromRow( $row ) );
        $page->loadFromRow( $row, $from );
        return $page;
    }
 
    protected static function convertSelectType( $type ) {
        switch ( $type ) {
            case 'fromdb':
                return self::READ_NORMAL;
            case 'fromdbmaster':
                return self::READ_LATEST;
            case 'forupdate':
                return self::READ_LOCKING;
            default:
                // It may already be an integer or whatever else
                return $type;
        }
    }
 
    private function getRevisionStore() {
        return MediaWikiServices::getInstance()->getRevisionStore();
    }
 
    private function getRevisionRenderer() {
        return MediaWikiServices::getInstance()->getRevisionRenderer();
    }
 
    private function getParserCache() {
        return MediaWikiServices::getInstance()->getParserCache();
    }
 
    private function getDBLoadBalancer() {
        return MediaWikiServices::getInstance()->getDBLoadBalancer();
    }
 
    public function getActionOverrides() {
        return $this->getContentHandler()->getActionOverrides();
    }
 
    public function getContentHandler() {
        return ContentHandler::getForModelID( $this->getContentModel() );
    }
 
    public function getTitle() {
        return $this->mTitle;
    }
 
    public function clear() {
        $this->mDataLoaded = false;
        $this->mDataLoadedFrom = self::READ_NONE;
 
        $this->clearCacheFields();
    }
 
    protected function clearCacheFields() {
        $this->mId = null;
        $this->mRedirectTarget = null; // Title object if set
        $this->mLastRevision = null; // Latest revision
        $this->mTouched = '19700101000000';
        $this->mLinksUpdated = '19700101000000';
        $this->mTimestamp = '';
        $this->mIsRedirect = false;
        $this->mLatest = false;
        // T59026: do not clear $this->derivedDataUpdater since getDerivedDataUpdater() already
        // checks the requested rev ID and content against the cached one. For most
        // content types, the output should not change during the lifetime of this cache.
        // Clearing it can cause extra parses on edit for no reason.
    }
 
    public function clearPreparedEdit() {
        $this->mPreparedEdit = false;
    }
 
    public static function selectFields() {
        global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 
        wfDeprecated( __METHOD__, '1.31' );
 
        $fields = [
            'page_id',
            'page_namespace',
            'page_title',
            'page_restrictions',
            'page_is_redirect',
            'page_is_new',
            'page_random',
            'page_touched',
            'page_links_updated',
            'page_latest',
            'page_len',
        ];
 
        if ( $wgContentHandlerUseDB ) {
            $fields[] = 'page_content_model';
        }
 
        if ( $wgPageLanguageUseDB ) {
            $fields[] = 'page_lang';
        }
 
        return $fields;
    }
 
    public static function getQueryInfo() {
        global $wgContentHandlerUseDB, $wgPageLanguageUseDB;
 
        $ret = [
            'tables' => [ 'page' ],
            'fields' => [
                'page_id',
                'page_namespace',
                'page_title',
                'page_restrictions',
                'page_is_redirect',
                'page_is_new',
                'page_random',
                'page_touched',
                'page_links_updated',
                'page_latest',
                'page_len',
            ],
            'joins' => [],
        ];
 
        if ( $wgContentHandlerUseDB ) {
            $ret['fields'][] = 'page_content_model';
        }
 
        if ( $wgPageLanguageUseDB ) {
            $ret['fields'][] = 'page_lang';
        }
 
        return $ret;
    }
 
    protected function pageData( $dbr, $conditions, $options = [] ) {
        $pageQuery = self::getQueryInfo();
 
        // Avoid PHP 7.1 warning of passing $this by reference
        $wikiPage = $this;
 
        Hooks::run( 'ArticlePageDataBefore', [
            &$wikiPage, &$pageQuery['fields'], &$pageQuery['tables'], &$pageQuery['joins']
        ] );
 
        $row = $dbr->selectRow(
            $pageQuery['tables'],
            $pageQuery['fields'],
            $conditions,
            __METHOD__,
            $options,
            $pageQuery['joins']
        );
 
        Hooks::run( 'ArticlePageDataAfter', [ &$wikiPage, &$row ] );
 
        return $row;
    }
 
    public function pageDataFromTitle( $dbr, $title, $options = [] ) {
        return $this->pageData( $dbr, [
            'page_namespace' => $title->getNamespace(),
            'page_title' => $title->getDBkey() ], $options );
    }
 
    public function pageDataFromId( $dbr, $id, $options = [] ) {
        return $this->pageData( $dbr, [ 'page_id' => $id ], $options );
    }
 
    public function loadPageData( $from = 'fromdb' ) {
        $from = self::convertSelectType( $from );
        if ( is_int( $from ) && $from <= $this->mDataLoadedFrom ) {
            // We already have the data from the correct location, no need to load it twice.
            return;
        }
 
        if ( is_int( $from ) ) {
            list( $index, $opts ) = DBAccessObjectUtils::getDBOptions( $from );
            $loadBalancer = $this->getDBLoadBalancer();
            $db = $loadBalancer->getConnection( $index );
            $data = $this->pageDataFromTitle( $db, $this->mTitle, $opts );
 
            if ( !$data
                && $index == DB_REPLICA
                && $loadBalancer->getServerCount() > 1
                && $loadBalancer->hasOrMadeRecentMasterChanges()
            ) {
                $from = self::READ_LATEST;
                list( $index, $opts ) = DBAccessObjectUtils::getDBOptions( $from );
                $db = $loadBalancer->getConnection( $index );
                $data = $this->pageDataFromTitle( $db, $this->mTitle, $opts );
            }
        } else {
            // No idea from where the caller got this data, assume replica DB.
            $data = $from;
            $from = self::READ_NORMAL;
        }
 
        $this->loadFromRow( $data, $from );
    }
 
    public function wasLoadedFrom( $from ) {
        $from = self::convertSelectType( $from );
 
        if ( !is_int( $from ) ) {
            // No idea from where the caller got this data, assume replica DB.
            $from = self::READ_NORMAL;
        }
 
        if ( is_int( $from ) && $from <= $this->mDataLoadedFrom ) {
            return true;
        }
 
        return false;
    }
 
    public function loadFromRow( $data, $from ) {
        $lc = MediaWikiServices::getInstance()->getLinkCache();
        $lc->clearLink( $this->mTitle );
 
        if ( $data ) {
            $lc->addGoodLinkObjFromRow( $this->mTitle, $data );
 
            $this->mTitle->loadFromRow( $data );
 
            // Old-fashioned restrictions
            $this->mTitle->loadRestrictions( $data->page_restrictions );
 
            $this->mId = intval( $data->page_id );
            $this->mTouched = wfTimestamp( TS_MW, $data->page_touched );
            $this->mLinksUpdated = wfTimestampOrNull( TS_MW, $data->page_links_updated );
            $this->mIsRedirect = intval( $data->page_is_redirect );
            $this->mLatest = intval( $data->page_latest );
            // T39225: $latest may no longer match the cached latest Revision object.
            // Double-check the ID of any cached latest Revision object for consistency.
            if ( $this->mLastRevision && $this->mLastRevision->getId() != $this->mLatest ) {
                $this->mLastRevision = null;
                $this->mTimestamp = '';
            }
        } else {
            $lc->addBadLinkObj( $this->mTitle );
 
            $this->mTitle->loadFromRow( false );
 
            $this->clearCacheFields();
 
            $this->mId = 0;
        }
 
        $this->mDataLoaded = true;
        $this->mDataLoadedFrom = self::convertSelectType( $from );
    }
 
    public function getId() {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return $this->mId;
    }
 
    public function exists() {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return $this->mId > 0;
    }
 
    public function hasViewableContent() {
        return $this->mTitle->isKnown();
    }
 
    public function isRedirect() {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
 
        return (bool)$this->mIsRedirect;
    }
 
    public function getContentModel() {
        if ( $this->exists() ) {
            $cache = ObjectCache::getMainWANInstance();
 
            return $cache->getWithSetCallback(
                $cache->makeKey( 'page-content-model', $this->getLatest() ),
                $cache::TTL_MONTH,
                function () {
                    $rev = $this->getRevision();
                    if ( $rev ) {
                        // Look at the revision's actual content model
                        return $rev->getContentModel();
                    } else {
                        $title = $this->mTitle->getPrefixedDBkey();
                        wfWarn( "Page $title exists but has no (visible) revisions!" );
                        return $this->mTitle->getContentModel();
                    }
                }
            );
        }
 
        // use the default model for this page
        return $this->mTitle->getContentModel();
    }
 
    public function checkTouched() {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return ( $this->mId && !$this->mIsRedirect );
    }
 
    public function getTouched() {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return $this->mTouched;
    }
 
    public function getLinksTimestamp() {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return $this->mLinksUpdated;
    }
 
    public function getLatest() {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return (int)$this->mLatest;
    }
 
    public function getOldestRevision() {
        // Try using the replica DB first, then try the master
        $rev = $this->mTitle->getFirstRevision();
        if ( !$rev ) {
            $rev = $this->mTitle->getFirstRevision( Title::GAID_FOR_UPDATE );
        }
        return $rev;
    }
 
    protected function loadLastEdit() {
        if ( $this->mLastRevision !== null ) {
            return; // already loaded
        }
 
        $latest = $this->getLatest();
        if ( !$latest ) {
            return; // page doesn't exist or is missing page_latest info
        }
 
        if ( $this->mDataLoadedFrom == self::READ_LOCKING ) {
            // T39225: if session S1 loads the page row FOR UPDATE, the result always
            // includes the latest changes committed. This is true even within REPEATABLE-READ
            // transactions, where S1 normally only sees changes committed before the first S1
            // SELECT. Thus we need S1 to also gets the revision row FOR UPDATE; otherwise, it
            // may not find it since a page row UPDATE and revision row INSERT by S2 may have
            // happened after the first S1 SELECT.
            // https://dev.mysql.com/doc/refman/5.0/en/set-transaction.html#isolevel_repeatable-read
            $flags = Revision::READ_LOCKING;
            $revision = Revision::newFromPageId( $this->getId(), $latest, $flags );
        } elseif ( $this->mDataLoadedFrom == self::READ_LATEST ) {
            // Bug T93976: if page_latest was loaded from the master, fetch the
            // revision from there as well, as it may not exist yet on a replica DB.
            // Also, this keeps the queries in the same REPEATABLE-READ snapshot.
            $flags = Revision::READ_LATEST;
            $revision = Revision::newFromPageId( $this->getId(), $latest, $flags );
        } else {
            $dbr = wfGetDB( DB_REPLICA );
            $revision = Revision::newKnownCurrent( $dbr, $this->getTitle(), $latest );
        }
 
        if ( $revision ) { // sanity
            $this->setLastEdit( $revision );
        }
    }
 
    protected function setLastEdit( Revision $revision ) {
        $this->mLastRevision = $revision;
        $this->mTimestamp = $revision->getTimestamp();
    }
 
    public function getRevision() {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            return $this->mLastRevision;
        }
        return null;
    }
 
    public function getRevisionRecord() {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            return $this->mLastRevision->getRevisionRecord();
        }
        return null;
    }
 
    public function getContent( $audience = Revision::FOR_PUBLIC, User $user = null ) {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            return $this->mLastRevision->getContent( $audience, $user );
        }
        return null;
    }
 
    public function getTimestamp() {
        // Check if the field has been filled by WikiPage::setTimestamp()
        if ( !$this->mTimestamp ) {
            $this->loadLastEdit();
        }
 
        return wfTimestamp( TS_MW, $this->mTimestamp );
    }
 
    public function setTimestamp( $ts ) {
        $this->mTimestamp = wfTimestamp( TS_MW, $ts );
    }
 
    public function getUser( $audience = Revision::FOR_PUBLIC, User $user = null ) {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            return $this->mLastRevision->getUser( $audience, $user );
        } else {
            return -1;
        }
    }
 
    public function getCreator( $audience = Revision::FOR_PUBLIC, User $user = null ) {
        $revision = $this->getOldestRevision();
        if ( $revision ) {
            $userName = $revision->getUserText( $audience, $user );
            return User::newFromName( $userName, false );
        } else {
            return null;
        }
    }
 
    public function getUserText( $audience = Revision::FOR_PUBLIC, User $user = null ) {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            return $this->mLastRevision->getUserText( $audience, $user );
        } else {
            return '';
        }
    }
 
    public function getComment( $audience = Revision::FOR_PUBLIC, User $user = null ) {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            return $this->mLastRevision->getComment( $audience, $user );
        } else {
            return '';
        }
    }
 
    public function getMinorEdit() {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            return $this->mLastRevision->isMinor();
        } else {
            return false;
        }
    }
 
    public function isCountable( $editInfo = false ) {
        global $wgArticleCountMethod;
 
        // NOTE: Keep in sync with DerivedPageDataUpdater::isCountable.
 
        if ( !$this->mTitle->isContentPage() ) {
            return false;
        }
 
        if ( $editInfo ) {
            // NOTE: only the main slot can make a page a redirect
            $content = $editInfo->pstContent;
        } else {
            $content = $this->getContent();
        }
 
        if ( !$content || $content->isRedirect() ) {
            return false;
        }
 
        $hasLinks = null;
 
        if ( $wgArticleCountMethod === 'link' ) {
            // nasty special case to avoid re-parsing to detect links
 
            if ( $editInfo ) {
                // ParserOutput::getLinks() is a 2D array of page links, so
                // to be really correct we would need to recurse in the array
                // but the main array should only have items in it if there are
                // links.
                $hasLinks = (bool)count( $editInfo->output->getLinks() );
            } else {
                // NOTE: keep in sync with revisionRenderer::getLinkCount
                $hasLinks = (bool)wfGetDB( DB_REPLICA )->selectField( 'pagelinks', 1,
                    [ 'pl_from' => $this->getId() ], __METHOD__ );
            }
        }
 
        return $content->isCountable( $hasLinks );
    }
 
    public function getRedirectTarget() {
        if ( !$this->mTitle->isRedirect() ) {
            return null;
        }
 
        if ( $this->mRedirectTarget !== null ) {
            return $this->mRedirectTarget;
        }
 
        // Query the redirect table
        $dbr = wfGetDB( DB_REPLICA );
        $row = $dbr->selectRow( 'redirect',
            [ 'rd_namespace', 'rd_title', 'rd_fragment', 'rd_interwiki' ],
            [ 'rd_from' => $this->getId() ],
            __METHOD__
        );
 
        // rd_fragment and rd_interwiki were added later, populate them if empty
        if ( $row && !is_null( $row->rd_fragment ) && !is_null( $row->rd_interwiki ) ) {
            // (T203942) We can't redirect to Media namespace because it's virtual.
            // We don't want to modify Title objects farther down the
            // line. So, let's fix this here by changing to File namespace.
            if ( $row->rd_namespace == NS_MEDIA ) {
                $namespace = NS_FILE;
            } else {
                $namespace = $row->rd_namespace;
            }
            $this->mRedirectTarget = Title::makeTitle(
                $namespace, $row->rd_title,
                $row->rd_fragment, $row->rd_interwiki
            );
            return $this->mRedirectTarget;
        }
 
        // This page doesn't have an entry in the redirect table
        $this->mRedirectTarget = $this->insertRedirect();
        return $this->mRedirectTarget;
    }
 
    public function insertRedirect() {
        $content = $this->getContent();
        $retval = $content ? $content->getUltimateRedirectTarget() : null;
        if ( !$retval ) {
            return null;
        }
 
        // Update the DB post-send if the page has not cached since now
        $latest = $this->getLatest();
        DeferredUpdates::addCallableUpdate(
            function () use ( $retval, $latest ) {
                $this->insertRedirectEntry( $retval, $latest );
            },
            DeferredUpdates::POSTSEND,
            wfGetDB( DB_MASTER )
        );
 
        return $retval;
    }
 
    public function insertRedirectEntry( Title $rt, $oldLatest = null ) {
        $dbw = wfGetDB( DB_MASTER );
        $dbw->startAtomic( __METHOD__ );
 
        if ( !$oldLatest || $oldLatest == $this->lockAndGetLatest() ) {
            $dbw->upsert(
                'redirect',
                [
                    'rd_from' => $this->getId(),
                    'rd_namespace' => $rt->getNamespace(),
                    'rd_title' => $rt->getDBkey(),
                    'rd_fragment' => $rt->getFragment(),
                    'rd_interwiki' => $rt->getInterwiki(),
                ],
                [ 'rd_from' ],
                [
                    'rd_namespace' => $rt->getNamespace(),
                    'rd_title' => $rt->getDBkey(),
                    'rd_fragment' => $rt->getFragment(),
                    'rd_interwiki' => $rt->getInterwiki(),
                ],
                __METHOD__
            );
        }
 
        $dbw->endAtomic( __METHOD__ );
    }
 
    public function followRedirect() {
        return $this->getRedirectURL( $this->getRedirectTarget() );
    }
 
    public function getRedirectURL( $rt ) {
        if ( !$rt ) {
            return false;
        }
 
        if ( $rt->isExternal() ) {
            if ( $rt->isLocal() ) {
                // Offsite wikis need an HTTP redirect.
                // This can be hard to reverse and may produce loops,
                // so they may be disabled in the site configuration.
                $source = $this->mTitle->getFullURL( 'redirect=no' );
                return $rt->getFullURL( [ 'rdfrom' => $source ] );
            } else {
                // External pages without "local" bit set are not valid
                // redirect targets
                return false;
            }
        }
 
        if ( $rt->isSpecialPage() ) {
            // Gotta handle redirects to special pages differently:
            // Fill the HTTP response "Location" header and ignore the rest of the page we're on.
            // Some pages are not valid targets.
            if ( $rt->isValidRedirectTarget() ) {
                return $rt->getFullURL();
            } else {
                return false;
            }
        }
 
        return $rt;
    }
 
    public function getContributors() {
        // @todo: This is expensive; cache this info somewhere.
 
        $dbr = wfGetDB( DB_REPLICA );
 
        $actorMigration = ActorMigration::newMigration();
        $actorQuery = $actorMigration->getJoin( 'rev_user' );
 
        $tables = array_merge( [ 'revision' ], $actorQuery['tables'], [ 'user' ] );
 
        $fields = [
            'user_id' => $actorQuery['fields']['rev_user'],
            'user_name' => $actorQuery['fields']['rev_user_text'],
            'actor_id' => $actorQuery['fields']['rev_actor'],
            'user_real_name' => 'MIN(user_real_name)',
            'timestamp' => 'MAX(rev_timestamp)',
        ];
 
        $conds = [ 'rev_page' => $this->getId() ];
 
        // The user who made the top revision gets credited as "this page was last edited by
        // John, based on contributions by Tom, Dick and Harry", so don't include them twice.
        $user = $this->getUser()
            ? User::newFromId( $this->getUser() )
            : User::newFromName( $this->getUserText(), false );
        $conds[] = 'NOT(' . $actorMigration->getWhere( $dbr, 'rev_user', $user )['conds'] . ')';
 
        // Username hidden?
        $conds[] = "{$dbr->bitAnd( 'rev_deleted', Revision::DELETED_USER )} = 0";
 
        $jconds = [
            'user' => [ 'LEFT JOIN', $actorQuery['fields']['rev_user'] . ' = user_id' ],
        ] + $actorQuery['joins'];
 
        $options = [
            'GROUP BY' => [ $fields['user_id'], $fields['user_name'] ],
            'ORDER BY' => 'timestamp DESC',
        ];
 
        $res = $dbr->select( $tables, $fields, $conds, __METHOD__, $options, $jconds );
        return new UserArrayFromResult( $res );
    }
 
    public function shouldCheckParserCache( ParserOptions $parserOptions, $oldId ) {
        return $parserOptions->getStubThreshold() == 0
            && $this->exists()
            && ( $oldId === null || $oldId === 0 || $oldId === $this->getLatest() )
            && $this->getContentHandler()->isParserCacheSupported();
    }
 
    public function getParserOutput(
        ParserOptions $parserOptions, $oldid = null, $forceParse = false
    ) {
        $useParserCache =
            ( !$forceParse ) && $this->shouldCheckParserCache( $parserOptions, $oldid );
 
        if ( $useParserCache && !$parserOptions->isSafeToCache() ) {
            throw new InvalidArgumentException(
                'The supplied ParserOptions are not safe to cache. Fix the options or set $forceParse = true.'
            );
        }
 
        wfDebug( __METHOD__ .
            ': using parser cache: ' . ( $useParserCache ? 'yes' : 'no' ) . "\n" );
        if ( $parserOptions->getStubThreshold() ) {
            wfIncrStats( 'pcache.miss.stub' );
        }
 
        if ( $useParserCache ) {
            $parserOutput = $this->getParserCache()
                ->get( $this, $parserOptions );
            if ( $parserOutput !== false ) {
                return $parserOutput;
            }
        }
 
        if ( $oldid === null || $oldid === 0 ) {
            $oldid = $this->getLatest();
        }
 
        $pool = new PoolWorkArticleView( $this, $parserOptions, $oldid, $useParserCache );
        $pool->execute();
 
        return $pool->getParserOutput();
    }
 
    public function doViewUpdates( User $user, $oldid = 0 ) {
        if ( wfReadOnly() ) {
            return;
        }
 
        // Update newtalk / watchlist notification status;
        // Avoid outage if the master is not reachable by using a deferred updated
        DeferredUpdates::addCallableUpdate(
            function () use ( $user, $oldid ) {
                Hooks::run( 'PageViewUpdates', [ $this, $user ] );
 
                $user->clearNotification( $this->mTitle, $oldid );
            },
            DeferredUpdates::PRESEND
        );
    }
 
    public function doPurge() {
        // Avoid PHP 7.1 warning of passing $this by reference
        $wikiPage = $this;
 
        if ( !Hooks::run( 'ArticlePurge', [ &$wikiPage ] ) ) {
            return false;
        }
 
        $this->mTitle->invalidateCache();
 
        // Clear file cache
        HTMLFileCache::clearFileCache( $this->getTitle() );
        // Send purge after above page_touched update was committed
        DeferredUpdates::addUpdate(
            new CdnCacheUpdate( $this->mTitle->getCdnUrls() ),
            DeferredUpdates::PRESEND
        );
 
        if ( $this->mTitle->getNamespace() == NS_MEDIAWIKI ) {
            $messageCache = MessageCache::singleton();
            $messageCache->updateMessageOverride( $this->mTitle, $this->getContent() );
        }
 
        return true;
    }
 
    public function insertOn( $dbw, $pageId = null ) {
        $pageIdForInsert = $pageId ? [ 'page_id' => $pageId ] : [];
        $dbw->insert(
            'page',
            [
                'page_namespace'    => $this->mTitle->getNamespace(),
                'page_title'        => $this->mTitle->getDBkey(),
                'page_restrictions' => '',
                'page_is_redirect'  => 0, // Will set this shortly...
                'page_is_new'       => 1,
                'page_random'       => wfRandom(),
                'page_touched'      => $dbw->timestamp(),
                'page_latest'       => 0, // Fill this in shortly...
                'page_len'          => 0, // Fill this in shortly...
            ] + $pageIdForInsert,
            __METHOD__,
            'IGNORE'
        );
 
        if ( $dbw->affectedRows() > 0 ) {
            $newid = $pageId ? (int)$pageId : $dbw->insertId();
            $this->mId = $newid;
            $this->mTitle->resetArticleID( $newid );
 
            return $newid;
        } else {
            return false; // nothing changed
        }
    }
 
    public function updateRevisionOn( $dbw, $revision, $lastRevision = null,
        $lastRevIsRedirect = null
    ) {
        global $wgContentHandlerUseDB;
 
        // TODO: move into PageUpdater or PageStore
        // NOTE: when doing that, make sure cached fields get reset in doEditContent,
        // and in the compat stub!
 
        // Assertion to try to catch T92046
        if ( (int)$revision->getId() === 0 ) {
            throw new InvalidArgumentException(
                __METHOD__ . ': Revision has ID ' . var_export( $revision->getId(), 1 )
            );
        }
 
        $content = $revision->getContent();
        $len = $content ? $content->getSize() : 0;
        $rt = $content ? $content->getUltimateRedirectTarget() : null;
 
        $conditions = [ 'page_id' => $this->getId() ];
 
        if ( !is_null( $lastRevision ) ) {
            // An extra check against threads stepping on each other
            $conditions['page_latest'] = $lastRevision;
        }
 
        $revId = $revision->getId();
        Assert::parameter( $revId > 0, '$revision->getId()', 'must be > 0' );
 
        $row = [ /* SET */
            'page_latest'      => $revId,
            'page_touched'     => $dbw->timestamp( $revision->getTimestamp() ),
            'page_is_new'      => ( $lastRevision === 0 ) ? 1 : 0,
            'page_is_redirect' => $rt !== null ? 1 : 0,
            'page_len'         => $len,
        ];
 
        if ( $wgContentHandlerUseDB ) {
            $row['page_content_model'] = $revision->getContentModel();
        }
 
        $dbw->update( 'page',
            $row,
            $conditions,
            __METHOD__ );
 
        $result = $dbw->affectedRows() > 0;
        if ( $result ) {
            $this->updateRedirectOn( $dbw, $rt, $lastRevIsRedirect );
            $this->setLastEdit( $revision );
            $this->mLatest = $revision->getId();
            $this->mIsRedirect = (bool)$rt;
            // Update the LinkCache.
            $linkCache = MediaWikiServices::getInstance()->getLinkCache();
            $linkCache->addGoodLinkObj(
                $this->getId(),
                $this->mTitle,
                $len,
                $this->mIsRedirect,
                $this->mLatest,
                $revision->getContentModel()
            );
        }
 
        return $result;
    }
 
    public function updateRedirectOn( $dbw, $redirectTitle, $lastRevIsRedirect = null ) {
        // Always update redirects (target link might have changed)
        // Update/Insert if we don't know if the last revision was a redirect or not
        // Delete if changing from redirect to non-redirect
        $isRedirect = !is_null( $redirectTitle );
 
        if ( !$isRedirect && $lastRevIsRedirect === false ) {
            return true;
        }
 
        if ( $isRedirect ) {
            $this->insertRedirectEntry( $redirectTitle );
        } else {
            // This is not a redirect, remove row from redirect table
            $where = [ 'rd_from' => $this->getId() ];
            $dbw->delete( 'redirect', $where, __METHOD__ );
        }
 
        if ( $this->getTitle()->getNamespace() == NS_FILE ) {
            RepoGroup::singleton()->getLocalRepo()->invalidateImageRedirect( $this->getTitle() );
        }
 
        return ( $dbw->affectedRows() != 0 );
    }
 
    public function updateIfNewerOn( $dbw, $revision ) {
        $row = $dbw->selectRow(
            [ 'revision', 'page' ],
            [ 'rev_id', 'rev_timestamp', 'page_is_redirect' ],
            [
                'page_id' => $this->getId(),
                'page_latest=rev_id' ],
            __METHOD__ );
 
        if ( $row ) {
            if ( wfTimestamp( TS_MW, $row->rev_timestamp ) >= $revision->getTimestamp() ) {
                return false;
            }
            $prev = $row->rev_id;
            $lastRevIsRedirect = (bool)$row->page_is_redirect;
        } else {
            // No or missing previous revision; mark the page as new
            $prev = 0;
            $lastRevIsRedirect = null;
        }
 
        $ret = $this->updateRevisionOn( $dbw, $revision, $prev, $lastRevIsRedirect );
 
        return $ret;
    }
 
    public static function hasDifferencesOutsideMainSlot( Revision $a, Revision $b ) {
        $aSlots = $a->getRevisionRecord()->getSlots();
        $bSlots = $b->getRevisionRecord()->getSlots();
        $changedRoles = $aSlots->getRolesWithDifferentContent( $bSlots );
 
        return ( $changedRoles !== [ SlotRecord::MAIN ] && $changedRoles !== [] );
    }
 
    public function getUndoContent( Revision $undo, Revision $undoafter ) {
        // TODO: MCR: replace this with a method that returns a RevisionSlotsUpdate
 
        if ( self::hasDifferencesOutsideMainSlot( $undo, $undoafter ) ) {
            // Cannot yet undo edits that involve anything other the main slot.
            return false;
        }
 
        $handler = $undo->getContentHandler();
        return $handler->getUndoContent( $this->getRevision(), $undo, $undoafter );
    }
 
    public function supportsSections() {
        return $this->getContentHandler()->supportsSections();
    }
 
    public function replaceSectionContent(
        $sectionId, Content $sectionContent, $sectionTitle = '', $edittime = null
    ) {
        $baseRevId = null;
        if ( $edittime && $sectionId !== 'new' ) {
            $lb = $this->getDBLoadBalancer();
            $dbr = $lb->getConnection( DB_REPLICA );
            $rev = Revision::loadFromTimestamp( $dbr, $this->mTitle, $edittime );
            // Try the master if this thread may have just added it.
            // This could be abstracted into a Revision method, but we don't want
            // to encourage loading of revisions by timestamp.
            if ( !$rev
                && $lb->getServerCount() > 1
                && $lb->hasOrMadeRecentMasterChanges()
            ) {
                $dbw = $lb->getConnection( DB_MASTER );
                $rev = Revision::loadFromTimestamp( $dbw, $this->mTitle, $edittime );
            }
            if ( $rev ) {
                $baseRevId = $rev->getId();
            }
        }
 
        return $this->replaceSectionAtRev( $sectionId, $sectionContent, $sectionTitle, $baseRevId );
    }
 
    public function replaceSectionAtRev( $sectionId, Content $sectionContent,
        $sectionTitle = '', $baseRevId = null
    ) {
        if ( strval( $sectionId ) === '' ) {
            // Whole-page edit; let the whole text through
            $newContent = $sectionContent;
        } else {
            if ( !$this->supportsSections() ) {
                throw new MWException( "sections not supported for content model " .
                    $this->getContentHandler()->getModelID() );
            }
 
            // T32711: always use current version when adding a new section
            if ( is_null( $baseRevId ) || $sectionId === 'new' ) {
                $oldContent = $this->getContent();
            } else {
                $rev = Revision::newFromId( $baseRevId );
                if ( !$rev ) {
                    wfDebug( __METHOD__ . " asked for bogus section (page: " .
                        $this->getId() . "; section: $sectionId)\n" );
                    return null;
                }
 
                $oldContent = $rev->getContent();
            }
 
            if ( !$oldContent ) {
                wfDebug( __METHOD__ . ": no page text\n" );
                return null;
            }
 
            $newContent = $oldContent->replaceSection( $sectionId, $sectionContent, $sectionTitle );
        }
 
        return $newContent;
    }
 
    public function checkFlags( $flags ) {
        if ( !( $flags & EDIT_NEW ) && !( $flags & EDIT_UPDATE ) ) {
            if ( $this->exists() ) {
                $flags |= EDIT_UPDATE;
            } else {
                $flags |= EDIT_NEW;
            }
        }
 
        return $flags;
    }
 
    private function newDerivedDataUpdater() {
        global $wgRCWatchCategoryMembership, $wgArticleCountMethod;
 
        $derivedDataUpdater = new DerivedPageDataUpdater(
            $this, // NOTE: eventually, PageUpdater should not know about WikiPage
            $this->getRevisionStore(),
            $this->getRevisionRenderer(),
            $this->getParserCache(),
            JobQueueGroup::singleton(),
            MessageCache::singleton(),
            MediaWikiServices::getInstance()->getContentLanguage(),
            MediaWikiServices::getInstance()->getDBLoadBalancerFactory()
        );
 
        $derivedDataUpdater->setRcWatchCategoryMembership( $wgRCWatchCategoryMembership );
        $derivedDataUpdater->setArticleCountMethod( $wgArticleCountMethod );
 
        return $derivedDataUpdater;
    }
 
    private function getDerivedDataUpdater(
        User $forUser = null,
        RevisionRecord $forRevision = null,
        RevisionSlotsUpdate $forUpdate = null,
        $forEdit = false
    ) {
        if ( !$forRevision && !$forUpdate ) {
            // NOTE: can't re-use an existing derivedDataUpdater if we don't know what the caller is
            // going to use it with.
            $this->derivedDataUpdater = null;
        }
 
        if ( $this->derivedDataUpdater && !$this->derivedDataUpdater->isContentPrepared() ) {
            // NOTE: can't re-use an existing derivedDataUpdater if other code that has a reference
            // to it did not yet initialize it, because we don't know what data it will be
            // initialized with.
            $this->derivedDataUpdater = null;
        }
 
        // XXX: It would be nice to have an LRU cache instead of trying to re-use a single instance.
        // However, there is no good way to construct a cache key. We'd need to check against all
        // cached instances.
 
        if ( $this->derivedDataUpdater
            && !$this->derivedDataUpdater->isReusableFor(
                $forUser,
                $forRevision,
                $forUpdate,
                $forEdit ? $this->getLatest() : null
            )
        ) {
            $this->derivedDataUpdater = null;
        }
 
        if ( !$this->derivedDataUpdater ) {
            $this->derivedDataUpdater = $this->newDerivedDataUpdater();
        }
 
        return $this->derivedDataUpdater;
    }
 
    public function newPageUpdater( User $user, RevisionSlotsUpdate $forUpdate = null ) {
        global $wgAjaxEditStash, $wgUseAutomaticEditSummaries, $wgPageCreationLog;
 
        $pageUpdater = new PageUpdater(
            $user,
            $this, // NOTE: eventually, PageUpdater should not know about WikiPage
            $this->getDerivedDataUpdater( $user, null, $forUpdate, true ),
            $this->getDBLoadBalancer(),
            $this->getRevisionStore()
        );
 
        $pageUpdater->setUsePageCreationLog( $wgPageCreationLog );
        $pageUpdater->setAjaxEditStash( $wgAjaxEditStash );
        $pageUpdater->setUseAutomaticEditSummaries( $wgUseAutomaticEditSummaries );
 
        return $pageUpdater;
    }
 
    public function doEditContent(
        Content $content, $summary, $flags = 0, $originalRevId = false,
        User $user = null, $serialFormat = null, $tags = [], $undidRevId = 0
    ) {
        global $wgUser, $wgUseNPPatrol, $wgUseRCPatrol;
 
        if ( !( $summary instanceof CommentStoreComment ) ) {
            $summary = CommentStoreComment::newUnsavedComment( trim( $summary ) );
        }
 
        if ( !$user ) {
            $user = $wgUser;
        }
 
        // TODO: this check is here for backwards-compatibility with 1.31 behavior.
        // Checking the minoredit right should be done in the same place the 'bot' right is
        // checked for the EDIT_FORCE_BOT flag, which is currently in EditPage::attemptSave.
        if ( ( $flags & EDIT_MINOR ) && !$user->isAllowed( 'minoredit' ) ) {
            $flags = ( $flags & ~EDIT_MINOR );
        }
 
        $slotsUpdate = new RevisionSlotsUpdate();
        $slotsUpdate->modifyContent( SlotRecord::MAIN, $content );
 
        // NOTE: while doEditContent() executes, callbacks to getDerivedDataUpdater and
        // prepareContentForEdit will generally use the DerivedPageDataUpdater that is also
        // used by this PageUpdater. However, there is no guarantee for this.
        $updater = $this->newPageUpdater( $user, $slotsUpdate );
        $updater->setContent( SlotRecord::MAIN, $content );
        $updater->setOriginalRevisionId( $originalRevId );
        $updater->setUndidRevisionId( $undidRevId );
 
        $needsPatrol = $wgUseRCPatrol || ( $wgUseNPPatrol && !$this->exists() );
 
        // TODO: this logic should not be in the storage layer, it's here for compatibility
        // with 1.31 behavior. Applying the 'autopatrol' right should be done in the same
        // place the 'bot' right is handled, which is currently in EditPage::attemptSave.
        if ( $needsPatrol && $this->getTitle()->userCan( 'autopatrol', $user ) ) {
            $updater->setRcPatrolStatus( RecentChange::PRC_AUTOPATROLLED );
        }
 
        $updater->addTags( $tags );
 
        $revRec = $updater->saveRevision(
            $summary,
            $flags
        );
 
        // $revRec will be null if the edit failed, or if no new revision was created because
        // the content did not change.
        if ( $revRec ) {
            // update cached fields
            // TODO: this is currently redundant to what is done in updateRevisionOn.
            // But updateRevisionOn() should move into PageStore, and then this will be needed.
            $this->setLastEdit( new Revision( $revRec ) ); // TODO: use RevisionRecord
            $this->mLatest = $revRec->getId();
        }
 
        return $updater->getStatus();
    }
 
    public function makeParserOptions( $context ) {
        $options = ParserOptions::newCanonical( $context );
 
        if ( $this->getTitle()->isConversionTable() ) {
            // @todo ConversionTable should become a separate content model, so
            // we don't need special cases like this one.
            $options->disableContentConversion();
        }
 
        return $options;
    }
 
    public function prepareContentForEdit(
        Content $content,
        $revision = null,
        User $user = null,
        $serialFormat = null,
        $useCache = true
    ) {
        global $wgUser;
 
        if ( !$user ) {
            $user = $wgUser;
        }
 
        if ( !is_object( $revision ) ) {
            $revid = $revision;
            // This code path is deprecated, and nothing is known to
            // use it, so performance here shouldn't be a worry.
            if ( $revid !== null ) {
                wfDeprecated( __METHOD__ . ' with $revision = revision ID', '1.25' );
                $store = $this->getRevisionStore();
                $revision = $store->getRevisionById( $revid, Revision::READ_LATEST );
            } else {
                $revision = null;
            }
        } elseif ( $revision instanceof Revision ) {
            $revision = $revision->getRevisionRecord();
        }
 
        $slots = RevisionSlotsUpdate::newFromContent( [ SlotRecord::MAIN => $content ] );
        $updater = $this->getDerivedDataUpdater( $user, $revision, $slots );
 
        if ( !$updater->isUpdatePrepared() ) {
            $updater->prepareContent( $user, $slots, $useCache );
 
            if ( $revision ) {
                $updater->prepareUpdate(
                    $revision,
                    [
                        'causeAction' => 'prepare-edit',
                        'causeAgent' => $user->getName(),
                    ]
                );
            }
        }
 
        return $updater->getPreparedEdit();
    }
 
    public function doEditUpdates( Revision $revision, User $user, array $options = [] ) {
        $options += [
            'causeAction' => 'edit-page',
            'causeAgent' => $user->getName(),
        ];
 
        $revision = $revision->getRevisionRecord();
 
        $updater = $this->getDerivedDataUpdater( $user, $revision );
 
        $updater->prepareUpdate( $revision, $options );
 
        $updater->doUpdates();
    }
 
    public function updateParserCache( array $options = [] ) {
        $revision = $this->getRevisionRecord();
        if ( !$revision || !$revision->getId() ) {
            LoggerFactory::getInstance( 'wikipage' )->info(
                __METHOD__ . 'called with ' . ( $revision ? 'unsaved' : 'no' ) . ' revision'
            );
            return;
        }
        $user = User::newFromIdentity( $revision->getUser( RevisionRecord::RAW ) );
 
        $updater = $this->getDerivedDataUpdater( $user, $revision );
        $updater->prepareUpdate( $revision, $options );
        $updater->doParserCacheUpdate();
    }
 
    public function doSecondaryDataUpdates( array $options = [] ) {
        $options['recursive'] = $options['recursive'] ?? true;
        $revision = $this->getRevisionRecord();
        if ( !$revision || !$revision->getId() ) {
            LoggerFactory::getInstance( 'wikipage' )->info(
                __METHOD__ . 'called with ' . ( $revision ? 'unsaved' : 'no' ) . ' revision'
            );
            return;
        }
        $user = User::newFromIdentity( $revision->getUser( RevisionRecord::RAW ) );
 
        $updater = $this->getDerivedDataUpdater( $user, $revision );
        $updater->prepareUpdate( $revision, $options );
        $updater->doSecondaryDataUpdates( $options );
    }
 
    public function doUpdateRestrictions( array $limit, array $expiry,
        &$cascade, $reason, User $user, $tags = null
    ) {
        global $wgCascadingRestrictionLevels;
 
        if ( wfReadOnly() ) {
            return Status::newFatal( wfMessage( 'readonlytext', wfReadOnlyReason() ) );
        }
 
        $this->loadPageData( 'fromdbmaster' );
        $restrictionTypes = $this->mTitle->getRestrictionTypes();
        $id = $this->getId();
 
        if ( !$cascade ) {
            $cascade = false;
        }
 
        // Take this opportunity to purge out expired restrictions
        Title::purgeExpiredRestrictions();
 
        // @todo: Same limitations as described in ProtectionForm.php (line 37);
        // we expect a single selection, but the schema allows otherwise.
        $isProtected = false;
        $protect = false;
        $changed = false;
 
        $dbw = wfGetDB( DB_MASTER );
 
        foreach ( $restrictionTypes as $action ) {
            if ( !isset( $expiry[$action] ) || $expiry[$action] === $dbw->getInfinity() ) {
                $expiry[$action] = 'infinity';
            }
            if ( !isset( $limit[$action] ) ) {
                $limit[$action] = '';
            } elseif ( $limit[$action] != '' ) {
                $protect = true;
            }
 
            // Get current restrictions on $action
            $current = implode( '', $this->mTitle->getRestrictions( $action ) );
            if ( $current != '' ) {
                $isProtected = true;
            }
 
            if ( $limit[$action] != $current ) {
                $changed = true;
            } elseif ( $limit[$action] != '' ) {
                // Only check expiry change if the action is actually being
                // protected, since expiry does nothing on an not-protected
                // action.
                if ( $this->mTitle->getRestrictionExpiry( $action ) != $expiry[$action] ) {
                    $changed = true;
                }
            }
        }
 
        if ( !$changed && $protect && $this->mTitle->areRestrictionsCascading() != $cascade ) {
            $changed = true;
        }
 
        // If nothing has changed, do nothing
        if ( !$changed ) {
            return Status::newGood();
        }
 
        if ( !$protect ) { // No protection at all means unprotection
            $revCommentMsg = 'unprotectedarticle-comment';
            $logAction = 'unprotect';
        } elseif ( $isProtected ) {
            $revCommentMsg = 'modifiedarticleprotection-comment';
            $logAction = 'modify';
        } else {
            $revCommentMsg = 'protectedarticle-comment';
            $logAction = 'protect';
        }
 
        $logRelationsValues = [];
        $logRelationsField = null;
        $logParamsDetails = [];
 
        // Null revision (used for change tag insertion)
        $nullRevision = null;
 
        if ( $id ) { // Protection of existing page
            // Avoid PHP 7.1 warning of passing $this by reference
            $wikiPage = $this;
 
            if ( !Hooks::run( 'ArticleProtect', [ &$wikiPage, &$user, $limit, $reason ] ) ) {
                return Status::newGood();
            }
 
            // Only certain restrictions can cascade...
            $editrestriction = isset( $limit['edit'] )
                ? [ $limit['edit'] ]
                : $this->mTitle->getRestrictions( 'edit' );
            foreach ( array_keys( $editrestriction, 'sysop' ) as $key ) {
                $editrestriction[$key] = 'editprotected'; // backwards compatibility
            }
            foreach ( array_keys( $editrestriction, 'autoconfirmed' ) as $key ) {
                $editrestriction[$key] = 'editsemiprotected'; // backwards compatibility
            }
 
            $cascadingRestrictionLevels = $wgCascadingRestrictionLevels;
            foreach ( array_keys( $cascadingRestrictionLevels, 'sysop' ) as $key ) {
                $cascadingRestrictionLevels[$key] = 'editprotected'; // backwards compatibility
            }
            foreach ( array_keys( $cascadingRestrictionLevels, 'autoconfirmed' ) as $key ) {
                $cascadingRestrictionLevels[$key] = 'editsemiprotected'; // backwards compatibility
            }
 
            // The schema allows multiple restrictions
            if ( !array_intersect( $editrestriction, $cascadingRestrictionLevels ) ) {
                $cascade = false;
            }
 
            // insert null revision to identify the page protection change as edit summary
            $latest = $this->getLatest();
            $nullRevision = $this->insertProtectNullRevision(
                $revCommentMsg,
                $limit,
                $expiry,
                $cascade,
                $reason,
                $user
            );
 
            if ( $nullRevision === null ) {
                return Status::newFatal( 'no-null-revision', $this->mTitle->getPrefixedText() );
            }
 
            $logRelationsField = 'pr_id';
 
            // Update restrictions table
            foreach ( $limit as $action => $restrictions ) {
                $dbw->delete(
                    'page_restrictions',
                    [
                        'pr_page' => $id,
                        'pr_type' => $action
                    ],
                    __METHOD__
                );
                if ( $restrictions != '' ) {
                    $cascadeValue = ( $cascade && $action == 'edit' ) ? 1 : 0;
                    $dbw->insert(
                        'page_restrictions',
                        [
                            'pr_page' => $id,
                            'pr_type' => $action,
                            'pr_level' => $restrictions,
                            'pr_cascade' => $cascadeValue,
                            'pr_expiry' => $dbw->encodeExpiry( $expiry[$action] )
                        ],
                        __METHOD__
                    );
                    $logRelationsValues[] = $dbw->insertId();
                    $logParamsDetails[] = [
                        'type' => $action,
                        'level' => $restrictions,
                        'expiry' => $expiry[$action],
                        'cascade' => (bool)$cascadeValue,
                    ];
                }
            }
 
            // Clear out legacy restriction fields
            $dbw->update(
                'page',
                [ 'page_restrictions' => '' ],
                [ 'page_id' => $id ],
                __METHOD__
            );
 
            // Avoid PHP 7.1 warning of passing $this by reference
            $wikiPage = $this;
 
            Hooks::run( 'NewRevisionFromEditComplete',
                [ $this, $nullRevision, $latest, $user ] );
            Hooks::run( 'ArticleProtectComplete', [ &$wikiPage, &$user, $limit, $reason ] );
        } else { // Protection of non-existing page (also known as "title protection")
            // Cascade protection is meaningless in this case
            $cascade = false;
 
            if ( $limit['create'] != '' ) {
                $commentFields = CommentStore::getStore()->insert( $dbw, 'pt_reason', $reason );
                $dbw->replace( 'protected_titles',
                    [ [ 'pt_namespace', 'pt_title' ] ],
                    [
                        'pt_namespace' => $this->mTitle->getNamespace(),
                        'pt_title' => $this->mTitle->getDBkey(),
                        'pt_create_perm' => $limit['create'],
                        'pt_timestamp' => $dbw->timestamp(),
                        'pt_expiry' => $dbw->encodeExpiry( $expiry['create'] ),
                        'pt_user' => $user->getId(),
                    ] + $commentFields, __METHOD__
                );
                $logParamsDetails[] = [
                    'type' => 'create',
                    'level' => $limit['create'],
                    'expiry' => $expiry['create'],
                ];
            } else {
                $dbw->delete( 'protected_titles',
                    [
                        'pt_namespace' => $this->mTitle->getNamespace(),
                        'pt_title' => $this->mTitle->getDBkey()
                    ], __METHOD__
                );
            }
        }
 
        $this->mTitle->flushRestrictions();
        InfoAction::invalidateCache( $this->mTitle );
 
        if ( $logAction == 'unprotect' ) {
            $params = [];
        } else {
            $protectDescriptionLog = $this->protectDescriptionLog( $limit, $expiry );
            $params = [
                '4::description' => $protectDescriptionLog, // parameter for IRC
                '5:bool:cascade' => $cascade,
                'details' => $logParamsDetails, // parameter for localize and api
            ];
        }
 
        // Update the protection log
        $logEntry = new ManualLogEntry( 'protect', $logAction );
        $logEntry->setTarget( $this->mTitle );
        $logEntry->setComment( $reason );
        $logEntry->setPerformer( $user );
        $logEntry->setParameters( $params );
        if ( !is_null( $nullRevision ) ) {
            $logEntry->setAssociatedRevId( $nullRevision->getId() );
        }
        $logEntry->setTags( $tags );
        if ( $logRelationsField !== null && count( $logRelationsValues ) ) {
            $logEntry->setRelations( [ $logRelationsField => $logRelationsValues ] );
        }
        $logId = $logEntry->insert();
        $logEntry->publish( $logId );
 
        return Status::newGood( $logId );
    }
 
    public function insertProtectNullRevision( $revCommentMsg, array $limit,
        array $expiry, $cascade, $reason, $user = null
    ) {
        $dbw = wfGetDB( DB_MASTER );
 
        // Prepare a null revision to be added to the history
        $editComment = wfMessage(
            $revCommentMsg,
            $this->mTitle->getPrefixedText(),
            $user ? $user->getName() : ''
        )->inContentLanguage()->text();
        if ( $reason ) {
            $editComment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
        }
        $protectDescription = $this->protectDescription( $limit, $expiry );
        if ( $protectDescription ) {
            $editComment .= wfMessage( 'word-separator' )->inContentLanguage()->text();
            $editComment .= wfMessage( 'parentheses' )->params( $protectDescription )
                ->inContentLanguage()->text();
        }
        if ( $cascade ) {
            $editComment .= wfMessage( 'word-separator' )->inContentLanguage()->text();
            $editComment .= wfMessage( 'brackets' )->params(
                wfMessage( 'protect-summary-cascade' )->inContentLanguage()->text()
            )->inContentLanguage()->text();
        }
 
        $nullRev = Revision::newNullRevision( $dbw, $this->getId(), $editComment, true, $user );
        if ( $nullRev ) {
            $nullRev->insertOn( $dbw );
 
            // Update page record and touch page
            $oldLatest = $nullRev->getParentId();
            $this->updateRevisionOn( $dbw, $nullRev, $oldLatest );
        }
 
        return $nullRev;
    }
 
    protected function formatExpiry( $expiry ) {
        if ( $expiry != 'infinity' ) {
            $contLang = MediaWikiServices::getInstance()->getContentLanguage();
            return wfMessage(
                'protect-expiring',
                $contLang->timeanddate( $expiry, false, false ),
                $contLang->date( $expiry, false, false ),
                $contLang->time( $expiry, false, false )
            )->inContentLanguage()->text();
        } else {
            return wfMessage( 'protect-expiry-indefinite' )
                ->inContentLanguage()->text();
        }
    }
 
    public function protectDescription( array $limit, array $expiry ) {
        $protectDescription = '';
 
        foreach ( array_filter( $limit ) as $action => $restrictions ) {
            # $action is one of $wgRestrictionTypes = [ 'create', 'edit', 'move', 'upload' ].
            # All possible message keys are listed here for easier grepping:
            # * restriction-create
            # * restriction-edit
            # * restriction-move
            # * restriction-upload
            $actionText = wfMessage( 'restriction-' . $action )->inContentLanguage()->text();
            # $restrictions is one of $wgRestrictionLevels = [ '', 'autoconfirmed', 'sysop' ],
            # with '' filtered out. All possible message keys are listed below:
            # * protect-level-autoconfirmed
            # * protect-level-sysop
            $restrictionsText = wfMessage( 'protect-level-' . $restrictions )
                ->inContentLanguage()->text();
 
            $expiryText = $this->formatExpiry( $expiry[$action] );
 
            if ( $protectDescription !== '' ) {
                $protectDescription .= wfMessage( 'word-separator' )->inContentLanguage()->text();
            }
            $protectDescription .= wfMessage( 'protect-summary-desc' )
                ->params( $actionText, $restrictionsText, $expiryText )
                ->inContentLanguage()->text();
        }
 
        return $protectDescription;
    }
 
    public function protectDescriptionLog( array $limit, array $expiry ) {
        $protectDescriptionLog = '';
 
        $dirMark = MediaWikiServices::getInstance()->getContentLanguage()->getDirMark();
        foreach ( array_filter( $limit ) as $action => $restrictions ) {
            $expiryText = $this->formatExpiry( $expiry[$action] );
            $protectDescriptionLog .=
                $dirMark .
                "[$action=$restrictions] ($expiryText)";
        }
 
        return trim( $protectDescriptionLog );
    }
 
    protected static function flattenRestrictions( $limit ) {
        if ( !is_array( $limit ) ) {
            throw new MWException( __METHOD__ . ' given non-array restriction set' );
        }
 
        $bits = [];
        ksort( $limit );
 
        foreach ( array_filter( $limit ) as $action => $restrictions ) {
            $bits[] = "$action=$restrictions";
        }
 
        return implode( ':', $bits );
    }
 
    public function isBatchedDelete( $safetyMargin = 0 ) {
        global $wgDeleteRevisionsBatchSize;
 
        $dbr = wfGetDB( DB_REPLICA );
        $revCount = $this->getRevisionStore()->countRevisionsByPageId( $dbr, $this->getId() );
        $revCount += $safetyMargin;
 
        return $revCount >= $wgDeleteRevisionsBatchSize;
    }
 
    public function doDeleteArticle(
        $reason, $suppress = false, $u1 = null, $u2 = null, &$error = '', User $user = null,
        $immediate = false
    ) {
        $status = $this->doDeleteArticleReal( $reason, $suppress, $u1, $u2, $error, $user,
            [], 'delete', $immediate );
 
        // Returns true if the page was actually deleted, or is scheduled for deletion
        return $status->isOK();
    }
 
    public function doDeleteArticleReal(
        $reason, $suppress = false, $u1 = null, $u2 = null, &$error = '', User $deleter = null,
        $tags = [], $logsubtype = 'delete', $immediate = false
    ) {
        global $wgUser;
 
        wfDebug( __METHOD__ . "\n" );
 
        $status = Status::newGood();
 
        // Avoid PHP 7.1 warning of passing $this by reference
        $wikiPage = $this;
 
        $deleter = is_null( $deleter ) ? $wgUser : $deleter;
        if ( !Hooks::run( 'ArticleDelete',
            [ &$wikiPage, &$deleter, &$reason, &$error, &$status, $suppress ]
        ) ) {
            if ( $status->isOK() ) {
                // Hook aborted but didn't set a fatal status
                $status->fatal( 'delete-hook-aborted' );
            }
            return $status;
        }
 
        return $this->doDeleteArticleBatched( $reason, $suppress, $deleter, $tags,
            $logsubtype, $immediate );
    }
 
    public function doDeleteArticleBatched(
        $reason, $suppress, User $deleter, $tags,
        $logsubtype, $immediate = false, $webRequestId = null
    ) {
        wfDebug( __METHOD__ . "\n" );
 
        $status = Status::newGood();
 
        $dbw = wfGetDB( DB_MASTER );
        $dbw->startAtomic( __METHOD__ );
 
        $this->loadPageData( self::READ_LATEST );
        $id = $this->getId();
        // T98706: lock the page from various other updates but avoid using
        // WikiPage::READ_LOCKING as that will carry over the FOR UPDATE to
        // the revisions queries (which also JOIN on user). Only lock the page
        // row and CAS check on page_latest to see if the trx snapshot matches.
        $lockedLatest = $this->lockAndGetLatest();
        if ( $id == 0 || $this->getLatest() != $lockedLatest ) {
            $dbw->endAtomic( __METHOD__ );
            // Page not there or trx snapshot is stale
            $status->error( 'cannotdelete',
                wfEscapeWikiText( $this->getTitle()->getPrefixedText() ) );
            return $status;
        }
 
        // At this point we are now committed to returning an OK
        // status unless some DB query error or other exception comes up.
        // This way callers don't have to call rollback() if $status is bad
        // unless they actually try to catch exceptions (which is rare).
 
        // we need to remember the old content so we can use it to generate all deletion updates.
        $revision = $this->getRevision();
        try {
            $content = $this->getContent( Revision::RAW );
        } catch ( Exception $ex ) {
            wfLogWarning( __METHOD__ . ': failed to load content during deletion! '
                . $ex->getMessage() );
 
            $content = null;
        }
 
        // Archive revisions.  In immediate mode, archive all revisions.  Otherwise, archive
        // one batch of revisions and defer archival of any others to the job queue.
        $explictTrxLogged = false;
        while ( true ) {
            $done = $this->archiveRevisions( $dbw, $id, $suppress );
            if ( $done || !$immediate ) {
                break;
            }
            $dbw->endAtomic( __METHOD__ );
            if ( $dbw->explicitTrxActive() ) {
                // Explict transactions may never happen here in practice.  Log to be sure.
                if ( !$explictTrxLogged ) {
                    $explictTrxLogged = true;
                    LoggerFactory::getInstance( 'wfDebug' )->debug(
                        'explicit transaction active in ' . __METHOD__ . ' while deleting {title}', [
                        'title' => $this->getTitle()->getText(),
                    ] );
                }
                continue;
            }
            if ( $dbw->trxLevel() ) {
                $dbw->commit();
            }
            $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
            $lbFactory->waitForReplication();
            $dbw->startAtomic( __METHOD__ );
        }
 
        // If done archiving, also delete the article.
        if ( !$done ) {
            $dbw->endAtomic( __METHOD__ );
 
            $jobParams = [
                'wikiPageId' => $id,
                'requestId' => $webRequestId ?? WebRequest::getRequestId(),
                'reason' => $reason,
                'suppress' => $suppress,
                'userId' => $deleter->getId(),
                'tags' => json_encode( $tags ),
                'logsubtype' => $logsubtype,
            ];
 
            $job = new DeletePageJob( $this->getTitle(), $jobParams );
            JobQueueGroup::singleton()->push( $job );
 
            $status->warning( 'delete-scheduled',
                wfEscapeWikiText( $this->getTitle()->getPrefixedText() ) );
        } else {
            // Get archivedRevisionCount by db query, because there's no better alternative.
            // Jobs cannot pass a count of archived revisions to the next job, because additional
            // deletion operations can be started while the first is running.  Jobs from each
            // gracefully interleave, but would not know about each other's count.  Deduplication
            // in the job queue to avoid simultaneous deletion operations would add overhead.
            // Number of archived revisions cannot be known beforehand, because edits can be made
            // while deletion operations are being processed, changing the number of archivals.
            $archivedRevisionCount = $dbw->selectField(
                'archive', 'COUNT(*)',
                [
                    'ar_namespace' => $this->getTitle()->getNamespace(),
                    'ar_title' => $this->getTitle()->getDBkey(),
                    'ar_page_id' => $id
                ], __METHOD__
            );
 
            // Clone the title and wikiPage, so we have the information we need when
            // we log and run the ArticleDeleteComplete hook.
            $logTitle = clone $this->mTitle;
            $wikiPageBeforeDelete = clone $this;
 
            // Now that it's safely backed up, delete it
            $dbw->delete( 'page', [ 'page_id' => $id ], __METHOD__ );
 
            // Log the deletion, if the page was suppressed, put it in the suppression log instead
            $logtype = $suppress ? 'suppress' : 'delete';
 
            $logEntry = new ManualLogEntry( $logtype, $logsubtype );
            $logEntry->setPerformer( $deleter );
            $logEntry->setTarget( $logTitle );
            $logEntry->setComment( $reason );
            $logEntry->setTags( $tags );
            $logid = $logEntry->insert();
 
            $dbw->onTransactionPreCommitOrIdle(
                function () use ( $logEntry, $logid ) {
                    // T58776: avoid deadlocks (especially from FileDeleteForm)
                    $logEntry->publish( $logid );
                },
                __METHOD__
            );
 
            $dbw->endAtomic( __METHOD__ );
 
            $this->doDeleteUpdates( $id, $content, $revision, $deleter );
 
            Hooks::run( 'ArticleDeleteComplete', [
                &$wikiPageBeforeDelete,
                &$deleter,
                $reason,
                $id,
                $content,
                $logEntry,
                $archivedRevisionCount
            ] );
            $status->value = $logid;
 
            // Show log excerpt on 404 pages rather than just a link
            $cache = MediaWikiServices::getInstance()->getMainObjectStash();
            $key = $cache->makeKey( 'page-recent-delete', md5( $logTitle->getPrefixedText() ) );
            $cache->set( $key, 1, $cache::TTL_DAY );
        }
 
        return $status;
    }
 
    protected function archiveRevisions( $dbw, $id, $suppress ) {
        global $wgContentHandlerUseDB, $wgMultiContentRevisionSchemaMigrationStage,
            $wgCommentTableSchemaMigrationStage, $wgActorTableSchemaMigrationStage,
            $wgDeleteRevisionsBatchSize;
 
        // Given the lock above, we can be confident in the title and page ID values
        $namespace = $this->getTitle()->getNamespace();
        $dbKey = $this->getTitle()->getDBkey();
 
        $commentStore = CommentStore::getStore();
        $actorMigration = ActorMigration::newMigration();
 
        $revQuery = Revision::getQueryInfo();
        $bitfield = false;
 
        // Bitfields to further suppress the content
        if ( $suppress ) {
            $bitfield = Revision::SUPPRESSED_ALL;
            $revQuery['fields'] = array_diff( $revQuery['fields'], [ 'rev_deleted' ] );
        }
 
        // For now, shunt the revision data into the archive table.
        // Text is *not* removed from the text table; bulk storage
        // is left intact to avoid breaking block-compression or
        // immutable storage schemes.
        // In the future, we may keep revisions and mark them with
        // the rev_deleted field, which is reserved for this purpose.
 
        // Lock rows in `revision` and its temp tables, but not any others.
        // Note array_intersect() preserves keys from the first arg, and we're
        // assuming $revQuery has `revision` primary and isn't using subtables
        // for anything we care about.
        $dbw->lockForUpdate(
            array_intersect(
                $revQuery['tables'],
                [ 'revision', 'revision_comment_temp', 'revision_actor_temp' ]
            ),
            [ 'rev_page' => $id ],
            __METHOD__,
            [],
            $revQuery['joins']
        );
 
        // If SCHEMA_COMPAT_WRITE_OLD is set, also select all extra fields we still write,
        // so we can copy it to the archive table.
        // We know the fields exist, otherwise SCHEMA_COMPAT_WRITE_OLD could not function.
        if ( $wgMultiContentRevisionSchemaMigrationStage & SCHEMA_COMPAT_WRITE_OLD ) {
            $revQuery['fields'][] = 'rev_text_id';
 
            if ( $wgContentHandlerUseDB ) {
                $revQuery['fields'][] = 'rev_content_model';
                $revQuery['fields'][] = 'rev_content_format';
            }
        }
 
        // Get as many of the page revisions as we are allowed to.  The +1 lets us recognize the
        // unusual case where there were exactly $wgDeleteRevisionBatchSize revisions remaining.
        $res = $dbw->select(
            $revQuery['tables'],
            $revQuery['fields'],
            [ 'rev_page' => $id ],
            __METHOD__,
            [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => $wgDeleteRevisionsBatchSize + 1 ],
            $revQuery['joins']
        );
 
        // Build their equivalent archive rows
        $rowsInsert = [];
        $revids = [];
 
        $ipRevIds = [];
 
        $done = true;
        foreach ( $res as $row ) {
            if ( count( $revids ) >= $wgDeleteRevisionsBatchSize ) {
                $done = false;
                break;
            }
 
            $comment = $commentStore->getComment( 'rev_comment', $row );
            $user = User::newFromAnyId( $row->rev_user, $row->rev_user_text, $row->rev_actor );
            $rowInsert = [
                    'ar_namespace'  => $namespace,
                    'ar_title'      => $dbKey,
                    'ar_timestamp'  => $row->rev_timestamp,
                    'ar_minor_edit' => $row->rev_minor_edit,
                    'ar_rev_id'     => $row->rev_id,
                    'ar_parent_id'  => $row->rev_parent_id,
                    'ar_len'        => $row->rev_len,
                    'ar_page_id'    => $id,
                    'ar_deleted'    => $suppress ? $bitfield : $row->rev_deleted,
                    'ar_sha1'       => $row->rev_sha1,
                ] + $commentStore->insert( $dbw, 'ar_comment', $comment )
                + $actorMigration->getInsertValues( $dbw, 'ar_user', $user );
 
            if ( $wgMultiContentRevisionSchemaMigrationStage & SCHEMA_COMPAT_WRITE_OLD ) {
                $rowInsert['ar_text_id'] = $row->rev_text_id;
 
                if ( $wgContentHandlerUseDB ) {
                    $rowInsert['ar_content_model'] = $row->rev_content_model;
                    $rowInsert['ar_content_format'] = $row->rev_content_format;
                }
            }
 
            $rowsInsert[] = $rowInsert;
            $revids[] = $row->rev_id;
 
            // Keep track of IP edits, so that the corresponding rows can
            // be deleted in the ip_changes table.
            if ( (int)$row->rev_user === 0 && IP::isValid( $row->rev_user_text ) ) {
                $ipRevIds[] = $row->rev_id;
            }
        }
 
        // This conditional is just a sanity check
        if ( count( $revids ) > 0 ) {
            // Copy them into the archive table
            $dbw->insert( 'archive', $rowsInsert, __METHOD__ );
 
            $dbw->delete( 'revision', [ 'rev_id' => $revids ], __METHOD__ );
            if ( $wgCommentTableSchemaMigrationStage > MIGRATION_OLD ) {
                $dbw->delete( 'revision_comment_temp', [ 'revcomment_rev' => $revids ], __METHOD__ );
            }
            if ( $wgActorTableSchemaMigrationStage & SCHEMA_COMPAT_WRITE_NEW ) {
                $dbw->delete( 'revision_actor_temp', [ 'revactor_rev' => $revids ], __METHOD__ );
            }
 
            // Also delete records from ip_changes as applicable.
            if ( count( $ipRevIds ) > 0 ) {
                $dbw->delete( 'ip_changes', [ 'ipc_rev_id' => $ipRevIds ], __METHOD__ );
            }
        }
 
        return $done;
    }
 
    public function lockAndGetLatest() {
        return (int)wfGetDB( DB_MASTER )->selectField(
            'page',
            'page_latest',
            [
                'page_id' => $this->getId(),
                // Typically page_id is enough, but some code might try to do
                // updates assuming the title is the same, so verify that
                'page_namespace' => $this->getTitle()->getNamespace(),
                'page_title' => $this->getTitle()->getDBkey()
            ],
            __METHOD__,
            [ 'FOR UPDATE' ]
        );
    }
 
    public function doDeleteUpdates(
        $id, Content $content = null, Revision $revision = null, User $user = null
    ) {
        if ( $id !== $this->getId() ) {
            throw new InvalidArgumentException( 'Mismatching page ID' );
        }
 
        try {
            $countable = $this->isCountable();
        } catch ( Exception $ex ) {
            // fallback for deleting broken pages for which we cannot load the content for
            // some reason. Note that doDeleteArticleReal() already logged this problem.
            $countable = false;
        }
 
        // Update site status
        DeferredUpdates::addUpdate( SiteStatsUpdate::factory(
            [ 'edits' => 1, 'articles' => -$countable, 'pages' => -1 ]
        ) );
 
        // Delete pagelinks, update secondary indexes, etc
        $updates = $this->getDeletionUpdates(
            $revision ? $revision->getRevisionRecord() : $content
        );
        foreach ( $updates as $update ) {
            DeferredUpdates::addUpdate( $update );
        }
 
        $causeAgent = $user ? $user->getName() : 'unknown';
        // Reparse any pages transcluding this page
        LinksUpdate::queueRecursiveJobsForTable(
            $this->mTitle, 'templatelinks', 'delete-page', $causeAgent );
        // Reparse any pages including this image
        if ( $this->mTitle->getNamespace() == NS_FILE ) {
            LinksUpdate::queueRecursiveJobsForTable(
                $this->mTitle, 'imagelinks', 'delete-page', $causeAgent );
        }
 
        // Clear caches
        self::onArticleDelete( $this->mTitle );
        ResourceLoaderWikiModule::invalidateModuleCache(
            $this->mTitle, $revision, null, wfWikiID()
        );
 
        // Reset this object and the Title object
        $this->loadFromRow( false, self::READ_LATEST );
 
        // Search engine
        DeferredUpdates::addUpdate( new SearchUpdate( $id, $this->mTitle ) );
    }
 
    public function doRollback(
        $fromP, $summary, $token, $bot, &$resultDetails, User $user, $tags = null
    ) {
        $resultDetails = null;
 
        // Check permissions
        $editErrors = $this->mTitle->getUserPermissionsErrors( 'edit', $user );
        $rollbackErrors = $this->mTitle->getUserPermissionsErrors( 'rollback', $user );
        $errors = array_merge( $editErrors, wfArrayDiff2( $rollbackErrors, $editErrors ) );
 
        if ( !$user->matchEditToken( $token, 'rollback' ) ) {
            $errors[] = [ 'sessionfailure' ];
        }
 
        if ( $user->pingLimiter( 'rollback' ) || $user->pingLimiter() ) {
            $errors[] = [ 'actionthrottledtext' ];
        }
 
        // If there were errors, bail out now
        if ( !empty( $errors ) ) {
            return $errors;
        }
 
        return $this->commitRollback( $fromP, $summary, $bot, $resultDetails, $user, $tags );
    }
 
    public function commitRollback( $fromP, $summary, $bot,
        &$resultDetails, User $guser, $tags = null
    ) {
        global $wgUseRCPatrol;
 
        $dbw = wfGetDB( DB_MASTER );
 
        if ( wfReadOnly() ) {
            return [ [ 'readonlytext' ] ];
        }
 
        // Begin revision creation cycle by creating a PageUpdater.
        // If the page is changed concurrently after grabParentRevision(), the rollback will fail.
        $updater = $this->newPageUpdater( $guser );
        $current = $updater->grabParentRevision();
 
        if ( is_null( $current ) ) {
            // Something wrong... no page?
            return [ [ 'notanarticle' ] ];
        }
 
        $currentEditorForPublic = $current->getUser( RevisionRecord::FOR_PUBLIC );
        $legacyCurrent = new Revision( $current );
        $from = str_replace( '_', ' ', $fromP );
 
        // User name given should match up with the top revision.
        // If the revision's user is not visible, then $from should be empty.
        if ( $from !== ( $currentEditorForPublic ? $currentEditorForPublic->getName() : '' ) ) {
            $resultDetails = [ 'current' => $legacyCurrent ];
            return [ [ 'alreadyrolled',
                htmlspecialchars( $this->mTitle->getPrefixedText() ),
                htmlspecialchars( $fromP ),
                htmlspecialchars( $currentEditorForPublic ? $currentEditorForPublic->getName() : '' )
            ] ];
        }
 
        // Get the last edit not by this person...
        // Note: these may not be public values
        $actorWhere = ActorMigration::newMigration()->getWhere(
            $dbw,
            'rev_user',
            $current->getUser( RevisionRecord::RAW )
        );
 
        $s = $dbw->selectRow(
            [ 'revision' ] + $actorWhere['tables'],
            [ 'rev_id', 'rev_timestamp', 'rev_deleted' ],
            [
                'rev_page' => $current->getPageId(),
                'NOT(' . $actorWhere['conds'] . ')',
            ],
            __METHOD__,
            [
                'USE INDEX' => [ 'revision' => 'page_timestamp' ],
                'ORDER BY' => 'rev_timestamp DESC'
            ],
            $actorWhere['joins']
        );
        if ( $s === false ) {
            // No one else ever edited this page
            return [ [ 'cantrollback' ] ];
        } elseif ( $s->rev_deleted & RevisionRecord::DELETED_TEXT
            || $s->rev_deleted & RevisionRecord::DELETED_USER
        ) {
            // Only admins can see this text
            return [ [ 'notvisiblerev' ] ];
        }
 
        // Generate the edit summary if necessary
        $target = $this->getRevisionStore()->getRevisionById(
            $s->rev_id,
            RevisionStore::READ_LATEST
        );
        if ( empty( $summary ) ) {
            if ( !$currentEditorForPublic ) { // no public user name
                $summary = wfMessage( 'revertpage-nouser' );
            } else {
                $summary = wfMessage( 'revertpage' );
            }
        }
        $legacyTarget = new Revision( $target );
        $targetEditorForPublic = $target->getUser( RevisionRecord::FOR_PUBLIC );
 
        // Allow the custom summary to use the same args as the default message
        $contLang = MediaWikiServices::getInstance()->getContentLanguage();
        $args = [
            $targetEditorForPublic ? $targetEditorForPublic->getName() : null,
            $currentEditorForPublic ? $currentEditorForPublic->getName() : null,
            $s->rev_id,
            $contLang->timeanddate( wfTimestamp( TS_MW, $s->rev_timestamp ) ),
            $current->getId(),
            $contLang->timeanddate( $current->getTimestamp() )
        ];
        if ( $summary instanceof Message ) {
            $summary = $summary->params( $args )->inContentLanguage()->text();
        } else {
            $summary = wfMsgReplaceArgs( $summary, $args );
        }
 
        // Trim spaces on user supplied text
        $summary = trim( $summary );
 
        // Save
        $flags = EDIT_UPDATE | EDIT_INTERNAL;
 
        if ( $guser->isAllowed( 'minoredit' ) ) {
            $flags |= EDIT_MINOR;
        }
 
        if ( $bot && ( $guser->isAllowedAny( 'markbotedits', 'bot' ) ) ) {
            $flags |= EDIT_FORCE_BOT;
        }
 
        // TODO: MCR: also log model changes in other slots, in case that becomes possible!
        $currentContent = $current->getContent( SlotRecord::MAIN );
        $targetContent = $target->getContent( SlotRecord::MAIN );
        $changingContentModel = $targetContent->getModel() !== $currentContent->getModel();
 
        if ( in_array( 'mw-rollback', ChangeTags::getSoftwareTags() ) ) {
            $tags[] = 'mw-rollback';
        }
 
        // Build rollback revision:
        // Restore old content
        // TODO: MCR: test this once we can store multiple slots
        foreach ( $target->getSlots()->getSlots() as $slot ) {
            $updater->inheritSlot( $slot );
        }
 
        // Remove extra slots
        // TODO: MCR: test this once we can store multiple slots
        foreach ( $current->getSlotRoles() as $role ) {
            if ( !$target->hasSlot( $role ) ) {
                $updater->removeSlot( $role );
            }
        }
 
        $updater->setOriginalRevisionId( $target->getId() );
        // Do not call setUndidRevisionId(), that causes an extra "mw-undo" tag to be added (T190374)
        $updater->addTags( $tags );
 
        // TODO: this logic should not be in the storage layer, it's here for compatibility
        // with 1.31 behavior. Applying the 'autopatrol' right should be done in the same
        // place the 'bot' right is handled, which is currently in EditPage::attemptSave.
        if ( $wgUseRCPatrol && $this->getTitle()->userCan( 'autopatrol', $guser ) ) {
            $updater->setRcPatrolStatus( RecentChange::PRC_AUTOPATROLLED );
        }
 
        // Actually store the rollback
        $rev = $updater->saveRevision(
            CommentStoreComment::newUnsavedComment( $summary ),
            $flags
        );
 
        // Set patrolling and bot flag on the edits, which gets rollbacked.
        // This is done even on edit failure to have patrolling in that case (T64157).
        $set = [];
        if ( $bot && $guser->isAllowed( 'markbotedits' ) ) {
            // Mark all reverted edits as bot
            $set['rc_bot'] = 1;
        }
 
        if ( $wgUseRCPatrol ) {
            // Mark all reverted edits as patrolled
            $set['rc_patrolled'] = RecentChange::PRC_PATROLLED;
        }
 
        if ( count( $set ) ) {
            $actorWhere = ActorMigration::newMigration()->getWhere(
                $dbw,
                'rc_user',
                $current->getUser( RevisionRecord::RAW ),
                false
            );
            $dbw->update( 'recentchanges', $set,
                [ /* WHERE */
                    'rc_cur_id' => $current->getPageId(),
                    'rc_timestamp > ' . $dbw->addQuotes( $s->rev_timestamp ),
                    $actorWhere['conds'], // No tables/joins are needed for rc_user
                ],
                __METHOD__
            );
        }
 
        if ( !$updater->wasSuccessful() ) {
            return $updater->getStatus()->getErrorsArray();
        }
 
        // Report if the edit was not created because it did not change the content.
        if ( $updater->isUnchanged() ) {
            $resultDetails = [ 'current' => $legacyCurrent ];
            return [ [ 'alreadyrolled',
                    htmlspecialchars( $this->mTitle->getPrefixedText() ),
                    htmlspecialchars( $fromP ),
                    htmlspecialchars( $targetEditorForPublic ? $targetEditorForPublic->getName() : '' )
            ] ];
        }
 
        if ( $changingContentModel ) {
            // If the content model changed during the rollback,
            // make sure it gets logged to Special:Log/contentmodel
            $log = new ManualLogEntry( 'contentmodel', 'change' );
            $log->setPerformer( $guser );
            $log->setTarget( $this->mTitle );
            $log->setComment( $summary );
            $log->setParameters( [
                '4::oldmodel' => $currentContent->getModel(),
                '5::newmodel' => $targetContent->getModel(),
            ] );
 
            $logId = $log->insert( $dbw );
            $log->publish( $logId );
        }
 
        $revId = $rev->getId();
 
        Hooks::run( 'ArticleRollbackComplete', [ $this, $guser, $legacyTarget, $legacyCurrent ] );
 
        $resultDetails = [
            'summary' => $summary,
            'current' => $legacyCurrent,
            'target' => $legacyTarget,
            'newid' => $revId,
            'tags' => $tags
        ];
 
        // TODO: make this return a Status object and wrap $resultDetails in that.
        return [];
    }
 
    public static function onArticleCreate( Title $title ) {
        // TODO: move this into a PageEventEmitter service
 
        // Update existence markers on article/talk tabs...
        $other = $title->getOtherPage();
 
        $other->purgeSquid();
 
        $title->touchLinks();
        $title->purgeSquid();
        $title->deleteTitleProtection();
 
        MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $title );
 
        // Invalidate caches of articles which include this page
        DeferredUpdates::addUpdate(
            new HTMLCacheUpdate( $title, 'templatelinks', 'page-create' )
        );
 
        if ( $title->getNamespace() == NS_CATEGORY ) {
            // Load the Category object, which will schedule a job to create
            // the category table row if necessary. Checking a replica DB is ok
            // here, in the worst case it'll run an unnecessary recount job on
            // a category that probably doesn't have many members.
            Category::newFromTitle( $title )->getID();
        }
    }
 
    public static function onArticleDelete( Title $title ) {
        // TODO: move this into a PageEventEmitter service
 
        // Update existence markers on article/talk tabs...
        // Clear Backlink cache first so that purge jobs use more up-to-date backlink information
        BacklinkCache::get( $title )->clear();
        $other = $title->getOtherPage();
 
        $other->purgeSquid();
 
        $title->touchLinks();
        $title->purgeSquid();
 
        MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $title );
 
        // File cache
        HTMLFileCache::clearFileCache( $title );
        InfoAction::invalidateCache( $title );
 
        // Messages
        if ( $title->getNamespace() == NS_MEDIAWIKI ) {
            MessageCache::singleton()->updateMessageOverride( $title, null );
        }
 
        // Images
        if ( $title->getNamespace() == NS_FILE ) {
            DeferredUpdates::addUpdate(
                new HTMLCacheUpdate( $title, 'imagelinks', 'page-delete' )
            );
        }
 
        // User talk pages
        if ( $title->getNamespace() == NS_USER_TALK ) {
            $user = User::newFromName( $title->getText(), false );
            if ( $user ) {
                $user->setNewtalk( false );
            }
        }
 
        // Image redirects
        RepoGroup::singleton()->getLocalRepo()->invalidateImageRedirect( $title );
 
        // Purge cross-wiki cache entities referencing this page
        self::purgeInterwikiCheckKey( $title );
    }
 
    public static function onArticleEdit(
        Title $title,
        Revision $revision = null,
        $slotsChanged = null
    ) {
        // TODO: move this into a PageEventEmitter service
 
        if ( $slotsChanged === null || in_array( SlotRecord::MAIN,  $slotsChanged ) ) {
            // Invalidate caches of articles which include this page.
            // Only for the main slot, because only the main slot is transcluded.
            // TODO: MCR: not true for TemplateStyles! [SlotHandler]
            DeferredUpdates::addUpdate(
                new HTMLCacheUpdate( $title, 'templatelinks', 'page-edit' )
            );
        }
 
        // Invalidate the caches of all pages which redirect here
        DeferredUpdates::addUpdate(
            new HTMLCacheUpdate( $title, 'redirect', 'page-edit' )
        );
 
        MediaWikiServices::getInstance()->getLinkCache()->invalidateTitle( $title );
 
        // Purge CDN for this page only
        $title->purgeSquid();
        // Clear file cache for this page only
        HTMLFileCache::clearFileCache( $title );
 
        // Purge ?action=info cache
        $revid = $revision ? $revision->getId() : null;
        DeferredUpdates::addCallableUpdate( function () use ( $title, $revid ) {
            InfoAction::invalidateCache( $title, $revid );
        } );
 
        // Purge cross-wiki cache entities referencing this page
        self::purgeInterwikiCheckKey( $title );
    }
 
    private static function purgeInterwikiCheckKey( Title $title ) {
        global $wgEnableScaryTranscluding;
 
        if ( !$wgEnableScaryTranscluding ) {
            return; // @todo: perhaps this wiki is only used as a *source* for content?
        }
 
        DeferredUpdates::addCallableUpdate( function () use ( $title ) {
            $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
            $cache->resetCheckKey(
                // Do not include the namespace since there can be multiple aliases to it
                // due to different namespace text definitions on different wikis. This only
                // means that some cache invalidations happen that are not strictly needed.
                $cache->makeGlobalKey( 'interwiki-page', wfWikiID(), $title->getDBkey() )
            );
        } );
    }
 
    public function getCategories() {
        $id = $this->getId();
        if ( $id == 0 ) {
            return TitleArray::newFromResult( new FakeResultWrapper( [] ) );
        }
 
        $dbr = wfGetDB( DB_REPLICA );
        $res = $dbr->select( 'categorylinks',
            [ 'cl_to AS page_title, ' . NS_CATEGORY . ' AS page_namespace' ],
            // Have to do that since Database::fieldNamesWithAlias treats numeric indexes
            // as not being aliases, and NS_CATEGORY is numeric
            [ 'cl_from' => $id ],
            __METHOD__ );
 
        return TitleArray::newFromResult( $res );
    }
 
    public function getHiddenCategories() {
        $result = [];
        $id = $this->getId();
 
        if ( $id == 0 ) {
            return [];
        }
 
        $dbr = wfGetDB( DB_REPLICA );
        $res = $dbr->select( [ 'categorylinks', 'page_props', 'page' ],
            [ 'cl_to' ],
            [ 'cl_from' => $id, 'pp_page=page_id', 'pp_propname' => 'hiddencat',
                'page_namespace' => NS_CATEGORY, 'page_title=cl_to' ],
            __METHOD__ );
 
        if ( $res !== false ) {
            foreach ( $res as $row ) {
                $result[] = Title::makeTitle( NS_CATEGORY, $row->cl_to );
            }
        }
 
        return $result;
    }
 
    public function getAutoDeleteReason( &$hasHistory ) {
        return $this->getContentHandler()->getAutoDeleteReason( $this->getTitle(), $hasHistory );
    }
 
    public function updateCategoryCounts( array $added, array $deleted, $id = 0 ) {
        $id = $id ?: $this->getId();
        $type = MWNamespace::getCategoryLinkType( $this->getTitle()->getNamespace() );
 
        $addFields = [ 'cat_pages = cat_pages + 1' ];
        $removeFields = [ 'cat_pages = cat_pages - 1' ];
        if ( $type !== 'page' ) {
            $addFields[] = "cat_{$type}s = cat_{$type}s + 1";
            $removeFields[] = "cat_{$type}s = cat_{$type}s - 1";
        }
 
        $dbw = wfGetDB( DB_MASTER );
 
        if ( count( $added ) ) {
            $existingAdded = $dbw->selectFieldValues(
                'category',
                'cat_title',
                [ 'cat_title' => $added ],
                __METHOD__
            );
 
            // For category rows that already exist, do a plain
            // UPDATE instead of INSERT...ON DUPLICATE KEY UPDATE
            // to avoid creating gaps in the cat_id sequence.
            if ( count( $existingAdded ) ) {
                $dbw->update(
                    'category',
                    $addFields,
                    [ 'cat_title' => $existingAdded ],
                    __METHOD__
                );
            }
 
            $missingAdded = array_diff( $added, $existingAdded );
            if ( count( $missingAdded ) ) {
                $insertRows = [];
                foreach ( $missingAdded as $cat ) {
                    $insertRows[] = [
                        'cat_title'   => $cat,
                        'cat_pages'   => 1,
                        'cat_subcats' => ( $type === 'subcat' ) ? 1 : 0,
                        'cat_files'   => ( $type === 'file' ) ? 1 : 0,
                    ];
                }
                $dbw->upsert(
                    'category',
                    $insertRows,
                    [ 'cat_title' ],
                    $addFields,
                    __METHOD__
                );
            }
        }
 
        if ( count( $deleted ) ) {
            $dbw->update(
                'category',
                $removeFields,
                [ 'cat_title' => $deleted ],
                __METHOD__
            );
        }
 
        foreach ( $added as $catName ) {
            $cat = Category::newFromName( $catName );
            Hooks::run( 'CategoryAfterPageAdded', [ $cat, $this ] );
        }
 
        foreach ( $deleted as $catName ) {
            $cat = Category::newFromName( $catName );
            Hooks::run( 'CategoryAfterPageRemoved', [ $cat, $this, $id ] );
            // Refresh counts on categories that should be empty now (after commit, T166757)
            DeferredUpdates::addCallableUpdate( function () use ( $cat ) {
                $cat->refreshCountsIfEmpty();
            } );
        }
    }
 
    public function triggerOpportunisticLinksUpdate( ParserOutput $parserOutput ) {
        if ( wfReadOnly() ) {
            return;
        }
 
        if ( !Hooks::run( 'OpportunisticLinksUpdate',
            [ $this, $this->mTitle, $parserOutput ]
        ) ) {
            return;
        }
 
        $config = RequestContext::getMain()->getConfig();
 
        $params = [
            'isOpportunistic' => true,
            'rootJobTimestamp' => $parserOutput->getCacheTime()
        ];
 
        if ( $this->mTitle->areRestrictionsCascading() ) {
            // If the page is cascade protecting, the links should really be up-to-date
            JobQueueGroup::singleton()->lazyPush(
                RefreshLinksJob::newPrioritized( $this->mTitle, $params )
            );
        } elseif ( !$config->get( 'MiserMode' ) && $parserOutput->hasDynamicContent() ) {
            // Assume the output contains "dynamic" time/random based magic words.
            // Only update pages that expired due to dynamic content and NOT due to edits
            // to referenced templates/files. When the cache expires due to dynamic content,
            // page_touched is unchanged. We want to avoid triggering redundant jobs due to
            // views of pages that were just purged via HTMLCacheUpdateJob. In that case, the
            // template/file edit already triggered recursive RefreshLinksJob jobs.
            if ( $this->getLinksTimestamp() > $this->getTouched() ) {
                // If a page is uncacheable, do not keep spamming a job for it.
                // Although it would be de-duplicated, it would still waste I/O.
                $cache = ObjectCache::getLocalClusterInstance();
                $key = $cache->makeKey( 'dynamic-linksupdate', 'last', $this->getId() );
                $ttl = max( $parserOutput->getCacheExpiry(), 3600 );
                if ( $cache->add( $key, time(), $ttl ) ) {
                    JobQueueGroup::singleton()->lazyPush(
                        RefreshLinksJob::newDynamic( $this->mTitle, $params )
                    );
                }
            }
        }
    }
 
    public function getDeletionUpdates( $rev = null ) {
        if ( !$rev ) {
            wfDeprecated( __METHOD__ . ' without a RevisionRecord', '1.32' );
 
            try {
                $rev = $this->getRevisionRecord();
            } catch ( Exception $ex ) {
                // If we can't load the content, something is wrong. Perhaps that's why
                // the user is trying to delete the page, so let's not fail in that case.
                // Note that doDeleteArticleReal() will already have logged an issue with
                // loading the content.
                wfDebug( __METHOD__ . ' failed to load current revision of page ' . $this->getId() );
            }
        }
 
        if ( !$rev ) {
            $slotContent = [];
        } elseif ( $rev instanceof Content ) {
            wfDeprecated( __METHOD__ . ' with a Content object instead of a RevisionRecord', '1.32' );
 
            $slotContent = [ SlotRecord::MAIN => $rev ];
        } else {
            $slotContent = array_map( function ( SlotRecord $slot ) {
                return $slot->getContent( Revision::RAW );
            }, $rev->getSlots()->getSlots() );
        }
 
        $allUpdates = [ new LinksDeletionUpdate( $this ) ];
 
        // NOTE: once Content::getDeletionUpdates() is removed, we only need to content
        // model here, not the content object!
        // TODO: consolidate with similar logic in DerivedPageDataUpdater::getSecondaryDataUpdates()
        foreach ( $slotContent as $role => $content ) {
            $handler = $content->getContentHandler();
 
            $updates = $handler->getDeletionUpdates(
                $this->getTitle(),
                $role
            );
            $allUpdates = array_merge( $allUpdates, $updates );
 
            // TODO: remove B/C hack in 1.32!
            $legacyUpdates = $content->getDeletionUpdates( $this );
 
            // HACK: filter out redundant and incomplete LinksDeletionUpdate
            $legacyUpdates = array_filter( $legacyUpdates, function ( $update ) {
                return !( $update instanceof LinksDeletionUpdate );
            } );
 
            $allUpdates = array_merge( $allUpdates, $legacyUpdates );
        }
 
        Hooks::run( 'PageDeletionDataUpdates', [ $this->getTitle(), $rev, &$allUpdates ] );
 
        // TODO: hard deprecate old hook in 1.33
        Hooks::run( 'WikiPageDeletionUpdates', [ $this, $content, &$allUpdates ] );
        return $allUpdates;
    }
 
    public function isLocal() {
        return true;
    }
 
    public function getWikiDisplayName() {
        global $wgSitename;
        return $wgSitename;
    }
 
    public function getSourceURL() {
        return $this->getTitle()->getCanonicalURL();
    }
 
    public function getMutableCacheKeys( WANObjectCache $cache ) {
        $linkCache = MediaWikiServices::getInstance()->getLinkCache();
 
        return $linkCache->getMutableCacheKeys( $cache, $this->getTitle() );
    }
 
}