SiteStats.php

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<?php
class SiteStats {
    static $row, $loaded = false;
    static $jobs;
    static $pageCount = array();
    static $groupMemberCounts = array();

    static function recache() {
        self::load( true );
    }

    static function load( $recache = false ) {
        if ( self::$loaded && !$recache ) {
            return;
        }

        self::$row = self::loadAndLazyInit();

        # This code is somewhat schema-agnostic, because I'm changing it in a minor release -- TS
        if ( !isset( self::$row->ss_total_pages ) && self::$row->ss_total_pages == -1 ) {
            # Update schema
            $u = new SiteStatsUpdate( 0, 0, 0 );
            $u->doUpdate();
            self::$row = self::doLoad( wfGetDB( DB_SLAVE ) );
        }

        self::$loaded = true;
    }

    static function loadAndLazyInit() {
        wfDebug( __METHOD__ . ": reading site_stats from slave\n" );
        $row = self::doLoad( wfGetDB( DB_SLAVE ) );

        if ( !self::isSane( $row ) ) {
            // Might have just been initialized during this request? Underflow?
            wfDebug( __METHOD__ . ": site_stats damaged or missing on slave\n" );
            $row = self::doLoad( wfGetDB( DB_MASTER ) );
        }

        if ( !self::isSane( $row ) ) {
            // Normally the site_stats table is initialized at install time.
            // Some manual construction scenarios may leave the table empty or
            // broken, however, for instance when importing from a dump into a
            // clean schema with mwdumper.
            wfDebug( __METHOD__ . ": initializing damaged or missing site_stats\n" );

            SiteStatsInit::doAllAndCommit( wfGetDB( DB_SLAVE ) );

            $row = self::doLoad( wfGetDB( DB_MASTER ) );
        }

        if ( !self::isSane( $row ) ) {
            wfDebug( __METHOD__ . ": site_stats persistently nonsensical o_O\n" );
        }
        return $row;
    }

    static function doLoad( $db ) {
        return $db->selectRow( 'site_stats', array(
                'ss_row_id',
                'ss_total_views',
                'ss_total_edits',
                'ss_good_articles',
                'ss_total_pages',
                'ss_users',
                'ss_active_users',
                'ss_images',
            ), false, __METHOD__ );
    }

    static function views() {
        self::load();
        return self::$row->ss_total_views;
    }

    static function edits() {
        self::load();
        return self::$row->ss_total_edits;
    }

    static function articles() {
        self::load();
        return self::$row->ss_good_articles;
    }

    static function pages() {
        self::load();
        return self::$row->ss_total_pages;
    }

    static function users() {
        self::load();
        return self::$row->ss_users;
    }

    static function activeUsers() {
        self::load();
        return self::$row->ss_active_users;
    }

    static function images() {
        self::load();
        return self::$row->ss_images;
    }

    static function numberingroup( $group ) {
        if ( !isset( self::$groupMemberCounts[$group] ) ) {
            global $wgMemc;
            $key = wfMemcKey( 'SiteStats', 'groupcounts', $group );
            $hit = $wgMemc->get( $key );
            if ( !$hit ) {
                $dbr = wfGetDB( DB_SLAVE );
                $hit = $dbr->selectField(
                    'user_groups',
                    'COUNT(*)',
                    array( 'ug_group' => $group ),
                    __METHOD__
                );
                $wgMemc->set( $key, $hit, 3600 );
            }
            self::$groupMemberCounts[$group] = $hit;
        }
        return self::$groupMemberCounts[$group];
    }

    static function jobs() {
        if ( !isset( self::$jobs ) ) {
            $dbr = wfGetDB( DB_SLAVE );
            self::$jobs = array_sum( JobQueueGroup::singleton()->getQueueSizes() );
            /* Zero rows still do single row read for row that doesn't exist, but people are annoyed by that */
            if ( self::$jobs == 1 ) {
                self::$jobs = 0;
            }
        }
        return self::$jobs;
    }

    static function pagesInNs( $ns ) {
        wfProfileIn( __METHOD__ );
        if ( !isset( self::$pageCount[$ns] ) ) {
            $dbr = wfGetDB( DB_SLAVE );
            self::$pageCount[$ns] = (int)$dbr->selectField(
                'page',
                'COUNT(*)',
                array( 'page_namespace' => $ns ),
                __METHOD__
            );
        }
        wfProfileOut( __METHOD__ );
        return self::$pageCount[$ns];
    }

    private static function isSane( $row ) {
        if ( $row === false
            || $row->ss_total_pages < $row->ss_good_articles
            || $row->ss_total_edits < $row->ss_total_pages
            || $row->ss_users < $row->ss_active_users
        ) {
            return false;
        }
        // Now check for underflow/overflow
        foreach ( array(
            'ss_total_views',
            'ss_total_edits',
            'ss_good_articles',
            'ss_total_pages',
            'ss_users',
            'ss_active_users',
            'ss_images',
        ) as $member ) {
            if ( $row->$member > 2000000000 || $row->$member < 0 ) {
                return false;
            }
        }
        return true;
    }
}

class SiteStatsUpdate implements DeferrableUpdate {
    protected $views = 0;
    protected $edits = 0;
    protected $pages = 0;
    protected $articles = 0;
    protected $users = 0;
    protected $images = 0;

    // @todo deprecate this constructor
    function __construct( $views, $edits, $good, $pages = 0, $users = 0 ) {
        $this->views = $views;
        $this->edits = $edits;
        $this->articles = $good;
        $this->pages = $pages;
        $this->users = $users;
    }

    public static function factory( array $deltas ) {
        $update = new self( 0, 0, 0 );

        $fields = array( 'views', 'edits', 'pages', 'articles', 'users', 'images' );
        foreach ( $fields as $field ) {
            if ( isset( $deltas[$field] ) && $deltas[$field] ) {
                $update->$field = $deltas[$field];
            }
        }

        return $update;
    }

    public function doUpdate() {
        global $wgSiteStatsAsyncFactor;

        $rate = $wgSiteStatsAsyncFactor; // convenience
        // If set to do so, only do actual DB updates 1 every $rate times.
        // The other times, just update "pending delta" values in memcached.
        if ( $rate && ( $rate < 0 || mt_rand( 0, $rate - 1 ) != 0 ) ) {
            $this->doUpdatePendingDeltas();
        } else {
            // Need a separate transaction because this a global lock
            wfGetDB( DB_MASTER )->onTransactionIdle( array( $this, 'tryDBUpdateInternal' ) );
        }
    }

    public function tryDBUpdateInternal() {
        global $wgSiteStatsAsyncFactor;

        $dbw = wfGetDB( DB_MASTER );
        $lockKey = wfMemcKey( 'site_stats' ); // prepend wiki ID
        if ( $wgSiteStatsAsyncFactor ) {
            // Lock the table so we don't have double DB/memcached updates
            if ( !$dbw->lockIsFree( $lockKey, __METHOD__ )
                || !$dbw->lock( $lockKey, __METHOD__, 1 ) // 1 sec timeout
            ) {
                $this->doUpdatePendingDeltas();
                return;
            }
            $pd = $this->getPendingDeltas();
            // Piggy-back the async deltas onto those of this stats update....
            $this->views += ( $pd['ss_total_views']['+'] - $pd['ss_total_views']['-'] );
            $this->edits += ( $pd['ss_total_edits']['+'] - $pd['ss_total_edits']['-'] );
            $this->articles += ( $pd['ss_good_articles']['+'] - $pd['ss_good_articles']['-'] );
            $this->pages += ( $pd['ss_total_pages']['+'] - $pd['ss_total_pages']['-'] );
            $this->users += ( $pd['ss_users']['+'] - $pd['ss_users']['-'] );
            $this->images += ( $pd['ss_images']['+'] - $pd['ss_images']['-'] );
        }

        // Build up an SQL query of deltas and apply them...
        $updates = '';
        $this->appendUpdate( $updates, 'ss_total_views', $this->views );
        $this->appendUpdate( $updates, 'ss_total_edits', $this->edits );
        $this->appendUpdate( $updates, 'ss_good_articles', $this->articles );
        $this->appendUpdate( $updates, 'ss_total_pages', $this->pages );
        $this->appendUpdate( $updates, 'ss_users', $this->users );
        $this->appendUpdate( $updates, 'ss_images', $this->images );
        if ( $updates != '' ) {
            $dbw->update( 'site_stats', array( $updates ), array(), __METHOD__ );
        }

        if ( $wgSiteStatsAsyncFactor ) {
            // Decrement the async deltas now that we applied them
            $this->removePendingDeltas( $pd );
            // Commit the updates and unlock the table
            $dbw->unlock( $lockKey, __METHOD__ );
        }
    }

    public static function cacheUpdate( $dbw ) {
        global $wgActiveUserDays;
        $dbr = wfGetDB( DB_SLAVE, array( 'SpecialStatistics', 'vslow' ) );
        # Get non-bot users than did some recent action other than making accounts.
        # If account creation is included, the number gets inflated ~20+ fold on enwiki.
        $activeUsers = $dbr->selectField(
            'recentchanges',
            'COUNT( DISTINCT rc_user_text )',
            array(
                'rc_user != 0',
                'rc_bot' => 0,
                'rc_log_type != ' . $dbr->addQuotes( 'newusers' ) . ' OR rc_log_type IS NULL',
                'rc_timestamp >= ' . $dbr->addQuotes( $dbr->timestamp( wfTimestamp( TS_UNIX ) - $wgActiveUserDays * 24 * 3600 ) ),
            ),
            __METHOD__
        );
        $dbw->update(
            'site_stats',
            array( 'ss_active_users' => intval( $activeUsers ) ),
            array( 'ss_row_id' => 1 ),
            __METHOD__
        );
        return $activeUsers;
    }

    protected function doUpdatePendingDeltas() {
        $this->adjustPending( 'ss_total_views', $this->views );
        $this->adjustPending( 'ss_total_edits', $this->edits );
        $this->adjustPending( 'ss_good_articles', $this->articles );
        $this->adjustPending( 'ss_total_pages', $this->pages );
        $this->adjustPending( 'ss_users', $this->users );
        $this->adjustPending( 'ss_images', $this->images );
    }

    protected function appendUpdate( &$sql, $field, $delta ) {
        if ( $delta ) {
            if ( $sql ) {
                $sql .= ',';
            }
            if ( $delta < 0 ) {
                $sql .= "$field=$field-" . abs( $delta );
            } else {
                $sql .= "$field=$field+" . abs( $delta );
            }
        }
    }

    private function getTypeCacheKey( $type, $sign ) {
        return wfMemcKey( 'sitestatsupdate', 'pendingdelta', $type, $sign );
    }

    protected function adjustPending( $type, $delta ) {
        global $wgMemc;

        if ( $delta < 0 ) { // decrement
            $key = $this->getTypeCacheKey( $type, '-' );
        } else { // increment
            $key = $this->getTypeCacheKey( $type, '+' );
        }

        $magnitude = abs( $delta );
        if ( !$wgMemc->incr( $key, $magnitude ) ) { // not there?
            if ( !$wgMemc->add( $key, $magnitude ) ) { // race?
                $wgMemc->incr( $key, $magnitude );
            }
        }
    }

    protected function getPendingDeltas() {
        global $wgMemc;

        $pending = array();
        foreach ( array( 'ss_total_views', 'ss_total_edits',
            'ss_good_articles', 'ss_total_pages', 'ss_users', 'ss_images' ) as $type )
        {
            // Get pending increments and pending decrements
            $pending[$type]['+'] = (int)$wgMemc->get( $this->getTypeCacheKey( $type, '+' ) );
            $pending[$type]['-'] = (int)$wgMemc->get( $this->getTypeCacheKey( $type, '-' ) );
        }

        return $pending;
    }

    protected function removePendingDeltas( array $pd ) {
        global $wgMemc;

        foreach ( $pd as $type => $deltas ) {
            foreach ( $deltas as $sign => $magnitude ) {
                // Lower the pending counter now that we applied these changes
                $wgMemc->decr( $this->getTypeCacheKey( $type, $sign ), $magnitude );
            }
        }
    }
}

class SiteStatsInit {

    // Database connection
    private $db;

    // Various stats
    private $mEdits, $mArticles, $mPages, $mUsers, $mViews, $mFiles = 0;

    public function __construct( $database = false ) {
        if ( $database instanceof DatabaseBase ) {
            $this->db = $database;
        } else {
            $this->db = wfGetDB( $database ? DB_MASTER : DB_SLAVE );
        }
    }

    public function edits() {
        $this->mEdits = $this->db->selectField( 'revision', 'COUNT(*)', '', __METHOD__ );
        $this->mEdits += $this->db->selectField( 'archive', 'COUNT(*)', '', __METHOD__ );
        return $this->mEdits;
    }

    public function articles() {
        global $wgArticleCountMethod;

        $tables = array( 'page' );
        $conds = array(
            'page_namespace' => MWNamespace::getContentNamespaces(),
            'page_is_redirect' => 0,
        );

        if ( $wgArticleCountMethod == 'link' ) {
            $tables[] = 'pagelinks';
            $conds[] = 'pl_from=page_id';
        } elseif ( $wgArticleCountMethod == 'comma' ) {
            // To make a correct check for this, we would need, for each page,
            // to load the text, maybe uncompress it, maybe decode it and then
            // check if there's one comma.
            // But one thing we are sure is that if the page is empty, it can't
            // contain a comma :)
            $conds[] = 'page_len > 0';
        }

        $this->mArticles = $this->db->selectField( $tables, 'COUNT(DISTINCT page_id)',
            $conds, __METHOD__ );
        return $this->mArticles;
    }

    public function pages() {
        $this->mPages = $this->db->selectField( 'page', 'COUNT(*)', '', __METHOD__ );
        return $this->mPages;
    }

    public function users() {
        $this->mUsers = $this->db->selectField( 'user', 'COUNT(*)', '', __METHOD__ );
        return $this->mUsers;
    }

    public function views() {
        $this->mViews = $this->db->selectField( 'page', 'SUM(page_counter)', '', __METHOD__ );
        return $this->mViews;
    }

    public function files() {
        $this->mFiles = $this->db->selectField( 'image', 'COUNT(*)', '', __METHOD__ );
        return $this->mFiles;
    }

    public static function doAllAndCommit( $database, array $options = array() ) {
        $options += array( 'update' => false, 'views' => true, 'activeUsers' => false );

        // Grab the object and count everything
        $counter = new SiteStatsInit( $database );

        $counter->edits();
        $counter->articles();
        $counter->pages();
        $counter->users();
        $counter->files();

        // Only do views if we don't want to not count them
        if ( $options['views'] ) {
            $counter->views();
        }

        // Update/refresh
        if ( $options['update'] ) {
            $counter->update();
        } else {
            $counter->refresh();
        }

        // Count active users if need be
        if ( $options['activeUsers'] ) {
            SiteStatsUpdate::cacheUpdate( wfGetDB( DB_MASTER ) );
        }
    }

    public function update() {
        list( $values, $conds ) = $this->getDbParams();
        $dbw = wfGetDB( DB_MASTER );
        $dbw->update( 'site_stats', $values, $conds, __METHOD__ );
    }

    public function refresh() {
        list( $values, $conds, $views ) = $this->getDbParams();
        $dbw = wfGetDB( DB_MASTER );
        $dbw->delete( 'site_stats', $conds, __METHOD__ );
        $dbw->insert( 'site_stats', array_merge( $values, $conds, $views ), __METHOD__ );
    }

    private function getDbParams() {
        $values = array(
            'ss_total_edits' => $this->mEdits,
            'ss_good_articles' => $this->mArticles,
            'ss_total_pages' => $this->mPages,
            'ss_users' => $this->mUsers,
            'ss_images' => $this->mFiles
        );
        $conds = array( 'ss_row_id' => 1 );
        $views = array( 'ss_total_views' => $this->mViews );
        return array( $values, $conds, $views );
    }
}