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[mediawiki.git] / includes / SiteStats.php

<?php
/**
 * Accessors and mutators for the site-wide statistics.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

/**
 * Static accessor class for site_stats and related things
 */
class SiteStats {
        static $row, $loaded = false;
        static $jobs;
        static $pageCount = array();
        static $groupMemberCounts = array();

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

        /**
         * @param $recache bool
         */
        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;
        }

        /**
         * @return Bool|ResultWrapper
         */
        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;
        }

        /**
         * @param $db DatabaseBase
         * @return Bool|ResultWrapper
         */
        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__ );
        }

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

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

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

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

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

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

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

        /**
         * Find the number of users in a given user group.
         * @param string $group name of group
         * @return Integer
         */
        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];
        }

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

        /**
         * @param $ns int
         *
         * @return int
         */
        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];
        }

        /**
         * Is the provided row of site stats sane, or should it be regenerated?
         *
         * @param $row
         *
         * @return bool
         */
        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 for handling updates to the site_stats table
 */
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;
        }

        /**
         * @param $deltas Array
         * @return SiteStatsUpdate
         */
        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 {
                        $dbw = wfGetDB( DB_MASTER );

                        $lockKey = wfMemcKey( 'site_stats' ); // prepend wiki ID
                        if ( $rate ) {
                                // Lock the table so we don't have double DB/memcached updates
                                if ( !$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']['-'] );
                        }

                        // Need a separate transaction because this a global lock
                        $dbw->begin( __METHOD__ );

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

                        $dbw->commit( __METHOD__ );
                }
        }

        /**
         * @param $dbw DatabaseBase
         * @return bool|mixed
         */
        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 );
        }

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

        /**
         * @param $type string
         * @param string $sign ('+' or '-')
         * @return string
         */
        private function getTypeCacheKey( $type, $sign ) {
                return wfMemcKey( 'sitestatsupdate', 'pendingdelta', $type, $sign );
        }

        /**
         * Adjust the pending deltas for a stat type.
         * Each stat type has two pending counters, one for increments and decrements
         * @param $type string
         * @param $delta integer Delta (positive or negative)
         * @return void
         */
        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 );
                        }
                }
        }

        /**
         * Get pending delta counters for each stat type
         * @return Array Positive and negative deltas for each type
         * @return void
         */
        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;
        }

        /**
         * Reduce pending delta counters after updates have been applied
         * @param array $pd Result of getPendingDeltas(), used for DB update
         * @return void
         */
        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 designed for counting of stats.
 */
class SiteStatsInit {

        // Database connection
        private $db;

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

        /**
         * Constructor
         * @param $database Boolean or DatabaseBase:
         * - Boolean: whether to use the master DB
         * - DatabaseBase: database connection to use
         */
        public function __construct( $database = false ) {
                if ( $database instanceof DatabaseBase ) {
                        $this->db = $database;
                } else {
                        $this->db = wfGetDB( $database ? DB_MASTER : DB_SLAVE );
                }
        }

        /**
         * Count the total number of edits
         * @return Integer
         */
        public function edits() {
                $this->mEdits = $this->db->selectField( 'revision', 'COUNT(*)', '', __METHOD__ );
                $this->mEdits += $this->db->selectField( 'archive', 'COUNT(*)', '', __METHOD__ );
                return $this->mEdits;
        }

        /**
         * Count pages in article space(s)
         * @return Integer
         */
        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;
        }

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

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

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

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

        /**
         * Do all updates and commit them. More or less a replacement
         * for the original initStats, but without output.
         *
         * @param $database DatabaseBase|bool
         * - Boolean: whether to use the master DB
         * - DatabaseBase: database connection to use
         * @param array $options of options, may contain the following values
         * - update Boolean: whether to update the current stats (true) or write fresh (false) (default: false)
         * - views Boolean: when true, do not update the number of page views (default: true)
         * - activeUsers Boolean: whether to update the number of active users (default: false)
         */
        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 ) );
                }
        }

        /**
         * Update the current row with the selected values
         */
        public function update() {
                list( $values, $conds ) = $this->getDbParams();
                $dbw = wfGetDB( DB_MASTER );
                $dbw->update( 'site_stats', $values, $conds, __METHOD__ );
        }

        /**
         * Refresh site_stats. Erase the current record and save all
         * the new values.
         */
        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__ );
        }

        /**
         * Return three arrays of params for the db queries
         * @return Array
         */
        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 );
        }
}