PHPSessionHandler: Implement SessionHandlerInterface

[mediawiki.git] / includes / deferred / SiteStatsUpdate.php

<?php
/**
 * 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
 */

/**
 * Class for handling updates to the site_stats table
 */
class SiteStatsUpdate implements DeferrableUpdate {
        /** @var int */
        protected $edits = 0;

        /** @var int */
        protected $pages = 0;

        /** @var int */
        protected $articles = 0;

        /** @var int */
        protected $users = 0;

        /** @var int */
        protected $images = 0;

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

        /**
         * @param array $deltas
         * @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;

                $this->doUpdateContextStats();

                $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' ) );
                }
        }

        /**
         * Do not call this outside of SiteStatsUpdate
         */
        public function tryDBUpdateInternal() {
                global $wgSiteStatsAsyncFactor;

                $dbw = wfGetDB( DB_MASTER );
                $lockKey = wfMemcKey( 'site_stats' ); // prepend wiki ID
                $pd = array();
                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->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_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__ );
                }
        }

        /**
         * @param IDatabase $dbw
         * @return bool|mixed
         */
        public static function cacheUpdate( $dbw ) {
                global $wgActiveUserDays;
                $dbr = wfGetDB( DB_SLAVE, '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 doUpdateContextStats() {
                $stats = RequestContext::getMain()->getStats();
                foreach ( array( 'edits', 'articles', 'pages', 'users', 'images' ) as $type ) {
                        $delta = $this->$type;
                        if ( $delta !== 0 ) {
                                $stats->updateCount( "site.$type", $delta );
                        }
                }
        }

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

        /**
         * @param string $type
         * @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 string $type
         * @param int $delta Delta (positive or negative)
         */
        protected function adjustPending( $type, $delta ) {
                $cache = ObjectCache::getMainStashInstance();
                if ( $delta < 0 ) { // decrement
                        $key = $this->getTypeCacheKey( $type, '-' );
                } else { // increment
                        $key = $this->getTypeCacheKey( $type, '+' );
                }

                $magnitude = abs( $delta );
                $cache->incrWithInit( $key, 0, $magnitude, $magnitude );
        }

        /**
         * Get pending delta counters for each stat type
         * @return array Positive and negative deltas for each type
         */
        protected function getPendingDeltas() {
                $cache = ObjectCache::getMainStashInstance();

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

                return $pending;
        }

        /**
         * Reduce pending delta counters after updates have been applied
         * @param array $pd Result of getPendingDeltas(), used for DB update
         */
        protected function removePendingDeltas( array $pd ) {
                $cache = ObjectCache::getMainStashInstance();

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