wikimedia/mediawiki-core

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includes/libs/objectcache/CachedBagOStuff.php

Summary

Maintainability
A
1 hr
Test Coverage
<?php
/**
 * Wrapper around a BagOStuff that caches data in memory
 *
 * 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
 * @ingroup Cache
 */

/**
 * Wrapper around a BagOStuff that caches data in memory
 *
 * The differences between CachedBagOStuff and MultiWriteBagOStuff are:
 * * CachedBagOStuff supports only one "backend".
 * * There's a flag for writes to only go to the in-memory cache.
 * * The in-memory cache is always updated.
 * * Locks go to the backend cache (with MultiWriteBagOStuff, it would wind
 *   up going to the HashBagOStuff used for the in-memory cache).
 *
 * @newable
 * @ingroup Cache
 */
class CachedBagOStuff extends BagOStuff {
    /** @var BagOStuff */
    protected $store;
    /** @var HashBagOStuff */
    protected $procCache;

    /**
     * @stable to call
     * @param BagOStuff $backend Permanent backend to use
     * @param array $params Parameters for HashBagOStuff
     */
    public function __construct( BagOStuff $backend, $params = [] ) {
        $params['keyspace'] = $backend->keyspace;
        parent::__construct( $params );

        $this->store = $backend;
        $this->procCache = new HashBagOStuff( $params );

        $this->attrMap = $backend->attrMap;
    }

    public function get( $key, $flags = 0 ) {
        $value = $this->procCache->get( $key, $flags );
        if ( $value !== false || $this->procCache->hasKey( $key ) ) {
            return $value;
        }

        $value = $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEY,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
        $this->set( $key, $value, self::TTL_INDEFINITE, self::WRITE_CACHE_ONLY );

        return $value;
    }

    public function getMulti( array $keys, $flags = 0 ) {
        $valueByKeyCached = [];

        $keysFetch = [];
        foreach ( $keys as $key ) {
            $value = $this->procCache->get( $key, $flags );
            if ( $value === false && !$this->procCache->hasKey( $key ) ) {
                $keysFetch[] = $key;
            } else {
                $valueByKeyCached[$key] = $value;
            }
        }

        $valueByKeyFetched = $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEYARR,
            self::RES_KEYMAP,
            [ $keysFetch, $flags ],
            $this
        );
        $this->setMulti( $valueByKeyFetched, self::TTL_INDEFINITE, self::WRITE_CACHE_ONLY );

        return $valueByKeyCached + $valueByKeyFetched;
    }

    public function set( $key, $value, $exptime = 0, $flags = 0 ) {
        $this->procCache->set( $key, $value, $exptime, $flags );

        if ( $this->fieldHasFlags( $flags, self::WRITE_CACHE_ONLY ) ) {
            return true;
        }

        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEY,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function delete( $key, $flags = 0 ) {
        $this->procCache->delete( $key, $flags );

        if ( $this->fieldHasFlags( $flags, self::WRITE_CACHE_ONLY ) ) {
            return true;
        }

        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEY,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function add( $key, $value, $exptime = 0, $flags = 0 ) {
        if ( $this->get( $key ) === false ) {
            return $this->set( $key, $value, $exptime, $flags );
        }

        // key already set
        return false;
    }

    // These just call the backend (tested elsewhere)
    // @codeCoverageIgnoreStart

    public function merge( $key, callable $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
        $this->procCache->delete( $key );

        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEY,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function changeTTL( $key, $exptime = 0, $flags = 0 ) {
        $this->procCache->delete( $key );

        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEY,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function lock( $key, $timeout = 6, $exptime = 6, $rclass = '' ) {
        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEY,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function unlock( $key ) {
        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEY,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function deleteObjectsExpiringBefore(
        $timestamp,
        callable $progress = null,
        $limit = INF,
        string $tag = null
    ) {
        $this->procCache->deleteObjectsExpiringBefore( $timestamp, $progress, $limit, $tag );

        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_NONKEY,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function setMulti( array $valueByKey, $exptime = 0, $flags = 0 ) {
        $this->procCache->setMulti( $valueByKey, $exptime, $flags );

        if ( $this->fieldHasFlags( $flags, self::WRITE_CACHE_ONLY ) ) {
            return true;
        }

        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEYMAP,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function deleteMulti( array $keys, $flags = 0 ) {
        $this->procCache->deleteMulti( $keys, $flags );

        if ( $this->fieldHasFlags( $flags, self::WRITE_CACHE_ONLY ) ) {
            return true;
        }

        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEYARR,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function changeTTLMulti( array $keys, $exptime, $flags = 0 ) {
        $this->procCache->changeTTLMulti( $keys, $exptime, $flags );

        if ( $this->fieldHasFlags( $flags, self::WRITE_CACHE_ONLY ) ) {
            return true;
        }

        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEYARR,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function incrWithInit( $key, $exptime, $step = 1, $init = null, $flags = 0 ) {
        $this->procCache->delete( $key );

        return $this->store->proxyCall(
            __FUNCTION__,
            self::ARG0_KEY,
            self::RES_NONKEY,
            func_get_args(),
            $this
        );
    }

    public function setMockTime( &$time ) {
        parent::setMockTime( $time );
        $this->procCache->setMockTime( $time );
        $this->store->setMockTime( $time );
    }

    // @codeCoverageIgnoreEnd
}