APCUBagOStuff.php

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<?php
class APCUBagOStuff extends MediumSpecificBagOStuff {
    private $nativeSerialize;
    private $useIncrTTLArg;
 
    private const KEY_SUFFIX = ':4';
 
    private static $CAS_MAX_ATTEMPTS = 100;
 
    public function __construct( array $params = [] ) {
        $params['segmentationSize'] = $params['segmentationSize'] ?? INF;
        parent::__construct( $params );
        // The extension serializer is still buggy, unlike "php" and "igbinary"
        $this->nativeSerialize = ( ini_get( 'apc.serializer' ) !== 'default' );
        $this->useIncrTTLArg = version_compare( phpversion( 'apcu' ), '5.1.12', '>=' );
        // Avoid back-dated values that expire too soon. In particular, regenerating a hot
        // key before it expires should never have the end-result of purging that key. Using
        // the web request time becomes increasingly problematic the longer the request lasts.
        ini_set( 'apc.use_request_time', '0' );
    }
 
    protected function doGet( $key, $flags = 0, &$casToken = null ) {
        $casToken = null;
 
        $blob = apcu_fetch( $key . self::KEY_SUFFIX );
        $value = $this->nativeSerialize ? $blob : $this->unserialize( $blob );
        if ( $value !== false ) {
            $casToken = $blob; // don't bother hashing this
        }
 
        return $value;
    }
 
    protected function doSet( $key, $value, $exptime = 0, $flags = 0 ) {
        $blob = $this->nativeSerialize ? $value : $this->getSerialized( $value, $key );
        $ttl = $this->getExpirationAsTTL( $exptime );
        $success = apcu_store( $key . self::KEY_SUFFIX, $blob, $ttl );
        return $success;
    }
 
    protected function doAdd( $key, $value, $exptime = 0, $flags = 0 ) {
        $blob = $this->nativeSerialize ? $value : $this->getSerialized( $value, $key );
        $ttl = $this->getExpirationAsTTL( $exptime );
        $success = apcu_add( $key . self::KEY_SUFFIX, $blob, $ttl );
        return $success;
    }
 
    protected function doDelete( $key, $flags = 0 ) {
        apcu_delete( $key . self::KEY_SUFFIX );
 
        return true;
    }
 
    public function incr( $key, $value = 1, $flags = 0 ) {
        $result = false;
 
        // https://github.com/krakjoe/apcu/issues/166
        for ( $i = 0; $i < self::$CAS_MAX_ATTEMPTS; ++$i ) {
            $oldCount = apcu_fetch( $key . self::KEY_SUFFIX );
            if ( !is_int( $oldCount ) ) {
                break;
            }
            $count = $oldCount + (int)$value;
            if ( apcu_cas( $key . self::KEY_SUFFIX, $oldCount, $count ) ) {
                $result = $count;
                break;
            }
        }
 
        return $result;
    }
 
    public function decr( $key, $value = 1, $flags = 0 ) {
        $result = false;
 
        // https://github.com/krakjoe/apcu/issues/166
        for ( $i = 0; $i < self::$CAS_MAX_ATTEMPTS; ++$i ) {
            $oldCount = apcu_fetch( $key . self::KEY_SUFFIX );
            if ( !is_int( $oldCount ) ) {
                break;
            }
            $count = $oldCount - (int)$value;
            if ( apcu_cas( $key . self::KEY_SUFFIX, $oldCount, $count ) ) {
                $result = $count;
                break;
            }
        }
 
        return $result;
    }
 
    public function incrWithInit( $key, $exptime, $value = 1, $init = null, $flags = 0 ) {
        $init = is_int( $init ) ? $init : $value;
        // Use apcu 5.1.12 $ttl argument if apcu_inc() will initialize to $init:
        // https://www.php.net/manual/en/function.apcu-inc.php
        if ( $value === $init && $this->useIncrTTLArg ) {
            $ttl = $this->getExpirationAsTTL( $exptime );
            $result = apcu_inc( $key . self::KEY_SUFFIX, $value, $success, $ttl );
        } else {
            $result = false;
            for ( $i = 0; $i < self::$CAS_MAX_ATTEMPTS; ++$i ) {
                $oldCount = apcu_fetch( $key . self::KEY_SUFFIX );
                if ( $oldCount === false ) {
                    $count = (int)$init;
                    $ttl = $this->getExpirationAsTTL( $exptime );
                    if ( apcu_add( $key . self::KEY_SUFFIX, $count, $ttl ) ) {
                        $result = $count;
                        break;
                    }
                } elseif ( is_int( $oldCount ) ) {
                    $count = $oldCount + (int)$value;
                    if ( apcu_cas( $key . self::KEY_SUFFIX, $oldCount, $count ) ) {
                        $result = $count;
                        break;
                    }
                } else {
                    break;
                }
            }
        }
 
        return $result;
    }
}