MemcachedBagOStuff.php

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<?php
class MemcachedBagOStuff extends BagOStuff {
    protected $client;
 
    function __construct( array $params ) {
        parent::__construct( $params );
 
        $this->attrMap[self::ATTR_SYNCWRITES] = self::QOS_SYNCWRITES_BE; // unreliable
    }
 
    protected function applyDefaultParams( $params ) {
        return $params + [
            'compress_threshold' => 1500,
            'connect_timeout' => 0.5,
            'debug' => false
        ];
    }
 
    protected function doGet( $key, $flags = 0 ) {
        $casToken = null;
 
        return $this->getWithToken( $key, $casToken, $flags );
    }
 
    protected function getWithToken( $key, &$casToken, $flags = 0 ) {
        return $this->client->get( $this->validateKeyEncoding( $key ), $casToken );
    }
 
    public function set( $key, $value, $exptime = 0, $flags = 0 ) {
        return $this->client->set( $this->validateKeyEncoding( $key ), $value,
            $this->fixExpiry( $exptime ) );
    }
 
    protected function cas( $casToken, $key, $value, $exptime = 0 ) {
        return $this->client->cas( $casToken, $this->validateKeyEncoding( $key ),
            $value, $this->fixExpiry( $exptime ) );
    }
 
    public function delete( $key ) {
        return $this->client->delete( $this->validateKeyEncoding( $key ) );
    }
 
    public function add( $key, $value, $exptime = 0 ) {
        return $this->client->add( $this->validateKeyEncoding( $key ), $value,
            $this->fixExpiry( $exptime ) );
    }
 
    public function merge( $key, callable $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
        return $this->mergeViaCas( $key, $callback, $exptime, $attempts );
    }
 
    public function changeTTL( $key, $exptime = 0 ) {
        return $this->client->touch( $this->validateKeyEncoding( $key ),
            $this->fixExpiry( $exptime ) );
    }
 
    public function getClient() {
        return $this->client;
    }
 
    public function makeKeyInternal( $keyspace, $args ) {
        // Memcached keys have a maximum length of 255 characters. From that,
        // subtract the number of characters we need for the keyspace and for
        // the separator character needed for each argument. To handle some
        // custom prefixes used by thing like WANObjectCache, limit to 205.
        $charsLeft = 205 - strlen( $keyspace ) - count( $args );
 
        $args = array_map(
            function ( $arg ) use ( &$charsLeft ) {
                $arg = strtr( $arg, ' ', '_' );
 
                // Make sure %, #, and non-ASCII chars are escaped
                $arg = preg_replace_callback(
                    '/[^\x21-\x22\x24\x26-\x39\x3b-\x7e]+/',
                    function ( $m ) {
                        return rawurlencode( $m[0] );
                    },
                    $arg
                );
 
                // 33 = 32 characters for the MD5 + 1 for the '#' prefix.
                if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
                    $arg = '#' . md5( $arg );
                }
 
                $charsLeft -= strlen( $arg );
                return $arg;
            },
            $args
        );
 
        if ( $charsLeft < 0 ) {
            return $keyspace . ':BagOStuff-long-key:##' . md5( implode( ':', $args ) );
        }
 
        return $keyspace . ':' . implode( ':', $args );
    }
 
    public function validateKeyEncoding( $key ) {
        if ( preg_match( '/[^\x21-\x7e]+/', $key ) ) {
            throw new Exception( "Key contains invalid characters: $key" );
        }
        return $key;
    }
 
    function fixExpiry( $expiry ) {
        if ( $expiry > 2592000 && $expiry < 1000000000 ) {
            $expiry = 2592000;
        }
        return (int)$expiry;
    }
 
    protected function debugLog( $text ) {
        $this->logger->debug( $text );
    }
 
    public function modifySimpleRelayEvent( array $event ) {
        if ( array_key_exists( 'val', $event ) ) {
            $event['flg'] = 0; // data is not serialized nor gzipped (for memcached driver)
        }
 
        return $event;
    }
}