memcached-redux-3.0.php

<?php
/*
Plugin Name: Memcached Redux
Description: The real Memcached (not Memcache) backend for the WP Object Cache.
Version: 3.0
Plugin URI: http://wordpress.org/extend/plugins/memcached/
Author: Scott Taylor - uses code from Ryan Boren, Denis de Bernardy, Matt Martz

Install this file to wp-content/object-cache.php
*/

// Users with setups where multiple installs share a common wp-config.php or $table_prefix
// can use this to guarantee uniqueness for the keys generated by this object cache
if ( ! defined( 'WP_CACHE_KEY_SALT' ) )
  define( 'WP_CACHE_KEY_SALT', '' );

/**
 * Wrap WP_Object_Cache
 *
 * @global WP_Object_Cache $wp_object_cache
 */
function wp_cache_init() {
	$GLOBALS['wp_object_cache'] = new WP_Object_Cache();
}

function wp_cache_add_global_groups( $groups ) {
	$GLOBALS['wp_object_cache']->add_global_groups( $groups );
}

function wp_cache_add_non_persistent_groups( $groups ) {
	$GLOBALS['wp_object_cache']->add_non_persistent_groups( $groups );
}

function wp_cache_close() {
	return $GLOBALS['wp_object_cache']->close();
}

function wp_cache_flush() {
	return $GLOBALS['wp_object_cache']->flush();
}

function wp_cache_switch_to_blog( $blog_id ) {
	return $GLOBALS['wp_object_cache']->switch_to_blog( $blog_id );
}

/**
 * Wrap WP_Cache_Bucket
 *
 */

/**
 *
 * @param string $key
 * @param mixed $data
 * @param string $group
 * @param int $expire
 * @return mixed
 */
function wp_cache_add( $key, $data, $group = '', $expire = 0 ) {
	$bucket = WP_Cache_Bucket::get_instance( $group );
	return $bucket->add( $key, $data, $expire );
}
/**
 *
 * @param string $key
 * @param int $n
 * @param string $group
 * @return int
 */
function wp_cache_incr( $key, $n = 1, $group = '' ) {
	$bucket = WP_Cache_Bucket::get_instance( $group );
	return $bucket->incr( $key, $n );
}
/**
 *
 * @param string $key
 * @param int $n
 * @param string $group
 * @return int
 */
function wp_cache_decr( $key, $n = 1, $group = '' ) {
	$bucket = WP_Cache_Bucket::get_instance( $group );
	return $bucket->decr( $key, $n );
}
/**
 *
 * @param string $key
 * @param mixed $data
 * @param string $group
 * @param int $expire
 * @return
 */
function wp_cache_replace( $key, $data, $group = '', $expire = 0 ) {
	$bucket = WP_Cache_Bucket::get_instance( $group );
	return $bucket->replace( $key, $data, $expire );
}
/**
 *
 * @param string $key
 * @param string $group
 * @return type
 */
function wp_cache_delete( $key, $group = '' ) {
	$bucket = WP_Cache_Bucket::get_instance( $group );
	return $bucket->delete( $key );
}
/**
 *
 * @param string $key
 * @param string $group
 * @return mixed
 */
function wp_cache_get( $key, $group = '' ) {
	$bucket = WP_Cache_Bucket::get_instance( $group );
	return $bucket->get( $key );
}
/**
 *
 * @param string $key
 * @param mixed $data
 * @param string $group
 * @param int $expire
 * @return mixed
 */
function wp_cache_set( $key, $data, $group = '', $expire = 0 ) {
	$bucket = WP_Cache_Bucket::get_instance( $group );
	if ( defined( 'WP_INSTALLING' ) == false )
		return $bucket->set( $key, $data, $expire );
	else
		return $bucket->delete( $key );
}
/**
 *
 * @param array $keys
 * @param string $group
 * @return array
 */
function wp_cache_get_multi( $keys, $group = 'default' ) {
	$bucket = WP_Cache_Bucket::get_instance( $group );
	return $bucket->get_multi( $keys );
}
/**
 *
 * @param array $keys
 * @param string $group
 * @return array
 */
function wp_cache_set_multi( $items, $expire = 0, $group = 'default' ) {
	$bucket = WP_Cache_Bucket::get_instance( $group );
	return $bucket->set_multi( $items, $expire );
}

class WP_Cache_Bucket {
	static $instances = array();
	/**
	 * Cache group
	 *
	 * @var string
	 */
	public $bucket;
	/**
	 * Whether cache group is a global group
	 *
	 * @var boolean
	 */
	public $is_global;
	/**
	 * Decorator
	 *
	 * @var WP_Object_Cache
	 */
	private $wp_cache;
	/**
	 * Private bucket cache
	 *
	 * @var array
	 */
	private $cache = array();
	/**
	 * Encrypted group token
	 *
	 * @var string
	 */
	private $group;
	/**
	 * Memcached bucket
	 *
	 * @var Memcached
	 */
	private $mc;

	private function __construct( $bucket = 'default' ) {
		$this->bucket = empty( $bucket ) ? 'default' : $bucket;
		$this->wp_cache =& $GLOBALS['wp_object_cache'];
		$this->mc =& $this->wp_cache->get_mc( $bucket );

		$this->group = $this->mc->get( $this->encrypt( $this->bucket, 'bucket' ) );

		$this->is_global = in_array( $this->bucket, $this->wp_cache->global_groups );

		if ( empty( $this->group ) )
			$this->flush();
	}

	public function is_falsey( $value ) {
		return NULL === $value || false === $value || ( is_integer( $value ) && -1 == $value );
	}

	public static function get_instance( $bucket ) {
		if ( empty( $GLOBALS['wp_object_cache'] ) )
			return;

		if ( ! isset( self::$instances[$bucket] ) )
			self::$instances[$bucket] = new WP_Cache_Bucket( $bucket );

		return self::$instances[$bucket];
	}

	public function encrypt( $key, $group = false ) {
		if ( $group )
			return $this->wp_cache->key( $key, $group );
		else
			return $this->wp_cache->key( $key, $this->group );
	}

	function get( $id ) {
		$key = $this->encrypt( $id );

		if ( isset( $this->cache[$key] ) ) {
 			$value = is_object( $this->cache[$key] ) ? clone $this->cache[$key] : $this->cache[$key];
		} else if ( in_array( $this->bucket, $this->wp_cache->no_mc_groups ) ) {
			$this->cache[$key] = $value = false;
		} else {
			$value = $this->mc->get( $key );
			if ( $this->is_falsey( $value ) )
				$value = false;
			$this->cache[$key] = $value;
		}

		if ( 'checkthedatabaseplease' === $value ) {
			unset( $this->cache[$key] );
			$value = false;
		}

		return $value;
	}

	function set( $id, $data, $expire = 0 ) {
		$key = $this->encrypt( $id );

		if ( isset( $this->cache[$key] ) && ( 'checkthedatabaseplease' === $this->cache[$key] ) )
			return false;

		if ( is_object( $data ) )
			$data = clone $data;

		$this->cache[$key] = $data;

		if ( in_array( $this->bucket, $this->wp_cache->no_mc_groups ) )
			return true;

		$expire = empty( $expire ) ? $this->wp_cache->default_expiration : $expire;
		$this->mc->set( $key, $data, $expire );
		$result = $data;

		return $result;
	}

	function get_multi( $keys ) {
		$return = array();
		$gets = array();
		foreach ( $keys as $id ) {
			$key = $this->encrypt( $id );

			if ( isset( $this->cache[$key] ) ) {
				if ( is_object( $this->cache[$key] ) )
					$return[$key] = clone $this->cache[$key];
				else
					$return[$key] = $this->cache[$key];
			} else if ( in_array( $this->bucket, $this->wp_cache->no_mc_groups ) ) {
				$return[$key] = false;
			} else {
				$gets[$key] = $key;
			}
		}

		if ( ! empty( $gets ) ) {
			$null = null;
			$results = $this->mc->getMulti( $gets, $null, Memcached::GET_PRESERVE_ORDER );
			$joined = array_combine( array_keys( $gets ), array_values( $results ) );
			$return = array_merge( $return, $joined );
		}

		$this->cache = array_merge( $this->cache, $return );
		return array_values( $return );
	}

	function set_multi( $items, $expire = 0 ) {
		$sets = array();
		$expire = empty( $expire ) ? $this->wp_cache->default_expiration : $expire;

		foreach ( $items as $item ) {
			list( $id, $data ) = $item;

			$key = $this->encrypt( $id );

			if ( 'checkthedatabaseplease' === $this->cache[$key] )
				continue;

			if ( is_object( $data ) )
				$data = clone $data;

			$this->cache[$key] = $data;

			if ( in_array( $this->bucket, $this->wp_cache->no_mc_groups ) )
				continue;

			$sets[$key] = $data;
		}

		if ( ! empty( $sets ) )
			$this->mc->setMulti( $sets, $expire );
	}

	function add( $id, $data, $expire = 0 ) {
		$key = $this->encrypt( $id );

		if ( is_object( $data ) )
			$data = clone $data;

		if ( in_array( $this->bucket, $this->wp_cache->no_mc_groups ) ) {
			$this->cache[$key] = $data;
			return true;
		} elseif ( isset( $this->cache[$key] ) && false !== $this->cache[$key] ) {
			return false;
		}

		$expire = empty( $expire ) ? $this->wp_cache->default_expiration : $expire;
		$result = $this->mc->add( $key, $data, $expire );

		if ( false !== $result )
			$this->cache[$key] = $data;

		return $result;
	}

	function replace( $id, $data, $expire = 0 ) {
		$key = $this->encrypt( $id );
		$expire = empty( $expire ) ? $this->wp_cache->default_expiration : $expire;

		if ( is_object( $data ) )
			$data = clone $data;

		$result = $this->mc->replace( $key, $data, false, $expire );
		if ( false !== $result )
			$this->cache[$key] = $data;
		return $result;
	}

	function delete( $id ) {
		$key = $this->encrypt( $id );

		if ( in_array( $this->bucket, $this->wp_cache->no_mc_groups ) ) {
			unset( $this->cache[$key] );
			return true;
		}

		$result = $this->mc->delete( $key );

		if ( false !== $result )
			unset( $this->cache[$key] );

		return $result;
	}

	function incr( $id, $n = 1 ) {
		$key = $this->encrypt( $id );
		$this->cache[$key] = $this->mc->increment( $key, $n );
		return $this->cache[$key];
	}

	function decr( $id, $n = 1 ) {
		$key = $this->encrypt( $id );
		$this->cache[$key] = $this->mc->decrement( $key, $n );
		return $this->cache[$key];
	}

	public function purge( $key ) {
		unset( $this->cache[$key] );
		$this->delete( $key );
	}

	public function flush() {
		$key = uniqid( $this->is_global ? 'global_' : '' );
		$this->mc->set( $this->encrypt( $this->bucket, 'bucket' ), $key, 0 );
		$this->group = $key;
	}
}

class WP_Object_Cache {
	var $global_groups = array();

	var $no_mc_groups = array();

	var $cache = array();
	var $mc = array();

	var $cache_enabled = true;
	var $default_expiration = 0;

	function __construct() {
		global $memcached_servers, $blog_id, $table_prefix;

		$buckets = ! empty( $memcached_servers ) ? $memcached_servers : array( '127.0.0.1' );

		reset( $buckets );
		if ( is_int( key( $buckets ) ) )
			$buckets = array( 'default' => $buckets );

		foreach ( $buckets as $bucket => $servers ) {
			$this->mc[$bucket] = new Memcached();

			$instances = array();
			foreach ( $servers as $server  ) {
				@list( $node, $port ) = explode( ':', $server );
				if ( empty( $port ) )
					$port = ini_get( 'memcache.default_port' );
				$port = intval( $port );
				if ( ! $port )
					$port = 11211;

				$instances[] = array( $node, $port, 1 );
			}
			$this->mc[$bucket]->addServers( $instances );
		}

		$this->global_prefix = '';
		$this->blog_prefix = '';

		if ( function_exists( 'is_multisite' ) ) {
			$this->global_prefix = ( is_multisite() || defined( 'CUSTOM_USER_TABLE' ) && defined( 'CUSTOM_USER_META_TABLE' ) ) ? '' : $table_prefix;
			$this->blog_prefix = ( is_multisite() ? $blog_id : $table_prefix ) . ':';
		}
	}

	function get_mc( $group ) {
		if ( isset( $this->mc[$group] ) )
			return $this->mc[$group];

		return $this->mc['default'];
	}

	function add_global_groups( $groups ) {
		if ( ! is_array( $groups ) )
			$groups = (array) $groups;

		$this->global_groups = array_merge( $this->global_groups, $groups );
		$this->global_groups = array_unique( $this->global_groups );
	}

	function add_non_persistent_groups( $groups ) {
		if ( ! is_array( $groups ) )
			$groups = (array) $groups;

		$this->no_mc_groups = array_merge( $this->no_mc_groups, $groups );
		$this->no_mc_groups = array_unique( $this->no_mc_groups );
	}

	function switch_to_blog( $blog_id ) {
		global $table_prefix;
		$blog_id = (int) $blog_id;
		$this->blog_prefix = ( is_multisite() ? $blog_id : $table_prefix ) . ':';
	}

	function key( $key, $group ) {
		if ( empty( $group ) )
			$group = 'default';

		if ( false !== array_search( $group, $this->global_groups ) )
			$prefix = $this->global_prefix;
		else
			$prefix = $this->blog_prefix;

		return preg_replace( '/\s+/', '', WP_CACHE_KEY_SALT . "$prefix$group:$key" );
	}

	function close() {
		// Silence is Golden.
	}

	function flush() {
		// Don't flush if multi-blog.
		if ( function_exists( 'is_site_admin' ) || defined( 'CUSTOM_USER_TABLE' ) && defined( 'CUSTOM_USER_META_TABLE' ) )
			return true;

		$ret = true;
		foreach ( array_keys( $this->mc ) as $group )
			$ret &= $this->mc[$group]->flush();
		return $ret;
	}
}