object-cache.php

<?php
/*
Plugin Name: Memcached Redux
Description: The real Memcached (not Memcache) backend for the WP Object Cache.
Version: 0.2.1
Plugin URI: https://github.com/Ipstenu/memcached-redux
Author: Scott Taylor - uses code from Ryan Boren, Denis de Bernardy, Matt Martz, Mike Schroder, Mika Epstein

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

if ( !defined( 'WP_CACHE_KEY_SALT' ) ) {
	define( 'WP_CACHE_KEY_SALT', '' );
}

if ( class_exists( 'Memcached' ) ):

	/**
	 * Determines whether the object cache implementation supports a particular feature.
	 *
	 * @param string $feature Name of the feature to check for. Possible values include:
	 *                        'add_multiple', 'set_multiple', 'get_multiple', 'delete_multiple',
	 *                        'flush_runtime', 'flush_group'.
	 *
	 * @return bool True if the feature is supported, false otherwise.
	 * @since 0.1.9
	 *
	 */
	function wp_cache_supports( $feature ) {
		switch ( $feature ) {
			case 'add_multiple':
			case 'set_multiple':
			case 'flush_runtime':
			case 'get_multiple':
			case 'delete_multiple':
				return true;

			default:
				return false;
		}
	}

	function wp_cache_add( $key, $data, $group = '', $expire = 0 ) {
		global $wp_object_cache;

		return $wp_object_cache->add( $key, $data, $group, $expire );
	}

	function wp_cache_add_multiple( array $data, $group = '', $expire = 0 ) {
		global $wp_object_cache;

		return $wp_object_cache->add_multiple( $data, $group, $expire );
	}

	function wp_cache_incr( $key, $n = 1, $group = '' ) {
		global $wp_object_cache;

		return $wp_object_cache->incr( $key, $n, $group );
	}

	function wp_cache_decr( $key, $n = 1, $group = '' ) {
		global $wp_object_cache;

		return $wp_object_cache->decr( $key, $n, $group );
	}

	function wp_cache_close() {
		global $wp_object_cache;

		return $wp_object_cache->close();
	}

	function wp_cache_delete( $key, $group = '' ) {
		global $wp_object_cache;

		return $wp_object_cache->delete( $key, $group );
	}

	function wp_cache_delete_multiple( array $keys, $group = '' ) {
		global $wp_object_cache;

		return $wp_object_cache->delete_multiple( $keys, $group );
	}

	function wp_cache_flush() {
		global $wp_object_cache;

		return $wp_object_cache->flush();
	}

	function wp_cache_get( $key, $group = '', $force = false, &$found = null ) {
		global $wp_object_cache;

		return $wp_object_cache->get( $key, $group, $force, $found );
	}

	function wp_cache_get_multiple( $keys, $group = '', $force = false ) {
		global $wp_object_cache;

		return $wp_object_cache->get_multiple( $keys, $group, $force );
	}

	/**
	 * $keys_and_groups = array(
	 *      array( 'key', 'group' ),
	 *      array( 'key', '' ),
	 *      array( 'key', 'group' ),
	 *      array( 'key' )
	 * );
	 */
	function wp_cache_get_multi( $key_and_groups, $bucket = 'default' ) {
		global $wp_object_cache;

		return $wp_object_cache->get_multi( $key_and_groups, $bucket );
	}

	function wp_cache_set_multiple( array $data, $group = '', $expire = 0 ) {
		global $wp_object_cache;

		return $wp_object_cache->set_multiple( $data, $group, $expire );
	}

	/**
	 * $items = array(
	 *      array( 'key', 'data', 'group' ),
	 *      array( 'key', 'data' )
	 * );
	 */
	function wp_cache_set_multi( $items, $expire = 0, $group = 'default' ) {
		global $wp_object_cache;

		return $wp_object_cache->set_multi( $items, $expire = 0, $group = 'default' );
	}

	function wp_cache_init() {
		global $wp_object_cache;

		$wp_object_cache = new WP_Object_Cache();
	}

	function wp_cache_replace( $key, $data, $group = '', $expire = 0 ) {
		global $wp_object_cache;

		return $wp_object_cache->replace( $key, $data, $group, $expire );
	}

	function wp_cache_set( $key, $data, $group = '', $expire = 0 ) {
		global $wp_object_cache;

		if ( defined( 'WP_INSTALLING' ) == false ) {
			return $wp_object_cache->set( $key, $data, $group, $expire );
		} else {
			return $wp_object_cache->delete( $key, $group );
		}
	}

	function wp_cache_add_global_groups( $groups ) {
		global $wp_object_cache;

		$wp_object_cache->add_global_groups( $groups );
	}

	function wp_cache_add_non_persistent_groups( $groups ) {
		global $wp_object_cache;

		$wp_object_cache->add_non_persistent_groups( $groups );
	}

	function wp_cache_flush_runtime() {
		global $wp_object_cache;

		return $wp_object_cache->flush_runtime();
	}


	class WP_Object_Cache {
		var $global_groups = array();

		var $no_mc_groups = array();

		var $cache = array();
		var $mc = array();
		var $default_mcs   = array();
		var $stats         = array(
			'get'          => 0,
			'get_local'    => 0,
			'get_multi'    => 0,
			'set'          => 0,
			'set_local'    => 0,
			'add'          => 0,
			'delete'       => 0,
			'delete_local' => 0,
			'slow-ops'     => 0,
		);
		var $group_ops     = array();
		var $cache_hits    = 0;
		var $cache_misses  = 0;
		var $global_prefix = '';
		var $blog_prefix   = '';
		var $key_salt      = '';

		var $flush_group         = 'WP_Object_Cache';
		var $global_flush_group  = 'WP_Object_Cache_global';
		var $flush_key           = "flush_number_v4";
		var $old_flush_key       = "flush_number";
		var $flush_number        = array();
		var $global_flush_number = null;

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

		var $time_start = 0;
		
		function add( $id, $data, $group = 'default', $expire = 0 ) {
			$key = $this->key( $id, $group );

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

			if ( in_array( $group, $this->no_mc_groups ) ) {
				$this->cache[ $key ] = $data;

				return true;
			} elseif ( isset( $this->cache[ $key ] ) && $this->cache[ $key ] !== false ) {
				return false;
			}

			$mc     =& $this->get_mc( $group );
			$expire = ( $expire == 0 ) ? $this->default_expiration : $expire;
			$result = $mc->add( $key, $data, $expire );

			if ( false !== $result ) {
				++ $this->stats['add'];
				$this->group_ops[ $group ][] = "add $id";
				$this->cache[ $key ]         = $data;
			}

			return $result;
		}

		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 );
		}

		public function add_multiple( array $data, $group = '', $expire = 0 ) {
			$values = array();

			foreach ( $data as $key => $value ) {
				$values[ $key ] = $this->add( $key, $value, $group, $expire );
			}

			return $values;
		}


		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 incr( $id, $n = 1, $group = 'default' ) {
			$key                 = $this->key( $id, $group );
			$mc                  =& $this->get_mc( $group );
			$this->cache[ $key ] = $mc->increment( $key, $n );

			return $this->cache[ $key ];
		}

		function decr( $id, $n = 1, $group = 'default' ) {
			$key                 = $this->key( $id, $group );
			$mc                  =& $this->get_mc( $group );
			$this->cache[ $key ] = $mc->decrement( $key, $n );

			return $this->cache[ $key ];
		}

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

		function flush_runtime() {
			$this->cache     = array();
			$this->group_ops = array();

			return true;
		}

		function delete( $id, $group = 'default' ) {
			$key = $this->key( $id, $group );

			if ( in_array( $group, $this->no_mc_groups ) ) {
				unset( $this->cache[ $key ] );

				return true;
			}

			$mc =& $this->get_mc( $group );

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

			if ( false !== $result ) {
				++ $this->stats['delete'];
				$this->group_ops[ $group ][] = "delete $id";
				unset( $this->cache[ $key ] );
			}

			return $result;
		}

		public function delete_multiple( array $keys, $group = '' ) {
			$values = array();

			foreach ( $keys as $key ) {
				$values[ $key ] = $this->delete( $key, $group );
			}

			return $values;
		}

		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;
		}

		function get( $id, $group = 'default', $force = false, &$found = null ) {
			$key   = $this->key( $id, $group );
			$mc    =& $this->get_mc( $group );
			$found = false;

			if ( isset( $this->cache[ $key ] ) && ( ! $force || in_array( $group, $this->no_mc_groups ) ) ) {
				$found = true;
				if ( is_object( $this->cache[ $key ] ) ) {
					$value = clone $this->cache[ $key ];
				} else {
					$value = $this->cache[ $key ];
				}
			} else if ( in_array( $group, $this->no_mc_groups ) ) {
				$this->cache[ $key ] = $value = false;
			} else {
				$value = $mc->get( $key );
				if ( empty( $value ) || ( is_integer( $value ) && - 1 == $value ) ) {
					$value = false;
					$found = $mc->getResultCode() !== Memcached::RES_NOTFOUND;
				} else {
					$found = true;
				}
				$this->cache[ $key ] = $value;
			}

			if ( $found ) {
				++ $this->stats['get'];
				$this->group_ops[ $group ][] = "get $id";
			} else {
				++ $this->stats['miss'];
			}

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

			return $value;
		}

		public function get_multiple( $keys, $group = 'default', $force = false) {
			$values = array();

			foreach ( $keys as $key ) {
				$values[ $key ] = $this->get( $key, $group, $force );
			}

			return $values;
		}

		function get_multi( $keys, $group = 'default' ) {
			$return = array();
			$gets   = array();
			foreach ( $keys as $i => $values ) {
				$mc     =& $this->get_mc( $group );
				$values = (array) $values;
				if ( empty( $values[1] ) ) {
					$values[1] = 'default';
				}

				list( $id, $group ) = (array) $values;
				$key = $this->key( $id, $group );

				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( $group, $this->no_mc_groups ) ) {
					$return[ $key ] = false;

				} else {
					$gets[ $key ] = $key;
				}
			}

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

			++ $this->stats['get_multi'];
			$this->group_ops[ $group ][] = "get_multi $id";
			$this->cache                 = array_merge( $this->cache, $return );

			return array_values( $return );
		}

		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 replace( $id, $data, $group = 'default', $expire = 0 ) {
			$key    = $this->key( $id, $group );
			$expire = ( $expire == 0 ) ? $this->default_expiration : $expire;
			$mc     =& $this->get_mc( $group );

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

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

			return $result;
		}

		function set( $id, $data, $group = 'default', $expire = 0 ) {
			$key = $this->key( $id, $group );
			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( $group, $this->no_mc_groups ) ) {
				return true;
			}

			$expire = ( $expire == 0 ) ? $this->default_expiration : $expire;
			$mc     =& $this->get_mc( $group );
			$result = $mc->set( $key, $data, $expire );

			return $result;
		}

		public function set_multiple( array $data, $group = '', $expire = 0 ) {
			$values = array();

			foreach ( $data as $key => $value ) {
				$values[ $key ] = $this->set( $key, $value, $group, $expire );
			}

			return $values;
		}

		function set_multi( $items, $expire = 0, $group = 'default' ) {
			$sets   = array();
			$mc     =& $this->get_mc( $group );
			$expire = ( $expire == 0 ) ? $this->default_expiration : $expire;

			foreach ( $items as $i => $item ) {
				if ( empty( $item[2] ) ) {
					$item[2] = 'default';
				}

				list( $id, $data, $group ) = $item;

				$key = $this->key( $id, $group );
				if ( isset( $this->cache[ $key ] ) && ( 'checkthedatabaseplease' === $this->cache[ $key ] ) ) {
					continue;
				}

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

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

				if ( in_array( $group, $this->no_mc_groups ) ) {
					continue;
				}

				$sets[ $key ] = $data;
			}

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

		function colorize_debug_line( $line ) {
			$colors = array(
				'get'    => 'green',
				'set'    => 'purple',
				'add'    => 'blue',
				'delete' => 'red'
			);

			$cmd = substr( $line, 0, strpos( $line, ' ' ) );

			$cmd2 = "<span style='color:" . esc_attr( $colors[ $cmd ] ) . "'>" . esc_html( $cmd ) . "</span>";

			return $cmd2 . esc_html( substr( $line, strlen( $cmd ) ) ) . "\n";
		}

		function stats() {
			echo "<p>\n";
			foreach ( $this->stats as $stat => $n ) {
				echo "<strong>" . esc_html( $stat ) . "</strong> " . esc_html( $n );
				echo "<br/>\n";
			}
			echo "</p>\n";
			echo "<h3>Memcached:</h3>";
			foreach ( $this->group_ops as $group => $ops ) {
				if ( ! isset( $_GET['debug_queries'] ) && 500 < count( $ops ) ) {
					$ops = array_slice( $ops, 0, 500 );
					echo "<big>Too many to show! <a href='" . esc_url( add_query_arg( 'debug_queries', 'true' ) ) . "'>Show them anyway</a>.</big>\n";
				}
				echo "<h4>" . esc_html( $group ) . " commands</h4>";
				echo "<pre>\n";
				$lines = array();
				foreach ( $ops as $op ) {
					$lines[] = $this->colorize_debug_line( $op );
				}
				print_r( $lines );
				echo "</pre>\n";
			}

			if ( ! empty( $this->debug ) && $this->debug ) {
				var_dump( $this->memcache_debug );
			}
		}

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

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

		function __construct() {

			$this->stats = array(
				'get'       => 0,
				'get_multi' => 0,
				'add'       => 0,
				'set'       => 0,
				'delete'    => 0,
				'miss'      => 0,
			);

			global $memcached_servers;

			if ( isset( $memcached_servers ) ) {
				$buckets = $memcached_servers;
			} else {
				$buckets = array( '127.0.0.1:11211' );
			}

			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 );
			}

			global $blog_id, $table_prefix;
			$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 ) . ':';
			}

			$this->cache_hits   =& $this->stats['get'];
			$this->cache_misses =& $this->stats['miss'];
		}
	}
else: // No Memcached

	// In 3.7+, we can handle this smoothly
	if ( function_exists( 'wp_using_ext_object_cache' ) ) {
		wp_using_ext_object_cache( false );

		// In earlier versions, there isn't a clean bail-out method.
	} else {
		wp_die( 'Memcached class not available.' );
	}

endif;