<?php

/**

 * Object Cache API

 *

 * @link http://codex.wordpress.org/Function_Reference/WP_Cache

 *

 * @package WordPress

 * @subpackage Cache

 */

/**

 * Adds data to the cache, if the cache key doesn't already exist.

 *

 * @since 2.0.0

 * @uses $wp_object_cache Object Cache Class

 * @see WP_Object_Cache::add()

 *

 * @param int|string $key The cache key to use for retrieval later

 * @param mixed $data The data to add to the cache store

 * @param string $group The group to add the cache to

 * @param int $expire When the cache data should be expired

 * @return unknown

 */

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

	global $wp_object_cache;

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

}

/**

 * Closes the cache.

 *

 * This function has ceased to do anything since WordPress 2.5. The

 * functionality was removed along with the rest of the persistent cache. This

 * does not mean that plugins can't implement this function when they need to

 * make sure that the cache is cleaned up after WordPress no longer needs it.

 *

 * @since 2.0.0

 *

 * @return bool Always returns True

 */

function wp_cache_close() {

	return true;

}

/**

 * Decrement numeric cache item's value

 *

 * @since 3.3.0

 * @uses $wp_object_cache Object Cache Class

 * @see WP_Object_Cache::decr()

 *

 * @param int|string $key The cache key to increment

 * @param int $offset The amount by which to decrement the item's value. Default is 1.

 * @param string $group The group the key is in.

 * @return false|int False on failure, the item's new value on success.

 */

function wp_cache_decr( $key, $offset = 1, $group = '' ) {

	global $wp_object_cache;

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

}

/**

 * Removes the cache contents matching key and group.

 *

 * @since 2.0.0

 * @uses $wp_object_cache Object Cache Class

 * @see WP_Object_Cache::delete()

 *

 * @param int|string $key What the contents in the cache are called

 * @param string $group Where the cache contents are grouped

 * @return bool True on successful removal, false on failure

 */

function wp_cache_delete($key, $group = '') {

	global $wp_object_cache;

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

}

/**

 * Removes all cache items.

 *

 * @since 2.0.0

 * @uses $wp_object_cache Object Cache Class

 * @see WP_Object_Cache::flush()

 *

 * @return bool Always returns true

 */

function wp_cache_flush() {

	global $wp_object_cache;

	return $wp_object_cache->flush();

}

/**

 * Retrieves the cache contents from the cache by key and group.

 *

 * @since 2.0.0

 * @uses $wp_object_cache Object Cache Class

 * @see WP_Object_Cache::get()

 *

 * @param int|string $key What the contents in the cache are called

 * @param string $group Where the cache contents are grouped

 * @param bool $force Whether to force an update of the local cache from the persistent cache (default is false)

 * @param &bool $found Whether key was found in the cache. Disambiguates a return of false, a storable value.

 * @return bool|mixed False on failure to retrieve contents or the cache

 *		contents on success

 */

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

	global $wp_object_cache;

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

}

/**

 * Increment numeric cache item's value

 *

 * @since 3.3.0

 * @uses $wp_object_cache Object Cache Class

 * @see WP_Object_Cache::incr()

 *

 * @param int|string $key The cache key to increment

 * @param int $offset The amount by which to increment the item's value. Default is 1.

 * @param string $group The group the key is in.

 * @return false|int False on failure, the item's new value on success.

 */

function wp_cache_incr( $key, $offset = 1, $group = '' ) {

	global $wp_object_cache;

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

}

/**

 * Sets up Object Cache Global and assigns it.

 *

 * @since 2.0.0

 * @global WP_Object_Cache $wp_object_cache WordPress Object Cache

 */

function wp_cache_init() {

	$GLOBALS['wp_object_cache'] = new WP_Object_Cache();

}

/**

 * Replaces the contents of the cache with new data.

 *

 * @since 2.0.0

 * @uses $wp_object_cache Object Cache Class

 * @see WP_Object_Cache::replace()

 *

 * @param int|string $key What to call the contents in the cache

 * @param mixed $data The contents to store in the cache

 * @param string $group Where to group the cache contents

 * @param int $expire When to expire the cache contents

 * @return bool False if cache key and group already exist, true on success

 */

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

	global $wp_object_cache;

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

}

/**

 * Saves the data to the cache.

 *

 * @since 2.0

 * @uses $wp_object_cache Object Cache Class

 * @see WP_Object_Cache::set()

 *

 * @param int|string $key What to call the contents in the cache

 * @param mixed $data The contents to store in the cache

 * @param string $group Where to group the cache contents

 * @param int $expire When to expire the cache contents

 * @return bool False if cache key and group already exist, true on success

 */

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

	global $wp_object_cache;

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

}

/**

 * Switch the interal blog id.

 *

 * This changes the blog id used to create keys in blog specific groups.

 *

 * @since 3.5.0

 *

 * @param int $blog_id Blog ID

 */

function wp_cache_switch_to_blog( $blog_id ) {

	global $wp_object_cache;

	return $wp_object_cache->switch_to_blog( $blog_id );

}

/**

 * Adds a group or set of groups to the list of global groups.

 *

 * @since 2.6.0

 *

 * @param string|array $groups A group or an array of groups to add

 */

function wp_cache_add_global_groups( $groups ) {

	global $wp_object_cache;

	return $wp_object_cache->add_global_groups( $groups );

}

/**

 * Adds a group or set of groups to the list of non-persistent groups.

 *

 * @since 2.6.0

 *

 * @param string|array $groups A group or an array of groups to add

 */

function wp_cache_add_non_persistent_groups( $groups ) {

	// Default cache doesn't persist so nothing to do here.

	return;

}

/**

 * Reset internal cache keys and structures. If the cache backend uses global

 * blog or site IDs as part of its cache keys, this function instructs the

 * backend to reset those keys and perform any cleanup since blog or site IDs

 * have changed since cache init.

 *

 * This function is deprecated. Use wp_cache_switch_to_blog() instead of this

 * function when preparing the cache for a blog switch. For clearing the cache

 * during unit tests, consider using wp_cache_init(). wp_cache_init() is not

 * recommended outside of unit tests as the performance penality for using it is

 * high.

 *

 * @since 2.6.0

 * @deprecated 3.5.0

 */

function wp_cache_reset() {

	_deprecated_function( __FUNCTION__, '3.5' );

	global $wp_object_cache;

	return $wp_object_cache->reset();

}

/**

 * WordPress Object Cache

 *

 * The WordPress Object Cache is used to save on trips to the database. The

 * Object Cache stores all of the cache data to memory and makes the cache

 * contents available by using a key, which is used to name and later retrieve

 * the cache contents.

 *

 * The Object Cache can be replaced by other caching mechanisms by placing files

 * in the wp-content folder which is looked at in wp-settings. If that file

 * exists, then this file will not be included.

 *

 * @package WordPress

 * @subpackage Cache

 * @since 2.0

 */

class WP_Object_Cache {

	/**

	 * Holds the cached objects

	 *

	 * @var array

	 * @access private

	 * @since 2.0.0

	 */

	var $cache = array ();

	/**

	 * The amount of times the cache data was already stored in the cache.

	 *

	 * @since 2.5.0

	 * @access private

	 * @var int

	 */

	var $cache_hits = 0;

	/**

	 * Amount of times the cache did not have the request in cache

	 *

	 * @var int

	 * @access public

	 * @since 2.0.0

	 */

	var $cache_misses = 0;

	/**

	 * List of global groups

	 *

	 * @var array

	 * @access protected

	 * @since 3.0.0

	 */

	var $global_groups = array();

	/**

	 * The blog prefix to prepend to keys in non-global groups.

	 *

	 * @var int

	 * @access private

	 * @since 3.5.0

	 */

	var $blog_prefix;

	/**

	 * Adds data to the cache if it doesn't already exist.

	 *

	 * @uses WP_Object_Cache::_exists Checks to see if the cache already has data.

	 * @uses WP_Object_Cache::set Sets the data after the checking the cache

	 *		contents existence.

	 *

	 * @since 2.0.0

	 *

	 * @param int|string $key What to call the contents in the cache

	 * @param mixed $data The contents to store in the cache

	 * @param string $group Where to group the cache contents

	 * @param int $expire When to expire the cache contents

	 * @return bool False if cache key and group already exist, true on success

	 */

	function add( $key, $data, $group = 'default', $expire = '' ) {

		if ( wp_suspend_cache_addition() )

			return false;

		if ( empty( $group ) )

			$group = 'default';

		$id = $key;

		if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) )

			$id = $this->blog_prefix . $key;

		if ( $this->_exists( $id, $group ) )

			return false;

		return $this->set($key, $data, $group, $expire);

	}

	/**

	 * Sets the list of global groups.

	 *

	 * @since 3.0.0

	 *

	 * @param array $groups List of groups that are global.

	 */

	function add_global_groups( $groups ) {

		$groups = (array) $groups;

		$groups = array_fill_keys( $groups, true );

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

	}

	/**

	 * Decrement numeric cache item's value

	 *

	 * @since 3.3.0

	 *

	 * @param int|string $key The cache key to increment

	 * @param int $offset The amount by which to decrement the item's value. Default is 1.

	 * @param string $group The group the key is in.

	 * @return false|int False on failure, the item's new value on success.

	 */

	function decr( $key, $offset = 1, $group = 'default' ) {

		if ( empty( $group ) )

			$group = 'default';

		if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) )

			$key = $this->blog_prefix . $key;

		if ( ! $this->_exists( $key, $group ) )

			return false;

		if ( ! is_numeric( $this->cache[ $group ][ $key ] ) )

			$this->cache[ $group ][ $key ] = 0;

		$offset = (int) $offset;

		$this->cache[ $group ][ $key ] -= $offset;

		if ( $this->cache[ $group ][ $key ] < 0 )

			$this->cache[ $group ][ $key ] = 0;

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

	}

	/**

	 * Remove the contents of the cache key in the group

	 *

	 * If the cache key does not exist in the group and $force parameter is set

	 * to false, then nothing will happen. The $force parameter is set to false

	 * by default.

	 *

	 * @since 2.0.0

	 *

	 * @param int|string $key What the contents in the cache are called

	 * @param string $group Where the cache contents are grouped

	 * @param bool $force Optional. Whether to force the unsetting of the cache

	 *		key in the group

	 * @return bool False if the contents weren't deleted and true on success

	 */

	function delete($key, $group = 'default', $force = false) {

		if ( empty( $group ) )

			$group = 'default';

		if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) )

			$key = $this->blog_prefix . $key;

		if ( ! $force && ! $this->_exists( $key, $group ) )

			return false;

		unset( $this->cache[$group][$key] );

		return true;

	}

	/**

	 * Clears the object cache of all data

	 *

	 * @since 2.0.0

	 *

	 * @return bool Always returns true

	 */

	function flush() {

		$this->cache = array ();

		return true;

	}

	/**

	 * Retrieves the cache contents, if it exists

	 *

	 * The contents will be first attempted to be retrieved by searching by the

	 * key in the cache group. If the cache is hit (success) then the contents

	 * are returned.

	 *

	 * On failure, the number of cache misses will be incremented.

	 *

	 * @since 2.0.0

	 *

	 * @param int|string $key What the contents in the cache are called

	 * @param string $group Where the cache contents are grouped

	 * @param string $force Whether to force a refetch rather than relying on the local cache (default is false)

	 * @return bool|mixed False on failure to retrieve contents or the cache