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<?php
/**
* Object Cache API
*
* @link https://codex.wordpress.org/Class_Reference/WP_Object_Cache
*
* @package WordPress
* @subpackage Cache
*/
/**
* Adds data to the cache, if the cache key doesn't already exist.
*
* @since 2.0.0
*
* @see WP_Object_Cache::add()
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*
* @param int|string $key The cache key to use for retrieval later.
* @param mixed $data The data to add to the cache.
* @param string $group Optional. The group to add the cache to. Enables the same key
* to be used across groups. Default empty.
* @param int $expire Optional. When the cache data should expire, in seconds.
* Default 0 (no expiration).
* @return bool False if cache key and group already exist, true on success.
*/
function wp_cache_add( $key, $data, $group = '', $expire = 0 ) {
global $wp_object_cache;
return $wp_object_cache->add( $key, $data, $group, (int) $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 true Always returns true.
*/
function wp_cache_close() {
return true;
}
/**
* Decrements numeric cache item's value.
*
* @since 3.3.0
*
* @see WP_Object_Cache::decr()
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*
* @param int|string $key The cache key to decrement.
* @param int $offset Optional. The amount by which to decrement the item's value. Default 1.
* @param string $group Optional. The group the key is in. Default empty.
* @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
*
* @see WP_Object_Cache::delete()
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*
* @param int|string $key What the contents in the cache are called.
* @param string $group Optional. Where the cache contents are grouped. Default empty.
* @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
*
* @see WP_Object_Cache::flush()
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*
* @return bool False on failure, true on success
*/
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
*
* @see WP_Object_Cache::get()
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*
* @param int|string $key The key under which the cache contents are stored.
* @param string $group Optional. Where the cache contents are grouped. Default empty.
* @param bool $force Optional. Whether to force an update of the local cache from the persistent
* cache. Default false.
* @param bool $found Optional. Whether the key was found in the cache (passed by reference).
* Disambiguates a return of false, a storable value. Default null.
* @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
*
* @see WP_Object_Cache::incr()
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*
* @param int|string $key The key for the cache contents that should be incremented.
* @param int $offset Optional. The amount by which to increment the item's value. Default 1.
* @param string $group Optional. The group the key is in. Default empty.
* @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
*/
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
*
* @see WP_Object_Cache::replace()
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*
* @param int|string $key The key for the cache data that should be replaced.
* @param mixed $data The new data to store in the cache.
* @param string $group Optional. The group for the cache data that should be replaced.
* Default empty.
* @param int $expire Optional. When to expire the cache contents, in seconds.
* Default 0 (no expiration).
* @return bool False if original value does not exist, true if contents were replaced
*/
function wp_cache_replace( $key, $data, $group = '', $expire = 0 ) {
global $wp_object_cache;
return $wp_object_cache->replace( $key, $data, $group, (int) $expire );
}
/**
* Saves the data to the cache.
*
* Differs from wp_cache_add() and wp_cache_replace() in that it will always write data.
*
* @since 2.0.0
*
* @see WP_Object_Cache::set()
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*
* @param int|string $key The cache key to use for retrieval later.
* @param mixed $data The contents to store in the cache.
* @param string $group Optional. Where to group the cache contents. Enables the same key
* to be used across groups. Default empty.
* @param int $expire Optional. When to expire the cache contents, in seconds.
* Default 0 (no expiration).
* @return bool False on failure, true on success
*/
function wp_cache_set( $key, $data, $group = '', $expire = 0 ) {
global $wp_object_cache;
return $wp_object_cache->set( $key, $data, $group, (int) $expire );
}
/**
* Switches the internal blog ID.
*
* This changes the blog id used to create keys in blog specific groups.
*
* @since 3.5.0
*
* @see WP_Object_Cache::switch_to_blog()
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*
* @param int $blog_id Site ID.
*/
function wp_cache_switch_to_blog( $blog_id ) {
global $wp_object_cache;
$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
*
* @see WP_Object_Cache::add_global_groups()
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*
* @param string|array $groups A group or an array of groups to add.
*/
function wp_cache_add_global_groups( $groups ) {
global $wp_object_cache;
$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.
}
/**
* Reset internal cache keys and structures.
*
* If the cache back end uses global blog or site IDs as part of its cache keys,
* this function instructs the back end 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 penalty for using it is
* high.
*
* @since 2.6.0
* @deprecated 3.5.0 WP_Object_Cache::reset()
* @see WP_Object_Cache::reset()
*
* @global WP_Object_Cache $wp_object_cache Object cache global instance.
*/
function wp_cache_reset() {
_deprecated_function( __FUNCTION__, '3.5.0', 'WP_Object_Cache::reset()' );
global $wp_object_cache;
$wp_object_cache->reset();
}
/**
* Core class that implements an 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.
*
* @since 2.0.0
*/
class WP_Object_Cache {
/**
* Holds the cached objects.
*
* @since 2.0.0
* @var array
*/
private $cache = array();
/**
* The amount of times the cache data was already stored in the cache.
*
* @since 2.5.0
* @var int
*/
public $cache_hits = 0;
/**
* Amount of times the cache did not have the request in cache.
*
* @since 2.0.0
* @var int
*/
public $cache_misses = 0;
/**
* List of global cache groups.
*
* @since 3.0.0
* @var array
*/
protected $global_groups = array();
/**
* The blog prefix to prepend to keys in non-global groups.
*
* @since 3.5.0
* @var int
*/
private $blog_prefix;
/**
* Holds the value of is_multisite().
*
* @since 3.5.0
* @var bool
*/
private $multisite;
/**
* Makes private properties readable for backward compatibility.
*
* @since 4.0.0
*
* @param string $name Property to get.
* @return mixed Property.
*/
public function __get( $name ) {
return $this->$name;
}
/**
* Makes private properties settable for backward compatibility.
*
* @since 4.0.0
*
* @param string $name Property to set.
* @param mixed $value Property value.
* @return mixed Newly-set property.
*/
public function __set( $name, $value ) {
return $this->$name = $value;
}
/**
* Makes private properties checkable for backward compatibility.
*
* @since 4.0.0
*
* @param string $name Property to check if set.
* @return bool Whether the property is set.
*/
public function __isset( $name ) {
return isset( $this->$name );
}
/**
* Makes private properties un-settable for backward compatibility.
*
* @since 4.0.0
*
* @param string $name Property to unset.
*/
public function __unset( $name ) {
unset( $this->$name );
}
/**
* Adds data to the cache if it doesn't already exist.
*
* @since 2.0.0
*
* @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.
*
* @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 Optional. Where to group the cache contents. Default 'default'.
* @param int $expire Optional. When to expire the cache contents. Default 0 (no expiration).
* @return bool False if cache key and group already exist, true on success
*/
public function add( $key, $data, $group = 'default', $expire = 0 ) {
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, (int) $expire );
}
/**
* Sets the list of global cache groups.
*
* @since 3.0.0
*
* @param array $groups List of groups that are global.
*/
public function add_global_groups( $groups ) {
$groups = (array) $groups;
$groups = array_fill_keys( $groups, true );
$this->global_groups = array_merge( $this->global_groups, $groups );
}
/**
* Decrements numeric cache item's value.
*
* @since 3.3.0
*
* @param int|string $key The cache key to decrement.
* @param int $offset Optional. The amount by which to decrement the item's value. Default 1.
* @param string $group Optional. The group the key is in. Default 'default'.
* @return false|int False on failure, the item's new value on success.
*/
public 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 ];
}
/**
* Removes the contents of the cache key in the group.
*
* If the cache key does not exist in the group, then nothing will happen.
*
* @since 2.0.0
*
* @param int|string $key What the contents in the cache are called.
* @param string $group Optional. Where the cache contents are grouped. Default 'default'.
* @param bool $deprecated Optional. Unused. Default false.
* @return bool False if the contents weren't deleted and true on success.
*/
public function delete( $key, $group = 'default', $deprecated = false ) {
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;
}
unset( $this->cache[ $group ][ $key ] );
return true;
}
/**
* Clears the object cache of all data.
*
* @since 2.0.0
*
* @return true Always returns true.
*/
public 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 Optional. Where the cache contents are grouped. Default 'default'.
* @param string $force Optional. Unused. Whether to force a refetch rather than relying on the local
* cache. Default false.
* @param bool $found Optional. Whether the key was found in the cache (passed by reference).
* Disambiguates a return of false, a storable value. Default null.
* @return false|mixed False on failure to retrieve contents or the cache contents on success.
*/
public function get( $key, $group = 'default', $force = false, &$found = null ) {
if ( empty( $group ) ) {
$group = 'default';
}
if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) ) {
$key = $this->blog_prefix . $key;
}
if ( $this->_exists( $key, $group ) ) {
$found = true;
$this->cache_hits += 1;
if ( is_object( $this->cache[ $group ][ $key ] ) ) {
return clone $this->cache[ $group ][ $key ];
} else {
return $this->cache[ $group ][ $key ];
}
}
$found = false;
$this->cache_misses += 1;
return false;
}
/**
* Increments numeric cache item's value.
*
* @since 3.3.0
*
* @param int|string $key The cache key to increment
* @param int $offset Optional. The amount by which to increment the item's value. Default 1.
* @param string $group Optional. The group the key is in. Default 'default'.
* @return false|int False on failure, the item's new value on success.
*/
public function incr( $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 ];
}
/**
* Replaces the contents in the cache, if contents already exist.
*
* @since 2.0.0
*
* @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 Optional. Where to group the cache contents. Default 'default'.
* @param int $expire Optional. When to expire the cache contents. Default 0 (no expiration).
* @return bool False if not exists, true if contents were replaced.
*/
public function replace( $key, $data, $group = 'default', $expire = 0 ) {
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, (int) $expire );
}
/**
* Resets cache keys.
*
* @since 3.0.0
*
* @deprecated 3.5.0 Use switch_to_blog()
* @see switch_to_blog()
*/
public function reset() {
_deprecated_function( __FUNCTION__, '3.5.0', 'switch_to_blog()' );
// Clear out non-global caches since the blog ID has changed.
foreach ( array_keys( $this->cache ) as $group ) {
if ( ! isset( $this->global_groups[ $group ] ) ) {
unset( $this->cache[ $group ] );
}
}
}
/**
* Sets the data contents into the cache.
*
* The cache contents is grouped by the $group parameter followed by the
* $key. This allows for duplicate ids in unique groups. Therefore, naming of
* the group should be used with care and should follow normal function
* naming guidelines outside of core WordPress usage.
*
* The $expire parameter is not used, because the cache will automatically
* expire for each time a page is accessed and PHP finishes. The method is
* more for cache plugins which use files.
*
* @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 Optional. Where to group the cache contents. Default 'default'.
* @param int $expire Not Used.
* @return true Always returns true.
*/
public function set( $key, $data, $group = 'default', $expire = 0 ) {
if ( empty( $group ) ) {
$group = 'default';
}
if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) ) {
$key = $this->blog_prefix . $key;
}
if ( is_object( $data ) ) {
$data = clone $data;
}
$this->cache[ $group ][ $key ] = $data;
return true;
}
/**
* Echoes the stats of the caching.
*
* Gives the cache hits, and cache misses. Also prints every cached group,
* key and the data.
*
* @since 2.0.0
*/
public function stats() {
echo '<p>';
echo "<strong>Cache Hits:</strong> {$this->cache_hits}<br />";
echo "<strong>Cache Misses:</strong> {$this->cache_misses}<br />";
echo '</p>';
echo '<ul>';
foreach ( $this->cache as $group => $cache ) {
echo "<li><strong>Group:</strong> $group - ( " . number_format( strlen( serialize( $cache ) ) / KB_IN_BYTES, 2 ) . 'k )</li>';
}
echo '</ul>';
}
/**
* Switches the internal 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.
*/
public function switch_to_blog( $blog_id ) {
$blog_id = (int) $blog_id;
$this->blog_prefix = $this->multisite ? $blog_id . ':' : '';
}
/**
* Serves as a utility function to determine whether a key exists in the cache.
*
* @since 3.4.0
*
* @param int|string $key Cache key to check for existence.
* @param string $group Cache group for the key existence check.
* @return bool Whether the key exists in the cache for the given group.
*/
protected function _exists( $key, $group ) {
return isset( $this->cache[ $group ] ) && ( isset( $this->cache[ $group ][ $key ] ) || array_key_exists( $key, $this->cache[ $group ] ) );
}
/**
* Sets up object properties; PHP 5 style constructor.
*
* @since 2.0.8
*/
public function __construct() {
$this->multisite = is_multisite();
$this->blog_prefix = $this->multisite ? get_current_blog_id() . ':' : '';
/**
* @todo This should be moved to the PHP4 style constructor, PHP5
* already calls __destruct()
*/
register_shutdown_function( array( $this, '__destruct' ) );
}
/**
* Saves the object cache before object is completely destroyed.
*
* Called upon object destruction, which should be when PHP ends.
*
* @since 2.0.8
*
* @return true Always returns true.
*/
public function __destruct() {
return true;
}
}