<?php
/**
* Object Cache API: WP_Object_Cache class
*
* @package WordPress
* @subpackage Cache
* @since 5.4.0
*/
/**
* 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 string
*/
private $blog_prefix;
/**
* Holds the value of is_multisite().
*
* @since 3.5.0
* @var bool
*/
private $multisite;
/**
* 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() . ':' : '';
}
/**
* 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 );
}
/**
* 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 ] ) );
}
/**
* 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, in seconds.
* Default 0 (no expiration).
* @return bool True on success, false if cache key and group already exist.
*/
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 );
}
/**
* Adds multiple values to the cache in one call.
*
* @since 6.0.0
*
* @param array $data Array of keys and values to be added.
* @param string $group Optional. Where the cache contents are grouped. Default empty.
* @param int $expire Optional. When to expire the cache contents, in seconds.
* Default 0 (no expiration).
* @return bool[] Array of return values, grouped by key. Each value is either
* true on success, or false if cache key and group already exist.
*/
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;
}
/**
* 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, in seconds.
* Default 0 (no expiration).
* @return bool True if contents were replaced, false if original value does not exist.
*/
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 );
}
/**
* Sets the data contents into the cache.
*
* The cache contents are 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 Optional. 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;
}
/**
* Sets multiple values to the cache in one call.
*
* @since 6.0.0
*
* @param array $data Array of key and value to be set.
* @param string $group Optional. Where the cache contents are grouped. Default empty.
* @param int $expire Optional. When to expire the cache contents, in seconds.
* Default 0 (no expiration).
* @return bool[] Array of return values, grouped by key. Each value is always true.
*/
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;
}
/**
* 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 The key under which the cache contents are stored.
* @param string $group Optional. Where the cache contents are grouped. Default 'default'.
* @param bool $force Optional. Unused. 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 mixed|false The cache contents on success, false on failure to retrieve contents.
*/
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;
}
/**
* Retrieves multiple values from the cache in one call.
*
* @since 5.5.0
*
* @param array $keys Array of keys under which the cache contents are stored.
* @param string $group Optional. Where the cache contents are grouped. Default 'default'.
* @param bool $force Optional. Whether to force an update of the local cache
* from the persistent cache. Default false.
* @return array Array of return values, grouped by key. Each value is either
* the cache contents on success, or false on failure.
*/
public function get_multiple( $keys, $group = 'default', $force = false ) {
$values = array();
foreach ( $keys as $key ) {
$values[ $key ] = $this->get( $key, $group, $force );
}
return $values;
}
/**
* 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 True on success, false if the contents were not deleted.
*/
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;
}
/**
* Deletes multiple values from the cache in one call.
*
* @since 6.0.0
*
* @param array $keys Array of keys to be deleted.
* @param string $group Optional. Where the cache contents are grouped. Default empty.
* @return bool[] Array of return values, grouped by key. Each value is either
* true on success, or false if the contents were not deleted.
*/
public function delete_multiple( array $keys, $group = '' ) {
$values = array();
foreach ( $keys as $key ) {
$values[ $key ] = $this->delete( $key, $group );
}
return $values;
}
/**
* 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 int|false The item's new value on success, false on failure.
*/
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 ];
}
/**
* 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 int|false The item's new value on success, false on failure.
*/
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 ];
}
/**
* Clears the object cache of all data.
*
* @since 2.0.0
*
* @return true Always returns true.
*/
public function flush() {
$this->cache = array();
return true;
}
/**
* Sets the list of global cache groups.
*
* @since 3.0.0
*
* @param string|string[] $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 );
}
/**
* 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 . ':' : '';
}
/**
* Resets cache keys.
*
* @since 3.0.0
*
* @deprecated 3.5.0 Use WP_Object_Cache::switch_to_blog()
* @see switch_to_blog()
*/
public function reset() {
_deprecated_function( __FUNCTION__, '3.5.0', 'WP_Object_Cache::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[ $group ] );
}
}
}
/**
* Echoes the stats of the caching.
*
* Gives the cache hits, and cache misses. Also prints every cached group,
* key and the data.
*
* @since 2.0.0
*/
public function stats() {
echo '<p>';
echo "<strong>Cache Hits:</strong> {$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> ' . esc_html( $group ) . ' - ( ' . number_format( strlen( serialize( $cache ) ) / KB_IN_BYTES, 2 ) . 'k )</li>';
}
echo '</ul>';
}
}