WordPress/wp-includes/cache.php
Drew Jaynes 0860bb2771 Docs: Remove @access notations from method DocBlocks in wp-includes/* classes.
Prior to about 2013, many class methods lacked even access modifiers which made the `@access` notations that much more useful. Now that we've gotten to a point where the codebase is more mature from a maintenance perspective and we can finally remove these notations. Notable exceptions to this change include standalone functions notated as private as well as some classes still considered to represent "private" APIs.

See #41452.

Built from https://develop.svn.wordpress.org/trunk@41162


git-svn-id: http://core.svn.wordpress.org/trunk@41002 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2017-07-27 00:41:44 +00:00

733 lines
21 KiB
PHP

<?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. Disambiguates a return of false,
* a storable value. Passed by reference. 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. Disambiguates a return of
* false, a storable value. Passed by reference. 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;
}
}