<?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 );

	}

	/**

	 * 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 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 );

	}

	/**

	 * 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 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 ];

	}

	/**

	 * 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   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 values organized into groups.

	 */

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

		$values = array();

		foreach ( $keys as $key ) {

			$values[ $key ] = $this->get( $key, $group, $force );

		}

		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 ];

	}

	/**

	 * 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 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 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;