代码学习之wordpress 的缓存处理类

<?php
class WP_Object_Cache {

	var $cache = array ();
	var $non_existent_objects = array ();
	var $cache_hits = 0;
	var $cache_misses = 0;
	var $global_groups = array();

	function add( $id, $data, $group = 'default', $expire = '' ) {
		if ( empty ($group) )
			$group = 'default';

		if (false !== $this->get($id, $group))
			return false;

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

	function add_global_groups( $groups ) {
		$groups = (array) $groups;

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

	function delete($id, $group = 'default', $force = false) {
		if (empty ($group))
			$group = 'default';

		if (!$force && false === $this->get($id, $group))
			return false;

		unset ($this->cache[$group][$id]);
		$this->non_existent_objects[$group][$id] = true;
		return true;
	}

	function flush() {
		$this->cache = array ();

		return true;
	}

	function get($id, $group = 'default') {
		if ( empty ($group) )
			$group = 'default';

		if ( isset ($this->cache[$group][$id]) ) {
			$this->cache_hits += 1;
			if ( is_object($this->cache[$group][$id]) )
				return wp_clone($this->cache[$group][$id]);
			else
				return $this->cache[$group][$id];
		}

		if ( isset ($this->non_existent_objects[$group][$id]) )
			return false;

		$this->non_existent_objects[$group][$id] = true;
		$this->cache_misses += 1;
		return false;
	}

	function replace($id, $data, $group = 'default', $expire = '') {
		if (empty ($group))
			$group = 'default';

		if ( false === $this->get($id, $group) )
			return false;

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


	function reset() {
		// Clear out non-global caches since the blog ID has changed.
		foreach ( array_keys($this->cache) as $group ) {
			if ( !in_array($group, $this->global_groups) )
				unset($this->cache[$group]);
		}
	}


	function set($id, $data, $group = 'default', $expire = '') {
		if ( empty ($group) )
			$group = 'default';

		if ( NULL === $data )
			$data = '';

		if ( is_object($data) )
			$data = wp_clone($data);

		$this->cache[$group][$id] = $data;

		if ( isset($this->non_existent_objects[$group][$id]) )
			unset ($this->non_existent_objects[$group][$id]);

		return true;
	}

	function stats() {
		echo "<p>";
		echo "<strong>Cache Hits:</strong> {$this->cache_hits}<br />";
		echo "<strong>Cache Misses:</strong> {$this->cache_misses}<br />";
		echo "</p>";

		foreach ($this->cache as $group => $cache) {
			echo "<p>";
			echo "<strong>Group:</strong> $group<br />";
			echo "<strong>Cache:</strong>";
			echo "<pre>";
			print_r($cache);
			echo "</pre>";
		}
	}

	function WP_Object_Cache() {
		return $this->__construct();
	}

	function __construct() {
		register_shutdown_function(array(&$this, "__destruct"));
	}

	function __destruct() {
		return true;
	}
}
?>

　　主要是学习缓存处理的思路，代码方面，其实个人用，就不必去向下兼容了