Viewing file:  Memcache.php (5.24 KB) -rw-rw-rw-
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<?php
/**
* Class Minify_Cache_Memcache
* @package Minify
*/
/**
* Memcache-based cache class for Minify
*
* <code>
* // fall back to disk caching if memcache can't connect
* $memcache = new Memcache;
* if ($memcache->connect('localhost', 11211)) {
* Minify::setCache(new Minify_Cache_Memcache($memcache));
* } else {
* Minify::setCache();
* }
* </code>
**/
class Minify_Cache_Memcache {
/*
* Blog id
*
* @var integer
*/
private $_blog_id = 0;
/**
* Used for faster flushing
*
* @var integer $_key_postfix
*/
private $_key_version = 0;
/**
* @var int current wp instance id
*/
private $_instance_id = 0;
/**
* Create a Minify_Cache_Memcache object, to be passed to
* Minify::setCache().
*
* @param Memcache $memcache already-connected instance
*
* @param int $expire seconds until expiration (default = 0
* meaning the item will not get an expiration date)
*
* @param int $blog_id
* @param int $instance_id current wp instance
*/
public function __construct($memcache, $expire = 0, $blog_id = 0, $instance_id = 0) {
$this->_mc = $memcache;
$this->_exp = $expire;
$this->_blog_id = $blog_id;
$this->_instance_id = $instance_id;
}
/**
* Write data to cache.
*
* @param string $id cache id
*
* @param string $data
*
* @return bool success
*/
public function store($id, $data) {
$v['key_version'] = $this->_get_key_version();
$v['content'] = "{$_SERVER['REQUEST_TIME']}|{$data}";
return $this->_mc->set($id . '_' . $this->_blog_id, $v, 0, $this->_exp);
}
/**
* Get the size of a cache entry
*
* @param string $id cache id
*
* @return int size in bytes
*/
public function getSize($id) {
return $this->_fetch($id)
? strlen($this->_data)
: false;
}
/**
* Does a valid cache entry exist?
*
* @param string $id cache id
*
* @param int $srcMtime mtime of the original source file(s)
*
* @return bool exists
*/
public function isValid($id, $srcMtime) {
return ($this->_fetch($id) && ($this->_lm >= $srcMtime));
}
/**
* Send the cached content to output
*
* @param string $id cache id
*/
public function display($id) {
echo $this->_fetch($id)
? $this->_data
: '';
}
/**
* Fetch the cached content
*
* @param string $id cache id
*
* @return string
*/
public function fetch($id) {
return $this->_fetch($id)
? $this->_data
: '';
}
private $_mc = null;
private $_exp = null;
// cache of most recently fetched id
private $_lm = null;
private $_data = null;
private $_id = null;
/**
* Fetch data and timestamp from memcache, store in instance
*
* @param string $id
*
* @return bool success
*/
private function _fetch($id) {
if ($this->_id === $id) {
return true;
}
$v = $this->_mc->get($id . '_' . $this->_blog_id);
if (!is_array($v)) {
$this->_id = null;
return false;
}
$key_version = $this->_get_key_version();
if ($v['key_version'] == $key_version){
list($this->_lm, $this->_data) = explode('|', $v['content'], 2);
$this->_id = $id;
return true;
}
if ($v['key_version'] > $key_version) {
$this->_set_key_version($v['key_version']);
list($this->_lm, $this->_data) = explode('|', $v['content'], 2);
$this->_id = $id;
return true;
}
// if we have expired data - update it for future use and let
// current process recalculate it
$expires_at = isset($v['expires_at']) ? $v['expires_at'] : null;
if ($expires_at == null || time() > $expires_at) {
$v['expires_at'] = time() + 30;
$this->_mc->set($id . '_' . $this->_blog_id, $v, false, 0);
$this->_id = null;
return false;
}
}
/**
* Flushes all data
*
* @return boolean
*/
function flush() {
$this->_get_key_version(); // initialize $this->_key_postfix
$this->_key_version++;
$this->_set_key_version($this->_key_version);
return true;
}
/**
* Returns key version
*
* @return integer
*/
private function _get_key_version() {
if ($this->_key_version <= 0) {
$v = @$this->_mc->get($this->_get_key_version_key());
$v = intval($v);
$this->_key_version = ($v > 0 ? $v : 1);
}
return $this->_key_version;
}
/**
* Sets new key version
* @param $v
* @return boolean
*/
private function _set_key_version($v) {
@$this->_mc->set($this->_get_key_version_key(), $v, false, 0);
}
/**
* Constructs key version key
* @return string
*/
private function _get_key_version_key() {
return sprintf('w3tc_%d_%s_%d_key_version', $this->_blog_id, 'minify', $this->_instance_id);
}
}
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