/**
* Returns cache engine instance
*
* @param string $engine
* @param array $config
* @return W3_Cache_Base
*/
function &instance($engine, $config = array())
{
static $instances = array();
$instance_key = sprintf('%s_%s', $engine, md5(serialize($config)));
if (!isset($instances[$instance_key])) {
switch ($engine) {
case W3_CACHE_MEMCACHED:
require_once W3TC_LIB_W3_DIR . '/Cache/Memcached.php';
$instances[$instance_key] =& W3_Cache_Memcached::instance($config['engine'], $config);
break;
case W3_CACHE_APC:
require_once W3TC_LIB_W3_DIR . '/Cache/Apc.php';
$instances[$instance_key] =& new W3_Cache_Apc();
break;
case W3_CACHE_FILE:
require_once W3TC_LIB_W3_DIR . '/Cache/File.php';
$instances[$instance_key] =& new W3_Cache_File($config);
break;
case W3_CACHE_FILE_PGCACHE:
require_once W3TC_LIB_W3_DIR . '/Cache/File/PgCache.php';
$instances[$instance_key] =& new W3_Cache_File_PgCache($config);
break;
default:
trigger_error('Incorrect cache engine', E_USER_WARNING);
require_once W3TC_LIB_W3_DIR . '/Cache/Base.php';
$instances[$instance_key] =& new W3_Cache_Base();
break;
}
}
return $instances[$instance_key];
}
/**
* Flushes cache
*/
function flush()
{
static $cache_path = null;
$cache =& $this->_get_cache();
if (is_a($cache, 'W3_Cache_Memcached') && class_exists('Memcache')) {
return $this->_memcached->flush();
} elseif (is_a($cache, 'Minify_Cache_APC') && function_exists('apc_clear_cache')) {
return apc_clear_cache('user');
} elseif (is_a($cache, 'Minify_Cache_File')) {
if (!is_dir(W3TC_CACHE_FILE_MINIFY_DIR)) {
$this->log(sprintf('Cache directory %s does not exists', W3TC_CACHE_FILE_MINIFY_DIR));
}
return w3_emptydir(W3TC_CACHE_FILE_MINIFY_DIR, array(W3TC_CACHE_FILE_MINIFY_DIR . '/index.php', W3TC_CACHE_FILE_MINIFY_DIR . '/.htaccess'));
}
return false;
}
/**
* Check if memcache is available
*
* @param array $servers
* @return boolean
*/
function is_memcache_available($servers)
{
static $results = array();
$key = md5(implode('', $servers));
if (!isset($results[$key])) {
w3_require_once(W3TC_LIB_W3_DIR . '/Cache/Memcached.php');
@($memcached = new W3_Cache_Memcached(array('servers' => $servers, 'persistant' => false)));
$test_string = sprintf('test_' . md5(time()));
$test_value = array('content' => $test_string);
$memcached->set($test_string, $test_value, 60);
$test_value = $memcached->get($test_string);
$results[$key] = $test_value['content'] == $test_string;
}
return $results[$key];
}
/**
* Returns minify cache object
*
* @return object
*/
function &_get_cache()
{
static $cache = array();
if (!isset($cache[0])) {
switch ($this->_config->get_string('minify.engine')) {
case 'memcached':
require_once W3TC_LIB_W3_DIR . '/Cache/Memcached.php';
require_once W3TC_LIB_MINIFY_DIR . '/Minify/Cache/Memcache.php';
$this->_memcached =& W3_Cache_Memcached::instance($this->_config->get_string('minify.memcached.engine'), array('servers' => $this->_config->get_array('minify.memcached.servers'), 'persistant' => true));
$cache[0] =& new Minify_Cache_Memcache($this->_memcached);
break;
case 'apc':
require_once W3TC_LIB_MINIFY_DIR . '/Minify/Cache/APC.php';
$cache[0] =& new Minify_Cache_APC();
break;
default:
require_once W3TC_LIB_MINIFY_DIR . '/Minify/Cache/File.php';
if (!is_dir(W3TC_CACHE_FILE_MINIFY_DIR)) {
$this->log(sprintf('Cache directory %s does not exist', W3TC_CACHE_FILE_MINIFY_DIR));
}
$cache[0] =& new Minify_Cache_File(W3TC_CACHE_FILE_MINIFY_DIR, $this->_config->get_boolean('minify.file.locking'));
break;
}
}
return $cache[0];
}