PHP 缓存实现代码及详细注释

if (!$expire) {
$expire = $this->_expire;
}

$this->_storage->checkLock($key);

$data = array('time' => time(), 'expire' => $expire, 'valid' => true, 'data' => $value);
$this->_storage->lock($key);

try {
$this->_storage->store($key, $data);
$this->_storage->unlock($key);
} catch (CacheException $e) {
$this->_storage->unlock($key);
throw $e;
}
}
/**
* 读取缓存
*
* @param string $key
* @return mixed
*/
public function get($key) {
$data = $this->fetch($key);
if ($data && $data['valid'] && !$data['isExpired']) {
return $data['data'];
}

return false;
}
/**
* 读缓存，包括过期的和无效的，取得完整的存贮结构
*
* @param string $key
*/
public function fetch($key) {
$this->_storage->checkLock($key);
$data = $this->_storage->fetch($key);
if ($data) {
$data['isExpired'] = (time() - $data['time']) > $data['expire'] ? true : false;
return $data;
}

return false;
}
/**
* 删除缓存
*
* @param string $key
*/
public function delete($key) {
$this->_storage->checkLock($key)
->lock($key)
->delete($key)
->unlock($key);
}

public function clear() {
$this->_storage->clear();
}
/**
* 把缓存设为无效
*
* @param string $key
*/
public function setInvalidate($key) {
$this->_storage->checkLock($key)
->lock($key);
try {
$data = $this->_storage->fetch($key);
if ($data) {
$data['valid'] = false;
$this->_storage->store($key, $data);
}
$this->_storage->unlock($key);
} catch (CacheException $e) {
$this->_storage->unlock($key);
throw $e;
}
}

/**
* 设置缓存过期时间（s）
*
* @param int $expire
*/
public function setExpire($expire) {
$this->_expire = (int) $expire;
return $this;
}
}