TP5.1 的
```
/**
* 读取缓存
* @access public
* @param string $name 缓存变量名
* @param mixed $default 默认值
* @return mixed
*/
public function get($name, $default = false)
{
$this->readTimes++;

$filename = $this->getCacheKey($name);

if (!is_file($filename)) {
return $default;
}

$content = file_get_contents($filename);
$this->expire = null;

if (false !== $content) {
$expire = (int) substr($content, 8, 12);
if (0 != $expire && time() > filemtime($filename) + $expire) {
//缓存过期删除缓存文件
$this->unlink($filename);
return $default;
}

$this->expire = $expire;
$content = substr($content, 32);

if ($this->options['data_compress'] && function_exists('gzcompress')) {
//启用数据压缩
$content = gzuncompress($content);
}
return $this->unserialize($content);
} else {
return $default;
}
}

/**
* 写入缓存
* @access public
* @param string $name 缓存变量名
* @param mixed $value 存储数据
* @param int|\DateTime $expire 有效时间 0 为永久
* @return boolean
*/
public function set($name, $value, $expire = null)
{
$this->writeTimes++;

if (is_null($expire)) {
$expire = $this->options['expire'];
}

$expire = $this->getExpireTime($expire);
$filename = $this->getCacheKey($name, true);

if ($this->tag && !is_file($filename)) {
$first = true;
}

$data = $this->serialize($value);

if ($this->options['data_compress'] && function_exists('gzcompress')) {
//数据压缩
$data = gzcompress($data, 3);
}

$data = "<?php\n//" . sprintf('%012d', $expire) . "\n exit();?>\n" . $data;
$result = file_put_contents($filename, $data);

if ($result) {
isset($first) && $this->setTagItem($filename);
clearstatcache();
return true;
} else {
return false;
}
}
```
也没加锁，会不会也有问题？