PHP进程锁

<?php/** * CacheLock 进程锁,主要用来进行cache失效时的单进程cache获取，防止过多的SQL请求穿透到数据库 * 用于解决PHP在并发时候的锁控制,通过文件/eaccelerator进行进程间锁定 * 如果没有使用eaccelerator则进行进行文件锁处理，会做对应目录下产生对应粒度的锁 * 使用了eaccelerator则在内存中处理，性能相对较高 * 不同的锁之间并行执行，类似mysql innodb的行级锁 * 本类在sunli的phplock的基础上做了少许修改 ?http://code.google.com/p/phplock * @author yangxinqi * */namespace Common\Business; ?class PhpLock{ ???//文件锁存放路径 ???private $path = null; ???//文件句柄 ???private $fp = null; ???//锁粒度,设置越大粒度越小 ???private $hashNum = 100; ???//cache key ???private $name; ???//是否存在eaccelerator标志 ???private ?$eAccelerator = false; ????/** ????* 构造函数 ????* 传入锁的存放路径，及cache key的名称，这样可以进行并发 ????* @param string $path 锁的存放目录，以"/"结尾 ????* @param string $name cache key ????*/ ???public function __construct($name,$path=‘lock\\‘) ???{ ???????$app_path = str_replace(‘ThinkPHP/‘, ‘‘, THINK_PATH); ???????$is_cli = php_sapi_name(); ???????if($is_cli == ‘cli‘ || $is_cli == ‘cli_server‘) ???????{ ???????????$app_path = trim(APP_PATH, ‘.‘); ???????} ???????else ???????{ ???????????$app_path = $app_path . trim(APP_PATH, ‘.‘); ???????} ????????$path = $app_path.‘/Common/Business/lockfile/‘; ???????if(!file_exists($path)) ???????{ ???????????mkdir($path); ???????????chmod($path,777); ???????} ???????//$path .= ‘/protected/runtime/cache/‘; ???????//判断是否存在eAccelerator,这里启用了eAccelerator之后可以进行内存锁提高效率 ???????$this->eAccelerator = function_exists("eaccelerator_lock"); ???????if(!$this->eAccelerator) ???????{ ???????????//$this->path = $path.($this->_mycrc32($name) % $this->hashNum).‘.txt‘; ???????????$this->path = $path.sha1($name).‘.txt‘; ???????} ???????$this->name = $name; ???} ????/** * crc32 * crc32封装 * @param int $string * @return int */ ???private function _mycrc32($string) ???{ ???????$crc = abs (crc32($string)); ???????if ($crc & 0x80000000) { ???????????$crc ^= 0xffffffff; ???????????$crc += 1; ???????} ???????return $crc; ???} ???/** ????* 加锁 ????* Enter description here ... ????*/ ???public function lock() ???{ ???????//如果无法开启ea内存锁，则开启文件锁 ???????if(!$this->eAccelerator) ???????{ ???????????//配置目录权限可写 ???????????$this->fp = fopen($this->path, ‘w+‘); ???????????if($this->fp === false) ???????????{ ???????????????return false; ???????????} ???????????return flock($this->fp, LOCK_EX); ???????}else{ ???????????return eaccelerator_lock($this->name); ???????} ???} ????/** ????* 解锁 ????* Enter description here ... ????*/ ???public function unlock() ???{ ???????if(!$this->eAccelerator) ???????{ ???????????if($this->fp !== false) ???????????{ ???????????????flock($this->fp, LOCK_UN); ???????????????clearstatcache(); ???????????} ???????????//进行关闭 ???????????fclose($this->fp); ???????}else{ ???????????return eaccelerator_unlock($this->name); ???????} ???}}