<?php
/**锁操作
 * Created by gzhq.
 * User: 252378189@qq.com
 * Date: 2018/3/18
 * Time: 20:18
 */
class gzhq_lock{
    const LOCK_TYPE_DB = 'SQLLock';
    const LOCK_TYPE_FILE = 'FileLock';
    const LOCK_TYPE_MEMCACHE = 'MemcacheLock';

    private $_lock = false;
    private static $_supportLocks = array('FileLock', 'SQLLock', 'MemcacheLock','RedisLock');

    public function __construct($type, $options = array()){
        if(false == empty($type)) {
            $this->createLock($type, $options);
        }
    }
    public function createLock($type, $options=array()){
        if(false == in_array($type, self::$_supportLocks)){
            throw new Exception("not support lock of ${type}");
        }else{
            $this->_lock = new $type($options);
        }
    }
    public function getLock($key, $timeout = in_lock::EXPIRE){
        if (false == $this->_lock instanceof in_lock) {
            throw new Exception('false == $this->_lock instanceof ILock');
        }
        $this->_lock->getLock($key, $timeout);
    }

    public function unLock($key){
        if (false == $this->_lock instanceof in_lock) {
            throw new Exception('false == $this->_lock instanceof ILock');
        }
        $this->_lock->unLock($key);
    }
}
//必须实现的接口
interface in_lock{
    const EXPIRE = 5;
    public function getLock($key, $timeout=self::EXPIRE);
    public function unLock($key);
}

//创建文件锁
class FileLock implements in_lock{
    private $_fp;
    private $_lockPath;
    //创建锁
    /*
    * $options = '';//文件存放路径
    */
    public function __construct($options){
        if (isset($options) && is_dir($options)) {
            $this->_lockPath = $options.'/';
        }else{
            $this->_lockPath = WEBPATH_DIR.'/cache/';
        }
    }
    public function getLock($key, $timeout=self::EXPIRE){
        $file = md5($key);
        $tmp_mypath = $this->_lockPath .$file.'.lock';
        $this->_fp = fopen($tmp_mypath,"w+");
        if ($this->_fp === false) {
            return false;
        }
        $waitime = 10;
        $totalWaitime = 0;
        $timeout *=1000000;
        while (!flock($this->_fp,LOCK_EX | LOCK_NB)) { // 加锁
            $totalWaitime +=$waitime;
            if ($totalWaitime > $timeout) { // 超时逻辑
                fclose($this->_fp);
                return false;
            }
            usleep($waitime);
        }
        return true;
    }
    public function unLock($key){
        flock($this->_fp,LOCK_UN);
        fclose($this->_fp);
        return true;
    }
}

//创建mysql锁
class SQLLock implements in_lock{
    private $_db;
    //创建锁
    /*
     * $options='';//数据库连接
     */
    public function __construct($options){
        $this->_db = $options;
    }

    public function getLock($key, $timeout=self::EXPIRE){
        $sql = "SELECT GET_LOCK('KEY".$key."', '".$timeout."')";
        $res = $this->_db->query($sql);
        return $res;
    }

    public function unLock($key){
        $sql = "SELECT RELEASE_LOCK('KEY".$key."')";
        return $this->_db->query($sql);
    }
}

//创建Memcache锁
class MemcacheLock implements in_lock{
    private $memcache;
    //创建锁
    /*
     * $options='';//Memcache连接
     */
    public function __construct($options){

        $this->memcache = $options;
    }
    public function getLock($key,$timeout=self::EXPIRE){
        $waitime = 10;
        $totalWaitime = 0;
        $time = $timeout*1000000;
        while (false == $this->memcache->add("KEY".$key, 1, $timeout)) {
            usleep($waitime);
            $totalWaitime += $waitime;
            if ($totalWaitime >= $time){
                return false;
            }
        }
        return true;
    }
    public function unLock($key){
        $this->memcache->delete("KEY".$key);
        return true;
    }
}
//创建redis锁
class RedisLock implements in_lock{
    private $redis;
    //创建锁
    /*
     * $options='';//Redis连接
     */
    public function __construct($options){
        $this->redis = $options;
    }
    public function getLock($key, $timeout=self::EXPIRE){
        $waitime = 10;//延时多久检查
        $totalWaitime = 0;//当前等了多久
        $time = $timeout*1000000;//把超时时间从毫秒改为微秒
        while(false==$this->redis->psetex("KEY".$key,$time,1)){
            usleep($waitime);
            $totalWaitime += $waitime;
            if ($totalWaitime >= $time){
                return false;
            }
        }
        return true;

    }
    public function unLock($key){
        $this->redis->delete("KEY".$key);
        return true;
    }
}