php自己实现memcached的队列类

add('1asdf'); *      $obj->getQueueLength(); *      $obj->read(11); *      $obj->get(8); */class memcacheQueue{    public static   $client;            //memcache客户端连接    public          $access;            //队列是否可更新       private         $currentSide;       //当前轮值的队列面:A/B    private         $lastSide;          //上一轮值的队列面:A/B    private         $sideAHead;         //A面队首值    private         $sideATail;         //A面队尾值    private         $sideBHead;         //B面队首值    private         $sideBTail;         //B面队尾值    private         $currentHead;       //当前队首值    private         $currentTail;       //当前队尾值    private         $lastHead;          //上轮队首值    private         $lastTail;          //上轮队尾值     private         $expire;            //过期时间,秒,1~2592000,即30天内;0为永不过期    private         $sleepTime;         //等待解锁时间,微秒    private         $queueName;         //队列名称,唯一值    private         $retryNum;          //重试次数,= 10 * 理论并发数    const   MAXNUM      = 2000;                 //(单面)最大队列数,建议上限10K    const   HEAD_KEY    = '_lkkQueueHead_';     //队列首kye    const   TAIL_KEY    = '_lkkQueueTail_';     //队列尾key    const   VALU_KEY    = '_lkkQueueValu_';     //队列值key    const   LOCK_KEY    = '_lkkQueueLock_';     //队列锁key    const   SIDE_KEY    = '_lkkQueueSide_';     //轮值面key    /*     * 构造函数     * @param   [config]    array   memcache服务器参数     * @param   [queueName] string  队列名称     * @param   [expire]    string  过期时间     * @return  NULL     */    public function __construct($queueName ='',$expire='',$config =''){        if(empty($config)){            self::$client = memcache_pconnect('localhost',11211);        }elseif(is_array($config)){//array('host'=>'127.0.0.1','port'=>'11211')            self::$client = memcache_pconnect($config['host'],$config['port']);        }elseif(is_string($config)){//"127.0.0.1:11211"            $tmp = explode(':',$config);            $conf['host'] = isset($tmp[0]) ? $tmp[0] : '127.0.0.1';            $conf['port'] = isset($tmp[1]) ? $tmp[1] : '11211';            self::$client = memcache_pconnect($conf['host'],$conf['port']);             }        if(!self::$client) return false;        ignore_user_abort(TRUE);//当客户断开连接,允许继续执行        set_time_limit(0);//取消脚本执行延时上限        $this->access = false;        $this->sleepTime = 1000;        $expire = (empty($expire) && $expire!=0) ? 3600 : (int)$expire;        $this->expire = $expire;        $this->queueName = $queueName;        $this->retryNum = 10000;        $side = memcache_add(self::$client, $queueName . self::SIDE_KEY, 'A',false, $expire);        $this->getHeadNTail($queueName);        if(!isset($this->sideAHead) || empty($this->sideAHead)) $this->sideAHead = 0;        if(!isset($this->sideATail) || empty($this->sideATail)) $this->sideATail = 0;        if(!isset($this->sideBHead) || empty($this->sideBHead)) $this->sideBHead = 0;        if(!isset($this->sideBHead) || empty($this->sideBHead)) $this->sideBHead = 0;    }    /*     * 获取队列首尾值     * @param   [queueName] string  队列名称     * @return  NULL     */    private function getHeadNTail($queueName){        $this->sideAHead = (int)memcache_get(self::$client, $queueName.'A'. self::HEAD_KEY);        $this->sideATail = (int)memcache_get(self::$client, $queueName.'A'. self::TAIL_KEY);        $this->sideBHead = (int)memcache_get(self::$client, $queueName.'B'. self::HEAD_KEY);        $this->sideBTail = (int)memcache_get(self::$client, $queueName.'B'. self::TAIL_KEY);    }    /*     * 获取当前轮值的队列面     * @return  string  队列面名称     */    public function getCurrentSide(){        $currentSide = memcache_get(self::$client, $this->queueName . self::SIDE_KEY);        if($currentSide == 'A'){            $this->currentSide = 'A';            $this->lastSide = 'B';              $this->currentHead  = $this->sideAHead;            $this->currentTail  = $this->sideATail;            $this->lastHead     = $this->sideBHead;            $this->lastTail     = $this->sideBTail;                 }else{            $this->currentSide = 'B';            $this->lastSide = 'A';            $this->currentHead  = $this->sideBHead;            $this->currentTail  = $this->sideBTail;            $this->lastHead     = $this->sideAHead;            $this->lastTail     = $this->sideATail;                             }        return $this->currentSide;    }    /*     * 队列加锁     * @return boolean     */    private function getLock(){        if($this->access === false){            while(!memcache_add(self::$client, $this->queueName .self::LOCK_KEY, 1, false, $this->expire) ){                usleep($this->sleepTime);                @$i++;                if($i > $this->retryNum){//尝试等待N次                    return false;                    break;                }            }            return $this->access = true;        }        return false;    }    /*     * 队列解锁     * @return NULL     */    private function unLock(){        memcache_delete(self::$client, $this->queueName .self::LOCK_KEY);        $this->access = false;    }    /*     * 添加数据     * @param   [data]  要存储的值     * @return  boolean     */    public function add($data){        $result = false;        if(!$this->getLock()){            return $result;        }         $this->getHeadNTail($this->queueName);        $this->getCurrentSide();        if($this->isFull()){            $this->unLock();            return false;        }        if($this->currentTail < self::MAXNUM){            $value_key = $this->queueName .$this->currentSide . self::VALU_KEY . $this->currentTail;            if(memcache_add(self::$client, $value_key, $data, false, $this->expire)){                $this->changeTail();                $result = true;            }        }else{//当前队列已满,更换轮值面            $this->unLock();            $this->changeCurrentSide();            return $this->add($data);        }        $this->unLock();        return $result;    }    /*     * 取出数据     * @param   [length]    int 数据的长度     * @return  array     */    public function get($length=0){        if(!is_numeric($length)) return false;        if(empty($length)) $length = self::MAXNUM * 2;//默认读取所有        if(!$this->getLock()) return false;        if($this->isEmpty()){            $this->unLock();            return false;        }        $keyArray   = $this->getKeyArray($length);        $lastKey    = $keyArray['lastKey'];        $currentKey = $keyArray['currentKey'];        $keys       = $keyArray['keys'];        $this->changeHead($this->lastSide,$lastKey);        $this->changeHead($this->currentSide,$currentKey);        $data   = @memcache_get(self::$client, $keys);        foreach($keys as $v){//取出之后删除            @memcache_delete(self::$client, $v, 0);        }        $this->unLock();        return $data;    }    /*     * 读取数据     * @param   [length]    int 数据的长度     * @return  array     */    public function read($length=0){        if(!is_numeric($length)) return false;        if(empty($length)) $length = self::MAXNUM * 2;//默认读取所有        $keyArray   = $this->getKeyArray($length);        $data   = @memcache_get(self::$client, $keyArray['keys']);        return $data;    }    /*     * 获取队列某段长度的key数组     * @param   [length]    int 队列长度     * @return  array     */    private function getKeyArray($length){        $result = array('keys'=>array(),'lastKey'=>array(),'currentKey'=>array());        $this->getHeadNTail($this->queueName);        $this->getCurrentSide();        if(empty($length)) return $result;        //先取上一面的key        $i = $result['lastKey'] = 0;        for($i=0;$i<$length;$i++){            $result['lastKey'] = $this->lastHead + $i;            if($result['lastKey'] >= $this->lastTail) break;            $result['keys'][] = $this->queueName .$this->lastSide . self::VALU_KEY . $result['lastKey'];        }        //再取当前面的key        $j = $length - $i;        $k = $result['currentKey'] = 0;        for($k=0;$k<$j;$k++){            $result['currentKey'] = $this->currentHead + $k;            if($result['currentKey'] >= $this->currentTail) break;            $result['keys'][] = $this->queueName .$this->currentSide . self::VALU_KEY . $result['currentKey'];        }        return $result;    }    /*     * 更新当前轮值面队列尾的值     * @return  NULL     */    private function changeTail(){        $tail_key = $this->queueName .$this->currentSide . self::TAIL_KEY;        memcache_add(self::$client, $tail_key, 0,false, $this->expire);//如果没有,则插入;有则false;        //memcache_increment(self::$client, $tail_key, 1);//队列尾+1        $v = memcache_get(self::$client, $tail_key) +1;        memcache_set(self::$client, $tail_key,$v,false,$this->expire);    }    /*     * 更新队列首的值     * @param   [side]      string  要更新的面     * @param   [headValue] int     队列首的值     * @return  NULL     */    private function changeHead($side,$headValue){        if($headValue < 1) return false;        $head_key = $this->queueName .$side . self::HEAD_KEY;        $tail_key = $this->queueName .$side . self::TAIL_KEY;        $sideTail = memcache_get(self::$client, $tail_key);        if($headValue < $sideTail){            memcache_set(self::$client, $head_key,$headValue+1,false,$this->expire);        }elseif($headValue >= $sideTail){            $this->resetSide($side);        }    }    /*     * 重置队列面,即将该队列面的队首、队尾值置为0     * @param   [side]  string  要重置的面     * @return  NULL     */    private function resetSide($side){        $head_key = $this->queueName .$side . self::HEAD_KEY;        $tail_key = $this->queueName .$side . self::TAIL_KEY;        memcache_set(self::$client, $head_key,0,false,$this->expire);        memcache_set(self::$client, $tail_key,0,false,$this->expire);    }    /*     * 改变当前轮值队列面     * @return  string     */    private function changeCurrentSide(){        $currentSide = memcache_get(self::$client, $this->queueName . self::SIDE_KEY);        if($currentSide == 'A'){            memcache_set(self::$client, $this->queueName . self::SIDE_KEY,'B',false,$this->expire);            $this->currentSide = 'B';        }else{            memcache_set(self::$client, $this->queueName . self::SIDE_KEY,'A',false,$this->expire);            $this->currentSide = 'A';        }        return $this->currentSide;    }    /*     * 检查当前队列是否已满     * @return  boolean     */    public function isFull(){        $result = false;        if($this->sideATail == self::MAXNUM && $this->sideBTail == self::MAXNUM){            $result = true;        }        return $result;    }    /*     * 检查当前队列是否为空     * @return  boolean     */    public function isEmpty(){        $result = true;        if($this->sideATail > 0 || $this->sideBTail > 0){            $result = false;        }        return $result;    }    /*     * 获取当前队列的长度     * 该长度为理论长度，某些元素由于过期失效而丢失，真实长度小于或等于该长度     * @return  int     */    public function getQueueLength(){        $this->getHeadNTail($this->queueName);        $this->getCurrentSide();        $sideALength = $this->sideATail - $this->sideAHead;        $sideBLength = $this->sideBTail - $this->sideBHead;        $result = $sideALength + $sideBLength;        return $result;    }    /*     * 清空当前队列数据,仅保留HEAD_KEY、TAIL_KEY、SIDE_KEY三个key     * @return  boolean     */    public function clear(){        if(!$this->getLock()) return false;        for($i=0;$i<:maxnum this-="">queueName.'A'. self::VALU_KEY .$i, 0);            @memcache_delete(self::$client, $this->queueName.'B'. self::VALU_KEY .$i, 0);        }        $this->unLock();        $this->resetSide('A');        $this->resetSide('B');        return true;    }    /*     * 清除所有memcache缓存数据     * @return  NULL     */    public function memFlush(){        memcache_flush(self::$client); 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