php自己实现memcached的队列类
<?php
/*
* memcache队列类
* 支持多进程并发写入、读取
* 边写边读,AB面轮值替换
* @author lkk/lianq.net
* @create on 9:25 2012-9-28
*
*
* @example:
* $obj = new memcacheQueue('duilie');
* $obj->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<self::MAXNUM;$i++){
@memcache_delete(self::$client, $this->queueName.'A'. self::VALU_KEY .$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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