PHP实现的memcache环形队列类实例
发布:smiling 来源: PHP粉丝网 添加日期:2021-06-14 14:49:51 浏览: 评论:0
这篇文章主要介绍了PHP实现的memcache环形队列类,实例分析了基于memcache实现环形队列的方法,涉及memcache缓存及队列的相关技巧,需要的朋友可以参考下
本文实例讲述了PHP实现的memcache环形队列类,分享给大家供大家参考,具体如下:
这里介绍了PHP实现的memcache环形队列类。没咋学过数据结构,因为业务需要,所以只是硬着头皮模拟的! 参考PHP memcache 队列代码。为使队列随时可入可出,且不受int长度越界危险(单链采取Head自增的话不作处理有越界可能),所以索性改写成环形队列。可能还有BUG,忘见谅!
- <?php
- /**
- * PHP memcache 环形队列类
- * 原作者 LKK/lianq.net
- * 修改 FoxHunter
- * 因业务需要只保留的队列中的Pop和Push,修改过期时间为0即永久
- */
- class MQueue
- {
- public static $client;
- private $expire; //过期时间,秒,1~2592000,即30天内
- private $sleepTime; //等待解锁时间,微秒
- private $queueName; //队列名称,唯一值
- private $retryNum; //尝试次数
- private $MAXNUM; //最大队列容量
- private $canRewrite; //是否可以覆写开关,满出来的内容从头部开始覆盖重写原来的数据
- private $HEAD; //下一步要进入的指针位置
- private $TAIL; //下一步要进入的指针位置
- private $LEN; //队列现有长度
- const LOCK_KEY = '_Fox_MQ_LOCK_'; //锁存储标示
- const LENGTH_KEY = '_Fox_MQ_LENGTH_'; //队列现长度存储标示
- const VALU_KEY = '_Fox_MQ_VAL_'; //队列键值存储标示
- const HEAD_KEY = '_Fox_MQ_HEAD_'; //队列HEAD指针位置标示
- const TAIL_KEY = '_Fox_MQ_TAIL_'; //队列TAIL指针位置标示
- /*
- * 构造函数
- * 对于同一个$queueName,实例化时必须保障构造函数的参数值一致,否则pop和push会导队列顺序混乱
- */
- public function __construct($queueName = '', $maxqueue = 1, $canRewrite = false, $expire = 0, $config = '')
- {
- if (emptyempty($config)) {
- self::$client = memcache_pconnect('127.0.0.1', 11211);
- } elseif (is_array($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;
- $expire = (emptyempty($expire)) ? 0 : (int) $expire + 1;
- $this->expire = $expire;
- $this->queueName = $queueName;
- $this->retryNum = 20000;
- $this->MAXNUM = $maxqueue != null ? $maxqueue : 1;
- $this->canRewrite = $canRewrite;
- $this->getHeadAndTail();
- if (!isset($this->HEAD) || emptyempty($this->HEAD))
- $this->HEAD = 0;
- if (!isset($this->TAIL) || emptyempty($this->TAIL))
- $this->TAIL = 0;
- if (!isset($this->LEN) || emptyempty($this->LEN))
- $this->LEN = 0;
- }
- //获取队列首尾指针信息和长度
- private function getHeadAndTail()
- {
- $this->HEAD = (int) memcache_get(self::$client, $this->queueName . self::HEAD_KEY);
- $this->TAIL = (int) memcache_get(self::$client, $this->queueName . self::TAIL_KEY);
- $this->LEN = (int) memcache_get(self::$client, $this->queueName . self::LENGTH_KEY);
- }
- // 利用memcache_add原子性加锁
- private function lock()
- {
- if ($this->access === false) {
- $i = 0;
- while (!memcache_add(self::$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 $this->access = true;
- }
- return false;
- }
- //更新头部指针指向,指向下一个位置
- private function incrHead()
- {
- //$this->getHeadAndTail(); //获取最新指针信息 ,由于本方法体均在锁内调用,其锁内已调用了此方法,本行注释
- $this->HEAD++; //头部指针下移
- if ($this->HEAD >= $this->MAXNUM) {
- $this->HEAD = 0; //边界值修正
- }
- ;
- $this->LEN--; //Head的移动由Pop触发,所以相当于数量减少
- if ($this->LEN < 0) {
- $this->LEN = 0; //边界值修正
- }
- ;
- memcache_set(self::$client, $this->queueName . self::HEAD_KEY, $this->HEAD, false, $this->expire); //更新
- memcache_set(self::$client, $this->queueName . self::LENGTH_KEY, $this->LEN, false, $this->expire); //更新
- }
- //更新尾部指针指向,指向下一个位置
- private function incrTail()
- {
- //$this->getHeadAndTail(); //获取最新指针信息,由于本方法体均在锁内调用,其锁内已调用了此方法,本行注释
- $this->TAIL++; //尾部指针下移
- if ($this->TAIL >= $this->MAXNUM) {
- $this->TAIL = 0; //边界值修正
- }
- ;
- $this->LEN++; //Head的移动由Push触发,所以相当于数量增加
- if ($this->LEN >= $this->MAXNUM) {
- $this->LEN = $this->MAXNUM; //边界值长度修正
- }
- ;
- memcache_set(self::$client, $this->queueName . self::TAIL_KEY, $this->TAIL, false, $this->expire); //更新
- memcache_set(self::$client, $this->queueName . self::LENGTH_KEY, $this->LEN, false, $this->expire); //更新
- }
- // 解锁
- private function unLock()
- {
- memcache_delete(self::$client, $this->queueName . self::LOCK_KEY);
- $this->access = false;
- }
- //判断是否满队列
- public function isFull()
- {
- //外部直接调用的时候由于没有锁所以此处的值是个大概值,并不很准确,但是内部调用由于在前面有lock,所以可信
- if ($this->canRewrite)
- return false;
- return $this->LEN == $this->MAXNUM ? true : false;
- }
- //判断是否为空
- public function isEmpty()
- {
- //外部直接调用的时候由于没有锁所以此处的值是个大概值,并不很准确,但是内部调用由于在前面有lock,所以可信
- return $this->LEN == 0 ? true : false;
- }
- public function getLen()
- {
- //外部直接调用的时候由于没有锁所以此处的值是个大概值,并不很准确,但是内部调用由于在前面有lock,所以可信
- return $this->LEN;
- }
- /*
- * push值
- * @param mixed 值
- * @return bool
- */
- public function push($data = '')
- {
- $result = false;
- if (emptyempty($data))
- return $result;
- if (!$this->lock()) {
- return $result;
- }
- $this->getHeadAndTail(); //获取最新指针信息
- if ($this->isFull()) { //只有在非覆写下才有Full概念
- $this->unLock();
- return false;
- }
- if (memcache_set(self::$client, $this->queueName . self::VALU_KEY . $this->TAIL, $data, MEMCACHE_COMPRESSED, $this->expire)) {
- //当推送后,发现尾部和头部重合(此时指针还未移动),且右边仍有未由Head读取的数据,那么移动Head指针,避免尾部指针跨越Head
- if ($this->TAIL == $this->HEAD && $this->LEN >= 1) {
- $this->incrHead();
- }
- $this->incrTail(); //移动尾部指针
- $result = true;
- }
- $this->unLock();
- return $result;
- }
- /*
- * Pop一个值
- * @param [length] int 队列长度
- * @return array
- */
- public function pop($length = 0)
- {
- if (!is_numeric($length))
- return false;
- if (!$this->lock())
- return false;
- $this->getHeadAndTail();
- if (emptyempty($length))
- $length = $this->LEN; //默认读取所有
- if ($this->isEmpty()) {
- $this->unLock();
- return false;
- }
- //获取长度超出队列长度后进行修正
- if ($length > $this->LEN)
- $length = $this->LEN;
- $data = $this->popKeyArray($length);
- $this->unLock();
- return $data;
- }
- /*
- * pop某段长度的值
- * @param [length] int 队列长度
- * @return array
- */
- private function popKeyArray($length)
- {
- $result = array();
- if (emptyempty($length))
- return $result;
- for ($k = 0; $k < $length; $k++) {
- $result[] = @memcache_get(self::$client, $this->queueName . self::VALU_KEY . $this->HEAD);
- @memcache_delete(self::$client, $this->queueName . self::VALU_KEY . $this->HEAD, 0);
- //当提取值后,发现头部和尾部重合(此时指针还未移动),且右边没有数据,即队列中最后一个数据被完全掏空,此时指针停留在本地不移动,队列长度变为0
- if ($this->TAIL == $this->HEAD && $this->LEN <= 1) {
- $this->LEN = 0;
- memcache_set(self::$client, $this->queueName . self::LENGTH_KEY, $this->LEN, false, $this->expire); //更新
- break;
- } else {
- $this->incrHead(); //首尾未重合,或者重合但是仍有未读取出的数据,均移动HEAD指针到下一处待读取位置
- }
- }
- return $result;
- }
- /*
- * 重置队列
- * * @return NULL
- */
- private function reset($all = false)
- {
- if ($all) {
- memcache_delete(self::$client, $this->queueName . self::HEAD_KEY, 0);
- memcache_delete(self::$client, $this->queueName . self::TAIL_KEY, 0);
- memcache_delete(self::$client, $this->queueName . self::LENGTH_KEY, 0);
- } else {
- $this->HEAD = $this->TAIL = $this->LEN = 0;
- memcache_set(self::$client, $this->queueName . self::HEAD_KEY, 0, false, $this->expire);
- memcache_set(self::$client, $this->queueName . self::TAIL_KEY, 0, false, $this->expire);
- memcache_set(self::$client, $this->queueName . self::LENGTH_KEY, 0, false, $this->expire);
- }
- }
- /*
- * 清除所有memcache缓存数据
- * @return NULL
- */
- public function memFlush()
- {
- memcache_flush(self::$client);
- }
- public function clear($all = false)
- {
- if (!$this->lock())
- return false;
- $this->getHeadAndTail();
- $Head = $this->HEAD;
- $Length = $this->LEN;
- $curr = 0;
- for ($i = 0; $i < $Length; $i++) {
- $curr = $this->$Head + $i;
- if ($curr >= $this->MAXNUM) {
- $this->HEAD = $curr = 0;
- }
- @memcache_delete(self::$client, $this->queueName . self::VALU_KEY . $curr, 0);
- }
- $this->unLock();
- $this->reset($all);
- return true;
- }
- }
希望本文所述对大家的php程序设计有所帮助。
Tags: memcache PHP环形队列类
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