PHP memcache 環形佇列

PHP memcache 環形佇列類別。新手，沒咋學過資料結構，因為業務需要，所以只是硬著頭皮模擬的！ 原形是 oschina上 lusi 分享的PHP memcache 佇列程式碼。為使隊列隨時可入可出，且不受int長度越界危險（單鏈採取Head自增的話不作處理有越界可能），所以索性改寫成環形隊列。可能還有BUG，忘見諒！

/**
 * PHP memcache 環形隊列類
 * 原作者LKK/lianq.net
 * 修改FoxHunter
 * 因業務需要只保留的隊列中的Pop和Push,修改過期時間為0即永久
*/
class MQueue
{
 public static $client;

 private $expire; //過期時間,秒,1~2592000,即30天內
 private $sleepTime; //等待解鎖時間,微秒
 private $queueName; //隊列名稱,唯一值
 private $retryNum; //嘗試次數
 private $MAXNUM; //最大隊列容量
 private $canRewrite; //是否可以覆蓋開關，滿出來的內容從頭部開始覆蓋重寫原來的資料

 private $HEAD; //下一步要進入的指標位置
 private $TAIL; //下一步要進入的指標位置
 private $LEN; //佇列現有長度

 const LOCK_KEY = '_Fox_MQ_LOCK_'; //鎖定儲存標示
 const LENGTH_KEY = '_Fox_MQ_LENGTH_'; //佇列長度儲存標示
 constst //值佇列值 =標示
 const HEAD_KEY = '_Fox_MQ_HEAD_'; //佇列HEAD指標位置標示
 const TAIL_KEY = '_Fox_MQ_TAIL_'; //TAILIL_1,


 * 程式碼> 🎜> * 對於同一個$queueName，實例化時必須保障建構子的參數值一致，否則pop和push會導佇列順序混亂
 */
 public function __construct($queueName = '', $maxqueue = 1, $canRewrite = false, $expire = 0, $config = '')
 {
 if (empty($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); //當客戶斷開連接,允許繼續執行
 set_time_limit(0); //取消腳本執行延遲上限
 $this->access = false;
 $this->sleepTime = 1000;
 $expire = (empty($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) || empty($this-> HEAD))
 $this->HEAD = 0;
 if (!isset($this->TAIL) || empty($this->TAIL))
 $this->TAIL = 0;
 if (!isset($this->LEN) || empty($this->LEN))
 $this->LEN = 0;

 }

 / /取得佇列首尾指標資訊與長度
 private function getHeadAndTail()
 {
 $this->HEAD = (int) memcache_get(self::$client, $this->queueName . self::HEmemcache_get(self::$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原子性加鎖
 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) { //嘗試等待N次
 return false;
 break;
 }
 }
 return $this->access = true;
 }
 return false;
 }
 }
 return false;
 }
 }
 return false;
 }
 }
 return false; } } return false; } } return false; } } return false; } } return false; } } return false; }} > //更新頭部指標指向,指向下一個位置 private function incrHead() { //$this->getHeadAndTail(); //取得最新指標資訊,由於本方法體均在鎖內調用，其鎖內已調用了此方法，本行註釋 $this->HEAD ; //頭部指針下移 if ($this->HEAD >= $this->MAXNUM ) { $this->HEAD = 0; //邊界值修正 }
 ;
 $this->LEN--; //Head的移動由Pop觸發，所以相當於數量減少
 if ($this->LEN  $this-> LEN = 0; //邊界值修正
 }
 ;
 memcache_set(self::$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

 }

 //更新尾部指標指向，指向下一個位置
 private function incrTail()
 {

 //$this->getHeadAndTail(); / /取得最新指針訊息，由於本方法體均在鎖內調用，其鎖內已調用了此方法，本行註釋
 $this->TAIL ; //尾部指針下移
 if ($this ->TAIL >= $this->MAXNUM) {
 $this->TAIL = 0; //邊界值修正
 }
 ;
 $this->LEN ; //Head的移動由Push觸發，所以相當於數量增加
 if ($this->LEN >= $this->MAXNUM) {
 $this->LEN = $this->MAXNUM; //邊界值長度修正
 }
 ;
 memcache_set(self::$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
 }


 // 解鎖
 private function unLock()
 {
 memcache_delete(self::$client, $this->queueName . self::LOCK_KEY);
 $this->access = false;
 }

 //判斷是否滿隊列
 public function isFull()
 {
 //外部直接呼叫的時候由於沒有鎖定所以此處的值是個大概值，並不很準確，但內部呼叫由於在前面有lock，所以可信
 if ($this->canRewrite)
 return false;
 return $this->LEN == $this->MAXNUM ? true : false;
 }

 //判斷是否為空
 public function isEmpty()
 {
 //外部直接呼叫的時候由於沒有鎖定所以此處的值是個大概值，不太準確，但是內部呼叫由於在前面有lock，所以可信
 return $this->LEN == 0 ? true : false;
 }

 public function getLen()
 {
 //外部直接呼叫的時候由於沒有鎖所以此處的值是個大概值，並不很準確，但是內部呼叫由於在前面有lock，所以可信
 return $this->LEN;
 }

 /*
 * push值
 * @param mixed 值
 * @return bool
 */
 public function push ($data = '')
 {

 $result = false;
 if (empty($data))
 return $result;

 if (!$ this->lock()) {
 return $result;
 }

 $this->getHeadAndTail(); //取得最新指標資訊

 if ($this- >isFull()) { //只有在非覆寫下才有Full概念
 $this->unLock();
 return false;
 }

 if (memcache_set(self ::$client, $this->queueName . self::VALU_KEY . $this->TAIL, $data, MEMCACHE_COMPRESSED, $this->expire)) {
 //當推送後，發現尾部和頭部重疊（此時指針還未移動），且右邊仍有未由Head讀取的數據，那麼移動Head指針，避免尾部指針跨越Head
 if ($this->TAIL == $this->HEAD && $ this->LEN >= 1) {
 $this->incrHead();
 }
 $this->incrTail(); //移動尾部指針
 $result = true;
 }

 $this->unLock();
 return $result;
 }


 /*
 * Pop一個值
 * @ param [length] int 佇列長度
 * @return array
 */
 public function pop($length = 0)
 {
 if (!is_numeric($length))
 return false;

 if (!$this->lock())
 return false;

 $this->getHeadAndTail();

 if (empty( $length))
 $length = $this->LEN; //預設讀取所有

 if ($this->isEmpty()) {
 $this->unLock();
 return false;
 }
 //取得長度超出佇列長度後修正
 if ($length > $this->LEN)
 $length = $this->LEN;

 $data = $this->popKeyArray($length);
 $this->unLock();
 return $data;
 }


 /*
 * pop某段長度的值
 * @param [length] int 佇列長度
 * @return array
 */
 private ftion popKeyArray($length)
 {

 $result = array();
 if (empty($length))
 return $result;
 for ($k = 0; $k  $result[] = @memcache_get(self::$client, $this->queueName . self::VALU_KEY . $this->HEAD);
 @memcache_delete (self::$client, $this->queueName . self::VALU_KEY . $this->HEAD, 0);
 //當提取值後，發現頭部和尾部重合（此時指針還未移動），且右邊沒有數據，即隊列中最後一個數據被完全掏空，此時指針停留在本地不移動，隊列長度變為0
 if ($this->TAIL == $this->HEAD && $this->LEN  $this->LEN = 0;
 memcache_set(self::$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讀取出的數據，皆移動HEAD指標到下一個待讀取位置
 }
 }
 return $result;
 }

 /*
 * 重設佇列
 * * @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, $f::$client, $ this->queueName . self::LENGTH_KEY, 0);
 } else {
 $this->HEAD = $this->TAIL = $this->LEN = 0;
 meacheache_set(selfmc:: $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快取資料
 * @return NULL
 */
 public function memFlush()
 {
 meachebdush$ );
 }


 public function clear($all = false)
 {
 if (!$this->lock())
 return false;
 $this->getHeadAndTail();
 $Head = $this->HEAD;
 $Length = $this->LEN;
 $curr = 0;
 for ($i = 0 ; $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;
 }


}