<?php
// 使用Memache 作為進(jìn)程鎖 
class lock_processlock{
 
 
 // key 的前綴
 protected $sLockKeyPre;
 // 重試間隔
 protected $iLockRetryInterval;
 //重試次數(shù) 
 protected $iLockRetryCount;
 //鎖的過(guò)期時(shí)間
 protected $iLockCacheTimeout;
 // 鎖過(guò)期后的回調(diào)函數(shù)
 protected $onLockTimeoutFunc;
 // memache 的實(shí)例
 protected $oMemcache;
 // 存儲(chǔ)memcache失敗后重試次數(shù) 
 protected $iMemcacheRetryCount;
 
 
 
 
  public function __construct ($onLockTimeoutFunc=NULL) {
  $aLockConfig = get_config('', 'lock');
  $this->sLockKeyPre = self::LOCK_KEY_PRE;
  $this->iLockRetryInterval = self::LOCK_RETRY_INTERVAL;
  $this->iLockRetryCount =self::LOCK_RETRY_COUNT;
  $this->iLockCacheTimeout = self::LOCK_CACHE_TIMEOUT;
  $this->iMemcacheRetryCount = self::LOCK_CACHE_TIMEOUT;
  if(!$onLockTimeoutFunc){
   // 如果加鎖不成功則調(diào)用回調(diào)函數(shù),如果沒(méi)有回調(diào)函數(shù),使用本類(lèi)中所帶的 
   $onLockTimeoutFunc ='onLockTimeout' ; 
  }
  $this->onLockTimeoutFunc = $onLockTimeoutFunc;
 }
 
 
 /**
 連接memcache 服務(wù)器 
 */
 public function connect() {
  if (! isset ( $this->oMemcache )) {
   $this->oMemcache = new Memcache ();
   $this->oMemcache->connect ( '127.0.0.1', 11211 );
  }
  return $this->oMemcache;
 }
 
 
 /*
 向MeMcache中添加 key
 */
 public addMemcache($sKey, $sValue, $iTimeout){
  
  for($i= 0 ; $i<$this->iMemcacheRetryCount){
   $bRes = $this->oMemcache->add($sKey, $sValue, $iTimeout);
   if($bRes){
    return true ; 
   }
    // 如果加鎖不成功,sleep 之后,從新加鎖
   usleep($this->iLockRetryInterval*1000);
   
  }
  return false ; 
  
 }
 
 
 /*
 加鎖 
 */
 public function lock($sLockID){
  
  $oMemcache = $this->connect();
  $sKey = $this->sLockKeyPre . $sLockID;
  
  // 加鎖如果不成功可以多試幾次 
  
  for($i = 0 ; $i <$this->iLockRetryCount ; $i++){
   
   // 這里設(shè)置value 的值可以隨便設(shè)置 
   if($this->addMemcache($sKey,'1',$this->iLockCacheTimeout)){
    return true ; 
   }
   
   // 如果加鎖不成功,sleep 之后,從新加鎖
   usleep($this->iLockRetryInterval*1000);
   
  }
  
  // 若還不成功,則加鎖失敗,調(diào)用回調(diào)函數(shù),.也就是失敗后需要處理的操作 
  if(is_callable($this->onLockTimeoutFunc)){
   // 調(diào)用函數(shù) 
   call_user_func($this->onLockTimeoutFunc); 
  }
  
 }
 
 
 /*
 解鎖操作 
 */
 public function unlock($sLockID){
  
  $oMemcache = $this->connect();
  $sKey = $this->sLockKeyPre . $sLockID;
  // 刪除key
  return $this->oMemcache->delete($sKey);
  
 }
 
 
 /**
 如果加鎖不成功,則執(zhí)行如下操作 
 */
  public function onLockTimeout(){
   
   echo ("加鎖超時(shí)");
  }
  
}
// 應(yīng)用實(shí)例 
 $oLock = new lock_processlock();
 $lockResource = "test";
 // 加鎖
 $oLock->lock($lockResource);
 // 解鎖
 $oLock->unlock($lockResource);