内存泄漏问题iOS NSCFString

Question

使用join（）的原始代码显示了Instruments中的内存泄漏。我使用了一个循环，它似乎解决了这个问题。好奇，如果这似乎是一个框架问题？

 //in ViewDidLoad

      let saveButton = UIBarButtonItem(barButtonSystemItem: .Save, target: self, action: "saveBtnAc")
            self.navigationItem.rightBarButtonItem = saveButton

    //end ViewDidLoad

   //using a loop to join the string instead of join()
   func doJndString(theArray: [String]) -> String {
        var updatedAryJnd = String()
        var count = 0
        let lastItemCount = theArray.count - 1
        while (count < lastItemCount) {
              updatedAryJnd += (theArray[count] + "§")
              count++
        }
        updatedAryJnd += theArray[lastItemCount]
        return updatedAryJnd
   }

   //button action

   func saveBtnAc() {
       var myAry = [""]
       if let items1 = setupItem?.valueForKey("itemsAry1") as? String {
       myAry = items1.componentsSeparatedByString("§")
       }

       myAry[itemClkdVar] = myTxtOutlet.text

       //I get a leak when using the following join()
       //let updatedAryJnd = "§".join(myAry)
       //setupItem!.setValue(updatedAryJnd, forKey: "itemsAry1")

       //change above to this and no leak
       setupItem!.setValue(doJndString(myAry), forKey: "itemsAry1")

       var error: NSError? = nil
           if !contextOb!.save(&error) {
                println("had an error")
           }        
    }