/*创建请求,添加请求到数组中
  WhdeSession请求失败,取消请求等需要从数组中移除*/
static func asynDownload(urlStr:NSString, progress:ProgressBlock, success:SuccessBlock, failure:FailureBlock) ->WhdeSession

/*取消请求,移除数组中对应的请求*/
static func cancel(urlStr:String)

/*暂停,即为取消请求*/
static func pause(urlStr:String)

/*根据NSURL获取存储的路径,文件不一定存在
  文件名为Url base64转换*/
static func filePath(url:NSURL) -> String

/*获取对应文件的大小*/
static func fileSize(url:NSURL) -> UInt64

/*根据url删除对应的文件*/
static func deleteFile(url:NSURL) ->Bool

/*创建请求,开始下载,设置已经下载的位置*/
func asynDownload(urlStr:NSString, progress:ProgressBlock, success:SuccessBlock, failure:FailureBlock, callCancel:CallCancel) ->WhdeSession 

/*取消下载*/
func cancel() -> Void

/*暂停下载即为取消下载*/
func pause() -> Void 

/*出现错误,取消请求,通知失败*/
internal func URLSession(session: NSURLSession, didBecomeInvalidWithError error: NSError?)

/*下载完成*/
internal func URLSession(session: NSURLSession, task: NSURLSessionTask, didCompleteWithError error: NSError?)

/*接收到数据,将数据存储*/
internal func URLSession(session: NSURLSession, dataTask: NSURLSessionDataTask, didReceiveData data: NSData) {
     let response:NSHTTPURLResponse = dataTask.response as! NSHTTPURLResponse
     if response.statusCode == 200 {
         /*无断点续传时候,一直走200*/
         self.progressBlock!(progress:(Float.init(dataTask.countOfBytesReceived)/Float.init(dataTask.countOfBytesExpectedToReceive)), receiveByte: dataTask.countOfBytesReceived, allByte: dataTask.countOfBytesExpectedToReceive)
         self.save(data)
     } else if response.statusCode == 206 {
         /*断点续传后,一直走206*/
         self.progressBlock!(progress:((Float.init(dataTask.countOfBytesReceived+Int64.init(startFileSize))/Float.init(dataTask.countOfBytesExpectedToReceive+Int64.init(startFileSize)))), receiveByte: dataTask.countOfBytesReceived, allByte: dataTask.countOfBytesExpectedToReceive);
         self.save(data)
     }
 }

/*存储数据,将offset标到文件末尾,在末尾写入数据,最后关闭文件*/
func save(data:NSData) -> Void

    var urlStr: String?="http://dlsw.baidu.com/sw-search-sp/soft/2a/25677/QQ_V4.1.1.1456905733.dmg"
    /*开始下载
      继续下载*/
    @IBAction func start(sender: AnyObject) {

        WhdeBreakPoint.asynDownload(urlStr!, progress: { (progress, receiveByte, allByte) in
            self.progressView.progress = progress
            self.progressLabel.text = "\(Int.init(progress*100))%"
            }, success: { (filePath) in
                print("success:"+(filePath as String))
        }) { (filePath) in
            print("success:"+(filePath as String))
        }
    }

    /*根据Url暂停*/
    @IBAction func pause(sender: AnyObject) {
        WhdeBreakPoint.pause(urlStr!)
    }
    /*根据Url去删除文件*/
    @IBAction func deleteFile(sender: AnyObject) {
        WhdeFileManager.deleteFile(NSURL.init(string: urlStr!)!)
    }