NSTimer 不起作用

Question

主要问题

我正在为 Socket Rocket 实施带宽管理。为了减少 Socket Rocket 中的更改量，我决定创建 NSOutputStream 的 subclass，它将包装为套接字创建的 NSOutputStream。概念非常好，应该很有魅力。

遇到问题

在 - (NSInteger)write:(const uint8_t *)buffer maxLength:(NSUInteger)len 方法中，我从带宽管理器查询是否可以发送数据。如果不是带宽管理器给我下一次写入操作所需的延迟。

所以我的代码大致是这样的：

- (NSInteger)write:(const uint8_t *)buffer maxLength:(NSUInteger)len
{
    auto bandwithInfo = [_bandwidthManager bandwidthInfoForSize: len];
    if (bandwithInfo.m_bOKtoSendNow)
    {
        auto actualWritten = [self.throttledStream write: buffer maxLength: len];
        if (actualWritten<0)
        {
            // report failure of sending data
            [_bandwidthManager reportNetworkBackPressure: len];
        }
        else
        {
            [_bandwidthManager ReportConsumedSendBandwidth: actualWritten];
            int bytesNotSentCount = len - actualWritten;
            if (bytesNotSentCount>0)
            {
                [_bandwidthManager ReportNetworkBackPressure: bytesNotSentCount];
            }
            [self enqueueEvent: NSStreamEventHasSpaceAvailable];
        }
        return actualWritten;
    }
    else
    {
        auto delay = bandwithInfo.m_nWaitTimeMilliseconds;
        NSASSERT(delay>0);
        [self scheduleNotifyReadyToWriteAfterMs: delay];
        return 0;
    }
}

- (void)scheduleNotifyReadyToWriteAfterMs: (int)miliseconds
{
    if (!isReadyToWriteScheduled)
    {
        isReadyToWriteScheduled = YES;
        static const NSTimeInterval kTimeIntervalMilisecond = 0.001;
        NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval: miliseconds * kTimeIntervalMilisecond
                                                          target: self
                                                        selector: @selector(notifyReadyToWrite:)
                                                        userInfo: nil
                                                         repeats: false];
        NSLog(@"timer=%@\nRunLoop=%@", timer, [NSRunLoop currentRunLoop]);
// this alternative also doesn't work:
//      [self performSelector: @selector(notifyReadyToWrite:)
//                 withObject: nil
//                 afterDelay: miliseconds * kTimeIntervalMilisecond];
    }
}

- (void)notifyReadyToWrite: (NSTimer *)timer
{
    [timer invalidate];

    if (self.hasSpaceAvailable) {
        isReadyToWriteScheduled = NO;
        [self enqueueEvent: NSStreamEventHasSpaceAvailable];
    }
}

在日志中我可以看到，（有一个运行循环并且它包含创建的计时器）：

timer=<__NSCFTimer: 0x109a96180>
RunLoop=<CFRunLoop 0x109a962d0 [0x7fff7208f440]>{wakeup port = 0x4507, stopped = false, ignoreWakeUps = true, 
current mode = (none),
common modes = <CFBasicHash 0x109a96390 [0x7fff7208f440]>{type = mutable set, count = 1,
entries =>
    2 : <CFString 0x7fff71fa1940 [0x7fff7208f440]>{contents = "kCFRunLoopDefaultMode"}
}
,
common mode items = (null),
modes = <CFBasicHash 0x109a963d0 [0x7fff7208f440]>{type = mutable set, count = 1,
entries =>
    2 : <CFRunLoopMode 0x109a96410 [0x7fff7208f440]>{name = kCFRunLoopDefaultMode, port set = 0x440b, queue = 0x109a964e0, source = 0x109a96570 (not fired), timer port = 0x4b03, 
    sources0 = (null),
    sources1 = (null),
    observers = (null),
    timers = <CFArray 0x109a95b10 [0x7fff7208f440]>{type = mutable-small, count = 1, values = (
    0 : <CFRunLoopTimer 0x109a96180 [0x7fff7208f440]>{valid = Yes, firing = No, interval = 0, tolerance = 0, next fire date = 485078914 (-0.00818103552 @ 3808422033916), callout = (NSTimer) [SRSendStreamWithThrottling notifyReadyToWrite:] (0x7fff87025d0d / 0x10264b100) (/Users/maru/Library/Developer/Xcode/DerivedData/AvayaCommonWorkspace-cnweundajqjciphewynfexnutumh/Build/Products/Debug/testrunner), context = <CFRunLoopTimer context 0x109a93370>}
)},
    currently 485078914 (3808417241824) / soft deadline in: 0.00479207 sec (@ 3808422033916) / hard deadline in: 0.004791892 sec (@ 3808422033916)
},

}
}

现在我有一个运行循环我的自定义流和包装流被安排在这个运行循环中，所以 socket rocket 和我的包装 class 正在接收所有通知，所以我已经排除了所有明显的错误。

仍然出于某种神秘原因 notifyReadyToWrite: 从未被调用。有人知道为什么吗？

Answer 1

好的，我找到了问题的根源。

当 Socket Rocket 收到 space 可用的通知时，它不会立即处理此通知，而是将通知分派到工作队列并在那里进行处理。
因此，当调用 - (NSInteger)write:(const uint8_t *)buffer maxLength:(NSUInteger)len 方法时，当前事件循环与调度队列相关联，并且该队列未完全发挥作用。您不能将计时器添加到这样的运行循环中。因此，我将定时器添加到与流关联的事件循环中，而不是将定时器添加到当前事件循环中，定时器开始工作：

- (void)scheduleNotifyReadyToWriteAfterMs: (clientsdk::MillisecondTime)miliseconds
{
    if (!isReadyToWriteScheduled)
    {
        isReadyToWriteScheduled = YES;
        static const NSTimeInterval kTimeIntervalMilisecond = 0.001;

        NSTimer *timer = [NSTimer timerWithTimeInterval: miliseconds * kTimeIntervalMilisecond
                                                 target: self
                                               selector: @selector(notifyReadyToWrite:)
                                               userInfo: nil
                                                repeats: NO];

        [self enumerateRunLoopsUsingBlock:^(CFRunLoopRef runLoop) {
            CFRunLoopAddTimer(runLoop, (CFRunLoopTimerRef)timer, kCFRunLoopCommonModes);
        }];
    }
}

这解决了 NSTimer 的问题。

NSTimer 不起作用

NSTimer doesn't work

objective-c

nstimer

nsrunloop

nsoutputstream

socketrocket

主要问题

遇到问题