NSTimer不起作用(NSTimer doesn't work)

 主要问题 
 
 我正在为Socket Rocket实现带宽管理。 为了减少Socket Rocket中的更改量，我决定创建NSOutputStream子类，它将包装为套接字创建的NSOutputStream 。 概念非常好，应该像魅力一样工作。 
 
 遇到问题 
 
 在- (NSInteger)write:(const uint8_t *)buffer maxLength:(NSUInteger)len方法如果可以发送数据，我将从带宽管理器进行排队。 如果没有带宽管理器给我下一次写操作所需的延迟。 
 
 所以我的代码看起来或多或少像这样： 
 
- (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，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和我的包装类正在回收所有通知，所以我排除了所有明显的错误。 
 
 仍然出于一些神秘的原因， notifyReadyToWrite:永远不会被调用。 有没有人知道为什么？ 

Main problem
 
I'm implementing bandwidth management for Socket Rocket. To reduce amount of alteration in Socket Rocket I've decided to create subclass of NSOutputStream which will wrap NSOutputStream created for a socket. Concept is quite nice and should work like charm.
 
Encounter problem
 
In - (NSInteger)write:(const uint8_t *)buffer maxLength:(NSUInteger)len method I'm queering from bandwidth manager if data can be send or not. If not bandwidth manager gives me required delay for next write operation.
 
So my code looks more or less like this:
 
- (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];
    }
}
 
In logs I can see, (there is a run loop and it contains created timer):
 
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)
},

}
}
 
Now I have a run loop my custom stream and wrapped stream are scheduled in this run loop, so socket rocket and my wrapping class are reciveing all notifications, so I've rule out all obvious mistakes.
 
Still for some mysterious reason notifyReadyToWrite: is never called. Does anyone have a clue why?

原文：https://stackoverflow.com/questions/37214784