CFReadStreamHasBytesAvailable Survey - Best Practices

Question

I am currently browsing mine CFReadStreamfor new data using CFReadStreamHasBytesAvailable.

(First, some background: I do my own streaming processing, and I don't want / should not interfere with the runloop stuff, so callback feedback sets are not applicable here).

My question is: what are the accepted practices for the survey?

Apple's documentation on this does not seem too useful.

They recommend "do something else while you wait." I'm just doing something like:

while(!done)
{
  if(CFReadStreamHasBytesAvailable(readStream))
  {
    CFReadStreamRead(...) ... bla bla bla
  } else {
    usleep(3600); // I made this up
    sched_yield(); // also made this up
    continue;
  }
}

Is it enough usleep, and sched_yield"? There is a" good "room to sleep in usleep?

(: , , CFReadStreamRead - , , , 't help...).

- !

Answer 1

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Answer 2

CFStream ( , ), CFReadStreamScheduleWithRunLoop, CFRunLoopRunInMode CFReadStreamSetClient. 0,25 , . . - , () .

static const CFOptionFlags kMyNetworkEvents =
kCFStreamEventOpenCompleted
| kCFStreamEventHasBytesAvailable
| kCFStreamEventEndEncountered
| kCFStreamEventErrorOccurred;

static void MyStreamCallBack(CFReadStreamRef readStream, CFStreamEventType type, void *clientCallBackInfo) {
    [(id)clientCallBackInfo _handleNetworkEvent:type];
}


- (void)connect {
  ...

  CFStreamClientContext streamContext = {0, self, NULL, NULL, NULL};
  BOOL success = CFReadStreamSetClient(readStream_, kMyNetworkEvents, MyStreamCallBack, &streamContext);


  CFReadStreamScheduleWithRunLoop(readStream_, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);

  if (!CFReadStreamOpen(readStream_)) {
    // Notify error
  }

  while(!cancelled_ && !finished_) {

    SInt32 result = CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.25, NO);

    if (result == kCFRunLoopRunStopped || result == kCFRunLoopRunFinished) {
      break;
    }

    if (([NSDate timeIntervalSinceReferenceDate] - lastRead_) > MyConnectionTimeout) {
      // Call timed out
      break;
    }

    // Also handle stream status CFStreamStatus status = CFReadStreamGetStatus(readStream_);
    if (![self _handleStreamStatus:status]) break;
  }

  CFRunLoopStop(CFRunLoopGetCurrent());


  CFReadStreamSetClient(readStream_, 0, NULL, NULL);
  CFReadStreamUnscheduleFromRunLoop(readStream_, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);

  CFReadStreamClose(readStream_);       

}


- (void)_handleNetworkEvent:(CFStreamEventType)type {
    switch(type) {
        case kCFStreamEventOpenCompleted:
            // Notify connected
            break;

        case kCFStreamEventHasBytesAvailable:
            [self _handleBytes];
            break;

        case kCFStreamEventErrorOccurred:
            [self _handleError];
            break;

        case kCFStreamEventEndEncountered:
            [self _handleBytes];
            [self _handleEnd];
            break;

        default:
          Debug(@"Received unexpected CFStream event (%d)", type);
            break;
    }
}