Question

这是一个非常令人困惑的错误，因为即使我发送和接收有时会发生的相同数据，有时也不会。

我通过NSInputStream接收流，我使用标准代码读取该流中收到的字节并将它们传递给另一个方法，如下所示：

- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode
{
    switch (eventCode) {
        case NSStreamEventHasBytesAvailable:{

            NSMutableData *data = [[NSMutableData alloc] init];
            uint8_t buf[1024];
            NSInteger length = 0;
            length = [(NSInputStream *)aStream read:buf maxLength:1024];
            if(length>0) {
                [data appendBytes:buf length:length];
                [self.delegate doSomethingWithTheData:data];
            } else {
                NSLog(@"no buffer!");
            }

            break;
        }

    ...
}

有时当流开始接收时，我会收到行EXC_BAD_ACCESS (code = 1, address = 0x8)错误

length = [(NSInputStream *)aStream read:buf maxLength:1024];

我无法看到是什么导致了这个问题，因为aStream永远不会等于nil，因此在我阅读内部之前永远不会释放。我的理解是：maxLength返回一个NSInteger，然后以长度存储。我能想到的唯一问题是流中的数据，但除非我阅读它，否则我无法测试这些数据，这会导致恶性循环。

有什么想法吗？

修改

这是完整的堆栈跟踪：

(lldb) bt
* thread #1: tid = 0x2395e, 0x35b1d620 libsystem_kernel.dylib`syscall_thread_switch + 8, queue = 'com.apple.main-thread'
  * frame #0: 0x35b1d620 libsystem_kernel.dylib`syscall_thread_switch + 8
    frame #1: 0x35baa502 libsystem_platform.dylib`_os_lock_handoff_lock_slow + 78
    frame #2: 0x35b57e14 libsystem_malloc.dylib`szone_malloc_should_clear + 56
    frame #3: 0x35b5b400 libsystem_malloc.dylib`malloc_zone_calloc + 92
    frame #4: 0x35b5b392 libsystem_malloc.dylib`calloc + 50
    frame #5: 0x354f3410 libobjc.A.dylib`class_createInstance + 40
    frame #6: 0x27e42aa0 CoreFoundation`__CFAllocateObject2 + 12
    frame #7: 0x27d5b760 CoreFoundation`+[__NSArrayI __new:::] + 20
    frame #8: 0x27d58d84 CoreFoundation`-[__NSPlaceholderArray initWithObjects:count:] + 136
    frame #9: 0x27d5973c CoreFoundation`-[NSArray initWithArray:range:copyItems:] + 276
    frame #10: 0x27d59610 CoreFoundation`+[NSArray arrayWithArray:] + 72
    frame #11: 0x2b5b6bba UIKit`-[UIViewController _traitCollectionForChildEnvironment:] + 26
    frame #12: 0x2b2d76d8 UIKit`__45-[UIView(Hierarchy) _postMovedFromSuperview:]_block_invoke + 216
    frame #13: 0x2b2d758c UIKit`-[UIView(Hierarchy) _postMovedFromSuperview:] + 428
    frame #14: 0x2b2d6458 UIKit`-[UIView(Hierarchy) removeFromSuperview] + 404
    frame #15: 0x27d8d9bc CoreFoundation`-[NSArray makeObjectsPerformSelector:] + 196
    frame #16: 0x2b3aa814 UIKit`-[UITableView reloadData] + 1304
    frame #17: 0x0009d524 MyTestApp`-[StreamingViewController peerDisconnected](self=0x15ead880, _cmd=0x000ed1d8) + 280 at StreamingViewController.m:950
    frame #18: 0x000e48e2 MyTestApp`__34-[MainViewController disconnected]_block_invoke(.block_descriptor=0x15e8f970) + 426 at MainViewController.m:1271
    frame #19: 0x00259aea libdispatch.dylib`_dispatch_call_block_and_release + 10
    frame #20: 0x00259ad6 libdispatch.dylib`_dispatch_client_callout + 22
    frame #21: 0x0025d4f6 libdispatch.dylib`_dispatch_main_queue_callback_4CF + 810
    frame #22: 0x27e02be8 CoreFoundation`__CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 8
    frame #23: 0x27e012e8 CoreFoundation`__CFRunLoopRun + 1512
    frame #24: 0x27d4f620 CoreFoundation`CFRunLoopRunSpecific + 476
    frame #25: 0x27d4f432 CoreFoundation`CFRunLoopRunInMode + 106
    frame #26: 0x2f0fe0a8 GraphicsServices`GSEventRunModal + 136
    frame #27: 0x2b33a358 UIKit`UIApplicationMain + 1440
    frame #28: 0x000d18bc MyTestApp`main(argc=1, argv=0x0023aadc) + 116 at main.m:16

EXC_BAD_ACCESS与NSStreamEventHasBytesAvailable

0 个答案: