取消操作时,使用ASIHTTPRequest和NSOperationQueue崩溃

Question

在尝试取消NSOperationQueue中的请求时,我真的很难过.

重新分配我的"发动机"对象之前,我称之为cancelOperations方法来取消队列中的一切,所以这将包括在飞行ASIHTTPRequests和排队的...如

Engine.m

-(void)getContent {
    if (![self queue]) {
        [self setQueue:[[[NSOperationQueue alloc] init] autorelease]];
    }

    NSURL *url = [NSURL URLWithString:@"http://allseeing-i.com"];
    ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
    [request setDelegate:self];
    [request setDidFinishSelector:@selector(requestDone:)];
    [[self queue] addOperation:request]; //queue is an NSOperationQueue
}

-(void)requestDone:(ASIHTTPRequest)*request {

    // Do something with request
}

-(void)cancelOperations {
    [self.queue cancelAllOperations];
    [self.queue waitUntilAllOperationsAreFinished];
}

-(void)dealloc {
    [super dealloc];
}

现在,在我的引擎中,我有许多getContent类型的方法,所以我的队列中有不同的请求对象.使用Engine对象时的流程是:

1)打开视图控制器-视图没有负载- alloc和初始化引擎对象
2)//调用各种风格的getContent方法排队一些操作
3)在视图出口,调用[发动机cancelOperations]; 为了(a)停止在飞行中的任何网络的请求,并且还清空队列
4)解除分配图,并且与该发动机:发动机释放];

如果所有的请求都在队列中完成(因为它是空的)这工作得很好,但是如果我cancelOperations同时请求被激活,应用程序崩溃与一个EXC_BAD_ACCESS错误......但毕竟发动机成功地释放......

任何想法为什么会这样？

--EDIT--为错误添加Backtrace:

Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x00000000b0000000
Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Application Specific Information:
objc_msgSend() selector name: respondsToSelector:
iPhone Simulator 225, iPhone OS 4.1 (iPhone 4/8B117)

Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
0   libobjc.A.dylib                 0x02cb5907 objc_msgSend + 27
1   CoreFoundation                  0x02ac95cd __invoking___ + 29
2   CoreFoundation                  0x02ac94a1 -[NSInvocation invoke] + 145
3   Foundation                      0x0015a3ca __NSThreadPerformPerform + 251
4   CoreFoundation                  0x02b39faf __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
5   CoreFoundation                  0x02a9839b __CFRunLoopDoSources0 + 571
6   CoreFoundation                  0x02a97896 __CFRunLoopRun + 470
7   CoreFoundation                  0x02a97350 CFRunLoopRunSpecific + 208
8   CoreFoundation                  0x02a97271 CFRunLoopRunInMode + 97
9   GraphicsServices                0x0320c00c GSEventRunModal + 217
10  GraphicsServices                0x0320c0d1 GSEventRun + 115
11  UIKit                           0x003e9af2 UIApplicationMain + 1160
12  Clicky                          0x000027d4 main + 102 (main.m:14)
13  Clicky                          0x00002765 start + 53

Thread 1:  Dispatch queue: com.apple.libdispatch-manager
0   libSystem.B.dylib               0x97cfe942 kevent + 10
1   libSystem.B.dylib               0x97cff05c _dispatch_mgr_invoke + 215
2   libSystem.B.dylib               0x97cfe519 _dispatch_queue_invoke + 163
3   libSystem.B.dylib               0x97cfe2be _dispatch_worker_thread2 + 240
4   libSystem.B.dylib               0x97cfdd41 _pthread_wqthread + 390
5   libSystem.B.dylib               0x97cfdb86 start_wqthread + 30

Thread 2:
0   libSystem.B.dylib               0x97cfd9d2 __workq_kernreturn + 10
1   libSystem.B.dylib               0x97cfdf68 _pthread_wqthread + 941
2   libSystem.B.dylib               0x97cfdb86 start_wqthread + 30

Thread 3:  WebThread
0   libSystem.B.dylib               0x97cd80fa mach_msg_trap + 10
1   libSystem.B.dylib               0x97cd8867 mach_msg + 68
2   CoreFoundation                  0x02b3a436 __CFRunLoopServiceMachPort + 150
3   CoreFoundation                  0x02a97984 __CFRunLoopRun + 708
4   CoreFoundation                  0x02a97350 CFRunLoopRunSpecific + 208
5   CoreFoundation                  0x02a97271 CFRunLoopRunInMode + 97
6   WebCore                         0x034093a3 RunWebThread(void*) + 483
7   libSystem.B.dylib               0x97d0581d _pthread_start + 345
8   libSystem.B.dylib               0x97d056a2 thread_start + 34

Thread 4:
0   libSystem.B.dylib               0x97cfd9d2 __workq_kernreturn + 10
1   libSystem.B.dylib               0x97cfdf68 _pthread_wqthread + 941
2   libSystem.B.dylib               0x97cfdb86 start_wqthread + 30

Thread 5:
0   libSystem.B.dylib               0x97cd80fa mach_msg_trap + 10
1   libSystem.B.dylib               0x97cd8867 mach_msg + 68
2   CoreFoundation                  0x02b3a436 __CFRunLoopServiceMachPort + 150
3   CoreFoundation                  0x02a97984 __CFRunLoopRun + 708
4   CoreFoundation                  0x02a97350 CFRunLoopRunSpecific + 208
5   CoreFoundation                  0x02a9a614 CFRunLoopRun + 84
6   Clicky                          0x0001fdb7 +[ASIHTTPRequest runRequests] + 167 (ASIHTTPRequest.m:4093)
7   Foundation                      0x0014576c -[NSThread main] + 81
8   Foundation                      0x001456f8 __NSThread__main__ + 1387
9   libSystem.B.dylib               0x97d0581d _pthread_start + 345
10  libSystem.B.dylib               0x97d056a2 thread_start + 34

Thread 6:
0   libSystem.B.dylib               0x97cd80fa mach_msg_trap + 10
1   libSystem.B.dylib               0x97cd8867 mach_msg + 68
2   CoreFoundation                  0x02b3a436 __CFRunLoopServiceMachPort + 150
3   CoreFoundation                  0x02a97984 __CFRunLoopRun + 708
4   CoreFoundation                  0x02a97350 CFRunLoopRunSpecific + 208
5   CoreFoundation                  0x02a97271 CFRunLoopRunInMode + 97
6   Foundation                      0x0017ab86 +[NSURLConnection(NSURLConnectionReallyInternal) _resourceLoadLoop:] + 398
7   Foundation                      0x0014576c -[NSThread main] + 81
8   Foundation                      0x001456f8 __NSThread__main__ + 1387
9   libSystem.B.dylib               0x97d0581d _pthread_start + 345
10  libSystem.B.dylib               0x97d056a2 thread_start + 34

Thread 7:
0   libSystem.B.dylib               0x97cf7086 select$DARWIN_EXTSN + 10
1   CoreFoundation                  0x02acbb5e __CFSocketManager + 798
2   libSystem.B.dylib               0x97d0581d _pthread_start + 345
3   libSystem.B.dylib               0x97d056a2 thread_start + 34

Thread 8:
0   libSystem.B.dylib               0x97cfd9d2 __workq_kernreturn + 10
1   libSystem.B.dylib               0x97cfdf68 _pthread_wqthread + 941
2   libSystem.B.dylib               0x97cfdb86 start_wqthread + 30

Thread 0 crashed with X86 Thread State (32-bit):
  eax: 0x06641500  ebx: 0x000143f3  ecx: 0x0008e1c8  edx: 0x06606075
  edi: 0xb0000000  esi: 0x066554c4  ebp: 0xbfffdef8  esp: 0xbfffdec4
   ss: 0x0000001f  efl: 0x00010206  eip: 0x02cb5907   cs: 0x00000017
   ds: 0x0000001f   es: 0x0000001f   fs: 0x00000000   gs: 0x00000037
  cr2: 0xb0000000

Answer 1

你没有在dealloc中释放你的操作队列...

一个嫌疑人是委托模式：

[request setDelegate:self];

如果self对象被销毁，而请求没有被销毁，那么当请求“完成”时，它将尝试通知内存中的一些垃圾，从而崩溃。

更新：要修补此问题，请在取消之前添加以下代码：

for (ASIHTTPRequest *request in queue.operations) 
{ 
    [request setDelegate: nil]; 
    [request setDidFinishSelector: nil];
}