我注意到在我的程序中使用CFStreamCreatePairWithSocketToHost时出现了随机的EXC_BADACCESS错误,但只有ios6 – 当使用ios5模拟器时(甚至在带有
xcode4.5的ios6sdk内部)一切正常.我最终将问题提取到一个小的测试程序中 – 如果你启用了guard malloc,它会立即爆炸(见下面的崩溃).这也发生在弧形和非弧形的情况下.
@interface PHAppDelegate : UIResponder <UIApplicationDelegate,NSStreamDelegate>
{
NSOutputStream* mOutputStream;
NSInputStream* mInputStream;
}
@implementation PHAppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSString* testAddress = @"192.168.1.0";
[self openWithHost:testAddress port:444];
return YES;
}
- (void)openWithHost:(NSString*)host port:(int)port
{
CFReadStreamRef readStream;
CFWriteStreamRef writeStream;
CFStreamCreatePairWithSocketToHost(kcfAllocatorDefault,(CFStringRef)host,/*ip_addr*/
port,&readStream,&writeStream);
mInputStream = (NSInputStream *)readStream;
mOutputStream = (NSOutputStream *)writeStream;
if (mInputStream == nil)
{
NSLog(@"couldn't create the inputStream using CFStreamCreatePairWithSocketsToHost()");
return;
}
if (mOutputStream == nil)
{
NSLog(@"couldn't create the outputstream using CFStreamCreatePairWithSocketsToHost()");
return;
}
[mInputStream setDelegate:self];
[mOutputStream setDelegate:self];
[mInputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[mOutputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[mInputStream open];
[mOutputStream open];
}
#pragma mark NSStream delegate methods
- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode
{
NSLog(@"stream-handleEvent");
}
@end
在com.apple.networking.connection线程中崩溃：
#0 0x04b35140 in tcp_connection_destination_prepare_complete () #1 0x04b34fee in tcp_connection_destination_start () #2 0x04b34c2b in tcp_connection_start_next_destination () #3 0x04b33c70 in tcp_connection_handle_reachability_changed () #4 0x04b30a95 in __tcp_connection_start_block_invoke_0 () #5 0x049fa53f in _dispatch_call_block_and_release () #6 0x04a0c014 in _dispatch_client_callout () #7 0x049fc418 in _dispatch_queue_drain () #8 0x049fc2a6 in _dispatch_queue_invoke () #9 0x049fd280 in _dispatch_root_queue_drain () #10 0x049fd450 in _dispatch_worker_thread2 () #11 0x94e7de12 in _pthread_wqthread () #12 0x94e65cca in start_wqthread () EXC_BADACCESS @ address 0x04b35140 0x04b3513b <+0072> call 0x4b332de <tcp_connection_destination_list_remove> 0x04b35140 <+0077> mov 0x28(%esi),%eax 0x04b35143 <+0080> test %eax,%eax
解决方法
我有非常相似的代码,适用于iOS 5.x和iOS 6.x.唯一的区别是我在调用CFStreamCreatePairWithSocketToHost之前将CFReadStreamRef和CFWriteStreamRef初始化为NULL,并为分配器传递NULL.为方便起见,我通常还会在NSStream上将代码添加为类别.所以,代码看起来像这样：
+ (void)createStreamsToHostNamed:(NSString*)hostName port:(NSInteger)port inputStream:(NSInputStream* __autoreleasing *)inputStream outputStream:(NSOutputStream* __autoreleasing *)outputStream {
CFReadStreamRef readStream = NULL;
CFWriteStreamRef writeStream = NULL;
// Create a pair of of streams for a socket to the host specified
CFStreamCreatePairWithSocketToHost(NULL,(__bridge CFStringRef)hostName,port,&writeStream);
// Assign the output parameters
*inputStream = (__bridge_transfer NSInputStream*)readStream;
*outputStream = (__bridge_transfer NSOutputStream*)writeStream;
}
@interface SomeClass : NSObject <NSStreamDelegate>
@end
@implementation SomeClass {
NSInputStream* _inputStream;
NSOutputStream* _outputStream;
}
- (void)_setupMethod {
__autoreleasing NSInputStream* autoreleasingInputStream = nil;
__autoreleasing NSOutputStream* autoreleasingOutputStream = nil;
[NSStream createStreamsToHostNamed:kHostConstant port:kPortConstant inputStream:&autoreleasingInputStream outputStream:&autoreleasingOutputStream];
if(autoreleasingInputStream != nil && autoreleasingOutputStream != nil) {
_inputStream = autoreleasingInputStream;
[_inputStream setDelegate:self];
[_inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
_outputStream = autoreleasingOutputStream;
[_outputStream setDelegate:self];
[_outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[_inputStream open];
[_outputStream open];
}
}
// NSStreamDelegate methods ...
@end
