这是我今天早些时候发表的一篇文章中提出的第二个问题。我有下面的方法,它适用于我需要的,但有时当我在CFRelease
变量上调用hostRef
时崩溃。我认为它可能与我试图释放它时在其他地方使用的资源有关,但据我所知,我正在同步解析主机而我不会从另一个线程访问它。
我尝试在CFHostCancelInfoResolution
之前调用CFRelease
,但这并没有改变崩溃的频率。我想我会在这里张贴这个,看看是否有一些假设或误解我不是真的。
+ (NSArray *) addressesForHostname: (NSString *)hostname {
CFMutableArrayRef ipAddresses = nil;
DLog(@"Getting addresses for host name %@", hostname);
CFHostRef hostRef = CFHostCreateWithName(kCFAllocatorDefault, (__bridge CFStringRef)(hostname));
CFStreamError error;
BOOL didResolve = CFHostStartInfoResolution(hostRef, kCFHostAddresses, &error); // synchronously get the host.
if (didResolve) {
CFArrayRef responseObjects = CFHostGetAddressing(hostRef, NULL);
long numberOfResponses = CFArrayGetCount(responseObjects);
ipAddresses = CFArrayCreateMutable(kCFAllocatorDefault, numberOfResponses, &kCFTypeArrayCallBacks);
for ( int i = 0 ; i < numberOfResponses; ++i ) {
char * ipAddress = NULL;
CFDataRef responseObject = CFArrayGetValueAtIndex(responseObjects, i);
struct sockaddr * currentAddress = (struct sockaddr *) CFDataGetBytePtr(responseObject); // Unwrap the CFData wrapper aound the sockaddr struct
switch (currentAddress->sa_family) {
case AF_INET: { // Internetworking AKA IPV4
DLog(@"Extracting IPV4 address");
struct sockaddr_in * socketAddress = (struct sockaddr_in *) currentAddress;
ipAddress = malloc(sizeof(INET_ADDRSTRLEN));
inet_ntop(AF_INET,
&(socketAddress->sin_addr),
ipAddress,
INET_ADDRSTRLEN);
CFStringRef ipAddressString = CFStringCreateWithCString(kCFAllocatorDefault, ipAddress, kCFStringEncodingASCII);
CFArrayInsertValueAtIndex(ipAddresses, i, ipAddressString);
break;
}
case AF_INET6: { // IPV6
DLog(@"Extracting IPV6 address");
struct sockaddr_in6 * socketAddress = (struct sockaddr_in6 *) currentAddress;
ipAddress = malloc(sizeof(INET6_ADDRSTRLEN));
inet_ntop(AF_INET6,
&(socketAddress->sin6_addr),
ipAddress,
INET6_ADDRSTRLEN);
CFStringRef ipAddressString = CFStringCreateWithCString(kCFAllocatorDefault, ipAddress, kCFStringEncodingASCII);
CFArrayInsertValueAtIndex(ipAddresses, i, ipAddressString);
break;
}
default:
DLog(@"Unsupported addressing protocol encountered. Gracefully ignoring and continuing.");
break;
}
if(ipAddress != NULL) {
free(ipAddress);
}
}
CFRelease(responseObjects);
}
CFRelease(hostRef);
return (__bridge_transfer NSArray *) ipAddresses;
}
答案 0 :(得分:1)
删除CFRelease(responseObjects);
将解决它
答案 1 :(得分:1)
您必须遵循Core Foundation对象的创建规则。如果您通过调用其名称中包含“创建”或“复制”字样的函数(或者如果您明确调用CFRetain)来接收该对象,则必须在完成该对象时释放(CFRelease)该对象。如果您没有以这种方式接收对象,则不得释放该对象。
您的代码中存在多个错误。首先,您要找到的那个,即responseObjects
左右。您使用以下方法获取此对象:
CFDataRef responseObject = CFArrayGetValueAtIndex(responseObjects, i);
该功能的名称中没有“创建”或“复制”。您不得在其上拨打CFRelease
。
但是,你也称之为:
ipAddresses = CFArrayCreateMutable(kCFAllocatorDefault, numberOfResponses, &kCFTypeArrayCallBacks);
并且在几个地方:
CFStringRef ipAddressString = CFStringCreateWithCString(kCFAllocatorDefault, ipAddress, kCFStringEncodingASCII);
您必须在这些对象超出范围之前调用CFRelease
,否则您将泄露它们。
答案 2 :(得分:0)
我认为CFStreamError error;
可能会导致此问题。
尝试将错误声明为null?
// synchronously get the host.
BOOL didResolve = CFHostStartInfoResolution(hostRef, kCFHostAddresses, NULL);