Apple's reachability memory leak

Question

I use apple's Reachabiliry class in my non-arc project. And when I run it with instruments to find memory leaks, it referes to Reachability method. Here is the problem:

+ (instancetype)reachabilityWithAddress:(const struct sockaddr_in *)hostAddress;
{
    SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr *)hostAddress);

    WReachability* returnValue = NULL;

    if (reachability != NULL)
    {
        returnValue = [[self alloc] init];
        if (returnValue != NULL)
        {
            returnValue->reachabilityRef = reachability;
            returnValue->localWiFiRef = NO;
        }
    }
    return returnValue;
}

The leaked objects are reachability and returnValue. I understand that SCNetworkReachabilityCreateWithAddress creates a new instance and I must CFRelease it, but it happens right in dealloc!

- (void)dealloc
{
    [self stopNotifier];
    if (reachabilityRef != NULL)
    {
        CFRelease(reachabilityRef);
    }
    [super dealloc];
}

So what can I do to avoid memory leak here?

UPD: Maybe the problem is in how reachability get called? I use this method:

+ (instancetype)reachabilityForInternetConnection;
{
    struct sockaddr_in zeroAddress;
    bzero(&zeroAddress, sizeof(zeroAddress));
    zeroAddress.sin_len = sizeof(zeroAddress);
    zeroAddress.sin_family = AF_INET;

    return [self reachabilityWithAddress:&zeroAddress];
}

Then I called Reachability like this:

[[Reachability reachabilityForInternetConnection] startNotifier];

And don't assign it to any object, just use this line. I've tried to change this calls to something like:

Reachability *reachability = [[Reachability reachabilityForInternetConnection] autorelease];
[reachability startNotifier];

But after this analyzer told me "too many autorelease".

user_1143874 · Answer

Solution with ARC enabled Reachability class.

Add CFAutorelease(ref) below the issue row.
Remove the CFRelease(self.reachabilityRef) code from dealloc

Updated dealloc

- (void)dealloc {
    [self stopNotifier];

    self.reachableBlock          = nil;
    self.unreachableBlock        = nil;
    self.reachabilityBlock       = nil;
    self.reachabilitySerialQueue = nil;
}

Updated reachabilityWithAddress

+ (instancetype)reachabilityWithAddress:(void *)hostAddress {
    SCNetworkReachabilityRef ref = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr*)hostAddress);
    if (ref) {
        id reachability = [[self alloc] initWithReachabilityRef:ref];
        CFAutorelease(ref);
        return reachability;
    }

    return nil;
}

Updated reachabilityWithHostname

+ (instancetype)reachabilityWithHostname:(NSString*)hostname {
    SCNetworkReachabilityRef ref = SCNetworkReachabilityCreateWithName(NULL, [hostname UTF8String]);
    if (ref) {
        id reachability = [[self alloc] initWithReachabilityRef:ref];
        CFAutorelease(ref);
        return reachability;
    }

    return nil;
}

Apple's reachability memory leak

6 Answers