"Capturing 'self' strongly in this block is likely to lead to a retain cycle" using Reachability - objective-c

Question

I'm trying to edit a variable inside the Reachability block using Objective-C, this is the code:
- (void)testInternetConnection
{
internetReachableFoo = [Reachability reachabilityWithHostname:#"www.google.com"];
// Internet is reachable
internetReachableFoo.reachableBlock = ^(Reachability*reach)
{
// Update the UI on the main thread
dispatch_async(dispatch_get_main_queue(), ^{
NSLog(#"Connessione ad Internet disponibile");
checkConnection = YES;
if(!lastConnectionState)
{
lastConnectionState = YES;
if(doItemsDownload)
[self displayChoice];
}
});
};
// Internet is not reachable
internetReachableFoo.unreachableBlock = ^(Reachability*reach)
{
// Update the UI on the main thread
dispatch_async(dispatch_get_main_queue(), ^{
NSLog(#"Connessione ad Internet non disponibile");
checkConnection = NO;
lastConnectionState = NO;
});
};
[internetReachableFoo startNotifier];
}
Where checkConnection; & lastConnectionState; are 2 bool declared on my #interface;
The problem is that accessing these variables and calling [self displayChoice]; inside this block gives me the warning: Capturing 'self' strongly in this block is likely to lead to a retain cycle
How can I possibly avoid this error?
I tried declaring a WeakSelf and declaring self but I don't know how to do it for the bool variables

Answer 1

Capturing self strongly in a block is not always bad. If a block is being executed right away (UIView animate block for example) there is generally no risk.
The problem arises when self captures a block strongly and the block in turn captures self strongly. In this case self retains the block and the block retains self so neither can be released --> retain cycle!
To avoid this you need to capture self weakly in the block.
__weak typeof(self) = self; // CREATE A WEAK REFERENCE OF SELF
__block BOOL blockDoItemsDownload = doItemsDownload; // USE THIS INSTEAD OF REFERENCING ENVIRONMENT VARIABLE DIRECTLY
__block BOOL blockCheckConnection = checkConnection;
internetReachableFoo.reachableBlock = ^(Reachability*reach)
{
// Update the UI on the main thread
dispatch_async(dispatch_get_main_queue(), ^{
NSLog(#"Connessione ad Internet disponibile");
blockCheckConnection = YES;
if(!lastConnectionState)
{
lastConnectionState = YES;
if(blockDoItemsDownload) // Use block variable here
[weakSelf displayChoice]; // Use weakSelf in place of self
}
});
};

Answer 2

There is a cocoapod called libextobjc and what it allows you to do is quickly and cleanly weakify and strongify objects.
#weakify(self)
[someblock:^{
#strongify(self)
}];
As long as you handle self you should be ok. I'm not 100% sure the BOOL values aren't an issue but I think you could do something like this:
BOOL x = YES;
#weakify(self, x)
[someblock:^{
#strongify(self, x)
}];