iOS Proper Use of @weakify(self) and @strongify(self)

Question

I\'m starting to integrate libextobjc (https://github.com/jspahrsummers/libextobjc) into my iOS application primarily to take advantage of EXTScope\'s @strongify an

Answer 1

Calling "self" inside the block that in hold by "self" will lead to "Retain Cycles" and hence memory leaks. So ideally it goes like:

@interface A: NSObject // Some interface A

@property (nonatomic, copy, readwrite) dispatch_block_t someBlock; // See block is strongly retained here.

@end

*******************************************************
@implementation A

- (void) someAPI
{
    __weak A * weakSelf = self; // Assign self to weakSelf and use it
    // enter code here inside block to break retain cycles.
    self.someBlock = 
    ^{
        A * strongSelf = weakSelf; // Assign weak self to strongSelf before
       // using it. This is because weakSelf can go nil anytime and it may happen
       // that only few lines from block get executed before weakSelf goes nil,
       // and hence code may be in some bad state.
        if (strongSelf != nil)
        {
            // Use strongSelf.
            [strongSelf doSomethingAwesome];
            [strongSelf doSomethingAwesomeAgain];
        }
    };
}

@end

If the block is not retained by "self", then its safe to just use "self" inside blocks and they won't create retain-cycles.

Note: Memory management concept remains same with use of "libextobjc" library.