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Avoid Strong Reference Cycles when Capturing self

Blocks in objective C are really awesome...but...

If you need to capture self in a block, such as when defining a callback block, it’s important to consider the memory management implications.

Blocks maintain strong references to any captured objects, including self, which means that it’s easy to end up with a strong reference cycle if, for example, an object maintains a copy property for a block that captures self:

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@interface TechClass : NSObject
@property (copy) void (^block)(void);
@end

@implementation TechClass
- (void)configureBlock {
    self.block = ^{
        [self doWork];    // capturing a strong reference to self
                               // creates a strong reference cycle
    };
}
@end

To avoid this retain cycle we have to do changes as below  


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- (void)configureBlock {
    TechClass * __weak weakSelf = self;
    self.block = ^{
        [weakSelf doWork];   // capture the weak reference
                                  // to avoid the reference cycle
    }
}

This change makes sure that retain cycle is not created for self.
You can check all these scenario in sample code @ Sample Code
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