Execute block on dealloc

NSObject+TUBlockDealloc.h

//
//  NSObject+TUBlockDealloc.h
//  ThinkGV
//
//  Created by David Beck on 4/20/12.
//  Copyright (c) 2012 ThinkUltimate LLC. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface NSObject (TUBlockDealloc)

- (void)executeOnDealloc:(void(^)(void))block;

@end

NSObject+TUBlockDealloc.m

//
//  NSObject+TUBlockDealloc.m
//  ThinkGV
//
//  Created by David Beck on 4/20/12.
//  Copyright (c) 2012 ThinkUltimate LLC. All rights reserved.
//

#import "NSObject+TUBlockDealloc.h"

#import <objc/runtime.h>


const void *TUBlockDeallocExecuterKey = &TUBlockDeallocExecuterKey;


@interface _TUBlockExecuter : NSObject

- (void)addBlock:(void(^)(void))block;

@end

@implementation _TUBlockExecuter
{
	NSMutableArray *_deallocBlocks;
}

- (void)dealloc
{
	for (void(^block)(void) in _deallocBlocks) {
		block();
	}
}

- (id)init
{
    self = [super init];
    if (self) {
        _deallocBlocks = [[NSMutableArray alloc] init];
    }
	
    return self;
}

- (void)addBlock:(void(^)(void))block
{
	[_deallocBlocks addObject:[block copy]];
}

@end


@implementation NSObject (TUBlockDealloc)

- (void)executeOnDealloc:(void(^)(void))block
{
	_TUBlockExecuter *executer = objc_getAssociatedObject(self, TUBlockDeallocExecuterKey);
	if (executer == nil) {
		executer = [[_TUBlockExecuter alloc] init];
		objc_setAssociatedObject(self, TUBlockDeallocExecuterKey, executer, OBJC_ASSOCIATION_RETAIN);
	}
	
	[executer addBlock:block];
}

@end

This works because associated objects are removed when the host object is deallocated. As long as the executer is only referenced by the host object, it will be dealloced at the same time, causing it to execute all of its blocks.