2019-09-03

发现一个有趣的现象，OC 重写get方法，然后调用get方法会导致属性的引用记述不断增加，self.xxx如果和get方法交叉调用，self.xxx输出的引用计数也会不断增加，否则只会比_xxx的引用计数多一。属性若是原子的，那么不重写get方法，计数也会增加

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
//    av_register_all();
    
    
    UIImageView *i = [[UIImageView alloc] init];
    _image = i;
    printf("%ld\n",CFGetRetainCount((__bridge CFTypeRef)_image));
    printf("%ld\n",CFGetRetainCount((__bridge CFTypeRef)_image));

    printf("%ld\n",CFGetRetainCount((__bridge CFTypeRef)([self image])));
    printf("%ld\n",CFGetRetainCount((__bridge CFTypeRef)(self.image)));
    printf("%ld\n",CFGetRetainCount((__bridge CFTypeRef)(self.image)));
    NSLog(@"change");
    printf("%ld\n",CFGetRetainCount((__bridge CFTypeRef)([self image])));
    printf("%ld\n",CFGetRetainCount((__bridge CFTypeRef)([self image])));
    printf("%ld\n",CFGetRetainCount((__bridge CFTypeRef)(self.image)));
    printf("%ld\n",CFGetRetainCount((__bridge CFTypeRef)(((UIImageView* (*) (id, SEL)) objc_msgSend) (self, sel_registerName("image")))));
}
- (UIImageView *)image{
    NSLog(@"%s",__func__);
    return _image;
}