BRPickerViewMacro 中 weakify 和 strongify 与其他库重复定义

[codingiran]

#ifndef weakify
    #if DEBUG
        #if __has_feature(objc_arc)
            #define weakify(object) autoreleasepool{} __weak __typeof__(object) weak##_##object = object;
        #else
            #define weakify(object) autoreleasepool{} __block __typeof__(object) block##_##object = object;
        #endif
    #else
        #if __has_feature(objc_arc)
            #define weakify(object) try{} @finally{} {} __weak __typeof__(object) weak##_##object = object;
        #else
            #define weakify(object) try{} @finally{} {} __block __typeof__(object) block##_##object = object;
        #endif
    #endif
#endif

#ifndef strongify
    #if DEBUG
        #if __has_feature(objc_arc)
            #define strongify(object) autoreleasepool{} __typeof__(object) object = weak##_##object;
        #else
            #define strongify(object) autoreleasepool{} __typeof__(object) object = block##_##object;
        #endif
    #else
        #if __has_feature(objc_arc)
            #define strongify(object) try{} @finally{} __typeof__(object) object = weak##_##object;
        #else
            #define strongify(object) try{} @finally{} __typeof__(object) object = block##_##object;
        #endif
    #endif
#endif

weakify 和 strongify 是个非常常见的便捷生成__weak __typeof(self)weakSelf = self 和 __strong __typeof(weakSelf)strongSelf = weakSelf的宏定义，很多库都会有类似定义。

建议这类公共方法留给用户自己去定义，或者直接在 podspec 引用最早提出这个写法的 libextobjc：pod 'libextobjc/EXTScope'