ios - 如何在不进入无限循环的情况下调配 NSError init

Question

swizzling时如何调用原来的NSError init方法？

我目前的实现

 extension NSError {

    @objc class func errorSwizzle() {
        guard let instance = class_getInstanceMethod(self, #selector(NSError.init(domain:code:userInfo:))),
            let swizzleInstance = class_getInstanceMethod(self, #selector(NSError.init(swizzleDomain:code:info:))) else { return }
        method_exchangeImplementations(instance, swizzleInstance)
    }

    @objc class func errorUnSwizzle() {
        guard let instance = class_getInstanceMethod(self, #selector(NSError.init(domain:code:userInfo:))),
            let swizzleInstance = class_getInstanceMethod(self, #selector(NSError.init(swizzleDomain:code:info:))) else { return }
        method_exchangeImplementations(swizzleInstance, instance)
    }

    @objc convenience init(swizzleDomain: String, code: Int, info: [String : Any]?) {

        /// infinite loop as it calls the swizzled init again.
        self.init(domain: swizzleDomain, code: code, userInfo: info)

        /// Do something.. 
    }
}

Answer 1

你已经交换了实现，这意味着你必须调用:

@objc convenience init(swizzleDomain: String, code: Int, info: [String : Any]?) {
    self.init(swizzleDomain: swizzleDomain, code: code, info: info)
}

因为 self.init(swizzleDomain:...) 将包含原始初始化程序。