如何在 Swift 中调用 IMP？

Question

由于 Swift2 你可以使用好的 ole'：

class_getMethodImplementation(cls: AnyClass!, _ name: Selector) -> IMP

它返回imp。在Objective-C 你可以这样称呼它：

implementation(self, selector)

但是如何在 Swift 中调用它呢？

Answer 1

根据文章Instance Methods are Curried Functions in Swift，很容易达到预期的结果：

typealias MyCFunction = @convention(c) (AnyObject, Selector) -> Void
let curriedImplementation = unsafeBitCast(implementation, MyCFunction.self)
curriedImplementation(self, selector)

Answer 2

我试图让运行时调用对带有参数的实例方法起作用。 @Fabio 的回答让我大部分时间都在那里。以下是未来谷歌员工的完整示例：

import Foundation

class X {
  @objc func sayHiTo(name: String) {
    print("Hello \(name)!")
  }
}

let obj = X()
let sel = #selector(obj.sayHiTo)
let meth = class_getInstanceMethod(object_getClass(obj), sel)
let imp = method_getImplementation(meth)

typealias ClosureType = @convention(c) (AnyObject, Selector, String) -> Void
let sayHiTo : ClosureType = unsafeBitCast(imp, ClosureType.self)
sayHiTo(obj, sel, "Fabio")
// prints "Hello Fabio!"