swift - 属性访问期间的 ARC 生命周期

Question

假设我有两个类和两个函数，如下所示:

public class DataContainer {
    let someData = NSMutableData()
}
public class SuperContainer {
    let someDataContainer = DataContainer()
}

func subFunc(someDataContainer: DataContainer) {
    // Is someSuperContainer guaranteed to be alive?
    // Or may it have been released and only someDataContainer is still alive,
    //    because someSuperContainer is not referenced anymore? 

    ... do something with someDataContainer ...
}
func superFunc() {
    let someSuperContainer = SuperContainer()
    subFunc(someSuperContainer.someDataContainer)
}

someSuperContainer 是否保证在 subFunc 返回之前一直存在，或者它可能会在 subFunc 输入后因为不再被引用而被释放？

---

编辑: 更好的例子(我试图让问题保持通用，但现在我认为最好包括一个真实世界的例子):

public class DataContainer {
    let someData = NSMutableData()
    deinit {
        memset_s(someData.mutableBytes, someData.length, 0x00, someData.length)
    }
}

func doSomethingWithData(data: NSMutableData) {
    // Is DataContainer guaranteed to be still alive?
    // Or may it have been released and `data` zeroed-out,
    //    because someSuperContainer is not referenced anymore
    //    (and was deinitialized and released)? 

    ... do something with data ...
}
func someFunc() {
    let dataContainer = DataContainer()
    doSomethingWithData(dataContainer.someData)
}

Answer 1

任何变量或类在其范围结束之前都是可用的和有效的。在您的例子中，someSuperContainer 的范围是 superFunc。当 superFunc 结束时，someSuperContainer 也会结束。

func superFunc() {
    let someSuperContainer = SuperContainer()
    subFunc(someSuperContainer.someDataContainer)
    // someSuperContainer will cease to exist once this func completes.
}