Question

假设我有两个类和两个这样的函数：

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)
}

在someSuperContainer返回之前subFunc保证有效吗？或者在subFunc输入后它会被释放，因为它不再被引用了？

修改更好的例子（我试图保持问题的通用性，但现在我认为包含一个真实世界的例子更好）：

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

在范围结束之前，任何变量或类都可用并且处于活动状态。在您的情况下，someSuperContainer的范围为superFunc。当superFunc结束时，someSuperContainer也将如此。

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

财产访问期间的ARC生命周期

1 个答案: