如何分配->发送->收到->演员->将UnsafeRawPointer从扩展名分配到应用程序? [英] How to allocate -> send -> receive -> cast -> deallocate UnsafeRawPointer from extension to app?

问题描述

我是UnsafeRawPointer的新手. 如我所知，我需要在扩展程序中分配不安全的内存，并将指针发送到我的应用程序，该应用程序必须进行强制转换和释放. 以下是我想做的草图. 我想从Safari扩展程序发送string message并通过CFNotificationCenterGetDarwinNotifyCenter在应用程序中接收它，该怎么做?

I am new in UnsafeRawPointer. As I got I need to allocate unsafe memory in my extension and send pointer to my app where has to cast and release it. Below is a sketch of what I want to do. I'd like to send a string message from Safari extension and receive it in app by CFNotificationCenterGetDarwinNotifyCenter, how to do it?

let center = CFNotificationCenterGetDarwinNotifyCenter()

CFNotificationCenterAddObserver(center, nil, { (_, observer, name, message, _) -> Void in
    //message as String???             
}, Self.action, nil, .deliverImmediately)

var message = "some text"
CFNotificationCenterPostNotification(center, .init(action), message, nil, true)

主要问题?

• 发送字符串使用哪种类型?
• 如何正确分配内存?
• 如何在观察者中将其转换为String?
• 如何正确释放内存?

Main questions?

• What type use to send String?
• How to allocate memory right?
• How to cast it to String in observer?
• How to deallocate memory right?

推荐答案

感谢@MartinR，我得到了所有有关我问题的答案.

Thanks @MartinR, I got all answers on my questions.

我们无法通过CFNotificationCenterPostNotification发送对象，因此我们需要使用Darwin和UserDefaults(suitename:)组合.

We can't send an object though CFNotificationCenterPostNotification so we need to use Darwin and UserDefaults(suitename:) combination.

1. 在应用程序代码
在应用程序
1. Add the CFNotificationCenterAddObserver observer in the app code
2. Save sending object in UserDefaults(suitename:)
3. Send the didObjectChanged notification through CFNotificationCenterPostNotification code
4. Catch didObjectChanged notification in CFNotificationCallback in the app code
5. Read sending object from UserDefaults(suitename:)

题外话

问题?为什么使用UnsafeRawPointer?

Off-topic

Question Why do we use UnsafeRawPointer? sample

答案 CFNotificationCenterPostNotification实际上是一个C function，并且回调也是一个纯C function. C对Swift types或instance pointers一无所知.这就是为什么object参数是UnsafeRawPointer(与void *等效的Swift)的原因.

Answer CFNotificationCenterPostNotification is actually a C function, and the callback is also a pure C function. C knows nothing about Swift types or instance pointers. That's why the object parameter is a UnsafeRawPointer (the Swift equivalent of void *).

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