macOS捆绑包之间的双向数据交换（快速） [英] Bidirectional data exchange between macOS Bundles (swift)

问题描述

如何在macOS捆绑包之间传递数据？

How can I pass data between macOS Bundles?

例如：MyApp.app将数据发送到MyBundle.bundle中的函数或类初始化程序，后者执行自己的逻辑在上面。甚至可以返回一个值，然后MyApp.app可以对其进行进一步处理。

eg: MyApp.app sends data to a function or class initialiser in MyBundle.bundle, which performs its own logic on it. It could even return a value, which MyApp.app can then process further.

例如，MyBundle中的一个函数（未嵌套在任何其他声明中）：

Fo example, a function in MyBundle (not nested in any other declaration):

    void initialise(unsigned int frameCount) {…} // not a class initialiser btw

我已经尝试过：

• 在MyBundle，然后使用 Foundation.Bundle 将其加载到MyApp中：

• Declaring a class in MyBundle and then loading it in MyApp using Foundation.Bundle:

let class = (Bundle(url: url)!.classNamed("MyClass")! as! NSObject.Type).init()
// class is an instance of NSObject, but I can override the `init()` method 
// (in MyBundle) to do whatever. I have not found a way to implement an 
// initialiser with parameters, and it still be recognised here.

在MyBundle中声明一个函数并使用 CFBundleGetFunctionPointerForName

Declaring a function in MyBundle and using CFBundleGetFunctionPointerForName to retrieve it.

var bundles = CFBundleCreateBundlesFromDirectory(kCFAllocatorDefault, bundleDirectory, bundleExtension)! as Array
var bundle1 = bundles.first! as! CFBundle

var untypedFunctionPointer = CFBundleGetFunctionPointerForName(bundle, "initialise" as CFString)!

let imp = unsafeBitCast(untypedFunctionPointer, to: IMP.self)

let function = unsafeBitCast(imp, to: (@convention(c)(CUnsignedInt) -> Void).self)
// If I specify parameters here, pass them in below, then try to use them in my objective c function, I get exc_bad_access.

function(CUnsignedInt(1.0)) // Will work only when not trying to access parameters in the original objective c function.



// Whatever @convention(c) function signature I use, the parameters are unusable in Objective C.

两者的关键问题是我无法将数据作为参数传递。因此，打印语句将起作用，但不能使用参数。

The critical issue with both is that I am unable to pass data in as parameters. So a print statement will work but no ability to use arguments.

编辑：接受的答案显示了调用函数指针的正确方法。我谈论的崩溃是由于使用了无法正确桥接到C语言族的类型而导致的，因此在有疑问时请坚持使用Foundation库中的NSNumber，NSString等。

Edit: Accepted answer shows the correct method for calling function pointers. The crashes I talked about are a result of using types which are not being bridged to the C family of languages properly, so stick to NSNumber, NSString etc. from the Foundation library when in doubt.

推荐答案

根据您的问题从Bundle中调用Swift函数和评论在 https://stackoverflow.com/a/56281093/5329717 中，我想您是在Swift中动态调用函数之后指针或带有 UnsafeBufferPointer 参数的Objective-C方法。

Based on your question Call Swift function from Bundle and comments in https://stackoverflow.com/a/56281093/5329717 I presume you're after dynamically invoking in Swift a function pointer or an objective-c method with UnsafeBufferPointer argument.

首先 UnsafeBufferPointer 将进行复制，以便进行互操作，我建议改用 OpaquePointer 。

First of all UnsafeBufferPointer will make a copy so for interoping I recommend switching to OpaquePointer instead.

假定函数指向带有签名 void cFunction（void * arg）的指针大小写：

Assuming function to pointer case with signature void cFunction(void* arg):

let fakeIMP = unsafeBitCast(functionToPointerAddress, to: IMP.self)
unsafeBitCast(fakeIMP,to:(@convention(c)(OpaquePointer)->Void).self)(bufferArg)

假定静态objective-c方法：

Assuming static objective-c method:

let receiverClass = NSClassFromString("SomeClass")
let selector: Selector = NSSelectorFromString("selectorArg:")
let methodIMP: IMP! = method_getImplementation(class_getClassMethod(receiverClass, selector))
unsafeBitCast(methodIMP,to:(@convention(c)(AnyClass?,Selector,OpaquePointer)->Any).self)(receiverClass,selector, bufferArg)

对于您提供的C签名

void initialise(unsigned int frameCount);

尝试一下：

let imp = unsafeBitCast(functionToPointerAddress, to: IMP.self)
unsafeBitCast(imp,to:(@convention(c)(Int)->Void).self)(1)

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