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[manuelbl]

👋 Welcome!

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[Tnze]

Thanks for this wonderful project!

I think this is the most modern solution to calling Win32 APIs from Java nowadays. And it is so worth promoting.

I’m working on a project trying to offer the perfect IME support (as the goal) on Windows for Minecraft as a Fabric MOD. And I tried writing JNI in C++ at first, and the development experience just sucks. Turn to use this project makes things elegant a lot.

There’s a personal comment here: may be we can generate a higher level binding here? Just like what Microsoft did for Rust. There are windows-sys for low-level binding and windows for high-level binding. Can we do the same thing for Java?

[manuelbl]

I'm glad the project is useful for you.

While much better than what jextract produces for Windows APIs, the result is still quite low level. I fully agree. I have thought about a higher level binding but have not yet cracked it. Good ideas are welcome, especially with regards to memory management and complex data structures.

[Tnze]

There's some thinking about COM objects lifetime managements.

Basic idea is to provide an Stub class with implementations of IUknown, which use reflections inside QueryInterface. We list all COM interfaces current class implemented in the constructor, and cache theirs IIDs and create corresponding pointers with correct vtables.

public class IUnknownStub implements IUnknown {
    private Map<Guide, MemorySegment> pointers = ...;

    public IUnknownStub() {
        // for (Class i : getClass().getInterfaces()) { ... }
    }

    public MemorySegments QueryInterface(Guid iid) {
        //...
        MemodySegment pointer = pointers.get(iid);
        if (pointer != null) {
            AddRef();
            return pointer;
        }
        //...
    }

    //...
}

---

The problem is how to implement the reference counting. I think we should provide at least two versions of the Stub.

One use a global Arena inside and somehow grantees a strong reference is hold when RC number greater than zero.

And the other use a confined or shared Arena, and expose AutoClosable to users. (Or just let the user decide what arena to be use?)

---

A key designing decision is -- should java user manually operating AddRef and Release? If true, just use a confined arena inside and close the arena when rc number decreased to zero.