Return Option<jobject> about jni-rs

[dbrgn]

Ah, this seems to work:

ptr::null_mut() as *mut _jobject

Maybe that could somehow be made more ergonomic? Via an Option would be fantastic, but even a provided helper function creating such a null-jobject would be nice.

[jrobsonchase]

Do you mean that you're trying to return either a jobject or a null pointer from an extern "C" function? I think that the "Option to represent a null ffi pointer" pattern is mainly used for function pointers. I'm pretty sure that returning an Option to C-land doesn't work in the same manner, so it won't be possible to do that here. A helper should be pretty easy though.

[dbrgn]

Do you mean that you're trying to return either a jobject or a null pointer from an extern "C" function?

Exactly. In Java it would be something like this:

public MyObject foo() {
    if (...) {
        return new MyObject();
    } else {
        return null;
    }
}

[jrobsonchase]

Going ahead and closing this since I'm like 95% sure that returning an option from an FFI function is not and likely will never be possible, and the helper for constructing a null object made its way into 0.6.1.

If you can find anything to the contrary on the option return, feel free to reopen!

[dbrgn]

Would something like that work? llogiq/optional#23