Handling foreign structure pointers returned from a function call

First of all, thank you for starting this awesome project!

I'm currently working on a service using WebKitGTK+ (It's WebKit1 interface) and I faced with the problem of JavaScriptCore GTK bindings which simply do not exist. As there is gir file describing two foreign structures - JavaScriptCore.GlobalContext and JavaScriptCore.Value - I decided to try to use LuaJIT's FFI to operate with this structures directly.

So, I'm calling web_view:get_main_frame():get_global_context() to get JSGlobalContextRef but the returning pointer value is slightly different from the value returned by direct FFI call ffi.C.webkit_web_frame_get_global_context(web_view:get_main_frame()._native). It looks like JavaScriptCore.GlobalContext is boxed but I'm unable to find a proper way to unbox it. I've already tried some GValue magic but it seems I'm doing it wrong. Here is what I always get:

cdata<struct OpaqueJSContext *>: 0x7fb0dc1df9b0
lgi.rec 0x7ffc9c0d1bf0:JavaScriptCore.GlobalContext

What is the recommended way to handle foreign pointers in this case?

Start by reproducing the mismatch between get_global_context() and ffi.C.webkit_web_frame_get_global_context(web_view:get_main_frame()._native) using the WebKitGTK WebKit1 calls described in the issue. Inspect how lgi represents JavaScriptCore.GlobalContext and JavaScriptCore.Value foreign structures; done means establishing and documenting a supported way to handle the returned pointers.