Now that QtJniTypes::Objects are no longer primitive types that are the
same as a jobject, using those types in registered native functions
breaks. JNI will call those function with a jobject on the function
pointer, and lacking any type safety, the call to the registered
function will proceed with a wrong type of object on the stack.
To fix that, register the native function via a proxy that is a variadic
argument function, and unpack the variadic arguments into a list of
typed arguments, using the types we know the user-code function wants.
Then call the function with a tuple of those types using std::apply,
which gives us type safety and implicit conversion for free.
Add a test that exercises this.
Change-Id: I9f980e55d3d13f8fc16c410dc0d17dbdc200cb47
Reviewed-by: Juha Vuolle <juha.vuolle@qt.io>
185c3b080c