Fiber* Fiber::current(STATE) {
#ifdef RBX_FIBER_ENABLED
Fiber* fib = state->vm()->current_fiber.get();
// Lazily allocate a root fiber.
if(fib->nil_p()) {
fib = state->memory()->new_object<Fiber>(state, G(fiber));
fib->root(true);
fib->status(Fiber::eRunning);
fib->data(state->vm()->new_fiber_data(true, fib->stack_size()->to_native()));
fib->data()->set_call_frame(state->vm()->call_frame());
state->memory()->native_finalizer(state, fib,
(memory::FinalizerFunction)&Fiber::finalize);
state->vm()->current_fiber.set(fib);
state->vm()->root_fiber.set(fib);
}
return fib;
#else
Exception::raise_not_implemented_error(state, "Fibers not supported on this platform");
#endif
}
Object* Fiber::s_yield(STATE, Arguments& args) {
#ifdef RBX_FIBER_ENABLED
Fiber* cur = Fiber::current(state);
Fiber* dest_fib = cur->prev();
assert(cur != dest_fib);
if(cur->root()) {
Exception::raise_fiber_error(state, "can't yield from root fiber");
}
cur->prev(state, nil<Fiber>());
Array* val = args.as_array(state);
dest_fib->value(state, val);
cur->sleep(state);
dest_fib->run(state);
dest_fib->data()->switch_to(state, cur->data());
// Back here when someone yields back to us!
// Beware here, because the GC has probably run so GC pointers on the C++ stack
// can't be accessed.
cur = Fiber::current(state);
Array* ret = cur->value();
if(ret->nil_p()) return cNil;
switch(ret->size()) {
case 0: return cNil;
case 1: return ret->get(state, 0);
default: return ret;
}
#else
Exception::raise_not_implemented_error(state, "Fibers not supported on this platform");
#endif
}