Working

crates/luaffi/src/option.rs

@@ -1,4 +1,4 @@
-use crate::{CDef, CDefBuilder, FromFfi, ToFfi, Type, TypeBuilder, display};
+use crate::{CDef, CDefBuilder, FfiReturnConvention, FromFfi, ToFfi, Type, TypeBuilder, display};
 use std::{ffi::c_int, fmt::Display, ptr};
 
 #[repr(C)]
@@ -29,34 +29,32 @@ unsafe impl<T: Type> CDef for lua_option<T> {
 }
 
 unsafe impl<T: FromFfi> FromFfi for Option<T> {
-    type From = *mut Self::FromValue; // pass by-ref
-    type FromValue = lua_option<T::FromValue>;
+    type From = lua_option<T::From>;
+    type FromArg = *mut Self::From; // pass by-ref
 
-    const ARG_KEEPALIVE: bool = T::ARG_KEEPALIVE;
+    fn require_keepalive() -> bool {
+        T::require_keepalive()
+    }
 
     fn prelude(arg: &str) -> impl Display {
-        let ct = Self::FromValue::name();
+        let ct = Self::From::name();
         display!(
-            "if {arg} == nil then {arg} = {ct}(); else {}{arg} = {ct}(1, {arg}); end; ",
+            "if {arg} == nil then {arg} = __cnew(__ctypes.{ct}); else {}{arg} = __cnew(__ctypes.{ct}, 1, {arg}); end; ",
             T::prelude(arg)
         )
     }
 
     fn convert(from: Self::From) -> Self {
-        debug_assert!(
-            !from.is_null(),
-            "Option<T>::convert() called on a null lua_option<T>"
-        );
-
-        Self::convert_value(unsafe { ptr::replace(from, lua_option::None) })
-    }
-
-    fn convert_value(from: Self::FromValue) -> Self {
         match from {
-            lua_option::Some(value) => Some(T::convert_value(value)),
+            lua_option::Some(value) => Some(T::convert(value)),
             lua_option::None => None,
         }
     }
+
+    fn convert_arg(from: Self::FromArg) -> Self {
+        debug_assert!(!from.is_null());
+        Self::convert(unsafe { ptr::replace(from, lua_option::None) })
+    }
 }
 
 unsafe impl<T: ToFfi> ToFfi for Option<T> {
@@ -69,12 +67,12 @@ unsafe impl<T: ToFfi> ToFfi for Option<T> {
         }
     }
 
-    fn postlude(ret: &str) -> impl Display {
+    fn postlude(ret: &str, _conv: FfiReturnConvention) -> impl Display {
         // if we don't have a value, return nil. otherwise copy out the inner value immediately,
         // forget the option cdata, then call postlude on the inner value.
         display!(
             "if {ret}.__tag == 0 then {ret} = nil; else {ret} = {ret}.__value; {}end; ",
-            T::postlude(ret)
+            T::postlude(ret, FfiReturnConvention::ByValue)
         )
     }
 }