- Remove GodotFuncMarshal

- Rename VariantMetadata -> GodotMetadata
- Add GodotCompatible, ToGodot, FromGodot
- Add RawGd
- Change everything so that To/FromGodot is the canonical way of passing values over the ffi-boundary
- Change `GodotMetadata` to sealed `GodotType`
- Implement `GodotType` for various types
- Add `GodotFfiVariant`
- Add tests for creating newtype wrappers around godot types
- Fix to/from variant derives

Author: lilizoey

godot-codegen/src/central_generator.rs

@@ -397,7 +397,7 @@ fn make_sys_code(central_items: &CentralItems) -> TokenStream {
     let [opaque_32bit, opaque_64bit] = opaque_types;
 
     quote! {
-        use crate::{ffi_methods, GDExtensionTypePtr, GDExtensionVariantOperator, GDExtensionVariantType, GodotFfi};
+        use crate::{GDExtensionVariantOperator, GDExtensionVariantType};
 
         #[cfg(target_pointer_width = "32")]
         pub mod types {
@@ -443,12 +443,6 @@ fn make_sys_code(central_items: &CentralItems) -> TokenStream {
             }
         }
 
-        // SAFETY:
-        // This type is represented as `Self` in Godot, so `*mut Self` is sound.
-        unsafe impl GodotFfi for VariantType {
-            ffi_methods! { type GDExtensionTypePtr = *mut Self; .. }
-        }
-
         // ----------------------------------------------------------------------------------------------------------------------------------------------
 
         #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
@@ -475,12 +469,6 @@ fn make_sys_code(central_items: &CentralItems) -> TokenStream {
                 self as _
             }
         }
-
-        // SAFETY:
-        // This type is represented as `Self` in Godot, so `*mut Self` is sound.
-        unsafe impl GodotFfi for VariantOperator {
-            ffi_methods! { type GDExtensionTypePtr = *mut Self; .. }
-        }
     }
 }
 

godot-codegen/src/class_generator.rs

@@ -1062,7 +1062,8 @@ fn make_special_builtin_methods(class_name: &TyName, _ctx: &Context) -> TokenStr
     if class_name.godot_ty == "Array" {
         quote! {
             pub fn from_outer_typed<T>(outer: &Array<T>) -> Self
-                where T: crate::builtin::meta::VariantMetadata
+                where
+                    T: crate::builtin::meta::GodotType
             {
                 Self {
                     _outer_lifetime: std::marker::PhantomData,

godot-codegen/src/util.rs

@@ -334,21 +334,22 @@ pub fn make_enum_definition(enum_: &Enum) -> TokenStream {
         }
         #index_enum_impl
 
-        impl sys::GodotFuncMarshal for #enum_name {
+        impl crate::builtin::meta::GodotCompatible for #enum_name {
             type Via = i64;
-            type FromViaError = sys::PrimitiveConversionError<i64, i32>;
-            type IntoViaError = std::convert::Infallible;
+        }
 
-            fn try_from_via(via: Self::Via) -> std::result::Result<Self, Self::FromViaError> {
-                let err = sys::PrimitiveConversionError::new(via);
-                let ord = i32::try_from(via).map_err(|_| err)?;
-                <Self as crate::obj::EngineEnum>::try_from_ord(ord).ok_or(err)
+        impl crate::builtin::meta::ToGodot for #enum_name {
+            fn to_godot(&self) -> Self::Via {
+                <Self as crate::obj::EngineEnum>::ord(*self) as i64
+            }
         }
 
-            fn try_into_via(self) -> std::result::Result<Self::Via, Self::IntoViaError> {
-                Ok(<Self as crate::obj::EngineEnum>::ord(self).into())
+        impl crate::builtin::meta::FromGodot for #enum_name {
+            fn try_from_godot(via: Self::Via) -> Option<Self> {
+                <Self as crate::obj::EngineEnum>::try_from_ord(i32::try_from(via).ok()?)
             }
         }
+
         #bitfield_ops
     }
 }

godot-core/src/builtin/aabb.rs

@@ -10,6 +10,8 @@ use sys::{ffi_methods, GodotFfi};
 use crate::builtin::math::ApproxEq;
 use crate::builtin::{real, Plane, Vector3, Vector3Axis};
 
+use super::meta::impl_godot_as_self;
+
 /// Axis-aligned bounding box in 3D space.
 ///
 /// `Aabb` consists of a position, a size, and several utility functions. It is typically used for
@@ -396,9 +398,15 @@ impl std::fmt::Display for Aabb {
 // SAFETY:
 // This type is represented as `Self` in Godot, so `*mut Self` is sound.
 unsafe impl GodotFfi for Aabb {
+    fn variant_type() -> sys::VariantType {
+        sys::VariantType::Aabb
+    }
+
     ffi_methods! { type sys::GDExtensionTypePtr = *mut Self; .. }
 }
 
+impl_godot_as_self!(Aabb);
+
 impl ApproxEq for Aabb {
     /// Returns `true` if the two `Aabb`s are approximately equal, by calling `is_equal_approx` on
     /// `position` and `size`.