feat(engine): add type reflection fn for casting to dyn Any

1 files changed, 28 insertions, 2 deletions

diff --git a/engine-reflection/src/lib.rs b/engine-reflection/src/lib.rs
index 289989c..600c511 100644
--- a/engine-reflection/src/lib.rs
+++ b/engine-reflection/src/lib.rs
@@ -1,7 +1,9 @@
 use std::alloc::Layout;
 use std::any::{type_name, Any, TypeId};
 use std::borrow::Cow;
+use std::ffi::c_void;
 use std::fmt::Debug;
+use std::ptr::NonNull;
 
 /// Trait implemented by types that support runtime reflection on them.
 ///
@@ -87,6 +89,18 @@ impl Type
             Self::Array(_) | Self::Slice(_) | Self::Reference(_) => false,
         }
     }
+
+    #[inline]
+    pub fn cast_dyn_any(&self, ptr: NonNull<c_void>) -> Option<NonNull<dyn Any>> {
+        match self {
+            Self::Struct(struct_type) => Some((struct_type.cast_dyn_any)(ptr)),
+            Self::Enum(enum_type) => Some((enum_type.cast_dyn_any)(ptr)),
+            Self::Literal(literal_type) => Some((literal_type.cast_dyn_any)(ptr)),
+            Self::Array(array_type) => Some((array_type.cast_dyn_any)(ptr)),
+            Self::Reference(ref_type) => Some((ref_type.cast_dyn_any)(ptr)),
+            Self::Slice(_) => None
+        }
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -94,6 +108,7 @@ pub struct Struct
 {
     pub fields: &'static [Field],
     pub get_default_value: fn() -> Option<DefaultValueFn>,
+    pub cast_dyn_any: CastDynAnyFn
 }
 
 impl Struct
@@ -125,6 +140,7 @@ pub struct Enum
     pub tagged_union: Option<EnumTaggedUnion>,
 
     pub get_default_value: fn() -> Option<DefaultValueFn>,
+    pub cast_dyn_any: CastDynAnyFn
 }
 
 impl Enum
@@ -232,6 +248,7 @@ pub struct Array
     pub item_layout: Layout,
     pub get_item_type_name: FnWithDebug<&'static str>,
     pub length: usize,
+    pub cast_dyn_any: CastDynAnyFn
 }
 
 impl Array
@@ -267,6 +284,7 @@ pub struct Literal
     pub ty: LiteralType,
     pub type_name: fn() -> &'static str,
     pub get_default_value: fn() -> Option<DefaultValueFn>,
+    pub cast_dyn_any: CastDynAnyFn
 }
 
 impl Literal
@@ -288,6 +306,7 @@ impl Literal
 pub struct Reference
 {
     pub ty: &'static Type,
+    pub cast_dyn_any: CastDynAnyFn
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -339,7 +358,8 @@ macro_rules! impl_reflection_for_literals {
                     type_id: TypeId::of::<$literal>(),
                     ty: LiteralType::$literal_type,
                     type_name: || type_name::<$literal>(),
-                    get_default_value: || Some(|| Box::new(Self::default()))
+                    get_default_value: || Some(|| Box::new(Self::default())),
+                    cast_dyn_any: |ptr| ptr.cast::<Self>()
                 });
             }
         )*
@@ -372,6 +392,7 @@ unsafe impl<T: Reflection, const LEN: usize> Reflection for [T; LEN]
         item_layout: Layout::new::<T>(),
         get_item_type_name: FnWithDebug::new(|| type_name::<T>()),
         length: LEN,
+        cast_dyn_any: |ptr| ptr.cast::<Self>()
     });
 }
 
@@ -386,7 +407,10 @@ unsafe impl<T: Reflection> Reflection for &'static [T]
 
 unsafe impl<T: Reflection> Reflection for &'static T
 {
-    const TYPE_REFLECTION: &Type = &Type::Reference(Reference { ty: T::TYPE_REFLECTION });
+    const TYPE_REFLECTION: &Type = &Type::Reference(Reference {
+        ty: T::TYPE_REFLECTION,
+        cast_dyn_any: |ptr| ptr.cast::<Self>()
+    });
 }
 
 #[derive(Clone)]
@@ -420,3 +444,5 @@ impl<Value: Debug> Debug for FnWithDebug<Value>
 }
 
 type DefaultValueFn = fn() -> Box<dyn Any>;
+
+type CastDynAnyFn = fn(NonNull<c_void>) -> NonNull<dyn Any>;