feat: implement ResourceAny -> Resource<T> conversion

crates/wasmtime/src/component/resources.rs

@@ -397,6 +397,32 @@ where
         })
     }
 
+    /// Attempts to convert a [`ResourceAny`] into [`Resource`].
+    pub fn try_from_resource_any(
+        ResourceAny { idx, ty, own_state }: ResourceAny,
+        mut store: impl AsContextMut,
+    ) -> Result<Self> {
+        let store = store.as_context_mut();
+        let store_id = store.0.id();
+        let mut tables = host_resource_tables(store.0);
+        assert_eq!(ty, ResourceType::host::<T>(), "resource type mismatch");
+        let (state, rep) = if let Some(OwnState { store, dtor, flags }) = own_state {
+            assert_eq!(store_id, store, "wrong store used to convert resource");
+            assert!(dtor.is_some(), "destructor must be set");
+            assert!(flags.is_none(), "flags must not be set");
+            let rep = tables.resource_lift_own(None, idx)?;
+            (AtomicU32::new(NOT_IN_TABLE), rep)
+        } else {
+            let rep = tables.resource_lift_borrow(None, idx)?;
+            (AtomicU32::new(BORROW), rep)
+        };
+        Ok(Resource {
+            state,
+            rep,
+            _marker: marker::PhantomData,
+        })
+    }
+
     /// See [`ResourceAny::try_from_resource`]
     pub fn try_into_resource_any<U>(
         self,
@@ -568,6 +594,11 @@ impl ResourceAny {
         })
     }
 
+    /// See [`Resource::try_from_resource_any`]
+    pub fn try_into_resource<T: 'static>(self, store: impl AsContextMut) -> Result<Resource<T>> {
+        Resource::try_from_resource_any(self, store)
+    }
+
     /// Returns the corresponding type associated with this resource, either a
     /// host-defined type or a guest-defined type.
     ///

tests/all/component_model/resources.rs

@@ -582,6 +582,15 @@ fn dynamic_val() -> Result<()> {
     match &results[0] {
         Val::Resource(resource) => {
             assert_eq!(resource.ty(), ResourceType::host::<MyType>());
+            assert!(resource.owned());
+
+            let resource = resource.try_into_resource::<MyType>(&mut store)?;
+            assert_eq!(resource.rep(), 100);
+            assert!(resource.owned());
+
+            let resource = resource.try_into_resource_any(&mut store, &i_pre, idx)?;
+            assert_eq!(resource.ty(), ResourceType::host::<MyType>());
+            assert!(resource.owned());
         }
         _ => unreachable!(),
     }
@@ -593,21 +602,46 @@ fn dynamic_val() -> Result<()> {
     match &results[0] {
         Val::Resource(resource) => {
             assert_eq!(resource.ty(), ResourceType::host::<MyType>());
+            assert!(resource.owned());
+
+            let resource = resource.try_into_resource::<MyType>(&mut store)?;
+            assert_eq!(resource.rep(), 100);
+            assert!(resource.owned());
+
+            let resource = resource.try_into_resource_any(&mut store, &i_pre, idx)?;
+            assert_eq!(resource.ty(), ResourceType::host::<MyType>());
+            assert!(resource.owned());
         }
         _ => unreachable!(),
     }
 
-    let t1 = Resource::new_own(100);
+    let t1 = Resource::<MyType>::new_own(100)
+        .try_into_resource_any(&mut store, &i_pre, idx)?
+        .try_into_resource(&mut store)?;
     let (t1,) = a_typed_result.call(&mut store, (t1,))?;
     a_typed_result.post_return(&mut store)?;
+    assert_eq!(t1.rep(), 100);
+    assert!(t1.owned());
 
-    let t1_any = t1.try_into_resource_any(&mut store, &i_pre, idx)?;
+    let t1_any = t1
+        .try_into_resource_any(&mut store, &i_pre, idx)?
+        .try_into_resource::<MyType>(&mut store)?
+        .try_into_resource_any(&mut store, &i_pre, idx)?;
     let mut results = [Val::Bool(false)];
     a.call(&mut store, &[Val::Resource(t1_any)], &mut results)?;
     a.post_return(&mut store)?;
     match &results[0] {
         Val::Resource(resource) => {
             assert_eq!(resource.ty(), ResourceType::host::<MyType>());
+            assert!(resource.owned());
+
+            let resource = resource.try_into_resource::<MyType>(&mut store)?;
+            assert_eq!(resource.rep(), 100);
+            assert!(resource.owned());
+
+            let resource = resource.try_into_resource_any(&mut store, &i_pre, idx)?;
+            assert_eq!(resource.ty(), ResourceType::host::<MyType>());
+            assert!(resource.owned());
         }
         _ => unreachable!(),
     }