From 21f3f145eb4e9d6312e91cc507be4afb4bde7081 Mon Sep 17 00:00:00 2001
From: Wodann <wodannson@gmail.com>
Date: Wed, 29 Apr 2020 00:43:47 +0200
Subject: [PATCH] feat(runtime): add cloning of StructRef

---
 crates/mun_runtime/src/struct.rs        |  1 +
 crates/mun_runtime/tests/marshalling.rs | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/crates/mun_runtime/src/struct.rs b/crates/mun_runtime/src/struct.rs
index d140746b4..7d88082ea 100644
--- a/crates/mun_runtime/src/struct.rs
+++ b/crates/mun_runtime/src/struct.rs
@@ -27,6 +27,7 @@ impl RawStruct {
 
 /// Type-agnostic wrapper for interoperability with a Mun struct.
 /// TODO: Handle destruction of `struct(value)`
+#[derive(Clone)]
 pub struct StructRef {
     handle: GcRootPtr,
     runtime: Rc<RefCell<Runtime>>,
diff --git a/crates/mun_runtime/tests/marshalling.rs b/crates/mun_runtime/tests/marshalling.rs
index c83218df6..6af996738 100644
--- a/crates/mun_runtime/tests/marshalling.rs
+++ b/crates/mun_runtime/tests/marshalling.rs
@@ -430,6 +430,27 @@ fn marshal_struct() {
     test_shallow_copy(&mut foo, &foo2, &int_data, "a");
     test_shallow_copy(&mut foo, &foo2, &bool_data, "b");
 
+    fn test_clone<
+        T: Copy + std::fmt::Debug + PartialEq + ArgumentReflection + ReturnTypeReflection,
+    >(
+        s1: &mut StructRef,
+        s2: &StructRef,
+        data: &TestData<T>,
+        field_name: &str,
+    ) {
+        assert_eq!(s1.get::<T>(field_name), s2.get::<T>(field_name));
+        s1.set(field_name, data.1).unwrap();
+        assert_eq!(s1.get::<T>(field_name), s2.get::<T>(field_name));
+        s1.replace(field_name, data.0).unwrap();
+        assert_eq!(s1.get::<T>(field_name), s2.get::<T>(field_name));
+    }
+
+    // Verify that StructRef::clone returns a `StructRef` to the same memory
+    let mut foo = baz.get::<StructRef>("0").unwrap();
+    let foo2 = foo.clone();
+    test_clone(&mut foo, &foo2, &int_data, "a");
+    test_clone(&mut foo, &foo2, &bool_data, "b");
+
     let mut bar = qux.get::<StructRef>("0").unwrap();
 
     // Specify invalid return type