wasmtime-c-api: Remove nested options from wasm_ref_t representation

crates/c-api/src/ref.rs

@@ -7,7 +7,7 @@ use wasmtime::{ExternRef, Func, Val};
 /// `*mut wasm_ref_t` is a reference type (`externref` or `funcref`), as seen by
 /// the C API. Because we do not have a uniform representation for `funcref`s
 /// and `externref`s, a `*mut wasm_ref_t` is morally a
-/// `Option<Box<Either<Option<ExternRef>, Option<Func>>>>`.
+/// `Option<Box<Either<ExternRef, Func>>>`.
 ///
 /// A null `*mut wasm_ref_t` is either a null `funcref` or a null `externref`
 /// depending on context (e.g. the table's element type that it is going into or
@@ -23,8 +23,8 @@ pub struct wasm_ref_t {
 
 #[derive(Clone)]
 pub(crate) enum WasmRefInner {
-    ExternRef(Option<ExternRef>),
+    ExternRef(ExternRef),
-    FuncRef(Option<Func>),
+    FuncRef(Func),
 }
 
 wasmtime_c_api_macros::declare_own!(wasm_ref_t);
@@ -35,40 +35,40 @@ pub(crate) fn ref_into_val(r: Option<Box<wasm_ref_t>>) -> Option<Val> {
     let r = r?;
 
     Some(match r.r {
-        WasmRefInner::ExternRef(x) => Val::ExternRef(x),
+        WasmRefInner::ExternRef(x) => Val::ExternRef(Some(x)),
-        WasmRefInner::FuncRef(x) => Val::FuncRef(x),
+        WasmRefInner::FuncRef(f) => Val::FuncRef(Some(f)),
     })
 }
 
 pub(crate) fn ref_to_val(r: &wasm_ref_t) -> Val {
     match &r.r {
-        WasmRefInner::ExternRef(x) => Val::ExternRef(x.clone()),
+        WasmRefInner::ExternRef(x) => Val::ExternRef(Some(x.clone())),
-        WasmRefInner::FuncRef(x) => Val::FuncRef(x.clone()),
+        WasmRefInner::FuncRef(f) => Val::FuncRef(Some(f.clone())),
     }
 }
 
 pub(crate) fn val_into_ref(val: Val) -> Option<Box<wasm_ref_t>> {
     match val {
-        Val::ExternRef(x) => Some(Box::new(wasm_ref_t {
+        Val::ExternRef(Some(x)) => Some(Box::new(wasm_ref_t {
             r: WasmRefInner::ExternRef(x),
         })),
-        Val::FuncRef(x) => Some(Box::new(wasm_ref_t {
+        Val::FuncRef(Some(f)) => Some(Box::new(wasm_ref_t {
-            r: WasmRefInner::FuncRef(x),
+            r: WasmRefInner::FuncRef(f),
         })),
         _ => None,
     }
 }
 
 #[no_mangle]
-pub extern "C" fn wasm_ref_copy(r: &wasm_ref_t) -> Box<wasm_ref_t> {
+pub extern "C" fn wasm_ref_copy(r: Option<&wasm_ref_t>) -> Option<Box<wasm_ref_t>> {
-    Box::new(r.clone())
+    r.map(|r| Box::new(r.clone()))
 }
 
 #[no_mangle]
-pub extern "C" fn wasm_ref_same(a: &wasm_ref_t, b: &wasm_ref_t) -> bool {
+pub extern "C" fn wasm_ref_same(a: Option<&wasm_ref_t>, b: Option<&wasm_ref_t>) -> bool {
-    match (&a.r, &b.r) {
+    match (a.map(|a| &a.r), b.map(|b| &b.r)) {
-        (WasmRefInner::ExternRef(Some(a)), WasmRefInner::ExternRef(Some(b))) => a.ptr_eq(b),
+        (Some(WasmRefInner::ExternRef(a)), Some(WasmRefInner::ExternRef(b))) => a.ptr_eq(b),
-        (WasmRefInner::ExternRef(None), WasmRefInner::ExternRef(None)) => true,
+        (None, None) => true,
         // Note: we don't support equality for `Func`, so we always return
         // `false` for `funcref`s.
         _ => false,
@@ -76,19 +76,19 @@ pub extern "C" fn wasm_ref_same(a: &wasm_ref_t, b: &wasm_ref_t) -> bool {
 }
 
 #[no_mangle]
-pub extern "C" fn wasm_ref_get_host_info(_ref: &wasm_ref_t) -> *mut c_void {
+pub extern "C" fn wasm_ref_get_host_info(_ref: Option<&wasm_ref_t>) -> *mut c_void {
     std::ptr::null_mut()
 }
 
 #[no_mangle]
-pub extern "C" fn wasm_ref_set_host_info(_ref: &wasm_ref_t, _info: *mut c_void) {
+pub extern "C" fn wasm_ref_set_host_info(_ref: Option<&wasm_ref_t>, _info: *mut c_void) {
     eprintln!("`wasm_ref_set_host_info` is not implemented");
     std::process::abort();
 }
 
 #[no_mangle]
 pub extern "C" fn wasm_ref_set_host_info_with_finalizer(
-    _ref: &wasm_ref_t,
+    _ref: Option<&wasm_ref_t>,
     _info: *mut c_void,
     _finalizer: Option<extern "C" fn(*mut c_void)>,
 ) {

crates/c-api/src/val.rs

@@ -78,7 +78,13 @@ impl wasm_val_t {
                 kind: from_valtype(&ValType::F64),
                 of: wasm_val_union { u64: f },
             },
-            Val::ExternRef(r) => wasm_val_t {
+            Val::ExternRef(None) => wasm_val_t {
+                kind: from_valtype(&ValType::ExternRef),
+                of: wasm_val_union {
+                    ref_: ptr::null_mut(),
+                },
+            },
+            Val::ExternRef(Some(r)) => wasm_val_t {
                 kind: from_valtype(&ValType::ExternRef),
                 of: wasm_val_union {
                     ref_: Box::into_raw(Box::new(wasm_ref_t {
@@ -86,7 +92,13 @@ impl wasm_val_t {
                     })),
                 },
             },
-            Val::FuncRef(f) => wasm_val_t {
+            Val::FuncRef(None) => wasm_val_t {
+                kind: from_valtype(&ValType::FuncRef),
+                of: wasm_val_union {
+                    ref_: ptr::null_mut(),
+                },
+            },
+            Val::FuncRef(Some(f)) => wasm_val_t {
                 kind: from_valtype(&ValType::FuncRef),
                 of: wasm_val_union {
                     ref_: Box::into_raw(Box::new(wasm_ref_t {