feat(op2): #[cppgc] return values (#672)

Author: littledivy

core/runtime/ops.rs

@@ -1854,10 +1854,9 @@ mod tests {
   }
 
   #[op2]
-  pub fn op_test_make_cppgc_resource<'s>(
-    scope: &'s mut v8::HandleScope,
-  ) -> v8::Local<'s, v8::Object> {
-    crate::cppgc::make_cppgc_object(scope, TestResource { value: 42 })
+  #[cppgc]
+  pub fn op_test_make_cppgc_resource() -> TestResource {
+    TestResource { value: 42 }
   }
 
   #[op2(fast)]

ops/op2/dispatch_fast.rs

@@ -876,7 +876,8 @@ fn map_retval_to_v8_fastcall_type(
     | Arg::V8Local(_)
     | Arg::OptionV8Local(_)
     | Arg::OptionV8Global(_)
-    | Arg::OptionV8Ref(..) => return Ok(None),
+    | Arg::OptionV8Ref(..)
+    | Arg::CppGcResource(..) => return Ok(None),
     Arg::Buffer(..) | Arg::OptionBuffer(..) => return Ok(None),
     Arg::External(..) => V8FastCallType::Pointer,
     _ => return Err("a fast return value"),

ops/op2/dispatch_slow.rs

@@ -715,6 +715,10 @@ pub fn return_value_infallible(
     ArgMarker::Number => {
       gs_quote!(generator_state(result) => (deno_core::_ops::RustToV8Marker::<deno_core::_ops::NumberMarker, _>::from(#result)))
     }
+    ArgMarker::Cppgc => {
+      generator_state.needs_scope = true;
+      gs_quote!(generator_state(scope, result) => (deno_core::v8::Local::<deno_core::v8::Value>::from(deno_core::cppgc::make_cppgc_object(&mut #scope, #result))))
+    }
     ArgMarker::None => gs_quote!(generator_state(result) => (#result)),
   };
   let res = match ret_type.slow_retval() {
@@ -777,6 +781,9 @@ pub fn return_value_v8_value(
     ArgMarker::Number => {
       quote!(deno_core::_ops::RustToV8Marker::<deno_core::_ops::NumberMarker, _>::from(#result))
     }
+    ArgMarker::Cppgc => {
+      quote!(deno_core::cppgc::make_cppgc_object(&mut #scope, #result))
+    }
     ArgMarker::None => quote!(#result),
   };
   let res = match ret_type.slow_retval() {

ops/op2/signature.rs

@@ -476,6 +476,7 @@ impl Arg {
         Arg::OptionBuffer(.., BufferSource::TypedArray) => {
           ArgSlowRetval::V8LocalFalliable
         }
+        Arg::CppGcResource(_) => ArgSlowRetval::V8LocalNoScope,
         _ => ArgSlowRetval::None,
       }
     }
@@ -491,6 +492,7 @@ impl Arg {
       Arg::SerdeV8(_) => ArgMarker::Serde,
       Arg::Numeric(NumericArg::__SMI__, _) => ArgMarker::Smi,
       Arg::Numeric(_, NumericFlag::Number) => ArgMarker::Number,
+      Arg::CppGcResource(_) => ArgMarker::Cppgc,
       _ => ArgMarker::None,
     }
   }
@@ -527,6 +529,8 @@ pub enum ArgMarker {
   Number,
   /// This buffer type should be serialized as an ArrayBuffer.
   ArrayBuffer,
+  /// This type should be wrapped as a cppgc V8 object.
+  Cppgc,
 }
 
 #[derive(Debug)]
@@ -1449,12 +1453,17 @@ fn parse_type_state(ty: &Type) -> Result<Arg, ArgError> {
   Ok(s)
 }
 
-fn parse_cppgc(ty: &Type) -> Result<Arg, ArgError> {
-  match ty {
-    Type::Reference(of) if of.mutability.is_none() => match &*of.elem {
-      Type::Path(of) => Ok(Arg::CppGcResource(stringify_token(&of.path))),
-      _ => Err(ArgError::InvalidCppGcType(stringify_token(ty))),
-    },
+fn parse_cppgc(position: Position, ty: &Type) -> Result<Arg, ArgError> {
+  match (position, ty) {
+    (Position::Arg, Type::Reference(of)) if of.mutability.is_none() => {
+      match &*of.elem {
+        Type::Path(of) => Ok(Arg::CppGcResource(stringify_token(&of.path))),
+        _ => Err(ArgError::InvalidCppGcType(stringify_token(ty))),
+      }
+    }
+    (Position::RetVal, Type::Path(of)) => {
+      Ok(Arg::CppGcResource(stringify_token(&of.path)))
+    }
     _ => Err(ArgError::ExpectedCppGcReference(stringify_token(ty))),
   }
 }
@@ -1469,7 +1478,7 @@ pub(crate) fn parse_type(
 
   if let Some(primary) = attrs.primary {
     match primary {
-      AttributeModifier::CppGcResource => return parse_cppgc(ty),
+      AttributeModifier::CppGcResource => return parse_cppgc(position, ty),
       AttributeModifier::Serde => match ty {
         Type::Tuple(of) => {
           return Ok(Arg::SerdeV8(stringify_token(of)));

ops/op2/test_cases/sync/cppgc_resource.out

@@ -4,3 +4,11 @@ deno_ops_compile_test_runner::prelude!();
 
 #[op2(fast)]
 fn op_file(#[cppgc] _file: &std::fs::File) {}
+
+struct Wrap;
+
+#[op2]
+#[cppgc]
+fn op_make_cppgc_object() -> Wrap {
+    Wrap
+}