add v8::ReturnValue (#66)

src/function.cc

@@ -39,4 +39,11 @@ void v8__FunctionCallbackInfo__SetReturnValue(v8::FunctionCallbackInfo<v8::Value
   auto rv = self->GetReturnValue();
   rv.Set(value);
 }
+
+v8::ReturnValue<v8::Value> *v8__FunctionCallbackInfo__GetReturnValue(v8::FunctionCallbackInfo<v8::Value> *self)
+{
+  v8::ReturnValue<v8::Value>* return_value = nullptr;
+  *return_value = self->GetReturnValue();
+  return return_value;
+}
 }

src/function.rs

@@ -1,6 +1,7 @@
 use crate::isolate::{CxxIsolate, LockedIsolate};
 use crate::support::{int, Opaque};
 use crate::Context;
+use crate::HandleScope;
 use crate::Local;
 use crate::Value;
 
@@ -34,6 +35,32 @@ extern "C" {
     info: &FunctionCallbackInfo,
     value: *mut Value,
   );
+  fn v8__FunctionCallbackInfo__GetReturnValue(
+    info: &FunctionCallbackInfo,
+  ) -> ReturnValue<Value>;
+}
+
+#[repr(C)]
+pub struct ReturnValue<T>(T, Opaque);
+
+impl <T>ReturnValue<T> {
+  // NOTE: simplest setter, possibly we'll need to add
+  // more setters specialized per type
+  pub fn set<U>(&self, _value: Local<'_, U>) {
+    unimplemented!();
+  }
+
+  /// Convenience getter for Isolate
+  pub fn get_isolate(&self) -> &mut CxxIsolate {
+    unimplemented!();
+  }
+
+  /// Getter. Creates a new Local<> so it comes with a certain performance
+  /// hit. If the ReturnValue was not yet set, this will return the undefined
+  /// value.
+  pub fn get<'sc>(&self, _scope: &mut HandleScope<'sc>) -> Local<'sc, Value> {
+    unimplemented!();
+  }
 }
 
 #[repr(C)]
@@ -44,6 +71,10 @@ impl FunctionCallbackInfo {
     unsafe { v8__FunctionCallbackInfo__SetReturnValue(&*self, &mut *value) };
   }
 
+  pub fn get_return_value(&self) -> ReturnValue<Value> {
+    unsafe { v8__FunctionCallbackInfo__GetReturnValue(&*self) }
+  }
+
   pub fn get_isolate(&self) -> &mut CxxIsolate {
     unsafe { v8__FunctionCallbackInfo__GetIsolate(self) }
   }

src/local.rs

@@ -1,8 +1,8 @@
+use crate::value::Value;
 use std::marker::PhantomData;
 use std::ops::Deref;
 use std::ops::DerefMut;
 use std::ptr::NonNull;
-use crate::value::Value;
 
 pub struct Local<'sc, T>(NonNull<T>, PhantomData<&'sc ()>);
 
@@ -33,7 +33,7 @@ impl<'sc, T> DerefMut for Local<'sc, T> {
   }
 }
 
-// TODO make it possible for targets other than Local<Value>. For example 
+// TODO make it possible for targets other than Local<Value>. For example
 // Local<String> should be able to be down cast to Local<Name>.
 impl<'sc, T> From<Local<'sc, T>> for Local<'sc, Value>
 where

src/number.rs

@@ -3,9 +3,9 @@ use std::ops::Deref;
 use crate::isolate::CxxIsolate;
 use crate::isolate::LockedIsolate;
 use crate::support::Opaque;
+use crate::value::Value;
 use crate::HandleScope;
 use crate::Local;
-use crate::value::Value;
 
 extern "C" {
   fn v8__Number__New(isolate: &mut CxxIsolate, value: f64) -> *mut Number;