Adds the possibility of setting a Code object as the callback of a FunctionTemplate.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 23829034ebd69561afd7ccb2f81cd57c5ff64a6f..8203614ef27f4b42afdc951e1c3beb2bed4aa7ce 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -996,7 +996,8 @@ void FunctionTemplate::Inherit(v8::Local<FunctionTemplate> value) {
 
 
 static Local<FunctionTemplate> FunctionTemplateNew(
-    i::Isolate* isolate, FunctionCallback callback, v8::Local<Value> data,
+    i::Isolate* isolate, FunctionCallback callback,
+    v8::Local<Value> fast_handler, v8::Local<Value> data,
     v8::Local<Signature> signature, int length, bool do_not_cache) {
   i::Handle<i::Struct> struct_obj =
       isolate->factory()->NewStruct(i::FUNCTION_TEMPLATE_INFO_TYPE);
@@ -1014,7 +1015,7 @@ static Local<FunctionTemplate> FunctionTemplateNew(
     if (data.IsEmpty()) {
       data = v8::Undefined(reinterpret_cast<v8::Isolate*>(isolate));
     }
-    Utils::ToLocal(obj)->SetCallHandler(callback, data);
+    Utils::ToLocal(obj)->SetCallHandler(callback, data, fast_handler);
   }
   obj->set_length(length);
   obj->set_undetectable(false);
@@ -1025,6 +1026,7 @@ static Local<FunctionTemplate> FunctionTemplateNew(
   return Utils::ToLocal(obj);
 }
 
+
 Local<FunctionTemplate> FunctionTemplate::New(Isolate* isolate,
                                               FunctionCallback callback,
                                               v8::Local<Value> data,
@@ -1036,8 +1038,22 @@ Local<FunctionTemplate> FunctionTemplate::New(Isolate* isolate,
   DCHECK(!i_isolate->serializer_enabled());
   LOG_API(i_isolate, "FunctionTemplate::New");
   ENTER_V8(i_isolate);
-  return FunctionTemplateNew(
-      i_isolate, callback, data, signature, length, false);
+  return FunctionTemplateNew(i_isolate, callback, v8::Local<Value>(), data,
+                             signature, length, false);
+}
+
+
+Local<FunctionTemplate> FunctionTemplate::NewWithFastHandler(
+    Isolate* isolate, FunctionCallback callback, v8::Local<Value> fast_handler,
+    v8::Local<Value> data, v8::Local<Signature> signature, int length) {
+  // TODO(vogelheim): 'fast_handler' should have a more specific type than
+  // Local<Value>.
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  DCHECK(!i_isolate->serializer_enabled());
+  LOG_API(i_isolate, "FunctionTemplate::NewWithFastHandler");
+  ENTER_V8(i_isolate);
+  return FunctionTemplateNew(i_isolate, callback, fast_handler, data, signature,
+                             length, false);
 }
 
 
@@ -1095,7 +1111,8 @@ int TypeSwitch::match(v8::Local<Value> value) {
 
 
 void FunctionTemplate::SetCallHandler(FunctionCallback callback,
-                                      v8::Local<Value> data) {
+                                      v8::Local<Value> data,
+                                      v8::Local<Value> fast_handler) {
   auto info = Utils::OpenHandle(this);
   EnsureNotInstantiated(info, "v8::FunctionTemplate::SetCallHandler");
   i::Isolate* isolate = info->GetIsolate();
@@ -1106,6 +1123,11 @@ void FunctionTemplate::SetCallHandler(FunctionCallback callback,
   i::Handle<i::CallHandlerInfo> obj =
       i::Handle<i::CallHandlerInfo>::cast(struct_obj);
   SET_FIELD_WRAPPED(obj, set_callback, callback);
+  if (!fast_handler.IsEmpty()) {
+    i::Handle<i::Object> code = Utils::OpenHandle(*fast_handler);
+    CHECK(code->IsCode());
+    obj->set_fast_handler(*code);
+  }
   if (data.IsEmpty()) {
     data = v8::Undefined(reinterpret_cast<v8::Isolate*>(isolate));
   }
@@ -4368,8 +4390,9 @@ MaybeLocal<Function> Function::New(Local<Context> context,
   i::Isolate* isolate = Utils::OpenHandle(*context)->GetIsolate();
   LOG_API(isolate, "Function::New");
   ENTER_V8(isolate);
-  return FunctionTemplateNew(isolate, callback, data, Local<Signature>(),
-                             length, true)->GetFunction(context);
+  return FunctionTemplateNew(isolate, callback, Local<Value>(), data,
+                             Local<Signature>(), length, true)
+      ->GetFunction(context);
 }