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

src/execution.cc

Index: src/execution.cc
diff --git a/src/execution.cc b/src/execution.cc
index ecf2d22f698f31f1893991a70c412479b5b70121..4cb612863a2e0d4b38594683601987aeb147721c 100644
--- a/src/execution.cc
+++ b/src/execution.cc
@@ -136,9 +136,18 @@ MaybeHandle<Object> Execution::Call(Isolate* isolate, Handle<Object> callable,
         handle(Handle<JSGlobalObject>::cast(receiver)->global_proxy(), isolate);
   }
 
+  bool is_callback = false;

[Benedikt Meurer, 2015/11/12 04:31:21]

Please add a TODO here, that this code will need cleanup once we know exactly
what we want in the end.

[epertoso, 2015/11/13 01:39:28]

I refactored the code a bit.

I'm not sure I understand your comment. With this patch, we will have two
possible callbacks: the regular FunctionCallback, and the 'fast' one which is
passed around as a code object. Do you foresee any way in which this might
change?

+  if (callable->IsJSFunction()) {
+    Handle<JSFunction> function = Handle<JSFunction>::cast(callable);
+    if (function->shared()->IsApiFunction()) {
+      Object* call_code = function->shared()->get_api_func_data()->call_code();
+      is_callback = call_code->IsCallHandlerInfo() &&
+                    !CallHandlerInfo::cast(call_code)->callback()->IsCode();
+    }
+  }
+
   // api callbacks can be called directly.
-  if (callable->IsJSFunction() &&
-      Handle<JSFunction>::cast(callable)->shared()->IsApiFunction()) {
+  if (is_callback) {
     Handle<JSFunction> function = Handle<JSFunction>::cast(callable);
     SaveContext save(isolate);
     isolate->set_context(function->context());