Extend API to allow setting length property for function templates.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 0a6d25baebb27cc4859918703f7540622f45cf32..4966f9b1d9758eab0ab66641d40460174f8e2e9b 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -1070,6 +1070,7 @@ Local<FunctionTemplate> FunctionTemplate::New(InvocationCallback callback,
     if (data.IsEmpty()) data = v8::Undefined();
     Utils::ToLocal(obj)->SetCallHandler(callback, data);
   }
+  obj->set_length(0);

[Yang, 2012/12/19 09:14:45]

We have this Signature object (third argument in this New-method) where we can
specify the number of arguments. In our repo the Signature object is only used
in test-api.cc, but maybe it makes sense to set the length to the argc (length
of the arg-FixedArray) in Signature?

[rossberg, 2012/12/19 10:21:50]

Interesting idea. But as discussed offline, it's probably preferable to keep
internal type checking (which is what Signature supports) and the rather
arbitrary value of the 'length' property separate concerns.

I added length as an additional optional argument to the New constructor,
though.

   obj->set_undetectable(false);
   obj->set_needs_access_check(false);
 
@@ -1240,6 +1241,14 @@ Local<ObjectTemplate> FunctionTemplate::InstanceTemplate() {
 }
 
 
+void FunctionTemplate::SetLength(int length) {
+  i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
+  if (IsDeadCheck(isolate, "v8::FunctionTemplate::SetLength()")) return;
+  ENTER_V8(isolate);
+  Utils::OpenHandle(this)->set_length(length);
+}
+
+
 void FunctionTemplate::SetClassName(Handle<String> name) {
   i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
   if (IsDeadCheck(isolate, "v8::FunctionTemplate::SetClassName()")) return;