class V8::Portal::Interceptor

def initialize(portal, access)
  @to, @access = portal, access
end

def intercept(info, retval = nil, &code)
  obj = @to.rb(info.This())
  intercepts = true
  result = @to.rubyprotect do
    dontintercept = proc do
      intercepts = false
    end
    code.call(obj, dontintercept)
  end
  intercepts ? (retval || result) : C::Empty
end