util,src: allow lookup of hidden values

This commit adds an internal util method that makes hidden
values in the C++ layer visible in JS.

PR-URL: https://github.com/nodejs/node/pull/3988
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

1 files changed, 19 insertions, 0 deletions

diff --git a/src/node_util.cc b/src/node_util.cc
index 19c3e3240a..a520b8d5f3 100644
--- a/src/node_util.cc
+++ b/src/node_util.cc
@@ -10,6 +10,7 @@ using v8::Context;
 using v8::FunctionCallbackInfo;
 using v8::Local;
 using v8::Object;
+using v8::String;
 using v8::Value;
 
 static void IsMapIterator(const FunctionCallbackInfo<Value>& args) {
@@ -28,6 +29,23 @@ static void IsPromise(const FunctionCallbackInfo<Value>& args) {
   args.GetReturnValue().Set(args[0]->IsPromise());
 }
 
+
+static void GetHiddenValue(const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+
+  if (!args[0]->IsObject())
+    return env->ThrowTypeError("obj must be an object");
+
+  if (!args[1]->IsString())
+    return env->ThrowTypeError("name must be a string");
+
+  Local<Object> obj = args[0].As<Object>();
+  Local<String> name = args[1].As<String>();
+
+  args.GetReturnValue().Set(obj->GetHiddenValue(name));
+}
+
+
 void Initialize(Local<Object> target,
                 Local<Value> unused,
                 Local<Context> context) {
@@ -35,6 +53,7 @@ void Initialize(Local<Object> target,
   env->SetMethod(target, "isMapIterator", IsMapIterator);
   env->SetMethod(target, "isSetIterator", IsSetIterator);
   env->SetMethod(target, "isPromise", IsPromise);
+  env->SetMethod(target, "getHiddenValue", GetHiddenValue);
 }
 
 }  // namespace util