stream_base: various improvements

Expose and use in TLSWrap an `v8::External` wrap of the
`StreamBase*` pointer instead of guessing the ancestor C++ class in
`node_wrap.h`.

Make use of `StreamBase::Callback` structure for storing/passing both
callback and context in a single object.

Introduce `GetObject()` for future user-land usage, when a child class
is not going to be inherited from AsyncWrap.

PR-URL: https://github.com/nodejs/node/pull/2351
Reviewed-By: Trevor Norris <trev.norris@gmail.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/src/stream_base-inl.h b/src/stream_base-inl.h
index d74b47de60..dd0bbcfbd8 100644
--- a/src/stream_base-inl.h
+++ b/src/stream_base-inl.h
@@ -10,6 +10,7 @@
 
 namespace node {
 
+using v8::External;
 using v8::FunctionCallbackInfo;
 using v8::FunctionTemplate;
 using v8::Handle;
@@ -36,6 +37,13 @@ void StreamBase::AddMethods(Environment* env,
                                      v8::DEFAULT,
                                      attributes);
 
+  t->InstanceTemplate()->SetAccessor(env->external_stream_string(),
+                                     GetExternal<Base>,
+                                     nullptr,
+                                     env->as_external(),
+                                     v8::DEFAULT,
+                                     attributes);
+
   env->SetProtoMethod(t, "readStart", JSMethod<Base, &StreamBase::ReadStart>);
   env->SetProtoMethod(t, "readStop", JSMethod<Base, &StreamBase::ReadStop>);
   if ((flags & kFlagNoShutdown) == 0)
@@ -72,6 +80,16 @@ void StreamBase::GetFD(Local<String> key,
 }
 
 
+template <class Base>
+void StreamBase::GetExternal(Local<String> key,
+                             const PropertyCallbackInfo<Value>& args) {
+  StreamBase* wrap = Unwrap<Base>(args.Holder());
+
+  Local<External> ext = External::New(args.GetIsolate(), wrap);
+  args.GetReturnValue().Set(ext);
+}
+
+
 template <class Base,
           int (StreamBase::*Method)(const FunctionCallbackInfo<Value>& args)>
 void StreamBase::JSMethod(const FunctionCallbackInfo<Value>& args) {