From 073dd3642e1d7d0755a2d492f8e78b7544831daf Mon Sep 17 00:00:00 2001
From: Philipp Moritz <pcmoritz@gmail.com>
Date: Fri, 3 Jun 2016 12:11:30 -0700
Subject: [PATCH] implement none serialization

---
 protos/types.proto | 5 +++++
 src/orchpylib.cc   | 4 ++++
 test/runtest.py    | 3 +++
 3 files changed, 12 insertions(+)

diff --git a/protos/types.proto b/protos/types.proto
index 6b08478e6..ee730a6c4 100644
--- a/protos/types.proto
+++ b/protos/types.proto
@@ -12,6 +12,10 @@ message Double {
 	double data = 1;
 }
 
+// Empty used to represent a None object
+message Empty {
+}
+
 message PyObj {
   bytes data = 1;
 }
@@ -25,6 +29,7 @@ message Obj {
   List list_data = 4;
   Dict dict_data = 8;
   Array array_data = 5;
+  Empty empty_data = 9;
   PyObj pyobj_data = 6;
 }
 
diff --git a/src/orchpylib.cc b/src/orchpylib.cc
index 9c2e0b92d..da16655ad 100644
--- a/src/orchpylib.cc
+++ b/src/orchpylib.cc
@@ -231,6 +231,8 @@ int serialize(PyObject* worker_capsule, PyObject* val, Obj* obj, std::vector<Obj
     Py_ssize_t length;
     PyString_AsStringAndSize(val, &buffer, &length); // creates pointer to internal buffer
     obj->mutable_string_data()->set_data(buffer, length);
+  } else if (val == Py_None) {
+    obj->mutable_empty_data(); // allocate an Empty object, this is a None
   } else if (PyArray_Check(val)) {
     PyArrayObject* array = PyArray_GETCONTIGUOUS((PyArrayObject*) val);
     Array* data = obj->mutable_array_data();
@@ -347,6 +349,8 @@ PyObject* deserialize(PyObject* worker_capsule, const Obj& obj, std::vector<ObjR
     const char* buffer = obj.string_data().data().data();
     Py_ssize_t length = obj.string_data().data().size();
     return PyString_FromStringAndSize(buffer, length);
+  } else if (obj.has_empty_data()) {
+    Py_RETURN_NONE;
   } else if (obj.has_array_data()) {
     const Array& array = obj.array_data();
     std::vector<npy_intp> dims;
diff --git a/test/runtest.py b/test/runtest.py
index f6440327f..02e71a803 100644
--- a/test/runtest.py
+++ b/test/runtest.py
@@ -38,6 +38,9 @@ class SerializationTest(unittest.TestCase):
     self.roundTripTest(w, "hello world")
     self.roundTripTest(w, 42.0)
     self.roundTripTest(w, (1.0, "hi"))
+    self.roundTripTest(w, None)
+    self.roundTripTest(w, (None, None))
+    self.roundTripTest(w, ("hello", None))
 
     self.roundTripTest(w, {"hello" : "world", 1: 42, 1.0: 45})
     self.roundTripTest(w, {})