fix ctypes bug for mac (#9)

* fix c_api bug for mac

* update travis

.travis.yml

@@ -4,7 +4,7 @@ language: cpp
 
 os:
   - linux
-  #  - osx
+  - osx
 
 env:
   # code analysis

python/tvm/_ctypes/_api.py

@@ -25,8 +25,13 @@ kDouble = 2
 kStr = 3
 kNodeHandle = 4
 
+NODE_TYPE = {
+}
 
-def _type_key(handle):
+def _return_node(x):
+    handle = x.v_handle
+    if not isinstance(handle, ctypes.c_void_p):
+        handle = ctypes.c_void_p(handle)
     ret_val = ArgVariant()
     ret_typeid = ctypes.c_int()
     ret_success = ctypes.c_int()
@@ -35,17 +40,14 @@ def _type_key(handle):
         ctypes.byref(ret_val),
         ctypes.byref(ret_typeid),
         ctypes.byref(ret_success)))
-    return py_str(ret_val.v_str)
-
-NODE_TYPE = {
-}
+    return NODE_TYPE.get(py_str(ret_val.v_str), NodeBase)(handle)
 
 RET_SWITCH = {
     kNull: lambda x: None,
     kLong: lambda x: x.v_long,
     kDouble: lambda x: x.v_double,
     kStr: lambda x: py_str(x.v_str),
-    kNodeHandle: lambda x: NODE_TYPE.get(_type_key(x), NodeBase)(x.v_handle)
+    kNodeHandle: lambda x: _return_node(x)
 }
 
 class SliceBase(object):