stubs for handling Series, DataFrame more efficiently by default in serialization code paths

Change-Id: I7f57a0c49d1f2adf7087254a035869e461251a03

python/pyarrow/pandas_compat.py

@@ -526,3 +526,15 @@ def _add_any_metadata(table, pandas_metadata):
         return pa.Table.from_arrays(columns)
     else:
         return table
+
+
+_default_serialization_context.register_type(
+    pd.Series, 'pandas.Series',
+    custom_serializer=_serialize_series,
+    custom_deserializer=_deserialize_series)
+
+
+_default_serialization_context.register_type(
+    pd.DataFrame, 'pandas.DataFrame',
+    custom_serializer=_serialize_dataframe,
+    custom_deserializer=_deserialize_dataframe)

python/pyarrow/serialization.pxi

@@ -137,6 +137,10 @@ cdef class SerializationContext:
                     obj.__dict__.update(serialized_obj)
         return obj
 
+
+_default_serialization_context = SerializationContext()
+
+
 cdef class SerializedPyObject:
     """
     Arrow-serialized representation of Python object
@@ -174,6 +178,9 @@ cdef class SerializedPyObject:
         """
         cdef PyObject* result
 
+        if context is None:
+            context = _default_serialization_context
+
         with nogil:
             check_status(DeserializeObject(context, self.data,
                                            <PyObject*> self.base, &result))
@@ -210,6 +217,10 @@ def serialize(object value, SerializationContext context=None):
     """
     cdef SerializedPyObject serialized = SerializedPyObject()
     wrapped_value = [value]
+
+    if context is None:
+        context = _default_serialization_context
+
     with nogil:
         check_status(SerializeObject(context, wrapped_value, &serialized.data))
     return serialized