roundtrip working for the first time

python/pyarrow/serialization.pxi

@@ -71,19 +71,40 @@ def deserialize_sequence(PythonObject value, object base):
 def write_python_object(PythonObject value, NativeFile sink):
     cdef shared_ptr[OutputStream] stream
     sink.write_handle(&stream)
-    cdef shared_ptr[CRecordBatchFileWriter] writer
+    cdef shared_ptr[CRecordBatchStreamWriter] writer
     cdef shared_ptr[CSchema] schema = deref(value.batch).schema()
     cdef shared_ptr[CRecordBatch] batch = value.batch
     cdef shared_ptr[CTensor] tensor
     cdef int32_t metadata_length
     cdef int64_t body_length
 
     with nogil:
-        check_status(CRecordBatchFileWriter.Open(stream.get(), schema, &writer))
+        check_status(CRecordBatchStreamWriter.Open(stream.get(), schema, &writer))
         check_status(deref(writer).WriteRecordBatch(deref(batch)))
         check_status(deref(writer).Close())
 
     for tensor in value.tensors:
         check_status(WriteTensor(deref(tensor), stream.get(), &metadata_length, &body_length))
 
-# def read_python_object(NativeFile source):
+def read_python_object(NativeFile source):
+    cdef PythonObject result = PythonObject()
+    cdef shared_ptr[RandomAccessFile] stream
+    source.read_handle(&stream)
+    cdef shared_ptr[CRecordBatchStreamReader] reader
+    cdef shared_ptr[CTensor] tensor
+    cdef int64_t offset
+
+    with nogil:
+        check_status(CRecordBatchStreamReader.Open(<shared_ptr[InputStream]> stream, &reader))
+        check_status(reader.get().ReadNextRecordBatch(&result.batch))
+
+        check_status(deref(stream).Tell(&offset))
+
+        while True:
+            s = ReadTensor(offset, stream.get(), &tensor)
+            result.tensors.push_back(tensor)
+            if not s.ok():
+                break
+            check_status(deref(stream).Tell(&offset))
+
+    return result

python/pyarrow/tests/test_serialization.py

@@ -0,0 +1,44 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import os
+
+import pyarrow as pa
+import numpy as np
+
+obj = pa.lib.serialize_sequence([np.array([1, 2, 3]), None, np.array([4, 5, 6])])
+
+SIZE = 4096
+arr = np.random.randint(0, 256, size=SIZE).astype('u1')
+data = arr.tobytes()[:SIZE]
+path = os.path.join("/tmp/temp")
+with open(path, 'wb') as f:
+    f.write(data)
+
+f = pa.memory_map(path, mode="w")
+
+pa.lib.write_python_object(obj, f)
+
+f = pa.memory_map(path, mode="r")
+
+res = pa.lib.read_python_object(f)
+
+pa.lib.deserialize_sequence(res, res)