refactor(python): Split ArrowArray and ArrowArrayStream modules (#559)

This is the final splitting of modules from `_lib.pyx`, which no longer
exists! It separates the array stream and array components to live in
separate .pyx files and adds basic docstrings to internal functions. It
also removes a few references to `_lib` and `c_lib` that had made it
through to this PR.

python/setup.py

@@ -136,8 +136,11 @@ def nanoarrow_extension(
         nanoarrow_extension(
             "nanoarrow._device", nanoarrow_c=True, nanoarrow_device=True
         ),
+        nanoarrow_extension(
+            "nanoarrow._array", nanoarrow_c=True, nanoarrow_device=True
+        ),
+        nanoarrow_extension("nanoarrow._array_stream", nanoarrow_c=True),
         nanoarrow_extension("nanoarrow._buffer", nanoarrow_c=True),
-        nanoarrow_extension("nanoarrow._lib", nanoarrow_c=True, nanoarrow_device=True),
         nanoarrow_extension("nanoarrow._ipc_lib", nanoarrow_c=True, nanoarrow_ipc=True),
         nanoarrow_extension("nanoarrow._schema", nanoarrow_c=True),
     ],

python/src/nanoarrow/__init__.py

@@ -87,7 +87,6 @@
     "c_array_from_buffers",
     "c_array_stream",
     "c_buffer",
-    "c_lib",
     "c_schema",
     "c_version",
     "date32",

python/src/nanoarrow/_array.pxd

@@ -0,0 +1,55 @@
+# 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.
+
+# cython: language_level = 3
+
+from libc.stdint cimport int64_t
+
+from nanoarrow_c cimport (
+    ArrowArray,
+    ArrowArrayView,
+)
+
+from nanoarrow_device_c cimport (
+    ArrowDeviceArray,
+    ArrowDeviceType
+)
+
+from nanoarrow._device cimport Device
+from nanoarrow._schema cimport CSchema
+
+
+cdef class CArray:
+    cdef object _base
+    cdef ArrowArray* _ptr
+    cdef CSchema _schema
+    cdef ArrowDeviceType _device_type
+    cdef int _device_id
+
+    cdef _set_device(self, ArrowDeviceType device_type, int64_t device_id)
+
+
+cdef class CArrayView:
+    cdef object _base
+    cdef object _array_base
+    cdef ArrowArrayView* _ptr
+    cdef Device _device
+
+cdef class CDeviceArray:
+    cdef object _base
+    cdef ArrowDeviceArray* _ptr
+    cdef CSchema _schema