Use _testbuffer instead of a new helper in _ctypes_test

_testbuffer.ndarray already exposes the raw Py_buffer, and it can also
request particular flags, which the buffer_info() helper could not.

Author: serhiy-storchaka

Lib/test/test_ctypes/test_pep3118.py

@@ -1,14 +1,16 @@
 import re
 import sys
 import unittest
-from _ctypes_test import buffer_info
+from test.support import import_helper
 from ctypes import (CFUNCTYPE, POINTER, sizeof, Union,
                     Structure, LittleEndianStructure, BigEndianStructure,
                     c_char, c_byte, c_ubyte,
                     c_short, c_ushort, c_int, c_uint,
                     c_long, c_ulong, c_longlong, c_ulonglong, c_uint64,
                     c_bool, c_float, c_double, c_longdouble, py_object)
 
+_testbuffer = import_helper.import_module('_testbuffer')
+
 
 if sys.byteorder == "little":
     THIS_ENDIAN = "<"
@@ -50,17 +52,43 @@ def test_native_types(self):
             self.assertEqual(n * v.itemsize, len(v.tobytes()))
 
     def test_native_types_shape_strides(self):
-        # check that ctypes (not memoryview) correctly fills out shape and
-        # strides in the buffer protocol
+        # memoryview fills in the shape and the strides which the exporter
+        # does not provide, and always requests all of them, so check what
+        # ctypes exports itself.
         for tp, fmt, shape, stride, itemtp in native_types:
             with self.subTest(tp=tp):
-                v = buffer_info(tp())
-                if v['ndim'] == 0:
-                    self.assertIsNone(v['shape'])
-                    self.assertIsNone(v['strides'])
-                else:
-                    self.assertEqual(v['shape'], shape)
-                    self.assertEqual(v['strides'], stride)
+                v = _testbuffer.ndarray(tp(), getbuf=_testbuffer.PyBUF_FULL_RO)
+                self.assertEqual(v.shape, shape)
+                self.assertEqual(v.strides, stride)
+
+    def test_flags(self):
+        ob = (c_int * 3 * 2)()
+
+        v = _testbuffer.ndarray(ob, getbuf=_testbuffer.PyBUF_SIMPLE)
+        # ndim > 1 implies shape != NULL, so a flat buffer is exported.
+        self.assertEqual(v.ndim, 1)
+        self.assertEqual(v.shape, ())
+        self.assertEqual(v.strides, ())
+
+        v = _testbuffer.ndarray(ob, getbuf=_testbuffer.PyBUF_ND)
+        self.assertEqual(v.shape, (2, 3))
+        self.assertEqual(v.strides, ())
+
+        v = _testbuffer.ndarray(ob, getbuf=_testbuffer.PyBUF_STRIDES)
+        self.assertEqual(v.shape, (2, 3))
+        self.assertEqual(v.strides, (12, 4))
+
+    def test_fortran_contiguous(self):
+        # A multidimensional array is C contiguous, but not Fortran
+        # contiguous.  A one-dimensional array is contiguous in both orders.
+        ob = (c_int * 3 * 2)()
+        with self.assertRaises(BufferError):
+            _testbuffer.ndarray(ob, getbuf=_testbuffer.PyBUF_F_CONTIGUOUS)
+        _testbuffer.ndarray(ob, getbuf=_testbuffer.PyBUF_C_CONTIGUOUS)
+
+        ob = (c_int * 3)()
+        _testbuffer.ndarray(ob, getbuf=_testbuffer.PyBUF_F_CONTIGUOUS)
+        _testbuffer.ndarray(ob, getbuf=_testbuffer.PyBUF_C_CONTIGUOUS)
 
     def test_endian_types(self):
         for tp, fmt, shape, stride, itemtp in endian_types:

Modules/_ctypes/_ctypes_test.c

@@ -852,120 +852,11 @@ EXPORT(TestReg) get_last_tfrsuv_arg(void)
     return last_tfrsuv_arg;
 }
 
-PyObject *py_getBufferInfo(PyObject *self, PyObject *obj)
-{
-    int flags = PyBUF_FULL;
-    int ii;
-    Py_buffer view;
-    PyObject *v;
-    PyObject *x;
-    PyObject *d;
-    int buffer_err;
-
-    d = PyDict_New();
-    if (NULL == d) Py_RETURN_NONE;
-    buffer_err = PyObject_GetBuffer(obj, &view, flags);
-    v = PyLong_FromLong(buffer_err);
-    if (NULL != v){
-        PyDict_SetItemString(d, "err", v);
-        Py_DECREF(v);
-    }
-
-    if (0 == buffer_err) {
-        v = PyLong_FromSsize_t(view.len);
-        if (NULL != v){
-            PyDict_SetItemString(d, "len", v);
-            Py_DECREF(v);
-        }
-        v = PyBool_FromLong(view.readonly);
-        if (NULL != v){
-            PyDict_SetItemString(d, "readonly", v);
-            Py_DECREF(v);
-        }
-        v = PyLong_FromSsize_t(view.itemsize);
-        if (NULL != v){
-            PyDict_SetItemString(d, "itemsize", v);
-            Py_DECREF(v);
-        }
-        if(NULL == view.format) {
-            v = PyUnicode_FromString("");
-        } else {
-            v = PyUnicode_FromString(view.format);
-        }
-        if (NULL != v){
-            PyDict_SetItemString(d, "format", v);
-            Py_DECREF(v);
-        }
-        v = PyLong_FromLong(view.ndim);
-        if (NULL != v){
-            PyDict_SetItemString(d, "ndim", v);
-            Py_DECREF(v);
-        }
-        if (NULL == view.shape) {
-            PyDict_SetItemString(d, "shape", Py_None);
-        } else {
-            v = PyTuple_New(view.ndim);
-            if (NULL != v){
-                for (ii=0; ii<view.ndim; ++ii) {
-                    x = PyLong_FromSsize_t(view.shape[ii]);
-                    if (NULL == x) {
-                        Py_DECREF(v);
-                        Py_DECREF(d);
-                        return NULL;
-                    }
-                    PyTuple_SetItem(v, ii, x);
-                }
-                PyDict_SetItemString(d, "shape", v);
-                Py_DECREF(v);
-            }
-        }
-        if (NULL == view.strides) {
-            PyDict_SetItemString(d, "strides", Py_None);
-        } else {
-            v = PyTuple_New(view.ndim);
-            if (NULL != v){
-                for (ii=0; ii<view.ndim; ++ii) {
-                    x = PyLong_FromSsize_t(view.strides[ii]);
-                    if (NULL == x) {
-                        Py_DECREF(v);
-                        Py_DECREF(d);
-                        return NULL;
-                    }
-                    PyTuple_SetItem(v, ii, x);
-                }
-                PyDict_SetItemString(d, "strides", v);
-                Py_DECREF(v);
-            }
-        }
-        if (NULL == view.suboffsets) {
-            PyDict_SetItemString(d, "suboffsets", Py_None);
-        } else {
-            v = PyTuple_New(view.ndim);
-            if (NULL != v){
-                for (ii=0; ii<view.ndim; ++ii) {
-                    x = PyLong_FromSsize_t(view.suboffsets[ii]);
-                    if (NULL == x) {
-                        Py_DECREF(v);
-                        Py_DECREF(d);
-                        return NULL;
-                    }
-                    PyTuple_SetItem(v, ii, x);
-                }
-                PyDict_SetItemString(d, "suboffsets", v);
-                Py_DECREF(v);
-            }
-        }
-        PyBuffer_Release(&view);
-    }
-    return d;
-}
-
 static PyMethodDef module_methods[] = {
     {"get_last_tf_arg_s", get_last_tf_arg_s, METH_NOARGS},
     {"get_last_tf_arg_u", get_last_tf_arg_u, METH_NOARGS},
     {"func_si", py_func_si, METH_VARARGS},
     {"func", py_func, METH_NOARGS},
-    {"buffer_info", py_getBufferInfo, METH_O},
     {"get_generated_test_data", get_generated_test_data, METH_O},
     { NULL, NULL, 0, NULL},
 };