Merge pull request #2528 from mattip/numpy-base-access

WIP: MAINT: avoid numpy internals in {sg}et_array_base

CHANGES.rst

@@ -74,6 +74,8 @@ Other changes
   package size to about half of its previous size.  This makes the compiler
   slightly slower, by about 5-7%.
 
+* ``set_array_base`` now calls ``PyArray_SetBaseObject``. Also modified
+  ``get_array_base`` to remove direct access to NumPy internals.
 
 0.28.5 (2018-08-03)
 ===================

Cython/Includes/numpy/__init__.pxd

@@ -395,7 +395,7 @@ cdef extern from "numpy/arrayobject.h":
     npy_intp PyArray_DIM(ndarray, size_t)
     npy_intp PyArray_STRIDE(ndarray, size_t)
 
-    # object PyArray_BASE(ndarray) wrong refcount semantics
+    object PyArray_BASE(ndarray) #wrong refcount semantics?
     # dtype PyArray_DESCR(ndarray) wrong refcount semantics
     int PyArray_FLAGS(ndarray)
     npy_intp PyArray_ITEMSIZE(ndarray)
@@ -719,6 +719,7 @@ cdef extern from "numpy/arrayobject.h":
     object PyArray_CheckAxis (ndarray, int *, int)
     npy_intp PyArray_OverflowMultiplyList (npy_intp *, int)
     int PyArray_CompareString (char *, char *, size_t)
+    int PyArray_SetBaseObject(ndarray, object)
 
 
 # Typedefs that matches the runtime dtype objects in
@@ -973,23 +974,13 @@ cdef extern from "numpy/ufuncobject.h":
 
     int _import_umath() except -1
 
-
 cdef inline void set_array_base(ndarray arr, object base):
-     cdef PyObject* baseptr
-     if base is None:
-         baseptr = NULL
-     else:
     Py_INCREF(base) # important to do this before decref below!
-         baseptr = <PyObject*>base
-     Py_XDECREF(arr.base)
-     arr.base = baseptr
+    PyArray_SetBaseObject(arr, base)
 
 cdef inline object get_array_base(ndarray arr):
-    if arr.base is NULL:
-        return None
-    else:
-        return <object>arr.base
-
+    base = PyArray_BASE(arr)
+    return <object>base
 
 # Versions of the import_* functions which are more suitable for
 # Cython code.