diff options
Diffstat (limited to 'numpy/core/_internal.py')
| -rw-r--r-- | numpy/core/_internal.py | 57 |
1 files changed, 11 insertions, 46 deletions
diff --git a/numpy/core/_internal.py b/numpy/core/_internal.py index b0ea603e1..05e401e0b 100644 --- a/numpy/core/_internal.py +++ b/numpy/core/_internal.py @@ -247,55 +247,13 @@ class _missing_ctypes(object): self.value = ptr -class _unsafe_first_element_pointer(object): - """ - Helper to allow viewing an array as a ctypes pointer to the first element - - This avoids: - * dealing with strides - * `.view` rejecting object-containing arrays - * `memoryview` not supporting overlapping fields - """ - def __init__(self, arr): - self.base = arr - - @property - def __array_interface__(self): - i = dict( - shape=(), - typestr='|V0', - data=(self.base.__array_interface__['data'][0], False), - strides=(), - version=3, - ) - return i - - -def _get_void_ptr(arr): - """ - Get a `ctypes.c_void_p` to arr.data, that keeps a reference to the array - """ - import numpy as np - # convert to a 0d array that has a data pointer referrign to the start - # of arr. This holds a reference to arr. - simple_arr = np.asarray(_unsafe_first_element_pointer(arr)) - - # create a `char[0]` using the same memory. - c_arr = (ctypes.c_char * 0).from_buffer(simple_arr) - - # finally cast to void* - return ctypes.cast(ctypes.pointer(c_arr), ctypes.c_void_p) - - class _ctypes(object): def __init__(self, array, ptr=None): self._arr = array if ctypes: self._ctypes = ctypes - # get a void pointer to the buffer, which keeps the array alive - self._data = _get_void_ptr(array) - assert self._data.value == ptr + self._data = self._ctypes.c_void_p(ptr) else: # fake a pointer-like object that holds onto the reference self._ctypes = _missing_ctypes() @@ -317,7 +275,14 @@ class _ctypes(object): The returned pointer will keep a reference to the array. """ - return self._ctypes.cast(self._data, obj) + # _ctypes.cast function causes a circular reference of self._data in + # self._data._objects. Attributes of self._data cannot be released + # until gc.collect is called. Make a copy of the pointer first then let + # it hold the array reference. This is a workaround to circumvent the + # CPython bug https://bugs.python.org/issue12836 + ptr = self._ctypes.cast(self._data, obj) + ptr._arr = self._arr + return ptr def shape_as(self, obj): """ @@ -348,7 +313,7 @@ class _ctypes(object): crashing. User Beware! The value of this attribute is exactly the same as ``self._array_interface_['data'][0]``. - Note that unlike `data_as`, a reference will not be kept to the array: + Note that unlike ``data_as``, a reference will not be kept to the array: code like ``ctypes.c_void_p((a + b).ctypes.data)`` will result in a pointer to a deallocated array, and should be spelt ``(a + b).ctypes.data_as(ctypes.c_void_p)`` @@ -385,7 +350,7 @@ class _ctypes(object): Enables `c_func(some_array.ctypes)` """ - return self._data + return self.data_as(ctypes.c_void_p) # kept for compatibility get_data = data.fget |