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/* PickleBuffer object implementation */
#include "Python.h"
#include <stddef.h>
typedef struct {
PyObject_HEAD
/* The view exported by the original object */
Py_buffer view;
PyObject *weakreflist;
} PyPickleBufferObject;
/* C API */
PyObject *
PyPickleBuffer_FromObject(PyObject *base)
{
PyTypeObject *type = &PyPickleBuffer_Type;
PyPickleBufferObject *self;
self = (PyPickleBufferObject *) type->tp_alloc(type, 0);
if (self == NULL) {
return NULL;
}
self->view.obj = NULL;
self->weakreflist = NULL;
if (PyObject_GetBuffer(base, &self->view, PyBUF_FULL_RO) < 0) {
Py_DECREF(self);
return NULL;
}
return (PyObject *) self;
}
const Py_buffer *
PyPickleBuffer_GetBuffer(PyObject *obj)
{
PyPickleBufferObject *self = (PyPickleBufferObject *) obj;
if (!PyPickleBuffer_Check(obj)) {
PyErr_Format(PyExc_TypeError,
"expected PickleBuffer, %.200s found",
Py_TYPE(obj)->tp_name);
return NULL;
}
if (self->view.obj == NULL) {
PyErr_SetString(PyExc_ValueError,
"operation forbidden on released PickleBuffer object");
return NULL;
}
return &self->view;
}
int
PyPickleBuffer_Release(PyObject *obj)
{
PyPickleBufferObject *self = (PyPickleBufferObject *) obj;
if (!PyPickleBuffer_Check(obj)) {
PyErr_Format(PyExc_TypeError,
"expected PickleBuffer, %.200s found",
Py_TYPE(obj)->tp_name);
return -1;
}
PyBuffer_Release(&self->view);
return 0;
}
static PyObject *
picklebuf_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
PyPickleBufferObject *self;
PyObject *base;
char *keywords[] = {"", NULL};
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:PickleBuffer",
keywords, &base)) {
return NULL;
}
self = (PyPickleBufferObject *) type->tp_alloc(type, 0);
if (self == NULL) {
return NULL;
}
self->view.obj = NULL;
self->weakreflist = NULL;
if (PyObject_GetBuffer(base, &self->view, PyBUF_FULL_RO) < 0) {
Py_DECREF(self);
return NULL;
}
return (PyObject *) self;
}
static int
picklebuf_traverse(PyPickleBufferObject *self, visitproc visit, void *arg)
{
Py_VISIT(self->view.obj);
return 0;
}
static int
picklebuf_clear(PyPickleBufferObject *self)
{
PyBuffer_Release(&self->view);
return 0;
}
static void
picklebuf_dealloc(PyPickleBufferObject *self)
{
PyObject_GC_UnTrack(self);
if (self->weakreflist != NULL)
PyObject_ClearWeakRefs((PyObject *) self);
PyBuffer_Release(&self->view);
Py_TYPE(self)->tp_free((PyObject *) self);
}
/* Buffer API */
static int
picklebuf_getbuf(PyPickleBufferObject *self, Py_buffer *view, int flags)
{
if (self->view.obj == NULL) {
PyErr_SetString(PyExc_ValueError,
"operation forbidden on released PickleBuffer object");
return -1;
}
return PyObject_GetBuffer(self->view.obj, view, flags);
}
static void
picklebuf_releasebuf(PyPickleBufferObject *self, Py_buffer *view)
{
/* Since our bf_getbuffer redirects to the original object, this
* implementation is never called. It only exists to signal that
* buffers exported by PickleBuffer have non-trivial releasing
* behaviour (see check in Python/getargs.c).
*/
}
static PyBufferProcs picklebuf_as_buffer = {
.bf_getbuffer = (getbufferproc) picklebuf_getbuf,
.bf_releasebuffer = (releasebufferproc) picklebuf_releasebuf,
};
/* Methods */
static PyObject *
picklebuf_raw(PyPickleBufferObject *self, PyObject *Py_UNUSED(ignored))
{
if (self->view.obj == NULL) {
PyErr_SetString(PyExc_ValueError,
"operation forbidden on released PickleBuffer object");
return NULL;
}
if (self->view.suboffsets != NULL
|| !PyBuffer_IsContiguous(&self->view, 'A')) {
PyErr_SetString(PyExc_BufferError,
"cannot extract raw buffer from non-contiguous buffer");
return NULL;
}
PyObject *m = PyMemoryView_FromObject((PyObject *) self);
if (m == NULL) {
return NULL;
}
PyMemoryViewObject *mv = (PyMemoryViewObject *) m;
assert(mv->view.suboffsets == NULL);
/* Mutate memoryview instance to make it a "raw" memoryview */
mv->view.format = "B";
mv->view.ndim = 1;
mv->view.itemsize = 1;
/* shape = (length,) */
mv->view.shape = &mv->view.len;
/* strides = (1,) */
mv->view.strides = &mv->view.itemsize;
/* Fix memoryview state flags */
/* XXX Expose memoryobject.c's init_flags() instead? */
mv->flags = _Py_MEMORYVIEW_C | _Py_MEMORYVIEW_FORTRAN;
return m;
}
PyDoc_STRVAR(picklebuf_raw_doc,
"raw($self, /)\n--\n\
\n\
Return a memoryview of the raw memory underlying this buffer.\n\
Will raise BufferError is the buffer isn't contiguous.");
static PyObject *
picklebuf_release(PyPickleBufferObject *self, PyObject *Py_UNUSED(ignored))
{
PyBuffer_Release(&self->view);
Py_RETURN_NONE;
}
PyDoc_STRVAR(picklebuf_release_doc,
"release($self, /)\n--\n\
\n\
Release the underlying buffer exposed by the PickleBuffer object.");
static PyMethodDef picklebuf_methods[] = {
{"raw", (PyCFunction) picklebuf_raw, METH_NOARGS, picklebuf_raw_doc},
{"release", (PyCFunction) picklebuf_release, METH_NOARGS, picklebuf_release_doc},
{NULL, NULL}
};
PyTypeObject PyPickleBuffer_Type = {
PyVarObject_HEAD_INIT(NULL, 0)
.tp_name = "pickle.PickleBuffer",
.tp_doc = PyDoc_STR("Wrapper for potentially out-of-band buffers"),
.tp_basicsize = sizeof(PyPickleBufferObject),
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
.tp_new = picklebuf_new,
.tp_dealloc = (destructor) picklebuf_dealloc,
.tp_traverse = (traverseproc) picklebuf_traverse,
.tp_clear = (inquiry) picklebuf_clear,
.tp_weaklistoffset = offsetof(PyPickleBufferObject, weakreflist),
.tp_as_buffer = &picklebuf_as_buffer,
.tp_methods = picklebuf_methods,
};
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