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bpo-40077: Convert mmap.mmap static type to a heap type (GH-23108)
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Erlend Egeberg Aasland authored Nov 3, 2020
1 parent 9568622 commit 74b4eda
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Showing 2 changed files with 91 additions and 68 deletions.
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core and Builtins/2020-11-02-14-39-48.bpo-40077.grY9TG.rst
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@@ -0,0 +1 @@
Convert :mod:`mmap` to use heap types.
158 changes: 90 additions & 68 deletions Modules/mmapmodule.c
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Expand Up @@ -20,6 +20,7 @@

#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include "structmember.h" // PyMemberDef
#include <stddef.h> // offsetof()

#ifndef MS_WINDOWS
Expand Down Expand Up @@ -113,10 +114,23 @@ typedef struct {
access_mode access;
} mmap_object;

typedef struct {
PyTypeObject *mmap_object_type;
} mmap_state;

static mmap_state *
get_mmap_state(PyObject *module)
{
mmap_state *state = PyModule_GetState(module);
assert(state);
return state;
}

static void
mmap_object_dealloc(mmap_object *m_obj)
{
PyTypeObject *tp = Py_TYPE(m_obj);

#ifdef MS_WINDOWS
Py_BEGIN_ALLOW_THREADS
if (m_obj->data != NULL)
Expand All @@ -142,7 +156,9 @@ mmap_object_dealloc(mmap_object *m_obj)

if (m_obj->weakreflist != NULL)
PyObject_ClearWeakRefs((PyObject *) m_obj);
Py_TYPE(m_obj)->tp_free((PyObject*)m_obj);

tp->tp_free(m_obj);
Py_DECREF(tp);
}

static PyObject *
Expand Down Expand Up @@ -793,6 +809,11 @@ mmap_madvise_method(mmap_object *self, PyObject *args)
}
#endif // HAVE_MADVISE

static struct PyMemberDef mmap_object_members[] = {
{"__weaklistoffset__", T_PYSSIZET, offsetof(mmap_object, weakreflist), READONLY},
{NULL},
};

static struct PyMethodDef mmap_object_methods[] = {
{"close", (PyCFunction) mmap_close_method, METH_NOARGS},
{"find", (PyCFunction) mmap_find_method, METH_VARARGS},
Expand Down Expand Up @@ -1035,27 +1056,6 @@ mmap_ass_subscript(mmap_object *self, PyObject *item, PyObject *value)
}
}

static PySequenceMethods mmap_as_sequence = {
(lenfunc)mmap_length, /*sq_length*/
0, /*sq_concat*/
0, /*sq_repeat*/
(ssizeargfunc)mmap_item, /*sq_item*/
0, /*sq_slice*/
(ssizeobjargproc)mmap_ass_item, /*sq_ass_item*/
0, /*sq_ass_slice*/
};

static PyMappingMethods mmap_as_mapping = {
(lenfunc)mmap_length,
(binaryfunc)mmap_subscript,
(objobjargproc)mmap_ass_subscript,
};

static PyBufferProcs mmap_as_buffer = {
(getbufferproc)mmap_buffer_getbuf,
(releasebufferproc)mmap_buffer_releasebuf,
};

static PyObject *
new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict);

Expand Down Expand Up @@ -1083,47 +1083,39 @@ The default value is MAP_SHARED.\n\
To map anonymous memory, pass -1 as the fileno (both versions).");


static PyTypeObject mmap_object_type = {
PyVarObject_HEAD_INIT(NULL, 0)
"mmap.mmap", /* tp_name */
sizeof(mmap_object), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)mmap_object_dealloc, /* tp_dealloc */
0, /* tp_vectorcall_offset */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_as_async */
(reprfunc)mmap__repr__method, /* tp_repr */
0, /* tp_as_number */
&mmap_as_sequence, /* tp_as_sequence */
&mmap_as_mapping, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
&mmap_as_buffer, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
mmap_doc, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
offsetof(mmap_object, weakreflist), /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
mmap_object_methods, /* tp_methods */
0, /* tp_members */
mmap_object_getset, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
new_mmap_object, /* tp_new */
PyObject_Del, /* tp_free */
static PyType_Slot mmap_object_slots[] = {
{Py_tp_new, new_mmap_object},
{Py_tp_alloc, PyType_GenericAlloc},
{Py_tp_dealloc, mmap_object_dealloc},
{Py_tp_free, PyObject_Del},
{Py_tp_repr, mmap__repr__method},
{Py_tp_doc, (void *)mmap_doc},
{Py_tp_methods, mmap_object_methods},
{Py_tp_members, mmap_object_members},
{Py_tp_getset, mmap_object_getset},
{Py_tp_getattro, PyObject_GenericGetAttr},

/* as sequence */
{Py_sq_length, mmap_length},
{Py_sq_item, mmap_item},
{Py_sq_ass_item, mmap_ass_item},

/* as mapping */
{Py_mp_length, mmap_length},
{Py_mp_subscript, mmap_subscript},
{Py_mp_ass_subscript, mmap_ass_subscript},

/* as buffer */
{Py_bf_getbuffer, mmap_buffer_getbuf},
{Py_bf_releasebuffer, mmap_buffer_releasebuf},
{0, NULL},
};

static PyType_Spec mmap_object_spec = {
.name = "mmap.mmap",
.basicsize = sizeof(mmap_object),
.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
.slots = mmap_object_slots,
};


Expand Down Expand Up @@ -1509,19 +1501,46 @@ new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict)
}
#endif /* MS_WINDOWS */

static int
mmap_traverse(PyObject *module, visitproc visit, void *arg)
{
mmap_state *state = get_mmap_state(module);
Py_VISIT(state->mmap_object_type);
return 0;
}

static int
mmap_clear(PyObject *module)
{
mmap_state *state = get_mmap_state(module);
Py_CLEAR(state->mmap_object_type);
return 0;
}

static void
mmap_free(void *module)
{
mmap_clear((PyObject *)module);
}

static int
mmap_exec(PyObject *module)
{
if (PyType_Ready(&mmap_object_type) < 0) {
return -1;
}
mmap_state *state = get_mmap_state(module);

Py_INCREF(PyExc_OSError);
if (PyModule_AddObject(module, "error", PyExc_OSError) < 0) {
Py_DECREF(PyExc_OSError);
return -1;
}
if (PyModule_AddType(module, &mmap_object_type) < 0) {

state->mmap_object_type = (PyTypeObject *)PyType_FromModuleAndSpec(module,
&mmap_object_spec,
NULL);
if (state->mmap_object_type == NULL) {
return -1;
}
if (PyModule_AddType(module, state->mmap_object_type) < 0) {
return -1;
}

Expand Down Expand Up @@ -1660,8 +1679,11 @@ static PyModuleDef_Slot mmap_slots[] = {
static struct PyModuleDef mmapmodule = {
PyModuleDef_HEAD_INIT,
.m_name = "mmap",
.m_size = 0,
.m_size = sizeof(mmap_state),
.m_slots = mmap_slots,
.m_traverse = mmap_traverse,
.m_clear = mmap_clear,
.m_free = mmap_free,
};

PyMODINIT_FUNC
Expand Down

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