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#include "Python.h"
#include "pycore_object.h" // _PyObject_GET_WEAKREFS_LISTPTR
#define GET_WEAKREFS_LISTPTR(o) \
((PyWeakReference **) _PyObject_GET_WEAKREFS_LISTPTR(o))
/*[clinic input]
module _weakref
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=ffec73b85846596d]*/
#include "clinic/_weakref.c.h"
/*[clinic input]
_weakref.getweakrefcount -> Py_ssize_t
object: object
/
Return the number of weak references to 'object'.
[clinic start generated code]*/
static Py_ssize_t
_weakref_getweakrefcount_impl(PyObject *module, PyObject *object)
/*[clinic end generated code: output=301806d59558ff3e input=cedb69711b6a2507]*/
{
PyWeakReference **list;
if (!PyType_SUPPORTS_WEAKREFS(Py_TYPE(object)))
return 0;
list = GET_WEAKREFS_LISTPTR(object);
return _PyWeakref_GetWeakrefCount(*list);
}
static int
is_dead_weakref(PyObject *value)
{
if (!PyWeakref_Check(value)) {
PyErr_SetString(PyExc_TypeError, "not a weakref");
return -1;
}
return PyWeakref_GET_OBJECT(value) == Py_None;
}
/*[clinic input]
_weakref._remove_dead_weakref -> object
dct: object(subclass_of='&PyDict_Type')
key: object
/
Atomically remove key from dict if it points to a dead weakref.
[clinic start generated code]*/
static PyObject *
_weakref__remove_dead_weakref_impl(PyObject *module, PyObject *dct,
PyObject *key)
/*[clinic end generated code: output=d9ff53061fcb875c input=19fc91f257f96a1d]*/
{
if (_PyDict_DelItemIf(dct, key, is_dead_weakref) < 0) {
if (PyErr_ExceptionMatches(PyExc_KeyError))
/* This function is meant to allow safe weak-value dicts
with GC in another thread (see issue #28427), so it's
ok if the key doesn't exist anymore.
*/
PyErr_Clear();
else
return NULL;
}
Py_RETURN_NONE;
}
PyDoc_STRVAR(weakref_getweakrefs__doc__,
"getweakrefs(object) -- return a list of all weak reference objects\n"
"that point to 'object'.");
static PyObject *
weakref_getweakrefs(PyObject *self, PyObject *object)
{
PyObject *result = NULL;
if (PyType_SUPPORTS_WEAKREFS(Py_TYPE(object))) {
PyWeakReference **list = GET_WEAKREFS_LISTPTR(object);
Py_ssize_t count = _PyWeakref_GetWeakrefCount(*list);
result = PyList_New(count);
if (result != NULL) {
PyWeakReference *current = *list;
Py_ssize_t i;
for (i = 0; i < count; ++i) {
PyList_SET_ITEM(result, i, (PyObject *) current);
Py_INCREF(current);
current = current->wr_next;
}
}
}
else {
result = PyList_New(0);
}
return result;
}
PyDoc_STRVAR(weakref_proxy__doc__,
"proxy(object[, callback]) -- create a proxy object that weakly\n"
"references 'object'. 'callback', if given, is called with a\n"
"reference to the proxy when 'object' is about to be finalized.");
static PyObject *
weakref_proxy(PyObject *self, PyObject *args)
{
PyObject *object;
PyObject *callback = NULL;
PyObject *result = NULL;
if (PyArg_UnpackTuple(args, "proxy", 1, 2, &object, &callback)) {
result = PyWeakref_NewProxy(object, callback);
}
return result;
}
static PyMethodDef
weakref_functions[] = {
_WEAKREF_GETWEAKREFCOUNT_METHODDEF
_WEAKREF__REMOVE_DEAD_WEAKREF_METHODDEF
{"getweakrefs", weakref_getweakrefs, METH_O,
weakref_getweakrefs__doc__},
{"proxy", weakref_proxy, METH_VARARGS,
weakref_proxy__doc__},
{NULL, NULL, 0, NULL}
};
static int
weakref_exec(PyObject *module)
{
Py_INCREF(&_PyWeakref_RefType);
if (PyModule_AddObject(module, "ref", (PyObject *) &_PyWeakref_RefType) < 0) {
Py_DECREF(&_PyWeakref_RefType);
return -1;
}
Py_INCREF(&_PyWeakref_RefType);
if (PyModule_AddObject(module, "ReferenceType",
(PyObject *) &_PyWeakref_RefType) < 0) {
Py_DECREF(&_PyWeakref_RefType);
return -1;
}
Py_INCREF(&_PyWeakref_ProxyType);
if (PyModule_AddObject(module, "ProxyType",
(PyObject *) &_PyWeakref_ProxyType) < 0) {
Py_DECREF(&_PyWeakref_ProxyType);
return -1;
}
Py_INCREF(&_PyWeakref_CallableProxyType);
if (PyModule_AddObject(module, "CallableProxyType",
(PyObject *) &_PyWeakref_CallableProxyType) < 0) {
Py_DECREF(&_PyWeakref_CallableProxyType);
return -1;
}
return 0;
}
static struct PyModuleDef_Slot weakref_slots[] = {
{Py_mod_exec, weakref_exec},
{0, NULL}
};
static struct PyModuleDef weakrefmodule = {
PyModuleDef_HEAD_INIT,
"_weakref",
"Weak-reference support module.",
0,
weakref_functions,
weakref_slots,
NULL,
NULL,
NULL
};
PyMODINIT_FUNC
PyInit__weakref(void)
{
return PyModuleDef_Init(&weakrefmodule);
}
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