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#include "Python.h"
#define GET_WEAKREFS_LISTPTR(o) \
((PyWeakReference **) PyObject_GET_WEAKREFS_LISTPTR(o))
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;
}
PyDoc_STRVAR(remove_dead_weakref__doc__,
"_remove_dead_weakref(dict, key) -- atomically remove key from dict\n"
"if it points to a dead weakref.");
static PyObject *
remove_dead_weakref(PyObject *self, PyObject *args)
{
PyObject *dct, *key;
if (!PyArg_ParseTuple(args, "O!O:_remove_dead_weakref",
&PyDict_Type, &dct, &key)) {
return NULL;
}
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_getweakrefcount__doc__,
"getweakrefcount(object) -- return the number of weak references\n"
"to 'object'.");
static PyObject *
weakref_getweakrefcount(PyObject *self, PyObject *object)
{
PyObject *result = NULL;
if (PyType_SUPPORTS_WEAKREFS(Py_TYPE(object))) {
PyWeakReference **list = GET_WEAKREFS_LISTPTR(object);
result = PyInt_FromSsize_t(_PyWeakref_GetWeakrefCount(*list));
}
else
result = PyInt_FromLong(0);
return result;
}
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[] = {
{"getweakrefcount", weakref_getweakrefcount, METH_O,
weakref_getweakrefcount__doc__},
{"getweakrefs", weakref_getweakrefs, METH_O,
weakref_getweakrefs__doc__},
{"proxy", weakref_proxy, METH_VARARGS,
weakref_proxy__doc__},
{"_remove_dead_weakref", remove_dead_weakref, METH_VARARGS,
remove_dead_weakref__doc__},
{NULL, NULL, 0, NULL}
};
PyMODINIT_FUNC
init_weakref(void)
{
PyObject *m;
m = Py_InitModule3("_weakref", weakref_functions,
"Weak-reference support module.");
if (m != NULL) {
Py_INCREF(&_PyWeakref_RefType);
PyModule_AddObject(m, "ref",
(PyObject *) &_PyWeakref_RefType);
Py_INCREF(&_PyWeakref_RefType);
PyModule_AddObject(m, "ReferenceType",
(PyObject *) &_PyWeakref_RefType);
Py_INCREF(&_PyWeakref_ProxyType);
PyModule_AddObject(m, "ProxyType",
(PyObject *) &_PyWeakref_ProxyType);
Py_INCREF(&_PyWeakref_CallableProxyType);
PyModule_AddObject(m, "CallableProxyType",
(PyObject *) &_PyWeakref_CallableProxyType);
}
}
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