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_weakref.c
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194 lines (161 loc) · 5.01 KB
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#include "Python.h"
#include "pycore_dict.h" // _PyDict_DelItemIf()
#include "pycore_object.h" // _PyObject_GET_WEAKREFS_LISTPTR()
#include "pycore_weakref.h" // _PyWeakref_IS_DEAD()
#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=7d4d04fcaccf64d5]*/
{
return _PyWeakref_GetWeakrefCount(object);
}
static int
is_dead_weakref(PyObject *value)
{
if (!PyWeakref_Check(value)) {
PyErr_SetString(PyExc_TypeError, "not a weakref");
return -1;
}
return _PyWeakref_IS_DEAD(value);
}
/*[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;
}
/*[clinic input]
_weakref.getweakrefs
object: object
/
Return a list of all weak reference objects pointing to 'object'.
[clinic start generated code]*/
static PyObject *
_weakref_getweakrefs(PyObject *module, PyObject *object)
/*[clinic end generated code: output=25c7731d8e011824 input=00c6d0e5d3206693]*/
{
if (!_PyType_SUPPORTS_WEAKREFS(Py_TYPE(object))) {
return PyList_New(0);
}
PyObject *result = PyList_New(0);
if (result == NULL) {
return NULL;
}
LOCK_WEAKREFS(object);
PyWeakReference *current = *GET_WEAKREFS_LISTPTR(object);
while (current != NULL) {
PyObject *curobj = (PyObject *) current;
if (_Py_TryIncref(curobj)) {
if (PyList_Append(result, curobj)) {
UNLOCK_WEAKREFS(object);
Py_DECREF(curobj);
Py_DECREF(result);
return NULL;
}
else {
// Undo our _Py_TryIncref. This is safe to do with the lock
// held in free-threaded builds; the list holds a reference to
// curobj so we're guaranteed not to invoke the destructor.
Py_DECREF(curobj);
}
}
current = current->wr_next;
}
UNLOCK_WEAKREFS(object);
return result;
}
/*[clinic input]
_weakref.proxy
object: object
callback: object(c_default="NULL") = None
/
Create a proxy object that weakly references 'object'.
'callback', if given, is called with a reference to the
proxy when 'object' is about to be finalized.
[clinic start generated code]*/
static PyObject *
_weakref_proxy_impl(PyObject *module, PyObject *object, PyObject *callback)
/*[clinic end generated code: output=d68fa4ad9ea40519 input=4808adf22fd137e7]*/
{
return PyWeakref_NewProxy(object, callback);
}
static PyMethodDef
weakref_functions[] = {
_WEAKREF_GETWEAKREFCOUNT_METHODDEF
_WEAKREF__REMOVE_DEAD_WEAKREF_METHODDEF
_WEAKREF_GETWEAKREFS_METHODDEF
_WEAKREF_PROXY_METHODDEF
{NULL, NULL, 0, NULL}
};
static int
weakref_exec(PyObject *module)
{
if (PyModule_AddObjectRef(module, "ref", (PyObject *) &_PyWeakref_RefType) < 0) {
return -1;
}
if (PyModule_AddObjectRef(module, "ReferenceType",
(PyObject *) &_PyWeakref_RefType) < 0) {
return -1;
}
if (PyModule_AddObjectRef(module, "ProxyType",
(PyObject *) &_PyWeakref_ProxyType) < 0) {
return -1;
}
if (PyModule_AddObjectRef(module, "CallableProxyType",
(PyObject *) &_PyWeakref_CallableProxyType) < 0) {
return -1;
}
return 0;
}
static struct PyModuleDef_Slot weakref_slots[] = {
{Py_mod_exec, weakref_exec},
{Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
{Py_mod_gil, Py_MOD_GIL_NOT_USED},
{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);
}