blob: 51b2bb6b11ede96422000aae34da045c636329e0 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
#ifndef Py_INTERNAL_WEAKREF_H
#define Py_INTERNAL_WEAKREF_H
#ifdef __cplusplus
extern "C" {
#endif
#ifndef Py_BUILD_CORE
# error "this header requires Py_BUILD_CORE define"
#endif
static inline PyObject* _PyWeakref_GET_REF(PyObject *ref_obj) {
assert(PyWeakref_Check(ref_obj));
PyWeakReference *ref = _Py_CAST(PyWeakReference*, ref_obj);
PyObject *obj = ref->wr_object;
if (obj == Py_None) {
// clear_weakref() was called
return NULL;
}
// Explanation for the Py_REFCNT() check: when a weakref's target is part
// of a long chain of deallocations which triggers the trashcan mechanism,
// clearing the weakrefs can be delayed long after the target's refcount
// has dropped to zero. In the meantime, code accessing the weakref will
// be able to "see" the target object even though it is supposed to be
// unreachable. See issue gh-60806.
Py_ssize_t refcnt = Py_REFCNT(obj);
if (refcnt == 0) {
return NULL;
}
assert(refcnt > 0);
return Py_NewRef(obj);
}
static inline int _PyWeakref_IS_DEAD(PyObject *ref_obj) {
assert(PyWeakref_Check(ref_obj));
PyWeakReference *ref = _Py_CAST(PyWeakReference*, ref_obj);
PyObject *obj = ref->wr_object;
if (obj == Py_None) {
// clear_weakref() was called
return 1;
}
// See _PyWeakref_GET_REF() for the rationale of this test
return (Py_REFCNT(obj) == 0);
}
extern Py_ssize_t _PyWeakref_GetWeakrefCount(PyWeakReference *head);
extern void _PyWeakref_ClearRef(PyWeakReference *self);
#ifdef __cplusplus
}
#endif
#endif /* !Py_INTERNAL_WEAKREF_H */
|
