/src/cpython-install/include/python3.15/cpython/weakrefobject.h
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1 | | #ifndef Py_CPYTHON_WEAKREFOBJECT_H |
2 | | # error "this header file must not be included directly" |
3 | | #endif |
4 | | |
5 | | /* PyWeakReference is the base struct for the Python ReferenceType, ProxyType, |
6 | | * and CallableProxyType. |
7 | | */ |
8 | | struct _PyWeakReference { |
9 | | PyObject_HEAD |
10 | | |
11 | | /* The object to which this is a weak reference, or Py_None if none. |
12 | | * Note that this is a stealth reference: wr_object's refcount is |
13 | | * not incremented to reflect this pointer. |
14 | | */ |
15 | | PyObject *wr_object; |
16 | | |
17 | | /* A callable to invoke when wr_object dies, or NULL if none. */ |
18 | | PyObject *wr_callback; |
19 | | |
20 | | /* A cache for wr_object's hash code. As usual for hashes, this is -1 |
21 | | * if the hash code isn't known yet. |
22 | | */ |
23 | | Py_hash_t hash; |
24 | | |
25 | | /* If wr_object is weakly referenced, wr_object has a doubly-linked NULL- |
26 | | * terminated list of weak references to it. These are the list pointers. |
27 | | * If wr_object goes away, wr_object is set to Py_None, and these pointers |
28 | | * have no meaning then. |
29 | | */ |
30 | | PyWeakReference *wr_prev; |
31 | | PyWeakReference *wr_next; |
32 | | vectorcallfunc vectorcall; |
33 | | |
34 | | #ifdef Py_GIL_DISABLED |
35 | | /* Pointer to the lock used when clearing in free-threaded builds. |
36 | | * Normally this can be derived from wr_object, but in some cases we need |
37 | | * to lock after wr_object has been set to Py_None. |
38 | | */ |
39 | | PyMutex *weakrefs_lock; |
40 | | #endif |
41 | | }; |
42 | | |
43 | | PyAPI_FUNC(void) _PyWeakref_ClearRef(PyWeakReference *self); |
44 | | |
45 | | #define _PyWeakref_CAST(op) \ |
46 | | (assert(PyWeakref_Check(op)), _Py_CAST(PyWeakReference*, (op))) |
47 | | |
48 | | // Test if a weak reference is dead. |
49 | | PyAPI_FUNC(int) PyWeakref_IsDead(PyObject *ref); |
50 | | |
51 | | Py_DEPRECATED(3.13) static inline PyObject* PyWeakref_GET_OBJECT(PyObject *ref_obj) |
52 | 0 | { |
53 | 0 | PyWeakReference *ref = _PyWeakref_CAST(ref_obj); |
54 | 0 | PyObject *obj = ref->wr_object; |
55 | 0 | // Explanation for the Py_REFCNT() check: when a weakref's target is part |
56 | 0 | // of a long chain of deallocations which triggers the trashcan mechanism, |
57 | 0 | // clearing the weakrefs can be delayed long after the target's refcount |
58 | 0 | // has dropped to zero. In the meantime, code accessing the weakref will |
59 | 0 | // be able to "see" the target object even though it is supposed to be |
60 | 0 | // unreachable. See issue gh-60806. |
61 | 0 | if (Py_REFCNT(obj) > 0) { |
62 | 0 | return obj; |
63 | 0 | } |
64 | 0 | return Py_None; |
65 | 0 | } |
66 | | #define PyWeakref_GET_OBJECT(ref) PyWeakref_GET_OBJECT(_PyObject_CAST(ref)) |