| /* Weak references objects for Python. */ |
| |
| #ifndef Py_WEAKREFOBJECT_H |
| #define Py_WEAKREFOBJECT_H |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| |
| typedef struct _PyWeakReference PyWeakReference; |
| |
| /* PyWeakReference is the base struct for the Python ReferenceType, ProxyType, |
| * and CallableProxyType. |
| */ |
| struct _PyWeakReference { |
| PyObject_HEAD |
| |
| /* The object to which this is a weak reference, or Py_None if none. |
| * Note that this is a stealth reference: wr_object's refcount is |
| * not incremented to reflect this pointer. |
| */ |
| PyObject *wr_object; |
| |
| /* A callable to invoke when wr_object dies, or NULL if none. */ |
| PyObject *wr_callback; |
| |
| /* A cache for wr_object's hash code. As usual for hashes, this is -1 |
| * if the hash code isn't known yet. |
| */ |
| long hash; |
| |
| /* If wr_object is weakly referenced, wr_object has a doubly-linked NULL- |
| * terminated list of weak references to it. These are the list pointers. |
| * If wr_object goes away, wr_object is set to Py_None, and these pointers |
| * have no meaning then. |
| */ |
| PyWeakReference *wr_prev; |
| PyWeakReference *wr_next; |
| }; |
| |
| PyAPI_DATA(PyTypeObject) _PyWeakref_RefType; |
| PyAPI_DATA(PyTypeObject) _PyWeakref_ProxyType; |
| PyAPI_DATA(PyTypeObject) _PyWeakref_CallableProxyType; |
| |
| #define PyWeakref_CheckRef(op) PyObject_TypeCheck(op, &_PyWeakref_RefType) |
| #define PyWeakref_CheckRefExact(op) \ |
| (Py_TYPE(op) == &_PyWeakref_RefType) |
| #define PyWeakref_CheckProxy(op) \ |
| ((Py_TYPE(op) == &_PyWeakref_ProxyType) || \ |
| (Py_TYPE(op) == &_PyWeakref_CallableProxyType)) |
| |
| #define PyWeakref_Check(op) \ |
| (PyWeakref_CheckRef(op) || PyWeakref_CheckProxy(op)) |
| |
| |
| PyAPI_FUNC(PyObject *) PyWeakref_NewRef(PyObject *ob, |
| PyObject *callback); |
| PyAPI_FUNC(PyObject *) PyWeakref_NewProxy(PyObject *ob, |
| PyObject *callback); |
| PyAPI_FUNC(PyObject *) PyWeakref_GetObject(PyObject *ref); |
| |
| PyAPI_FUNC(Py_ssize_t) _PyWeakref_GetWeakrefCount(PyWeakReference *head); |
| |
| PyAPI_FUNC(void) _PyWeakref_ClearRef(PyWeakReference *self); |
| |
| /* 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 #16602. */ |
| |
| #define PyWeakref_GET_OBJECT(ref) \ |
| (Py_REFCNT(((PyWeakReference *)(ref))->wr_object) > 0 \ |
| ? ((PyWeakReference *)(ref))->wr_object \ |
| : Py_None) |
| |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| #endif /* !Py_WEAKREFOBJECT_H */ |