cpython/Include/cpython/weakrefobject.h at 3.13 · python/cpython · GitHub

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#ifndef Py_CPYTHON_WEAKREFOBJECT_H

# error "this header file must not be included directly"

#endif

/* 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.

Py_hash_t 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;

vectorcallfunc vectorcall;

#ifdef Py_GIL_DISABLED

/* Pointer to the lock used when clearing in free-threaded builds.

* Normally this can be derived from wr_object, but in some cases we need

* to lock after wr_object has been set to Py_None.

PyMutex *weakrefs_lock;

#endif

};

PyAPI_FUNC(void) _PyWeakref_ClearRef(PyWeakReference *self);

Py_DEPRECATED(3.13) static inline PyObject* PyWeakref_GET_OBJECT(PyObject *ref_obj)

{

PyWeakReference *ref;

PyObject *obj;

assert(PyWeakref_Check(ref_obj));

ref = _Py_CAST(PyWeakReference*, ref_obj);

obj = ref->wr_object;

// 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.

if (Py_REFCNT(obj) > 0) {

return obj;

}

return Py_None;

}

#define PyWeakref_GET_OBJECT(ref) PyWeakref_GET_OBJECT(_PyObject_CAST(ref))

cpython/Include/cpython/weakrefobject.h at 3.13 · python/cpython · GitHub

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cpython/Include/cpython/weakrefobject.h at 3.13 · python/cpython · GitHub

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