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cpython/Include/weakrefobject.h
Fred Drake 0a4dd390bf Make weak references subclassable:
- weakref.ref and weakref.ReferenceType will become aliases for each
  other

- weakref.ref will be a modern, new-style class with proper __new__
  and __init__ methods

- weakref.WeakValueDictionary will have a lighter memory footprint,
  using a new weakref.ref subclass to associate the key with the
  value, allowing us to have only a single object of overhead for each
  dictionary entry (currently, there are 3 objects of overhead per
  entry: a weakref to the value, a weakref to the dictionary, and a
  function object used as a weakref callback; the weakref to the
  dictionary could be avoided without this change)

- a new macro, PyWeakref_CheckRefExact(), will be added

- PyWeakref_CheckRef() will check for subclasses of weakref.ref

This closes SF patch #983019.
2004-07-02 18:57:45 +00:00

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1.6 KiB
C

/* Weak references objects for Python. */
#ifndef Py_WEAKREFOBJECT_H
#define Py_WEAKREFOBJECT_H
#ifdef __cplusplus
extern "C" {
#endif
typedef struct _PyWeakReference PyWeakReference;
struct _PyWeakReference {
PyObject_HEAD
PyObject *wr_object;
PyObject *wr_callback;
long hash;
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) \
((op)->ob_type == &_PyWeakref_RefType)
#define PyWeakref_CheckProxy(op) \
(((op)->ob_type == &_PyWeakref_ProxyType) || \
((op)->ob_type == &_PyWeakref_CallableProxyType))
/* This macro calls PyWeakref_CheckRef() last since that can involve a
function call; this makes it more likely that the function call
will be avoided. */
#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(long) _PyWeakref_GetWeakrefCount(PyWeakReference *head);
PyAPI_FUNC(void) _PyWeakref_ClearRef(PyWeakReference *self);
#define PyWeakref_GET_OBJECT(ref) (((PyWeakReference *)(ref))->wr_object)
#ifdef __cplusplus
}
#endif
#endif /* !Py_WEAKREFOBJECT_H */