/Modules/_weakref.c

  1#include "Python.h"
  2
  3
  4#define GET_WEAKREFS_LISTPTR(o) \
  5        ((PyWeakReference **) PyObject_GET_WEAKREFS_LISTPTR(o))
  6
  7
  8PyDoc_STRVAR(weakref_getweakrefcount__doc__,
  9"getweakrefcount(object) -- return the number of weak references\n"
 10"to 'object'.");
 11
 12static PyObject *
 13weakref_getweakrefcount(PyObject *self, PyObject *object)
 14{
 15    PyObject *result = NULL;
 16
 17    if (PyType_SUPPORTS_WEAKREFS(Py_TYPE(object))) {
 18        PyWeakReference **list = GET_WEAKREFS_LISTPTR(object);
 19
 20        result = PyInt_FromSsize_t(_PyWeakref_GetWeakrefCount(*list));
 21    }
 22    else
 23        result = PyInt_FromLong(0);
 24
 25    return result;
 26}
 27
 28
 29PyDoc_STRVAR(weakref_getweakrefs__doc__,
 30"getweakrefs(object) -- return a list of all weak reference objects\n"
 31"that point to 'object'.");
 32
 33static PyObject *
 34weakref_getweakrefs(PyObject *self, PyObject *object)
 35{
 36    PyObject *result = NULL;
 37
 38    if (PyType_SUPPORTS_WEAKREFS(Py_TYPE(object))) {
 39        PyWeakReference **list = GET_WEAKREFS_LISTPTR(object);
 40        Py_ssize_t count = _PyWeakref_GetWeakrefCount(*list);
 41
 42        result = PyList_New(count);
 43        if (result != NULL) {
 44            PyWeakReference *current = *list;
 45            Py_ssize_t i;
 46            for (i = 0; i < count; ++i) {
 47                PyList_SET_ITEM(result, i, (PyObject *) current);
 48                Py_INCREF(current);
 49                current = current->wr_next;
 50            }
 51        }
 52    }
 53    else {
 54        result = PyList_New(0);
 55    }
 56    return result;
 57}
 58
 59
 60PyDoc_STRVAR(weakref_proxy__doc__,
 61"proxy(object[, callback]) -- create a proxy object that weakly\n"
 62"references 'object'.  'callback', if given, is called with a\n"
 63"reference to the proxy when 'object' is about to be finalized.");
 64
 65static PyObject *
 66weakref_proxy(PyObject *self, PyObject *args)
 67{
 68    PyObject *object;
 69    PyObject *callback = NULL;
 70    PyObject *result = NULL;
 71
 72    if (PyArg_UnpackTuple(args, "proxy", 1, 2, &object, &callback)) {
 73        result = PyWeakref_NewProxy(object, callback);
 74    }
 75    return result;
 76}
 77
 78
 79static PyMethodDef
 80weakref_functions[] =  {
 81    {"getweakrefcount", weakref_getweakrefcount,        METH_O,
 82     weakref_getweakrefcount__doc__},
 83    {"getweakrefs",     weakref_getweakrefs,            METH_O,
 84     weakref_getweakrefs__doc__},
 85    {"proxy",           weakref_proxy,                  METH_VARARGS,
 86     weakref_proxy__doc__},
 87    {NULL, NULL, 0, NULL}
 88};
 89
 90
 91PyMODINIT_FUNC
 92init_weakref(void)
 93{
 94    PyObject *m;
 95
 96    m = Py_InitModule3("_weakref", weakref_functions,
 97                       "Weak-reference support module.");
 98    if (m != NULL) {
 99        Py_INCREF(&_PyWeakref_RefType);
100        PyModule_AddObject(m, "ref",
101                           (PyObject *) &_PyWeakref_RefType);
102        Py_INCREF(&_PyWeakref_RefType);
103        PyModule_AddObject(m, "ReferenceType",
104                           (PyObject *) &_PyWeakref_RefType);
105        Py_INCREF(&_PyWeakref_ProxyType);
106        PyModule_AddObject(m, "ProxyType",
107                           (PyObject *) &_PyWeakref_ProxyType);
108        Py_INCREF(&_PyWeakref_CallableProxyType);
109        PyModule_AddObject(m, "CallableProxyType",
110                           (PyObject *) &_PyWeakref_CallableProxyType);
111    }
112}