diff options
| -rw-r--r-- | Include/object.h | 2 | ||||
| -rw-r--r-- | Objects/typeobject.c | 72 |
2 files changed, 73 insertions, 1 deletions
diff --git a/Include/object.h b/Include/object.h index e9eeb0e..8620766 100644 --- a/Include/object.h +++ b/Include/object.h @@ -289,6 +289,8 @@ typedef struct _typeobject { PyObject *tp_bases; PyObject *tp_mro; /* method resolution order */ PyObject *tp_defined; + PyObject *tp_subclasses; + PyObject *tp_weaklist; #ifdef COUNT_ALLOCS /* these must be last and never explicitly initialized */ diff --git a/Objects/typeobject.c b/Objects/typeobject.c index 0ec8175..c068548 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -1118,20 +1118,52 @@ type_dealloc(PyTypeObject *type) /* Assert this is a heap-allocated type object */ assert(type->tp_flags & Py_TPFLAGS_HEAPTYPE); _PyObject_GC_UNTRACK(type); + PyObject_ClearWeakRefs((PyObject *)type); et = (etype *)type; Py_XDECREF(type->tp_base); Py_XDECREF(type->tp_dict); Py_XDECREF(type->tp_bases); Py_XDECREF(type->tp_mro); Py_XDECREF(type->tp_defined); + Py_XDECREF(type->tp_subclasses); Py_XDECREF(et->name); Py_XDECREF(et->slots); type->ob_type->tp_free((PyObject *)type); } +static PyObject * +type_subclasses(PyTypeObject *type, PyObject *args_ignored) +{ + PyObject *list, *raw, *ref; + int i, n; + + list = PyList_New(0); + if (list == NULL) + return NULL; + raw = type->tp_subclasses; + if (raw == NULL) + return list; + assert(PyList_Check(raw)); + n = PyList_GET_SIZE(raw); + for (i = 0; i < n; i++) { + ref = PyList_GET_ITEM(raw, i); + assert(PyWeakref_CheckRef(res)); + ref = PyWeakref_GET_OBJECT(ref); + if (ref != Py_None) { + if (PyList_Append(list, ref) < 0) { + Py_DECREF(list); + return NULL; + } + } + } + return list; +} + static PyMethodDef type_methods[] = { {"mro", (PyCFunction)mro_external, METH_NOARGS, "mro() -> list\nreturn a type's method resolution order"}, + {"__subclasses__", (PyCFunction)type_subclasses, METH_NOARGS, + "__subclasses__() -> list of immediate subclasses"}, {0} }; @@ -1162,6 +1194,7 @@ type_traverse(PyTypeObject *type, visitproc visit, void *arg) VISIT(type->tp_mro); VISIT(type->tp_bases); VISIT(type->tp_base); + VISIT(type->tp_subclasses); VISIT(et->slots); #undef VISIT @@ -1192,6 +1225,7 @@ type_clear(PyTypeObject *type) CLEAR(type->tp_mro); CLEAR(type->tp_bases); CLEAR(type->tp_base); + CLEAR(type->tp_subclasses); CLEAR(et->slots); if (type->tp_doc != NULL) { @@ -1237,7 +1271,7 @@ PyTypeObject PyType_Type = { (traverseproc)type_traverse, /* tp_traverse */ (inquiry)type_clear, /* tp_clear */ 0, /* tp_richcompare */ - 0, /* tp_weaklistoffset */ + offsetof(PyTypeObject, tp_weaklist), /* tp_weaklistoffset */ 0, /* tp_iter */ 0, /* tp_iternext */ type_methods, /* tp_methods */ @@ -1741,6 +1775,7 @@ inherit_slots(PyTypeObject *type, PyTypeObject *base) } staticforward int add_operators(PyTypeObject *); +staticforward int add_subclass(PyTypeObject *base, PyTypeObject *type); int PyType_Ready(PyTypeObject *type) @@ -1858,6 +1893,15 @@ PyType_Ready(PyTypeObject *type) type->tp_as_mapping = base->tp_as_mapping; } + /* Link into each base class's list of subclasses */ + bases = type->tp_bases; + n = PyTuple_GET_SIZE(bases); + for (i = 0; i < n; i++) { + base = (PyTypeObject *) PyTuple_GET_ITEM(bases, i); + if (add_subclass((PyTypeObject *)base, type) < 0) + goto error; + } + /* All done -- set the ready flag */ assert(type->tp_dict != NULL); type->tp_flags = @@ -1869,6 +1913,32 @@ PyType_Ready(PyTypeObject *type) return -1; } +static int +add_subclass(PyTypeObject *base, PyTypeObject *type) +{ + int i; + PyObject *list, *ref, *new; + + list = base->tp_subclasses; + if (list == NULL) { + base->tp_subclasses = list = PyList_New(0); + if (list == NULL) + return -1; + } + assert(PyList_Check(list)); + new = PyWeakref_NewRef((PyObject *)type, NULL); + i = PyList_GET_SIZE(list); + while (--i >= 0) { + ref = PyList_GET_ITEM(list, i); + assert(PyWeakref_CheckRef(ref)); + if (PyWeakref_GET_OBJECT(ref) == Py_None) + return PyList_SetItem(list, i, new); + } + i = PyList_Append(list, new); + Py_DECREF(new); + return i; +} + /* Generic wrappers for overloadable 'operators' such as __getitem__ */ |