Patch #1591665: implement the __dir__() special function lookup in PyObject_Dir.
diff --git a/Objects/object.c b/Objects/object.c
index 065abdc..e2d1b13 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -1284,6 +1284,8 @@
return x->ob_type->tp_call != NULL;
}
+/* ------------------------- PyObject_Dir() helpers ------------------------- */
+
/* Helper for PyObject_Dir.
Merge the __dict__ of aclass into dict, and recursively also all
the __dict__s of aclass's base classes. The order of merging isn't
@@ -1343,158 +1345,174 @@
return 0;
}
-/* Helper for PyObject_Dir.
- If obj has an attr named attrname that's a list, merge its string
- elements into keys of dict.
- Return 0 on success, -1 on error. Errors due to not finding the attr,
- or the attr not being a list, are suppressed.
-*/
-
-static int
-merge_list_attr(PyObject* dict, PyObject* obj, const char *attrname)
+/* Helper for PyObject_Dir without arguments: returns the local scope. */
+static PyObject *
+_dir_locals()
{
- PyObject *list;
- int result = 0;
+ PyObject *locals = PyEval_GetLocals();
- assert(PyDict_Check(dict));
- assert(obj);
- assert(attrname);
-
- list = PyObject_GetAttrString(obj, attrname);
- if (list == NULL)
- PyErr_Clear();
-
- else if (PyList_Check(list)) {
- int i;
- for (i = 0; i < PyList_GET_SIZE(list); ++i) {
- PyObject *item = PyList_GET_ITEM(list, i);
- if (PyString_Check(item)) {
- result = PyDict_SetItem(dict, item, Py_None);
- if (result < 0)
- break;
- }
- }
+ if (locals == NULL) {
+ PyErr_SetString(PyExc_SystemError, "frame does not exist");
+ return NULL;
}
- Py_XDECREF(list);
+ /* the locals don't need to be DECREF'd */
+ return PyMapping_Keys(locals);
+}
+
+/* Helper for PyObject_Dir of type objects: returns __dict__ and __bases__.
+ We deliberately don't suck up its __class__, as methods belonging to the
+ metaclass would probably be more confusing than helpful.
+*/
+static PyObject *
+_specialized_dir_type(PyObject *obj)
+{
+ PyObject *result = NULL;
+ PyObject *dict = PyDict_New();
+
+ if (dict != NULL && merge_class_dict(dict, obj) == 0)
+ result = PyDict_Keys(dict);
+
+ Py_XDECREF(dict);
return result;
}
-/* Like __builtin__.dir(arg). See bltinmodule.c's builtin_dir for the
- docstring, which should be kept in synch with this implementation. */
-
-PyObject *
-PyObject_Dir(PyObject *arg)
+/* Helper for PyObject_Dir of module objects: returns the module's __dict__. */
+static PyObject *
+_specialized_dir_module(PyObject *obj)
{
- /* Set exactly one of these non-NULL before the end. */
- PyObject *result = NULL; /* result list */
- PyObject *masterdict = NULL; /* result is masterdict.keys() */
+ PyObject *result = NULL;
+ PyObject *dict = PyObject_GetAttrString(obj, "__dict__");
- /* If NULL arg, return the locals. */
- if (arg == NULL) {
- PyObject *locals = PyEval_GetLocals();
- if (locals == NULL)
- goto error;
- result = PyMapping_Keys(locals);
- if (result == NULL)
- goto error;
- }
-
- /* Elif this is some form of module, we only want its dict. */
- else if (PyModule_Check(arg)) {
- masterdict = PyObject_GetAttrString(arg, "__dict__");
- if (masterdict == NULL)
- goto error;
- if (!PyDict_Check(masterdict)) {
- PyErr_SetString(PyExc_TypeError,
- "module.__dict__ is not a dictionary");
- goto error;
+ if (dict != NULL) {
+ if (PyDict_Check(dict))
+ result = PyDict_Keys(dict);
+ else {
+ PyErr_Format(PyExc_TypeError,
+ "%.200s.__dict__ is not a dictionary",
+ PyModule_GetName(obj));
}
}
- /* Elif some form of type or class, grab its dict and its bases.
- We deliberately don't suck up its __class__, as methods belonging
- to the metaclass would probably be more confusing than helpful. */
- else if (PyType_Check(arg)) {
- masterdict = PyDict_New();
- if (masterdict == NULL)
- goto error;
- if (merge_class_dict(masterdict, arg) < 0)
- goto error;
- }
+ Py_XDECREF(dict);
+ return result;
+}
- /* Else look at its dict, and the attrs reachable from its class. */
+/* Helper for PyObject_Dir of generic objects: returns __dict__, __class__,
+ and recursively up the __class__.__bases__ chain.
+*/
+static PyObject *
+_generic_dir(PyObject *obj)
+{
+ PyObject *result = NULL;
+ PyObject *dict = NULL;
+ PyObject *itsclass = NULL;
+
+ /* Get __dict__ (which may or may not be a real dict...) */
+ dict = PyObject_GetAttrString(obj, "__dict__");
+ if (dict == NULL) {
+ PyErr_Clear();
+ dict = PyDict_New();
+ }
+ else if (!PyDict_Check(dict)) {
+ Py_DECREF(dict);
+ dict = PyDict_New();
+ }
else {
- PyObject *itsclass;
- /* Create a dict to start with. CAUTION: Not everything
- responding to __dict__ returns a dict! */
- masterdict = PyObject_GetAttrString(arg, "__dict__");
- if (masterdict == NULL) {
- PyErr_Clear();
- masterdict = PyDict_New();
- }
- else if (!PyDict_Check(masterdict)) {
- Py_DECREF(masterdict);
- masterdict = PyDict_New();
- }
- else {
- /* The object may have returned a reference to its
- dict, so copy it to avoid mutating it. */
- PyObject *temp = PyDict_Copy(masterdict);
- Py_DECREF(masterdict);
- masterdict = temp;
- }
- if (masterdict == NULL)
- goto error;
-
- /* Merge in __members__ and __methods__ (if any).
- XXX Would like this to go away someday; for now, it's
- XXX needed to get at im_self etc of method objects. */
- if (merge_list_attr(masterdict, arg, "__members__") < 0)
- goto error;
- if (merge_list_attr(masterdict, arg, "__methods__") < 0)
- goto error;
-
- /* Merge in attrs reachable from its class.
- CAUTION: Not all objects have a __class__ attr. */
- itsclass = PyObject_GetAttrString(arg, "__class__");
- if (itsclass == NULL)
- PyErr_Clear();
- else {
- int status = merge_class_dict(masterdict, itsclass);
- Py_DECREF(itsclass);
- if (status < 0)
- goto error;
- }
+ /* Copy __dict__ to avoid mutating it. */
+ PyObject *temp = PyDict_Copy(dict);
+ Py_DECREF(dict);
+ dict = temp;
}
- assert((result == NULL) ^ (masterdict == NULL));
- if (masterdict != NULL) {
- /* The result comes from its keys. */
- assert(result == NULL);
- result = PyDict_Keys(masterdict);
- if (result == NULL)
- goto error;
- }
-
- assert(result);
- if (!PyList_Check(result)) {
- PyErr_Format(PyExc_TypeError,
- "Expected keys() to be a list, not '%.200s'",
- result->ob_type->tp_name);
+ if (dict == NULL)
goto error;
- }
- if (PyList_Sort(result) != 0)
- goto error;
- else
- goto normal_return;
- error:
- Py_XDECREF(result);
- result = NULL;
+ /* Merge in attrs reachable from its class. */
+ itsclass = PyObject_GetAttrString(obj, "__class__");
+ if (itsclass == NULL)
+ /* XXX(tomer): Perhaps fall back to obj->ob_type if no
+ __class__ exists? */
+ PyErr_Clear();
+ else {
+ if (merge_class_dict(dict, itsclass) != 0)
+ goto error;
+ }
+
+ result = PyDict_Keys(dict);
/* fall through */
- normal_return:
- Py_XDECREF(masterdict);
+error:
+ Py_XDECREF(itsclass);
+ Py_XDECREF(dict);
+ return result;
+}
+
+/* Helper for PyObject_Dir: object introspection.
+ This calls one of the above specialized versions if no __dir__ method
+ exists. */
+static PyObject *
+_dir_object(PyObject *obj)
+{
+ PyObject * result = NULL;
+ PyObject * dirfunc = PyObject_GetAttrString((PyObject*)obj->ob_type,
+ "__dir__");
+
+ assert(obj);
+ if (dirfunc == NULL) {
+ /* use default implementation */
+ PyErr_Clear();
+ if (PyModule_Check(obj))
+ result = _specialized_dir_module(obj);
+ else if (PyType_Check(obj))
+ result = _specialized_dir_type(obj);
+ else
+ result = _generic_dir(obj);
+ }
+ else {
+ /* use __dir__ */
+ result = PyObject_CallFunctionObjArgs(dirfunc, obj, NULL);
+ Py_DECREF(dirfunc);
+ if (result == NULL)
+ return NULL;
+
+ /* result must be a list */
+ /* XXX(gbrandl): could also check if all items are strings */
+ if (!PyList_Check(result)) {
+ PyErr_Format(PyExc_TypeError,
+ "__dir__() must return a list, not %.200s",
+ result->ob_type->tp_name);
+ Py_DECREF(result);
+ result = NULL;
+ }
+ }
+
+ return result;
+}
+
+/* Implementation of dir() -- if obj is NULL, returns the names in the current
+ (local) scope. Otherwise, performs introspection of the object: returns a
+ sorted list of attribute names (supposedly) accessible from the object
+*/
+PyObject *
+PyObject_Dir(PyObject *obj)
+{
+ PyObject * result;
+
+ if (obj == NULL)
+ /* no object -- introspect the locals */
+ result = _dir_locals();
+ else
+ /* object -- introspect the object */
+ result = _dir_object(obj);
+
+ assert(result == NULL || PyList_Check(result));
+
+ if (result != NULL && PyList_Sort(result) != 0) {
+ /* sorting the list failed */
+ Py_DECREF(result);
+ result = NULL;
+ }
+
return result;
}