Issue #1967: Backport dictionary views.
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index af37a93..9f46dfa 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2184,6 +2184,18 @@
PyDoc_STRVAR(iteritems__doc__,
"D.iteritems() -> an iterator over the (key, value) items of D");
+/* Forward */
+static PyObject *dictkeys_new(PyObject *);
+static PyObject *dictitems_new(PyObject *);
+static PyObject *dictvalues_new(PyObject *);
+
+PyDoc_STRVAR(viewkeys__doc__,
+ "D.viewkeys() -> a set-like object providing a view on D's keys");
+PyDoc_STRVAR(viewitems__doc__,
+ "D.viewitems() -> a set-like object providing a view on D's items");
+PyDoc_STRVAR(viewvalues__doc__,
+ "D.viewvalues() -> an object providing a view on D's values");
+
static PyMethodDef mapp_methods[] = {
{"__contains__",(PyCFunction)dict_contains, METH_O | METH_COEXIST,
contains__doc__},
@@ -2207,6 +2219,12 @@
items__doc__},
{"values", (PyCFunction)dict_values, METH_NOARGS,
values__doc__},
+ {"viewkeys", (PyCFunction)dictkeys_new, METH_NOARGS,
+ viewkeys__doc__},
+ {"viewitems", (PyCFunction)dictitems_new, METH_NOARGS,
+ viewitems__doc__},
+ {"viewvalues", (PyCFunction)dictvalues_new, METH_NOARGS,
+ viewvalues__doc__},
{"update", (PyCFunction)dict_update, METH_VARARGS | METH_KEYWORDS,
update__doc__},
{"fromkeys", (PyCFunction)dict_fromkeys, METH_VARARGS | METH_CLASS,
@@ -2700,3 +2718,490 @@
dictiter_methods, /* tp_methods */
0,
};
+
+/***********************************************/
+/* View objects for keys(), items(), values(). */
+/***********************************************/
+
+/* The instance lay-out is the same for all three; but the type differs. */
+
+typedef struct {
+ PyObject_HEAD
+ PyDictObject *dv_dict;
+} dictviewobject;
+
+
+static void
+dictview_dealloc(dictviewobject *dv)
+{
+ Py_XDECREF(dv->dv_dict);
+ PyObject_GC_Del(dv);
+}
+
+static int
+dictview_traverse(dictviewobject *dv, visitproc visit, void *arg)
+{
+ Py_VISIT(dv->dv_dict);
+ return 0;
+}
+
+static Py_ssize_t
+dictview_len(dictviewobject *dv)
+{
+ Py_ssize_t len = 0;
+ if (dv->dv_dict != NULL)
+ len = dv->dv_dict->ma_used;
+ return len;
+}
+
+static PyObject *
+dictview_new(PyObject *dict, PyTypeObject *type)
+{
+ dictviewobject *dv;
+ if (dict == NULL) {
+ PyErr_BadInternalCall();
+ return NULL;
+ }
+ if (!PyDict_Check(dict)) {
+ /* XXX Get rid of this restriction later */
+ PyErr_Format(PyExc_TypeError,
+ "%s() requires a dict argument, not '%s'",
+ type->tp_name, dict->ob_type->tp_name);
+ return NULL;
+ }
+ dv = PyObject_GC_New(dictviewobject, type);
+ if (dv == NULL)
+ return NULL;
+ Py_INCREF(dict);
+ dv->dv_dict = (PyDictObject *)dict;
+ _PyObject_GC_TRACK(dv);
+ return (PyObject *)dv;
+}
+
+/* TODO(guido): The views objects are not complete:
+
+ * support more set operations
+ * support arbitrary mappings?
+ - either these should be static or exported in dictobject.h
+ - if public then they should probably be in builtins
+*/
+
+/* Return 1 if self is a subset of other, iterating over self;
+ 0 if not; -1 if an error occurred. */
+static int
+all_contained_in(PyObject *self, PyObject *other)
+{
+ PyObject *iter = PyObject_GetIter(self);
+ int ok = 1;
+
+ if (iter == NULL)
+ return -1;
+ for (;;) {
+ PyObject *next = PyIter_Next(iter);
+ if (next == NULL) {
+ if (PyErr_Occurred())
+ ok = -1;
+ break;
+ }
+ ok = PySequence_Contains(other, next);
+ Py_DECREF(next);
+ if (ok <= 0)
+ break;
+ }
+ Py_DECREF(iter);
+ return ok;
+}
+
+static PyObject *
+dictview_richcompare(PyObject *self, PyObject *other, int op)
+{
+ Py_ssize_t len_self, len_other;
+ int ok;
+ PyObject *result;
+
+ assert(self != NULL);
+ assert(PyDictViewSet_Check(self));
+ assert(other != NULL);
+
+ if (!PyAnySet_Check(other) && !PyDictViewSet_Check(other)) {
+ Py_INCREF(Py_NotImplemented);
+ return Py_NotImplemented;
+ }
+
+ len_self = PyObject_Size(self);
+ if (len_self < 0)
+ return NULL;
+ len_other = PyObject_Size(other);
+ if (len_other < 0)
+ return NULL;
+
+ ok = 0;
+ switch(op) {
+
+ case Py_NE:
+ case Py_EQ:
+ if (len_self == len_other)
+ ok = all_contained_in(self, other);
+ if (op == Py_NE && ok >= 0)
+ ok = !ok;
+ break;
+
+ case Py_LT:
+ if (len_self < len_other)
+ ok = all_contained_in(self, other);
+ break;
+
+ case Py_LE:
+ if (len_self <= len_other)
+ ok = all_contained_in(self, other);
+ break;
+
+ case Py_GT:
+ if (len_self > len_other)
+ ok = all_contained_in(other, self);
+ break;
+
+ case Py_GE:
+ if (len_self >= len_other)
+ ok = all_contained_in(other, self);
+ break;
+
+ }
+ if (ok < 0)
+ return NULL;
+ result = ok ? Py_True : Py_False;
+ Py_INCREF(result);
+ return result;
+}
+
+static PyObject *
+dictview_repr(dictviewobject *dv)
+{
+ PyObject *seq;
+ PyObject *seq_str;
+ PyObject *result;
+
+ seq = PySequence_List((PyObject *)dv);
+ if (seq == NULL)
+ return NULL;
+
+ seq_str = PyObject_Repr(seq);
+ result = PyString_FromFormat("%s(%s)", Py_TYPE(dv)->tp_name, seq_str);
+ Py_DECREF(seq_str);
+ Py_DECREF(seq);
+ return result;
+}
+
+/*** dict_keys ***/
+
+static PyObject *
+dictkeys_iter(dictviewobject *dv)
+{
+ if (dv->dv_dict == NULL) {
+ Py_RETURN_NONE;
+ }
+ return dictiter_new(dv->dv_dict, &PyDictIterKey_Type);
+}
+
+static int
+dictkeys_contains(dictviewobject *dv, PyObject *obj)
+{
+ if (dv->dv_dict == NULL)
+ return 0;
+ return PyDict_Contains((PyObject *)dv->dv_dict, obj);
+}
+
+static PySequenceMethods dictkeys_as_sequence = {
+ (lenfunc)dictview_len, /* sq_length */
+ 0, /* sq_concat */
+ 0, /* sq_repeat */
+ 0, /* sq_item */
+ 0, /* sq_slice */
+ 0, /* sq_ass_item */
+ 0, /* sq_ass_slice */
+ (objobjproc)dictkeys_contains, /* sq_contains */
+};
+
+static PyObject*
+dictviews_sub(PyObject* self, PyObject *other)
+{
+ PyObject *result = PySet_New(self);
+ PyObject *tmp;
+ if (result == NULL)
+ return NULL;
+
+ tmp = PyObject_CallMethod(result, "difference_update", "O", other);
+ if (tmp == NULL) {
+ Py_DECREF(result);
+ return NULL;
+ }
+
+ Py_DECREF(tmp);
+ return result;
+}
+
+static PyObject*
+dictviews_and(PyObject* self, PyObject *other)
+{
+ PyObject *result = PySet_New(self);
+ PyObject *tmp;
+ if (result == NULL)
+ return NULL;
+
+ tmp = PyObject_CallMethod(result, "intersection_update", "O", other);
+ if (tmp == NULL) {
+ Py_DECREF(result);
+ return NULL;
+ }
+
+ Py_DECREF(tmp);
+ return result;
+}
+
+static PyObject*
+dictviews_or(PyObject* self, PyObject *other)
+{
+ PyObject *result = PySet_New(self);
+ PyObject *tmp;
+ if (result == NULL)
+ return NULL;
+
+ tmp = PyObject_CallMethod(result, "update", "O", other);
+ if (tmp == NULL) {
+ Py_DECREF(result);
+ return NULL;
+ }
+
+ Py_DECREF(tmp);
+ return result;
+}
+
+static PyObject*
+dictviews_xor(PyObject* self, PyObject *other)
+{
+ PyObject *result = PySet_New(self);
+ PyObject *tmp;
+ if (result == NULL)
+ return NULL;
+
+ tmp = PyObject_CallMethod(result, "symmetric_difference_update", "O",
+ other);
+ if (tmp == NULL) {
+ Py_DECREF(result);
+ return NULL;
+ }
+
+ Py_DECREF(tmp);
+ return result;
+}
+
+static PyNumberMethods dictviews_as_number = {
+ 0, /*nb_add*/
+ (binaryfunc)dictviews_sub, /*nb_subtract*/
+ 0, /*nb_multiply*/
+ 0, /*nb_remainder*/
+ 0, /*nb_divmod*/
+ 0, /*nb_power*/
+ 0, /*nb_negative*/
+ 0, /*nb_positive*/
+ 0, /*nb_absolute*/
+ 0, /*nb_bool*/
+ 0, /*nb_invert*/
+ 0, /*nb_lshift*/
+ 0, /*nb_rshift*/
+ (binaryfunc)dictviews_and, /*nb_and*/
+ (binaryfunc)dictviews_xor, /*nb_xor*/
+ (binaryfunc)dictviews_or, /*nb_or*/
+};
+
+static PyMethodDef dictkeys_methods[] = {
+ {NULL, NULL} /* sentinel */
+};
+
+PyTypeObject PyDictKeys_Type = {
+ PyVarObject_HEAD_INIT(&PyType_Type, 0)
+ "dict_keys", /* tp_name */
+ sizeof(dictviewobject), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ /* methods */
+ (destructor)dictview_dealloc, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_reserved */
+ (reprfunc)dictview_repr, /* tp_repr */
+ &dictviews_as_number, /* tp_as_number */
+ &dictkeys_as_sequence, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ PyObject_GenericGetAttr, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
+ 0, /* tp_doc */
+ (traverseproc)dictview_traverse, /* tp_traverse */
+ 0, /* tp_clear */
+ dictview_richcompare, /* tp_richcompare */
+ 0, /* tp_weaklistoffset */
+ (getiterfunc)dictkeys_iter, /* tp_iter */
+ 0, /* tp_iternext */
+ dictkeys_methods, /* tp_methods */
+ 0,
+};
+
+static PyObject *
+dictkeys_new(PyObject *dict)
+{
+ return dictview_new(dict, &PyDictKeys_Type);
+}
+
+/*** dict_items ***/
+
+static PyObject *
+dictitems_iter(dictviewobject *dv)
+{
+ if (dv->dv_dict == NULL) {
+ Py_RETURN_NONE;
+ }
+ return dictiter_new(dv->dv_dict, &PyDictIterItem_Type);
+}
+
+static int
+dictitems_contains(dictviewobject *dv, PyObject *obj)
+{
+ PyObject *key, *value, *found;
+ if (dv->dv_dict == NULL)
+ return 0;
+ if (!PyTuple_Check(obj) || PyTuple_GET_SIZE(obj) != 2)
+ return 0;
+ key = PyTuple_GET_ITEM(obj, 0);
+ value = PyTuple_GET_ITEM(obj, 1);
+ found = PyDict_GetItem((PyObject *)dv->dv_dict, key);
+ if (found == NULL) {
+ if (PyErr_Occurred())
+ return -1;
+ return 0;
+ }
+ return PyObject_RichCompareBool(value, found, Py_EQ);
+}
+
+static PySequenceMethods dictitems_as_sequence = {
+ (lenfunc)dictview_len, /* sq_length */
+ 0, /* sq_concat */
+ 0, /* sq_repeat */
+ 0, /* sq_item */
+ 0, /* sq_slice */
+ 0, /* sq_ass_item */
+ 0, /* sq_ass_slice */
+ (objobjproc)dictitems_contains, /* sq_contains */
+};
+
+static PyMethodDef dictitems_methods[] = {
+ {NULL, NULL} /* sentinel */
+};
+
+PyTypeObject PyDictItems_Type = {
+ PyVarObject_HEAD_INIT(&PyType_Type, 0)
+ "dict_items", /* tp_name */
+ sizeof(dictviewobject), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ /* methods */
+ (destructor)dictview_dealloc, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_reserved */
+ (reprfunc)dictview_repr, /* tp_repr */
+ &dictviews_as_number, /* tp_as_number */
+ &dictitems_as_sequence, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ PyObject_GenericGetAttr, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
+ 0, /* tp_doc */
+ (traverseproc)dictview_traverse, /* tp_traverse */
+ 0, /* tp_clear */
+ dictview_richcompare, /* tp_richcompare */
+ 0, /* tp_weaklistoffset */
+ (getiterfunc)dictitems_iter, /* tp_iter */
+ 0, /* tp_iternext */
+ dictitems_methods, /* tp_methods */
+ 0,
+};
+
+static PyObject *
+dictitems_new(PyObject *dict)
+{
+ return dictview_new(dict, &PyDictItems_Type);
+}
+
+/*** dict_values ***/
+
+static PyObject *
+dictvalues_iter(dictviewobject *dv)
+{
+ if (dv->dv_dict == NULL) {
+ Py_RETURN_NONE;
+ }
+ return dictiter_new(dv->dv_dict, &PyDictIterValue_Type);
+}
+
+static PySequenceMethods dictvalues_as_sequence = {
+ (lenfunc)dictview_len, /* sq_length */
+ 0, /* sq_concat */
+ 0, /* sq_repeat */
+ 0, /* sq_item */
+ 0, /* sq_slice */
+ 0, /* sq_ass_item */
+ 0, /* sq_ass_slice */
+ (objobjproc)0, /* sq_contains */
+};
+
+static PyMethodDef dictvalues_methods[] = {
+ {NULL, NULL} /* sentinel */
+};
+
+PyTypeObject PyDictValues_Type = {
+ PyVarObject_HEAD_INIT(&PyType_Type, 0)
+ "dict_values", /* tp_name */
+ sizeof(dictviewobject), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ /* methods */
+ (destructor)dictview_dealloc, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_reserved */
+ (reprfunc)dictview_repr, /* tp_repr */
+ 0, /* tp_as_number */
+ &dictvalues_as_sequence, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ PyObject_GenericGetAttr, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
+ 0, /* tp_doc */
+ (traverseproc)dictview_traverse, /* tp_traverse */
+ 0, /* tp_clear */
+ 0, /* tp_richcompare */
+ 0, /* tp_weaklistoffset */
+ (getiterfunc)dictvalues_iter, /* tp_iter */
+ 0, /* tp_iternext */
+ dictvalues_methods, /* tp_methods */
+ 0,
+};
+
+static PyObject *
+dictvalues_new(PyObject *dict)
+{
+ return dictview_new(dict, &PyDictValues_Type);
+}