Issue #14386: Expose the dict_proxy internal type as types.MappingProxyType

This commit is contained in:
Victor Stinner 2012-04-16 00:16:30 +02:00
parent 8a1d04c643
commit 0db176f8f6
9 changed files with 369 additions and 75 deletions

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@ -36,11 +36,11 @@ Dictionary Objects
Return a new empty dictionary, or *NULL* on failure.
.. c:function:: PyObject* PyDictProxy_New(PyObject *dict)
.. c:function:: PyObject* PyDictProxy_New(PyObject *mapping)
Return a proxy object for a mapping which enforces read-only behavior.
This is normally used to create a proxy to prevent modification of the
dictionary for non-dynamic class types.
Return a :class:`types.MappingProxyType` object for a mapping which
enforces read-only behavior. This is normally used to create a view to
prevent modification of the dictionary for non-dynamic class types.
.. c:function:: void PyDict_Clear(PyObject *p)

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@ -2258,13 +2258,13 @@ pairs within braces, for example: ``{'jack': 4098, 'sjoerd': 4127}`` or ``{4098:
.. method:: items()
Return a new view of the dictionary's items (``(key, value)`` pairs). See
below for documentation of view objects.
Return a new view of the dictionary's items (``(key, value)`` pairs).
See the :ref:`documentation of view objects <dict-views>`.
.. method:: keys()
Return a new view of the dictionary's keys. See below for documentation of
view objects.
Return a new view of the dictionary's keys. See the :ref:`documentation
of view objects <dict-views>`.
.. method:: pop(key[, default])
@ -2298,8 +2298,12 @@ pairs within braces, for example: ``{'jack': 4098, 'sjoerd': 4127}`` or ``{4098:
.. method:: values()
Return a new view of the dictionary's values. See below for documentation of
view objects.
Return a new view of the dictionary's values. See the
:ref:`documentation of view objects <dict-views>`.
.. seealso::
:class:`types.MappingProxyType` can be used to create a read-only view
of a :class:`dict`.
.. _dict-views:

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@ -85,3 +85,55 @@ The module defines the following names:
In other implementations of Python, this type may be identical to
``GetSetDescriptorType``.
.. class:: MappingProxyType(mapping)
Read-only proxy of a mapping. It provides a dynamic view on the mapping's
entries, which means that when the mapping changes, the view reflects these
changes.
.. versionadded:: 3.3
.. describe:: key in proxy
Return ``True`` if the underlying mapping has a key *key*, else
``False``.
.. describe:: proxy[key]
Return the item of the underlying mapping with key *key*. Raises a
:exc:`KeyError` if *key* is not in the underlying mapping.
.. describe:: iter(proxy)
Return an iterator over the keys of the underlying mapping. This is a
shortcut for ``iter(proxy.keys())``.
.. describe:: len(proxy)
Return the number of items in the underlying mapping.
.. method:: copy()
Return a shallow copy of the underlying mapping.
.. method:: get(key[, default])
Return the value for *key* if *key* is in the underlying mapping, else
*default*. If *default* is not given, it defaults to ``None``, so that
this method never raises a :exc:`KeyError`.
.. method:: items()
Return a new view of the underlying mapping's items (``(key, value)``
pairs).
.. method:: keys()
Return a new view of the underlying mapping's keys.
.. method:: values()
Return a new view of the underlying mapping's values.

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@ -1068,6 +1068,13 @@ The :mod:`time` module has new functions:
(Contributed by Victor Stinner in :issue:`10278`)
types
-----
Add a new :class:`types.MappingProxyType` class: Read-only proxy of a mapping.
(:issue:`14386`)
urllib
------

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@ -4574,11 +4574,11 @@ class DictProxyTests(unittest.TestCase):
self.assertEqual(type(C.__dict__), type(B.__dict__))
def test_repr(self):
# Testing dict_proxy.__repr__.
# Testing mappingproxy.__repr__.
# We can't blindly compare with the repr of another dict as ordering
# of keys and values is arbitrary and may differ.
r = repr(self.C.__dict__)
self.assertTrue(r.startswith('dict_proxy('), r)
self.assertTrue(r.startswith('mappingproxy('), r)
self.assertTrue(r.endswith(')'), r)
for k, v in self.C.__dict__.items():
self.assertIn('{!r}: {!r}'.format(k, v), r)

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@ -1,9 +1,11 @@
# Python test set -- part 6, built-in types
from test.support import run_unittest, run_with_locale
import unittest
import sys
import collections
import locale
import sys
import types
import unittest
class TypesTests(unittest.TestCase):
@ -569,8 +571,184 @@ class TypesTests(unittest.TestCase):
self.assertGreater(tuple.__itemsize__, 0)
class MappingProxyTests(unittest.TestCase):
mappingproxy = types.MappingProxyType
def test_constructor(self):
class userdict(dict):
pass
mapping = {'x': 1, 'y': 2}
self.assertEqual(self.mappingproxy(mapping), mapping)
mapping = userdict(x=1, y=2)
self.assertEqual(self.mappingproxy(mapping), mapping)
mapping = collections.ChainMap({'x': 1}, {'y': 2})
self.assertEqual(self.mappingproxy(mapping), mapping)
self.assertRaises(TypeError, self.mappingproxy, 10)
self.assertRaises(TypeError, self.mappingproxy, ("a", "tuple"))
self.assertRaises(TypeError, self.mappingproxy, ["a", "list"])
def test_methods(self):
attrs = set(dir(self.mappingproxy({}))) - set(dir(object()))
self.assertEqual(attrs, {
'__contains__',
'__getitem__',
'__iter__',
'__len__',
'copy',
'get',
'items',
'keys',
'values',
})
def test_get(self):
view = self.mappingproxy({'a': 'A', 'b': 'B'})
self.assertEqual(view['a'], 'A')
self.assertEqual(view['b'], 'B')
self.assertRaises(KeyError, view.__getitem__, 'xxx')
self.assertEqual(view.get('a'), 'A')
self.assertIsNone(view.get('xxx'))
self.assertEqual(view.get('xxx', 42), 42)
def test_missing(self):
class dictmissing(dict):
def __missing__(self, key):
return "missing=%s" % key
view = self.mappingproxy(dictmissing(x=1))
self.assertEqual(view['x'], 1)
self.assertEqual(view['y'], 'missing=y')
self.assertEqual(view.get('x'), 1)
self.assertEqual(view.get('y'), None)
self.assertEqual(view.get('y', 42), 42)
self.assertTrue('x' in view)
self.assertFalse('y' in view)
def test_customdict(self):
class customdict(dict):
def __contains__(self, key):
if key == 'magic':
return True
else:
return dict.__contains__(self, key)
def __iter__(self):
return iter(('iter',))
def __len__(self):
return 500
def copy(self):
return 'copy'
def keys(self):
return 'keys'
def items(self):
return 'items'
def values(self):
return 'values'
def __getitem__(self, key):
return "getitem=%s" % dict.__getitem__(self, key)
def get(self, key, default=None):
return "get=%s" % dict.get(self, key, 'default=%r' % default)
custom = customdict({'key': 'value'})
view = self.mappingproxy(custom)
self.assertTrue('key' in view)
self.assertTrue('magic' in view)
self.assertFalse('xxx' in view)
self.assertEqual(view['key'], 'getitem=value')
self.assertRaises(KeyError, view.__getitem__, 'xxx')
self.assertEqual(tuple(view), ('iter',))
self.assertEqual(len(view), 500)
self.assertEqual(view.copy(), 'copy')
self.assertEqual(view.get('key'), 'get=value')
self.assertEqual(view.get('xxx'), 'get=default=None')
self.assertEqual(view.items(), 'items')
self.assertEqual(view.keys(), 'keys')
self.assertEqual(view.values(), 'values')
def test_chainmap(self):
d1 = {'x': 1}
d2 = {'y': 2}
mapping = collections.ChainMap(d1, d2)
view = self.mappingproxy(mapping)
self.assertTrue('x' in view)
self.assertTrue('y' in view)
self.assertFalse('z' in view)
self.assertEqual(view['x'], 1)
self.assertEqual(view['y'], 2)
self.assertRaises(KeyError, view.__getitem__, 'z')
self.assertEqual(tuple(sorted(view)), ('x', 'y'))
self.assertEqual(len(view), 2)
copy = view.copy()
self.assertIsNot(copy, mapping)
self.assertIsInstance(copy, collections.ChainMap)
self.assertEqual(copy, mapping)
self.assertEqual(view.get('x'), 1)
self.assertEqual(view.get('y'), 2)
self.assertIsNone(view.get('z'))
self.assertEqual(tuple(sorted(view.items())), (('x', 1), ('y', 2)))
self.assertEqual(tuple(sorted(view.keys())), ('x', 'y'))
self.assertEqual(tuple(sorted(view.values())), (1, 2))
def test_contains(self):
view = self.mappingproxy(dict.fromkeys('abc'))
self.assertTrue('a' in view)
self.assertTrue('b' in view)
self.assertTrue('c' in view)
self.assertFalse('xxx' in view)
def test_views(self):
mapping = {}
view = self.mappingproxy(mapping)
keys = view.keys()
values = view.values()
items = view.items()
self.assertEqual(list(keys), [])
self.assertEqual(list(values), [])
self.assertEqual(list(items), [])
mapping['key'] = 'value'
self.assertEqual(list(keys), ['key'])
self.assertEqual(list(values), ['value'])
self.assertEqual(list(items), [('key', 'value')])
def test_len(self):
for expected in range(6):
data = dict.fromkeys('abcde'[:expected])
self.assertEqual(len(data), expected)
view = self.mappingproxy(data)
self.assertEqual(len(view), expected)
def test_iterators(self):
keys = ('x', 'y')
values = (1, 2)
items = tuple(zip(keys, values))
view = self.mappingproxy(dict(items))
self.assertEqual(set(view), set(keys))
self.assertEqual(set(view.keys()), set(keys))
self.assertEqual(set(view.values()), set(values))
self.assertEqual(set(view.items()), set(items))
def test_copy(self):
original = {'key1': 27, 'key2': 51, 'key3': 93}
view = self.mappingproxy(original)
copy = view.copy()
self.assertEqual(type(copy), dict)
self.assertEqual(copy, original)
original['key1'] = 70
self.assertEqual(view['key1'], 70)
self.assertEqual(copy['key1'], 27)
def test_main():
run_unittest(TypesTests)
run_unittest(TypesTests, MappingProxyTests)
if __name__ == '__main__':
test_main()

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@ -12,6 +12,7 @@ def _f(): pass
FunctionType = type(_f)
LambdaType = type(lambda: None) # Same as FunctionType
CodeType = type(_f.__code__)
MappingProxyType = type(type.__dict__)
def _g():
yield 1

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@ -32,6 +32,8 @@ Core and Builtins
Library
-------
- Issue #14386: Expose the dict_proxy internal type as types.MappingProxyType.
- Issue #13959: Make imp.reload() always use a module's __loader__ to perform
the reload.

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@ -698,41 +698,44 @@ PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *base, void *wrapped)
}
/* --- Readonly proxy for dictionaries (actually any mapping) --- */
/* --- mappingproxy: read-only proxy for mappings --- */
/* This has no reason to be in this file except that adding new files is a
bit of a pain */
typedef struct {
PyObject_HEAD
PyObject *dict;
} proxyobject;
PyObject *mapping;
} mappingproxyobject;
static Py_ssize_t
proxy_len(proxyobject *pp)
mappingproxy_len(mappingproxyobject *pp)
{
return PyObject_Size(pp->dict);
return PyObject_Size(pp->mapping);
}
static PyObject *
proxy_getitem(proxyobject *pp, PyObject *key)
mappingproxy_getitem(mappingproxyobject *pp, PyObject *key)
{
return PyObject_GetItem(pp->dict, key);
return PyObject_GetItem(pp->mapping, key);
}
static PyMappingMethods proxy_as_mapping = {
(lenfunc)proxy_len, /* mp_length */
(binaryfunc)proxy_getitem, /* mp_subscript */
static PyMappingMethods mappingproxy_as_mapping = {
(lenfunc)mappingproxy_len, /* mp_length */
(binaryfunc)mappingproxy_getitem, /* mp_subscript */
0, /* mp_ass_subscript */
};
static int
proxy_contains(proxyobject *pp, PyObject *key)
mappingproxy_contains(mappingproxyobject *pp, PyObject *key)
{
return PyDict_Contains(pp->dict, key);
if (PyDict_CheckExact(pp->mapping))
return PyDict_Contains(pp->mapping, key);
else
return PySequence_Contains(pp->mapping, key);
}
static PySequenceMethods proxy_as_sequence = {
static PySequenceMethods mappingproxy_as_sequence = {
0, /* sq_length */
0, /* sq_concat */
0, /* sq_repeat */
@ -740,152 +743,199 @@ static PySequenceMethods proxy_as_sequence = {
0, /* sq_slice */
0, /* sq_ass_item */
0, /* sq_ass_slice */
(objobjproc)proxy_contains, /* sq_contains */
(objobjproc)mappingproxy_contains, /* sq_contains */
0, /* sq_inplace_concat */
0, /* sq_inplace_repeat */
};
static PyObject *
proxy_get(proxyobject *pp, PyObject *args)
mappingproxy_get(mappingproxyobject *pp, PyObject *args)
{
PyObject *key, *def = Py_None;
_Py_IDENTIFIER(get);
if (!PyArg_UnpackTuple(args, "get", 1, 2, &key, &def))
return NULL;
return _PyObject_CallMethodId(pp->dict, &PyId_get, "(OO)", key, def);
return _PyObject_CallMethodId(pp->mapping, &PyId_get, "(OO)", key, def);
}
static PyObject *
proxy_keys(proxyobject *pp)
mappingproxy_keys(mappingproxyobject *pp)
{
_Py_IDENTIFIER(keys);
return _PyObject_CallMethodId(pp->dict, &PyId_keys, NULL);
return _PyObject_CallMethodId(pp->mapping, &PyId_keys, NULL);
}
static PyObject *
proxy_values(proxyobject *pp)
mappingproxy_values(mappingproxyobject *pp)
{
_Py_IDENTIFIER(values);
return _PyObject_CallMethodId(pp->dict, &PyId_values, NULL);
return _PyObject_CallMethodId(pp->mapping, &PyId_values, NULL);
}
static PyObject *
proxy_items(proxyobject *pp)
mappingproxy_items(mappingproxyobject *pp)
{
_Py_IDENTIFIER(items);
return _PyObject_CallMethodId(pp->dict, &PyId_items, NULL);
return _PyObject_CallMethodId(pp->mapping, &PyId_items, NULL);
}
static PyObject *
proxy_copy(proxyobject *pp)
mappingproxy_copy(mappingproxyobject *pp)
{
_Py_IDENTIFIER(copy);
return _PyObject_CallMethodId(pp->dict, &PyId_copy, NULL);
return _PyObject_CallMethodId(pp->mapping, &PyId_copy, NULL);
}
static PyMethodDef proxy_methods[] = {
{"get", (PyCFunction)proxy_get, METH_VARARGS,
/* WARNING: mappingproxy methods must not give access
to the underlying mapping */
static PyMethodDef mappingproxy_methods[] = {
{"get", (PyCFunction)mappingproxy_get, METH_VARARGS,
PyDoc_STR("D.get(k[,d]) -> D[k] if k in D, else d."
" d defaults to None.")},
{"keys", (PyCFunction)proxy_keys, METH_NOARGS,
" d defaults to None.")},
{"keys", (PyCFunction)mappingproxy_keys, METH_NOARGS,
PyDoc_STR("D.keys() -> list of D's keys")},
{"values", (PyCFunction)proxy_values, METH_NOARGS,
{"values", (PyCFunction)mappingproxy_values, METH_NOARGS,
PyDoc_STR("D.values() -> list of D's values")},
{"items", (PyCFunction)proxy_items, METH_NOARGS,
{"items", (PyCFunction)mappingproxy_items, METH_NOARGS,
PyDoc_STR("D.items() -> list of D's (key, value) pairs, as 2-tuples")},
{"copy", (PyCFunction)proxy_copy, METH_NOARGS,
{"copy", (PyCFunction)mappingproxy_copy, METH_NOARGS,
PyDoc_STR("D.copy() -> a shallow copy of D")},
{0}
};
static void
proxy_dealloc(proxyobject *pp)
mappingproxy_dealloc(mappingproxyobject *pp)
{
_PyObject_GC_UNTRACK(pp);
Py_DECREF(pp->dict);
Py_DECREF(pp->mapping);
PyObject_GC_Del(pp);
}
static PyObject *
proxy_getiter(proxyobject *pp)
mappingproxy_getiter(mappingproxyobject *pp)
{
return PyObject_GetIter(pp->dict);
return PyObject_GetIter(pp->mapping);
}
static PyObject *
proxy_str(proxyobject *pp)
mappingproxy_str(mappingproxyobject *pp)
{
return PyObject_Str(pp->dict);
return PyObject_Str(pp->mapping);
}
static PyObject *
proxy_repr(proxyobject *pp)
mappingproxy_repr(mappingproxyobject *pp)
{
return PyUnicode_FromFormat("dict_proxy(%R)", pp->dict);
return PyUnicode_FromFormat("mappingproxy(%R)", pp->mapping);
}
static int
proxy_traverse(PyObject *self, visitproc visit, void *arg)
mappingproxy_traverse(PyObject *self, visitproc visit, void *arg)
{
proxyobject *pp = (proxyobject *)self;
Py_VISIT(pp->dict);
mappingproxyobject *pp = (mappingproxyobject *)self;
Py_VISIT(pp->mapping);
return 0;
}
static PyObject *
proxy_richcompare(proxyobject *v, PyObject *w, int op)
mappingproxy_richcompare(mappingproxyobject *v, PyObject *w, int op)
{
return PyObject_RichCompare(v->dict, w, op);
return PyObject_RichCompare(v->mapping, w, op);
}
static int
mappingproxy_check_mapping(PyObject *mapping)
{
if (!PyMapping_Check(mapping)
|| PyList_Check(mapping)
|| PyTuple_Check(mapping)) {
PyErr_Format(PyExc_TypeError,
"mappingproxy() argument must be a mapping, not %s",
Py_TYPE(mapping)->tp_name);
return -1;
}
return 0;
}
static PyObject*
mappingproxy_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
static char *kwlist[] = {"mapping", NULL};
PyObject *mapping;
mappingproxyobject *mappingproxy;
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:mappingproxy",
kwlist, &mapping))
return NULL;
if (mappingproxy_check_mapping(mapping) == -1)
return NULL;
mappingproxy = PyObject_GC_New(mappingproxyobject, &PyDictProxy_Type);
if (mappingproxy == NULL)
return NULL;
Py_INCREF(mapping);
mappingproxy->mapping = mapping;
_PyObject_GC_TRACK(mappingproxy);
return (PyObject *)mappingproxy;
}
PyTypeObject PyDictProxy_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"dict_proxy", /* tp_name */
sizeof(proxyobject), /* tp_basicsize */
"mappingproxy", /* tp_name */
sizeof(mappingproxyobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)proxy_dealloc, /* tp_dealloc */
(destructor)mappingproxy_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
(reprfunc)proxy_repr, /* tp_repr */
(reprfunc)mappingproxy_repr, /* tp_repr */
0, /* tp_as_number */
&proxy_as_sequence, /* tp_as_sequence */
&proxy_as_mapping, /* tp_as_mapping */
&mappingproxy_as_sequence, /* tp_as_sequence */
&mappingproxy_as_mapping, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
(reprfunc)proxy_str, /* tp_str */
(reprfunc)mappingproxy_str, /* 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 */
proxy_traverse, /* tp_traverse */
mappingproxy_traverse, /* tp_traverse */
0, /* tp_clear */
(richcmpfunc)proxy_richcompare, /* tp_richcompare */
(richcmpfunc)mappingproxy_richcompare, /* tp_richcompare */
0, /* tp_weaklistoffset */
(getiterfunc)proxy_getiter, /* tp_iter */
(getiterfunc)mappingproxy_getiter, /* tp_iter */
0, /* tp_iternext */
proxy_methods, /* tp_methods */
mappingproxy_methods, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
0, /* tp_alloc */
mappingproxy_new, /* tp_new */
};
PyObject *
PyDictProxy_New(PyObject *dict)
PyDictProxy_New(PyObject *mapping)
{
proxyobject *pp;
mappingproxyobject *pp;
pp = PyObject_GC_New(proxyobject, &PyDictProxy_Type);
if (mappingproxy_check_mapping(mapping) == -1)
return NULL;
pp = PyObject_GC_New(mappingproxyobject, &PyDictProxy_Type);
if (pp != NULL) {
Py_INCREF(dict);
pp->dict = dict;
Py_INCREF(mapping);
pp->mapping = mapping;
_PyObject_GC_TRACK(pp);
}
return (PyObject *)pp;