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Issue #18594: Fix the fallback path in collections.Counter().

This commit is contained in:
Raymond Hettinger 2013-10-01 21:36:09 -07:00
parent 1a33b2f35b
commit 224c87d60c
2 changed files with 25 additions and 19 deletions
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3
Misc/NEWS
View File

@ -79,7 +79,8 @@ Library
when necessary. Patch by Oscar Benjamin.
- Issue #18594: The fast path for collections.Counter() was never taken
due to an over-restrictive type check.
due to an over-restrictive type check. And the fallback path did
not implement the same algorithm as the pure python code.
- Properly initialize all fields of a SSL object after allocation.

41
Modules/_collectionsmodule.c
View File

@ -1694,7 +1694,9 @@ _count_elements(PyObject *self, PyObject *args)
PyObject *it, *iterable, *mapping, *oldval;
PyObject *newval = NULL;
PyObject *key = NULL;
PyObject *zero = NULL;
PyObject *one = NULL;
PyObject *mapping_get = NULL;
PyObject *mapping_getitem;
PyObject *mapping_setitem;
PyObject *dict_getitem;
@ -1708,10 +1710,8 @@ _count_elements(PyObject *self, PyObject *args)
return NULL;
one = PyLong_FromLong(1);
if (one == NULL) {
Py_DECREF(it);
return NULL;
}
if (one == NULL)
goto done;
mapping_getitem = _PyType_LookupId(Py_TYPE(mapping), &PyId___getitem__);
dict_getitem = _PyType_LookupId(&PyDict_Type, &PyId___getitem__);
@ -1741,23 +1741,25 @@ _count_elements(PyObject *self, PyObject *args)
Py_DECREF(key);
}
} else {
mapping_get = PyObject_GetAttrString(mapping, "get");
if (mapping_get == NULL)
goto done;
zero = PyLong_FromLong(0);
if (zero == NULL)
goto done;
while (1) {
key = PyIter_Next(it);
if (key == NULL)
break;
oldval = PyObject_GetItem(mapping, key);
if (oldval == NULL) {
if (!PyErr_Occurred() || !PyErr_ExceptionMatches(PyExc_KeyError))
break;
PyErr_Clear();
Py_INCREF(one);
newval = one;
} else {
newval = PyNumber_Add(oldval, one);
Py_DECREF(oldval);
if (newval == NULL)
break;
}
oldval = PyObject_CallFunctionObjArgs(mapping_get, key, zero, NULL);
if (oldval == NULL)
break;
newval = PyNumber_Add(oldval, one);
Py_DECREF(oldval);
if (newval == NULL)
break;
if (PyObject_SetItem(mapping, key, newval) == -1)
break;
Py_CLEAR(newval);
@ -1765,10 +1767,13 @@ _count_elements(PyObject *self, PyObject *args)
}
}
done:
Py_DECREF(it);
Py_XDECREF(key);
Py_XDECREF(newval);
Py_DECREF(one);
Py_XDECREF(mapping_get);
Py_XDECREF(zero);
Py_XDECREF(one);
if (PyErr_Occurred())
return NULL;
Py_RETURN_NONE;