Add const to several API functions that take char *.
In C++, it's an error to pass a string literal to a char* function
without a const_cast(). Rather than require every C++ extension
module to put a cast around string literals, fix the API to state the
const-ness.
I focused on parts of the API where people usually pass literals:
PyArg_ParseTuple() and friends, Py_BuildValue(), PyMethodDef, the type
slots, etc. Predictably, there were a large set of functions that
needed to be fixed as a result of these changes. The most pervasive
change was to make the keyword args list passed to
PyArg_ParseTupleAndKewords() to be a const char *kwlist[].
One cast was required as a result of the changes: A type object
mallocs the memory for its tp_doc slot and later frees it.
PyTypeObject says that tp_doc is const char *; but if the type was
created by type_new(), we know it is safe to cast to char *.
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 591c62b..7c36ba4 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -21,7 +21,7 @@
static PyObject *
type_name(PyTypeObject *type, void *context)
{
- char *s;
+ const char *s;
if (type->tp_flags & Py_TPFLAGS_HEAPTYPE) {
PyHeapTypeObject* et = (PyHeapTypeObject*)type;
@@ -1556,7 +1556,7 @@
type_new(PyTypeObject *metatype, PyObject *args, PyObject *kwds)
{
PyObject *name, *bases, *dict;
- static char *kwlist[] = {"name", "bases", "dict", 0};
+ static const char *kwlist[] = {"name", "bases", "dict", 0};
PyObject *slots, *tmp, *newslots;
PyTypeObject *type, *base, *tmptype, *winner;
PyHeapTypeObject *et;
@@ -1856,12 +1856,13 @@
PyObject *doc = PyDict_GetItemString(dict, "__doc__");
if (doc != NULL && PyString_Check(doc)) {
const size_t n = (size_t)PyString_GET_SIZE(doc);
- type->tp_doc = (char *)PyObject_MALLOC(n+1);
- if (type->tp_doc == NULL) {
+ char *tp_doc = PyObject_MALLOC(n+1);
+ if (tp_doc == NULL) {
Py_DECREF(type);
return NULL;
}
- memcpy(type->tp_doc, PyString_AS_STRING(doc), n+1);
+ memcpy(tp_doc, PyString_AS_STRING(doc), n+1);
+ type->tp_doc = tp_doc;
}
}
@@ -2105,7 +2106,10 @@
Py_XDECREF(type->tp_mro);
Py_XDECREF(type->tp_cache);
Py_XDECREF(type->tp_subclasses);
- PyObject_Free(type->tp_doc);
+ /* A type's tp_doc is heap allocated, unlike the tp_doc slots
+ * of most other objects. It's okay to cast it to char *.
+ */
+ PyObject_Free((char *)type->tp_doc);
Py_XDECREF(et->name);
Py_XDECREF(et->slots);
type->ob_type->tp_free((PyObject *)type);