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Add const to several API functions that take char *.

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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 *.
This commit is contained in:
Jeremy Hylton 2005-12-10 18:50:16 +00:00
parent aaa2f1dea7
commit af68c874a6
52 changed files with 272 additions and 255 deletions
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16
Objects/typeobject.c
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@ -21,7 +21,7 @@ static PyMemberDef type_members[] = {
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 @@ static PyObject *
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 @@ type_new(PyTypeObject *metatype, PyObject *args, PyObject *kwds)
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 @@ type_dealloc(PyTypeObject *type)
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);