Close #18469: Replace PyDict_GetItemString() with _PyDict_GetItemId() in structseq.c

_PyDict_GetItemId() is more efficient: it only builds the Unicode string once.
Identifiers (dictionary keys) are now created at Python initialization, and if
the creation failed, Python does exit with a fatal error.

Before, PyDict_GetItemString() failure was not handled: structseq_new() could
call PyObject_GC_NewVar() with a negative size, and structseq_dealloc() could
also crash.
This commit is contained in:
Victor Stinner 2013-07-17 01:22:45 +02:00
parent b8f602a60a
commit 26f91999b4
2 changed files with 23 additions and 5 deletions

View File

@ -11,17 +11,20 @@ static char unnamed_fields_key[] = "n_unnamed_fields";
/* Fields with this name have only a field index, not a field name.
They are only allowed for indices < n_visible_fields. */
char *PyStructSequence_UnnamedField = "unnamed field";
_Py_IDENTIFIER(n_sequence_fields);
_Py_IDENTIFIER(n_fields);
_Py_IDENTIFIER(n_unnamed_fields);
#define VISIBLE_SIZE(op) Py_SIZE(op)
#define VISIBLE_SIZE_TP(tp) PyLong_AsLong( \
PyDict_GetItemString((tp)->tp_dict, visible_length_key))
_PyDict_GetItemId((tp)->tp_dict, &PyId_n_sequence_fields))
#define REAL_SIZE_TP(tp) PyLong_AsLong( \
PyDict_GetItemString((tp)->tp_dict, real_length_key))
_PyDict_GetItemId((tp)->tp_dict, &PyId_n_fields))
#define REAL_SIZE(op) REAL_SIZE_TP(Py_TYPE(op))
#define UNNAMED_FIELDS_TP(tp) PyLong_AsLong( \
PyDict_GetItemString((tp)->tp_dict, unnamed_fields_key))
_PyDict_GetItemId((tp)->tp_dict, &PyId_n_unnamed_fields))
#define UNNAMED_FIELDS(op) UNNAMED_FIELDS_TP(Py_TYPE(op))
@ -59,7 +62,7 @@ static void
structseq_dealloc(PyStructSequence *obj)
{
Py_ssize_t i, size;
size = REAL_SIZE(obj);
for (i = 0; i < size; ++i) {
Py_XDECREF(obj->ob_item[i]);
@ -382,9 +385,21 @@ PyStructSequence_InitType(PyTypeObject *type, PyStructSequence_Desc *desc)
PyTypeObject*
PyStructSequence_NewType(PyStructSequence_Desc *desc)
{
PyTypeObject *result = (PyTypeObject*)PyType_GenericAlloc(&PyType_Type, 0);
PyTypeObject *result;
result = (PyTypeObject*)PyType_GenericAlloc(&PyType_Type, 0);
if (result != NULL) {
PyStructSequence_InitType(result, desc);
}
return result;
}
int _PyStructSequence_Init(void)
{
if (_PyUnicode_FromId(&PyId_n_sequence_fields) == NULL
|| _PyUnicode_FromId(&PyId_n_fields) == NULL
|| _PyUnicode_FromId(&PyId_n_unnamed_fields) == NULL)
return -1;
return 0;
}

View File

@ -86,6 +86,7 @@ static void call_py_exitfuncs(void);
static void wait_for_thread_shutdown(void);
static void call_ll_exitfuncs(void);
extern int _PyUnicode_Init(void);
extern int _PyStructSequence_Init(void);
extern void _PyUnicode_Fini(void);
extern int _PyLong_Init(void);
extern void PyLong_Fini(void);
@ -336,6 +337,8 @@ _Py_InitializeEx_Private(int install_sigs, int install_importlib)
/* Init Unicode implementation; relies on the codec registry */
if (_PyUnicode_Init() < 0)
Py_FatalError("Py_Initialize: can't initialize unicode");
if (_PyStructSequence_Init() < 0)
Py_FatalError("Py_Initialize: can't initialize structseq");
bimod = _PyBuiltin_Init();
if (bimod == NULL)