SF bug 433228: repr(list) woes when len(list) big.
Gave Python linear-time repr() implementations for dicts, lists, strings.
This means, e.g., that repr(range(50000)) is no longer 50x slower than
pprint.pprint() in 2.2 <wink>.
I don't consider this a bugfix candidate, as it's a performance boost.
Added _PyString_Join() to the internal string API. If we want that in the
public API, fine, but then it requires runtime error checks instead of
asserts.
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 21cc6c6..42bfd40 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -809,42 +809,80 @@
static PyObject *
dict_repr(dictobject *mp)
{
- auto PyObject *v;
- PyObject *sepa, *colon;
- register int i;
- register int any;
+ int i, pos;
+ PyObject *s, *temp, *colon = NULL;
+ PyObject *pieces = NULL, *result = NULL;
+ PyObject *key, *value;
- i = Py_ReprEnter((PyObject*)mp);
+ i = Py_ReprEnter((PyObject *)mp);
if (i != 0) {
- if (i > 0)
- return PyString_FromString("{...}");
- return NULL;
+ return i > 0 ? PyString_FromString("{...}") : NULL;
}
- v = PyString_FromString("{");
- sepa = PyString_FromString(", ");
- colon = PyString_FromString(": ");
- any = 0;
- for (i = 0; i <= mp->ma_mask && v; i++) {
- dictentry *ep = mp->ma_table + i;
- PyObject *pvalue = ep->me_value;
- if (pvalue != NULL) {
- /* Prevent PyObject_Repr from deleting value during
- key format */
- Py_INCREF(pvalue);
- if (any++)
- PyString_Concat(&v, sepa);
- PyString_ConcatAndDel(&v, PyObject_Repr(ep->me_key));
- PyString_Concat(&v, colon);
- PyString_ConcatAndDel(&v, PyObject_Repr(pvalue));
- Py_DECREF(pvalue);
- }
+ if (mp->ma_used == 0) {
+ result = PyString_FromString("{}");
+ goto Done;
}
- PyString_ConcatAndDel(&v, PyString_FromString("}"));
- Py_ReprLeave((PyObject*)mp);
- Py_XDECREF(sepa);
+
+ pieces = PyList_New(0);
+ if (pieces == NULL)
+ goto Done;
+
+ colon = PyString_FromString(": ");
+ if (colon == NULL)
+ goto Done;
+
+ /* Do repr() on each key+value pair, and insert ": " between them.
+ Note that repr may mutate the dict. */
+ pos = 0;
+ while (PyDict_Next((PyObject *)mp, &pos, &key, &value)) {
+ int status;
+ /* Prevent repr from deleting value during key format. */
+ Py_INCREF(value);
+ s = PyObject_Repr(key);
+ PyString_Concat(&s, colon);
+ PyString_ConcatAndDel(&s, PyObject_Repr(value));
+ Py_DECREF(value);
+ if (s == NULL)
+ goto Done;
+ status = PyList_Append(pieces, s);
+ Py_DECREF(s); /* append created a new ref */
+ if (status < 0)
+ goto Done;
+ }
+
+ /* Add "{}" decorations to the first and last items. */
+ assert(PyList_GET_SIZE(pieces) > 0);
+ s = PyString_FromString("{");
+ if (s == NULL)
+ goto Done;
+ temp = PyList_GET_ITEM(pieces, 0);
+ PyString_ConcatAndDel(&s, temp);
+ PyList_SET_ITEM(pieces, 0, s);
+ if (s == NULL)
+ goto Done;
+
+ s = PyString_FromString("}");
+ if (s == NULL)
+ goto Done;
+ temp = PyList_GET_ITEM(pieces, PyList_GET_SIZE(pieces) - 1);
+ PyString_ConcatAndDel(&temp, s);
+ PyList_SET_ITEM(pieces, PyList_GET_SIZE(pieces) - 1, temp);
+ if (temp == NULL)
+ goto Done;
+
+ /* Paste them all together with ", " between. */
+ s = PyString_FromString(", ");
+ if (s == NULL)
+ goto Done;
+ result = _PyString_Join(s, pieces);
+ Py_DECREF(s);
+
+Done:
+ Py_XDECREF(pieces);
Py_XDECREF(colon);
- return v;
+ Py_ReprLeave((PyObject *)mp);
+ return result;
}
static int