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Issue #12911: Fix memory consumption when calculating the repr() of huge tuples or lists.

Browse source 
This introduces a small private API for this common pattern.
The issue has been discovered thanks to Martin's huge-mem buildbot.
This commit is contained in:
Antoine Pitrou 2011-10-06 19:04:12 +02:00
commit c61c8d7a5e
13 changed files with 270 additions and 86 deletions
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75
Objects/tupleobject.c
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@ -240,13 +240,20 @@ static PyObject *
tuplerepr(PyTupleObject *v)
{
Py_ssize_t i, n;
PyObject *s, *temp;
PyObject *pieces, *result = NULL;
PyObject *s = NULL;
_PyAccu acc;
static PyObject *sep = NULL;
n = Py_SIZE(v);
if (n == 0)
return PyUnicode_FromString("()");
if (sep == NULL) {
sep = PyUnicode_FromString(", ");
if (sep == NULL)
return NULL;
}
/* While not mutable, it is still possible to end up with a cycle in a
tuple through an object that stores itself within a tuple (and thus
infinitely asks for the repr of itself). This should only be
@ -256,52 +263,42 @@ tuplerepr(PyTupleObject *v)
return i > 0 ? PyUnicode_FromString("(...)") : NULL;
}
pieces = PyTuple_New(n);
if (pieces == NULL)
return NULL;
if (_PyAccu_Init(&acc))
goto error;
s = PyUnicode_FromString("(");
if (s == NULL || _PyAccu_Accumulate(&acc, s))
goto error;
Py_CLEAR(s);
/* Do repr() on each element. */
for (i = 0; i < n; ++i) {
if (Py_EnterRecursiveCall(" while getting the repr of a tuple"))
goto Done;
goto error;
s = PyObject_Repr(v->ob_item[i]);
Py_LeaveRecursiveCall();
if (s == NULL)
goto Done;
PyTuple_SET_ITEM(pieces, i, s);
if (i > 0 && _PyAccu_Accumulate(&acc, sep))
goto error;
if (s == NULL || _PyAccu_Accumulate(&acc, s))
goto error;
Py_CLEAR(s);
}
if (n > 1)
s = PyUnicode_FromString(")");
else
s = PyUnicode_FromString(",)");
if (s == NULL || _PyAccu_Accumulate(&acc, s))
goto error;
Py_CLEAR(s);
/* Add "()" decorations to the first and last items. */
assert(n > 0);
s = PyUnicode_FromString("(");
if (s == NULL)
goto Done;
temp = PyTuple_GET_ITEM(pieces, 0);
PyUnicode_AppendAndDel(&s, temp);
PyTuple_SET_ITEM(pieces, 0, s);
if (s == NULL)
goto Done;
s = PyUnicode_FromString(n == 1 ? ",)" : ")");
if (s == NULL)
goto Done;
temp = PyTuple_GET_ITEM(pieces, n-1);
PyUnicode_AppendAndDel(&temp, s);
PyTuple_SET_ITEM(pieces, n-1, temp);
if (temp == NULL)
goto Done;
/* Paste them all together with ", " between. */
s = PyUnicode_FromString(", ");
if (s == NULL)
goto Done;
result = PyUnicode_Join(s, pieces);
Py_DECREF(s);
Done:
Py_DECREF(pieces);
Py_ReprLeave((PyObject *)v);
return result;
return _PyAccu_Finish(&acc);
error:
_PyAccu_Destroy(&acc);
Py_XDECREF(s);
Py_ReprLeave((PyObject *)v);
return NULL;
}
/* The addend 82520, was selected from the range(0, 1000000) for