Re: [pygame] memory leaks with Py_BuildValue

["Campbell Barton" <ideasman42@xxxxxxxxx>]

Thanks for submitting, Is there anything wrong with the mouse patch I
submitted earlier? - from my testing it definitely leaks and the patch
fixes it.

On Fri, Sep 5, 2008 at 3:29 PM, Nirav Patel <olpc@xxxxxxxxxxxxxx> wrote:
> Thanks!  Patch committed.
>
> Nirav
>
> On Wed, Sep 3, 2008 at 7:10 PM, Campbell Barton <ideasman42@xxxxxxxxx> wrote:
>> Heres more fixes to mask.c - Py_BuildValue returns a variable with 1
>> ref and PyList_Append adds another. checked all other cases of
>> PyList_Append and they all seem correct.
>>
>> Index: src/mask.c
>> ===================================================================
>> --- src/mask.c  (revision 1646)
>> +++ src/mask.c  (working copy)
>> @@ -312,7 +312,7 @@
>>  {
>>     bitmask_t* c = PyMask_AsBitmap(self);
>>     bitmask_t* m = bitmask_create(c->w + 2, c->h + 2);
>> -    PyObject* plist;
>> +    PyObject* plist, *value;
>>     int x, y, every, e, firstx, firsty, secx, secy, currx, curry,
>> nextx, nexty, n;
>>     int a[14], b[14];
>>     a[0] = a[1] = a[7] = a[8] = a[9] = b[1] = b[2] = b[3] = b[9] =
>> b[10] = b[11]= 1;
>> @@ -343,7 +343,9 @@
>>             if (bitmask_getbit(m, x, y)) {
>>                  firstx = x;
>>                  firsty = y;
>> -                 PyList_Append(plist, Py_BuildValue("(ii)", x-1, y-1));
>> +                 value = Py_BuildValue("(ii)", x-1, y-1);
>> +                 PyList_Append(plist, value);
>> +                 Py_DECREF(value);
>>                  break;
>>             }
>>         }
>> @@ -367,7 +369,9 @@
>>             e--;
>>             if (!e) {
>>                 e = every;
>> -                PyList_Append(plist, Py_BuildValue("(ii)", secx-1, secy-1));
>> +                value = Py_BuildValue("(ii)", secx-1, secy-1);
>> +                PyList_Append(plist, value);
>> +                Py_DECREF(value);
>>             }
>>             break;
>>         }
>> @@ -392,7 +396,9 @@
>>                     if ((curry == firsty && currx == firstx) && (secx
>> == nextx && secy == nexty)) {
>>                         break;
>>                     }
>> -                    PyList_Append(plist, Py_BuildValue("(ii)",
>> nextx-1, nexty-1));
>> +                                       value = Py_BuildValue("(ii)", nextx-1, nexty-1);
>> +                    PyList_Append(plist, value);
>> +                                       Py_DECREF(value);
>>                 }
>>                 break;
>>             }
>> @@ -1170,6 +1176,7 @@
>>         if(maskobj) {
>>             maskobj->mask = components[i];
>>             PyList_Append (ret, (PyObject *) maskobj);
>> +                       Py_DECREF((PyObject *) maskobj);
>>         }
>>     }
>>
>>
>>
>>
>> On Thu, Sep 4, 2008 at 1:51 AM, Nirav Patel <olpc@xxxxxxxxxxxxxx> wrote:
>>> Thanks,
>>>
>>> I just committed a fix for it in mask.c.
>>>
>>> Nirav
>>>
>>> On Wed, Sep 3, 2008 at 11:13 AM, Campbell Barton <ideasman42@xxxxxxxxx> wrote:
>>>> Hi, over a year ago I had a look at pygames py-c/api usage for memory
>>>> leaks, and found a few, mainly with Py_BuildValue() using PyObjects
>>>> which are incref'd,
>>>> had another look at the recent SVN and found some more, not sure if
>>>> they are new but they definitely cause memory leaks.
>>>>
>>>> For example - call pygame.mouse.get_cursor() in a loop of 10000 for
>>>> every update in chimp.py and memory will go up 100's of meg fairly
>>>> fast, patch below.
>>>>
>>>> you also might want to consider using PyTuple_Pack() which is faster
>>>> but only in python 2.4 or later.
>>>> http://docs.python.org/api/tupleObjects.html#l2h-583
>>>>
>>>>
>>>> These leak too, much the same changes need to be made here also.
>>>> ./src/mask.c:265:        return Py_BuildValue ("(OO)", PyInt_FromLong(m10/m00),
>>>> ./src/mask.c:268:        return Py_BuildValue ("(OO)",
>>>> PyInt_FromLong(0), PyInt_FromLong(0));
>>>> ./src/mask.c:298:        return Py_BuildValue ("O", PyFloat_FromDouble(theta));
>>>> ./src/mask.c:300:        return Py_BuildValue ("O", PyFloat_FromDouble(0));
>>>>
>>>>
>>>> Index: src/mouse.c
>>>> ===================================================================
>>>> --- src/mouse.c (revision 1645)
>>>> +++ src/mouse.c (working copy)
>>>> @@ -171,7 +171,7 @@
>>>>  mouse_get_cursor (PyObject* self)
>>>>  {
>>>>     SDL_Cursor *cursor = NULL;
>>>> -    PyObject* xordata, *anddata;
>>>> +    PyObject* xordata, *anddata, *ret;
>>>>     int size, loop, w, h, spotx, spoty;
>>>>
>>>>     VIDEO_INIT_CHECK ();
>>>> @@ -201,8 +201,10 @@
>>>>         PyTuple_SET_ITEM (xordata, loop, PyInt_FromLong (cursor->data[loop]));
>>>>         PyTuple_SET_ITEM (anddata, loop, PyInt_FromLong (cursor->mask[loop]));
>>>>     }
>>>> -
>>>> -    return Py_BuildValue ("((ii)(ii)OO)", w, h, spotx, spoty,
>>>> xordata, anddata);
>>>> +       ret = Py_BuildValue ("((ii)(ii)OO)", w, h, spotx, spoty, xordata, anddata);
>>>> +       Py_DECREF (xordata);
>>>> +       Py_DECREF (anddata);
>>>> +    return ret;
>>>>  }
>>>>
>>>>  static PyMethodDef mouse_builtins[] =
>>>>
>>>
>>
>