Re: [pygame] memory leaks with Py_BuildValue

["Campbell Barton" <ideasman42@xxxxxxxxx>]

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[] =
>>
>