fix imaging leaks in putdata and getlist

Tests/check_imaging_leaks.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python
+
+from __future__ import division
+from helper import unittest, PillowTestCase
+import sys
+from PIL import Image, ImageFilter
+
+min_iterations = 100
+max_iterations = 10000
+
+@unittest.skipIf(sys.platform.startswith('win32'), "requires Unix or MacOS")
+class TestImagingLeaks(PillowTestCase):
+
+    def _get_mem_usage(self):
+        from resource import getpagesize, getrusage, RUSAGE_SELF
+        mem = getrusage(RUSAGE_SELF).ru_maxrss
+        return mem * getpagesize() / 1024 / 1024
+
+    def _test_leak(self, min_iterations, max_iterations, fn, *args, **kwargs):
+        mem_limit = None
+        for i in range(max_iterations):
+            fn(*args, **kwargs)
+            mem = self._get_mem_usage()
+            if i < min_iterations:
+                mem_limit = mem + 1
+                continue
+            self.assertLessEqual(mem, mem_limit,
+                                 msg='memory usage limit exceeded after %d iterations'
+                                 % (i + 1))
+
+    def test_leak_putdata(self):
+        im = Image.new('RGB', (25, 25))
+        self._test_leak(min_iterations, max_iterations, im.putdata, im.getdata())
+
+    def test_leak_getlist(self):
+        im = Image.new('P', (25, 25))
+        self._test_leak(min_iterations, max_iterations,
+                        # Pass a new list at each iteration.
+                        lambda: im.point(range(256)))
+
+if __name__ == '__main__':
+    unittest.main()
+

_imaging.c

@@ -421,6 +421,7 @@ getlist(PyObject* arg, int* length, const char* wrong_length, int type)
         *length = n;
 
     PyErr_Clear();
+    Py_DECREF(seq);
 
     return list;
 }
@@ -1221,7 +1222,7 @@ _putdata(ImagingObject* self, PyObject* args)
     Py_ssize_t n, i, x, y;
 
     PyObject* data;
-    PyObject* seq;
+    PyObject* seq = NULL;
     PyObject* op;
     double scale = 1.0;
     double offset = 0.0;
@@ -1329,6 +1330,7 @@ _putdata(ImagingObject* self, PyObject* args)
 
                 op = PySequence_Fast_GET_ITEM(seq, i);
                 if (!op || !getink(op, image, u.ink)) {
+                    Py_DECREF(seq);
                     return NULL;
                 }
                 /* FIXME: what about scale and offset? */
@@ -1342,6 +1344,8 @@ _putdata(ImagingObject* self, PyObject* args)
         }
     }
 
+    Py_XDECREF(seq);
+
     Py_INCREF(Py_None);
     return Py_None;
 }