From 3fb3d8db3d566f231ea6ff6afd559a0185d8bff7 Mon Sep 17 00:00:00 2001
From: mathieui <mathieui@mathieui.net>
Date: Sun, 27 Apr 2014 21:33:00 +0200
Subject: [PATCH] Fix memleaks in pooptmodule.cut_text (ref #1914)
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- we need to decrement the refcount after giving the tuple to the
  retlist in order to transfer ownership

The example script below will quickly take gigabytes of ram with the
old module, while the new will not take noticeably more memory.

The leak is not very visible on launch, because we “only” leaked each
tuple returned, and (int, int) is not heavy. However, after weeks of
use and many messages, the memory still isn’t freed and it shows.

import poopt
import gc

a = 'coucouco ' * 1000
for i in range(100000):
    if not (i % 10000):
        print(i)
    poopt.cut_text(a, 50)
---
 src/pooptmodule.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/src/pooptmodule.c b/src/pooptmodule.c
index 4dab1088..69fb7f6f 100644
--- a/src/pooptmodule.c
+++ b/src/pooptmodule.c
@@ -63,6 +63,8 @@ static PyObject* poopt_cut_text(PyObject* self, PyObject* args)
 {
     /* The list of tuples that we return */
     PyObject* retlist = PyList_New(0);
+    /* The temporary name for the tuples */
+    PyObject* tmp;
 
     /* Get the python arguments */
     const size_t width;
@@ -146,8 +148,13 @@ static PyObject* poopt_cut_text(PyObject* self, PyObject* args)
         if (wc == (wchar_t)'\n')
         {
             spos++;
-            if (PyList_Append(retlist, Py_BuildValue("II", start_pos, spos)) == -1)
+            tmp = Py_BuildValue("II", start_pos, spos);
+            if (PyList_Append(retlist, tmp) == -1)
+            {
+                Py_XDECREF(tmp);
                 return NULL;
+            }
+            Py_XDECREF(tmp);
             /* And then initiate a new line */
             start_pos = spos;
             last_space = -1;
@@ -164,8 +171,13 @@ static PyObject* poopt_cut_text(PyObject* self, PyObject* args)
         {   /* If possible, cut on a space */
             if (last_space != -1)
             {
-                if (PyList_Append(retlist, Py_BuildValue("II", start_pos, last_space)) == -1)
+                tmp = Py_BuildValue("II", start_pos, last_space);
+                if (PyList_Append(retlist, tmp) == -1)
+                {
+                    Py_XDECREF(tmp);
                     return NULL;
+                }
+                Py_XDECREF(tmp);
                 start_pos = last_space + 1;
                 last_space = -1;
                 columns -= (cols_until_space + 1);
@@ -173,8 +185,13 @@ static PyObject* poopt_cut_text(PyObject* self, PyObject* args)
             else
             {
                 /* Otherwise, cut in the middle of a word */
-                if (PyList_Append(retlist, Py_BuildValue("II", start_pos, spos)) == -1)
+                tmp = Py_BuildValue("II", start_pos, spos);
+                if (PyList_Append(retlist, tmp) == -1)
+                {
+                    Py_XDECREF(tmp);
                     return NULL;
+                }
+                Py_XDECREF(tmp);
                 start_pos = spos;
                 columns = 0;
             }
@@ -194,8 +211,13 @@ static PyObject* poopt_cut_text(PyObject* self, PyObject* args)
         spos++;
     }
     /* We are at the end of the string, append the last line, not finished */
-    if (PyList_Append(retlist, Py_BuildValue("II", start_pos, spos)) == -1)
+    tmp = Py_BuildValue("II", start_pos, spos);
+    if (PyList_Append(retlist, tmp) == -1)
+    {
+        Py_XDECREF(tmp);
         return NULL;
+    }
+    Py_XDECREF(tmp);
     return retlist;
 }