From: Sven Trenkel <collectd@semidefinite.de>
Date: Tue, 22 Dec 2009 01:20:42 +0000 (+0100)
Subject: Added macro CPY_SUBSTITUTE.
X-Git-Tag: collectd-4.10.0~76^2~8
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=50b21162a21571facd6bbd8a8f9e694dbd7d02e1;p=collectd.git

Added macro CPY_SUBSTITUTE.
---

diff --git a/src/cpython.h b/src/cpython.h
index 001a3ae9..10a1a54c 100644
--- a/src/cpython.h
+++ b/src/cpython.h
@@ -74,6 +74,20 @@
 # define Py_RETURN_NONE return Py_INCREF(Py_None), Py_None
 #endif
 
+/* This macro is a shortcut for calls like
+ * x = PyObject_Repr(x);
+ * This can't be done like this example because this would leak
+ * a reference the the original x and crash in case of x == NULL.
+ * This calling syntax is less than elegant but it works, saves
+ * a lot of lines and avoids potential refcount errors. */
+
+#define CPY_SUBSTITUTE(func, a, ...) do {\
+	if ((a) != NULL) {\
+		PyObject *tmp = (a);\
+		(a) = func(__VA_ARGS__);\
+		Py_DECREF(tmp);\
+	}\
+} while(0)
 
 /* Python3 compatibility layer. To keep the actual code as clean as possible
  * do a lot of defines here. */
diff --git a/src/pyconfig.c b/src/pyconfig.c
index d794c9a8..53e80e43 100644
--- a/src/pyconfig.c
+++ b/src/pyconfig.c
@@ -120,7 +120,7 @@ static int Config_init(PyObject *s, PyObject *args, PyObject *kwds) {
 
 static PyObject *Config_repr(PyObject *s) {
 	Config *self = (Config *) s;
-	PyObject *name, *tmp, *ret = NULL;
+	PyObject *ret = NULL;
 	static PyObject *node_prefix = NULL, *root_prefix = NULL, *ending = NULL;
 	
 	/* This is ok because we have the GIL, so this is thread-save by default. */
@@ -133,19 +133,12 @@ static PyObject *Config_repr(PyObject *s) {
 	if (node_prefix == NULL || root_prefix == NULL || ending == NULL)
 		return NULL;
 	
-	name = PyObject_Str(self->key);
-	if (name == NULL)
-		return NULL;
-
+	ret = PyObject_Str(self->key);
 	if (self->parent == NULL || self->parent == Py_None)
-		tmp = CPY_STRCAT(root_prefix, name);
+		CPY_SUBSTITUTE(CPY_STRCAT, ret, root_prefix, ret);
 	else
-		tmp = CPY_STRCAT(node_prefix, name);
-	
-	Py_DECREF(name);
-	if (tmp != NULL)
-		ret = CPY_STRCAT(tmp, ending);
-	Py_DECREF(tmp);
+		CPY_SUBSTITUTE(CPY_STRCAT, ret, node_prefix, ret);
+	CPY_SUBSTITUTE(CPY_STRCAT, ret, ret, ending);
 	
 	return ret;
 }