From 9586d2794a35d6057701025331b0e06eea529e13 Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Thu, 14 Jun 2018 11:32:56 +0200
Subject: [PATCH] shared: simplify nm_g_object_ref_set()

Also, assign *_pp before unref-ing the old value. Calling
g_object_unref() on the old value, might invoke callbacks
that are out of control of nm_g_object_ref_set(). During
that time, the pointer should already be assigned the new value,
instead of having an intermediate %NULL value. In most cases,
this would of course not matter, but there is no need to let
anyone see an intermediate %NULL value for a moment.

Also, don't use typeof(**_pp), which would not work with opaque
types (like we commonly have).
---
 shared/nm-utils/nm-macros-internal.h | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/shared/nm-utils/nm-macros-internal.h b/shared/nm-utils/nm-macros-internal.h
index 908b25fdbe..ef3039e642 100644
--- a/shared/nm-utils/nm-macros-internal.h
+++ b/shared/nm-utils/nm-macros-internal.h
@@ -807,8 +807,8 @@ nm_g_object_unref (gpointer obj)
 		g_object_unref (obj);
 }
 
-/* Assigns GObject @obj to destination @pdst, and takes an additional ref.
- * The previous value of @pdst is unrefed.
+/* Assigns GObject @obj to destination @pp, and takes an additional ref.
+ * The previous value of @pp is unrefed.
  *
  * It makes sure to first increase the ref-count of @obj, and handles %NULL
  * @obj correctly.
@@ -816,22 +816,18 @@ nm_g_object_unref (gpointer obj)
 #define nm_g_object_ref_set(pp, obj) \
 	({ \
 		typeof (*(pp)) *const _pp = (pp); \
-		typeof (**_pp) *const _obj = (obj); \
-		typeof (**_pp) *_p; \
+		typeof (*_pp) const _obj = (obj); \
+		typeof (*_pp) _p; \
 		gboolean _changed = FALSE; \
 		\
+		nm_assert (!_pp || !*_pp || G_IS_OBJECT (*_pp)); \
+		nm_assert (!_obj || G_IS_OBJECT (_obj)); \
+		\
 		if (   _pp \
 		    && ((_p = *_pp) != _obj)) { \
-			if (_obj) { \
-				nm_assert (G_IS_OBJECT (_obj)); \
-				 g_object_ref (_obj); \
-			} \
-			if (_p) { \
-				nm_assert (G_IS_OBJECT (_p)); \
-				*_pp = NULL; \
-				g_object_unref (_p); \
-			} \
+			nm_g_object_ref (_obj); \
 			*_pp = _obj; \
+			nm_g_object_unref (_p); \
 			_changed = TRUE; \
 		} \
 		_changed; \