From: Emiel Bruijntjes <emiel.bruijntjes@copernica.com>
Date: Fri, 27 Nov 2015 15:49:32 +0000 (+0100)
Subject: reference increment and decrement is now atomic (when using a GCC compatible compiler... 
X-Git-Tag: json-c-0.13-20171207~59^2~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=23ee243113ac47730c7ca900b35a1abbcb568743;p=thirdparty%2Fjson-c.git

reference increment and decrement is now atomic (when using a GCC compatible compiler), which allows passing json objects between threads
---

diff --git a/json_object.c b/json_object.c
index 9ac22a30..cad31374 100644
--- a/json_object.c
+++ b/json_object.c
@@ -160,25 +160,29 @@ static int json_escape_str(struct printbuf *pb, const char *str, int len)
 
 extern struct json_object* json_object_get(struct json_object *jso)
 {
-	if (jso)
-		jso->_ref_count++;
+	if (!jso) return jso;
+#if defined __GNUC__
+    __sync_add_and_fetch(&jso->_ref_count, 1);
+#else
+    ++jso->_ref_count;
+#endif        
 	return jso;
 }
 
 int json_object_put(struct json_object *jso)
 {
-	if(jso)
-	{
-		jso->_ref_count--;
-		if(!jso->_ref_count)
-		{
-			if (jso->_user_delete)
-				jso->_user_delete(jso, jso->_userdata);
-			jso->_delete(jso);
-			return 1;
-		}
-	}
-	return 0;
+	if(!jso) return 0;
+
+#if defined __GNUC__
+    if (__sync_fetch_and_sub(&jso->_ref_count, 1) > 0) return 0;
+#else
+    if (--jso->_ref_count > 0) return 0;
+#endif
+
+    if (jso->_user_delete)
+        jso->_user_delete(jso, jso->_userdata);
+    jso->_delete(jso);
+    return 1;
 }