Add debugging macros

Similarly to what GTK+ and Clutter do, we can use macros that evaluate
to nothing if JSON_ENABLE_DEBUG is disabled; they evaluate to messages
when the JSON_DEBUG environment variable is set to a debug domain.

1 files changed, 45 insertions, 0 deletions

diff --git a/json-glib/json-debug.h b/json-glib/json-debug.h
new file mode 100644
index 0000000..dc0d861
--- /dev/null
+++ b/json-glib/json-debug.h
@@ -0,0 +1,45 @@
+#ifndef __JSON_DEBUG_H__
+#define __JSON_DEBUG_H__
+
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+typedef enum {
+  JSON_DEBUG_PARSER = 1 << 0
+} JsonDebugFlags;
+
+#ifdef JSON_ENABLE_DEBUG
+
+# ifdef __GNUC__
+
+# define JSON_NOTE(type,x,a...)                 G_STMT_START {  \
+        if (_json_get_debug_flags () & JSON_DEBUG_##type) {     \
+          g_message ("[" #type "] " G_STRLOC ": " x, ##a);      \
+        }                                       } G_STMT_END
+
+# else
+/* Try the C99 version; unfortunately, this does not allow us to pass
+ * empty arguments to the macro, which means we have to
+ * do an intemediate printf.
+ */
+# define JSON_NOTE(type,...)                    G_STMT_START {  \
+        if (_json_get_debug_flags () & JSON_DEBUG_##type) {     \
+            gchar * _fmt = g_strdup_printf (__VA_ARGS__);       \
+            g_message ("[" #type "] " G_STRLOC ": %s",_fmt);    \
+            g_free (_fmt);                                      \
+        }                                       } G_STMT_END
+
+# endif /* __GNUC__ */
+
+#else
+
+#define JSON_NOTE(type,...)         G_STMT_START { } G_STMT_END
+
+#endif /* JSON_ENABLE_DEBUG */
+
+JsonDebugFlags _json_get_debug_flags (void);
+
+G_END_DECLS
+
+#endif /* __JSON_DEBUG_H__ */