Add vlog functions and macros for testing whether a module and level are enabled.

diff --git a/include/vlog.h b/include/vlog.h
index 63a0c412e1fe5f6db6522b47a6a9d5caa0e5526e..7d15ad284c0517328f8188e03fd03c66147a502f 100644 (file)
--- a/include/vlog.h
+++ b/include/vlog.h
@@ -98,6 +98,7 @@ enum vlog_level vlog_get_level(enum vlog_module, enum vlog_facility);
 void vlog_set_levels(enum vlog_module, enum vlog_facility, enum vlog_level);
 char *vlog_set_levels_from_string(const char *);
 char *vlog_get_levels(void);
+bool vlog_is_enabled(enum vlog_module, enum vlog_level);
 void vlog_set_verbosity(const char *arg);
 
 /* Function for actual logging. */
@@ -117,4 +118,12 @@ void vlog(enum vlog_module, enum vlog_level, const char *format, ...)
 #define VLOG_WARN(...) vlog(THIS_MODULE, VLL_WARN, __VA_ARGS__)
 #define VLOG_DBG(...) vlog(THIS_MODULE, VLL_DBG, __VA_ARGS__)
 
+/* More convenience macros, for testing whether a given level is enabled in
+ * THIS_MODULE.  When constructing a log message is expensive, this enables it
+ * to be skipped. */
+#define VLOG_IS_EMER_ENABLED() true
+#define VLOG_IS_ERR_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_EMER)
+#define VLOG_IS_WARN_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_WARN)
+#define VLOG_IS_DBG_ENABLED() vlog_is_enabled(THIS_MODULE, VLL_DBG)
+
 #endif /* vlog.h */

diff --git a/lib/vlog.c b/lib/vlog.c
index 3c977bf6504fd7d72b8cdebff9acf96896d88c1d..631627234fcf3b5752aa68feb20382570abf8053 100644 (file)
--- a/lib/vlog.c
+++ b/lib/vlog.c
@@ -277,6 +277,16 @@ vlog_get_levels(void)
     return ds_cstr(&s);
 }
 
+/* Returns true if a log message emitted for the given 'module' and 'level'
+ * would cause some log output, false if that module and level are completely
+ * disabled. */
+bool
+vlog_is_enabled(enum vlog_module module, enum vlog_level level)
+{
+    return (levels[module][VLF_CONSOLE] >= level
+            || levels[module][VLF_SYSLOG] >= level);
+}
+
 /* Writes 'message' to the log at the given 'level' and as coming from the
  * given 'module'.
  *