helper/log: Add log_vprintf_lf()

Add log_vprintf_lf() to enable the possibility to output log messages
with a variable argument list.

Change-Id: I7fd6e93db63a7d98f662df2881a42e4d923c3848
Signed-off-by: Marc Schink <openocd-dev@marcschink.de>
Reviewed-on: http://openocd.zylin.com/3709
Tested-by: jenkins
Reviewed-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

src/helper/log.c

@@ -191,6 +191,30 @@ void log_printf(enum log_levels level,
 	va_end(ap);
 }
 
+void log_vprintf_lf(enum log_levels level, const char *file, unsigned line,
+		const char *function, const char *format, va_list args)
+{
+	char *tmp;
+
+	count++;
+
+	if (level > debug_level)
+		return;
+
+	tmp = alloc_vprintf(format, args);
+
+	if (!tmp)
+		return;
+
+	/*
+	 * Note: alloc_vprintf() guarantees that the buffer is at least one
+	 * character longer.
+	 */
+	strcat(tmp, "\n");
+	log_puts(level, file, line, function, tmp);
+	free(tmp);
+}
+
 void log_printf_lf(enum log_levels level,
 	const char *file,
 	unsigned line,
@@ -198,23 +222,10 @@ void log_printf_lf(enum log_levels level,
 	const char *format,
 	...)
 {
-	char *string;
 	va_list ap;
 
-	count++;
-	if (level > debug_level)
-		return;
-
 	va_start(ap, format);
-
+	log_vprintf_lf(level, file, line, function, format, ap);
-	string = alloc_vprintf(format, ap);
-	if (string != NULL) {
-		strcat(string, "\n");	/* alloc_vprintf guaranteed the buffer to be at least one
-					 *char longer */
-		log_puts(level, file, line, function, string);
-		free(string);
-	}
-
 	va_end(ap);
 }
 

src/helper/log.h

@@ -60,6 +60,8 @@ enum log_levels {
 void log_printf(enum log_levels level, const char *file, unsigned line,
 		const char *function, const char *format, ...)
 __attribute__ ((format (PRINTF_ATTRIBUTE_FORMAT, 5, 6)));
+void log_vprintf_lf(enum log_levels level, const char *file, unsigned line,
+		const char *function, const char *format, va_list args);
 void log_printf_lf(enum log_levels level, const char *file, unsigned line,
 		const char *function, const char *format, ...)
 __attribute__ ((format (PRINTF_ATTRIBUTE_FORMAT, 5, 6)));