From e56263b057fbf8ceb542c8120c620865c3c48c1e Mon Sep 17 00:00:00 2001
From: Kefu Chai <kchai@redhat.com>
Date: Tue, 18 May 2021 01:13:03 +0800
Subject: [PATCH] crimson/os: use compile-time validation

libfmt does compile-time format argument validation of the format string
and the argument when the the user-defined literal is used. but the
downside is that the formatter materialize the whole formatted string
into a std::string, before printing them argument into seastar's log buffer
inserter. presumably, the inserter would be more efficient in
comparision to the pre-format approach. so this validation is only
enabled for non NDEBUG build. so it is able to help us to identify
errors like

DEBUG("{} {}", 1, 2, 3)

Signed-off-by: Kefu Chai <kchai@redhat.com>
---
 src/crimson/os/seastore/logging.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/src/crimson/os/seastore/logging.h b/src/crimson/os/seastore/logging.h
index 9efe5b0e17a60..030094b6c68e3 100644
--- a/src/crimson/os/seastore/logging.h
+++ b/src/crimson/os/seastore/logging.h
@@ -3,11 +3,15 @@
 
 #pragma once
 
+#include <fmt/format.h>
+
 #include "crimson/common/log.h"
 
 #define LOGGER crimson::get_logger(ceph_subsys_seastore)
 #define LOG_PREFIX(x) constexpr auto FNAME = #x
 
+#ifdef NDEBUG
+
 #define LOG(LEVEL, MSG, ...) LOGGER . LEVEL("{}: " MSG, FNAME __VA_OPT__(,) __VA_ARGS__)
 #define LOGT(LEVEL, MSG, t, ...) LOGGER . LEVEL("{}({}): " MSG, FNAME, (void*)&t __VA_OPT__(,) __VA_ARGS__)
 
@@ -25,3 +29,26 @@
 
 #define ERROR(...) LOG(error, __VA_ARGS__)
 #define ERRORT(...) LOGT(error, __VA_ARGS__)
+
+#else
+// do compile-time format string validation
+using namespace fmt::literals;
+template<seastar::log_level lv>
+void LOG(std::string_view info) {
+  crimson::get_logger(ceph_subsys_seastore).log(lv, info);
+}
+#define TRACE(MSG_, ...) LOG<seastar::log_level::trace>("{}: " MSG_ ## _format(FNAME __VA_OPT__(,) __VA_ARGS__))
+#define TRACET(MSG_, t_, ...) LOG<seastar::log_level::trace>("{}({}): " MSG_ ## _format(FNAME, (void*)&t_ __VA_OPT__(,) __VA_ARGS__))
+
+#define DEBUG(MSG_, ...) LOG<seastar::log_level::debug>("{}: " MSG_ ## _format(FNAME __VA_OPT__(,) __VA_ARGS__))
+#define DEBUGT(MSG_, t_, ...) LOG<seastar::log_level::debug>("{}({}): " MSG_ ## _format(FNAME, (void*)&t_ __VA_OPT__(,) __VA_ARGS__))
+
+#define INFO(MSG_, ...) LOG<seastar::log_level::info>("{}: " MSG_ ## _format(FNAME __VA_OPT__(,) __VA_ARGS__))
+#define INFOT(MSG_, t_, ...) LOG<seastar::log_level::info>("{}({}): " MSG_ ## _format(FNAME, (void*)&t_ __VA_OPT__(,) __VA_ARGS__))
+
+#define WARN(MSG_, ...) LOG<seastar::log_level::warn>("{}: " MSG_ ## _format(FNAME __VA_OPT__(,) __VA_ARGS__))
+#define WARNT(MSG_, t_, ...) LOG<seastar::log_level::warn>("{}({}): " MSG_ ## _format(FNAME, (void*)&t_ __VA_OPT__(,) __VA_ARGS__))
+
+#define ERROR(MSG_, ...) LOG<seastar::log_level::error>("{}: " MSG_ ## _format(FNAME __VA_OPT__(,) __VA_ARGS__))
+#define ERRORT(MSG_, t_, ...) LOG<seastar::log_level::error>("{}({}): " MSG_ ## _format(FNAME, (void*)&t_ __VA_OPT__(,) __VA_ARGS__))
+#endif
-- 
2.39.5