From fd56f7e646cfc065e8d72e93d1a40e67e1ae62f0 Mon Sep 17 00:00:00 2001
From: Kefu Chai <kchai@redhat.com>
Date: Wed, 13 Jan 2021 13:58:48 +0800
Subject: [PATCH] common/ceph_time: print {milli,nano}seconds as float

this change fixes the regression introduced by
6e1d42ca004ae191c445dac41606142c376124b1

add unit test for verifying 'operator<<' as well.

Signed-off-by: Kefu Chai <kchai@redhat.com>
---
 src/common/ceph_time.cc      |  3 ++-
 src/test/common/test_time.cc | 40 ++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/common/ceph_time.cc b/src/common/ceph_time.cc
index 603165efb43c5..69b3cdde6e87d 100644
--- a/src/common/ceph_time.cc
+++ b/src/common/ceph_time.cc
@@ -324,7 +324,8 @@ std::chrono::seconds parse_timespan(const std::string& s)
 namespace std {
 template<typename Rep, typename Period>
 ostream& operator<<(ostream& m, const chrono::duration<Rep, Period>& t) {
-  if constexpr (chrono::treat_as_floating_point_v<Rep>) {
+  if constexpr (chrono::treat_as_floating_point_v<Rep> ||
+                Period::den > 1) {
     using seconds_t = chrono::duration<float>;
     ::fmt::print(m, "{:.9}", chrono::duration_cast<seconds_t>(t));
   } else {
diff --git a/src/test/common/test_time.cc b/src/test/common/test_time.cc
index 347916114bf39..3054aa50ef7ac 100644
--- a/src/test/common/test_time.cc
+++ b/src/test/common/test_time.cc
@@ -192,3 +192,43 @@ TEST(TimePoints, stringify) {
   ASSERT_TRUE(s[26] == '-' || s[26] == '+');
   ASSERT_EQ(s.substr(0, 9), "2019-04-2");
 }
+
+namespace {
+  template<typename Rep, typename Period>
+  std::string to_string(const chrono::duration<Rep, Period>& t)
+  {
+    std::ostringstream ss;
+    ss << t;
+    return ss.str();
+  }
+
+  void float_format_eq(string_view lhs,
+                       string_view rhs,
+                       unsigned precision)
+  {
+    const float TOLERANCE = 10.0F / pow(10.0F, static_cast<float>(precision));
+    ASSERT_FALSE(lhs.empty());
+    ASSERT_EQ(lhs.back(), 's');
+    float lhs_v = std::stof(string{lhs, 0, lhs.find('s')});
+    ASSERT_NE(lhs.npos, lhs.find('.'));
+    ASSERT_EQ(precision, lhs.find('s') - lhs.find('.') - 1);
+
+    ASSERT_FALSE(rhs.empty());
+    ASSERT_EQ(rhs.back(), 's');
+    float rhs_v = std::stof(string{rhs, 0, rhs.find('s')});
+    EXPECT_NEAR(lhs_v, rhs_v, TOLERANCE);
+    ASSERT_NE(rhs.npos, rhs.find('.'));
+    EXPECT_EQ(precision, rhs.find('s') - rhs.find('.') - 1);
+  }
+}
+
+TEST(TimeDurations, print) {
+  float_format_eq("0.123456700s",
+                  to_string(std::chrono::duration_cast<ceph::timespan>(0.1234567s)),
+                  9);
+  float_format_eq("-0.123456700s",
+                  to_string(std::chrono::duration_cast<ceph::signedspan>(-0.1234567s)),
+                  9);
+  EXPECT_EQ("42s", to_string(42s));
+  float_format_eq("0.123000000s", to_string(123ms), 9);
+}
-- 
2.39.5