Fix DurationToMilliseconds mult overflow

PiperOrigin-RevId: 588443477

src/google/protobuf/util/time_util.cc

@@ -311,11 +311,13 @@ int64_t TimeUtil::DurationToNanoseconds(const Duration& duration) {
 }
 
 int64_t TimeUtil::DurationToMicroseconds(const Duration& duration) {
-  return RoundTowardZero(DurationToNanoseconds(duration), kNanosPerMicrosecond);
+  return DurationToSeconds(duration) * kMicrosPerSecond +
+         RoundTowardZero(duration.nanos(), kNanosPerMicrosecond);
 }
 
 int64_t TimeUtil::DurationToMilliseconds(const Duration& duration) {
-  return RoundTowardZero(DurationToNanoseconds(duration), kNanosPerMillisecond);
+  return DurationToSeconds(duration) * kMillisPerSecond +
+         RoundTowardZero(duration.nanos(), kNanosPerMillisecond);
 }
 
 int64_t TimeUtil::DurationToSeconds(const Duration& duration) {

src/google/protobuf/util/time_util_test.cc

@@ -145,6 +145,12 @@ TEST(TimeUtilTest, DurationIntegerConversion) {
       1, TimeUtil::DurationToMilliseconds(TimeUtil::MillisecondsToDuration(1)));
   EXPECT_EQ(-1, TimeUtil::DurationToMilliseconds(
                     TimeUtil::MillisecondsToDuration(-1)));
+  // Test overflow issue
+  EXPECT_EQ(315576000000000, TimeUtil::DurationToMilliseconds(
+                                 TimeUtil::SecondsToDuration(315576000000)));
+  // Test overflow issue
+  EXPECT_EQ(315576000000000000, TimeUtil::DurationToMicroseconds(
+                                    TimeUtil::SecondsToDuration(315576000000)));
   EXPECT_EQ(1, TimeUtil::DurationToSeconds(TimeUtil::SecondsToDuration(1)));
   EXPECT_EQ(-1, TimeUtil::DurationToSeconds(TimeUtil::SecondsToDuration(-1)));
   EXPECT_EQ(1, TimeUtil::DurationToMinutes(TimeUtil::MinutesToDuration(1)));