TimePoint::Now uses DartTimestampProvider #27737
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fml/time/dart_timestamp_provider.cc
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| DartTimestampProvider::~DartTimestampProvider() = default; | ||
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| fml::TimePoint DartTimestampProvider::Now() { | ||
| return fml::TimePoint::FromTicks(Dart_TimelineGetTicks()); |
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Perhaps I don't understand this API but this seems off to me. Here, we are depending on the timebases of fml::TimePoint and Dart_Timeline to be identical. Looking at what was recently exposed we'd need to take into the timebase using Dart_TimelineGetTicksFrequency. Maybe we are getting away with these because both are in nanoseconds?
| TEST(TimePoint, DartClockIsMonotonic) { | ||
| using namespace std::chrono_literals; | ||
| const auto t1 = DartTimelineTicksSinceEpoch(); | ||
| std::this_thread::sleep_for(1us); |
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@chinmaygarde that was a good catch, I am now converting from frequency base to nano seconds. But looks like on windows the frequency can be less than once per nano second (based on the test failure on windows bots), so I've added this sleep for 1us. Is it reasonable?
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also the resolution seems to be < 1us (on windows), so had to change to ASSERT_LE rather than ASSERT_LT :-/ but it was always the case (not a regression)
Fixes flutter/flutter#76875