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#include "monotonic.h"
#include <chrono>
#include <optional>
#include <system_error>
#include <util/system/platform.h>
#ifdef _linux_
#include <time.h>
#include <string.h>
#endif
namespace NMonotonic {
namespace {
#if defined(_linux_) && defined(CLOCK_BOOTTIME)
std::optional<ui64> GetClockBootTimeMicroSeconds() {
struct timespec t;
std::optional<ui64> r;
if (0 == ::clock_gettime(CLOCK_BOOTTIME, &t)) {
r.emplace(t.tv_nsec / 1000ULL + t.tv_sec * 1000000ULL);
}
return r;
}
#endif
struct TMonotonicSupport {
#if defined(_linux_) && defined(CLOCK_BOOTTIME)
// We remember initial offset to measure time relative to program
// start and so we never return a zero time.
std::optional<ui64> BootTimeOffset;
#endif
// Unfortunately time_since_epoch() is sometimes negative on wine
// Remember initial time point at program start and use offsets from that
std::chrono::steady_clock::time_point SteadyClockOffset;
TMonotonicSupport() {
#if defined(_linux_) && defined(CLOCK_BOOTTIME)
BootTimeOffset = GetClockBootTimeMicroSeconds();
#endif
SteadyClockOffset = std::chrono::steady_clock::now();
}
ui64 GetMicroSeconds() const {
#if defined(_linux_) && defined(CLOCK_BOOTTIME)
if (Y_LIKELY(BootTimeOffset)) {
auto r = GetClockBootTimeMicroSeconds();
if (Y_UNLIKELY(!r)) {
throw std::system_error(
std::error_code(errno, std::system_category()),
"clock_gettime(CLOCK_BOOTTIME) failed");
}
// Note: we add 1 so we never return zero
return *r - *BootTimeOffset + 1;
}
#endif
auto elapsed = std::chrono::steady_clock::now() - SteadyClockOffset;
auto microseconds = std::chrono::duration_cast<std::chrono::microseconds>(elapsed).count();
// Steady clock is supposed to never jump backwards, but it's
// better to be safe in case of buggy implementations
if (Y_UNLIKELY(microseconds < 0)) {
microseconds = 0;
}
// Note: we add 1 so we never return zero
return ui64(microseconds) + 1;
}
};
TMonotonicSupport MonotonicSupport;
}
ui64 GetMonotonicMicroSeconds() {
return MonotonicSupport.GetMicroSeconds();
}
}
template <>
void Out<NMonotonic::TMonotonic>(
IOutputStream& o,
NMonotonic::TMonotonic t)
{
o << t - NMonotonic::TMonotonic::Zero();
}
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