Program Listing for File timestamp.h
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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include <algorithm>
#include <chrono>
#include <cstdint>
#include "opentelemetry/version.h"
OPENTELEMETRY_BEGIN_NAMESPACE
namespace common
{
class SystemTimestamp
{
public:
SystemTimestamp() noexcept : nanos_since_epoch_{0} {}
template <class Rep, class Period>
explicit SystemTimestamp(const std::chrono::duration<Rep, Period> &time_since_epoch) noexcept
: nanos_since_epoch_{static_cast<int64_t>(
std::chrono::duration_cast<std::chrono::nanoseconds>(time_since_epoch).count())}
{}
/*implicit*/ SystemTimestamp(const std::chrono::system_clock::time_point &time_point) noexcept
: SystemTimestamp{time_point.time_since_epoch()}
{}
operator std::chrono::system_clock::time_point() const noexcept
{
return std::chrono::system_clock::time_point{
std::chrono::duration_cast<std::chrono::system_clock::duration>(
std::chrono::nanoseconds{nanos_since_epoch_})};
}
std::chrono::nanoseconds time_since_epoch() const noexcept
{
return std::chrono::nanoseconds{nanos_since_epoch_};
}
bool operator==(const SystemTimestamp &other) const noexcept
{
return nanos_since_epoch_ == other.nanos_since_epoch_;
}
bool operator!=(const SystemTimestamp &other) const noexcept
{
return nanos_since_epoch_ != other.nanos_since_epoch_;
}
private:
int64_t nanos_since_epoch_;
};
class SteadyTimestamp
{
public:
SteadyTimestamp() noexcept : nanos_since_epoch_{0} {}
template <class Rep, class Period>
explicit SteadyTimestamp(const std::chrono::duration<Rep, Period> &time_since_epoch) noexcept
: nanos_since_epoch_{static_cast<int64_t>(
std::chrono::duration_cast<std::chrono::nanoseconds>(time_since_epoch).count())}
{}
/*implicit*/ SteadyTimestamp(const std::chrono::steady_clock::time_point &time_point) noexcept
: SteadyTimestamp{time_point.time_since_epoch()}
{}
operator std::chrono::steady_clock::time_point() const noexcept
{
return std::chrono::steady_clock::time_point{
std::chrono::duration_cast<std::chrono::steady_clock::duration>(
std::chrono::nanoseconds{nanos_since_epoch_})};
}
std::chrono::nanoseconds time_since_epoch() const noexcept
{
return std::chrono::nanoseconds{nanos_since_epoch_};
}
bool operator==(const SteadyTimestamp &other) const noexcept
{
return nanos_since_epoch_ == other.nanos_since_epoch_;
}
bool operator!=(const SteadyTimestamp &other) const noexcept
{
return nanos_since_epoch_ != other.nanos_since_epoch_;
}
private:
int64_t nanos_since_epoch_;
};
class DurationUtil
{
public:
template <class Rep, class Period>
static std::chrono::duration<Rep, Period> AdjustWaitForTimeout(
std::chrono::duration<Rep, Period> timeout,
std::chrono::duration<Rep, Period> indefinite_value) noexcept
{
// Do not call now() when this duration is max value, now() may have a expensive cost.
if (timeout == std::chrono::duration<Rep, Period>::max())
{
return indefinite_value;
}
// std::future<T>::wait_for, std::this_thread::sleep_for, and std::condition_variable::wait_for
// may use steady_clock or system_clock.We need make sure now() + timeout do not overflow.
auto max_timeout = std::chrono::duration_cast<std::chrono::duration<Rep, Period>>(
std::chrono::steady_clock::time_point::max() - std::chrono::steady_clock::now());
if (timeout >= max_timeout)
{
return indefinite_value;
}
max_timeout = std::chrono::duration_cast<std::chrono::duration<Rep, Period>>(
std::chrono::system_clock::time_point::max() - std::chrono::system_clock::now());
if (timeout >= max_timeout)
{
return indefinite_value;
}
return timeout;
}
};
} // namespace common
OPENTELEMETRY_END_NAMESPACE