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/*
* Copyright (C) 2016-2019 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <wtf/ClockType.h>
#include <wtf/GenericTimeMixin.h>
namespace WTF {
class WallTime;
class PrintStream;
// The current time according to a monotonic clock. Monotonic clocks don't go backwards and
// possibly don't count downtime. This uses floating point internally so that you can reason about
// infinity and other things that arise in math. It's acceptable to use this to wrap NaN times,
// negative times, and infinite times, so long as they are all relative to the same clock.
class MonotonicTime final : public GenericTimeMixin<MonotonicTime> {
public:
static constexpr ClockType clockType = ClockType::Monotonic;
// This is the epoch. So, x.secondsSinceEpoch() should be the same as x - MonotonicTime().
constexpr MonotonicTime() = default;
#if OS(DARWIN)
WTF_EXPORT_PRIVATE static MonotonicTime fromMachAbsoluteTime(uint64_t);
WTF_EXPORT_PRIVATE uint64_t toMachAbsoluteTime() const;
#endif
WTF_EXPORT_PRIVATE static MonotonicTime now();
MonotonicTime approximateMonotonicTime() const { return *this; }
WTF_EXPORT_PRIVATE WallTime approximateWallTime() const;
WTF_EXPORT_PRIVATE void dump(PrintStream&) const;
struct MarkableTraits;
private:
friend class GenericTimeMixin<MonotonicTime>;
constexpr MonotonicTime(double rawValue)
: GenericTimeMixin<MonotonicTime>(rawValue)
{
}
};
static_assert(sizeof(MonotonicTime) == sizeof(double));
struct MonotonicTime::MarkableTraits {
static bool isEmptyValue(MonotonicTime time)
{
return std::isnan(time.m_value);
}
static constexpr MonotonicTime emptyValue()
{
return MonotonicTime::nan();
}
};
} // namespace WTF
namespace std {
inline bool isnan(WTF::MonotonicTime time)
{
return std::isnan(time.secondsSinceEpoch().value());
}
inline bool isinf(WTF::MonotonicTime time)
{
return std::isinf(time.secondsSinceEpoch().value());
}
inline bool isfinite(WTF::MonotonicTime time)
{
return std::isfinite(time.secondsSinceEpoch().value());
}
} // namespace std
using WTF::MonotonicTime;
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