chromium/third_party/blink/renderer/core/animation/animation_time_delta.h

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_ANIMATION_ANIMATION_TIME_DELTA_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_ANIMATION_ANIMATION_TIME_DELTA_H_

#include "third_party/blink/renderer/core/animation/buildflags.h"

#include "base/time/time.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"

#include <limits>
#include <ostream>

namespace blink {

// AnimationTimeDelta exists to ease the transition of Blink animations from
// double-based time values to base::TimeDelta-based time values (see
// http://crbug.com/737867.
//
// It represents a delta between two times, analogous to base::TimeDelta. It is
// provided in two modes, based on a compiler flag. The first is the traditional
// (and default) double mode, where time deltas are represented using seconds in
// double-precision. The second mode uses base::TimeDelta to represent time
// instead.

#if !BUILDFLAG(BLINK_ANIMATION_USE_TIME_DELTA)

// The double-based version of AnimationTimeDelta. Internally, time is stored as
// double-precision seconds.
//
// This class is modelled on the API from base::TimeDelta, with a lot of
// unnecessary methods stripped out.
class CORE_EXPORT AnimationTimeDelta { … };

template <typename T>
AnimationTimeDelta operator*(T a, AnimationTimeDelta td) { … }

// Comparison operators on AnimationTimeDelta.
bool CORE_EXPORT operator==(const AnimationTimeDelta& lhs,
                            const AnimationTimeDelta& rhs);
bool CORE_EXPORT operator!=(const AnimationTimeDelta& lhs,
                            const AnimationTimeDelta& rhs);
bool CORE_EXPORT operator>(const AnimationTimeDelta& lhs,
                           const AnimationTimeDelta& rhs);
bool CORE_EXPORT operator<(const AnimationTimeDelta& lhs,
                           const AnimationTimeDelta& rhs);
bool CORE_EXPORT operator>=(const AnimationTimeDelta& lhs,
                            const AnimationTimeDelta& rhs);
bool CORE_EXPORT operator<=(const AnimationTimeDelta& lhs,
                            const AnimationTimeDelta& rhs);

// Defined to allow DCHECK_EQ/etc to work with the class.
CORE_EXPORT std::ostream& operator<<(std::ostream& os,
                                     const AnimationTimeDelta& time);

#else  // !BUILDFLAG(BLINK_ANIMATION_USE_TIME_DELTA)

// When compiling in TimeDelta-based mode, AnimationTimeDelta is equivalent to
// base::TimeDelta.
using AnimationTimeDelta = base::TimeDelta;

#define ANIMATION_TIME_DELTA_FROM_SECONDS …
#define ANIMATION_TIME_DELTA_FROM_MILLISECONDS …

#endif

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_ANIMATION_ANIMATION_TIME_DELTA_H_