+
−// Copyright 2012 The Chromium Authors
+
−// Use of this source code is governed by a BSD-style license that can be
+
−// found in the LICENSE file.
+
−
+
−// `Time` represents an absolute point in coordinated universal time (UTC),
+
−// internally represented as microseconds (s/1,000,000) since the Windows epoch
+
−// (1601-01-01 00:00:00 UTC). System-dependent clock interface routines are
+
−// defined in time_PLATFORM.cc. Note that values for `Time` may skew and jump
+
−// around as the operating system makes adjustments to synchronize (e.g., with
+
−// NTP servers). Thus, client code that uses the `Time` class must account for
+
−// this.
+
−//
+
−// `TimeDelta` represents a duration of time, internally represented in
+
−// microseconds.
+
−//
+
−// `TimeTicks` and `ThreadTicks` represent an abstract time that is most of the
+
−// time incrementing, for use in measuring time durations. Internally, they are
+
−// represented in microseconds. They cannot be converted to a human-readable
+
−// time, but are guaranteed not to decrease (unlike the `Time` class). Note
+
−// that `TimeTicks` may "stand still" (e.g., if the computer is suspended), and
+
−// `ThreadTicks` will "stand still" whenever the thread has been de-scheduled
+
−// by the operating system.
+
−//
+
−// All time classes are copyable, assignable, and occupy 64 bits per instance.
+
−// Prefer to pass them by value, e.g.:
+
−//
+
−//   void MyFunction(TimeDelta arg);
+
−//
+
−// All time classes support `operator<<` with logging streams, e.g. `LOG(INFO)`.
+
−// For human-readable formatting, use //base/i18n/time_formatting.h.
+
−//
+
−// Example use cases for different time classes:
+
−//
+
−//   Time:        Interpreting the wall-clock time provided by a remote system.
+
−//                Detecting whether cached resources have expired. Providing the
+
−//                user with a display of the current date and time. Determining
+
−//                the amount of time between events across re-boots of the
+
−//                machine.
+
−//
+
−//   TimeTicks:   Tracking the amount of time a task runs. Executing delayed
+
−//                tasks at the right time. Computing presentation timestamps.
+
−//                Synchronizing audio and video using TimeTicks as a common
+
−//                reference clock (lip-sync). Measuring network round-trip
+
−//                latency.
+
−//
+
−//   ThreadTicks: Benchmarking how long the current thread has been doing actual
+
−//                work.
+
−//
+
−// Serialization:
+
−//
+
−// Use the helpers in //base/json/values_util.h when serializing `Time`
+
−// or `TimeDelta` to/from `base::Value`.
+
−//
+
−// Otherwise:
+
−//
+
−// - Time: use `FromDeltaSinceWindowsEpoch()`/`ToDeltaSinceWindowsEpoch()`.
+
−// - TimeDelta: use `base::Microseconds()`/`InMicroseconds()`.
+
−//
+
−// `TimeTicks` and `ThreadTicks` do not have a stable origin; serialization for
+
−// the purpose of persistence is not supported.
+
−
+
−#ifndef BASE_TIME_TIME_H_
+
−#define BASE_TIME_TIME_H_
+
−
+
−#include <stdint.h>
+
−#include <time.h>
+
−
+
−#include <iosfwd>
+
−#include <limits>
+
−#include <ostream>
+
−
+
−#include "base/base_export.h"
+
−#include "base/check.h"
+
−#include "base/check_op.h"
+
−#include "base/compiler_specific.h"
+
−#include "base/numerics/clamped_math.h"
+
−#include "build/build_config.h"
+
−#include "build/chromeos_buildflags.h"
+
−
+
−#if BUILDFLAG(IS_APPLE)
+
−#include "base/time/buildflags/buildflags.h"
+
−#endif
+
−
+
−#if BUILDFLAG(IS_FUCHSIA)
+
−#include <zircon/types.h>
+
−#endif
+
−
+
−#if BUILDFLAG(IS_APPLE)
+
−#include <CoreFoundation/CoreFoundation.h>
+
−#include <mach/mach_time.h>
+
−// Avoid Mac system header macro leak.
+
−#undef TYPE_BOOL
+
−#endif
+
−
+
−#if BUILDFLAG(IS_ANDROID)
+
−#include <jni.h>
+
−#endif
+
−
+
−#if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
+
−#include <unistd.h>
+
−#include <sys/time.h>
+
−#endif
+
−
+
−#if BUILDFLAG(IS_WIN)
+
−#include "base/gtest_prod_util.h"
+
−#include "base/win/windows_types.h"
+
−
+
−namespace ABI {
+
−namespace Windows {
+
−namespace Foundation {
+
−struct DateTime;
+
−struct TimeSpan;
+
−}  // namespace Foundation
+
−}  // namespace Windows
+
−}  // namespace ABI
+
−#endif
+
−
+
−namespace base {
+
−
+
−class PlatformThreadHandle;
+
−class TimeDelta;
+
−
+
−template <typename T>
+
−constexpr TimeDelta Microseconds(T n);
+
−
+
−// TimeDelta ------------------------------------------------------------------
+
−
+
−class BASE_EXPORT TimeDelta {
+
− public:
+
−  constexpr TimeDelta() = default;
+
−
+
−#if BUILDFLAG(IS_WIN)
+
−  static TimeDelta FromQPCValue(LONGLONG qpc_value);
+
−  // TODO(crbug.com/989694): Avoid base::TimeDelta factory functions
+
−  // based on absolute time
+
−  static TimeDelta FromFileTime(FILETIME ft);
+
−  static TimeDelta FromWinrtDateTime(ABI::Windows::Foundation::DateTime dt);
+
−  static TimeDelta FromWinrtTimeSpan(ABI::Windows::Foundation::TimeSpan ts);
+
−#elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
+
−  static TimeDelta FromTimeSpec(const timespec& ts);
+
−#endif
+
−#if BUILDFLAG(IS_FUCHSIA)
+
−  static TimeDelta FromZxDuration(zx_duration_t nanos);
+
−#endif
+
−#if BUILDFLAG(IS_APPLE)
+
−#if BUILDFLAG(ENABLE_MACH_ABSOLUTE_TIME_TICKS)
+
−  static TimeDelta FromMachTime(uint64_t mach_time);
+
−#endif  // BUILDFLAG(ENABLE_MACH_ABSOLUTE_TIME_TICKS)
+
−#endif  // BUILDFLAG(IS_APPLE)
+
−
+
−  // Converts an integer value representing TimeDelta to a class. This is used
+
−  // when deserializing a |TimeDelta| structure, using a value known to be
+
−  // compatible. It is not provided as a constructor because the integer type
+
−  // may be unclear from the perspective of a caller.
+
−  //
+
−  // DEPRECATED - Do not use in new code. http://crbug.com/634507
+
−  static constexpr TimeDelta FromInternalValue(int64_t delta) {
+
−    return TimeDelta(delta);
+
−  }
+
−
+
−  // Returns the maximum time delta, which should be greater than any reasonable
+
−  // time delta we might compare it to. If converted to double with ToDouble()
+
−  // it becomes an IEEE double infinity. Use FiniteMax() if you want a very
+
−  // large number that doesn't do this. TimeDelta math saturates at the end
+
−  // points so adding to TimeDelta::Max() leaves the value unchanged.
+
−  // Subtracting should leave the value unchanged but currently changes it
+
−  // TODO(https://crbug.com/869387).
+
−  static constexpr TimeDelta Max();
+
−
+
−  // Returns the minimum time delta, which should be less than than any
+
−  // reasonable time delta we might compare it to. For more details see the
+
−  // comments for Max().
+
−  static constexpr TimeDelta Min();
+
−
+
−  // Returns the maximum time delta which is not equivalent to infinity. Only
+
−  // subtracting a finite time delta from this time delta has a defined result.
+
−  static constexpr TimeDelta FiniteMax();
+
−
+
−  // Returns the minimum time delta which is not equivalent to -infinity. Only
+
−  // adding a finite time delta to this time delta has a defined result.
+
−  static constexpr TimeDelta FiniteMin();
+
−
+
−  // Returns the internal numeric value of the TimeDelta object. Please don't
+
−  // use this and do arithmetic on it, as it is more error prone than using the
+
−  // provided operators.
+
−  // For serializing, use FromInternalValue to reconstitute.
+
−  //
+
−  // DEPRECATED - Do not use in new code. http://crbug.com/634507
+
−  constexpr int64_t ToInternalValue() const { return delta_; }
+
−
+
−  // Returns the magnitude (absolute value) of this TimeDelta.
+
−  constexpr TimeDelta magnitude() const { return TimeDelta(delta_.Abs()); }
+
−
+
−  // Returns true if the time delta is a zero, positive or negative time delta.
+
−  constexpr bool is_zero() const { return delta_ == 0; }
+
−  constexpr bool is_positive() const { return delta_ > 0; }
+
−  constexpr bool is_negative() const { return delta_ < 0; }
+
−
+
−  // Returns true if the time delta is the maximum/minimum time delta.
+
−  constexpr bool is_max() const { return *this == Max(); }
+
−  constexpr bool is_min() const { return *this == Min(); }
+
−  constexpr bool is_inf() const { return is_min() || is_max(); }
+
−
+
−#if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
+
−  struct timespec ToTimeSpec() const;
+
−#endif
+
−#if BUILDFLAG(IS_FUCHSIA)
+
−  zx_duration_t ToZxDuration() const;
+
−#endif
+
−#if BUILDFLAG(IS_WIN)
+
−  ABI::Windows::Foundation::DateTime ToWinrtDateTime() const;
+
−  ABI::Windows::Foundation::TimeSpan ToWinrtTimeSpan() const;
+
−#endif
+
−
+
−  // Returns the frequency in Hertz (cycles per second) that has a period of
+
−  // *this.
+
−  constexpr double ToHz() const;
+
−
+
−  // Returns the time delta in some unit. Minimum argument values return as
+
−  // -inf for doubles and min type values otherwise. Maximum ones are treated as
+
−  // +inf for doubles and max type values otherwise. Their results will produce
+
−  // an is_min() or is_max() TimeDelta. The InXYZF versions return a floating
+
−  // point value. The InXYZ versions return a truncated value (aka rounded
+
−  // towards zero, std::trunc() behavior). The InXYZFloored() versions round to
+
−  // lesser integers (std::floor() behavior). The XYZRoundedUp() versions round
+
−  // up to greater integers (std::ceil() behavior). WARNING: Floating point
+
−  // arithmetic is such that XXX(t.InXXXF()) may not precisely equal |t|.
+
−  // Hence, floating point values should not be used for storage.
+
−  constexpr int InDays() const;
+
−  constexpr int InDaysFloored() const;
+
−  constexpr int InHours() const;
+
−  constexpr int InMinutes() const;
+
−  constexpr double InSecondsF() const;
+
−  constexpr int64_t InSeconds() const;
+
−  constexpr int64_t InSecondsFloored() const;
+
−  constexpr double InMillisecondsF() const;
+
−  constexpr int64_t InMilliseconds() const;
+
−  constexpr int64_t InMillisecondsRoundedUp() const;
+
−  constexpr int64_t InMicroseconds() const { return delta_; }
+
−  constexpr double InMicrosecondsF() const;
+
−  constexpr int64_t InNanoseconds() const;
+
−
+
−  // Computations with other deltas.
+
−  constexpr TimeDelta operator+(TimeDelta other) const;
+
−  constexpr TimeDelta operator-(TimeDelta other) const;
+
−
+
−  constexpr TimeDelta& operator+=(TimeDelta other) {
+
−    return *this = (*this + other);
+
−  }
+
−  constexpr TimeDelta& operator-=(TimeDelta other) {
+
−    return *this = (*this - other);
+
−  }
+
−  constexpr TimeDelta operator-() const {
+
−    if (!is_inf())
+
−      return TimeDelta(-delta_);
+
−    return (delta_ < 0) ? Max() : Min();
+
−  }
+
−
+
−  // Computations with numeric types.
+
−  template <typename T>
+
−  constexpr TimeDelta operator*(T a) const {
+
−    return TimeDelta(int64_t{delta_ * a});
+
−  }
+
−  template <typename T>
+
−  constexpr TimeDelta operator/(T a) const {
+
−    return TimeDelta(int64_t{delta_ / a});
+
−  }
+
−  template <typename T>
+
−  constexpr TimeDelta& operator*=(T a) {
+
−    return *this = (*this * a);
+
−  }
+
−  template <typename T>
+
−  constexpr TimeDelta& operator/=(T a) {
+
−    return *this = (*this / a);
+
−  }
+
−
+
−  // This does floating-point division. For an integer result, either call
+
−  // IntDiv(), or (possibly clearer) use this operator with
+
−  // base::Clamp{Ceil,Floor,Round}() or base::saturated_cast() (for truncation).
+
−  // Note that converting to double here drops precision to 53 bits.
+
−  constexpr double operator/(TimeDelta a) const {
+
−    // 0/0 and inf/inf (any combination of positive and negative) are invalid
+
−    // (they are almost certainly not intentional, and result in NaN, which
+
−    // turns into 0 if clamped to an integer; this makes introducing subtle bugs
+
−    // too easy).
+
−    CHECK(!is_zero() || !a.is_zero());
+
−    CHECK(!is_inf() || !a.is_inf());
+
−
+
−    return ToDouble() / a.ToDouble();
+
−  }
+
−  constexpr int64_t IntDiv(TimeDelta a) const {
+
−    if (!is_inf() && !a.is_zero())
+
−      return int64_t{delta_ / a.delta_};
+
−
+
−    // For consistency, use the same edge case CHECKs and behavior as the code
+
−    // above.
+
−    CHECK(!is_zero() || !a.is_zero());
+
−    CHECK(!is_inf() || !a.is_inf());
+
−    return ((delta_ < 0) == (a.delta_ < 0))
+
−               ? std::numeric_limits<int64_t>::max()
+
−               : std::numeric_limits<int64_t>::min();
+
−  }
+
−
+
−  constexpr TimeDelta operator%(TimeDelta a) const {
+
−    return TimeDelta(
+
−        (is_inf() || a.is_zero() || a.is_inf()) ? delta_ : (delta_ % a.delta_));
+
−  }
+
−  constexpr TimeDelta& operator%=(TimeDelta other) {
+
−    return *this = (*this % other);
+
−  }
+
−
+
−  // Comparison operators.
+
−  constexpr bool operator==(TimeDelta other) const {
+
−    return delta_ == other.delta_;
+
−  }
+
−  constexpr bool operator!=(TimeDelta other) const {
+
−    return delta_ != other.delta_;
+
−  }
+
−  constexpr bool operator<(TimeDelta other) const {
+
−    return delta_ < other.delta_;
+
−  }
+
−  constexpr bool operator<=(TimeDelta other) const {
+
−    return delta_ <= other.delta_;
+
−  }
+
−  constexpr bool operator>(TimeDelta other) const {
+
−    return delta_ > other.delta_;
+
−  }
+
−  constexpr bool operator>=(TimeDelta other) const {
+
−    return delta_ >= other.delta_;
+
−  }
+
−
+
−  // Returns this delta, ceiled/floored/rounded-away-from-zero to the nearest
+
−  // multiple of |interval|.
+
−  TimeDelta CeilToMultiple(TimeDelta interval) const;
+
−  TimeDelta FloorToMultiple(TimeDelta interval) const;
+
−  TimeDelta RoundToMultiple(TimeDelta interval) const;
+
−
+
− private:
+
−  // Constructs a delta given the duration in microseconds. This is private
+
−  // to avoid confusion by callers with an integer constructor. Use
+
−  // base::Seconds, base::Milliseconds, etc. instead.
+
−  constexpr explicit TimeDelta(int64_t delta_us) : delta_(delta_us) {}
+
−  constexpr explicit TimeDelta(ClampedNumeric<int64_t> delta_us)
+
−      : delta_(delta_us) {}
+
−
+
−  // Returns a double representation of this TimeDelta's tick count.  In
+
−  // particular, Max()/Min() are converted to +/-infinity.
+
−  constexpr double ToDouble() const {
+
−    if (!is_inf())
+
−      return static_cast<double>(delta_);
+
−    return (delta_ < 0) ? -std::numeric_limits<double>::infinity()
+
−                        : std::numeric_limits<double>::infinity();
+
−  }
+
−
+
−  // Delta in microseconds.
+
−  ClampedNumeric<int64_t> delta_ = 0;
+
−};
+
−
+
−constexpr TimeDelta TimeDelta::operator+(TimeDelta other) const {
+
−  if (!other.is_inf())
+
−    return TimeDelta(delta_ + other.delta_);
+
−
+
−  // Additions involving two infinities are only valid if signs match.
+
−  CHECK(!is_inf() || (delta_ == other.delta_));
+
−  return other;
+
−}
+
−
+
−constexpr TimeDelta TimeDelta::operator-(TimeDelta other) const {
+
−  if (!other.is_inf())
+
−    return TimeDelta(delta_ - other.delta_);
+
−
+
−  // Subtractions involving two infinities are only valid if signs differ.
+
−  CHECK_NE(int64_t{delta_}, int64_t{other.delta_});
+
−  return (other.delta_ < 0) ? Max() : Min();
+
−}
+
−
+
−template <typename T>
+
−constexpr TimeDelta operator*(T a, TimeDelta td) {
+
−  return td * a;
+
−}
+
−
+
−// For logging use only.
+
−BASE_EXPORT std::ostream& operator<<(std::ostream& os, TimeDelta time_delta);
+
−
+
−// TimeBase--------------------------------------------------------------------
+
−
+
−// Do not reference the time_internal::TimeBase template class directly.  Please
+
−// use one of the time subclasses instead, and only reference the public
+
−// TimeBase members via those classes.
+
−namespace time_internal {
+
−
+
−// Provides value storage and comparison/math operations common to all time
+
−// classes. Each subclass provides for strong type-checking to ensure
+
−// semantically meaningful comparison/math of time values from the same clock
+
−// source or timeline.
+
−template<class TimeClass>
+
−class TimeBase {
+
− public:
+
−  static constexpr int64_t kHoursPerDay = 24;
+
−  static constexpr int64_t kSecondsPerMinute = 60;
+
−  static constexpr int64_t kMinutesPerHour = 60;
+
−  static constexpr int64_t kSecondsPerHour =
+
−      kSecondsPerMinute * kMinutesPerHour;
+
−  static constexpr int64_t kMillisecondsPerSecond = 1000;
+
−  static constexpr int64_t kMillisecondsPerDay =
+
−      kMillisecondsPerSecond * kSecondsPerHour * kHoursPerDay;
+
−  static constexpr int64_t kMicrosecondsPerMillisecond = 1000;
+
−  static constexpr int64_t kMicrosecondsPerSecond =
+
−      kMicrosecondsPerMillisecond * kMillisecondsPerSecond;
+
−  static constexpr int64_t kMicrosecondsPerMinute =
+
−      kMicrosecondsPerSecond * kSecondsPerMinute;
+
−  static constexpr int64_t kMicrosecondsPerHour =
+
−      kMicrosecondsPerMinute * kMinutesPerHour;
+
−  static constexpr int64_t kMicrosecondsPerDay =
+
−      kMicrosecondsPerHour * kHoursPerDay;
+
−  static constexpr int64_t kMicrosecondsPerWeek = kMicrosecondsPerDay * 7;
+
−  static constexpr int64_t kNanosecondsPerMicrosecond = 1000;
+
−  static constexpr int64_t kNanosecondsPerSecond =
+
−      kNanosecondsPerMicrosecond * kMicrosecondsPerSecond;
+
−
+
−  // TODO(https://crbug.com/1392437): Remove concept of "null" from base::Time.
+
−  //
+
−  // Warning: Be careful when writing code that performs math on time values,
+
−  // since it's possible to produce a valid "zero" result that should not be
+
−  // interpreted as a "null" value. If you find yourself using this method or
+
−  // the zero-arg default constructor, please consider using an optional to
+
−  // express the null state.
+
−  //
+
−  // Returns true if this object has not been initialized (probably).
+
−  constexpr bool is_null() const { return us_ == 0; }
+
−
+
−  // Returns true if this object represents the maximum/minimum time.
+
−  constexpr bool is_max() const { return *this == Max(); }
+
−  constexpr bool is_min() const { return *this == Min(); }
+
−  constexpr bool is_inf() const { return is_min() || is_max(); }
+
−
+
−  // Returns the maximum/minimum times, which should be greater/less than than
+
−  // any reasonable time with which we might compare it.
+
−  static constexpr TimeClass Max() {
+
−    return TimeClass(std::numeric_limits<int64_t>::max());
+
−  }
+
−
+
−  static constexpr TimeClass Min() {
+
−    return TimeClass(std::numeric_limits<int64_t>::min());
+
−  }
+
−
+
−  // For legacy serialization only. When serializing to `base::Value`, prefer
+
−  // the helpers from //base/json/values_util.h instead. Otherwise, use
+
−  // `Time::ToDeltaSinceWindowsEpoch()` for `Time` and
+
−  // `TimeDelta::InMicroseconds()` for `TimeDelta`. See http://crbug.com/634507.
+
−  constexpr int64_t ToInternalValue() const { return us_; }
+
−
+
−  // The amount of time since the origin (or "zero") point. This is a syntactic
+
−  // convenience to aid in code readability, mainly for debugging/testing use
+
−  // cases.
+
−  //
+
−  // Warning: While the Time subclass has a fixed origin point, the origin for
+
−  // the other subclasses can vary each time the application is restarted.
+
−  constexpr TimeDelta since_origin() const;
+
−
+
−  // Compute the difference between two times.
+
−#if !defined(__aarch64__) && BUILDFLAG(IS_ANDROID)
+
−  NOINLINE  // https://crbug.com/1369775
+
−#endif
+
−  constexpr TimeDelta operator-(const TimeBase<TimeClass>& other) const;
+
−
+
−  // Return a new time modified by some delta.
+
−  constexpr TimeClass operator+(TimeDelta delta) const;
+
−  constexpr TimeClass operator-(TimeDelta delta) const;
+
−
+
−  // Modify by some time delta.
+
−  constexpr TimeClass& operator+=(TimeDelta delta) {
+
−    return static_cast<TimeClass&>(*this = (*this + delta));
+
−  }
+
−  constexpr TimeClass& operator-=(TimeDelta delta) {
+
−    return static_cast<TimeClass&>(*this = (*this - delta));
+
−  }
+
−
+
−  // Comparison operators
+
−  constexpr bool operator==(const TimeBase<TimeClass>& other) const {
+
−    return us_ == other.us_;
+
−  }
+
−  constexpr bool operator!=(const TimeBase<TimeClass>& other) const {
+
−    return us_ != other.us_;
+
−  }
+
−  constexpr bool operator<(const TimeBase<TimeClass>& other) const {
+
−    return us_ < other.us_;
+
−  }
+
−  constexpr bool operator<=(const TimeBase<TimeClass>& other) const {
+
−    return us_ <= other.us_;
+
−  }
+
−  constexpr bool operator>(const TimeBase<TimeClass>& other) const {
+
−    return us_ > other.us_;
+
−  }
+
−  constexpr bool operator>=(const TimeBase<TimeClass>& other) const {
+
−    return us_ >= other.us_;
+
−  }
+
−
+
− protected:
+
−  constexpr explicit TimeBase(int64_t us) : us_(us) {}
+
−
+
−  // Time value in a microsecond timebase.
+
−  ClampedNumeric<int64_t> us_;
+
−};
+
−
+
−#if BUILDFLAG(IS_WIN)
+
−#if defined(ARCH_CPU_ARM64)
+
−// TSCTicksPerSecond is not supported on Windows on Arm systems because the
+
−// cycle-counting methods use the actual CPU cycle count, and not a consistent
+
−// incrementing counter.
+
−#else
+
−// Returns true if the CPU support constant rate TSC.
+
−[[nodiscard]] BASE_EXPORT bool HasConstantRateTSC();
+
−
+
−// Returns the frequency of the TSC in ticks per second, or 0 if it hasn't
+
−// been measured yet. Needs to be guarded with a call to HasConstantRateTSC().
+
−[[nodiscard]] BASE_EXPORT double TSCTicksPerSecond();
+
−#endif
+
−#endif  // BUILDFLAG(IS_WIN)
+
−
+
−}  // namespace time_internal
+
−
+
−template <class TimeClass>
+
−inline constexpr TimeClass operator+(TimeDelta delta, TimeClass t) {
+
−  return t + delta;
+
−}
+
−
+
−// Time -----------------------------------------------------------------------
+
−
+
−// Represents a wall clock time in UTC. Values are not guaranteed to be
+
−// monotonically non-decreasing and are subject to large amounts of skew.
+
−// Time is stored internally as microseconds since the Windows epoch (1601).
+
−class BASE_EXPORT Time : public time_internal::TimeBase<Time> {
+
− public:
+
−  // Offset of UNIX epoch (1970-01-01 00:00:00 UTC) from Windows FILETIME epoch
+
−  // (1601-01-01 00:00:00 UTC), in microseconds. This value is derived from the
+
−  // following: ((1970-1601)*365+89)*24*60*60*1000*1000, where 89 is the number
+
−  // of leap year days between 1601 and 1970: (1970-1601)/4 excluding 1700,
+
−  // 1800, and 1900.
+
−  static constexpr int64_t kTimeTToMicrosecondsOffset =
+
−      INT64_C(11644473600000000);
+
−
+
−#if BUILDFLAG(IS_WIN)
+
−  // To avoid overflow in QPC to Microseconds calculations, since we multiply
+
−  // by kMicrosecondsPerSecond, then the QPC value should not exceed
+
−  // (2^63 - 1) / 1E6. If it exceeds that threshold, we divide then multiply.
+
−  static constexpr int64_t kQPCOverflowThreshold = INT64_C(0x8637BD05AF7);
+
−#endif
+
−
+
−// kExplodedMinYear and kExplodedMaxYear define the platform-specific limits
+
−// for values passed to FromUTCExploded() and FromLocalExploded(). Those
+
−// functions will return false if passed values outside these limits. The limits
+
−// are inclusive, meaning that the API should support all dates within a given
+
−// limit year.
+
−//
+
−// WARNING: These are not the same limits for the inverse functionality,
+
−// UTCExplode() and LocalExplode(). See method comments for further details.
+
−#if BUILDFLAG(IS_WIN)
+
−  static constexpr int kExplodedMinYear = 1601;
+
−  static constexpr int kExplodedMaxYear = 30827;
+
−#elif BUILDFLAG(IS_IOS) && !__LP64__
+
−  static constexpr int kExplodedMinYear = std::numeric_limits<int>::min();
+
−  static constexpr int kExplodedMaxYear = std::numeric_limits<int>::max();
+
−#elif BUILDFLAG(IS_APPLE)
+
−  static constexpr int kExplodedMinYear = 1902;
+
−  static constexpr int kExplodedMaxYear = std::numeric_limits<int>::max();
+
−#elif BUILDFLAG(IS_ANDROID)
+
−  // Though we use 64-bit time APIs on both 32 and 64 bit Android, some OS
+
−  // versions like KitKat (ARM but not x86 emulator) can't handle some early
+
−  // dates (e.g. before 1170). So we set min conservatively here.
+
−  static constexpr int kExplodedMinYear = 1902;
+
−  static constexpr int kExplodedMaxYear = std::numeric_limits<int>::max();
+
−#else
+
−  static constexpr int kExplodedMinYear =
+
−      (sizeof(time_t) == 4 ? 1902 : std::numeric_limits<int>::min());
+
−  static constexpr int kExplodedMaxYear =
+
−      (sizeof(time_t) == 4 ? 2037 : std::numeric_limits<int>::max());
+
−#endif
+
−
+
−  // Represents an exploded time that can be formatted nicely. This is kind of
+
−  // like the Win32 SYSTEMTIME structure or the Unix "struct tm" with a few
+
−  // additions and changes to prevent errors.
+
−  // This structure always represents dates in the Gregorian calendar and always
+
−  // encodes day_of_week as Sunday==0, Monday==1, .., Saturday==6. This means
+
−  // that base::Time::LocalExplode and base::Time::FromLocalExploded only
+
−  // respect the current local time zone in the conversion and do *not* use a
+
−  // calendar or day-of-week encoding from the current locale.
+
−  struct BASE_EXPORT Exploded {
+
−    int year;          // Four digit year "2007"
+
−    int month;         // 1-based month (values 1 = January, etc.)
+
−    int day_of_week;   // 0-based day of week (0 = Sunday, etc.)
+
−    int day_of_month;  // 1-based day of month (1-31)
+
−    int hour;          // Hour within the current day (0-23)
+
−    int minute;        // Minute within the current hour (0-59)
+
−    int second;        // Second within the current minute (0-59 plus leap
+
−                       //   seconds which may take it up to 60).
+
−    int millisecond;   // Milliseconds within the current second (0-999)
+
−
+
−    // A cursory test for whether the data members are within their
+
−    // respective ranges. A 'true' return value does not guarantee the
+
−    // Exploded value can be successfully converted to a Time value.
+
−    bool HasValidValues() const;
+
−  };
+
−
+
−  // TODO(https://crbug.com/1392437): Remove concept of "null" from base::Time.
+
−  //
+
−  // Warning: Be careful when writing code that performs math on time values,
+
−  // since it's possible to produce a valid "zero" result that should not be
+
−  // interpreted as a "null" value. If you find yourself using this constructor
+
−  // or the is_null() method, please consider using an optional to express the
+
−  // null state.
+
−  //
+
−  // Contains the NULL time. Use Time::Now() to get the current time.
+
−  constexpr Time() : TimeBase(0) {}
+
−
+
−  // Returns the time for epoch in Unix-like system (Jan 1, 1970).
+
−  static constexpr Time UnixEpoch() { return Time(kTimeTToMicrosecondsOffset); }
+
−
+
−  // Returns the current time. Watch out, the system might adjust its clock
+
−  // in which case time will actually go backwards. We don't guarantee that
+
−  // times are increasing, or that two calls to Now() won't be the same.
+
−  static Time Now();
+
−
+
−  // Returns the current time. Same as Now() except that this function always
+
−  // uses system time so that there are no discrepancies between the returned
+
−  // time and system time even on virtual environments including our test bot.
+
−  // For timing sensitive unittests, this function should be used.
+
−  static Time NowFromSystemTime();
+
−
+
−  // Converts to/from TimeDeltas relative to the Windows epoch (1601-01-01
+
−  // 00:00:00 UTC).
+
−  //
+
−  // For serialization, when handling `base::Value`, prefer the helpers in
+
−  // //base/json/values_util.h instead. Otherwise, use these methods for
+
−  // opaque serialization and deserialization, e.g.
+
−  //
+
−  //   // Serialization:
+
−  //   base::Time last_updated = ...;
+
−  //   SaveToDatabase(last_updated.ToDeltaSinceWindowsEpoch().InMicroseconds());
+
−  //
+
−  //   // Deserialization:
+
−  //   base::Time last_updated = base::Time::FromDeltaSinceWindowsEpoch(
+
−  //       base::Microseconds(LoadFromDatabase()));
+
−  //
+
−  // Do not use `FromInternalValue()` or `ToInternalValue()` for this purpose.
+
−  static constexpr Time FromDeltaSinceWindowsEpoch(TimeDelta delta) {
+
−    return Time(delta.InMicroseconds());
+
−  }
+
−
+
−  constexpr TimeDelta ToDeltaSinceWindowsEpoch() const {
+
−    return Microseconds(us_);
+
−  }
+
−
+
−  // Converts to/from time_t in UTC and a Time class.
+
−  static constexpr Time FromTimeT(time_t tt);
+
−  constexpr time_t ToTimeT() const;
+
−
+
−  // Converts time to/from a double which is the number of seconds since epoch
+
−  // (Jan 1, 1970).  Webkit uses this format to represent time.
+
−  // Because WebKit initializes double time value to 0 to indicate "not
+
−  // initialized", we map it to empty Time object that also means "not
+
−  // initialized".
+
−  static constexpr Time FromDoubleT(double dt);
+
−  constexpr double ToDoubleT() const;
+
−
+
−#if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
+
−  // Converts the timespec structure to time. MacOS X 10.8.3 (and tentatively,
+
−  // earlier versions) will have the |ts|'s tv_nsec component zeroed out,
+
−  // having a 1 second resolution, which agrees with
+
−  // https://developer.apple.com/legacy/library/#technotes/tn/tn1150.html#HFSPlusDates.
+
−  static constexpr Time FromTimeSpec(const timespec& ts);
+
−#endif
+
−
+
−  // Converts to/from the Javascript convention for times, a number of
+
−  // milliseconds since the epoch:
+
−  // https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Date/getTime.
+
−  //
+
−  // Don't use ToJsTime() in new code, since it contains a subtle hack (only
+
−  // exactly 1601-01-01 00:00 UTC is represented as 1970-01-01 00:00 UTC), and
+
−  // that is not appropriate for general use. Try to use ToJsTimeIgnoringNull()
+
−  // unless you have a very good reason to use ToJsTime().
+
−  static constexpr Time FromJsTime(double ms_since_epoch);
+
−  constexpr double ToJsTime() const;
+
−  constexpr double ToJsTimeIgnoringNull() const;
+
−
+
−  // Converts to/from Java convention for times, a number of milliseconds since
+
−  // the epoch. Because the Java format has less resolution, converting to Java
+
−  // time is a lossy operation.
+
−  static constexpr Time FromJavaTime(int64_t ms_since_epoch);
+
−  constexpr int64_t ToJavaTime() const;
+
−
+
−#if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
+
−  static Time FromTimeVal(struct timeval t);
+
−  struct timeval ToTimeVal() const;
+
−#endif
+
−
+
−#if BUILDFLAG(IS_FUCHSIA)
+
−  static Time FromZxTime(zx_time_t time);
+
−  zx_time_t ToZxTime() const;
+
−#endif
+
−
+
−#if BUILDFLAG(IS_APPLE)
+
−  static Time FromCFAbsoluteTime(CFAbsoluteTime t);
+
−  CFAbsoluteTime ToCFAbsoluteTime() const;
+
−#if defined(__OBJC__)
+
−  static Time FromNSDate(NSDate* date);
+
−  NSDate* ToNSDate() const;
+
−#endif
+
−#endif
+
−
+
−#if BUILDFLAG(IS_WIN)
+
−  static Time FromFileTime(FILETIME ft);
+
−  FILETIME ToFileTime() const;
+
−
+
−  // The minimum time of a low resolution timer.  This is basically a windows
+
−  // constant of ~15.6ms.  While it does vary on some older OS versions, we'll
+
−  // treat it as static across all windows versions.
+
−  static const int kMinLowResolutionThresholdMs = 16;
+
−
+
−  // Enable or disable Windows high resolution timer.
+
−  static void EnableHighResolutionTimer(bool enable);
+
−
+
−  // Activates or deactivates the high resolution timer based on the |activate|
+
−  // flag.  If the HighResolutionTimer is not Enabled (see
+
−  // EnableHighResolutionTimer), this function will return false.  Otherwise
+
−  // returns true.  Each successful activate call must be paired with a
+
−  // subsequent deactivate call.
+
−  // All callers to activate the high resolution timer must eventually call
+
−  // this function to deactivate the high resolution timer.
+
−  static bool ActivateHighResolutionTimer(bool activate);
+
−
+
−  // Returns true if the high resolution timer is both enabled and activated.
+
−  // This is provided for testing only, and is not tracked in a thread-safe
+
−  // way.
+
−  static bool IsHighResolutionTimerInUse();
+
−
+
−  // The following two functions are used to report the fraction of elapsed time
+
−  // that the high resolution timer is activated.
+
−  // ResetHighResolutionTimerUsage() resets the cumulative usage and starts the
+
−  // measurement interval and GetHighResolutionTimerUsage() returns the
+
−  // percentage of time since the reset that the high resolution timer was
+
−  // activated.
+
−  // ResetHighResolutionTimerUsage() must be called at least once before calling
+
−  // GetHighResolutionTimerUsage(); otherwise the usage result would be
+
−  // undefined.
+
−  static void ResetHighResolutionTimerUsage();
+
−  static double GetHighResolutionTimerUsage();
+
−#endif  // BUILDFLAG(IS_WIN)
+
−
+
−  // Converts an exploded structure representing either the local time or UTC
+
−  // into a Time class. Returns false on a failure when, for example, a day of
+
−  // month is set to 31 on a 28-30 day month. Returns Time(0) on overflow.
+
−  // FromLocalExploded respects the current time zone but does not attempt to
+
−  // use the calendar or day-of-week encoding from the current locale - see the
+
−  // comments on base::Time::Exploded for more information.
+
−  [[nodiscard]] static bool FromUTCExploded(const Exploded& exploded,
+
−                                            Time* time) {
+
−    return FromExploded(false, exploded, time);
+
−  }
+
−  [[nodiscard]] static bool FromLocalExploded(const Exploded& exploded,
+
−                                              Time* time) {
+
−    return FromExploded(true, exploded, time);
+
−  }
+
−
+
−  // Converts a string representation of time to a Time object.
+
−  // An example of a time string which is converted is as below:-
+
−  // "Tue, 15 Nov 1994 12:45:26 GMT". If the timezone is not specified
+
−  // in the input string, FromString assumes local time and FromUTCString
+
−  // assumes UTC. A timezone that cannot be parsed (e.g. "UTC" which is not
+
−  // specified in RFC822) is treated as if the timezone is not specified.
+
−  //
+
−  // WARNING: the underlying converter is very permissive. For example: it is
+
−  // not checked whether a given day of the week matches the date; Feb 29
+
−  // silently becomes Mar 1 in non-leap years; under certain conditions, whole
+
−  // English sentences may be parsed successfully and yield unexpected results.
+
−  //
+
−  // TODO(iyengar) Move the FromString/FromTimeT/ToTimeT/FromFileTime to
+
−  // a new time converter class.
+
−  [[nodiscard]] static bool FromString(const char* time_string,
+
−                                       Time* parsed_time) {
+
−    return FromStringInternal(time_string, true, parsed_time);
+
−  }
+
−  [[nodiscard]] static bool FromUTCString(const char* time_string,
+
−                                          Time* parsed_time) {
+
−    return FromStringInternal(time_string, false, parsed_time);
+
−  }
+
−
+
−  // Fills the given |exploded| structure with either the local time or UTC from
+
−  // this Time instance. If the conversion cannot be made, the output will be
+
−  // assigned invalid values. Use Exploded::HasValidValues() to confirm a
+
−  // successful conversion.
+
−  //
+
−  // Y10K compliance: This method will successfully convert all Times that
+
−  // represent dates on/after the start of the year 1601 and on/before the start
+
−  // of the year 30828. Some platforms might convert over a wider input range.
+
−  // LocalExplode respects the current time zone but does not attempt to use the
+
−  // calendar or day-of-week encoding from the current locale - see the comments
+
−  // on base::Time::Exploded for more information.
+
−  void UTCExplode(Exploded* exploded) const { Explode(false, exploded); }
+
−  void LocalExplode(Exploded* exploded) const { Explode(true, exploded); }
+
−
+
−  // The following two functions round down the time to the nearest day in
+
−  // either UTC or local time. It will represent midnight on that day.
+
−  Time UTCMidnight() const { return Midnight(false); }
+
−  Time LocalMidnight() const { return Midnight(true); }
+
−
+
−  // For legacy deserialization only. Converts an integer value representing
+
−  // Time to a class. This may be used when deserializing a |Time| structure,
+
−  // using a value known to be compatible. It is not provided as a constructor
+
−  // because the integer type may be unclear from the perspective of a caller.
+
−  //
+
−  // DEPRECATED - Do not use in new code. When deserializing from `base::Value`,
+
−  // prefer the helpers from //base/json/values_util.h instead.
+
−  // Otherwise, use `Time::FromDeltaSinceWindowsEpoch()` for `Time` and
+
−  // `TimeDelta::FromMicroseconds()` for `TimeDelta`. http://crbug.com/634507
+
−  static constexpr Time FromInternalValue(int64_t us) { return Time(us); }
+
−
+
− private:
+
−  friend class time_internal::TimeBase<Time>;
+
−
+
−  constexpr explicit Time(int64_t microseconds_since_win_epoch)
+
−      : TimeBase(microseconds_since_win_epoch) {}
+
−
+
−  // Explodes the given time to either local time |is_local = true| or UTC
+
−  // |is_local = false|.
+
−  void Explode(bool is_local, Exploded* exploded) const;
+
−
+
−  // Unexplodes a given time assuming the source is either local time
+
−  // |is_local = true| or UTC |is_local = false|. Function returns false on
+
−  // failure and sets |time| to Time(0). Otherwise returns true and sets |time|
+
−  // to non-exploded time.
+
−  [[nodiscard]] static bool FromExploded(bool is_local,
+
−                                         const Exploded& exploded,
+
−                                         Time* time);
+
−
+
−  // Some platforms use the ICU library to provide To/FromExploded, when their
+
−  // native library implementations are insufficient in some way.
+
−  static void ExplodeUsingIcu(int64_t millis_since_unix_epoch,
+
−                              bool is_local,
+
−                              Exploded* exploded);
+
−  [[nodiscard]] static bool FromExplodedUsingIcu(
+
−      bool is_local,
+
−      const Exploded& exploded,
+
−      int64_t* millis_since_unix_epoch);
+
−
+
−  // Rounds down the time to the nearest day in either local time
+
−  // |is_local = true| or UTC |is_local = false|.
+
−  Time Midnight(bool is_local) const;
+
−
+
−  // Converts a string representation of time to a Time object.
+
−  // An example of a time string which is converted is as below:-
+
−  // "Tue, 15 Nov 1994 12:45:26 GMT". If the timezone is not specified
+
−  // in the input string, local time |is_local = true| or
+
−  // UTC |is_local = false| is assumed. A timezone that cannot be parsed
+
−  // (e.g. "UTC" which is not specified in RFC822) is treated as if the
+
−  // timezone is not specified.
+
−  [[nodiscard]] static bool FromStringInternal(const char* time_string,
+
−                                               bool is_local,
+
−                                               Time* parsed_time);
+
−
+
−  // Comparison does not consider |day_of_week| when doing the operation.
+
−  [[nodiscard]] static bool ExplodedMostlyEquals(const Exploded& lhs,
+
−                                                 const Exploded& rhs);
+
−
+
−  // Converts the provided time in milliseconds since the Unix epoch (1970) to a
+
−  // Time object, avoiding overflows.
+
−  [[nodiscard]] static bool FromMillisecondsSinceUnixEpoch(
+
−      int64_t unix_milliseconds,
+
−      Time* time);
+
−
+
−  // Returns the milliseconds since the Unix epoch (1970), rounding the
+
−  // microseconds towards -infinity.
+
−  int64_t ToRoundedDownMillisecondsSinceUnixEpoch() const;
+
−};
+
−
+
−// Factory methods that return a TimeDelta of the given unit.
+
−// WARNING: Floating point arithmetic is such that XXX(t.InXXXF()) may not
+
−// precisely equal |t|. Hence, floating point values should not be used for
+
−// storage.
+
−
+
−template <typename T>
+
−constexpr TimeDelta Days(T n) {
+
−  return TimeDelta::FromInternalValue(MakeClampedNum(n) *
+
−                                      Time::kMicrosecondsPerDay);
+
−}
+
−template <typename T>
+
−constexpr TimeDelta Hours(T n) {
+
−  return TimeDelta::FromInternalValue(MakeClampedNum(n) *
+
−                                      Time::kMicrosecondsPerHour);
+
−}
+
−template <typename T>
+
−constexpr TimeDelta Minutes(T n) {
+
−  return TimeDelta::FromInternalValue(MakeClampedNum(n) *
+
−                                      Time::kMicrosecondsPerMinute);
+
−}
+
−template <typename T>
+
−constexpr TimeDelta Seconds(T n) {
+
−  return TimeDelta::FromInternalValue(MakeClampedNum(n) *
+
−                                      Time::kMicrosecondsPerSecond);
+
−}
+
−template <typename T>
+
−constexpr TimeDelta Milliseconds(T n) {
+
−  return TimeDelta::FromInternalValue(MakeClampedNum(n) *
+
−                                      Time::kMicrosecondsPerMillisecond);
+
−}
+
−template <typename T>
+
−constexpr TimeDelta Microseconds(T n) {
+
−  return TimeDelta::FromInternalValue(MakeClampedNum(n));
+
−}
+
−template <typename T>
+
−constexpr TimeDelta Nanoseconds(T n) {
+
−  return TimeDelta::FromInternalValue(MakeClampedNum(n) /
+
−                                      Time::kNanosecondsPerMicrosecond);
+
−}
+
−template <typename T>
+
−constexpr TimeDelta Hertz(T n) {
+
−  return n ? TimeDelta::FromInternalValue(Time::kMicrosecondsPerSecond /
+
−                                          MakeClampedNum(n))
+
−           : TimeDelta::Max();
+
−}
+
−
+
−// TimeDelta functions that must appear below the declarations of Time/TimeDelta
+
−
+
−constexpr double TimeDelta::ToHz() const {
+
−  return Seconds(1) / *this;
+
−}
+
−
+
−constexpr int TimeDelta::InDays() const {
+
−  if (!is_inf()) {
+
−    return static_cast<int>(delta_ / Time::kMicrosecondsPerDay);
+
−  }
+
−  return (delta_ < 0) ? std::numeric_limits<int>::min()
+
−                      : std::numeric_limits<int>::max();
+
−}
+
−
+
−constexpr int TimeDelta::InDaysFloored() const {
+
−  if (!is_inf()) {
+
−    const int result = delta_ / Time::kMicrosecondsPerDay;
+
−    // Convert |result| from truncating to flooring.
+
−    return (result * Time::kMicrosecondsPerDay > delta_) ? (result - 1)
+
−                                                         : result;
+
−  }
+
−  return (delta_ < 0) ? std::numeric_limits<int>::min()
+
−                      : std::numeric_limits<int>::max();
+
−}
+
−
+
−constexpr int TimeDelta::InHours() const {
+
−  // saturated_cast<> is necessary since very large (but still less than
+
−  // min/max) deltas would result in overflow.
+
−  return saturated_cast<int>(delta_ / Time::kMicrosecondsPerHour);
+
−}
+
−
+
−constexpr int TimeDelta::InMinutes() const {
+
−  // saturated_cast<> is necessary since very large (but still less than
+
−  // min/max) deltas would result in overflow.
+
−  return saturated_cast<int>(delta_ / Time::kMicrosecondsPerMinute);
+
−}
+
−
+
−constexpr double TimeDelta::InSecondsF() const {
+
−  if (!is_inf())
+
−    return static_cast<double>(delta_) / Time::kMicrosecondsPerSecond;
+
−  return (delta_ < 0) ? -std::numeric_limits<double>::infinity()
+
−                      : std::numeric_limits<double>::infinity();
+
−}
+
−
+
−constexpr int64_t TimeDelta::InSeconds() const {
+
−  return is_inf() ? delta_ : (delta_ / Time::kMicrosecondsPerSecond);
+
−}
+
−
+
−constexpr int64_t TimeDelta::InSecondsFloored() const {
+
−  if (!is_inf()) {
+
−    const int64_t result = delta_ / Time::kMicrosecondsPerSecond;
+
−    // Convert |result| from truncating to flooring.
+
−    return (result * Time::kMicrosecondsPerSecond > delta_) ? (result - 1)
+
−                                                            : result;
+
−  }
+
−  return delta_;
+
−}
+
−
+
−constexpr double TimeDelta::InMillisecondsF() const {
+
−  if (!is_inf()) {
+
−    return static_cast<double>(delta_) / Time::kMicrosecondsPerMillisecond;
+
−  }
+
−  return (delta_ < 0) ? -std::numeric_limits<double>::infinity()
+
−                      : std::numeric_limits<double>::infinity();
+
−}
+
−
+
−constexpr int64_t TimeDelta::InMilliseconds() const {
+
−  if (!is_inf()) {
+
−    return delta_ / Time::kMicrosecondsPerMillisecond;
+
−  }
+
−  return (delta_ < 0) ? std::numeric_limits<int64_t>::min()
+
−                      : std::numeric_limits<int64_t>::max();
+
−}
+
−
+
−constexpr int64_t TimeDelta::InMillisecondsRoundedUp() const {
+
−  if (!is_inf()) {
+
−    const int64_t result = delta_ / Time::kMicrosecondsPerMillisecond;
+
−    // Convert |result| from truncating to ceiling.
+
−    return (delta_ > result * Time::kMicrosecondsPerMillisecond) ? (result + 1)
+
−                                                                 : result;
+
−  }
+
−  return delta_;
+
−}
+
−
+
−constexpr double TimeDelta::InMicrosecondsF() const {
+
−  if (!is_inf()) {
+
−    return static_cast<double>(delta_);
+
−  }
+
−  return (delta_ < 0) ? -std::numeric_limits<double>::infinity()
+
−                      : std::numeric_limits<double>::infinity();
+
−}
+
−
+
−constexpr int64_t TimeDelta::InNanoseconds() const {
+
−  return base::ClampMul(delta_, Time::kNanosecondsPerMicrosecond);
+
−}
+
−
+
−// static
+
−constexpr TimeDelta TimeDelta::Max() {
+
−  return TimeDelta(std::numeric_limits<int64_t>::max());
+
−}
+
−
+
−// static
+
−constexpr TimeDelta TimeDelta::Min() {
+
−  return TimeDelta(std::numeric_limits<int64_t>::min());
+
−}
+
−
+
−// static
+
−constexpr TimeDelta TimeDelta::FiniteMax() {
+
−  return TimeDelta(std::numeric_limits<int64_t>::max() - 1);
+
−}
+
−
+
−// static
+
−constexpr TimeDelta TimeDelta::FiniteMin() {
+
−  return TimeDelta(std::numeric_limits<int64_t>::min() + 1);
+
−}
+
−
+
−// TimeBase functions that must appear below the declarations of Time/TimeDelta
+
−namespace time_internal {
+
−
+
−template <class TimeClass>
+
−constexpr TimeDelta TimeBase<TimeClass>::since_origin() const {
+
−  return Microseconds(us_);
+
−}
+
−
+
−template <class TimeClass>
+
−constexpr TimeDelta TimeBase<TimeClass>::operator-(
+
−    const TimeBase<TimeClass>& other) const {
+
−  return Microseconds(us_ - other.us_);
+
−}
+
−
+
−template <class TimeClass>
+
−constexpr TimeClass TimeBase<TimeClass>::operator+(TimeDelta delta) const {
+
−  return TimeClass((Microseconds(us_) + delta).InMicroseconds());
+
−}
+
−
+
−template <class TimeClass>
+
−constexpr TimeClass TimeBase<TimeClass>::operator-(TimeDelta delta) const {
+
−  return TimeClass((Microseconds(us_) - delta).InMicroseconds());
+
−}
+
−
+
−}  // namespace time_internal
+
−
+
−// Time functions that must appear below the declarations of Time/TimeDelta
+
−
+
−// static
+
−constexpr Time Time::FromTimeT(time_t tt) {
+
−  if (tt == 0)
+
−    return Time();  // Preserve 0 so we can tell it doesn't exist.
+
−  return (tt == std::numeric_limits<time_t>::max())
+
−             ? Max()
+
−             : (UnixEpoch() + Seconds(tt));
+
−}
+
−
+
−constexpr time_t Time::ToTimeT() const {
+
−  if (is_null()) {
+
−    return 0;  // Preserve 0 so we can tell it doesn't exist.
+
−  }
+
−  if (!is_inf()) {
+
−    return saturated_cast<time_t>((*this - UnixEpoch()).InSecondsFloored());
+
−  }
+
−  return (us_ < 0) ? std::numeric_limits<time_t>::min()
+
−                   : std::numeric_limits<time_t>::max();
+
−}
+
−
+
−// static
+
−constexpr Time Time::FromDoubleT(double dt) {
+
−  // Preserve 0 so we can tell it doesn't exist.
+
−  return (dt == 0 || std::isnan(dt)) ? Time() : (UnixEpoch() + Seconds(dt));
+
−}
+
−
+
−constexpr double Time::ToDoubleT() const {
+
−  if (is_null()) {
+
−    return 0;  // Preserve 0 so we can tell it doesn't exist.
+
−  }
+
−  if (!is_inf()) {
+
−    return (*this - UnixEpoch()).InSecondsF();
+
−  }
+
−  return (us_ < 0) ? -std::numeric_limits<double>::infinity()
+
−                   : std::numeric_limits<double>::infinity();
+
−}
+
−
+
−#if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
+
−// static
+
−constexpr Time Time::FromTimeSpec(const timespec& ts) {
+
−  return FromDoubleT(ts.tv_sec +
+
−                     static_cast<double>(ts.tv_nsec) / kNanosecondsPerSecond);
+
−}
+
−#endif
+
−
+
−// static
+
−constexpr Time Time::FromJsTime(double ms_since_epoch) {
+
−  // The epoch is a valid time, so this constructor doesn't interpret 0 as the
+
−  // null time.
+
−  return UnixEpoch() + Milliseconds(ms_since_epoch);
+
−}
+
−
+
−constexpr double Time::ToJsTime() const {
+
−  // Preserve 0 so the invalid result doesn't depend on the platform.
+
−  return is_null() ? 0 : ToJsTimeIgnoringNull();
+
−}
+
−
+
−constexpr double Time::ToJsTimeIgnoringNull() const {
+
−  // Preserve max and min without offset to prevent over/underflow.
+
−  if (!is_inf()) {
+
−    return (*this - UnixEpoch()).InMillisecondsF();
+
−  }
+
−  return (us_ < 0) ? -std::numeric_limits<double>::infinity()
+
−                   : std::numeric_limits<double>::infinity();
+
−}
+
−
+
−constexpr Time Time::FromJavaTime(int64_t ms_since_epoch) {
+
−  return UnixEpoch() + Milliseconds(ms_since_epoch);
+
−}
+
−
+
−constexpr int64_t Time::ToJavaTime() const {
+
−  // Preserve 0 so the invalid result doesn't depend on the platform.
+
−  if (is_null()) {
+
−    return 0;
+
−  }
+
−  if (!is_inf()) {
+
−    return (*this - UnixEpoch()).InMilliseconds();
+
−  }
+
−  return (us_ < 0) ? std::numeric_limits<int64_t>::min()
+
−                   : std::numeric_limits<int64_t>::max();
+
−}
+
−
+
−// For logging use only.
+
−BASE_EXPORT std::ostream& operator<<(std::ostream& os, Time time);
+
−
+
−// TimeTicks ------------------------------------------------------------------
+
−
+
−// Represents monotonically non-decreasing clock time.
+
−class BASE_EXPORT TimeTicks : public time_internal::TimeBase<TimeTicks> {
+
− public:
+
−  // The underlying clock used to generate new TimeTicks.
+
−  enum class Clock {
+
−    FUCHSIA_ZX_CLOCK_MONOTONIC,
+
−    LINUX_CLOCK_MONOTONIC,
+
−    IOS_CF_ABSOLUTE_TIME_MINUS_KERN_BOOTTIME,
+
−    MAC_MACH_ABSOLUTE_TIME,
+
−    WIN_QPC,
+
−    WIN_ROLLOVER_PROTECTED_TIME_GET_TIME
+
−  };
+
−
+
−  constexpr TimeTicks() : TimeBase(0) {}
+
−
+
−  // Platform-dependent tick count representing "right now." When
+
−  // IsHighResolution() returns false, the resolution of the clock could be
+
−  // as coarse as ~15.6ms. Otherwise, the resolution should be no worse than one
+
−  // microsecond.
+
−  static TimeTicks Now();
+
−
+
−  // Returns true if the high resolution clock is working on this system and
+
−  // Now() will return high resolution values. Note that, on systems where the
+
−  // high resolution clock works but is deemed inefficient, the low resolution
+
−  // clock will be used instead.
+
−  [[nodiscard]] static bool IsHighResolution();
+
−
+
−  // Returns true if TimeTicks is consistent across processes, meaning that
+
−  // timestamps taken on different processes can be safely compared with one
+
−  // another. (Note that, even on platforms where this returns true, time values
+
−  // from different threads that are within one tick of each other must be
+
−  // considered to have an ambiguous ordering.)
+
−  [[nodiscard]] static bool IsConsistentAcrossProcesses();
+
−
+
−#if BUILDFLAG(IS_FUCHSIA)
+
−  // Converts between TimeTicks and an ZX_CLOCK_MONOTONIC zx_time_t value.
+
−  static TimeTicks FromZxTime(zx_time_t nanos_since_boot);
+
−  zx_time_t ToZxTime() const;
+
−#endif
+
−
+
−#if BUILDFLAG(IS_WIN)
+
−  // Translates an absolute QPC timestamp into a TimeTicks value. The returned
+
−  // value has the same origin as Now(). Do NOT attempt to use this if
+
−  // IsHighResolution() returns false.
+
−  static TimeTicks FromQPCValue(LONGLONG qpc_value);
+
−#endif
+
−
+
−#if BUILDFLAG(IS_APPLE)
+
−#if BUILDFLAG(ENABLE_MACH_ABSOLUTE_TIME_TICKS)
+
−  static TimeTicks FromMachAbsoluteTime(uint64_t mach_absolute_time);
+
−
+
−  // Sets the current Mach timebase to `timebase`. Returns the old timebase.
+
−  static mach_timebase_info_data_t SetMachTimebaseInfoForTesting(
+
−      mach_timebase_info_data_t timebase);
+
−
+
−#endif  // BUILDFLAG(ENABLE_MACH_ABSOLUTE_TIME_TICKS)
+
−#endif  // BUILDFLAG(IS_APPLE)
+
−
+
−#if BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_CHROMEOS_ASH)
+
−  // Converts to TimeTicks the value obtained from SystemClock.uptimeMillis().
+
−  // Note: this conversion may be non-monotonic in relation to previously
+
−  // obtained TimeTicks::Now() values because of the truncation (to
+
−  // milliseconds) performed by uptimeMillis().
+
−  static TimeTicks FromUptimeMillis(int64_t uptime_millis_value);
+
−
+
−#endif  // BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_CHROMEOS_ASH)
+
−
+
−#if BUILDFLAG(IS_ANDROID)
+
−  // Converts to TimeTicks the value obtained from System.nanoTime(). This
+
−  // conversion will be monotonic in relation to previously obtained
+
−  // TimeTicks::Now() values as the clocks are based on the same posix monotonic
+
−  // clock, with nanoTime() potentially providing higher resolution.
+
−  static TimeTicks FromJavaNanoTime(int64_t nano_time_value);
+
−
+
−  // Truncates the TimeTicks value to the precision of SystemClock#uptimeMillis.
+
−  // Note that the clocks already share the same monotonic clock source.
+
−  jlong ToUptimeMillis() const;
+
−
+
−  // Returns the TimeTicks value as microseconds in the timebase of
+
−  // SystemClock#uptimeMillis.
+
−  // Note that the clocks already share the same monotonic clock source.
+
−  //
+
−  // System.nanoTime() may be used to get sub-millisecond precision in Java code
+
−  // and may be compared against this value as the two share the same clock
+
−  // source (though be sure to convert nanos to micros).
+
−  jlong ToUptimeMicros() const;
+
−
+
−#endif  // BUILDFLAG(IS_ANDROID)
+
−
+
−  // Get an estimate of the TimeTick value at the time of the UnixEpoch. Because
+
−  // Time and TimeTicks respond differently to user-set time and NTP
+
−  // adjustments, this number is only an estimate. Nevertheless, this can be
+
−  // useful when you need to relate the value of TimeTicks to a real time and
+
−  // date. Note: Upon first invocation, this function takes a snapshot of the
+
−  // realtime clock to establish a reference point.  This function will return
+
−  // the same value for the duration of the application, but will be different
+
−  // in future application runs.
+
−  static TimeTicks UnixEpoch();
+
−
+
−  static void SetSharedUnixEpoch(TimeTicks);
+
−
+
−  // Returns |this| snapped to the next tick, given a |tick_phase| and
+
−  // repeating |tick_interval| in both directions. |this| may be before,
+
−  // after, or equal to the |tick_phase|.
+
−  TimeTicks SnappedToNextTick(TimeTicks tick_phase,
+
−                              TimeDelta tick_interval) const;
+
−
+
−  // Returns an enum indicating the underlying clock being used to generate
+
−  // TimeTicks timestamps. This function should only be used for debugging and
+
−  // logging purposes.
+
−  static Clock GetClock();
+
−
+
−  // Converts an integer value representing TimeTicks to a class. This may be
+
−  // used when deserializing a |TimeTicks| structure, using a value known to be
+
−  // compatible. It is not provided as a constructor because the integer type
+
−  // may be unclear from the perspective of a caller.
+
−  //
+
−  // DEPRECATED - Do not use in new code. For deserializing TimeTicks values,
+
−  // prefer TimeTicks + TimeDelta(); however, be aware that the origin is not
+
−  // fixed and may vary. Serializing for persistence is strongly discouraged.
+
−  // http://crbug.com/634507
+
−  static constexpr TimeTicks FromInternalValue(int64_t us) {
+
−    return TimeTicks(us);
+
−  }
+
−
+
− protected:
+
−#if BUILDFLAG(IS_WIN)
+
−  typedef DWORD (*TickFunctionType)(void);
+
−  static TickFunctionType SetMockTickFunction(TickFunctionType ticker);
+
−#endif
+
−
+
− private:
+
−  friend class time_internal::TimeBase<TimeTicks>;
+
−
+
−  // Please use Now() to create a new object. This is for internal use
+
−  // and testing.
+
−  constexpr explicit TimeTicks(int64_t us) : TimeBase(us) {}
+
−};
+
−
+
−// For logging use only.
+
−BASE_EXPORT std::ostream& operator<<(std::ostream& os, TimeTicks time_ticks);
+
−
+
−// LiveTicks ------------------------------------------------------------------
+
−
+
−// Behaves similarly to `TimeTicks` (a monotonically non-decreasing clock time)
+
−// with the main difference being that `LiveTicks` is guaranteed not to advance
+
−// while the system is suspended.
+
−class BASE_EXPORT LiveTicks : public time_internal::TimeBase<LiveTicks> {
+
− public:
+
−  constexpr LiveTicks() : TimeBase(0) {}
+
−  static LiveTicks Now();
+
−
+
− private:
+
−  friend class time_internal::TimeBase<LiveTicks>;
+
−
+
−  // Please use Now() to create a new object. This is for internal use
+
−  // and testing.
+
−  constexpr explicit LiveTicks(int64_t us) : TimeBase(us) {}
+
−};
+
−
+
−// ThreadTicks ----------------------------------------------------------------
+
−
+
−// Represents a clock, specific to a particular thread, than runs only while the
+
−// thread is running.
+
−class BASE_EXPORT ThreadTicks : public time_internal::TimeBase<ThreadTicks> {
+
− public:
+
−  constexpr ThreadTicks() : TimeBase(0) {}
+
−
+
−  // Returns true if ThreadTicks::Now() is supported on this system.
+
−  [[nodiscard]] static bool IsSupported() {
+
−#if (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
+
−    BUILDFLAG(IS_APPLE) || BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_FUCHSIA)
+
−    return true;
+
−#elif BUILDFLAG(IS_WIN)
+
−    return IsSupportedWin();
+
−#else
+
−    return false;
+
−#endif
+
−  }
+
−
+
−  // Waits until the initialization is completed. Needs to be guarded with a
+
−  // call to IsSupported().
+
−  static void WaitUntilInitialized() {
+
−#if BUILDFLAG(IS_WIN)
+
−    WaitUntilInitializedWin();
+
−#endif
+
−  }
+
−
+
−  // Returns thread-specific CPU-time on systems that support this feature.
+
−  // Needs to be guarded with a call to IsSupported(). Use this timer
+
−  // to (approximately) measure how much time the calling thread spent doing
+
−  // actual work vs. being de-scheduled. May return bogus results if the thread
+
−  // migrates to another CPU between two calls. Returns an empty ThreadTicks
+
−  // object until the initialization is completed. If a clock reading is
+
−  // absolutely needed, call WaitUntilInitialized() before this method.
+
−  static ThreadTicks Now();
+
−
+
−#if BUILDFLAG(IS_WIN)
+
−  // Similar to Now() above except this returns thread-specific CPU time for an
+
−  // arbitrary thread. All comments for Now() method above apply apply to this
+
−  // method as well.
+
−  static ThreadTicks GetForThread(const PlatformThreadHandle& thread_handle);
+
−#endif
+
−
+
−  // Converts an integer value representing ThreadTicks to a class. This may be
+
−  // used when deserializing a |ThreadTicks| structure, using a value known to
+
−  // be compatible. It is not provided as a constructor because the integer type
+
−  // may be unclear from the perspective of a caller.
+
−  //
+
−  // DEPRECATED - Do not use in new code. For deserializing ThreadTicks values,
+
−  // prefer ThreadTicks + TimeDelta(); however, be aware that the origin is not
+
−  // fixed and may vary. Serializing for persistence is strongly
+
−  // discouraged. http://crbug.com/634507
+
−  static constexpr ThreadTicks FromInternalValue(int64_t us) {
+
−    return ThreadTicks(us);
+
−  }
+
−
+
− private:
+
−  friend class time_internal::TimeBase<ThreadTicks>;
+
−
+
−  // Please use Now() or GetForThread() to create a new object. This is for
+
−  // internal use and testing.
+
−  constexpr explicit ThreadTicks(int64_t us) : TimeBase(us) {}
+
−
+
−#if BUILDFLAG(IS_WIN)
+
−  [[nodiscard]] static bool IsSupportedWin();
+
−  static void WaitUntilInitializedWin();
+
−#endif
+
−};
+
−
+
−// For logging use only.
+
−BASE_EXPORT std::ostream& operator<<(std::ostream& os, ThreadTicks time_ticks);
+
−
+
−// Returns a string representation of the given time in the IMF-fixdate format
+
−// defined by RFC 7231 (satisfying its HTTP-date format).
+
−BASE_EXPORT std::string TimeFormatHTTP(base::Time time);
+
−
+
−}  // namespace base
+
−
+
−#endif  // BASE_TIME_TIME_H_