deps/v8/src/base/platform/time.h
// Copyright 2013 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_BASE_PLATFORM_TIME_H_
#define V8_BASE_PLATFORM_TIME_H_
#include <time.h>
#include <limits>
#include "src/base/macros.h"
// Forward declarations.
extern "C" {
struct _FILETIME;
struct mach_timespec;
struct timespec;
struct timeval;
}
namespace v8 {
namespace base {
class Time;
class TimeTicks;
// -----------------------------------------------------------------------------
// TimeDelta
//
// This class represents a duration of time, internally represented in
// microseonds.
class TimeDelta V8_FINAL {
public:
TimeDelta() : delta_(0) {}
// Converts units of time to TimeDeltas.
static TimeDelta FromDays(int days);
static TimeDelta FromHours(int hours);
static TimeDelta FromMinutes(int minutes);
static TimeDelta FromSeconds(int64_t seconds);
static TimeDelta FromMilliseconds(int64_t milliseconds);
static TimeDelta FromMicroseconds(int64_t microseconds) {
return TimeDelta(microseconds);
}
static TimeDelta FromNanoseconds(int64_t nanoseconds);
// Returns the time delta in some unit. The F versions return a floating
// point value, the "regular" versions return a rounded-down value.
//
// InMillisecondsRoundedUp() instead returns an integer that is rounded up
// to the next full millisecond.
int InDays() const;
int InHours() const;
int InMinutes() const;
double InSecondsF() const;
int64_t InSeconds() const;
double InMillisecondsF() const;
int64_t InMilliseconds() const;
int64_t InMillisecondsRoundedUp() const;
int64_t InMicroseconds() const { return delta_; }
int64_t InNanoseconds() const;
// Converts to/from Mach time specs.
static TimeDelta FromMachTimespec(struct mach_timespec ts);
struct mach_timespec ToMachTimespec() const;
// Converts to/from POSIX time specs.
static TimeDelta FromTimespec(struct timespec ts);
struct timespec ToTimespec() const;
TimeDelta& operator=(const TimeDelta& other) {
delta_ = other.delta_;
return *this;
}
// Computations with other deltas.
TimeDelta operator+(const TimeDelta& other) const {
return TimeDelta(delta_ + other.delta_);
}
TimeDelta operator-(const TimeDelta& other) const {
return TimeDelta(delta_ - other.delta_);
}
TimeDelta& operator+=(const TimeDelta& other) {
delta_ += other.delta_;
return *this;
}
TimeDelta& operator-=(const TimeDelta& other) {
delta_ -= other.delta_;
return *this;
}
TimeDelta operator-() const {
return TimeDelta(-delta_);
}
double TimesOf(const TimeDelta& other) const {
return static_cast<double>(delta_) / static_cast<double>(other.delta_);
}
double PercentOf(const TimeDelta& other) const {
return TimesOf(other) * 100.0;
}
// Computations with ints, note that we only allow multiplicative operations
// with ints, and additive operations with other deltas.
TimeDelta operator*(int64_t a) const {
return TimeDelta(delta_ * a);
}
TimeDelta operator/(int64_t a) const {
return TimeDelta(delta_ / a);
}
TimeDelta& operator*=(int64_t a) {
delta_ *= a;
return *this;
}
TimeDelta& operator/=(int64_t a) {
delta_ /= a;
return *this;
}
int64_t operator/(const TimeDelta& other) const {
return delta_ / other.delta_;
}
// Comparison operators.
bool operator==(const TimeDelta& other) const {
return delta_ == other.delta_;
}
bool operator!=(const TimeDelta& other) const {
return delta_ != other.delta_;
}
bool operator<(const TimeDelta& other) const {
return delta_ < other.delta_;
}
bool operator<=(const TimeDelta& other) const {
return delta_ <= other.delta_;
}
bool operator>(const TimeDelta& other) const {
return delta_ > other.delta_;
}
bool operator>=(const TimeDelta& other) const {
return delta_ >= other.delta_;
}
private:
// Constructs a delta given the duration in microseconds. This is private
// to avoid confusion by callers with an integer constructor. Use
// FromSeconds, FromMilliseconds, etc. instead.
explicit TimeDelta(int64_t delta) : delta_(delta) {}
// Delta in microseconds.
int64_t delta_;
};
// -----------------------------------------------------------------------------
// Time
//
// This class represents an absolute point in time, internally represented as
// microseconds (s/1,000,000) since 00:00:00 UTC, January 1, 1970.
class Time V8_FINAL {
public:
static const int64_t kMillisecondsPerSecond = 1000;
static const int64_t kMicrosecondsPerMillisecond = 1000;
static const int64_t kMicrosecondsPerSecond = kMicrosecondsPerMillisecond *
kMillisecondsPerSecond;
static const int64_t kMicrosecondsPerMinute = kMicrosecondsPerSecond * 60;
static const int64_t kMicrosecondsPerHour = kMicrosecondsPerMinute * 60;
static const int64_t kMicrosecondsPerDay = kMicrosecondsPerHour * 24;
static const int64_t kMicrosecondsPerWeek = kMicrosecondsPerDay * 7;
static const int64_t kNanosecondsPerMicrosecond = 1000;
static const int64_t kNanosecondsPerSecond = kNanosecondsPerMicrosecond *
kMicrosecondsPerSecond;
// Contains the NULL time. Use Time::Now() to get the current time.
Time() : us_(0) {}
// Returns true if the time object has not been initialized.
bool IsNull() const { return us_ == 0; }
// Returns true if the time object is the maximum time.
bool IsMax() const { return us_ == std::numeric_limits<int64_t>::max(); }
// 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();
// Returns the time for epoch in Unix-like system (Jan 1, 1970).
static Time UnixEpoch() { return Time(0); }
// Returns the maximum time, which should be greater than any reasonable time
// with which we might compare it.
static Time Max() { return Time(std::numeric_limits<int64_t>::max()); }
// Converts to/from internal values. The meaning of the "internal value" is
// completely up to the implementation, so it should be treated as opaque.
static Time FromInternalValue(int64_t value) {
return Time(value);
}
int64_t ToInternalValue() const {
return us_;
}
// Converts to/from POSIX time specs.
static Time FromTimespec(struct timespec ts);
struct timespec ToTimespec() const;
// Converts to/from POSIX time values.
static Time FromTimeval(struct timeval tv);
struct timeval ToTimeval() const;
// Converts to/from Windows file times.
static Time FromFiletime(struct _FILETIME ft);
struct _FILETIME ToFiletime() const;
// Converts to/from the Javascript convention for times, a number of
// milliseconds since the epoch:
static Time FromJsTime(double ms_since_epoch);
double ToJsTime() const;
Time& operator=(const Time& other) {
us_ = other.us_;
return *this;
}
// Compute the difference between two times.
TimeDelta operator-(const Time& other) const {
return TimeDelta::FromMicroseconds(us_ - other.us_);
}
// Modify by some time delta.
Time& operator+=(const TimeDelta& delta) {
us_ += delta.InMicroseconds();
return *this;
}
Time& operator-=(const TimeDelta& delta) {
us_ -= delta.InMicroseconds();
return *this;
}
// Return a new time modified by some delta.
Time operator+(const TimeDelta& delta) const {
return Time(us_ + delta.InMicroseconds());
}
Time operator-(const TimeDelta& delta) const {
return Time(us_ - delta.InMicroseconds());
}
// Comparison operators
bool operator==(const Time& other) const {
return us_ == other.us_;
}
bool operator!=(const Time& other) const {
return us_ != other.us_;
}
bool operator<(const Time& other) const {
return us_ < other.us_;
}
bool operator<=(const Time& other) const {
return us_ <= other.us_;
}
bool operator>(const Time& other) const {
return us_ > other.us_;
}
bool operator>=(const Time& other) const {
return us_ >= other.us_;
}
private:
explicit Time(int64_t us) : us_(us) {}
// Time in microseconds in UTC.
int64_t us_;
};
inline Time operator+(const TimeDelta& delta, const Time& time) {
return time + delta;
}
// -----------------------------------------------------------------------------
// TimeTicks
//
// This class represents an abstract time that is most of the time incrementing
// for use in measuring time durations. It is internally represented in
// microseconds. It can not be converted to a human-readable time, but is
// guaranteed not to decrease (if the user changes the computer clock,
// Time::Now() may actually decrease or jump). But note that TimeTicks may
// "stand still", for example if the computer suspended.
class TimeTicks V8_FINAL {
public:
TimeTicks() : ticks_(0) {}
// Platform-dependent tick count representing "right now."
// The resolution of this clock is ~1-15ms. Resolution varies depending
// on hardware/operating system configuration.
// This method never returns a null TimeTicks.
static TimeTicks Now();
// Returns a platform-dependent high-resolution tick count. Implementation
// is hardware dependent and may or may not return sub-millisecond
// resolution. THIS CALL IS GENERALLY MUCH MORE EXPENSIVE THAN Now() AND
// SHOULD ONLY BE USED WHEN IT IS REALLY NEEDED.
// This method never returns a null TimeTicks.
static TimeTicks HighResolutionNow();
// Returns true if the high-resolution clock is working on this system.
static bool IsHighResolutionClockWorking();
// Returns Linux kernel timestamp for generating profiler events. This method
// returns null TimeTicks if the kernel cannot provide the timestamps (e.g.,
// on non-Linux OS or if the kernel module for timestamps is not loaded).
static TimeTicks KernelTimestampNow();
static bool KernelTimestampAvailable();
// Returns true if this object has not been initialized.
bool IsNull() const { return ticks_ == 0; }
// Converts to/from internal values. The meaning of the "internal value" is
// completely up to the implementation, so it should be treated as opaque.
static TimeTicks FromInternalValue(int64_t value) {
return TimeTicks(value);
}
int64_t ToInternalValue() const {
return ticks_;
}
TimeTicks& operator=(const TimeTicks other) {
ticks_ = other.ticks_;
return *this;
}
// Compute the difference between two times.
TimeDelta operator-(const TimeTicks other) const {
return TimeDelta::FromMicroseconds(ticks_ - other.ticks_);
}
// Modify by some time delta.
TimeTicks& operator+=(const TimeDelta& delta) {
ticks_ += delta.InMicroseconds();
return *this;
}
TimeTicks& operator-=(const TimeDelta& delta) {
ticks_ -= delta.InMicroseconds();
return *this;
}
// Return a new TimeTicks modified by some delta.
TimeTicks operator+(const TimeDelta& delta) const {
return TimeTicks(ticks_ + delta.InMicroseconds());
}
TimeTicks operator-(const TimeDelta& delta) const {
return TimeTicks(ticks_ - delta.InMicroseconds());
}
// Comparison operators
bool operator==(const TimeTicks& other) const {
return ticks_ == other.ticks_;
}
bool operator!=(const TimeTicks& other) const {
return ticks_ != other.ticks_;
}
bool operator<(const TimeTicks& other) const {
return ticks_ < other.ticks_;
}
bool operator<=(const TimeTicks& other) const {
return ticks_ <= other.ticks_;
}
bool operator>(const TimeTicks& other) const {
return ticks_ > other.ticks_;
}
bool operator>=(const TimeTicks& other) const {
return ticks_ >= other.ticks_;
}
private:
// Please use Now() to create a new object. This is for internal use
// and testing. Ticks is in microseconds.
explicit TimeTicks(int64_t ticks) : ticks_(ticks) {}
// Tick count in microseconds.
int64_t ticks_;
};
inline TimeTicks operator+(const TimeDelta& delta, const TimeTicks& ticks) {
return ticks + delta;
}
} } // namespace v8::base
#endif // V8_BASE_PLATFORM_TIME_H_