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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// QuicTime represents one point in time, stored in microsecond resolution.
// QuicTime is monotonically increasing, even across system clock adjustments.
// The epoch (time 0) of QuicTime is unspecified.
//
// This implementation wraps a int64_t of usec since the epoch. While
// the epoch is the Unix epoch, do not depend on this fact because other
// implementations, like Chrome's, do NOT have the same epoch.
#ifndef QUICHE_QUIC_CORE_QUIC_TIME_H_
#define QUICHE_QUIC_CORE_QUIC_TIME_H_
#include <cmath>
#include <cstdint>
#include <limits>
#include <ostream>
#include <string>
#include "absl/time/time.h"
#include "quiche/quic/platform/api/quic_export.h"
// TODO(vasilvv): replace with ABSL_MUST_USE_RESULT once we're using absl.
#if defined(__clang__)
#define QUIC_TIME_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
#else
#define QUIC_TIME_WARN_UNUSED_RESULT
#endif /* defined(__clang__) */
namespace quic {
class QuicClock;
// A QuicTime is a purely relative time. QuicTime values from different clocks
// cannot be compared to each other. If you need an absolute time, see
// QuicWallTime, below.
class QUIC_EXPORT_PRIVATE QuicTime {
public:
// A QuicTime::Delta represents the signed difference between two points in
// time, stored in microsecond resolution.
class QUIC_EXPORT_PRIVATE Delta {
public:
// Create a object with an offset of 0.
static constexpr Delta Zero() { return Delta(0); }
// Create a object with infinite offset time.
static constexpr Delta Infinite() { return Delta(kQuicInfiniteTimeUs); }
// Converts a number of seconds to a time offset.
static constexpr Delta FromSeconds(int64_t secs) {
return Delta(secs * 1000 * 1000);
}
// Converts a number of milliseconds to a time offset.
static constexpr Delta FromMilliseconds(int64_t ms) {
return Delta(ms * 1000);
}
// Converts a number of microseconds to a time offset.
static constexpr Delta FromMicroseconds(int64_t us) { return Delta(us); }
// Converts from Abseil duration type.
static constexpr Delta FromAbsl(absl::Duration duration) {
if (ABSL_PREDICT_FALSE(duration == absl::InfiniteDuration())) {
return Infinite();
}
return Delta(absl::ToInt64Microseconds(duration));
}
// Converts the time offset to a rounded number of seconds.
constexpr int64_t ToSeconds() const { return time_offset_ / 1000 / 1000; }
// Converts the time offset to a rounded number of milliseconds.
constexpr int64_t ToMilliseconds() const { return time_offset_ / 1000; }
// Converts the time offset to a rounded number of microseconds.
constexpr int64_t ToMicroseconds() const { return time_offset_; }
// Converts the time offset to an Abseil duration.
constexpr absl::Duration ToAbsl() {
if (ABSL_PREDICT_FALSE(IsInfinite())) {
return absl::InfiniteDuration();
}
return absl::Microseconds(time_offset_);
}
constexpr bool IsZero() const { return time_offset_ == 0; }
constexpr bool IsInfinite() const {
return time_offset_ == kQuicInfiniteTimeUs;
}
std::string ToDebuggingValue() const;
private:
friend inline bool operator==(QuicTime::Delta lhs, QuicTime::Delta rhs);
friend inline bool operator<(QuicTime::Delta lhs, QuicTime::Delta rhs);
friend inline QuicTime::Delta operator<<(QuicTime::Delta lhs, size_t rhs);
friend inline QuicTime::Delta operator>>(QuicTime::Delta lhs, size_t rhs);
friend inline constexpr QuicTime::Delta operator+(QuicTime::Delta lhs,
QuicTime::Delta rhs);
friend inline constexpr QuicTime::Delta operator-(QuicTime::Delta lhs,
QuicTime::Delta rhs);
friend inline constexpr QuicTime::Delta operator*(QuicTime::Delta lhs,
int rhs);
// Not constexpr since std::llround() is not constexpr.
friend inline QuicTime::Delta operator*(QuicTime::Delta lhs, double rhs);
friend inline QuicTime operator+(QuicTime lhs, QuicTime::Delta rhs);
friend inline QuicTime operator-(QuicTime lhs, QuicTime::Delta rhs);
friend inline QuicTime::Delta operator-(QuicTime lhs, QuicTime rhs);
static const int64_t kQuicInfiniteTimeUs =
std::numeric_limits<int64_t>::max();
explicit constexpr Delta(int64_t time_offset) : time_offset_(time_offset) {}
int64_t time_offset_;
friend class QuicTime;
};
// Creates a new QuicTime with an internal value of 0. IsInitialized()
// will return false for these times.
static constexpr QuicTime Zero() { return QuicTime(0); }
// Creates a new QuicTime with an infinite time.
static constexpr QuicTime Infinite() {
return QuicTime(Delta::kQuicInfiniteTimeUs);
}
QuicTime(const QuicTime& other) = default;
QuicTime& operator=(const QuicTime& other) {
time_ = other.time_;
return *this;
}
// Produce the internal value to be used when logging. This value
// represents the number of microseconds since some epoch. It may
// be the UNIX epoch on some platforms. On others, it may
// be a CPU ticks based value.
int64_t ToDebuggingValue() const { return time_; }
bool IsInitialized() const { return 0 != time_; }
private:
friend class QuicClock;
friend inline bool operator==(QuicTime lhs, QuicTime rhs);
friend inline bool operator<(QuicTime lhs, QuicTime rhs);
friend inline QuicTime operator+(QuicTime lhs, QuicTime::Delta rhs);
friend inline QuicTime operator-(QuicTime lhs, QuicTime::Delta rhs);
friend inline QuicTime::Delta operator-(QuicTime lhs, QuicTime rhs);
explicit constexpr QuicTime(int64_t time) : time_(time) {}
int64_t time_;
};
// A QuicWallTime represents an absolute time that is globally consistent. In
// practice, clock-skew means that comparing values from different machines
// requires some flexibility.
class QUIC_EXPORT_PRIVATE QuicWallTime {
public:
// FromUNIXSeconds constructs a QuicWallTime from a count of the seconds
// since the UNIX epoch.
static constexpr QuicWallTime FromUNIXSeconds(uint64_t seconds) {
return QuicWallTime(seconds * 1000000);
}
static constexpr QuicWallTime FromUNIXMicroseconds(uint64_t microseconds) {
return QuicWallTime(microseconds);
}
// Zero returns a QuicWallTime set to zero. IsZero will return true for this
// value.
static constexpr QuicWallTime Zero() { return QuicWallTime(0); }
// Returns the number of seconds since the UNIX epoch.
uint64_t ToUNIXSeconds() const;
// Returns the number of microseconds since the UNIX epoch.
uint64_t ToUNIXMicroseconds() const;
bool IsAfter(QuicWallTime other) const;
bool IsBefore(QuicWallTime other) const;
// IsZero returns true if this object is the result of calling |Zero|.
bool IsZero() const;
// AbsoluteDifference returns the absolute value of the time difference
// between |this| and |other|.
QuicTime::Delta AbsoluteDifference(QuicWallTime other) const;
// Add returns a new QuicWallTime that represents the time of |this| plus
// |delta|.
QUIC_TIME_WARN_UNUSED_RESULT QuicWallTime Add(QuicTime::Delta delta) const;
// Subtract returns a new QuicWallTime that represents the time of |this|
// minus |delta|.
QUIC_TIME_WARN_UNUSED_RESULT QuicWallTime
Subtract(QuicTime::Delta delta) const;
bool operator==(const QuicWallTime& other) const {
return microseconds_ == other.microseconds_;
}
QuicTime::Delta operator-(const QuicWallTime& rhs) const {
return QuicTime::Delta::FromMicroseconds(microseconds_ - rhs.microseconds_);
}
private:
explicit constexpr QuicWallTime(uint64_t microseconds)
: microseconds_(microseconds) {}
uint64_t microseconds_;
};
// Non-member relational operators for QuicTime::Delta.
inline bool operator==(QuicTime::Delta lhs, QuicTime::Delta rhs) {
return lhs.time_offset_ == rhs.time_offset_;
}
inline bool operator!=(QuicTime::Delta lhs, QuicTime::Delta rhs) {
return !(lhs == rhs);
}
inline bool operator<(QuicTime::Delta lhs, QuicTime::Delta rhs) {
return lhs.time_offset_ < rhs.time_offset_;
}
inline bool operator>(QuicTime::Delta lhs, QuicTime::Delta rhs) {
return rhs < lhs;
}
inline bool operator<=(QuicTime::Delta lhs, QuicTime::Delta rhs) {
return !(rhs < lhs);
}
inline bool operator>=(QuicTime::Delta lhs, QuicTime::Delta rhs) {
return !(lhs < rhs);
}
inline QuicTime::Delta operator<<(QuicTime::Delta lhs, size_t rhs) {
return QuicTime::Delta(lhs.time_offset_ << rhs);
}
inline QuicTime::Delta operator>>(QuicTime::Delta lhs, size_t rhs) {
return QuicTime::Delta(lhs.time_offset_ >> rhs);
}
// Non-member relational operators for QuicTime.
inline bool operator==(QuicTime lhs, QuicTime rhs) {
return lhs.time_ == rhs.time_;
}
inline bool operator!=(QuicTime lhs, QuicTime rhs) { return !(lhs == rhs); }
inline bool operator<(QuicTime lhs, QuicTime rhs) {
return lhs.time_ < rhs.time_;
}
inline bool operator>(QuicTime lhs, QuicTime rhs) { return rhs < lhs; }
inline bool operator<=(QuicTime lhs, QuicTime rhs) { return !(rhs < lhs); }
inline bool operator>=(QuicTime lhs, QuicTime rhs) { return !(lhs < rhs); }
// Override stream output operator for gtest or QUICHE_CHECK macros.
inline std::ostream& operator<<(std::ostream& output, const QuicTime t) {
output << t.ToDebuggingValue();
return output;
}
// Non-member arithmetic operators for QuicTime::Delta.
inline constexpr QuicTime::Delta operator+(QuicTime::Delta lhs,
QuicTime::Delta rhs) {
return QuicTime::Delta(lhs.time_offset_ + rhs.time_offset_);
}
inline constexpr QuicTime::Delta operator-(QuicTime::Delta lhs,
QuicTime::Delta rhs) {
return QuicTime::Delta(lhs.time_offset_ - rhs.time_offset_);
}
inline constexpr QuicTime::Delta operator*(QuicTime::Delta lhs, int rhs) {
return QuicTime::Delta(lhs.time_offset_ * rhs);
}
inline QuicTime::Delta operator*(QuicTime::Delta lhs, double rhs) {
return QuicTime::Delta(static_cast<int64_t>(
std::llround(static_cast<double>(lhs.time_offset_) * rhs)));
}
inline QuicTime::Delta operator*(int lhs, QuicTime::Delta rhs) {
return rhs * lhs;
}
inline QuicTime::Delta operator*(double lhs, QuicTime::Delta rhs) {
return rhs * lhs;
}
// Non-member arithmetic operators for QuicTime and QuicTime::Delta.
inline QuicTime operator+(QuicTime lhs, QuicTime::Delta rhs) {
return QuicTime(lhs.time_ + rhs.time_offset_);
}
inline QuicTime operator-(QuicTime lhs, QuicTime::Delta rhs) {
return QuicTime(lhs.time_ - rhs.time_offset_);
}
inline QuicTime::Delta operator-(QuicTime lhs, QuicTime rhs) {
return QuicTime::Delta(lhs.time_ - rhs.time_);
}
// Override stream output operator for gtest.
inline std::ostream& operator<<(std::ostream& output,
const QuicTime::Delta delta) {
output << delta.ToDebuggingValue();
return output;
}
} // namespace quic
#endif // QUICHE_QUIC_CORE_QUIC_TIME_H_