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tdlib-fork/tdutils/td/utils/Time.h

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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2019
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#pragma once
#include "td/utils/common.h"
#include "td/utils/port/Clocks.h"
namespace td {
class Time {
public:
static double now();
static double now_cached() {
// Temporary(?) use now in now_cached
// Problem:
// thread A: check that now() > timestamp and notifies thread B
// thread B: must see that now() > timestamp()
//
// now() and now_cached() must be monotonic
//
// if a=now[_cached]() happens before b=now[_cached] than
// a <= b
//
// As an alternative we may say that now_cached is a thread local copy of now
return now();
}
};
inline void relax_timeout_at(double *timeout, double new_timeout) {
if (new_timeout == 0) {
return;
}
if (*timeout == 0 || new_timeout < *timeout) {
*timeout = new_timeout;
}
}
class Timestamp {
public:
Timestamp() = default;
static Timestamp never() {
return Timestamp{};
}
static Timestamp now() {
return Timestamp{Time::now()};
}
static Timestamp now_cached() {
return Timestamp{Time::now_cached()};
}
static Timestamp at(double timeout) {
return Timestamp{timeout};
}
static Timestamp at_unix(double timeout) {
return Timestamp{timeout - Clocks::system() + Time::now()};
}
static Timestamp in(double timeout) {
return Timestamp{Time::now_cached() + timeout};
}
bool is_in_past() const {
return at_ <= Time::now_cached();
}
explicit operator bool() const {
return at_ > 0;
}
double at() const {
return at_;
}
double at_unix() const {
return at_ + Clocks::system() - Time::now();
}
double in() const {
return at_ - Time::now_cached();
}
void relax(const Timestamp &timeout) {
if (!timeout) {
return;
}
if (!*this || at_ > timeout.at_) {
at_ = timeout.at_;
}
}
friend bool operator==(Timestamp a, Timestamp b);
private:
double at_{0};
explicit Timestamp(double timeout) : at_(timeout) {
}
};
template <class StorerT>
void store(const Timestamp &timestamp, StorerT &storer) {
storer.store_binary(timestamp.at() - Time::now() + Clocks::system());
}
template <class ParserT>
void parse(Timestamp &timestamp, ParserT &parser) {
timestamp = Timestamp::in(parser.fetch_double() - Clocks::system());
}
} // namespace td