Files
scylladb/clocks-impl.hh
Jesse Haber-Kucharsky e045dddae8 Move common clock implementation helpers
This change fixes the dependencies between the clock implementation headers. All
the clocks share the common clock offset, but are otherwise independent (though
the `db_clock` does depend on `gc_clock` for time point conversions).
2017-06-23 11:35:35 -04:00

50 lines
1.6 KiB
C++

/*
* Copyright (C) 2017 ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <algorithm>
#include <atomic>
#include <chrono>
#include <cstdint>
extern std::atomic<int64_t> clocks_offset;
template<typename Duration>
static inline void forward_jump_clocks(Duration delta)
{
auto d = std::chrono::duration_cast<std::chrono::seconds>(delta).count();
clocks_offset.fetch_add(d, std::memory_order_relaxed);
}
static inline std::chrono::seconds get_clocks_offset()
{
auto off = clocks_offset.load(std::memory_order_relaxed);
return std::chrono::seconds(off);
}
// Returns a time point which is earlier from t by d, or minimum time point if it cannot be represented.
template<typename Clock, typename Duration, typename Rep, typename Period>
inline
auto saturating_subtract(std::chrono::time_point<Clock, Duration> t, std::chrono::duration<Rep, Period> d) -> decltype(t) {
return std::max(t, decltype(t)::min() + d) - d;
}