Files
scylla/gc_clock.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

60 lines
1.9 KiB
C++

/*
* Copyright (C) 2015 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 "clocks-impl.hh"
#include <seastar/core/lowres_clock.hh>
#include <chrono>
#include <experimental/optional>
// FIXME: wraps around in 2038
class gc_clock {
public:
using base = seastar::lowres_system_clock;
using rep = int32_t;
using period = std::ratio<1, 1>; // seconds
using duration = std::chrono::duration<rep, period>;
using time_point = std::chrono::time_point<gc_clock, duration>;
static constexpr auto is_steady = base::is_steady;
static constexpr std::time_t to_time_t(time_point t) {
return std::chrono::duration_cast<std::chrono::seconds>(t.time_since_epoch()).count();
}
static constexpr time_point from_time_t(std::time_t t) {
return time_point(std::chrono::duration_cast<duration>(std::chrono::seconds(t)));
}
static time_point now() {
return time_point(std::chrono::duration_cast<duration>(base::now().time_since_epoch())) + get_clocks_offset();
}
};
using expiry_opt = std::experimental::optional<gc_clock::time_point>;
using ttl_opt = std::experimental::optional<gc_clock::duration>;
// 20 years in seconds
static constexpr gc_clock::duration max_ttl = gc_clock::duration{20 * 365 * 24 * 60 * 60};