Files
scylladb/db_clock.hh
Avi Kivity 1cc6df68c6 db: add a db_clock type
Origin uses the Java clock (milliseconds since unix epoch), provide a
clock emulating this functionality.
2015-01-06 15:26:40 +02:00

35 lines
1.0 KiB
C++

/*
* Copyright (C) 2014 Cloudius Systems, Ltd.
*/
#ifndef DB_CLOCK_HH_
#define DB_CLOCK_HH_
#include <chrono>
#include <cstdint>
// the database clock follows Java - 1ms granularity, 64-bit counter, 1970 epoch
class db_clock {
using base = std::chrono::system_clock;
public:
using rep = int64_t;
using period = std::ratio<1, 1000>; // milliseconds
using duration = std::chrono::duration<rep, period>;
using time_point = std::chrono::time_point<db_clock, duration>;
static constexpr bool is_steady = base::is_steady;
static std::time_t to_time_t(time_point t) {
return std::chrono::duration_cast<std::chrono::seconds>(t.time_since_epoch()).count();
}
static 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() {
auto now_since_epoch = base::now() - base::from_time_t(0);
return time_point(std::chrono::duration_cast<duration>(now_since_epoch));
}
};
#endif /* DB_CLOCK_HH_ */