time.c

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/* -*- C -*- */
/*
 * Copyright (c) 2012-2020 Seagate Technology LLC and/or its Affiliates
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * For any questions about this software or licensing,
 * please email opensource@seagate.com or cortx-questions@seagate.com.
 *
 */


#define M0_TRACE_SUBSYSTEM M0_TRACE_SUBSYS_LIB
#include "lib/trace.h"

#include "lib/time.h"
#include "lib/time_internal.h" /* m0_clock_gettime_wrapper */
#include "lib/misc.h"          /* M0_EXPORTED */

m0_time_t m0_time(uint64_t secs, long ns)
{
        return M0_MKTIME(secs, ns);
}
M0_EXPORTED(m0_time);

m0_time_t m0_time_add(const m0_time_t t1, const m0_time_t t2)
{
        m0_time_t res;

        M0_PRE(M0_TIME_NEVER >= t1);
        M0_PRE(M0_TIME_NEVER >= t2);

        if (t1 == M0_TIME_NEVER || t2 == M0_TIME_NEVER)
                res = M0_TIME_NEVER;
        else
                res = t1 + t2;

        M0_POST(res >= t1);
        M0_POST(res >= t2);
        return res;
}
M0_EXPORTED(m0_time_add);

m0_time_t m0_time_sub(const m0_time_t t1, const m0_time_t t2)
{
        m0_time_t res;
        M0_PRE(M0_TIME_NEVER >= t1);
        M0_PRE(t2 < M0_TIME_NEVER);
        M0_ASSERT_INFO(t1 >= t2,
                       "t1="TIME_F" t2="TIME_F, TIME_P(t1), TIME_P(t2));

        if (t1 == M0_TIME_NEVER)
                res = M0_TIME_NEVER;
        else
                res = t1 - t2;

        M0_POST(t1 >= res);
        return res;
}
M0_EXPORTED(m0_time_sub);

uint64_t m0_time_seconds(const m0_time_t time)
{
        return time / M0_TIME_ONE_SECOND;
}
M0_EXPORTED(m0_time_seconds);

uint64_t m0_time_nanoseconds(const m0_time_t time)
{

        return time % M0_TIME_ONE_SECOND;
}
M0_EXPORTED(m0_time_nanoseconds);

m0_time_t m0_time_from_now(uint64_t secs, long ns)
{
        return m0_time_now() + m0_time(secs, ns);
}
M0_EXPORTED(m0_time_from_now);

bool m0_time_is_in_past(m0_time_t t)
{
        return t < m0_time_now();
}

const m0_time_t M0_TIME_IMMEDIATELY = 0;
const m0_time_t M0_TIME_NEVER       = ~0ULL;
M0_EXPORTED(M0_TIME_IMMEDIATELY);
M0_EXPORTED(M0_TIME_NEVER);

const enum CLOCK_SOURCES M0_CLOCK_SOURCE = M0_CLOCK_SOURCE_REALTIME_MONOTONIC;
m0_time_t                m0_time_monotonic_offset;

M0_INTERNAL int m0_time_init(void)
{
        m0_time_t realtime;
        m0_time_t monotonic;

        if (M0_CLOCK_SOURCE == M0_CLOCK_SOURCE_REALTIME_MONOTONIC) {
                monotonic = m0_clock_gettime_wrapper(M0_CLOCK_SOURCE_MONOTONIC);
                realtime  = m0_clock_gettime_wrapper(M0_CLOCK_SOURCE_REALTIME);
                m0_time_monotonic_offset = realtime - monotonic;
                if (m0_time_monotonic_offset == 0)
                        m0_time_monotonic_offset = 1;
        }
        return 0;
} M0_EXPORTED(m0_time_init);

M0_INTERNAL void m0_time_fini(void)
{
} M0_EXPORTED(m0_time_fini);

m0_time_t m0_time_now(void)
{
        m0_time_t      result;

        switch (M0_CLOCK_SOURCE) {
        case M0_CLOCK_SOURCE_REALTIME_MONOTONIC:
                M0_PRE(m0_time_monotonic_offset != 0);
                result = m0_clock_gettime_wrapper(M0_CLOCK_SOURCE_MONOTONIC) +
                         m0_time_monotonic_offset;
                break;
        case M0_CLOCK_SOURCE_GTOD:
                result = m0_clock_gettimeofday_wrapper();
                break;
        case M0_CLOCK_SOURCE_REALTIME:
        case M0_CLOCK_SOURCE_MONOTONIC:
        case M0_CLOCK_SOURCE_MONOTONIC_RAW:
                result = m0_clock_gettime_wrapper(M0_CLOCK_SOURCE);
                break;
        default:
                M0_IMPOSSIBLE("Unknown clock source");
                result = M0_TIME_NEVER;
        };
        return result;
}
M0_EXPORTED(m0_time_now);

M0_INTERNAL m0_time_t m0_time_to_realtime(m0_time_t abs_time)
{
        m0_time_t source_time;
        m0_time_t realtime;
        m0_time_t monotonic;

        if (abs_time != M0_TIME_NEVER && abs_time != 0) {
                switch (M0_CLOCK_SOURCE) {
                case M0_CLOCK_SOURCE_MONOTONIC:
                case M0_CLOCK_SOURCE_MONOTONIC_RAW:
                        source_time = m0_clock_gettime_wrapper(M0_CLOCK_SOURCE);
                        realtime    =
                             m0_clock_gettime_wrapper(M0_CLOCK_SOURCE_REALTIME);
                        abs_time   += realtime - source_time;
                        break;
                case M0_CLOCK_SOURCE_REALTIME_MONOTONIC:
                        monotonic =
                            m0_clock_gettime_wrapper(M0_CLOCK_SOURCE_MONOTONIC);
                        realtime  =
                            m0_clock_gettime_wrapper(M0_CLOCK_SOURCE_REALTIME);
                        /* get monotonic time */
                        abs_time -= m0_time_monotonic_offset;
                        /* add offset for realtime */
                        abs_time += realtime - monotonic;
                        /* It will mitigate time jumps between call
                         * to m0_time_now() and call to this function. */
                        break;
                case M0_CLOCK_SOURCE_GTOD:
                case M0_CLOCK_SOURCE_REALTIME:
                        break;
                default:
                        M0_IMPOSSIBLE("Unknown clock source");
                        abs_time = 0;
                }
        }
        return abs_time;
} M0_EXPORTED(m0_time_to_realtime);

/*
 *  Local variables:
 *  c-indentation-style: "K&R"
 *  c-basic-offset: 8
 *  tab-width: 8
 *  fill-column: 80
 *  scroll-step: 1
 *  End:
 */