src/utils/cond.c

/*
    Copyright (c) 2012 250bpm s.r.o.

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom
    the Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    IN THE SOFTWARE.
*/

#include "cond.h"
#include "fast.h"
#include "aio.h"
#include "err.h"

#ifdef NN_HAVE_WINDOWS

void nn_cond_init (struct nn_cond *self)
{
    InitializeConditionVariable (&self->cond);
    self->infinite = 1;
    nn_clock_init (&self->clock);
}

void nn_cond_term (struct nn_cond *self)
{
    nn_clock_term (&self->clock);

    /*  It seems that on Windows there's no need to terminate
        the condition variable. */
}

void nn_cond_set_timeout (struct nn_cond *self, int timeout)
{
    /*  Infinite timeout. */
    if (timeout < 0) {
        self->infinite = 1;
        return;
    }

    /*  Finite timeout. */
    self->infinite = 0;
    self->timeout = nn_clock_now (&self->clock) + timeout;
}

int nn_cond_wait (struct nn_cond *self, struct nn_mutex *mutex)
{
    uint64_t timeout;
    BOOL brc;

    if (self->infinite)
        timeout = INFINITE;
    else {
        timeout = nn_clock_now (&self->clock);
        if (timeout >= self->timeout)
            timeout = 0;
        else
            timeout = self->timeout - timeout;
    }

    brc = SleepConditionVariableCS (&self->cond, &mutex->mutex,
        (DWORD) timeout);
    if (nn_slow (!brc)) {
        if (GetLastError () == ERROR_TIMEOUT)
            return -ETIMEDOUT;
        win_assert (0);
    }

    return 0;
}

void nn_cond_post (struct nn_cond *self)
{
    WakeConditionVariable (&self->cond);
}

#else

#include <stdint.h>

void nn_cond_init (struct nn_cond *self)
{
    int rc;
    pthread_condattr_t attr;

    rc = pthread_condattr_init (&attr);
    errnum_assert (rc == 0, rc);
#if defined NN_HAVE_OSX
#elif defined NN_HAVE_CLOCK_MONOTONIC
    rc = pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
    errnum_assert (rc == 0, rc);
#else
    rc = pthread_condattr_setclock (&attr, CLOCK_REALTIME);
    errnum_assert (rc == 0, rc);
#endif
    rc = pthread_cond_init (&self->cond, &attr);
    errnum_assert (rc == 0, rc);
    rc = pthread_condattr_destroy (&attr);
    errnum_assert (rc == 0, rc);
    self->infinite = 1;
}

void nn_cond_term (struct nn_cond *self)
{
    int rc;

    rc = pthread_cond_destroy (&self->cond);
    errnum_assert (rc == 0, rc);
}

void nn_cond_set_timeout (struct nn_cond *self, int timeout)
{
    int rc;
#if defined NN_HAVE_OSX
    struct timeval tv;
#endif

    /*  Infinite timeout. */
    if (timeout < 0) {
        self->infinite = 1;
        return;
    }

    /*  Finite timeout. Get current time and add the specified interval. */
    self->infinite = 0;

    /*  On OSX the gettimeofday-based clock is hard-wired to the condition
        variable. There's no way to use different clock. */
#if defined NN_HAVE_OSX
    gettimeofday(&tv, NULL);
    TIMEVAL_TO_TIMESPEC(&tv, &self->timeout);

    /*  On platforms that provide monotonic clock, use it. That way we avoid
        problems when system time is adjusted. */
#elif defined NN_HAVE_CLOCK_MONOTONIC
    rc = clock_gettime (CLOCK_MONOTONIC, &self->timeout);
    errno_assert (rc == 0);

    /*  As a last resort use CLOCK_REALTIME. POSIX requires that this realtime
        clock should be available on any system. */
#else
    rc = clock_gettime (CLOCK_REALTIME, &self->timeout);
    errno_assert (rc == 0);
#endif
    self->timeout.tv_sec += timeout / 1000;
    self->timeout.tv_nsec += (timeout % 1000) * 1000000;
    if (self->timeout.tv_nsec >= 1000000000) {
        ++self->timeout.tv_sec;
        self->timeout.tv_nsec -= 1000000000;
    }
}

int nn_cond_wait (struct nn_cond *self, struct nn_mutex *mutex)
{
    int rc;
    struct timespec ts;

    if (self->infinite) {
        rc = pthread_cond_wait (&self->cond, &mutex->mutex);
        errnum_assert (rc == 0, rc);
    }
    else {
        rc = pthread_cond_timedwait (&self->cond, &mutex->mutex,
            &self->timeout);
        if (rc == ETIMEDOUT)
            return -ETIMEDOUT;
        errnum_assert (rc == 0, rc);
    }

    return 0;
}

void nn_cond_post (struct nn_cond *self)
{
    int rc;

    rc = pthread_cond_signal (&self->cond);
    errnum_assert (rc == 0, rc);
}

#endif