source: vscpl/src/hu/varadiistvan/scpl/io/_posix/WaitableEvent.cc@ 21:22a8774452ac

// Copyright (c) 2013 by István Váradi

// This file is part of VSCPL, a simple cross-platform utility library

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:

// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// The views and conclusions contained in the software and documentation are those
// of the authors and should not be interpreted as representing official policies,
// either expressed or implied, of the FreeBSD Project.

//------------------------------------------------------------------------------

#include "WaitableEvent.h"

#include <poll.h>
#include <unistd.h>

#include <sys/eventfd.h>

//------------------------------------------------------------------------------

using hu::varadiistvan::scpl::io::WaitableEvent;

//------------------------------------------------------------------------------

WaitableEvent::WaitableEvent(Waiter* waiter) :
    Waitable(waiter, eventfd(0, (waiter==0) ? 0 : EFD_NONBLOCK), POLLIN),
    fired(false)
{
    if (fd<0) {
        setErrorCodeFromErrno();
    }
}

//------------------------------------------------------------------------------

WaitableEvent::~WaitableEvent()
{
    close(fd);
}

//------------------------------------------------------------------------------

void WaitableEvent::fire()
{
    static const uint64_t one = 1;
    if (write(fd, &one, sizeof(one))<0) {
        if (errno!=EAGAIN) {
            setErrorCodeFromErrno();
        }
    }
}

//------------------------------------------------------------------------------

bool WaitableEvent::check()
{
    if (doCheck()) {
        fired = false;
        return true;
    } else {
        return false;
    }
}

//------------------------------------------------------------------------------

bool WaitableEvent::isReady()
{
    return fired;
}

//------------------------------------------------------------------------------

void WaitableEvent::handleEvents(short events)
{
    if ((events&POLLIN)==POLLIN) {
        doCheck();
    }
}

//------------------------------------------------------------------------------

bool WaitableEvent::doCheck(bool fromHandleEvents)
{
    if (failed()) return false;
    if (!fromHandleEvents && fired) return true;

    uint64_t value = 0;
    if (read(fd, &value, sizeof(value))<0) {
        if (errno!=EAGAIN) {
            setErrorCodeFromErrno();
        }
    } else {
        fired = fired || value>0;
    }

    return fired;
}

//------------------------------------------------------------------------------
//------------------------------------------------------------------------------

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// mode: C++
// c-basic-offset: 4
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