source: vscpl/src/hu/varadiistvan/scpl/io/_posix/Waiter.cc

// 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 "Waiter.h"

#include "Waitable.h"

#include <cassert>
#include <cerrno>

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

using hu::varadiistvan::scpl::io::Waiter;

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

inline bool Waiter::hasReady() const
{
    for(waitables_t::const_iterator i = waitables.begin(); i!=waitables.end();
        ++i)
    {
        Waitable* waitable = i->second;
        if (waitable->ready()) {
            return true;
        }
    }
    return false;
}

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

inline size_t Waiter::setupPollFDs(pollfd* pollFDs)
{
    size_t numValid = 0;

    for(waitables_t::const_iterator i = waitables.begin(); i!=waitables.end();
        ++i)
    {
        Waitable* waitable = i->second;
        if (waitable->events==0) continue;

        pollfd& pollFD = pollFDs[numValid++];

        pollFD.fd = waitable->fd;
        pollFD.events = waitable->events;
        pollFD.revents = 0;
    }

    return numValid;
}

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

inline void Waiter::processPollFDs(const pollfd* pollFDs, size_t size)
{
    for(size_t i = 0; i<size; ++i) {
        const pollfd& pollFD = pollFDs[i];
        if (pollFD.revents!=0) {
            waitables_t::iterator j = waitables.find(pollFD.fd);
            assert(j!=waitables.end());
            Waitable* waitable = j->second;
            waitable->handleEvents(pollFD.revents);
        }
    }
}

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

Waiter::~Waiter()
{
    for(waitables_t::iterator i = waitables.begin(); i!=waitables.end(); ++i)
    {
        Waitable* waitable = i->second;
        waitable->waiter = 0;
    }
}

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

bool Waiter::wait(int timeout)
{
    if (hasReady()) return true;

    pollfd pollFDs[numWaitables];
    size_t numValid = setupPollFDs(pollFDs);

    int result = poll(pollFDs, numValid, timeout);

    if (result<0) {
        setErrorCode(errno);
        return false;
    } else if (result>0) {
        processPollFDs(pollFDs, numValid);
    }

    return hasReady();
}

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

void Waiter::add(Waitable* waitable)
{
    assert(waitable->fd>=0);
    assert(waitables.find(waitable->fd)==waitables.end());
    waitables[waitable->fd] = waitable;
    ++numWaitables;
}

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

void Waiter::remove(Waitable* waitable)
{
    assert(numWaitables>0);
    assert(waitables.find(waitable->fd)!=waitables.end());
    assert(waitables[waitable->fd]==waitable);
    waitables.erase(waitable->fd);
    --numWaitables;
}

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

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