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// $Id: ReventLoop.cpp 686 2015-06-04 21:08:08Z mueller $

//

// Copyright 2013-2015 by Walter F.J. Mueller <W.F.J.Mueller@gsi.de>

//

// This program is free software; you may redistribute and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation, either version 2, or at your option any later version.

//

// This program is distributed in the hope that it will be useful, but

// WITHOUT ANY WARRANTY, without even the implied warranty of MERCHANTABILITY

// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for complete details.

// 

// Revision History: 

// Date         Rev Version  Comment

// 2015-04-04   662   1.2    BUGFIX: fix race in Stop(), add UnStop,StopPending

// 2013-04-27   511   1.1.3  BUGFIX: logic in DoCall() fixed (loop range)

// 2013-03-05   495   1.1.2  add exception catcher to EventLoop

// 2013-03-01   493   1.1.1  DoCall(): remove handler on negative return

// 2013-02-22   491   1.1    use new RlogFile/RlogMsg interfaces

// 2013-01-11   473   1.0    Initial version

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

/*!

  \file

  \version $Id: ReventLoop.cpp 686 2015-06-04 21:08:08Z mueller $

  \brief   Implemenation of class ReventLoop.

*/

#include <string.h>

#include <poll.h>

#include <errno.h>

#include "boost/bind.hpp" 

#include "boost/thread/locks.hpp"

#include "librtools/Rexception.hpp"

#include "librtools/RosPrintf.hpp"

#include "librtools/RosFill.hpp"

#include "librtools/RlogMsg.hpp"

#include "ReventLoop.hpp"

using namespace std;

/*!

  \class Retro::ReventLoop

  \brief FIXME_docs

*/

// all method definitions in namespace Retro

namespace Retro {

//------------------------------------------+-----------------------------------

//! FIXME_docs

ReventLoop::ReventLoop()

  : fStopPending(false),

    fUpdatePoll(false),

    fPollDscMutex(),

    fPollDsc(),

    fPollFd(),

    fPollHdl(),

    fTraceLevel(0),

    fspLog()

{}

//------------------------------------------+-----------------------------------

//! FIXME_docs

ReventLoop::~ReventLoop()

{}

//------------------------------------------+-----------------------------------

//! FIXME_docs

// by default handlers should start with: 

//     if (pfd.revents & (~pfd.events)) return -1;

void ReventLoop::AddPollHandler(const pollhdl_t& pollhdl,

                                int fd, short events)

{

  boost::lock_guard<boost::mutex> lock(fPollDscMutex);

  for (size_t i=0; i<fPollDsc.size(); i++) {

    if (fPollDsc[i].fFd     == fd &&

        fPollDsc[i].fEvents == events) {

      throw Rexception("ReventLoop::AddPollHandler()",

                       "Bad args: duplicate handler");

    }

  }

  fPollDsc.push_back(PollDsc(pollhdl,fd,events));

  fUpdatePoll = true;

  if (fspLog && fTraceLevel >= 1) {

    RlogMsg lmsg(*fspLog, 'I');

    lmsg << "eloop: add handler: " << fd << "," << RosPrintf(events,"x");

  }

  return;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

void ReventLoop::RemovePollHandler(int fd, short events, bool nothrow)

{

  boost::lock_guard<boost::mutex> lock(fPollDscMutex);

  for (size_t i=0; i<fPollDsc.size(); i++) {

    if (fPollDsc[i].fFd     == fd &&

        fPollDsc[i].fEvents == events) {

      fPollDsc.erase(fPollDsc.begin()+i);

      fUpdatePoll = true;

      if (fspLog && fTraceLevel >= 1) {

        RlogMsg lmsg(*fspLog, 'I');

        lmsg << "eloop: remove handler: " << fd << "," << RosPrintf(events,"x");

      }

      return;

    }

  }

  if (!nothrow) throw Rexception("ReventLoop::RemovePollHandler()",

                                 "Bad args: unknown handler");

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

bool ReventLoop::TestPollHandler(int fd, short events)

{

  boost::lock_guard<boost::mutex> lock(fPollDscMutex);

  for (size_t i=0; i<fPollDsc.size(); i++) {

    if (fPollDsc[i].fFd     == fd &&

        fPollDsc[i].fEvents == events) {

      return true;

    }

  }

  return false;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

void ReventLoop::RemovePollHandler(int fd)

{

  boost::lock_guard<boost::mutex> lock(fPollDscMutex);

  for (size_t i=0; i<fPollDsc.size(); i++) {

    if (fPollDsc[i].fFd == fd) {

      fPollDsc.erase(fPollDsc.begin()+i);

      fUpdatePoll = true;

      i--;                                  // re-probe this index

    }

  }

  return;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

void ReventLoop::EventLoop()

{

  fUpdatePoll = true;

  try {

    while (!StopPending()) {

      int irc = DoPoll();

      if (fPollFd.size() == 0) break;

      if (irc>0) DoCall();

    }

  } catch (exception& e) {

    if (fspLog) {

      RlogMsg lmsg(*fspLog, 'F');

      lmsg << "eloop: crashed with exception: " << e.what();

    }

    return;

  }

  return;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

void ReventLoop::Dump(std::ostream& os, int ind, const char* text) const

{

  RosFill bl(ind);

  os << bl << (text?text:"--") << "ReventLoop @ " << this << endl;

  os << bl << "  fStopPending:    " << fStopPending << endl;

  os << bl << "  fUpdatePoll:     " << fUpdatePoll << endl;

  {

    boost::lock_guard<boost::mutex> lock(((ReventLoop*)this)->fPollDscMutex);

    os << bl << "  fPollDsc.size    " << fPollDsc.size() << endl;

    os << bl << "  fPollFd.size     " << fPollFd.size()  << endl;

    os << bl << "  fPollHdl.size    " << fPollHdl.size() << endl;

    for (size_t i=0; i<fPollDsc.size(); i++) {

      os << bl << "    [" << RosPrintf(i,"d",3) << "]:"

         << " fd:" << RosPrintf(fPollDsc[i].fFd,"d",3)

         << " evt:" << RosPrintf(fPollDsc[i].fEvents,"x",2)

         << " hdl:" << (bool)fPollDsc[i].fHandler

         << endl;

    }

  }

  os << bl << "  fTraveLevel:     " << fTraceLevel << endl;

  os << bl << "  fspLog:          " << fspLog.get() << endl;

  return;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

int ReventLoop::DoPoll(int timeout)

{

  if (fUpdatePoll) {

    boost::lock_guard<boost::mutex> lock(fPollDscMutex);

    fPollFd.resize(fPollDsc.size());

    fPollHdl.resize(fPollDsc.size());

    for (size_t i=0; i<fPollDsc.size(); i++) {

      fPollFd[i].fd      = fPollDsc[i].fFd;

      fPollFd[i].events  = fPollDsc[i].fEvents;

      fPollFd[i].revents = 0;

      fPollHdl[i] = fPollDsc[i].fHandler;

    }

    fUpdatePoll = false;

    if (fspLog && fTraceLevel >= 1) {

      RlogMsg lmsg(*fspLog, 'I');

      lmsg << "eloop: redo pollfd list, size=" << fPollDsc.size() << endl;

    }

  }

  if (fPollFd.size() == 0) return 0;

  int irc = poll(fPollFd.data(), fPollFd.size(), timeout);

  if (irc < 0 && errno == EINTR) return 0;

  if (irc < 0)

    throw Rexception("ReventLoop::EventLoop()", "poll() failed: ", errno);

  if (fspLog && fTraceLevel >= 2) {

    RlogMsg lmsg(*fspLog, 'I');

    lmsg << "eloop: poll(): rc=" << irc;

    for (size_t i=0; i<fPollFd.size(); i++) {

      if (fPollFd[i].revents == 0) continue;

      lmsg << " (" << fPollFd[i].fd

           << "," << RosPrintf(fPollFd[i].events,"x")

           << "," << RosPrintf(fPollFd[i].revents,"x") << ")";

    }

  }

  return irc;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

void ReventLoop::DoCall(void)

{

  for (size_t i=0; i<fPollFd.size(); i++) {

    if (fPollFd[i].revents) {

      int irc = fPollHdl[i](fPollFd[i]);

      // remove handler negative return (nothrow=true to prevent remove race)

      if (irc < 0) {

        if (fspLog && fTraceLevel >= 1) {

          RlogMsg lmsg(*fspLog, 'I');

          lmsg << "eloop: handler(" << fPollFd[i].fd

               << "," << RosPrintf(fPollFd[i].events,"x")

               << ") got " << RosPrintf(fPollFd[i].revents,"x")

               << " and requested removal";

        }

        RemovePollHandler(fPollFd[i].fd, fPollFd[i].events, true);

      }

    }

  }

  return;

}

} // end namespace Retro