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session_feedback.cc

/*
    Copyright (C) 2004 Paul Davis 

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, 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 more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    $Id: session_feedback.cc,v 1.9 2005/12/28 21:38:53 essej Exp $
*/

#include <string>
#include <cmath>
#include <cerrno>
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>

#include <midi++/types.h>
#include <midi++/port.h>
#include <midi++/manager.h>
#include <pbd/error.h>
#include <pbd/lockmonitor.h>
#include <pbd/pthread_utils.h>

#include <ardour/configuration.h>
#include <ardour/audioengine.h>
#include <ardour/session.h>
#include <ardour/audio_track.h>
#include <ardour/diskstream.h>

#include "i18n.h"

using namespace std;
using namespace ARDOUR;
using namespace SigC;

int
Session::init_feedback ()
{
      if (pipe (feedback_request_pipe) != 0) {
            error << compose (_("cannot create feedback request pipe (%1)"),
                          strerror (errno))
                  << endmsg;
            return -1;
      }

      if (fcntl (feedback_request_pipe[0], F_SETFL, O_NONBLOCK)) {
            error << compose(_("UI: cannot set O_NONBLOCK on "    "signal read pipe (%1)"), strerror (errno)) << endmsg;
            return -1;
      }

      if (fcntl (feedback_request_pipe[1], F_SETFL, O_NONBLOCK)) {
            error << compose(_("UI: cannot set O_NONBLOCK on "    "signal write pipe (%1)"), strerror (errno)) << endmsg;
            return -1;
      }

      active_feedback = 0;
      midi_feedback = false;

      /* add possible feedback functions here */
      
      feedback_functions.push_back (slot (*this, &Session::feedback_generic_midi_function));

      if (pthread_create_and_store ("feedback", &feedback_thread, 0, _feedback_thread_work, this)) {
            error << _("Session: could not create feedback thread") << endmsg;
            return -1;
      }

      return 0;
}     

int
Session::poke_feedback (FeedbackRequest::Type why)
{
      char c = (char) why;
      return !(write (feedback_request_pipe[1], &c, 1) == 1);
}

int
Session::start_feedback ()
{
      return poke_feedback (FeedbackRequest::Start);
}

int
Session::stop_feedback ()
{
      return poke_feedback (FeedbackRequest::Stop);
}

void
Session::terminate_feedback ()
{
      void* status;
      poke_feedback (FeedbackRequest::Quit);
      pthread_join (feedback_thread, &status);
}

void*
Session::_feedback_thread_work (void* arg)
{
      return static_cast<Session*> (arg)->feedback_thread_work ();
}

void*
Session::feedback_thread_work ()
{
      PBD::ThreadCreated (pthread_self(), X_("Feedback"));
      struct pollfd pfd[1];
      int timeout;

      pthread_setcancelstate (PTHREAD_CANCEL_ENABLE, 0);
      pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);

      if (active_feedback) {
            /* XXX use Config->feedback_interval_usecs()*/;
            timeout = max (5, (int) Config->get_midi_feedback_interval_ms());
      } else {
            timeout = -1;
      }

      while (1) {

            pfd[0].fd = feedback_request_pipe[0];
            pfd[0].events = POLLIN|POLLHUP|POLLERR;

            if (poll (pfd, 1, timeout) < 0) {
                  if (errno == EINTR) {
                        continue;
                  }
                  error << compose (_("Feedback thread poll failed (%1)"),
                                strerror (errno))
                        << endmsg;
                  break;
            }

            if (pfd[0].revents & ~POLLIN) {
                  error << _("Error on feedback thread request pipe") << endmsg;
                  break;
            }

            if (pfd[0].revents & POLLIN) {

                  char req;
                  
                  /* empty the pipe of all current requests */

                  while (1) {
                        size_t nread = read (feedback_request_pipe[0], &req, sizeof (req));

                        if (nread == 1) {
                              switch ((FeedbackRequest::Type) req) {
                              
                              case FeedbackRequest::Start:
                                    timeout = max (5, (int) Config->get_midi_feedback_interval_ms());
                                    active_feedback++;
                                    break;
                                    
                              case FeedbackRequest::Stop:
                                    timeout = -1;
                                    if (active_feedback) {
                                          active_feedback--;
                                    } 
                                    break;
                                    
                              case FeedbackRequest::Quit:
                                    pthread_exit_pbd (0);
                                    /*NOTREACHED*/
                                    break;
                                    
                              default:
                                    break;
                              }

                        } else if (nread == 0) {
                              break;
                        } else if (errno == EAGAIN) {
                              break;
                        } else {
                              fatal << _("Error reading from feedback request pipe") << endmsg;
                              /*NOTREACHED*/
                        }
                  }
            }
            
            if (!active_feedback || transport_stopped()) {
                  continue;
            }

            for (list<FeedbackFunctionPtr>::iterator i = feedback_functions.begin(); i != feedback_functions.end(); ) {
                  
                  list<FeedbackFunctionPtr>::iterator tmp;
                  
                  tmp = i;
                  ++tmp;
                  
                  if ((*i).call ()) {
                        feedback_functions.erase (i);
                  }
                  
                  i = tmp;
            }
      }
      
      return 0;
}

int
Session::feedback_generic_midi_function ()
{
      const int32_t bufsize = 16 * 1024;
      int32_t bsize = bufsize;
      MIDI::byte* buf = new MIDI::byte[bufsize];
      MIDI::byte* end = buf;

      {
            RWLockMonitor lm (route_lock, false, __LINE__, __FILE__);
            
            for (RouteList::iterator i = routes.begin(); i != routes.end(); ++i) {
                  end = (*i)->write_midi_feedback (end, bsize);
            }
      }

      if (end == buf) {
            delete [] buf;
            return 0;
      } 
      
      deliver_midi (_midi_port, buf, (int32_t) (end - buf));

      //cerr << "MIDI feedback: wrote " << (int32_t) (end - buf) << " to midi port\n";
            

      return 0;
}
      

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