async_midi_port.cc

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/*
    Copyright (C) 1998 Paul Barton-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.

    $Id$
*/

#include <iostream>
#include <vector>

#include <glibmm/timer.h>

#include "pbd/error.h"
#include "pbd/stacktrace.h"

#include "midi++/types.h"

#include "ardour/async_midi_port.h"
#include "ardour/audioengine.h"
#include "ardour/midi_buffer.h"

using namespace MIDI;
using namespace ARDOUR;
using namespace std;
using namespace PBD;

pthread_t AsyncMIDIPort::_process_thread;

#define port_engine AudioEngine::instance()->port_engine()

AsyncMIDIPort::AsyncMIDIPort (string const & name, PortFlags flags)
        : MidiPort (name, flags)
        , MIDI::Port (name, MIDI::Port::Flags (0))
        , _currently_in_cycle (false)
        , _last_write_timestamp (0)
        , have_timer (false)
        , output_fifo (512)
        , input_fifo (1024)
        , _xthread (true)
{
}

AsyncMIDIPort::~AsyncMIDIPort ()
{
}

void
AsyncMIDIPort::set_timer (boost::function<MIDI::framecnt_t (void)>& f)
{
        timer = f;
        have_timer = true;
}

void
AsyncMIDIPort::flush_output_fifo (MIDI::pframes_t nframes)
{
        RingBuffer< Evoral::Event<double> >::rw_vector vec = { { 0, 0 }, { 0, 0 } };
        size_t written;

        output_fifo.get_read_vector (&vec);

        MidiBuffer& mb (get_midi_buffer (nframes));
                        
        if (vec.len[0]) {
                Evoral::Event<double>* evp = vec.buf[0];
                
                for (size_t n = 0; n < vec.len[0]; ++n, ++evp) {
                        mb.push_back (evp->time(), evp->size(), evp->buffer());
                }
        }
        
        if (vec.len[1]) {
                Evoral::Event<double>* evp = vec.buf[1];

                for (size_t n = 0; n < vec.len[1]; ++n, ++evp) {
                        mb.push_back (evp->time(), evp->size(), evp->buffer());
                }
        }
        
        if ((written = vec.len[0] + vec.len[1]) != 0) {
                output_fifo.increment_read_idx (written);
        }
}

void
AsyncMIDIPort::cycle_start (MIDI::pframes_t nframes)
{
        _currently_in_cycle = true;
        MidiPort::cycle_start (nframes);

        /* dump anything waiting in the output FIFO at the start of the port
         * buffer
         */

        if (ARDOUR::Port::sends_output()) {
                flush_output_fifo (nframes);
        } 
        
        /* copy incoming data from the port buffer into the input FIFO
           and if necessary wakeup the reader
        */

        if (ARDOUR::Port::receives_input()) {
                MidiBuffer& mb (get_midi_buffer (nframes));
                framecnt_t when;
                
                if (have_timer) {
                        when = timer ();
                } else {
                        when = AudioEngine::instance()->sample_time_at_cycle_start();
                }

                for (MidiBuffer::iterator b = mb.begin(); b != mb.end(); ++b) {
                        if (!have_timer) {
                                when += (*b).time();
                        }
                        input_fifo.write (when, (Evoral::EventType) 0, (*b).size(), (*b).buffer());
                }

                if (!mb.empty()) {
                        _xthread.wakeup ();
                }
        }
}

void
AsyncMIDIPort::cycle_end (MIDI::pframes_t nframes)
{
        if (ARDOUR::Port::sends_output()) {
                /* move any additional data from output FIFO into the port
                   buffer.
                */
                flush_output_fifo (nframes);
        }

        MidiPort::cycle_end (nframes);

        _currently_in_cycle = false;
}

void
AsyncMIDIPort::drain (int check_interval_usecs)
{
        RingBuffer< Evoral::Event<double> >::rw_vector vec = { { 0, 0 }, { 0, 0} };

        if (!AudioEngine::instance()->running() || AudioEngine::instance()->session() == 0) {
                /* no more process calls - it will never drain */
                return;
        }


        if (is_process_thread()) {
                error << "Process thread called MIDI::AsyncMIDIPort::drain() - this cannot work" << endmsg;
                return;
        }

        while (1) {
                output_fifo.get_write_vector (&vec);
                if (vec.len[0] + vec.len[1] >= output_fifo.bufsize() - 1) {
                        break;
                }
                Glib::usleep (check_interval_usecs);
        }
}

int
AsyncMIDIPort::write (const MIDI::byte * msg, size_t msglen, MIDI::timestamp_t timestamp)
{
        int ret = 0;

        if (!ARDOUR::Port::sends_output()) {
                return ret;
        }

        if (!is_process_thread()) {

                /* this is the best estimate of "when" this MIDI data is being
                 * delivered
                 */
                
                _parser->set_timestamp (AudioEngine::instance()->sample_time() + timestamp);
                for (size_t n = 0; n < msglen; ++n) {
                        _parser->scanner (msg[n]);
                }

                Glib::Threads::Mutex::Lock lm (output_fifo_lock);
                RingBuffer< Evoral::Event<double> >::rw_vector vec = { { 0, 0 }, { 0, 0} };
                
                output_fifo.get_write_vector (&vec);

                if (vec.len[0] + vec.len[1] < 1) {
                        error << "no space in FIFO for non-process thread MIDI write" << endmsg;
                        return 0;
                }

                if (vec.len[0]) {
                        if (!vec.buf[0]->owns_buffer()) {
                                vec.buf[0]->set_buffer (0, 0, true);
                        }
                        vec.buf[0]->set (msg, msglen, timestamp);
                } else {
                        if (!vec.buf[1]->owns_buffer()) {
                                vec.buf[1]->set_buffer (0, 0, true);
                        }
                        vec.buf[1]->set (msg, msglen, timestamp);
                }

                output_fifo.increment_write_idx (1);
                
                ret = msglen;

        } else {

                _parser->set_timestamp (AudioEngine::instance()->sample_time_at_cycle_start() + timestamp);
                for (size_t n = 0; n < msglen; ++n) {
                        _parser->scanner (msg[n]);
                }

                if (timestamp >= _cycle_nframes) {
                        std::cerr << "attempting to write MIDI event of " << msglen << " MIDI::bytes at time "
                                  << timestamp << " of " << _cycle_nframes
                                  << " (this will not work - needs a code fix)"
                                  << std::endl;
                }

                /* This is the process thread, which makes checking
                 * _currently_in_cycle atomic and safe, since it is only
                 * set from cycle_start() and cycle_end(), also called
                 * only from the process thread.
                 */

                if (_currently_in_cycle) {

                        MidiBuffer& mb (get_midi_buffer (_cycle_nframes));
                        
                        if (timestamp == 0) {
                                timestamp = _last_write_timestamp;
                        } 
                        
                        if (mb.push_back (timestamp, msglen, msg)) {
                                ret = msglen;
                                _last_write_timestamp = timestamp;

                        } else {
                                cerr << "AsyncMIDIPort (" << ARDOUR::Port::name() << "): write of " << msglen << " @ " << timestamp << " failed\n" << endl;
                                PBD::stacktrace (cerr, 20);
                                ret = 0;
                        }
                } else {
                        cerr << "write to JACK midi port failed: not currently in a process cycle." << endl;
                        PBD::stacktrace (cerr, 20);
                }
        }

        return ret;
}


int
AsyncMIDIPort::read (MIDI::byte *, size_t)
{
        if (!ARDOUR::Port::receives_input()) {
                return 0;
        }
        
        timestamp_t time;
        Evoral::EventType type;
        uint32_t size;
        vector<MIDI::byte> buffer(input_fifo.capacity());

        while (input_fifo.read (&time, &type, &size, &buffer[0])) {
                _parser->set_timestamp (time);
                for (uint32_t i = 0; i < size; ++i) {
                        _parser->scanner (buffer[i]);
                }
        }

        return 0;
}

void
AsyncMIDIPort::parse (MIDI::framecnt_t)
{
        MIDI::byte buf[1];

        /* see ::read() to realize why buf is not used */
        read (buf, sizeof (buf));
}

void
AsyncMIDIPort::set_process_thread (pthread_t thr)
{
        _process_thread = thr;
}

bool
AsyncMIDIPort::is_process_thread()
{
        return pthread_equal (pthread_self(), _process_thread);
}