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/*
MIDI Sequencer C++ library
Copyright (C) 2006-2024, Pedro Lopez-Cabanillas <plcl@users.sf.net>
This library 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 3 of the License, or
(at your option) any later version.
This library 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, see <http://www.gnu.org/licenses/>.
*/
extern "C" {
#include <alsa/asoundlib.h>
}
#include <QReadLocker>
#include <QWriteLocker>
#include <drumstick/alsaclient.h>
#include <drumstick/alsaqueue.h>
#include <drumstick/playthread.h>
/**
* @file playthread.cpp
* Implementation of a sequencer output thread
*/
/**
* @addtogroup PlayThread
* @{
* ALSA Sequencer easy playback functionality.
* SequencerOutputThread provides MIDI sequence playback.
*
* This is an abstract class that must be extended providing
* an implementation for the pure virtual methods:
* SequencerOutputThread::hasNext() and SequencerOutputThread::nextEvent()
* before using it for MIDI sequence playback. You can use any structure or
* class you prefer to store the SequencerEvent objects, but they must be
* provided ordered by time. A simplistic Song definition may be:
*
* @code
* typedef QList<SequencerEvent> Song;
* @endcode
*
* Using this class is optional. You may prefer another mechanism to
* manage playback actions. This class uses a thread to manage the
* sequence playback as a background task.
* @}
*/
namespace drumstick {
namespace ALSA {
const int TIMEOUT = 100;
/**
* Constructor
* @param seq Existing MidiClient object pointer
* @param portId Numeric input/output port identifier
*/
SequencerOutputThread::SequencerOutputThread(MidiClient *seq, int portId)
: QThread(),
m_MidiClient(seq),
m_Queue(nullptr),
m_PortId(portId),
m_Stopped(false),
m_QueueId(0),
m_npfds(0),
m_pfds(nullptr)
{
if (m_MidiClient != nullptr) {
m_Queue = m_MidiClient->getQueue();
m_QueueId = m_Queue->getId();
}
}
/**
* Checks if stop has been requested
* @return True if stop has been requested
* @since 0.2.0
*/
bool
SequencerOutputThread::stopRequested()
{
QReadLocker locker(&m_mutex);
return m_Stopped;
}
/**
* Stops the playback task
*/
void
SequencerOutputThread::stop()
{
QWriteLocker locker(&m_mutex);
m_Stopped = true;
locker.unlock();
while (isRunning()) {
wait(TIMEOUT);
}
}
/**
* Sends an echo event, with the same PortId as sender and destination.
* @param tick Event schedule time in ticks.
*/
void
SequencerOutputThread::sendEchoEvent(int tick)
{
if (!stopRequested() && m_MidiClient != nullptr) {
SystemEvent ev(SND_SEQ_EVENT_ECHO);
ev.setSource(m_PortId);
ev.setDestination(m_MidiClient->getClientId(), m_PortId);
ev.scheduleTick(m_QueueId, tick, false);
sendSongEvent(&ev);
}
}
/**
* Sends a SequencerEvent
* @param ev SequencerEvent object pointer
*/
void
SequencerOutputThread::sendSongEvent(SequencerEvent* ev)
{
if (m_MidiClient != nullptr) {
while (!stopRequested() &&
(snd_seq_event_output_direct(m_MidiClient->getHandle(), ev->getHandle()) < 0)) {
poll(m_pfds, m_npfds, TIMEOUT);
}
}
}
/**
* Flush the ALSA output buffer.
*/
void
SequencerOutputThread::drainOutput()
{
if (!stopRequested() && m_MidiClient != nullptr) {
while (!stopRequested() && (snd_seq_drain_output(m_MidiClient->getHandle()) < 0)) {
poll(m_pfds, m_npfds, TIMEOUT);
}
}
}
/**
* Waits until the ALSA output queue is empty (all the events have been played.)
*/
void
SequencerOutputThread::syncOutput()
{
if (!stopRequested() && m_MidiClient != nullptr) {
m_MidiClient->synchronizeOutput();
}
}
/**
* Thread process loop
*/
void SequencerOutputThread::run()
{
if (m_MidiClient != nullptr) {
try {
unsigned int last_tick;
m_npfds = snd_seq_poll_descriptors_count(m_MidiClient->getHandle(), POLLOUT);
m_pfds = (pollfd*) calloc(m_npfds, sizeof(pollfd));
snd_seq_poll_descriptors(m_MidiClient->getHandle(), m_pfds, m_npfds, POLLOUT);
last_tick = getInitialPosition();
if (last_tick == 0) {
m_Queue->start();
} else {
m_Queue->setTickPosition(last_tick);
m_Queue->continueRunning();
}
while (!stopRequested() && hasNext()) {
SequencerEvent* ev = nextEvent();
if (!stopRequested() && !SequencerEvent::isConnectionChange(ev)) {
sendSongEvent(ev);
}
if (getEchoResolution() > 0) {
while (!stopRequested() && (last_tick < ev->getTick())) {
last_tick += getEchoResolution();
sendEchoEvent(last_tick);
}
}
}
if (stopRequested()) {
m_Queue->clear();
Q_EMIT playbackStopped();
} else {
drainOutput();
syncOutput();
if (stopRequested())
Q_EMIT playbackStopped();
else
Q_EMIT playbackFinished();
}
m_Queue->stop();
} catch (...) {
qWarning("exception in output thread");
}
m_npfds = 0;
free(m_pfds);
m_pfds = nullptr;
}
}
/**
* Starts the playback thread
* @param priority Thread priority, default is InheritPriority
*/
void SequencerOutputThread::start( Priority priority )
{
QWriteLocker locker(&m_mutex);
m_Stopped = false;
QThread::start( priority );
}
} // namespace ALSA
} // namespace drumstick
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