MidiSessionALSA.cc

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#include "MidiSessionALSA.hh"
#include "CliComm.hh"
#include "MidiOutDevice.hh"
#include "MidiInDevice.hh"
#include "MidiInConnector.hh"
#include "EventListener.hh"
#include "EventDistributor.hh"
#include "PlugException.hh"
#include "PluggingController.hh"
#include "Scheduler.hh"
#include "narrow.hh"
#include "serialize.hh"
#include "circular_buffer.hh"
#include "checked_cast.hh"
#include <iostream>
#include <memory>
#include <thread>
 
 
namespace openmsx {
 
// MidiOutALSA ==============================================================
 
class MidiOutALSA final : public MidiOutDevice {
public:
        MidiOutALSA(snd_seq_t& seq,
                    snd_seq_client_info_t& cinfo, snd_seq_port_info_t& pinfo);
        MidiOutALSA(const MidiOutALSA&) = delete;
        MidiOutALSA(MidiOutALSA&&) = delete;
        MidiOutALSA& operator=(const MidiOutALSA&) = delete;
        MidiOutALSA& operator=(MidiOutALSA&&) = delete;
        ~MidiOutALSA() override;
 
        // Pluggable
        void plugHelper(Connector& connector, EmuTime::param time) override;
        void unplugHelper(EmuTime::param time) override;
        [[nodiscard]] std::string_view getName() const override;
        [[nodiscard]] std::string_view getDescription() const override;
 
        // MidiOutDevice
        void recvMessage(
                        const std::vector<uint8_t>& message, EmuTime::param time) override;
 
        template<typename Archive>
        void serialize(Archive& ar, unsigned version);
 
private:
        void connect();
        void disconnect();
 
private:
        snd_seq_t& seq;
        snd_midi_event_t* event_parser;
        int sourcePort = -1;
        int destClient;
        int destPort;
        std::string name;
        std::string desc;
        bool connected = false;
};
 
MidiOutALSA::MidiOutALSA(
                snd_seq_t& seq_,
                snd_seq_client_info_t& cinfo, snd_seq_port_info_t& pinfo)
        : seq(seq_)
        , destClient(snd_seq_port_info_get_client(&pinfo))
        , destPort(snd_seq_port_info_get_port(&pinfo))
        , name(snd_seq_client_info_get_name(&cinfo))
        , desc(snd_seq_port_info_get_name(&pinfo))
{
}
 
MidiOutALSA::~MidiOutALSA()
{
        if (connected) {
                disconnect();
        }
}
 
void MidiOutALSA::plugHelper(Connector& /*connector_*/, EmuTime::param /*time*/)
{
        connect();
}
 
void MidiOutALSA::unplugHelper(EmuTime::param /*time*/)
{
        disconnect();
}
 
void MidiOutALSA::connect()
{
        sourcePort = snd_seq_create_simple_port(
                &seq, "MIDI out pluggable",
                0, SND_SEQ_PORT_TYPE_MIDI_GENERIC);
        if (sourcePort < 0) {
                throw PlugException(
                        "Failed to create ALSA port: ", snd_strerror(sourcePort));
        }
 
        if (int err = snd_seq_connect_to(&seq, sourcePort, destClient, destPort)) {
                snd_seq_delete_simple_port(&seq, sourcePort);
                throw PlugException(
                        "Failed to connect to ALSA port "
                        "(", destClient, ':', destPort, ")"
                        ": ", snd_strerror(err));
        }
 
        snd_midi_event_new(MAX_MESSAGE_SIZE, &event_parser);
 
        connected = true;
}
 
void MidiOutALSA::disconnect()
{
        snd_midi_event_free(event_parser);
        snd_seq_disconnect_to(&seq, sourcePort, destClient, destPort);
        snd_seq_delete_simple_port(&seq, sourcePort);
 
        connected = false;
}
 
std::string_view MidiOutALSA::getName() const
{
        return name;
}
 
std::string_view MidiOutALSA::getDescription() const
{
        return desc;
}
 
void MidiOutALSA::recvMessage(
                const std::vector<uint8_t>& message, EmuTime::param /*time*/)
{
        snd_seq_event_t ev;
        snd_seq_ev_clear(&ev);
 
        // Set routing.
        snd_seq_ev_set_source(&ev, narrow_cast<uint8_t>(sourcePort));
        snd_seq_ev_set_subs(&ev);
 
        // Set message.
        if (auto encodeLen = snd_midi_event_encode(
                        event_parser, message.data(), narrow<long>(message.size()), &ev);
            encodeLen < 0) {
                std::cerr << "Error encoding MIDI message of type "
                          << std::hex << int(message[0]) << std::dec
                          << ": " << snd_strerror(narrow<int>(encodeLen)) << '\n';
                return;
        }
        if (ev.type == SND_SEQ_EVENT_NONE) {
                std::cerr << "Incomplete MIDI message of type "
                          << std::hex << int(message[0]) << std::dec << '\n';
                return;
        }
 
        // Send event.
        snd_seq_ev_set_direct(&ev);
        if (int err = snd_seq_event_output(&seq, &ev); err < 0) {
                std::cerr << "Error sending MIDI event: "
                          << snd_strerror(err) << '\n';
        }
        snd_seq_drain_output(&seq);
}
 
template<typename Archive>
void MidiOutALSA::serialize(Archive& /*ar*/, unsigned /*version*/)
{
        if constexpr (Archive::IS_LOADER) {
                connect();
        }
}
INSTANTIATE_SERIALIZE_METHODS(MidiOutALSA);
REGISTER_POLYMORPHIC_INITIALIZER(Pluggable, MidiOutALSA, "MidiOutALSA");
 
// MidiInALSA ==============================================================
class MidiInALSA final : public MidiInDevice, private EventListener
{
public:
        MidiInALSA(
                        EventDistributor& eventDistributor, Scheduler& scheduler, snd_seq_t& seq,
                        snd_seq_client_info_t& cinfo, snd_seq_port_info_t& pinfo);
        ~MidiInALSA() override;
 
        // Pluggable
        void plugHelper(Connector& connector, EmuTime::param time) override;
        void unplugHelper(EmuTime::param time) override;
        [[nodiscard]] std::string_view getName() const override;
        [[nodiscard]] std::string_view getDescription() const override;
 
        // MidiInDevice
        void signal(EmuTime::param time) override;
 
        template<typename Archive>
        void serialize(Archive& ar, unsigned version);
 
private:
        void run();
        void connect();
        void disconnect();
 
        // EventListener
        bool signalEvent(const Event& event) override;
 
private:
        EventDistributor& eventDistributor;
        Scheduler& scheduler;
        std::thread thread;
        snd_seq_t& seq;
        snd_midi_event_t* event_parser;
        int destinationPort = -1;
        int srcClient;
        int srcPort;
        std::string name;
        std::string desc;
        bool connected = false;
        bool stop = false;
        cb_queue<uint8_t> queue;
        std::mutex mutex; // to protect queue
};
 
MidiInALSA::MidiInALSA(
                EventDistributor& eventDistributor_,
                Scheduler& scheduler_,
                snd_seq_t& seq_,
                snd_seq_client_info_t& cinfo, snd_seq_port_info_t& pinfo)
        : eventDistributor(eventDistributor_)
        , scheduler(scheduler_)
        , seq(seq_)
        , srcClient(snd_seq_port_info_get_client(&pinfo))
        , srcPort(snd_seq_port_info_get_port(&pinfo))
        , name(snd_seq_client_info_get_name(&cinfo))
        , desc(snd_seq_port_info_get_name(&pinfo))
{
        eventDistributor.registerEventListener(EventType::MIDI_IN_ALSA, *this);
        if (snd_seq_port_info_get_capability(&pinfo) & (SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE)) {
                name.append(" (input)");
        }
}
 
MidiInALSA::~MidiInALSA()
{
        if (connected) {
                disconnect();
        }
        eventDistributor.unregisterEventListener(EventType::MIDI_IN_ALSA, *this);
}
 
void MidiInALSA::plugHelper(Connector& connector_, EmuTime::param /*time*/)
{
        auto& midiConnector = checked_cast<MidiInConnector&>(connector_);
        midiConnector.setDataBits(SerialDataInterface::DataBits::D8); // 8 data bits
        midiConnector.setStopBits(SerialDataInterface::StopBits::S1); // 1 stop bit
        midiConnector.setParityBit(false, SerialDataInterface::Parity::EVEN); // no parity
 
        setConnector(&midiConnector); // base class will do this in a moment,
                                      // but thread already needs it
        connect();
}
 
void MidiInALSA::unplugHelper(EmuTime::param /*time*/)
{
        if (connected) {
                disconnect();
        }
}
 
void MidiInALSA::connect()
{
        destinationPort = snd_seq_create_simple_port(
                &seq, "MIDI in pluggable",
                SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE, SND_SEQ_PORT_TYPE_MIDI_GENERIC);
        if (destinationPort < 0) {
                throw PlugException(
                        "Failed to create ALSA port: ", snd_strerror(destinationPort));
        }
 
        if (int err = snd_seq_connect_from(&seq, destinationPort, srcClient, srcPort)) {
                snd_seq_delete_simple_port(&seq, destinationPort);
                throw PlugException(
                        "Failed to connect to ALSA port "
                        "(", srcClient, ':', srcPort, ")"
                        ": ", snd_strerror(err));
        }
 
        snd_midi_event_new(MidiOutDevice::MAX_MESSAGE_SIZE, &event_parser);
        snd_midi_event_no_status(event_parser, 1);
 
        connected = true;
        stop = false;
 
        thread = std::thread([this]() { run(); });
}
 
void MidiInALSA::disconnect()
{
        stop = true;
        thread.join();
 
        snd_midi_event_free(event_parser);
        snd_seq_disconnect_from(&seq, destinationPort, srcClient, srcPort);
        snd_seq_delete_simple_port(&seq, destinationPort);
 
        connected = false;
}
 
void MidiInALSA::run()
{
        assert(isPluggedIn());
 
        auto npfd = snd_seq_poll_descriptors_count(&seq, POLLIN);
        std::vector<struct pollfd> pfd(npfd);
        snd_seq_poll_descriptors(&seq, pfd.data(), npfd, POLLIN);
 
        while (!stop) {
                if (poll(pfd.data(), npfd, 1000) > 0) {
                        snd_seq_event_t *ev = nullptr;
                        if (auto err = snd_seq_event_input(&seq, &ev); err < 0) {
                                std::cerr << "Error receiving MIDI event: "
                                        << snd_strerror(err) << '\n';
                                continue;
                        }
                        if (!ev) continue;
 
                        if (ev->type == SND_SEQ_EVENT_SYSEX) {
                                std::scoped_lock lock(mutex);
                                for (auto i : xrange(ev->data.ext.len)) {
                                        queue.push_back(static_cast<uint8_t*>(ev->data.ext.ptr)[i]);
                                }
 
                        } else {
                                std::array<uint8_t, 12> bytes = {};
                                auto size = snd_midi_event_decode(event_parser, bytes.data(), bytes.size(), ev);
                                if (size < 0) {
                                        std::cerr << "Error decoding MIDI event: "
                                                  << snd_strerror(int(size)) << '\n';
                                        snd_seq_free_event(ev);
                                        continue;
                                }
 
                                std::scoped_lock lock(mutex);
                                for (auto i : xrange(size)) {
                                        queue.push_back(bytes[i]);
                                }
                        }
                        snd_seq_free_event(ev);
                        eventDistributor.distributeEvent(MidiInALSAEvent());
                }
        }
}
 
void MidiInALSA::signal(EmuTime::param time)
{
        auto* conn = checked_cast<MidiInConnector*>(getConnector());
        if (!conn->acceptsData()) {
                std::scoped_lock lock(mutex);
                queue.clear();
                return;
        }
        if (!conn->ready()) return;
 
        uint8_t data;
        {
                std::scoped_lock lock(mutex);
                if (queue.empty()) return;
                data = queue.pop_front();
        }
        conn->recvByte(data, time);
}
 
// EventListener
bool MidiInALSA::signalEvent(const Event& /*event*/)
{
        if (isPluggedIn()) {
                signal(scheduler.getCurrentTime());
        } else {
                std::scoped_lock lock(mutex);
                queue.clear();
        }
        return false;
}
 
std::string_view MidiInALSA::getName() const
{
        return name;
}
 
std::string_view MidiInALSA::getDescription() const
{
        return desc;
}
 
template<typename Archive>
void MidiInALSA::serialize(Archive& /*ar*/, unsigned /*version*/)
{
        if constexpr (Archive::IS_LOADER) {
                connect();
        }
}
INSTANTIATE_SERIALIZE_METHODS(MidiInALSA);
REGISTER_POLYMORPHIC_INITIALIZER(Pluggable, MidiInALSA, "MidiInALSA");
 
 
// MidiSessionALSA ==========================================================
 
std::unique_ptr<MidiSessionALSA> MidiSessionALSA::instance;
 
void MidiSessionALSA::registerAll(
                PluggingController& controller, CliComm& cliComm,
                EventDistributor& eventDistributor, Scheduler& scheduler)
{
        if (!instance) {
                // Open the sequencer.
                snd_seq_t* seq;
                if (int err = snd_seq_open(&seq, "default", SND_SEQ_OPEN_DUPLEX, 0);
                    err < 0) {
                        cliComm.printError(
                                "Could not open sequencer: ", snd_strerror(err));
                        return;
                }
                snd_seq_set_client_name(seq, "openMSX");
                instance.reset(new MidiSessionALSA(*seq));
        }
        instance->scanClients(controller, eventDistributor, scheduler);
}
 
MidiSessionALSA::MidiSessionALSA(snd_seq_t& seq_)
        : seq(seq_)
{
}
 
MidiSessionALSA::~MidiSessionALSA()
{
        // While the Pluggables still have a copy of this pointer, they won't
        // be accessing it anymore when openMSX is exiting.
        snd_seq_close(&seq);
}
 
void MidiSessionALSA::scanClients(
        PluggingController& controller,
        EventDistributor& eventDistributor,
        Scheduler& scheduler)
{
        // Iterate through all clients.
        snd_seq_client_info_t* cInfo;
        snd_seq_client_info_alloca(&cInfo);
        snd_seq_client_info_set_client(cInfo, -1);
        while (snd_seq_query_next_client(&seq, cInfo) >= 0) {
                int client = snd_seq_client_info_get_client(cInfo);
                if (client == SND_SEQ_CLIENT_SYSTEM) {
                        continue;
                }
 
                // TODO: When there is more than one usable port per client,
                //       register them as separate pluggables.
                snd_seq_port_info_t* pInfo;
                snd_seq_port_info_alloca(&pInfo);
                snd_seq_port_info_set_client(pInfo, client);
                snd_seq_port_info_set_port(pInfo, -1);
                while (snd_seq_query_next_port(&seq, pInfo) >= 0) {
                        if (unsigned type = snd_seq_port_info_get_type(pInfo);
                            !(type & SND_SEQ_PORT_TYPE_MIDI_GENERIC)) {
                                continue;
                        }
                        constexpr unsigned wrCaps =
                                        SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE;
                        constexpr unsigned rdCaps =
                                        SND_SEQ_PORT_CAP_READ | SND_SEQ_PORT_CAP_SUBS_READ;
                        if ((snd_seq_port_info_get_capability(pInfo) & wrCaps) == wrCaps) {
                                controller.registerPluggable(std::make_unique<MidiOutALSA>(
                                                seq, *cInfo, *pInfo));
                        }
                        if ((snd_seq_port_info_get_capability(pInfo) & rdCaps) == rdCaps) {
                                controller.registerPluggable(std::make_unique<MidiInALSA>(
                                                eventDistributor, scheduler, seq, *cInfo, *pInfo));
                        }
                }
        }
}
 
} // namespace openmsx