path: root/alc/backends/jack.cpp

/**
 * OpenAL cross platform audio library
 * Copyright (C) 1999-2007 by authors.
 * This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 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
 *  Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the
 *  Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 * Or go to http://www.gnu.org/copyleft/lgpl.html
 */

#include "config.h"

#include "jack.h"

#include <array>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <memory.h>
#include <mutex>
#include <thread>
#include <functional>
#include <vector>

#include "albit.h"
#include "alc/alconfig.h"
#include "alnumeric.h"
#include "alsem.h"
#include "althrd_setname.h"
#include "core/device.h"
#include "core/helpers.h"
#include "core/logging.h"
#include "dynload.h"
#include "ringbuffer.h"

#include <jack/jack.h>
#include <jack/ringbuffer.h>


namespace {

#ifdef HAVE_DYNLOAD
#define JACK_FUNCS(MAGIC)          \
    MAGIC(jack_client_open);       \
    MAGIC(jack_client_close);      \
    MAGIC(jack_client_name_size);  \
    MAGIC(jack_get_client_name);   \
    MAGIC(jack_connect);           \
    MAGIC(jack_activate);          \
    MAGIC(jack_deactivate);        \
    MAGIC(jack_port_register);     \
    MAGIC(jack_port_unregister);   \
    MAGIC(jack_port_get_buffer);   \
    MAGIC(jack_port_name);         \
    MAGIC(jack_get_ports);         \
    MAGIC(jack_free);              \
    MAGIC(jack_get_sample_rate);   \
    MAGIC(jack_set_error_function); \
    MAGIC(jack_set_process_callback); \
    MAGIC(jack_set_buffer_size_callback); \
    MAGIC(jack_set_buffer_size);   \
    MAGIC(jack_get_buffer_size);

void *jack_handle;
#define MAKE_FUNC(f) decltype(f) * p##f
JACK_FUNCS(MAKE_FUNC)
decltype(jack_error_callback) * pjack_error_callback;
#undef MAKE_FUNC

#ifndef IN_IDE_PARSER
#define jack_client_open pjack_client_open
#define jack_client_close pjack_client_close
#define jack_client_name_size pjack_client_name_size
#define jack_get_client_name pjack_get_client_name
#define jack_connect pjack_connect
#define jack_activate pjack_activate
#define jack_deactivate pjack_deactivate
#define jack_port_register pjack_port_register
#define jack_port_unregister pjack_port_unregister
#define jack_port_get_buffer pjack_port_get_buffer
#define jack_port_name pjack_port_name
#define jack_get_ports pjack_get_ports
#define jack_free pjack_free
#define jack_get_sample_rate pjack_get_sample_rate
#define jack_set_error_function pjack_set_error_function
#define jack_set_process_callback pjack_set_process_callback
#define jack_set_buffer_size_callback pjack_set_buffer_size_callback
#define jack_set_buffer_size pjack_set_buffer_size
#define jack_get_buffer_size pjack_get_buffer_size
#define jack_error_callback (*pjack_error_callback)
#endif
#endif


/* NOLINTNEXTLINE(*-avoid-c-arrays) */
constexpr char JackDefaultAudioType[] = JACK_DEFAULT_AUDIO_TYPE;

jack_options_t ClientOptions = JackNullOption;

bool jack_load()
{
    bool error{false};

#ifdef HAVE_DYNLOAD
    if(!jack_handle)
    {
        std::string missing_funcs;

#ifdef _WIN32
#define JACKLIB "libjack.dll"
#else
#define JACKLIB "libjack.so.0"
#endif
        jack_handle = LoadLib(JACKLIB);
        if(!jack_handle)
        {
            WARN("Failed to load %s\n", JACKLIB);
            return false;
        }

        error = false;
#define LOAD_FUNC(f) do {                                                     \
    p##f = al::bit_cast<decltype(p##f)>(GetSymbol(jack_handle, #f));          \
    if(p##f == nullptr) {                                                     \
        error = true;                                                         \
        missing_funcs += "\n" #f;                                             \
    }                                                                         \
} while(0)
        JACK_FUNCS(LOAD_FUNC);
#undef LOAD_FUNC
        /* Optional symbols. These don't exist in all versions of JACK. */
#define LOAD_SYM(f) p##f = al::bit_cast<decltype(p##f)>(GetSymbol(jack_handle, #f))
        LOAD_SYM(jack_error_callback);
#undef LOAD_SYM

        if(error)
        {
            WARN("Missing expected functions:%s\n", missing_funcs.c_str());
            CloseLib(jack_handle);
            jack_handle = nullptr;
        }
    }
#endif

    return !error;
}


struct JackDeleter {
    void operator()(void *ptr) { jack_free(ptr); }
};
using JackPortsPtr = std::unique_ptr<const char*[],JackDeleter>; /* NOLINT(*-avoid-c-arrays) */

struct DeviceEntry {
    std::string mName;
    std::string mPattern;

    template<typename T, typename U>
    DeviceEntry(T&& name, U&& pattern)
        : mName{std::forward<T>(name)}, mPattern{std::forward<U>(pattern)}
    { }
};

std::vector<DeviceEntry> PlaybackList;


void EnumerateDevices(jack_client_t *client, std::vector<DeviceEntry> &list)
{
    std::remove_reference_t<decltype(list)>{}.swap(list);

    if(JackPortsPtr ports{jack_get_ports(client, nullptr, JackDefaultAudioType, JackPortIsInput)})
    {
        for(size_t i{0};ports[i];++i)
        {
            const char *sep{std::strchr(ports[i], ':')};
            if(!sep || ports[i] == sep) continue;

            const al::span<const char> portdev{ports[i], sep};
            auto check_name = [portdev](const DeviceEntry &entry) -> bool
            {
                const size_t len{portdev.size()};
                return entry.mName.length() == len
                    && entry.mName.compare(0, len, portdev.data(), len) == 0;
            };
            if(std::find_if(list.cbegin(), list.cend(), check_name) != list.cend())
                continue;

            std::string name{portdev.data(), portdev.size()};
            list.emplace_back(name, name+":");
            const auto &entry = list.back();
            TRACE("Got device: %s = %s\n", entry.mName.c_str(), entry.mPattern.c_str());
        }
        /* There are ports but couldn't get device names from them. Add a
         * generic entry.
         */
        if(ports[0] && list.empty())
        {
            WARN("No device names found in available ports, adding a generic name.\n");
            list.emplace_back("JACK", "");
        }
    }

    if(auto listopt = ConfigValueStr({}, "jack", "custom-devices"))
    {
        for(size_t strpos{0};strpos < listopt->size();)
        {
            size_t nextpos{listopt->find(';', strpos)};
            size_t seppos{listopt->find('=', strpos)};
            if(seppos >= nextpos || seppos == strpos)
            {
                const std::string entry{listopt->substr(strpos, nextpos-strpos)};
                ERR("Invalid device entry: \"%s\"\n", entry.c_str());
                if(nextpos != std::string::npos) ++nextpos;
                strpos = nextpos;
                continue;
            }

            const al::span<const char> name{listopt->data()+strpos, seppos-strpos};
            const al::span<const char> pattern{listopt->data()+(seppos+1),
                std::min(nextpos, listopt->size())-(seppos+1)};

            /* Check if this custom pattern already exists in the list. */
            auto check_pattern = [pattern](const DeviceEntry &entry) -> bool
            {
                const size_t len{pattern.size()};
                return entry.mPattern.length() == len
                    && entry.mPattern.compare(0, len, pattern.data(), len) == 0;
            };
            auto itemmatch = std::find_if(list.begin(), list.end(), check_pattern);
            if(itemmatch != list.end())
            {
                /* If so, replace the name with this custom one. */
                itemmatch->mName.assign(name.data(), name.size());
                TRACE("Customized device name: %s = %s\n", itemmatch->mName.c_str(),
                    itemmatch->mPattern.c_str());
            }
            else
            {
                /* Otherwise, add a new device entry. */
                list.emplace_back(std::string{name.data(), name.size()},
                    std::string{pattern.data(), pattern.size()});
                const auto &entry = list.back();
                TRACE("Got custom device: %s = %s\n", entry.mName.c_str(), entry.mPattern.c_str());
            }

            if(nextpos != std::string::npos) ++nextpos;
            strpos = nextpos;
        }
    }

    if(list.size() > 1)
    {
        /* Rename entries that have matching names, by appending '#2', '#3',
         * etc, as needed.
         */
        for(auto curitem = list.begin()+1;curitem != list.end();++curitem)
        {
            auto check_match = [curitem](const DeviceEntry &entry) -> bool
            { return entry.mName == curitem->mName; };
            if(std::find_if(list.begin(), curitem, check_match) != curitem)
            {
                std::string name{curitem->mName};
                size_t count{1};
                auto check_name = [&name](const DeviceEntry &entry) -> bool
                { return entry.mName == name; };
                do {
                    name = curitem->mName;
                    name += " #";
                    name += std::to_string(++count);
                } while(std::find_if(list.begin(), curitem, check_name) != curitem);
                curitem->mName = std::move(name);
            }
        }
    }
}


struct JackPlayback final : public BackendBase {
    JackPlayback(DeviceBase *device) noexcept : BackendBase{device} { }
    ~JackPlayback() override;

    int processRt(jack_nframes_t numframes) noexcept;
    static int processRtC(jack_nframes_t numframes, void *arg) noexcept
    { return static_cast<JackPlayback*>(arg)->processRt(numframes); }

    int process(jack_nframes_t numframes) noexcept;
    static int processC(jack_nframes_t numframes, void *arg) noexcept
    { return static_cast<JackPlayback*>(arg)->process(numframes); }

    int mixerProc();

    void open(std::string_view name) override;
    bool reset() override;
    void start() override;
    void stop() override;
    ClockLatency getClockLatency() override;

    std::string mPortPattern;

    jack_client_t *mClient{nullptr};
    std::array<jack_port_t*,MaxOutputChannels> mPort{};

    std::mutex mMutex;

    std::atomic<bool> mPlaying{false};
    bool mRTMixing{false};
    RingBufferPtr mRing;
    al::semaphore mSem;

    std::atomic<bool> mKillNow{true};
    std::thread mThread;
};

JackPlayback::~JackPlayback()
{
    if(!mClient)
        return;

    auto unregister_port = [this](jack_port_t *port) -> void
    { if(port) jack_port_unregister(mClient, port); };
    std::for_each(mPort.begin(), mPort.end(), unregister_port);
    mPort.fill(nullptr);

    jack_client_close(mClient);
    mClient = nullptr;
}


int JackPlayback::processRt(jack_nframes_t numframes) noexcept
{
    std::array<jack_default_audio_sample_t*,MaxOutputChannels> out;
    size_t numchans{0};
    for(auto port : mPort)
    {
        if(!port || numchans == mDevice->RealOut.Buffer.size())
            break;
        out[numchans++] = static_cast<float*>(jack_port_get_buffer(port, numframes));
    }

    if(mPlaying.load(std::memory_order_acquire)) LIKELY
        mDevice->renderSamples({out.data(), numchans}, static_cast<uint>(numframes));
    else
    {
        auto clear_buf = [numframes](float *outbuf) -> void
        { std::fill_n(outbuf, numframes, 0.0f); };
        std::for_each(out.begin(), out.begin()+numchans, clear_buf);
    }

    return 0;
}


int JackPlayback::process(jack_nframes_t numframes) noexcept
{
    std::array<jack_default_audio_sample_t*,MaxOutputChannels> out;
    size_t numchans{0};
    for(auto port : mPort)
    {
        if(!port) break;
        out[numchans++] = static_cast<float*>(jack_port_get_buffer(port, numframes));
    }

    jack_nframes_t total{0};
    if(mPlaying.load(std::memory_order_acquire)) LIKELY
    {
        auto data = mRing->getReadVector();
        jack_nframes_t todo{minu(numframes, static_cast<uint>(data.first.len))};
        auto write_first = [&data,numchans,todo](float *outbuf) -> float*
        {
            const float *RESTRICT in = reinterpret_cast<float*>(data.first.buf);
            auto deinterlace_input = [&in,numchans]() noexcept -> float
            {
                float ret{*in};
                in += numchans;
                return ret;
            };
            std::generate_n(outbuf, todo, deinterlace_input);
            data.first.buf += sizeof(float);
            return outbuf + todo;
        };
        std::transform(out.begin(), out.begin()+numchans, out.begin(), write_first);
        total += todo;

        todo = minu(numframes-total, static_cast<uint>(data.second.len));
        if(todo > 0)
        {
            auto write_second = [&data,numchans,todo](float *outbuf) -> float*
            {
                const float *RESTRICT in = reinterpret_cast<float*>(data.second.buf);
                auto deinterlace_input = [&in,numchans]() noexcept -> float
                {
                    float ret{*in};
                    in += numchans;
                    return ret;
                };
                std::generate_n(outbuf, todo, deinterlace_input);
                data.second.buf += sizeof(float);
                return outbuf + todo;
            };
            std::transform(out.begin(), out.begin()+numchans, out.begin(), write_second);
            total += todo;
        }

        mRing->readAdvance(total);
        mSem.post();
    }

    if(numframes > total)
    {
        const jack_nframes_t todo{numframes - total};
        auto clear_buf = [todo](float *outbuf) -> void { std::fill_n(outbuf, todo, 0.0f); };
        std::for_each(out.begin(), out.begin()+numchans, clear_buf);
    }

    return 0;
}

int JackPlayback::mixerProc()
{
    SetRTPriority();
    althrd_setname(MIXER_THREAD_NAME);

    const size_t frame_step{mDevice->channelsFromFmt()};

    while(!mKillNow.load(std::memory_order_acquire)
        && mDevice->Connected.load(std::memory_order_acquire))
    {
        if(mRing->writeSpace() < mDevice->UpdateSize)
        {
            mSem.wait();
            continue;
        }

        auto data = mRing->getWriteVector();
        size_t todo{data.first.len + data.second.len};
        todo -= todo%mDevice->UpdateSize;

        const auto len1 = static_cast<uint>(minz(data.first.len, todo));
        const auto len2 = static_cast<uint>(minz(data.second.len, todo-len1));

        std::lock_guard<std::mutex> _{mMutex};
        mDevice->renderSamples(data.first.buf, len1, frame_step);
        if(len2 > 0)
            mDevice->renderSamples(data.second.buf, len2, frame_step);
        mRing->writeAdvance(todo);
    }

    return 0;
}


void JackPlayback::open(std::string_view name)
{
    if(!mClient)
    {
        const PathNamePair &binname = GetProcBinary();
        const char *client_name{binname.fname.empty() ? "alsoft" : binname.fname.c_str()};

        jack_status_t status;
        mClient = jack_client_open(client_name, ClientOptions, &status, nullptr);
        if(mClient == nullptr)
            throw al::backend_exception{al::backend_error::DeviceError,
                "Failed to open client connection: 0x%02x", status};
        if((status&JackServerStarted))
            TRACE("JACK server started\n");
        if((status&JackNameNotUnique))
        {
            client_name = jack_get_client_name(mClient);
            TRACE("Client name not unique, got '%s' instead\n", client_name);
        }
    }

    if(PlaybackList.empty())
        EnumerateDevices(mClient, PlaybackList);

    if(name.empty() && !PlaybackList.empty())
    {
        name = PlaybackList[0].mName;
        mPortPattern = PlaybackList[0].mPattern;
    }
    else
    {
        auto check_name = [name](const DeviceEntry &entry) -> bool
        { return entry.mName == name; };
        auto iter = std::find_if(PlaybackList.cbegin(), PlaybackList.cend(), check_name);
        if(iter == PlaybackList.cend())
            throw al::backend_exception{al::backend_error::NoDevice,
                "Device name \"%.*s\" not found", static_cast<int>(name.length()), name.data()};
        mPortPattern = iter->mPattern;
    }

    mDevice->DeviceName = name;
}

bool JackPlayback::reset()
{
    auto unregister_port = [this](jack_port_t *port) -> void
    { if(port) jack_port_unregister(mClient, port); };
    std::for_each(mPort.begin(), mPort.end(), unregister_port);
    mPort.fill(nullptr);

    mRTMixing = GetConfigValueBool(mDevice->DeviceName, "jack", "rt-mix", true);
    jack_set_process_callback(mClient,
        mRTMixing ? &JackPlayback::processRtC : &JackPlayback::processC, this);

    /* Ignore the requested buffer metrics and just keep one JACK-sized buffer
     * ready for when requested.
     */
    mDevice->Frequency = jack_get_sample_rate(mClient);
    mDevice->UpdateSize = jack_get_buffer_size(mClient);
    if(mRTMixing)
    {
        /* Assume only two periods when directly mixing. Should try to query
         * the total port latency when connected.
         */
        mDevice->BufferSize = mDevice->UpdateSize * 2;
    }
    else
    {
        const std::string_view devname{mDevice->DeviceName};
        uint bufsize{ConfigValueUInt(devname, "jack", "buffer-size").value_or(mDevice->UpdateSize)};
        bufsize = maxu(NextPowerOf2(bufsize), mDevice->UpdateSize);
        mDevice->BufferSize = bufsize + mDevice->UpdateSize;
    }

    /* Force 32-bit float output. */
    mDevice->FmtType = DevFmtFloat;

    int port_num{0};
    auto ports_end = mPort.begin() + mDevice->channelsFromFmt();
    auto bad_port = mPort.begin();
    while(bad_port != ports_end)
    {
        std::string name{"channel_" + std::to_string(++port_num)};
        *bad_port = jack_port_register(mClient, name.c_str(), JackDefaultAudioType,
            JackPortIsOutput | JackPortIsTerminal, 0);
        if(!*bad_port) break;
        ++bad_port;
    }
    if(bad_port != ports_end)
    {
        ERR("Failed to register enough JACK ports for %s output\n",
            DevFmtChannelsString(mDevice->FmtChans));
        if(bad_port == mPort.begin()) return false;

        if(bad_port == mPort.begin()+1)
            mDevice->FmtChans = DevFmtMono;
        else
        {
            ports_end = mPort.begin()+2;
            while(bad_port != ports_end)
            {
                jack_port_unregister(mClient, *(--bad_port));
                *bad_port = nullptr;
            }
            mDevice->FmtChans = DevFmtStereo;
        }
    }

    setDefaultChannelOrder();

    return true;
}

void JackPlayback::start()
{
    if(jack_activate(mClient))
        throw al::backend_exception{al::backend_error::DeviceError, "Failed to activate client"};

    const std::string_view devname{mDevice->DeviceName};
    if(ConfigValueBool(devname, "jack", "connect-ports").value_or(true))
    {
        JackPortsPtr pnames{jack_get_ports(mClient, mPortPattern.c_str(), JackDefaultAudioType,
            JackPortIsInput)};
        if(!pnames)
        {
            jack_deactivate(mClient);
            throw al::backend_exception{al::backend_error::DeviceError, "No playback ports found"};
        }

        for(size_t i{0};i < std::size(mPort) && mPort[i];++i)
        {
            if(!pnames[i])
            {
                ERR("No physical playback port for \"%s\"\n", jack_port_name(mPort[i]));
                break;
            }
            if(jack_connect(mClient, jack_port_name(mPort[i]), pnames[i]))
                ERR("Failed to connect output port \"%s\" to \"%s\"\n", jack_port_name(mPort[i]),
                    pnames[i]);
        }
    }

    /* Reconfigure buffer metrics in case the server changed it since the reset
     * (it won't change again after jack_activate), then allocate the ring
     * buffer with the appropriate size.
     */
    mDevice->Frequency = jack_get_sample_rate(mClient);
    mDevice->UpdateSize = jack_get_buffer_size(mClient);
    mDevice->BufferSize = mDevice->UpdateSize * 2;

    mRing = nullptr;
    if(mRTMixing)
        mPlaying.store(true, std::memory_order_release);
    else
    {
        uint bufsize{ConfigValueUInt(devname, "jack", "buffer-size").value_or(mDevice->UpdateSize)};
        bufsize = maxu(NextPowerOf2(bufsize), mDevice->UpdateSize);
        mDevice->BufferSize = bufsize + mDevice->UpdateSize;

        mRing = RingBuffer::Create(bufsize, mDevice->frameSizeFromFmt(), true);

        try {
            mPlaying.store(true, std::memory_order_release);
            mKillNow.store(false, std::memory_order_release);
            mThread = std::thread{std::mem_fn(&JackPlayback::mixerProc), this};
        }
        catch(std::exception& e) {
            jack_deactivate(mClient);
            mPlaying.store(false, std::memory_order_release);
            throw al::backend_exception{al::backend_error::DeviceError,
                "Failed to start mixing thread: %s", e.what()};
        }
    }
}

void JackPlayback::stop()
{
    if(mPlaying.load(std::memory_order_acquire))
    {
        mKillNow.store(true, std::memory_order_release);
        if(mThread.joinable())
        {
            mSem.post();
            mThread.join();
        }

        jack_deactivate(mClient);
        mPlaying.store(false, std::memory_order_release);
    }
}


ClockLatency JackPlayback::getClockLatency()
{
    ClockLatency ret;

    std::lock_guard<std::mutex> _{mMutex};
    ret.ClockTime = mDevice->getClockTime();
    ret.Latency  = std::chrono::seconds{mRing ? mRing->readSpace() : mDevice->UpdateSize};
    ret.Latency /= mDevice->Frequency;

    return ret;
}


void jack_msg_handler(const char *message)
{
    WARN("%s\n", message);
}

} // namespace

bool JackBackendFactory::init()
{
    if(!jack_load())
        return false;

    if(!GetConfigValueBool({}, "jack", "spawn-server", false))
        ClientOptions = static_cast<jack_options_t>(ClientOptions | JackNoStartServer);

    const PathNamePair &binname = GetProcBinary();
    const char *client_name{binname.fname.empty() ? "alsoft" : binname.fname.c_str()};

    void (*old_error_cb)(const char*){&jack_error_callback ? jack_error_callback : nullptr};
    jack_set_error_function(jack_msg_handler);
    jack_status_t status;
    jack_client_t *client{jack_client_open(client_name, ClientOptions, &status, nullptr)};
    jack_set_error_function(old_error_cb);
    if(!client)
    {
        WARN("jack_client_open() failed, 0x%02x\n", status);
        if((status&JackServerFailed) && !(ClientOptions&JackNoStartServer))
            ERR("Unable to connect to JACK server\n");
        return false;
    }

    jack_client_close(client);
    return true;
}

bool JackBackendFactory::querySupport(BackendType type)
{ return (type == BackendType::Playback); }

std::string JackBackendFactory::probe(BackendType type)
{
    std::string outnames;
    auto append_name = [&outnames](const DeviceEntry &entry) -> void
    {
        /* Includes null char. */
        outnames.append(entry.mName.c_str(), entry.mName.length()+1);
    };

    const PathNamePair &binname = GetProcBinary();
    const char *client_name{binname.fname.empty() ? "alsoft" : binname.fname.c_str()};
    jack_status_t status;
    switch(type)
    {
    case BackendType::Playback:
        if(jack_client_t *client{jack_client_open(client_name, ClientOptions, &status, nullptr)})
        {
            EnumerateDevices(client, PlaybackList);
            jack_client_close(client);
        }
        else
            WARN("jack_client_open() failed, 0x%02x\n", status);
        std::for_each(PlaybackList.cbegin(), PlaybackList.cend(), append_name);
        break;
    case BackendType::Capture:
        break;
    }
    return outnames;
}

BackendPtr JackBackendFactory::createBackend(DeviceBase *device, BackendType type)
{
    if(type == BackendType::Playback)
        return BackendPtr{new JackPlayback{device}};
    return nullptr;
}

BackendFactory &JackBackendFactory::getFactory()
{
    static JackBackendFactory factory{};
    return factory;
}