Carla/source/backend/engine/CarlaEngineDummy.cpp

// SPDX-FileCopyrightText: 2011-2025 Filipe Coelho <falktx@falktx.com>
// SPDX-License-Identifier: GPL-2.0-or-later

#include "CarlaEngineGraph.hpp"
#include "CarlaEngineInit.hpp"
#include "CarlaEngineInternal.hpp"

#include "distrho/extra/Time.hpp"

CARLA_BACKEND_START_NAMESPACE

// -------------------------------------------------------------------------------------------------------------------
// Dummy Engine

class CarlaEngineDummy : public CarlaEngine,
                         public CarlaThread
{
public:
    CarlaEngineDummy()
        : CarlaEngine(),
          CarlaThread("CarlaEngineDummy"),
          fRunning(false)
    {
        carla_debug("CarlaEngineDummy::CarlaEngineDummy()");

        // just to make sure
        pData->options.transportMode = ENGINE_TRANSPORT_MODE_INTERNAL;
    }

    ~CarlaEngineDummy() override
    {
        carla_debug("CarlaEngineDummy::~CarlaEngineDummy()");
    }

    // -------------------------------------

    bool init(const char* const clientName) override
    {
        CARLA_SAFE_ASSERT_RETURN(clientName != nullptr && clientName[0] != '\0', false);
        carla_debug("CarlaEngineDummy::init(\"%s\")", clientName);

        if (pData->options.processMode != ENGINE_PROCESS_MODE_CONTINUOUS_RACK)
        {
            setLastError("Invalid process mode");
            return false;
        }

        fRunning = true;

        if (! pData->init(clientName))
        {
            close();
            setLastError("Failed to init internal data");
            return false;
        }

        pData->bufferSize = pData->options.audioBufferSize;
        pData->sampleRate = pData->options.audioSampleRate;
        pData->initTime(pData->options.transportExtra);

        pData->graph.create(2, 2, 0, 0);

        if (! startThread())
        {
            close();
            setLastError("Failed to start dummy audio thread");
            return false;
        }

        patchbayRefresh(true, false, false);

        callback(true, true,
                 ENGINE_CALLBACK_ENGINE_STARTED,
                 0,
                 pData->options.processMode,
                 pData->options.transportMode,
                 static_cast<int>(pData->bufferSize),
                 static_cast<float>(pData->sampleRate),
                 getCurrentDriverName());
        return true;
    }

    bool close() override
    {
        carla_debug("CarlaEngineDummy::close()");

        fRunning = false;
        stopThread(-1);
        CarlaEngine::close();

        pData->graph.destroy();
        return true;
    }

    bool hasIdleOnMainThread() const noexcept override
    {
        return true;
    }

    bool isRunning() const noexcept override
    {
        return fRunning;
    }

    bool isOffline() const noexcept override
    {
        return false;
    }

    EngineType getType() const noexcept override
    {
        return kEngineTypeDummy;
    }

    const char* getCurrentDriverName() const noexcept override
    {
        return "Dummy";
    }

    // -------------------------------------------------------------------
    // Patchbay

    bool patchbayRefresh(const bool sendHost, const bool sendOSC, const bool) override
    {
        CARLA_SAFE_ASSERT_RETURN(pData->graph.isReady(), false);

        RackGraph* const graph = pData->graph.getRackGraph();
        CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);

        ExternalGraph& extGraph(graph->extGraph);

        // ---------------------------------------------------------------
        // clear last ports

        extGraph.clear();

        // ---------------------------------------------------------------
        // fill in new ones

        {
            PortNameToId portNameToId;
            portNameToId.setData(kExternalGraphGroupAudioIn, 1, "capture_1", "");

            extGraph.audioPorts.ins.append(portNameToId);
        }

        {
            PortNameToId portNameToId;
            portNameToId.setData(kExternalGraphGroupAudioIn, 2, "capture_2", "");

            extGraph.audioPorts.ins.append(portNameToId);
        }

        {
            PortNameToId portNameToId;
            portNameToId.setData(kExternalGraphGroupAudioOut, 1, "playback_1", "");

            extGraph.audioPorts.outs.append(portNameToId);
        }

        {
            PortNameToId portNameToId;
            portNameToId.setData(kExternalGraphGroupAudioOut, 2, "playback_2", "");

            extGraph.audioPorts.outs.append(portNameToId);
        }

        // ---------------------------------------------------------------
        // now refresh

        if (sendHost || sendOSC)
            graph->refresh(sendHost, sendOSC, false, "Dummy");

        return true;
    }

    // -------------------------------------------------------------------

protected:
    void run() override
    {
        const uint32_t bufferSize = pData->bufferSize;
        const int64_t cycleTime = static_cast<int64_t>(
            static_cast<double>(bufferSize) / pData->sampleRate * 1000000 + 0.5);

        int delay = 0;
        if (const char* const delaystr = std::getenv("CARLA_BRIDGE_DUMMY"))
            if ((delay = atoi(delaystr)) == 1)
                delay = 0;

        carla_stdout("CarlaEngineDummy audio thread started, cycle time: " P_INT64 "ms, delay %ds",
                     cycleTime / 1000, delay);

        float* audioIns[2] = {
            (float*)std::malloc(sizeof(float)*bufferSize),
            (float*)std::malloc(sizeof(float)*bufferSize),
        };
        CARLA_SAFE_ASSERT_RETURN(audioIns[0] != nullptr,);
        CARLA_SAFE_ASSERT_RETURN(audioIns[1] != nullptr,);

        float* audioOuts[2] = {
            (float*)std::malloc(sizeof(float)*bufferSize),
            (float*)std::malloc(sizeof(float)*bufferSize),
        };
        CARLA_SAFE_ASSERT_RETURN(audioOuts[0] != nullptr,);
        CARLA_SAFE_ASSERT_RETURN(audioOuts[1] != nullptr,);

        carla_zeroFloats(audioIns[0], bufferSize);
        carla_zeroFloats(audioIns[1], bufferSize);
        carla_zeroStructs(pData->events.in,  kMaxEngineEventInternalCount);

        int64_t oldTime, newTime;

        while (! shouldThreadExit())
        {
            if (delay > 0)
                d_sleep(static_cast<uint>(delay));

            oldTime = d_gettime_us();

            const PendingRtEventsRunner prt(this, bufferSize, true);

            carla_zeroFloats(audioOuts[0], bufferSize);
            carla_zeroFloats(audioOuts[1], bufferSize);
            carla_zeroStructs(pData->events.out, kMaxEngineEventInternalCount);

            pData->graph.process(pData, audioIns, audioOuts, bufferSize);

            newTime = d_gettime_us();
            CARLA_SAFE_ASSERT_CONTINUE(newTime >= oldTime);

            const int64_t remainingTime = cycleTime - (newTime - oldTime);

            if (remainingTime <= 0)
            {
                ++pData->xruns;
                carla_stdout("XRUN! remaining time: " P_INT64 ", old: " P_INT64 ", new: " P_INT64 ")",
                             remainingTime, oldTime, newTime);
            }
            else if (remainingTime >= 1000)
            {
                CARLA_SAFE_ASSERT_CONTINUE(remainingTime < 1000000); // 1 sec
                d_msleep(static_cast<uint>(remainingTime / 1000));
            }
        }

        std::free(audioIns[0]);
        std::free(audioIns[1]);
        std::free(audioOuts[0]);
        std::free(audioOuts[1]);

        carla_stdout("CarlaEngineDummy audio thread finished with %u Xruns", pData->xruns);
    }

    // -------------------------------------------------------------------

private:
    bool fRunning;

    CARLA_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(CarlaEngineDummy)
};

// -----------------------------------------

namespace EngineInit {

CarlaEngine* newDummy()
{
    carla_debug("EngineInit::newDummy()");
    return new CarlaEngineDummy();
}

}

// -----------------------------------------

CARLA_BACKEND_END_NAMESPACE