JUCE/modules/juce_audio_devices/native/juce_win32_WASAPI.cpp

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2020 - Raw Material Software Limited

   JUCE is an open source library subject to commercial or open-source
   licensing.

   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wlanguage-extension-token")

#ifndef JUCE_WASAPI_LOGGING
 #define JUCE_WASAPI_LOGGING 0
#endif

//==============================================================================
namespace WasapiClasses
{

void logFailure (HRESULT hr)
{
    ignoreUnused (hr);
    jassert (hr != (HRESULT) 0x800401f0); // If you hit this, it means you're trying to call from
                                          // a thread which hasn't been initialised with CoInitialize().

   #if JUCE_WASAPI_LOGGING
    if (FAILED (hr))
    {
        const char* m = nullptr;

        switch (hr)
        {
            case E_POINTER:     m = "E_POINTER"; break;
            case E_INVALIDARG:  m = "E_INVALIDARG"; break;
            case E_NOINTERFACE: m = "E_NOINTERFACE"; break;

            #define JUCE_WASAPI_ERR(desc, n) \
                case MAKE_HRESULT(1, 0x889, n): m = #desc; break;

            JUCE_WASAPI_ERR (AUDCLNT_E_NOT_INITIALIZED, 0x001)
            JUCE_WASAPI_ERR (AUDCLNT_E_ALREADY_INITIALIZED, 0x002)
            JUCE_WASAPI_ERR (AUDCLNT_E_WRONG_ENDPOINT_TYPE, 0x003)
            JUCE_WASAPI_ERR (AUDCLNT_E_DEVICE_INVALIDATED, 0x004)
            JUCE_WASAPI_ERR (AUDCLNT_E_NOT_STOPPED, 0x005)
            JUCE_WASAPI_ERR (AUDCLNT_E_BUFFER_TOO_LARGE, 0x006)
            JUCE_WASAPI_ERR (AUDCLNT_E_OUT_OF_ORDER, 0x007)
            JUCE_WASAPI_ERR (AUDCLNT_E_UNSUPPORTED_FORMAT, 0x008)
            JUCE_WASAPI_ERR (AUDCLNT_E_INVALID_SIZE, 0x009)
            JUCE_WASAPI_ERR (AUDCLNT_E_DEVICE_IN_USE, 0x00a)
            JUCE_WASAPI_ERR (AUDCLNT_E_BUFFER_OPERATION_PENDING, 0x00b)
            JUCE_WASAPI_ERR (AUDCLNT_E_THREAD_NOT_REGISTERED, 0x00c)
            JUCE_WASAPI_ERR (AUDCLNT_E_EXCLUSIVE_MODE_NOT_ALLOWED, 0x00e)
            JUCE_WASAPI_ERR (AUDCLNT_E_ENDPOINT_CREATE_FAILED, 0x00f)
            JUCE_WASAPI_ERR (AUDCLNT_E_SERVICE_NOT_RUNNING, 0x010)
            JUCE_WASAPI_ERR (AUDCLNT_E_EVENTHANDLE_NOT_EXPECTED, 0x011)
            JUCE_WASAPI_ERR (AUDCLNT_E_EXCLUSIVE_MODE_ONLY, 0x012)
            JUCE_WASAPI_ERR (AUDCLNT_E_BUFDURATION_PERIOD_NOT_EQUAL, 0x013)
            JUCE_WASAPI_ERR (AUDCLNT_E_EVENTHANDLE_NOT_SET, 0x014)
            JUCE_WASAPI_ERR (AUDCLNT_E_INCORRECT_BUFFER_SIZE, 0x015)
            JUCE_WASAPI_ERR (AUDCLNT_E_BUFFER_SIZE_ERROR, 0x016)
            JUCE_WASAPI_ERR (AUDCLNT_E_CPUUSAGE_EXCEEDED, 0x017)
            JUCE_WASAPI_ERR (AUDCLNT_E_BUFFER_ERROR, 0x018)
            JUCE_WASAPI_ERR (AUDCLNT_E_BUFFER_SIZE_NOT_ALIGNED, 0x019)
            JUCE_WASAPI_ERR (AUDCLNT_E_INVALID_DEVICE_PERIOD, 0x020)
            default: break;
        }

        Logger::writeToLog ("WASAPI error: " + (m != nullptr ? String (m)
                                                             : String::toHexString ((int) hr)));
    }
   #endif
}

#undef check

bool check (HRESULT hr)
{
    logFailure (hr);
    return SUCCEEDED (hr);
}

//==============================================================================
}

#if JUCE_MINGW
 struct PROPERTYKEY
 {
    GUID fmtid;
    DWORD pid;
 };

 WINOLEAPI PropVariantClear (PROPVARIANT*);
#endif

#if JUCE_MINGW && defined (KSDATAFORMAT_SUBTYPE_PCM)
 #undef KSDATAFORMAT_SUBTYPE_PCM
 #undef KSDATAFORMAT_SUBTYPE_IEEE_FLOAT
#endif

#ifndef KSDATAFORMAT_SUBTYPE_PCM
 #define KSDATAFORMAT_SUBTYPE_PCM         uuidFromString ("00000001-0000-0010-8000-00aa00389b71")
 #define KSDATAFORMAT_SUBTYPE_IEEE_FLOAT  uuidFromString ("00000003-0000-0010-8000-00aa00389b71")
#endif

enum EDataFlow
{
    eRender = 0,
    eCapture = (eRender + 1),
    eAll = (eCapture + 1)
};

enum
{
    DEVICE_STATE_ACTIVE = 1
};

enum
{
    AUDCLNT_BUFFERFLAGS_DATA_DISCONTINUITY = 1,
    AUDCLNT_BUFFERFLAGS_SILENT = 2
};

JUCE_IUNKNOWNCLASS (IPropertyStore, "886d8eeb-8cf2-4446-8d02-cdba1dbdcf99")
{
    JUCE_COMCALL GetCount (DWORD*) = 0;
    JUCE_COMCALL GetAt (DWORD, PROPERTYKEY*) = 0;
    JUCE_COMCALL GetValue (const PROPERTYKEY&, PROPVARIANT*) = 0;
    JUCE_COMCALL SetValue (const PROPERTYKEY&, const PROPVARIANT&) = 0;
    JUCE_COMCALL Commit() = 0;
};

JUCE_IUNKNOWNCLASS (IMMDevice, "D666063F-1587-4E43-81F1-B948E807363F")
{
    JUCE_COMCALL Activate (REFIID, DWORD, PROPVARIANT*, void**) = 0;
    JUCE_COMCALL OpenPropertyStore (DWORD, IPropertyStore**) = 0;
    JUCE_COMCALL GetId (LPWSTR*) = 0;
    JUCE_COMCALL GetState (DWORD*) = 0;
};

JUCE_IUNKNOWNCLASS (IMMEndpoint, "1BE09788-6894-4089-8586-9A2A6C265AC5")
{
    JUCE_COMCALL GetDataFlow (EDataFlow*) = 0;
};

struct IMMDeviceCollection : public IUnknown
{
    JUCE_COMCALL GetCount (UINT*) = 0;
    JUCE_COMCALL Item (UINT, IMMDevice**) = 0;
};

enum ERole
{
    eConsole = 0,
    eMultimedia = (eConsole + 1),
    eCommunications = (eMultimedia + 1)
};

JUCE_IUNKNOWNCLASS (IMMNotificationClient, "7991EEC9-7E89-4D85-8390-6C703CEC60C0")
{
    JUCE_COMCALL OnDeviceStateChanged (LPCWSTR, DWORD) = 0;
    JUCE_COMCALL OnDeviceAdded (LPCWSTR) = 0;
    JUCE_COMCALL OnDeviceRemoved (LPCWSTR) = 0;
    JUCE_COMCALL OnDefaultDeviceChanged (EDataFlow, ERole, LPCWSTR) = 0;
    JUCE_COMCALL OnPropertyValueChanged (LPCWSTR, const PROPERTYKEY) = 0;
};

JUCE_IUNKNOWNCLASS (IMMDeviceEnumerator, "A95664D2-9614-4F35-A746-DE8DB63617E6")
{
    JUCE_COMCALL EnumAudioEndpoints (EDataFlow, DWORD, IMMDeviceCollection**) = 0;
    JUCE_COMCALL GetDefaultAudioEndpoint (EDataFlow, ERole, IMMDevice**) = 0;
    JUCE_COMCALL GetDevice (LPCWSTR, IMMDevice**) = 0;
    JUCE_COMCALL RegisterEndpointNotificationCallback (IMMNotificationClient*) = 0;
    JUCE_COMCALL UnregisterEndpointNotificationCallback (IMMNotificationClient*) = 0;
};

JUCE_COMCLASS (MMDeviceEnumerator, "BCDE0395-E52F-467C-8E3D-C4579291692E");

using REFERENCE_TIME = LONGLONG;

enum AVRT_PRIORITY
{
    AVRT_PRIORITY_LOW = -1,
    AVRT_PRIORITY_NORMAL,
    AVRT_PRIORITY_HIGH,
    AVRT_PRIORITY_CRITICAL
};

enum AUDCLNT_SHAREMODE
{
    AUDCLNT_SHAREMODE_SHARED,
    AUDCLNT_SHAREMODE_EXCLUSIVE
};

enum AUDIO_STREAM_CATEGORY
{
    AudioCategory_Other = 0,
    AudioCategory_ForegroundOnlyMedia,
    AudioCategory_BackgroundCapableMedia,
    AudioCategory_Communications,
    AudioCategory_Alerts,
    AudioCategory_SoundEffects,
    AudioCategory_GameEffects,
    AudioCategory_GameMedia,
    AudioCategory_GameChat,
    AudioCategory_Speech,
    AudioCategory_Movie,
    AudioCategory_Media
};

struct AudioClientProperties
{
    UINT32                  cbSize;
    BOOL                    bIsOffload;
    AUDIO_STREAM_CATEGORY   eCategory;
};

JUCE_IUNKNOWNCLASS (IAudioClient, "1CB9AD4C-DBFA-4c32-B178-C2F568A703B2")
{
    JUCE_COMCALL Initialize (AUDCLNT_SHAREMODE, DWORD, REFERENCE_TIME, REFERENCE_TIME, const WAVEFORMATEX*, LPCGUID) = 0;
    JUCE_COMCALL GetBufferSize (UINT32*) = 0;
    JUCE_COMCALL GetStreamLatency (REFERENCE_TIME*) = 0;
    JUCE_COMCALL GetCurrentPadding (UINT32*) = 0;
    JUCE_COMCALL IsFormatSupported (AUDCLNT_SHAREMODE, const WAVEFORMATEX*, WAVEFORMATEX**) = 0;
    JUCE_COMCALL GetMixFormat (WAVEFORMATEX**) = 0;
    JUCE_COMCALL GetDevicePeriod (REFERENCE_TIME*, REFERENCE_TIME*) = 0;
    JUCE_COMCALL Start() = 0;
    JUCE_COMCALL Stop() = 0;
    JUCE_COMCALL Reset() = 0;
    JUCE_COMCALL SetEventHandle (HANDLE) = 0;
    JUCE_COMCALL GetService (REFIID, void**) = 0;
};

JUCE_COMCLASS (IAudioClient2, "726778CD-F60A-4eda-82DE-E47610CD78AA") : public IAudioClient
{
    JUCE_COMCALL IsOffloadCapable (AUDIO_STREAM_CATEGORY, BOOL*) = 0;
    JUCE_COMCALL SetClientProperties (const AudioClientProperties*) = 0;
    JUCE_COMCALL GetBufferSizeLimits (const WAVEFORMATEX*, BOOL, REFERENCE_TIME*, REFERENCE_TIME*) = 0;
};

JUCE_COMCLASS (IAudioClient3, "1CB9AD4C-DBFA-4c32-B178-C2F568A703B2") : public IAudioClient2
{
    JUCE_COMCALL GetSharedModeEnginePeriod (const WAVEFORMATEX*, UINT32*, UINT32*, UINT32*, UINT32*) = 0;
    JUCE_COMCALL GetCurrentSharedModeEnginePeriod (WAVEFORMATEX**, UINT32*) = 0;
    JUCE_COMCALL InitializeSharedAudioStream (DWORD, UINT32, const WAVEFORMATEX*, LPCGUID) = 0;
};

JUCE_IUNKNOWNCLASS (IAudioCaptureClient, "C8ADBD64-E71E-48a0-A4DE-185C395CD317")
{
    JUCE_COMCALL GetBuffer (BYTE**, UINT32*, DWORD*, UINT64*, UINT64*) = 0;
    JUCE_COMCALL ReleaseBuffer (UINT32) = 0;
    JUCE_COMCALL GetNextPacketSize (UINT32*) = 0;
};

JUCE_IUNKNOWNCLASS (IAudioRenderClient, "F294ACFC-3146-4483-A7BF-ADDCA7C260E2")
{
    JUCE_COMCALL GetBuffer (UINT32, BYTE**) = 0;
    JUCE_COMCALL ReleaseBuffer (UINT32, DWORD) = 0;
};

JUCE_IUNKNOWNCLASS (IAudioEndpointVolume, "5CDF2C82-841E-4546-9722-0CF74078229A")
{
    JUCE_COMCALL RegisterControlChangeNotify (void*) = 0;
    JUCE_COMCALL UnregisterControlChangeNotify (void*) = 0;
    JUCE_COMCALL GetChannelCount (UINT*) = 0;
    JUCE_COMCALL SetMasterVolumeLevel (float, LPCGUID) = 0;
    JUCE_COMCALL SetMasterVolumeLevelScalar (float, LPCGUID) = 0;
    JUCE_COMCALL GetMasterVolumeLevel (float*) = 0;
    JUCE_COMCALL GetMasterVolumeLevelScalar (float*) = 0;
    JUCE_COMCALL SetChannelVolumeLevel (UINT, float, LPCGUID) = 0;
    JUCE_COMCALL SetChannelVolumeLevelScalar (UINT, float, LPCGUID) = 0;
    JUCE_COMCALL GetChannelVolumeLevel (UINT, float*) = 0;
    JUCE_COMCALL GetChannelVolumeLevelScalar (UINT, float*) = 0;
    JUCE_COMCALL SetMute (BOOL, LPCGUID) = 0;
    JUCE_COMCALL GetMute (BOOL*) = 0;
    JUCE_COMCALL GetVolumeStepInfo (UINT*, UINT*) = 0;
    JUCE_COMCALL VolumeStepUp (LPCGUID) = 0;
    JUCE_COMCALL VolumeStepDown (LPCGUID) = 0;
    JUCE_COMCALL QueryHardwareSupport (DWORD*) = 0;
    JUCE_COMCALL GetVolumeRange (float*, float*, float*) = 0;
};

enum AudioSessionDisconnectReason
{
    DisconnectReasonDeviceRemoval         = 0,
    DisconnectReasonServerShutdown        = 1,
    DisconnectReasonFormatChanged         = 2,
    DisconnectReasonSessionLogoff         = 3,
    DisconnectReasonSessionDisconnected   = 4,
    DisconnectReasonExclusiveModeOverride = 5
};

enum AudioSessionState
{
    AudioSessionStateInactive = 0,
    AudioSessionStateActive   = 1,
    AudioSessionStateExpired  = 2
};

JUCE_IUNKNOWNCLASS (IAudioSessionEvents, "24918ACC-64B3-37C1-8CA9-74A66E9957A8")
{
    JUCE_COMCALL OnDisplayNameChanged (LPCWSTR, LPCGUID) = 0;
    JUCE_COMCALL OnIconPathChanged (LPCWSTR, LPCGUID) = 0;
    JUCE_COMCALL OnSimpleVolumeChanged (float, BOOL, LPCGUID) = 0;
    JUCE_COMCALL OnChannelVolumeChanged (DWORD, float*, DWORD, LPCGUID) = 0;
    JUCE_COMCALL OnGroupingParamChanged (LPCGUID, LPCGUID) = 0;
    JUCE_COMCALL OnStateChanged (AudioSessionState) = 0;
    JUCE_COMCALL OnSessionDisconnected (AudioSessionDisconnectReason) = 0;
};

JUCE_IUNKNOWNCLASS (IAudioSessionControl, "F4B1A599-7266-4319-A8CA-E70ACB11E8CD")
{
    JUCE_COMCALL GetState (AudioSessionState*) = 0;
    JUCE_COMCALL GetDisplayName (LPWSTR*) = 0;
    JUCE_COMCALL SetDisplayName (LPCWSTR, LPCGUID) = 0;
    JUCE_COMCALL GetIconPath (LPWSTR*) = 0;
    JUCE_COMCALL SetIconPath (LPCWSTR, LPCGUID) = 0;
    JUCE_COMCALL GetGroupingParam (GUID*) = 0;
    JUCE_COMCALL SetGroupingParam (LPCGUID, LPCGUID) = 0;
    JUCE_COMCALL RegisterAudioSessionNotification (IAudioSessionEvents*) = 0;
    JUCE_COMCALL UnregisterAudioSessionNotification (IAudioSessionEvents*) = 0;
};

//==============================================================================
namespace WasapiClasses
{

String getDeviceID (IMMDevice* device)
{
    String s;
    WCHAR* deviceId = nullptr;

    if (check (device->GetId (&deviceId)))
    {
        s = String (deviceId);
        CoTaskMemFree (deviceId);
    }

    return s;
}

static EDataFlow getDataFlow (const ComSmartPtr<IMMDevice>& device)
{
    EDataFlow flow = eRender;
    if (auto endpoint = device.getInterface<IMMEndpoint>())
        (void) check (endpoint->GetDataFlow (&flow));

    return flow;
}

static int refTimeToSamples (const REFERENCE_TIME& t, double sampleRate) noexcept
{
    return roundToInt (sampleRate * ((double) t) * 0.0000001);
}

static REFERENCE_TIME samplesToRefTime (int numSamples, double sampleRate) noexcept
{
    return (REFERENCE_TIME) ((numSamples * 10000.0 * 1000.0 / sampleRate) + 0.5);
}

static void copyWavFormat (WAVEFORMATEXTENSIBLE& dest, const WAVEFORMATEX* src) noexcept
{
    memcpy (&dest, src, src->wFormatTag == WAVE_FORMAT_EXTENSIBLE ? sizeof (WAVEFORMATEXTENSIBLE)
                                                                  : sizeof (WAVEFORMATEX));
}

static bool isExclusiveMode (WASAPIDeviceMode deviceMode) noexcept
{
    return deviceMode == WASAPIDeviceMode::exclusive;
}

static bool isLowLatencyMode (WASAPIDeviceMode deviceMode) noexcept
{
    return deviceMode == WASAPIDeviceMode::sharedLowLatency;
}

static bool supportsSampleRateConversion (WASAPIDeviceMode deviceMode) noexcept
{
    return deviceMode == WASAPIDeviceMode::shared;
}

//==============================================================================
class WASAPIDeviceBase
{
public:
    WASAPIDeviceBase (const ComSmartPtr<IMMDevice>& d, WASAPIDeviceMode mode)
        : device (d),
          deviceMode (mode)
    {
        clientEvent = CreateEvent (nullptr, false, false, nullptr);

        ComSmartPtr<IAudioClient> tempClient (createClient());

        if (tempClient == nullptr)
            return;

        WAVEFORMATEXTENSIBLE format;

        if (! getClientMixFormat (tempClient, format))
            return;

        actualNumChannels = numChannels = format.Format.nChannels;
        defaultSampleRate = format.Format.nSamplesPerSec;
        rates.addUsingDefaultSort (defaultSampleRate);
        mixFormatChannelMask = format.dwChannelMask;

        if (isExclusiveMode (deviceMode))
            findSupportedFormat (tempClient, defaultSampleRate, mixFormatChannelMask, format);

        querySupportedBufferSizes (format, tempClient);
        querySupportedSampleRates (format, tempClient);
    }

    virtual ~WASAPIDeviceBase()
    {
        device = nullptr;
        CloseHandle (clientEvent);
    }

    bool isOk() const noexcept   { return defaultBufferSize > 0 && defaultSampleRate > 0; }

    bool openClient (const double newSampleRate, const BigInteger& newChannels, const int bufferSizeSamples)
    {
        sampleRate = newSampleRate;
        channels = newChannels;
        channels.setRange (actualNumChannels, channels.getHighestBit() + 1 - actualNumChannels, false);
        numChannels = channels.getHighestBit() + 1;

        if (numChannels == 0)
            return true;

        client = createClient();

        if (client != nullptr
             && tryInitialisingWithBufferSize (bufferSizeSamples))
        {
            sampleRateHasChanged = false;
            shouldShutdown = false;

            channelMaps.clear();

            for (int i = 0; i <= channels.getHighestBit(); ++i)
                if (channels[i])
                    channelMaps.add (i);

            REFERENCE_TIME latency;

            if (check (client->GetStreamLatency (&latency)))
                latencySamples = refTimeToSamples (latency, sampleRate);

            (void) check (client->GetBufferSize (&actualBufferSize));
            createSessionEventCallback();
            return check (client->SetEventHandle (clientEvent));
        }

        return false;
    }

    void closeClient()
    {
        if (client != nullptr)
            client->Stop();

        // N.B. this is needed to prevent a double-deletion of the IAudioSessionEvents object
        // on older versions of Windows
        Thread::sleep (5);

        deleteSessionEventCallback();
        client = nullptr;
        ResetEvent (clientEvent);
    }

    void deviceSampleRateChanged()
    {
        sampleRateHasChanged = true;
    }

    void deviceSessionBecameInactive()
    {
        isActive = false;
    }

    void deviceSessionExpired()
    {
        shouldShutdown = true;
    }

    void deviceSessionBecameActive()
    {
        isActive = true;
    }

    //==============================================================================
    ComSmartPtr<IMMDevice> device;
    ComSmartPtr<IAudioClient> client;

    WASAPIDeviceMode deviceMode;

    double sampleRate = 0, defaultSampleRate = 0;
    int numChannels = 0, actualNumChannels = 0;
    int minBufferSize = 0, defaultBufferSize = 0, latencySamples = 0;
    int lowLatencyBufferSizeMultiple = 0, lowLatencyMaxBufferSize = 0;
    DWORD mixFormatChannelMask = 0;
    Array<double> rates;
    HANDLE clientEvent = {};
    BigInteger channels;
    Array<int> channelMaps;
    UINT32 actualBufferSize = 0;
    int bytesPerSample = 0, bytesPerFrame = 0;
    std::atomic<bool> sampleRateHasChanged { false }, shouldShutdown { false }, isActive { true };

    virtual void updateFormat (bool isFloat) = 0;

private:
    //==============================================================================
    struct SessionEventCallback  : public ComBaseClassHelper<IAudioSessionEvents>
    {
        SessionEventCallback (WASAPIDeviceBase& d) : owner (d) {}

        JUCE_COMRESULT OnDisplayNameChanged (LPCWSTR, LPCGUID)                 { return S_OK; }
        JUCE_COMRESULT OnIconPathChanged (LPCWSTR, LPCGUID)                    { return S_OK; }
        JUCE_COMRESULT OnSimpleVolumeChanged (float, BOOL, LPCGUID)            { return S_OK; }
        JUCE_COMRESULT OnChannelVolumeChanged (DWORD, float*, DWORD, LPCGUID)  { return S_OK; }
        JUCE_COMRESULT OnGroupingParamChanged (LPCGUID, LPCGUID)               { return S_OK; }

        JUCE_COMRESULT OnStateChanged (AudioSessionState state)
        {
            switch (state)
            {
            case AudioSessionStateInactive:
                owner.deviceSessionBecameInactive();
                break;
            case AudioSessionStateExpired:
                owner.deviceSessionExpired();
                break;
            case AudioSessionStateActive:
                owner.deviceSessionBecameActive();
                break;
            }

            return S_OK;
        }

        JUCE_COMRESULT OnSessionDisconnected (AudioSessionDisconnectReason reason)
        {
            if (reason == DisconnectReasonFormatChanged)
                owner.deviceSampleRateChanged();

            return S_OK;
        }

        WASAPIDeviceBase& owner;
        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (SessionEventCallback)
    };

    ComSmartPtr<IAudioSessionControl> audioSessionControl;
    ComSmartPtr<SessionEventCallback> sessionEventCallback;

    void createSessionEventCallback()
    {
        deleteSessionEventCallback();
        client->GetService (__uuidof (IAudioSessionControl),
                            (void**) audioSessionControl.resetAndGetPointerAddress());

        if (audioSessionControl != nullptr)
        {
            sessionEventCallback = new SessionEventCallback (*this);
            audioSessionControl->RegisterAudioSessionNotification (sessionEventCallback);
            sessionEventCallback->Release(); // (required because ComBaseClassHelper objects are constructed with a ref count of 1)
        }
    }

    void deleteSessionEventCallback()
    {
        if (audioSessionControl != nullptr && sessionEventCallback != nullptr)
            audioSessionControl->UnregisterAudioSessionNotification (sessionEventCallback);

        audioSessionControl = nullptr;
        sessionEventCallback = nullptr;
    }

    //==============================================================================
    ComSmartPtr<IAudioClient> createClient()
    {
        ComSmartPtr<IAudioClient> newClient;

        if (device != nullptr)
            logFailure (device->Activate (__uuidof (IAudioClient), CLSCTX_INPROC_SERVER,
                                          nullptr, (void**) newClient.resetAndGetPointerAddress()));

        return newClient;
    }

    static bool getClientMixFormat (ComSmartPtr<IAudioClient>& client, WAVEFORMATEXTENSIBLE& format)
    {
        WAVEFORMATEX* mixFormat = nullptr;

        if (! check (client->GetMixFormat (&mixFormat)))
            return false;

        copyWavFormat (format, mixFormat);
        CoTaskMemFree (mixFormat);

        return true;
    }

    //==============================================================================
    void querySupportedBufferSizes (WAVEFORMATEXTENSIBLE format, ComSmartPtr<IAudioClient>& audioClient)
    {
        if (isLowLatencyMode (deviceMode))
        {
            if (auto audioClient3 = audioClient.getInterface<IAudioClient3>())
            {
                UINT32 defaultPeriod = 0, fundamentalPeriod = 0, minPeriod = 0, maxPeriod = 0;

                if (check (audioClient3->GetSharedModeEnginePeriod ((WAVEFORMATEX*) &format,
                                                                    &defaultPeriod,
                                                                    &fundamentalPeriod,
                                                                    &minPeriod,
                                                                    &maxPeriod)))
                {
                    minBufferSize = (int) minPeriod;
                    defaultBufferSize = (int) defaultPeriod;
                    lowLatencyMaxBufferSize = (int) maxPeriod;
                    lowLatencyBufferSizeMultiple = (int) fundamentalPeriod;
                }
            }
        }
        else
        {
            REFERENCE_TIME defaultPeriod, minPeriod;

            if (! check (audioClient->GetDevicePeriod (&defaultPeriod, &minPeriod)))
                return;

            minBufferSize = refTimeToSamples (minPeriod, defaultSampleRate);
            defaultBufferSize = refTimeToSamples (defaultPeriod, defaultSampleRate);
        }
    }

    void querySupportedSampleRates (WAVEFORMATEXTENSIBLE format, ComSmartPtr<IAudioClient>& audioClient)
    {
        for (auto rate : { 8000, 11025, 16000, 22050, 32000,
                           44100, 48000, 88200, 96000, 176400,
                           192000, 352800, 384000, 705600, 768000 })
        {
            if (rates.contains (rate))
                continue;

            format.Format.nSamplesPerSec  = (DWORD) rate;
            format.Format.nAvgBytesPerSec = (DWORD) (format.Format.nSamplesPerSec * format.Format.nChannels * format.Format.wBitsPerSample / 8);

            WAVEFORMATEX* nearestFormat = nullptr;

            if (SUCCEEDED (audioClient->IsFormatSupported (isExclusiveMode (deviceMode) ? AUDCLNT_SHAREMODE_EXCLUSIVE
                                                                                        : AUDCLNT_SHAREMODE_SHARED,
                                                           (WAVEFORMATEX*) &format,
                                                           isExclusiveMode (deviceMode) ? nullptr
                                                                                        : &nearestFormat)))
            {
                if (nearestFormat != nullptr)
                    rate = (int) nearestFormat->nSamplesPerSec;

                if (! rates.contains (rate))
                    rates.addUsingDefaultSort (rate);
            }

            CoTaskMemFree (nearestFormat);
        }
    }

    struct AudioSampleFormat
    {
        bool useFloat;
        int  bitsPerSampleToTry;
        int  bytesPerSampleContainer;
    };

    bool tryFormat (const AudioSampleFormat sampleFormat, IAudioClient* clientToUse, double newSampleRate,
                    DWORD newMixFormatChannelMask, WAVEFORMATEXTENSIBLE& format) const
    {
        zerostruct (format);

        if (numChannels <= 2 && sampleFormat.bitsPerSampleToTry <= 16)
        {
            format.Format.wFormatTag = WAVE_FORMAT_PCM;
        }
        else
        {
            format.Format.wFormatTag = WAVE_FORMAT_EXTENSIBLE;
            format.Format.cbSize = sizeof (WAVEFORMATEXTENSIBLE) - sizeof (WAVEFORMATEX);
        }

        format.Format.nSamplesPerSec       = (DWORD) newSampleRate;
        format.Format.nChannels            = (WORD) numChannels;
        format.Format.wBitsPerSample       = (WORD) (8 * sampleFormat.bytesPerSampleContainer);
        format.Samples.wValidBitsPerSample = (WORD) (sampleFormat.bitsPerSampleToTry);
        format.Format.nBlockAlign          = (WORD) (format.Format.nChannels * format.Format.wBitsPerSample / 8);
        format.Format.nAvgBytesPerSec      = (DWORD) (format.Format.nSamplesPerSec * format.Format.nBlockAlign);
        format.SubFormat                   = sampleFormat.useFloat ? KSDATAFORMAT_SUBTYPE_IEEE_FLOAT : KSDATAFORMAT_SUBTYPE_PCM;
        format.dwChannelMask               = newMixFormatChannelMask;

        WAVEFORMATEX* nearestFormat = nullptr;

        HRESULT hr = clientToUse->IsFormatSupported (isExclusiveMode (deviceMode) ? AUDCLNT_SHAREMODE_EXCLUSIVE
                                                                                  : AUDCLNT_SHAREMODE_SHARED,
                                                     (WAVEFORMATEX*) &format,
                                                     isExclusiveMode (deviceMode) ? nullptr
                                                                                  : &nearestFormat);
        logFailure (hr);

        auto supportsSRC = supportsSampleRateConversion (deviceMode);

        if (hr == S_FALSE
            && nearestFormat != nullptr
            && (format.Format.nSamplesPerSec == nearestFormat->nSamplesPerSec
                || supportsSRC))
        {
            copyWavFormat (format, nearestFormat);

            if (supportsSRC)
            {
                format.Format.nSamplesPerSec  = (DWORD) newSampleRate;
                format.Format.nAvgBytesPerSec = (DWORD) (format.Format.nSamplesPerSec * format.Format.nBlockAlign);
            }

            hr = S_OK;
        }

        CoTaskMemFree (nearestFormat);
        return hr == S_OK;
    }

    bool findSupportedFormat (IAudioClient* clientToUse, double newSampleRate,
                              DWORD newMixFormatChannelMask, WAVEFORMATEXTENSIBLE& format) const
    {
        static const AudioSampleFormat formats[] =
        {
            { true,  32, 4 },
            { false, 32, 4 },
            { false, 24, 4 },
            { false, 24, 3 },
            { false, 20, 4 },
            { false, 20, 3 },
            { false, 16, 2 }
        };

        for (int i = 0; i < numElementsInArray (formats); ++i)
            if (tryFormat (formats[i], clientToUse, newSampleRate, newMixFormatChannelMask, format))
                return true;

        return false;
    }

    DWORD getStreamFlags()
    {
        DWORD streamFlags = 0x40000; /*AUDCLNT_STREAMFLAGS_EVENTCALLBACK*/

        if (supportsSampleRateConversion (deviceMode))
            streamFlags |= (0x80000000    /*AUDCLNT_STREAMFLAGS_AUTOCONVERTPCM*/
                            | 0x8000000); /*AUDCLNT_STREAMFLAGS_SRC_DEFAULT_QUALITY*/

        return streamFlags;
    }

    bool initialiseLowLatencyClient (int bufferSizeSamples, WAVEFORMATEXTENSIBLE format)
    {
        if (auto audioClient3 = client.getInterface<IAudioClient3>())
            return check (audioClient3->InitializeSharedAudioStream (getStreamFlags(),
                                                                     (UINT32) bufferSizeSamples,
                                                                     (WAVEFORMATEX*) &format,
                                                                     nullptr));

        return false;
    }

    bool initialiseStandardClient (int bufferSizeSamples, WAVEFORMATEXTENSIBLE format)
    {
        REFERENCE_TIME defaultPeriod = 0, minPeriod = 0;

        check (client->GetDevicePeriod (&defaultPeriod, &minPeriod));

        if (isExclusiveMode (deviceMode) && bufferSizeSamples > 0)
            defaultPeriod = jmax (minPeriod, samplesToRefTime (bufferSizeSamples, format.Format.nSamplesPerSec));

        for (;;)
        {
            GUID session;
            auto hr = client->Initialize (isExclusiveMode (deviceMode) ? AUDCLNT_SHAREMODE_EXCLUSIVE
                                                                       : AUDCLNT_SHAREMODE_SHARED,
                                          getStreamFlags(),
                                          defaultPeriod,
                                          isExclusiveMode (deviceMode) ? defaultPeriod : 0,
                                          (WAVEFORMATEX*) &format,
                                          &session);

            if (check (hr))
                return true;

            // Handle the "alignment dance" : http://msdn.microsoft.com/en-us/library/windows/desktop/dd370875(v=vs.85).aspx (see Remarks)
            if (hr != MAKE_HRESULT (1, 0x889, 0x19)) // AUDCLNT_E_BUFFER_SIZE_NOT_ALIGNED
                break;

            UINT32 numFrames = 0;
            if (! check (client->GetBufferSize (&numFrames)))
                break;

            // Recreate client
            client = nullptr;
            client = createClient();

            defaultPeriod = samplesToRefTime ((int) numFrames, format.Format.nSamplesPerSec);
        }

        return false;
    }

    bool tryInitialisingWithBufferSize (int bufferSizeSamples)
    {
        WAVEFORMATEXTENSIBLE format;

        if (findSupportedFormat (client, sampleRate, mixFormatChannelMask, format))
        {
            auto isInitialised = isLowLatencyMode (deviceMode) ? initialiseLowLatencyClient (bufferSizeSamples, format)
                                                               : initialiseStandardClient   (bufferSizeSamples, format);

            if (isInitialised)
            {
                actualNumChannels  = format.Format.nChannels;
                const bool isFloat = format.Format.wFormatTag == WAVE_FORMAT_EXTENSIBLE && format.SubFormat == KSDATAFORMAT_SUBTYPE_IEEE_FLOAT;
                bytesPerSample     = format.Format.wBitsPerSample / 8;
                bytesPerFrame      = format.Format.nBlockAlign;

                updateFormat (isFloat);

                return true;
            }
        }

        return false;
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (WASAPIDeviceBase)
};

//==============================================================================
class WASAPIInputDevice  : public WASAPIDeviceBase
{
public:
    WASAPIInputDevice (const ComSmartPtr<IMMDevice>& d, WASAPIDeviceMode mode)
        : WASAPIDeviceBase (d, mode)
    {
    }

    ~WASAPIInputDevice() override
    {
        close();
    }

    bool open (double newSampleRate, const BigInteger& newChannels, int bufferSizeSamples)
    {
        return openClient (newSampleRate, newChannels, bufferSizeSamples)
                && (numChannels == 0 || check (client->GetService (__uuidof (IAudioCaptureClient),
                                                                   (void**) captureClient.resetAndGetPointerAddress())));
    }

    void close()
    {
        closeClient();
        captureClient = nullptr;
        reservoir.reset();
        reservoirReadPos = 0;
        reservoirWritePos = 0;
    }

    template <class SourceType>
    void updateFormatWithType (SourceType*) noexcept
    {
        using NativeType = AudioData::Pointer<AudioData::Float32, AudioData::NativeEndian, AudioData::NonInterleaved, AudioData::NonConst>;
        converter.reset (new AudioData::ConverterInstance<AudioData::Pointer<SourceType, AudioData::LittleEndian, AudioData::Interleaved, AudioData::Const>, NativeType> (actualNumChannels, 1));
    }

    void updateFormat (bool isFloat) override
    {
        if (isFloat)                    updateFormatWithType ((AudioData::Float32*) nullptr);
        else if (bytesPerSample == 4)   updateFormatWithType ((AudioData::Int32*)   nullptr);
        else if (bytesPerSample == 3)   updateFormatWithType ((AudioData::Int24*)   nullptr);
        else                            updateFormatWithType ((AudioData::Int16*)   nullptr);
    }

    bool start (int userBufferSize)
    {
        reservoirSize = (int) (actualBufferSize + (UINT32) userBufferSize);
        reservoirMask = nextPowerOfTwo (reservoirSize) - 1;
        reservoir.setSize ((size_t) ((reservoirMask + 1) * bytesPerFrame), true);
        reservoirReadPos = 0;
        reservoirWritePos = 0;
        xruns = 0;

        if (! check (client->Start()))
            return false;

        purgeInputBuffers();
        isActive = true;

        return true;
    }

    void purgeInputBuffers()
    {
        uint8* inputData;
        UINT32 numSamplesAvailable;
        DWORD flags;

        while (captureClient->GetBuffer (&inputData, &numSamplesAvailable, &flags, nullptr, nullptr)
                  != MAKE_HRESULT (0, 0x889, 0x1) /* AUDCLNT_S_BUFFER_EMPTY */)
            captureClient->ReleaseBuffer (numSamplesAvailable);
    }

    int getNumSamplesInReservoir() const noexcept    { return reservoirWritePos.load() - reservoirReadPos.load(); }

    void handleDeviceBuffer()
    {
        if (numChannels <= 0)
            return;

        uint8* inputData;
        UINT32 numSamplesAvailable;
        DWORD flags;

        while (check (captureClient->GetBuffer (&inputData, &numSamplesAvailable, &flags, nullptr, nullptr)) && numSamplesAvailable > 0)
        {
            if ((flags & AUDCLNT_BUFFERFLAGS_DATA_DISCONTINUITY) != 0)
                xruns++;

            int samplesLeft = (int) numSamplesAvailable;

            while (samplesLeft > 0)
            {
                auto localWrite = reservoirWritePos.load() & reservoirMask;
                auto samplesToDo = jmin (samplesLeft, reservoirMask + 1 - localWrite);
                auto samplesToDoBytes = samplesToDo * bytesPerFrame;

                void* reservoirPtr = addBytesToPointer (reservoir.getData(), localWrite * bytesPerFrame);

                if ((flags & AUDCLNT_BUFFERFLAGS_SILENT) != 0)
                    zeromem (reservoirPtr, (size_t) samplesToDoBytes);
                else
                    memcpy (reservoirPtr, inputData, (size_t) samplesToDoBytes);

                reservoirWritePos += samplesToDo;
                inputData += samplesToDoBytes;
                samplesLeft -= samplesToDo;
            }

            if (getNumSamplesInReservoir() > reservoirSize)
                reservoirReadPos = reservoirWritePos.load() - reservoirSize;

            captureClient->ReleaseBuffer (numSamplesAvailable);
        }
    }

    void copyBuffersFromReservoir (float** destBuffers, int numDestBuffers, int bufferSize)
    {
        if ((numChannels <= 0 && bufferSize == 0) || reservoir.isEmpty())
            return;

        int offset = jmax (0, bufferSize - getNumSamplesInReservoir());

        if (offset > 0)
        {
            for (int i = 0; i < numDestBuffers; ++i)
                zeromem (destBuffers[i], (size_t) offset * sizeof (float));

            bufferSize -= offset;
            reservoirReadPos -= offset / 2;
        }

        while (bufferSize > 0)
        {
            auto localRead = reservoirReadPos.load() & reservoirMask;
            auto samplesToDo = jmin (bufferSize, getNumSamplesInReservoir(), reservoirMask + 1 - localRead);

            if (samplesToDo <= 0)
                break;

            auto reservoirOffset = localRead * bytesPerFrame;

            for (int i = 0; i < numDestBuffers; ++i)
                converter->convertSamples (destBuffers[i] + offset, 0, addBytesToPointer (reservoir.getData(), reservoirOffset), channelMaps.getUnchecked(i), samplesToDo);

            bufferSize -= samplesToDo;
            offset += samplesToDo;
            reservoirReadPos += samplesToDo;
        }
    }

    ComSmartPtr<IAudioCaptureClient> captureClient;
    MemoryBlock reservoir;
    int reservoirSize, reservoirMask, xruns;
    std::atomic<int> reservoirReadPos, reservoirWritePos;

    std::unique_ptr<AudioData::Converter> converter;

private:
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (WASAPIInputDevice)
};

//==============================================================================
class WASAPIOutputDevice  : public WASAPIDeviceBase
{
public:
    WASAPIOutputDevice (const ComSmartPtr<IMMDevice>& d, WASAPIDeviceMode mode)
        : WASAPIDeviceBase (d, mode)
    {
    }

    ~WASAPIOutputDevice() override
    {
        close();
    }

    bool open (double newSampleRate, const BigInteger& newChannels, int bufferSizeSamples)
    {
        return openClient (newSampleRate, newChannels, bufferSizeSamples)
                && (numChannels == 0 || check (client->GetService (__uuidof (IAudioRenderClient),
                                                                   (void**) renderClient.resetAndGetPointerAddress())));
    }

    void close()
    {
        closeClient();
        renderClient = nullptr;
    }

    template <class DestType>
    void updateFormatWithType (DestType*)
    {
        using NativeType = AudioData::Pointer<AudioData::Float32, AudioData::NativeEndian, AudioData::NonInterleaved, AudioData::Const>;
        converter.reset (new AudioData::ConverterInstance<NativeType, AudioData::Pointer<DestType, AudioData::LittleEndian, AudioData::Interleaved, AudioData::NonConst>> (1, actualNumChannels));
    }

    void updateFormat (bool isFloat) override
    {
        if (isFloat)                    updateFormatWithType ((AudioData::Float32*) nullptr);
        else if (bytesPerSample == 4)   updateFormatWithType ((AudioData::Int32*)   nullptr);
        else if (bytesPerSample == 3)   updateFormatWithType ((AudioData::Int24*)   nullptr);
        else                            updateFormatWithType ((AudioData::Int16*)   nullptr);
    }

    bool start()
    {
        auto samplesToDo = getNumSamplesAvailableToCopy();
        uint8* outputData;

        if (check (renderClient->GetBuffer ((UINT32) samplesToDo, &outputData)))
            renderClient->ReleaseBuffer ((UINT32) samplesToDo, AUDCLNT_BUFFERFLAGS_SILENT);

        if (! check (client->Start()))
            return false;

        isActive = true;

        return true;
    }

    int getNumSamplesAvailableToCopy() const
    {
        if (numChannels <= 0)
            return 0;

        if (! isExclusiveMode (deviceMode))
        {
            UINT32 padding = 0;

            if (check (client->GetCurrentPadding (&padding)))
                return (int) actualBufferSize - (int) padding;
        }

        return (int) actualBufferSize;
    }

    void copyBuffers (const float** srcBuffers, int numSrcBuffers, int bufferSize,
                      WASAPIInputDevice* inputDevice, Thread& thread)
    {
        if (numChannels <= 0)
            return;

        int offset = 0;

        while (bufferSize > 0)
        {
            // This is needed in order not to drop any input data if the output device endpoint buffer was full
            if ((! isExclusiveMode (deviceMode)) && inputDevice != nullptr
                  && WaitForSingleObject (inputDevice->clientEvent, 0) == WAIT_OBJECT_0)
                inputDevice->handleDeviceBuffer();

            int samplesToDo = jmin (getNumSamplesAvailableToCopy(), bufferSize);

            if (samplesToDo == 0)
            {
                // This can ONLY occur in non-exclusive mode
                if (! thread.threadShouldExit() && WaitForSingleObject (clientEvent, 1000) == WAIT_OBJECT_0)
                    continue;

                break;
            }

            if (isExclusiveMode (deviceMode) && WaitForSingleObject (clientEvent, 1000) == WAIT_TIMEOUT)
                break;

            uint8* outputData = nullptr;
            if (check (renderClient->GetBuffer ((UINT32) samplesToDo, &outputData)))
            {
                for (int i = 0; i < numSrcBuffers; ++i)
                    converter->convertSamples (outputData, channelMaps.getUnchecked(i), srcBuffers[i] + offset, 0, samplesToDo);

                renderClient->ReleaseBuffer ((UINT32) samplesToDo, 0);
            }

            bufferSize -= samplesToDo;
            offset += samplesToDo;
        }
    }

    ComSmartPtr<IAudioRenderClient> renderClient;
    std::unique_ptr<AudioData::Converter> converter;

private:
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (WASAPIOutputDevice)
};

//==============================================================================
class WASAPIAudioIODevice  : public AudioIODevice,
                             public Thread,
                             private AsyncUpdater
{
public:
    WASAPIAudioIODevice (const String& deviceName,
                         const String& typeNameIn,
                         const String& outputDeviceID,
                         const String& inputDeviceID,
                         WASAPIDeviceMode mode)
        : AudioIODevice (deviceName, typeNameIn),
          Thread ("JUCE WASAPI"),
          outputDeviceId (outputDeviceID),
          inputDeviceId (inputDeviceID),
          deviceMode (mode)
    {
    }

    ~WASAPIAudioIODevice() override
    {
        cancelPendingUpdate();
        close();
    }

    bool initialise()
    {
        latencyIn = latencyOut = 0;
        Array<double> ratesIn, ratesOut;

        if (createDevices())
        {
            jassert (inputDevice != nullptr || outputDevice != nullptr);

            sampleRates.clear();

            if (inputDevice != nullptr && outputDevice != nullptr)
            {
                defaultSampleRate = jmin (inputDevice->defaultSampleRate, outputDevice->defaultSampleRate);
                minBufferSize = jmax (inputDevice->minBufferSize, outputDevice->minBufferSize);
                defaultBufferSize = jmax (inputDevice->defaultBufferSize, outputDevice->defaultBufferSize);

                if (isLowLatencyMode (deviceMode))
                {
                    lowLatencyMaxBufferSize = jmin (inputDevice->lowLatencyMaxBufferSize, outputDevice->lowLatencyMaxBufferSize);
                    lowLatencyBufferSizeMultiple = jmax (inputDevice->lowLatencyBufferSizeMultiple, outputDevice->lowLatencyBufferSizeMultiple);
                }

                sampleRates.addArray (inputDevice->rates);

                if (supportsSampleRateConversion (deviceMode))
                {
                    for (auto r : outputDevice->rates)
                        if (! sampleRates.contains (r))
                            sampleRates.addUsingDefaultSort (r);
                }
                else
                {
                    sampleRates.removeValuesNotIn (outputDevice->rates);
                }
            }
            else
            {
                auto* d = inputDevice != nullptr ? static_cast<WASAPIDeviceBase*> (inputDevice.get())
                                                 : static_cast<WASAPIDeviceBase*> (outputDevice.get());

                defaultSampleRate = d->defaultSampleRate;
                minBufferSize = d->minBufferSize;
                defaultBufferSize = d->defaultBufferSize;

                if (isLowLatencyMode (deviceMode))
                {
                    lowLatencyMaxBufferSize = d->lowLatencyMaxBufferSize;
                    lowLatencyBufferSizeMultiple = d->lowLatencyBufferSizeMultiple;
                }

                sampleRates = d->rates;
            }

            bufferSizes.clear();
            bufferSizes.addUsingDefaultSort (defaultBufferSize);

            if (minBufferSize != defaultBufferSize)
                bufferSizes.addUsingDefaultSort (minBufferSize);

            if (isLowLatencyMode (deviceMode))
            {
                auto size = minBufferSize;

                while (size < lowLatencyMaxBufferSize)
                {
                    size += lowLatencyBufferSizeMultiple;

                    if (! bufferSizes.contains (size))
                        bufferSizes.addUsingDefaultSort (size);
                }
            }
            else
            {
                int n = 64;
                for (int i = 0; i < 40; ++i)
                {
                    if (n >= minBufferSize && n <= 2048 && ! bufferSizes.contains (n))
                        bufferSizes.addUsingDefaultSort (n);

                    n += (n < 512) ? 32 : (n < 1024 ? 64 : 128);
                }
            }

            return true;
        }

        return false;
    }

    StringArray getOutputChannelNames() override
    {
        StringArray outChannels;

        if (outputDevice != nullptr)
            for (int i = 1; i <= outputDevice->actualNumChannels; ++i)
                outChannels.add ("Output channel " + String (i));

        return outChannels;
    }

    StringArray getInputChannelNames() override
    {
        StringArray inChannels;

        if (inputDevice != nullptr)
            for (int i = 1; i <= inputDevice->actualNumChannels; ++i)
                inChannels.add ("Input channel " + String (i));

        return inChannels;
    }

    Array<double> getAvailableSampleRates() override        { return sampleRates; }
    Array<int> getAvailableBufferSizes() override           { return bufferSizes; }
    int getDefaultBufferSize() override                     { return defaultBufferSize; }

    int getCurrentBufferSizeSamples() override              { return currentBufferSizeSamples; }
    double getCurrentSampleRate() override                  { return currentSampleRate; }
    int getCurrentBitDepth() override                       { return 32; }
    int getOutputLatencyInSamples() override                { return latencyOut; }
    int getInputLatencyInSamples() override                 { return latencyIn; }
    BigInteger getActiveOutputChannels() const override     { return outputDevice != nullptr ? outputDevice->channels : BigInteger(); }
    BigInteger getActiveInputChannels() const override      { return inputDevice  != nullptr ? inputDevice->channels  : BigInteger(); }
    String getLastError() override                          { return lastError; }
    int getXRunCount() const noexcept override              { return inputDevice != nullptr ? inputDevice->xruns : -1; }

    String open (const BigInteger& inputChannels, const BigInteger& outputChannels,
                 double sampleRate, int bufferSizeSamples) override
    {
        close();
        lastError.clear();

        if (sampleRates.size() == 0 && inputDevice != nullptr && outputDevice != nullptr)
        {
            lastError = TRANS("The input and output devices don't share a common sample rate!");
            return lastError;
        }

        currentBufferSizeSamples  = bufferSizeSamples <= 0 ? defaultBufferSize : jmax (bufferSizeSamples, minBufferSize);
        currentSampleRate         = sampleRate > 0 ? sampleRate : defaultSampleRate;
        lastKnownInputChannels    = inputChannels;
        lastKnownOutputChannels   = outputChannels;

        if (inputDevice != nullptr && ! inputDevice->open (currentSampleRate, inputChannels, bufferSizeSamples))
        {
            lastError = TRANS("Couldn't open the input device!");
            return lastError;
        }

        if (outputDevice != nullptr && ! outputDevice->open (currentSampleRate, outputChannels, bufferSizeSamples))
        {
            close();
            lastError = TRANS("Couldn't open the output device!");
            return lastError;
        }

        if (isExclusiveMode (deviceMode))
        {
            // This is to make sure that the callback uses actualBufferSize in case of exclusive mode
            if (inputDevice != nullptr && outputDevice != nullptr && inputDevice->actualBufferSize != outputDevice->actualBufferSize)
            {
                close();
                lastError = TRANS("Couldn't open the output device (buffer size mismatch)");
                return lastError;
            }

            currentBufferSizeSamples = (int) (outputDevice != nullptr ? outputDevice->actualBufferSize
                                                                      : inputDevice->actualBufferSize);
        }

        if (inputDevice != nullptr)   ResetEvent (inputDevice->clientEvent);
        if (outputDevice != nullptr)  ResetEvent (outputDevice->clientEvent);

        shouldShutdown = false;
        deviceSampleRateChanged = false;

        startThread (8);
        Thread::sleep (5);

        if (inputDevice != nullptr && inputDevice->client != nullptr)
        {
            latencyIn = (int) (inputDevice->latencySamples + currentBufferSizeSamples);

            if (! inputDevice->start (currentBufferSizeSamples))
            {
                close();
                lastError = TRANS("Couldn't start the input device!");
                return lastError;
            }
        }

        if (outputDevice != nullptr && outputDevice->client != nullptr)
        {
            latencyOut = (int) (outputDevice->latencySamples + currentBufferSizeSamples);

            if (! outputDevice->start())
            {
                close();
                lastError = TRANS("Couldn't start the output device!");
                return lastError;
            }
        }

        isOpen_ = true;
        return lastError;
    }

    void close() override
    {
        stop();
        signalThreadShouldExit();

        if (inputDevice != nullptr)   SetEvent (inputDevice->clientEvent);
        if (outputDevice != nullptr)  SetEvent (outputDevice->clientEvent);

        stopThread (5000);

        if (inputDevice != nullptr)   inputDevice->close();
        if (outputDevice != nullptr)  outputDevice->close();

        isOpen_ = false;
    }

    bool isOpen() override       { return isOpen_ && isThreadRunning(); }
    bool isPlaying() override    { return isStarted && isOpen_ && isThreadRunning(); }

    void start (AudioIODeviceCallback* call) override
    {
        if (isOpen_ && call != nullptr && ! isStarted)
        {
            if (! isThreadRunning())
            {
                // something's gone wrong and the thread's stopped..
                isOpen_ = false;
                return;
            }

            call->audioDeviceAboutToStart (this);

            const ScopedLock sl (startStopLock);
            callback = call;
            isStarted = true;
        }
    }

    void stop() override
    {
        if (isStarted)
        {
            auto* callbackLocal = callback;

            {
                const ScopedLock sl (startStopLock);
                isStarted = false;
            }

            if (callbackLocal != nullptr)
                callbackLocal->audioDeviceStopped();
        }
    }

    void setMMThreadPriority()
    {
        DynamicLibrary dll ("avrt.dll");
        JUCE_LOAD_WINAPI_FUNCTION (dll, AvSetMmThreadCharacteristicsW, avSetMmThreadCharacteristics, HANDLE, (LPCWSTR, LPDWORD))
        JUCE_LOAD_WINAPI_FUNCTION (dll, AvSetMmThreadPriority, avSetMmThreadPriority, HANDLE, (HANDLE, AVRT_PRIORITY))

        if (avSetMmThreadCharacteristics != nullptr && avSetMmThreadPriority != nullptr)
        {
            DWORD dummy = 0;

            if (auto h = avSetMmThreadCharacteristics (L"Pro Audio", &dummy))
                avSetMmThreadPriority (h, AVRT_PRIORITY_NORMAL);
        }
    }

    void run() override
    {
        setMMThreadPriority();

        auto bufferSize        = currentBufferSizeSamples;
        auto numInputBuffers   = getActiveInputChannels().countNumberOfSetBits();
        auto numOutputBuffers  = getActiveOutputChannels().countNumberOfSetBits();

        AudioBuffer<float> ins  (jmax (1, numInputBuffers),  bufferSize + 32);
        AudioBuffer<float> outs (jmax (1, numOutputBuffers), bufferSize + 32);
        auto inputBuffers  = ins.getArrayOfWritePointers();
        auto outputBuffers = outs.getArrayOfWritePointers();
        ins.clear();
        outs.clear();

        while (! threadShouldExit())
        {
            if ((outputDevice != nullptr && outputDevice->shouldShutdown)
                || (inputDevice != nullptr && inputDevice->shouldShutdown))
            {
                shouldShutdown = true;
                triggerAsyncUpdate();

                break;
            }

            auto inputDeviceActive = (inputDevice != nullptr && inputDevice->isActive);
            auto outputDeviceActive = (outputDevice != nullptr && outputDevice->isActive);

            if (! inputDeviceActive && ! outputDeviceActive)
                continue;

            if (inputDeviceActive)
            {
                if (outputDevice == nullptr)
                {
                    if (WaitForSingleObject (inputDevice->clientEvent, 1000) == WAIT_TIMEOUT)
                        break;

                    inputDevice->handleDeviceBuffer();

                    if (inputDevice->getNumSamplesInReservoir() < bufferSize)
                        continue;
                }
                else
                {
                    if (isExclusiveMode (deviceMode) && WaitForSingleObject (inputDevice->clientEvent, 0) == WAIT_OBJECT_0)
                        inputDevice->handleDeviceBuffer();
                }

                inputDevice->copyBuffersFromReservoir (inputBuffers, numInputBuffers, bufferSize);

                if (inputDevice->sampleRateHasChanged)
                {
                    deviceSampleRateChanged = true;
                    triggerAsyncUpdate();

                    break;
                }
            }

            {
                const ScopedTryLock sl (startStopLock);

                if (sl.isLocked() && isStarted)
                    callback->audioDeviceIOCallback (const_cast<const float**> (inputBuffers), numInputBuffers,
                                                     outputBuffers, numOutputBuffers, bufferSize);
                else
                    outs.clear();
            }

            if (outputDeviceActive)
            {
                // Note that this function is handed the input device so it can check for the event and make sure
                // the input reservoir is filled up correctly even when bufferSize > device actualBufferSize
                outputDevice->copyBuffers (const_cast<const float**> (outputBuffers), numOutputBuffers, bufferSize, inputDevice.get(), *this);

                if (outputDevice->sampleRateHasChanged)
                {
                    deviceSampleRateChanged = true;
                    triggerAsyncUpdate();

                    break;
                }
            }
        }
    }

    //==============================================================================
    String outputDeviceId, inputDeviceId;
    String lastError;

private:
    // Device stats...
    std::unique_ptr<WASAPIInputDevice> inputDevice;
    std::unique_ptr<WASAPIOutputDevice> outputDevice;
    WASAPIDeviceMode deviceMode;
    double defaultSampleRate = 0;
    int minBufferSize = 0, defaultBufferSize = 0;
    int lowLatencyMaxBufferSize = 0, lowLatencyBufferSizeMultiple = 0;
    int latencyIn = 0, latencyOut = 0;
    Array<double> sampleRates;
    Array<int> bufferSizes;

    // Active state...
    bool isOpen_ = false, isStarted = false;
    int currentBufferSizeSamples = 0;
    double currentSampleRate = 0;

    AudioIODeviceCallback* callback = {};
    CriticalSection startStopLock;

    std::atomic<bool> shouldShutdown { false }, deviceSampleRateChanged { false };

    BigInteger lastKnownInputChannels, lastKnownOutputChannels;

    //==============================================================================
    bool createDevices()
    {
        ComSmartPtr<IMMDeviceEnumerator> enumerator;

        if (! check (enumerator.CoCreateInstance (__uuidof (MMDeviceEnumerator))))
            return false;

        ComSmartPtr<IMMDeviceCollection> deviceCollection;

        if (! check (enumerator->EnumAudioEndpoints (eAll, DEVICE_STATE_ACTIVE, deviceCollection.resetAndGetPointerAddress())))
            return false;

        UINT32 numDevices = 0;

        if (! check (deviceCollection->GetCount (&numDevices)))
            return false;

        for (UINT32 i = 0; i < numDevices; ++i)
        {
            ComSmartPtr<IMMDevice> device;

            if (! check (deviceCollection->Item (i, device.resetAndGetPointerAddress())))
                continue;

            auto deviceId = getDeviceID (device);

            if (deviceId.isEmpty())
                continue;

            auto flow = getDataFlow (device);

            if (deviceId == inputDeviceId && flow == eCapture)
                inputDevice.reset (new WASAPIInputDevice (device, deviceMode));
            else if (deviceId == outputDeviceId && flow == eRender)
                outputDevice.reset (new WASAPIOutputDevice (device, deviceMode));
        }

        return (outputDeviceId.isEmpty() || (outputDevice != nullptr && outputDevice->isOk()))
             && (inputDeviceId.isEmpty() || (inputDevice != nullptr && inputDevice->isOk()));
    }

    //==============================================================================
    void handleAsyncUpdate() override
    {
        auto closeDevices = [this]
        {
            close();

            outputDevice = nullptr;
            inputDevice = nullptr;
        };

        if (shouldShutdown)
        {
            closeDevices();
        }
        else if (deviceSampleRateChanged)
        {
            auto sampleRateChangedByInput = (inputDevice != nullptr && inputDevice->sampleRateHasChanged);

            closeDevices();
            initialise();

            auto changedSampleRate = [this, sampleRateChangedByInput]()
            {
                if (inputDevice != nullptr && sampleRateChangedByInput)
                    return inputDevice->defaultSampleRate;

                if (outputDevice != nullptr && ! sampleRateChangedByInput)
                    return outputDevice->defaultSampleRate;

                return 0.0;
            }();

            open (lastKnownInputChannels, lastKnownOutputChannels,
                  changedSampleRate, currentBufferSizeSamples);

            start (callback);
        }
    }

    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (WASAPIAudioIODevice)
};


//==============================================================================
class WASAPIAudioIODeviceType  : public AudioIODeviceType,
                                 private DeviceChangeDetector
{
public:
    WASAPIAudioIODeviceType (WASAPIDeviceMode mode)
        : AudioIODeviceType (getDeviceTypename (mode)),
          DeviceChangeDetector (L"Windows Audio"),
          deviceMode (mode)
    {
    }

    ~WASAPIAudioIODeviceType() override
    {
        if (notifyClient != nullptr)
            enumerator->UnregisterEndpointNotificationCallback (notifyClient);
    }

    //==============================================================================
    void scanForDevices() override
    {
        hasScanned = true;

        outputDeviceNames.clear();
        inputDeviceNames.clear();
        outputDeviceIds.clear();
        inputDeviceIds.clear();

        scan (outputDeviceNames, inputDeviceNames,
              outputDeviceIds, inputDeviceIds);
    }

    StringArray getDeviceNames (bool wantInputNames) const override
    {
        jassert (hasScanned); // need to call scanForDevices() before doing this

        return wantInputNames ? inputDeviceNames
                              : outputDeviceNames;
    }

    int getDefaultDeviceIndex (bool /*forInput*/) const override
    {
        jassert (hasScanned); // need to call scanForDevices() before doing this
        return 0;
    }

    int getIndexOfDevice (AudioIODevice* device, bool asInput) const override
    {
        jassert (hasScanned); // need to call scanForDevices() before doing this

        if (auto d = dynamic_cast<WASAPIAudioIODevice*> (device))
            return asInput ? inputDeviceIds.indexOf (d->inputDeviceId)
                           : outputDeviceIds.indexOf (d->outputDeviceId);

        return -1;
    }

    bool hasSeparateInputsAndOutputs() const override    { return true; }

    AudioIODevice* createDevice (const String& outputDeviceName,
                                 const String& inputDeviceName) override
    {
        jassert (hasScanned); // need to call scanForDevices() before doing this

        std::unique_ptr<WASAPIAudioIODevice> device;

        auto outputIndex = outputDeviceNames.indexOf (outputDeviceName);
        auto inputIndex = inputDeviceNames.indexOf (inputDeviceName);

        if (outputIndex >= 0 || inputIndex >= 0)
        {
            device.reset (new WASAPIAudioIODevice (outputDeviceName.isNotEmpty() ? outputDeviceName
                                                                                 : inputDeviceName,
                                                   getTypeName(),
                                                   outputDeviceIds [outputIndex],
                                                   inputDeviceIds [inputIndex],
                                                   deviceMode));

            if (! device->initialise())
                device = nullptr;
        }

        return device.release();
    }

    //==============================================================================
    StringArray outputDeviceNames, outputDeviceIds;
    StringArray inputDeviceNames, inputDeviceIds;

private:
    WASAPIDeviceMode deviceMode;
    bool hasScanned = false;
    ComSmartPtr<IMMDeviceEnumerator> enumerator;

    //==============================================================================
    class ChangeNotificationClient : public ComBaseClassHelper<IMMNotificationClient>
    {
    public:
        ChangeNotificationClient (WASAPIAudioIODeviceType* d)
            : ComBaseClassHelper (0), device (d) {}

        JUCE_COMRESULT OnDeviceAdded (LPCWSTR)                             { return notify(); }
        JUCE_COMRESULT OnDeviceRemoved (LPCWSTR)                           { return notify(); }
        JUCE_COMRESULT OnDeviceStateChanged(LPCWSTR, DWORD)                { return notify(); }
        JUCE_COMRESULT OnDefaultDeviceChanged (EDataFlow, ERole, LPCWSTR)  { return notify(); }
        JUCE_COMRESULT OnPropertyValueChanged (LPCWSTR, const PROPERTYKEY) { return notify(); }

    private:
        WeakReference<WASAPIAudioIODeviceType> device;

        HRESULT notify()
        {
            if (device != nullptr)
                device->triggerAsyncDeviceChangeCallback();

            return S_OK;
        }

        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ChangeNotificationClient)
    };

    ComSmartPtr<ChangeNotificationClient> notifyClient;

    //==============================================================================
    static String getDefaultEndpoint (IMMDeviceEnumerator* enumerator, bool forCapture)
    {
        String s;
        IMMDevice* dev = nullptr;

        if (check (enumerator->GetDefaultAudioEndpoint (forCapture ? eCapture : eRender,
                                                        eMultimedia, &dev)))
        {
            WCHAR* deviceId = nullptr;

            if (check (dev->GetId (&deviceId)))
            {
                s = deviceId;
                CoTaskMemFree (deviceId);
            }

            dev->Release();
        }

        return s;
    }

    //==============================================================================
    void scan (StringArray& outDeviceNames,
               StringArray& inDeviceNames,
               StringArray& outDeviceIds,
               StringArray& inDeviceIds)
    {
        if (enumerator == nullptr)
        {
            if (! check (enumerator.CoCreateInstance (__uuidof (MMDeviceEnumerator))))
                return;

            notifyClient = new ChangeNotificationClient (this);
            enumerator->RegisterEndpointNotificationCallback (notifyClient);
        }

        auto defaultRenderer = getDefaultEndpoint (enumerator, false);
        auto defaultCapture  = getDefaultEndpoint (enumerator, true);

        ComSmartPtr<IMMDeviceCollection> deviceCollection;
        UINT32 numDevices = 0;

        if (! (check (enumerator->EnumAudioEndpoints (eAll, DEVICE_STATE_ACTIVE, deviceCollection.resetAndGetPointerAddress()))
                && check (deviceCollection->GetCount (&numDevices))))
            return;

        for (UINT32 i = 0; i < numDevices; ++i)
        {
            ComSmartPtr<IMMDevice> device;

            if (! check (deviceCollection->Item (i, device.resetAndGetPointerAddress())))
                continue;

            DWORD state = 0;

            if (! (check (device->GetState (&state)) && state == DEVICE_STATE_ACTIVE))
                continue;

            auto deviceId = getDeviceID (device);
            String name;

            {
                ComSmartPtr<IPropertyStore> properties;

                if (! check (device->OpenPropertyStore (STGM_READ, properties.resetAndGetPointerAddress())))
                    continue;

                PROPVARIANT value;
                zerostruct (value);

                const PROPERTYKEY PKEY_Device_FriendlyName
                    = { { 0xa45c254e, 0xdf1c, 0x4efd, { 0x80, 0x20, 0x67, 0xd1, 0x46, 0xa8, 0x50, 0xe0 } }, 14 };

                if (check (properties->GetValue (PKEY_Device_FriendlyName, &value)))
                    name = value.pwszVal;

                PropVariantClear (&value);
            }

            auto flow = getDataFlow (device);

            if (flow == eRender)
            {
                const int index = (deviceId == defaultRenderer) ? 0 : -1;
                outDeviceIds.insert (index, deviceId);
                outDeviceNames.insert (index, name);
            }
            else if (flow == eCapture)
            {
                const int index = (deviceId == defaultCapture) ? 0 : -1;
                inDeviceIds.insert (index, deviceId);
                inDeviceNames.insert (index, name);
            }
        }

        inDeviceNames.appendNumbersToDuplicates (false, false);
        outDeviceNames.appendNumbersToDuplicates (false, false);
    }

    //==============================================================================
    void systemDeviceChanged() override
    {
        StringArray newOutNames, newInNames, newOutIds, newInIds;
        scan (newOutNames, newInNames, newOutIds, newInIds);

        if (newOutNames != outputDeviceNames
             || newInNames != inputDeviceNames
             || newOutIds != outputDeviceIds
             || newInIds != inputDeviceIds)
        {
            hasScanned = true;
            outputDeviceNames = newOutNames;
            inputDeviceNames = newInNames;
            outputDeviceIds = newOutIds;
            inputDeviceIds = newInIds;
        }

        callDeviceChangeListeners();
    }

    //==============================================================================
    static String getDeviceTypename (WASAPIDeviceMode mode)
    {
        if (mode == WASAPIDeviceMode::shared)            return "Windows Audio";
        if (mode == WASAPIDeviceMode::sharedLowLatency)  return "Windows Audio (Low Latency Mode)";
        if (mode == WASAPIDeviceMode::exclusive)         return "Windows Audio (Exclusive Mode)";

        jassertfalse;
        return {};
    }

    //==============================================================================
    JUCE_DECLARE_WEAK_REFERENCEABLE (WASAPIAudioIODeviceType)
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (WASAPIAudioIODeviceType)
};

//==============================================================================
struct MMDeviceMasterVolume
{
    MMDeviceMasterVolume()
    {
        ComSmartPtr<IMMDeviceEnumerator> enumerator;

        if (check (enumerator.CoCreateInstance (__uuidof (MMDeviceEnumerator))))
        {
            ComSmartPtr<IMMDevice> device;

            if (check (enumerator->GetDefaultAudioEndpoint (eRender, eConsole, device.resetAndGetPointerAddress())))
                check (device->Activate (__uuidof (IAudioEndpointVolume), CLSCTX_INPROC_SERVER, nullptr,
                                         (void**) endpointVolume.resetAndGetPointerAddress()));
        }
    }

    float getGain() const
    {
        float vol = 0.0f;

        if (endpointVolume != nullptr)
            check (endpointVolume->GetMasterVolumeLevelScalar (&vol));

        return vol;
    }

    bool setGain (float newGain) const
    {
        return endpointVolume != nullptr
                && check (endpointVolume->SetMasterVolumeLevelScalar (jlimit (0.0f, 1.0f, newGain), nullptr));
    }

    bool isMuted() const
    {
        BOOL mute = 0;
        return endpointVolume != nullptr
                 && check (endpointVolume->GetMute (&mute)) && mute != 0;
    }

    bool setMuted (bool shouldMute) const
    {
        return endpointVolume != nullptr
                && check (endpointVolume->SetMute (shouldMute, nullptr));
    }

    ComSmartPtr<IAudioEndpointVolume> endpointVolume;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (MMDeviceMasterVolume)
};

}

//==============================================================================
#define JUCE_SYSTEMAUDIOVOL_IMPLEMENTED 1
float JUCE_CALLTYPE SystemAudioVolume::getGain()              { return WasapiClasses::MMDeviceMasterVolume().getGain(); }
bool  JUCE_CALLTYPE SystemAudioVolume::setGain (float gain)   { return WasapiClasses::MMDeviceMasterVolume().setGain (gain); }
bool  JUCE_CALLTYPE SystemAudioVolume::isMuted()              { return WasapiClasses::MMDeviceMasterVolume().isMuted(); }
bool  JUCE_CALLTYPE SystemAudioVolume::setMuted (bool mute)   { return WasapiClasses::MMDeviceMasterVolume().setMuted (mute); }

JUCE_END_IGNORE_WARNINGS_GCC_LIKE

} // namespace juce