WindowsMMNotificationClient.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "HAL/Platform.h"
 
#include <atomic>
#include "AudioMixer.h" 
#include "Misc/ScopeRWLock.h"
 
#include "Windows/AllowWindowsPlatformTypes.h"
#include "Windows/AllowWindowsPlatformAtomics.h"
 
#include "Microsoft/COMPointer.h"
 
THIRD_PARTY_INCLUDES_START
#include <mmdeviceapi.h>            // IMMNotificationClient
#include <audiopolicy.h>            // IAudioSessionEvents
THIRD_PARTY_INCLUDES_END
 
#include "Windows/HideWindowsPlatformAtomics.h"
#include "Windows/HideWindowsPlatformTypes.h"
 
namespace Audio
{
    class IAudioMixerDeviceChangedListener;
 
    class FWindowsMMNotificationClient final : public IMMNotificationClient
#if PLATFORM_WINDOWS
        , public IAudioSessionEvents
#endif //PLATFORM_WINDOWS
    {
    public:
        WINDOWSMMDEVICEENUMERATION_API FWindowsMMNotificationClient();
        ~FWindowsMMNotificationClient();
 
        // TODO: Ideally we'd use the cache instead of ask for this.
        WINDOWSMMDEVICEENUMERATION_API bool IsRenderDevice(const FString& InDeviceId) const;
 
        WINDOWSMMDEVICEENUMERATION_API FString GetFriendlyName(const FString InDeviceID);
        WINDOWSMMDEVICEENUMERATION_API FString GetFriendlyName(const TComPtr<IMMDevice>& InDevice);
 
        WINDOWSMMDEVICEENUMERATION_API TComPtr<IMMDevice> GetDevice(const FString InDeviceID) const;
        WINDOWSMMDEVICEENUMERATION_API uint32 ReleaseClient();
 
        WINDOWSMMDEVICEENUMERATION_API void RegisterDeviceChangedListener(Audio::IAudioMixerDeviceChangedListener* DeviceChangedListener);
        WINDOWSMMDEVICEENUMERATION_API void UnRegisterDeviceDeviceChangedListener(Audio::IAudioMixerDeviceChangedListener* DeviceChangedListener);
 
        // Begin IUnknown overrides
        HRESULT STDMETHODCALLTYPE QueryInterface(const IID& IId, void** UnknownPtrPtr) override;
        ULONG STDMETHODCALLTYPE AddRef() override;
        ULONG STDMETHODCALLTYPE Release() override;
        // End IUnknown overrides
        
        // Begin IMMNotificationClient overrides
        HRESULT STDMETHODCALLTYPE OnDefaultDeviceChanged(EDataFlow InFlow, ERole InRole, LPCWSTR pwstrDeviceId) override;
        HRESULT STDMETHODCALLTYPE OnDeviceAdded(LPCWSTR pwstrDeviceId) override;;
        HRESULT STDMETHODCALLTYPE OnDeviceRemoved(LPCWSTR pwstrDeviceId) override;
        HRESULT STDMETHODCALLTYPE OnDeviceStateChanged(LPCWSTR pwstrDeviceId, DWORD dwNewState) override;
        HRESULT STDMETHODCALLTYPE OnPropertyValueChanged(LPCWSTR pwstrDeviceId, const PROPERTYKEY key);
        // End IMMNotificationClient overrides
 
#if PLATFORM_WINDOWS
        WINDOWSMMDEVICEENUMERATION_API bool RegisterForSessionNotifications(const TComPtr<IMMDevice>& InDevice);
        WINDOWSMMDEVICEENUMERATION_API bool RegisterForSessionNotifications(const FString& InDeviceId);
        WINDOWSMMDEVICEENUMERATION_API void UnregisterForSessionNotifications();
 
        // Begin IAudioSessionEvents overrides
        HRESULT STDMETHODCALLTYPE OnDisplayNameChanged(
            LPCWSTR NewDisplayName,
            LPCGUID EventContext) override;
 
        HRESULT STDMETHODCALLTYPE OnIconPathChanged(
            LPCWSTR NewIconPath,
            LPCGUID EventContext) override;
 
        HRESULT STDMETHODCALLTYPE OnSimpleVolumeChanged(
            float NewVolume,
            BOOL NewMute,
            LPCGUID EventContext) override;
 
        HRESULT STDMETHODCALLTYPE OnChannelVolumeChanged(
            DWORD ChannelCount,
            float NewChannelVolumeArray[],
            DWORD ChangedChannel,
            LPCGUID EventContext) override;
 
        HRESULT STDMETHODCALLTYPE OnGroupingParamChanged(
            LPCGUID NewGroupingParam,
            LPCGUID EventContext) override;
 
        HRESULT STDMETHODCALLTYPE OnStateChanged(
            AudioSessionState NewState) override;
 
        HRESULT STDMETHODCALLTYPE OnSessionDisconnected(
            AudioSessionDisconnectReason InDisconnectReason);
        // End IAudioSessionEvents overrides
 
    private:
        FCriticalSection SessionRegistrationCS;
        TComPtr<IAudioSessionManager> SessionManager;
        TComPtr<IAudioSessionControl> SessionControls;
        TComPtr<IMMDevice> DeviceListeningToSessionEvents;
 
        bool bComInitialized = false;
        std::atomic<bool> bHasDisconnectSessionHappened = false;
 
#endif //PLATFORM_WINDOWS
        
    private:
        LONG Ref = 1; // Start with self-reference
        TSet<Audio::IAudioMixerDeviceChangedListener*> Listeners;
        FRWLock ListenersSetRwLock;
        TComPtr<IMMDeviceEnumerator> DeviceEnumerator = nullptr;
    };
}// namespace Audio