FileInfoProvider.cpp

//Регистрация в Plugin::Initialize()
if (FAILED(core->RegisterExtension(IID_IAIMPServiceFileInfo, new FileInfoProvider)))
	return Fail();
		
class FileInfoProvider final
		: public IUnknownII<IAIMPExtensionFileInfoProvider>
{
public:
	FileInfoProvider() = default;

	HRESULT WINAPI QueryInterface(
		const IID& riid, LPVOID* ppvObj) override
	{
		if (!ppvObj) return E_POINTER;

		if (riid == IID_IAIMPExtensionFileInfoProvider)
		{
			*ppvObj = this;
			AddRef();
			return S_OK;
		}

		return E_NOINTERFACE;
	}

	HRESULT WINAPI GetFileInfo(
		IAIMPString* fileUri, IAIMPFileInfo* info) override
	{
		/*Code*/
		return S_OK;
	}
};