Mencari Secara Asinkron di C++

Kode berikut dapat digunakan sebagai dasar untuk aplikasi C++ yang mencari perangkat secara asinkron. Kode ini mengimplementasikan antarmuka IUPnPDeviceFinderCallback dengan membuat kelas yang mewarisinya.

Untuk mengimplementasikan IUPnPDeviceFinderCallback dan IUPnPDeviceFinderAddCallbackWithInterface, kelas harus mewarisi dari kedua antarmuka. Implementasi IUPnPDeviceFinderAddCallbackWithInterface bersifat opsional, tetapi jika Anda memilih untuk menerapkannya, Anda juga harus menerapkan IUPnPDeviceFinderCallback.

#include <windows.h>
#include <upnp.h>
#include <stdio.h>

#pragma comment(lib, "ole32.lib")
#pragma comment(lib, "oleaut32.lib")
#pragma comment(lib, "user32.lib")

class CUPnPDeviceFinderCallback : public IUPnPDeviceFinderCallback
{
public:
    CUPnPDeviceFinderCallback()
    {
        m_lRefCount = 0;
    };
    
    STDMETHODIMP QueryInterface(REFIID iid, LPVOID* ppvObject)
    {
        HRESULT hr = S_OK;
        
        if(NULL == ppvObject)
        {
            hr = E_POINTER;
        }
        else
        {
            *ppvObject = NULL;
        }
        
        if(SUCCEEDED(hr))
        {
            if(IsEqualIID(iid, IID_IUnknown) || IsEqualIID(iid, IID_IUPnPDeviceFinderCallback))
            {
                *ppvObject = static_cast<IUPnPDeviceFinderCallback*>(this);
                AddRef();
            }
            else
            {
                hr = E_NOINTERFACE;
            }
        }
        
        return hr;
    };
    
    STDMETHODIMP_(ULONG) AddRef()
    {
        return ::InterlockedIncrement(&m_lRefCount);
    };
    
    STDMETHODIMP_(ULONG) Release()
    {
        LONG lRefCount = ::InterlockedDecrement(&m_lRefCount);
        if(0 == lRefCount)
        {
            delete this;
        }
        
        return lRefCount;
    };
    
    STDMETHODIMP DeviceAdded(LONG lFindData, IUPnPDevice* pDevice)
    {
        HRESULT hr = S_OK;

        //You should save pDevice so that it is accessible outside the scope of this method.

        BSTR UniqueDeviceName;
        hr = pDevice->get_UniqueDeviceName(&UniqueDeviceName);
        if (SUCCEEDED(hr))
        {
            BSTR FriendlyName;
            hr = pDevice->get_FriendlyName(&FriendlyName);
            if (SUCCEEDED(hr))
            {
                printf("Device Added: udn: %S, name: %S\n", FriendlyName, UniqueDeviceName);
                ::SysFreeString(FriendlyName);
            }
            ::SysFreeString(UniqueDeviceName);
        }
        return hr;
        
    };
    
    STDMETHODIMP DeviceRemoved(LONG lFindData, BSTR bstrUDN)
    {
        printf("Device Removed: udn: %S", bstrUDN);
        return S_OK;
    };
    
    STDMETHODIMP SearchComplete(LONG lFindData)
    {
        return S_OK;
    };
    
    
    
private:
    LONG m_lRefCount;
    
};

HRESULT FindUPnPDevice(BSTR TypeURI)
{
    HRESULT hr = S_OK;
    
    IUPnPDeviceFinderCallback* pUPnPDeviceFinderCallback = new CUPnPDeviceFinderCallback();
    if(NULL != pUPnPDeviceFinderCallback)
    {
        pUPnPDeviceFinderCallback->AddRef();
        IUPnPDeviceFinder* pUPnPDeviceFinder;
        hr = CoCreateInstance(CLSID_UPnPDeviceFinder, NULL, CLSCTX_INPROC_SERVER, 
            IID_IUPnPDeviceFinder, reinterpret_cast<void**>(&pUPnPDeviceFinder));
        if(SUCCEEDED(hr))
        {
            LONG lFindData;
            hr = pUPnPDeviceFinder->CreateAsyncFind(TypeURI, 0, pUPnPDeviceFinderCallback, &lFindData);
            if(SUCCEEDED(hr))
            {
                hr = pUPnPDeviceFinder->StartAsyncFind(lFindData);
                if(SUCCEEDED(hr))
                {
                    // STA threads must pump messages
                    MSG Message;
                    BOOL bGetMessage;
                    while(bGetMessage = GetMessage(&Message, NULL, 0, 0) && -1 != bGetMessage)
                    {
                        DispatchMessage(&Message);      
                    }
                }
                pUPnPDeviceFinder->CancelAsyncFind(lFindData);
            }
            pUPnPDeviceFinder->Release();
        }
        pUPnPDeviceFinderCallback->Release();
    }
    else
    {
        hr = E_OUTOFMEMORY;
    }
   
    return hr;
}