init - 初始化项目

samples/winrt/ImageManipulations/MediaExtensions/Common/AsyncCB.h

@@ -0,0 +1,81 @@
+#pragma once
+
+//////////////////////////////////////////////////////////////////////////
+//  AsyncCallback [template]
+//
+//  Description:
+//  Helper class that routes IMFAsyncCallback::Invoke calls to a class
+//  method on the parent class.
+//
+//  Usage:
+//  Add this class as a member variable. In the parent class constructor,
+//  initialize the AsyncCallback class like this:
+//  	m_cb(this, &CYourClass::OnInvoke)
+//  where
+//      m_cb       = AsyncCallback object
+//      CYourClass = parent class
+//      OnInvoke   = Method in the parent class to receive Invoke calls.
+//
+//  The parent's OnInvoke method (you can name it anything you like) must
+//  have a signature that matches the InvokeFn typedef below.
+//////////////////////////////////////////////////////////////////////////
+
+// T: Type of the parent object
+template<class T>
+class AsyncCallback : public IMFAsyncCallback
+{
+public:
+    typedef HRESULT (T::*InvokeFn)(IMFAsyncResult *pAsyncResult);
+
+    AsyncCallback(T *pParent, InvokeFn fn) : m_pParent(pParent), m_pInvokeFn(fn)
+    {
+    }
+
+    // IUnknown
+    STDMETHODIMP_(ULONG) AddRef() {
+        // Delegate to parent class.
+        return m_pParent->AddRef();
+    }
+    STDMETHODIMP_(ULONG) Release() {
+        // Delegate to parent class.
+        return m_pParent->Release();
+    }
+    STDMETHODIMP QueryInterface(REFIID iid, void** ppv)
+    {
+        if (!ppv)
+        {
+            return E_POINTER;
+        }
+        if (iid == __uuidof(IUnknown))
+        {
+            *ppv = static_cast<IUnknown*>(static_cast<IMFAsyncCallback*>(this));
+        }
+        else if (iid == __uuidof(IMFAsyncCallback))
+        {
+            *ppv = static_cast<IMFAsyncCallback*>(this);
+        }
+        else
+        {
+            *ppv = NULL;
+            return E_NOINTERFACE;
+        }
+        AddRef();
+        return S_OK;
+    }
+
+
+    // IMFAsyncCallback methods
+    STDMETHODIMP GetParameters(DWORD*, DWORD*)
+    {
+        // Implementation of this method is optional.
+        return E_NOTIMPL;
+    }
+
+    STDMETHODIMP Invoke(IMFAsyncResult* pAsyncResult)
+    {
+        return (m_pParent->*m_pInvokeFn)(pAsyncResult);
+    }
+
+    T *m_pParent;
+    InvokeFn m_pInvokeFn;
+};