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