1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
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;
};