Source code of Windows XP (NT5)
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#if !defined(_FUSION_INC_ASYNCHELP_H_INCLUDED_)
#define _FUSION_INC_ASYNCHELP_H_INCLUDED_
#pragma once
class CAsyncContext : public OVERLAPPED
{
public:
CAsyncContext() { }
virtual ~CAsyncContext() { }
// Public handler for async operations which are finished via an I/O completion port
static VOID OnQueuedCompletion(HANDLE hCompletionPort, DWORD cbTransferred, ULONG_PTR ulCompletionKey, LPOVERLAPPED lpo)
{
CAsyncContext *pThis = reinterpret_cast<CAsyncContext *>(ulCompletionKey);
INVOCATION_CONTEXT ic;
ic.m_it = CAsyncContext::INVOCATION_CONTEXT::eCompletionPort;
ic.m_dwErrorCode = ERROR_SUCCESS;
ic.m_hCompletionPort = hCompletionPort;
ic.m_lpo = lpo;
ic.m_cbTransferred = cbTransferred;
pThis->OnCompletion(ic);
}
// Public handler for async operations which are signalled via an APC.
static VOID CALLBACK OnUserAPC(DWORD_PTR dwParam)
{
CAsyncContext *pThis = reinterpret_cast<CAsyncContext *>(dwParam);
INVOCATION_CONTEXT ic;
ic.m_it = CAsyncContext::INVOCATION_CONTEXT::eUserAPC;
ic.m_dwErrorCode = ERROR_SUCCESS;
pThis->OnCompletion(ic);
}
// Public handler for async operations which are signalled via a thread message
static VOID OnThreadMessage(UINT uMsg, WPARAM wParam, LPARAM lParam)
{
CAsyncContext *pThis = reinterpret_cast<CAsyncContext *>(wParam);
INVOCATION_CONTEXT ic;
ic.m_it = CAsyncContext::INVOCATION_CONTEXT::eThreadMessage;
ic.m_dwErrorCode = ERROR_SUCCESS;
ic.m_uMsg = uMsg;
ic.m_lParam = lParam;
pThis->OnCompletion(ic);
}
// Public handler for async operations which are signalled via a window message
static VOID OnWindowMessage(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
CAsyncContext *pThis = reinterpret_cast<CAsyncContext *>(wParam);
INVOCATION_CONTEXT ic;
ic.m_it = CAsyncContext::INVOCATION_CONTEXT::eWindowMessage;
ic.m_dwErrorCode = ERROR_SUCCESS;
ic.m_hwnd = hwnd;
ic.m_uMsg = uMsg;
ic.m_lParam = lParam;
pThis->OnCompletion(ic);
}
// Public handler for async operations which are signalled via an overlapped completion routine
// (e.g. ReadFileEx(), WriteFileEx()).
static VOID CALLBACK OnOverlappedCompletion(DWORD dwErrorCode, DWORD cbTransferred, LPOVERLAPPED lpo)
{
CAsyncContext *pThis = static_cast<CAsyncContext *>(lpo);
INVOCATION_CONTEXT ic;
ic.m_it = CAsyncContext::INVOCATION_CONTEXT::eOverlappedCompletionRoutine;
ic.m_lpo = lpo;
ic.m_dwErrorCode = dwErrorCode;
ic.m_cbTransferred = cbTransferred;
pThis->OnCompletion(ic);
}
// Call this member function when an asynch I/O completes immediately
VOID OnImmediateCompletion(DWORD dwErrorCode, DWORD cbTransferred)
{
INVOCATION_CONTEXT ic;
ic.m_it = CAsyncContext::INVOCATION_CONTEXT::eDirectCall;
ic.m_lpo = this;
ic.m_dwErrorCode = dwErrorCode;
ic.m_cbTransferred = cbTransferred;
this->OnCompletion(ic);
}
protected:
struct INVOCATION_CONTEXT
{
enum InvocationType
{
eCompletionPort,
eUserAPC,
eThreadMessage,
eWindowMessage,
eDirectCall,
eOverlappedCompletionRoutine,
} m_it;
DWORD m_dwErrorCode; // Win32 error code - valid for all invocation types
HANDLE m_hCompletionPort; // valid for: eCompletionPort
LPOVERLAPPED m_lpo; // valid for: eCompletionPort, eOverlappedCompletionRoutine, eDirectCall
DWORD m_cbTransferred; // valid for: eCompletionPort, eOverlappedCompletionRoutine, eDirectCall
LPARAM m_lParam; // valid for: eThreadMessage, eWindowMessage
HWND m_hwnd; // valid for: eWindowMessage
UINT m_uMsg; // valid for: eThreadMessage, eWindowMessage
};
// Derived classes override OnCompletion to do what's necessary.
virtual VOID OnCompletion(const INVOCATION_CONTEXT &ric) = 0;
};
#endif