Background Task Dialog

// BackgroundTaskDialog.cpp : implementation file
//

#include "stdafx.h"
#include "BackgroundTaskDialog.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////

static UINT RunBackgroundTaskProc(LPVOID pParam);

/////////////////////////////////////////////////////////////////////////////
// CBackgroundTaskDialog dialog

CBackgroundTaskDialog::CBackgroundTaskDialog(UINT nIDD, CWnd* pParent /*=NULL*/)
	: CDialog(nIDD, pParent)
{
	//{{AFX_DATA_INIT(CBackgroundTaskDialog)
		// NOTE: the ClassWizard will add member initialization here
	//}}AFX_DATA_INIT
	hKillBackgroundThreadEvent = hDoneBackgroundThreadEvent = NULL;
	lpBackgroundThread = NULL;
	return;
}

CBackgroundTaskDialog::~CBackgroundTaskDialog()
{
	StopBackgroundTask();
	return;
}

void CBackgroundTaskDialog::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CBackgroundTaskDialog)
		// NOTE: the ClassWizard will add DDX and DDV calls here
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CBackgroundTaskDialog, CDialog)
	//{{AFX_MSG_MAP(CBackgroundTaskDialog)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////

int CBackgroundTaskDialog::StartBackgroundTask()
{
	if (lpBackgroundThread != NULL) {
		if (IsBackgroundTaskRunning() != FALSE)
			return -1;
		//If the thread has ended call StopBackgroundTask in order
		//to cleanup some stuff
		StopBackgroundTask();
	}
	//create kill thread event
	hKillBackgroundThreadEvent = ::CreateEvent(NULL, TRUE, FALSE, NULL);
	if (hKillBackgroundThreadEvent == NULL)
		return -2;
	//create work-done thread event
	hDoneBackgroundThreadEvent = ::CreateEvent(NULL, TRUE, FALSE, NULL);
	if (hDoneBackgroundThreadEvent == NULL) {
		::CloseHandle(hKillBackgroundThreadEvent);
		hKillBackgroundThreadEvent = NULL;
		return -3;
	}
	//create thread itself
	lpBackgroundThread = AfxBeginThread(RunBackgroundTaskProc, this, THREAD_PRIORITY_NORMAL, 0, CREATE_SUSPENDED);
	if (lpBackgroundThread == NULL) {
		::CloseHandle(hDoneBackgroundThreadEvent);
		hDoneBackgroundThreadEvent = NULL;
		::CloseHandle(hKillBackgroundThreadEvent);
		hKillBackgroundThreadEvent = NULL;
		return -4;
	}
	lpBackgroundThread->m_bAutoDelete = FALSE;
	//resume thread
	::ResumeThread(lpBackgroundThread->m_hThread);
	return 1;
}

int CBackgroundTaskDialog::StopBackgroundTask(int nTimeOut)
{
	MSG msg;
	DWORD dwExitCode;
	int tim, nTimeCounter;

	if (lpBackgroundThread == NULL)
		return -1;
	//I dont know why sometimes finished threads don't get signalled
	if ((::WaitForSingleObject(hDoneBackgroundThreadEvent, 0) != WAIT_OBJECT_0) &&
		  (::GetExitCodeThread(lpBackgroundThread->m_hThread, &dwExitCode) && dwExitCode==STILL_ACTIVE)) {
	  //thread is still active...
		//send kill event
		::SetEvent(hKillBackgroundThreadEvent);
		//wait for thread completion
		for (nTimeCounter=nTimeOut;;) {
			if (nTimeOut > 0) {
				if ((tim = nTimeCounter) > 100)
					tim = 100;
			}
			else
				tim = 0;
			if (::WaitForSingleObject(hDoneBackgroundThreadEvent, tim) == WAIT_OBJECT_0)
				break;
			if (::PeekMessage(&msg, NULL, NULL, NULL, PM_NOREMOVE) != 0) {
				if (AfxGetThread()->PumpMessage() == FALSE) {
					::TerminateThread(lpBackgroundThread->m_hThread, 0);
					::PostQuitMessage(msg.wParam);
					break;
				}
			}
			if (::GetExitCodeThread(lpBackgroundThread->m_hThread, &dwExitCode) && dwExitCode!=STILL_ACTIVE)
				break;
			if (nTimeOut > 0) {
				if ((nTimeCounter -= tim) == 0) {
					::TerminateThread(lpBackgroundThread->m_hThread, 0);
					break;
				}
			}
		}
	}
	//cleanup
	if (lpBackgroundThread != NULL) {
		delete lpBackgroundThread;
		lpBackgroundThread = NULL;
	}
	if (hDoneBackgroundThreadEvent != NULL) {
		::CloseHandle(hDoneBackgroundThreadEvent);
		hDoneBackgroundThreadEvent = NULL;
	}
	if (hKillBackgroundThreadEvent != NULL) {
		::CloseHandle(hKillBackgroundThreadEvent);
		hKillBackgroundThreadEvent = NULL;
	}
	return 1;
}

BOOL CBackgroundTaskDialog::CheckForBackgroundTaskAbort()
{
	if (lpBackgroundThread == NULL)
		return TRUE;
	if (::WaitForSingleObject(hKillBackgroundThreadEvent, 0) == WAIT_OBJECT_0)
		return TRUE;
	return FALSE;
}

BOOL CBackgroundTaskDialog::IsBackgroundTaskRunning()
{
	DWORD dwExitCode;

	if (lpBackgroundThread == NULL)
		return FALSE;
	if (::WaitForSingleObject(hDoneBackgroundThreadEvent, 0) == WAIT_OBJECT_0)
		return FALSE;
	if (::GetExitCodeThread(lpBackgroundThread->m_hThread, &dwExitCode) && dwExitCode!=STILL_ACTIVE)
		return FALSE;
	return TRUE;
}

/////////////////////////////////////////////////////////////////////////////
// OVERRIDABLES

void CBackgroundTaskDialog::RunBackgroundTask()
{
	return;
}

/////////////////////////////////////////////////////////////////////////////
// INTERNAL FUNCTIONS

static UINT RunBackgroundTaskProc(LPVOID pParam)
{
	CBackgroundTaskDialog *bt_dlg;

	bt_dlg = (CBackgroundTaskDialog*)pParam;
	bt_dlg->RunBackgroundTask();
	::SetEvent(bt_dlg->hDoneBackgroundThreadEvent);
	return 1;
}