MFC 匿名管道 重定向的问题

[cr945211]

之前发过很多帖子问过在VS上做界面，通过匿名管道调用外部编译器的问题，现在自己的项目基本实现了通过匿名管道、重定向cmd窗口的输入输出，从而实现了调用外部编译器MiGW。关键代码如下

#define BUFSIZE 4096*100

BOOL CShellView::CreateShellRedirect()
{
	SECURITY_ATTRIBUTES saAttr;
	BOOL fSuccess;

	// Set the bInheritHandle flag so pipe handles are inherited.
	saAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
	saAttr.bInheritHandle = TRUE;
	saAttr.lpSecurityDescriptor = NULL;

	// The steps for redirecting child process's STDOUT: 
	//     1. Save current STDOUT, to be restored later. 
	//     2. Create anonymous pipe to be STDOUT for child process. 
	//     3. Set STDOUT of the parent process to be write handle to 
	//        the pipe, so it is inherited by the child process. 
	//     4. Create a noninheritable duplicate of the read handle and
	//        close the inheritable read handle.  
	
	// Save the handle to the current STDOUT.  
	hSaveStdout = GetStdHandle(STD_OUTPUT_HANDLE);  
	
	// Create a pipe for the child process's STDOUT.  
	if( !CreatePipe( &hChildStdoutRd, &hChildStdoutWr, &saAttr, 0) )
	{
		TRACE0( _T("Stdout pipe creation failed\n") );
		return FALSE;
	}

	// Set a write handle to the pipe to be STDOUT.  
	if( !SetStdHandle(STD_OUTPUT_HANDLE, hChildStdoutWr) )
	{
		TRACE0( _T("Redirecting STDOUT failed\n") );
		return FALSE;
	}
   
	// Create noninheritable read handle and close the inheritable read handle. 
    fSuccess = DuplicateHandle( GetCurrentProcess(), hChildStdoutRd,
        GetCurrentProcess(),  &hChildStdoutRdDup , 
		0,  FALSE,
        DUPLICATE_SAME_ACCESS );
	if( !fSuccess )
	{
		TRACE0( _T("DuplicateHandle failed\n") );
        return FALSE;
	}
	CloseHandle( hChildStdoutRd );
	
	// The steps for redirecting child process's STDIN: 
	//     1.  Save current STDIN, to be restored later. 
	//     2.  Create anonymous pipe to be STDIN for child process. 
	//     3.  Set STDIN of the parent to be the read handle to the 
	//         pipe, so it is inherited by the child process. 
	//     4.  Create a noninheritable duplicate of the write handle, 
	//         and close the inheritable write handle.  

	// Save the handle to the current STDIN. 
	hSaveStdin = GetStdHandle(STD_INPUT_HANDLE);  

	// Create a pipe for the child process's STDIN.  
	if( !CreatePipe(&hChildStdinRd, &hChildStdinWr, &saAttr, 0) )
	{
		TRACE0( _T("Stdin pipe creation failed\n") );
		return FALSE;
	}
	// Set a read handle to the pipe to be STDIN.  
	if( !SetStdHandle(STD_INPUT_HANDLE, hChildStdinRd) ) 
	{
		TRACE0( _T("Redirecting Stdin failed\n") );
		return FALSE;
	}
	// Duplicate the write handle to the pipe so it is not inherited.  
	fSuccess = DuplicateHandle(GetCurrentProcess(), hChildStdinWr, 
		GetCurrentProcess(), &hChildStdinWrDup, 
		0, FALSE,                  // not inherited       
		DUPLICATE_SAME_ACCESS ); 
	if( !fSuccess ) 
	{
		TRACE0( _T("DuplicateHandle failed\n") );
		return FALSE;
	}
	CloseHandle(hChildStdinWr);  
	
	// Now create the child process. 
	if( !CreateChildProcess(dwProcessId) )
	{
		TRACE0( _T("CreateChildProcess failed\n") );
		return FALSE;
	}
	// After process creation, restore the saved STDIN and STDOUT.  
	if( !SetStdHandle(STD_INPUT_HANDLE, hSaveStdin) )
	{
		TRACE0( _T("Re-redirecting Stdin failed\n") );
		return FALSE;
	}
	if( !SetStdHandle(STD_OUTPUT_HANDLE, hSaveStdout) )
	{
		TRACE0( _T("Re-redirecting Stdout failed\n") );
		return FALSE;
	}
	/*m_pReadThread = AfxBeginThread( (AFX_THREADPROC)ReadPipeThreadProc,(LPVOID)this );
	if( !m_pReadThread )
	{
		TRACE0( _T("Cannot start read-redirect thread!\n") );
		return FALSE;
	}*/
	return TRUE;
}

BOOL CShellView::CreateChildProcess(DWORD& dwProcessId)
{
	PROCESS_INFORMATION piProcInfo;
	STARTUPINFO siStartInfo;  

	// Set up members of STARTUPINFO structure.  
	ZeroMemory( &siStartInfo, sizeof(STARTUPINFO) );
	siStartInfo.cb = sizeof(STARTUPINFO);  
	
	siStartInfo.dwFlags = STARTF_USESHOWWINDOW |STARTF_USESTDHANDLES;
	siStartInfo.hStdInput = hChildStdinRd;
	siStartInfo.hStdOutput = hChildStdoutWr;
	siStartInfo.hStdError = hChildStdoutWr;
	siStartInfo.wShowWindow = SW_HIDE;
	TCHAR shellCmd[_MAX_PATH];
	if( !GetEnvironmentVariable(_T("ComSpec"), shellCmd, _MAX_PATH) )
		  return FALSE;
#ifdef _UNICODE
	_tcscat( shellCmd, _T(" /U") );
#else	
	_tcscat_s( shellCmd, _T(" /A") );
#endif
	// Create the child process.  
	BOOL ret = CreateProcess( NULL,
			shellCmd,       // applicatin name
			NULL,          // process security attributes 
			NULL,          // primary thread security attributes 
			TRUE,          // handles are inherited 
		    NULL,
			NULL,          // use parent's environment 
			NULL,          // use parent's current directory 
			&siStartInfo,  // STARTUPINFO pointer 
			&piProcInfo);  // receives PROCESS_INFORMATION 
	if( ret )
		dwProcessId = piProcInfo.dwProcessId;
	return ret;
}

void CShellView::WriteToPipe( LPCTSTR line )
{
	DWORD dwWritten;

	WriteFile( hChildStdinWrDup, line, _tcslen(line)*sizeof(TCHAR), 
			&dwWritten, NULL );
}

UINT CShellView::ReadPipeThreadProc( LPVOID pParam )
{
	DWORD dwRead;
	TCHAR chBuf[BUFSIZE]; 
	CShellView* pView = (CShellView*)pParam;

	TRACE0( _T("ReadPipe Thread begin run\n") );
	for( ;; )    
	{ 
		int recv=ReadFile( pView->hChildStdoutRdDup, chBuf, BUFSIZE, &dwRead, NULL);
		if(  recv==0|| dwRead == 0) 
			break; 
		chBuf[dwRead/sizeof(TCHAR)] = _T('\0');
		pView->AddTexts( chBuf );
		pView->m_nLength = pView->GetEditCtrl().SendMessage( WM_GETTEXTLENGTH );
	} 
	CloseHandle( pView ->hChildStdinRd);
	CloseHandle( pView ->hChildStdoutWr);
	CloseHandle( pView ->hChildStdinWrDup );
	CloseHandle( pView ->hChildStdoutRdDup );
	pView->m_pReadThread = NULL;
	pView->dwProcessId = DWORD(-1);
	pView->PostMessage( WM_CLOSE );
	return 1;
}


void CShellView::OnDestroy() 
{
	if( dwProcessId!=DWORD(-1) )
	{
		HANDLE hProcess = OpenProcess( PROCESS_ALL_ACCESS, FALSE, dwProcessId );
		if( hProcess )
		{
			TerminateProcess( hProcess,0 );
			CloseHandle( hProcess );
		}
	}
	if( m_pReadThread )
	{
		TerminateThread( m_pReadThread->m_hThread,0 );
		delete m_pReadThread;
	}
	CEditView::OnDestroy();
}

void CShellView::AddTexts(LPCTSTR string)
{
	MoveToEnd();
	GetEditCtrl().ReplaceSel( string );
}

void CShellView::AddTexts(TCHAR ch)
{
	TCHAR string[2];
	string[0] = ch;
	string[1] = _T('\0');
	AddTexts( (LPCTSTR)string );
}

void CShellView::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags) 
{
	int nPos = GetCurrentPosition();
	if( nChar==8 && nPos<=m_nLength )
		return;
	if( nPos<m_nLength )
		MoveToEnd();
	CEditView::OnChar(nChar, nRepCnt, nFlags);
	if( nChar==13 )
	{
		CString input;
		GetUserInput(input);
		WriteToPipe( input );
	}
}

void CShellView::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags){
	if( nChar==VK_DELETE )
	{
		if( GetCurrentPosition()<m_nLength )
			return;
	}
	CEditView::OnKeyDown(nChar, nRepCnt, nFlags);
}

void CShellView::MoveToEnd()
{
	int nLen = GetEditCtrl().SendMessage( WM_GETTEXTLENGTH );
	GetEditCtrl().SetSel( nLen,nLen );
}

int CShellView::GetCurrentPosition()
{
	GetEditCtrl().SetSel(-1,-1);
	int nstart,nstop;
	GetEditCtrl().GetSel(nstart,nstop);
	return nstart;
}

void CShellView::GetUserInput(CString &input)
{
	int where = GetCurrentPosition();
	HLOCAL hBuffer = GetEditCtrl().GetHandle();
	if( hBuffer )
	{
		LPCTSTR szBuffer = (LPCTSTR)LocalLock(hBuffer);
		if( szBuffer )
		{
			input = CString( szBuffer+m_nLength,(where-m_nLength) );
			LocalUnlock( hBuffer );
		}
	}
}

int CShellView::GetSelLength()
{
	int nstart,nstop;
	GetEditCtrl().GetSel(nstart,nstop);
	return (nstart-nstop);
}

BOOL CShellView::PreCreateWindow(CREATESTRUCT& cs) 
{
	return CEditView::PreCreateWindow(cs);
}

现在发现了一个很严重的问题，我写了个定时器的程序main.cpp，定时周期为100ms。通过开启cmd进程运行main.exe的时候，并不能按照定时器周期输出main.exe 执行的结果，而是过一段时间输出一堆数据。如果进入gdb main .exe ，执行run命令同样是出现相同的问题。如果单独运行main.exe，即不通过自己的项目就没有问题。把周期修改的大一些也不行，所以感觉应该是匿名管道或重定向的问题，或者是开启线程UINT CShellView::ReadPipeThreadProc( LPVOID pParam )的问题，调试程序的时候也是发现过一段时间才能执行到UINT CShellView::ReadPipeThreadProc( LPVOID pParam )里面，不知道空下来的时间程序在干什么。
不知道是怎么回事，现在修改方案也来不及了，没想到会出现这个问题。希望大家可以集思广益，帮助一下

[cr945211]

另外，CreateChildProcess创建进程的时候，定义STARTUPINFO siStartInfo; 参数siStartInfo.wShowWindow = SW_HIDE;，也就是CDM窗口始终为隐藏状态，如果定义成 SW_SHOW就始终为打开状态，请问如何控制该窗口的打开、隐藏，既可以随时打开也可以随时最小化（隐藏）？？

[fhw217]

楼主的程序用的是printf 还是 cout，建议用cout，用printf可能会有不能及时输出的问题。

[cr945211]

引用 2 楼 fhw_bin_dl 的回复:

楼主的程序用的是printf 还是 cout，建议用cout，用printf可能会有不能及时输出的问题。

是这个问题欸！ 我改成了cout果然可以了！谢谢先，为什么啊？？

[fhw217]

可能是缓冲区的问题。 如果用printf 加上下面这句 fflush(stdout);

[fhw217]

每个printf 之后都要加 fflush(stdout);