Real-Time Console Output Redirection

// DemoDlg.cpp : implementation file
//

#include "stdafx.h"
#include "Demo.h"
#include "DemoDlg.h"

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

/////////////////////////////////////////////////////////////////////////////
// CDemoDlg dialog

CDemoDlg::CDemoDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CDemoDlg::IDD, pParent)
{
	//{{AFX_DATA_INIT(CDemoDlg)
		// NOTE: the ClassWizard will add member initialization here
	//}}AFX_DATA_INIT
	// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CDemoDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CDemoDlg)
	DDX_Control(pDX, IDC_LOG, m_log);
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CDemoDlg, CDialog)
	//{{AFX_MSG_MAP(CDemoDlg)
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_GO, OnGo)
	ON_BN_CLICKED(IDC_GO2, OnGo2)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CDemoDlg message handlers

BOOL CDemoDlg::OnInitDialog()
{
	CDialog::OnInitDialog();

	// Set the icon for this dialog.  The framework does this automatically
	//  when the application's main window is not a dialog
	SetIcon(m_hIcon, TRUE);			// Set big icon
	SetIcon(m_hIcon, FALSE);		// Set small icon
	
	// TODO: Add extra initialization here
	
	return TRUE;  // return TRUE  unless you set the focus to a control
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CDemoDlg::OnPaint() 
{
	if (IsIconic())
	{
		CPaintDC dc(this); // device context for painting

		SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

		// Center icon in client rectangle
		int cxIcon = GetSystemMetrics(SM_CXICON);
		int cyIcon = GetSystemMetrics(SM_CYICON);
		CRect rect;
		GetClientRect(&rect);
		int x = (rect.Width() - cxIcon + 1) / 2;
		int y = (rect.Height() - cyIcon + 1) / 2;

		// Draw the icon
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CDialog::OnPaint();
	}
}

// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CDemoDlg::OnQueryDragIcon()
{
	return (HCURSOR) m_hIcon;
}


// The following function is a shortened variant of Q190351 - HOWTO: Spawn Console Processes with Redirected Standard Handles
// There is no special magic here, and this version doesn't address issues like:
// - redirecting Input handle
// - spawning 16-bits process (well, RTconsole is a 32-bit process anyway so it should solve the problem)
// - command-line limitations (unsafe 1024-char buffer)
// So you might want to use more advanced versions such as the ones you can find on CodeProject
HANDLE SpawnAndRedirect(LPCTSTR commandLine, HANDLE *hStdOutputReadPipe, LPCTSTR lpCurrentDirectory)
{
	HANDLE hStdOutputWritePipe, hStdOutput, hStdError;
	CreatePipe(hStdOutputReadPipe, &hStdOutputWritePipe, NULL, 0);	// create a non-inheritable pipe
	DuplicateHandle(GetCurrentProcess(), hStdOutputWritePipe,
								GetCurrentProcess(), &hStdOutput,	// duplicate the "write" end as inheritable stdout
								0, TRUE, DUPLICATE_SAME_ACCESS);
	DuplicateHandle(GetCurrentProcess(), hStdOutput,
								GetCurrentProcess(), &hStdError,	// duplicate stdout as inheritable stderr
								0, TRUE, DUPLICATE_SAME_ACCESS);
	CloseHandle(hStdOutputWritePipe);								// no longer need the non-inheritable "write" end of the pipe

	PROCESS_INFORMATION pi;
	STARTUPINFO si;
	ZeroMemory(&si, sizeof(STARTUPINFO));
	si.cb = sizeof(STARTUPINFO);
	si.dwFlags = STARTF_USESTDHANDLES|STARTF_USESHOWWINDOW;
	si.hStdInput  = GetStdHandle(STD_INPUT_HANDLE);	// (this is bad on a GUI app)
	si.hStdOutput = hStdOutput;
	si.hStdError  = hStdError;
	si.wShowWindow = SW_HIDE;						// IMPORTANT: hide subprocess console window
	TCHAR commandLineCopy[1024];					// CreateProcess requires a modifiable buffer
	_tcscpy(commandLineCopy, commandLine);
	if (!CreateProcess(	NULL, commandLineCopy, NULL, NULL, TRUE,
						CREATE_NEW_CONSOLE, NULL, lpCurrentDirectory, &si, &pi))
	{
		CloseHandle(hStdOutput);
		CloseHandle(hStdError);
		CloseHandle(*hStdOutputReadPipe);
		*hStdOutputReadPipe = INVALID_HANDLE_VALUE;
		return NULL;
	}

	CloseHandle(pi.hThread);
	CloseHandle(hStdOutput);
	CloseHandle(hStdError);
	return pi.hProcess;
}

void CDemoDlg::Go(LPCTSTR commandLine)
{
	m_log.SetWindowText(NULL);
	HANDLE hOutput, hProcess;
	hProcess = SpawnAndRedirect(commandLine, &hOutput, NULL);
	if (!hProcess) return;
	m_log.SetWindowText("Child started ! Receiving output pipe :\r\n");
	m_log.SetSel(MAXLONG, MAXLONG);
	m_log.RedrawWindow();
	
	// (in a real program, you would put the following in a separate thread so your GUI thread is not blocked)
	BeginWaitCursor();
	CHAR buffer[65];
	DWORD read;
	while (ReadFile(hOutput, buffer, 64, &read, NULL))
	{
		buffer[read] = '\0';
		m_log.ReplaceSel(buffer);
	}
	CloseHandle(hOutput);
	CloseHandle(hProcess);
	EndWaitCursor();
}

void CDemoDlg::OnGo() 
{
	// spawn console program directly
	Go("\"DemoConsole.exe\"");
}

void CDemoDlg::OnGo2() 
{
	// spawn RTconsole.exe, passing it the command-line to run the console program
	Go("\"RTconsole.exe\"  \"DemoConsole.exe\"");
}