Shrinking SQL Server Transaction Logs with SQL-DMO

/////////////////////////////////////////////////////////////////////////////
// #ifndef __ARMEN_H__
// #define __ARMEN_H__
//     Central Bank of Armenia, Information Security Department
//	   Armen Hakobyan, 2004. mailto:armen.h@web.am
//	   http://www.codeproject.com/script/articles/list_articles.asp?userid=25653
// #endif // __ARMEN_H__
/////////////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "main.h"

#if ( _ATL_VER < _ATL_VER_70 )
	#include < atlimpl.cpp >
#endif
#include < LmErr.h >

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

void DoEvents( void )
{
	MSG msg = { 0 };
	while ( ::PeekMessage( &msg, NULL, 0, 0, PM_NOREMOVE ) )
	{
		BOOL bRet = ::GetMessage( &msg, NULL, 0, 0 ); 
		if( bRet == -1 )
			continue;   // error, don't process		
		else if( bRet )
		{
			// Before you translate and dispatch you might consider
			// checking if that message does not close you window
			// you should ignore it because if you doevents() in a loop
			// and the user click the close buton it closes !
			// and you loop continues untill it ends:

			if( ( msg.message != WM_DESTROY ) && 
				( msg.message != WM_CLOSE ) &&
			  ( ( msg.message != WM_SYSCOMMAND ) && 
			    ( msg.wParam  != SC_CLOSE ) ) )
			{			
				::TranslateMessage( &msg );
				::DispatchMessage( &msg );				
			}
		}
		else
			break;
	}

	::Sleep( 0 );
}

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

void TrimWorkingSet( void )
{
	// 1. Compact CRT heap
	// 2. Compact process heap
	// 3. Minimize process workingset size

	_heapmin();
	::HeapCompact( ::GetProcessHeap(), 0 );	
	::SetProcessWorkingSetSize( ::GetCurrentProcess(), (DWORD)-1, (DWORD)-1 );
}

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

INT _MessageBoxEx( IN UINT uID, IN UINT uType, ... )
{
	va_list pszArgList = NULL;
	va_start( pszArgList, uType );     /* Initialize variable arguments. */	
	
	TCHAR szFmt[ 1024 ] = { 0 };
	if( AtlLoadString( uID, szFmt, _countof( szFmt ) ) )
	{
		TCHAR szOut[ 1024 ] = { 0 };
		::wvsprintf( szOut, szFmt, pszArgList );

		return _MessageBox( szOut, uType );
	}

	va_end( pszArgList );
	return ( 0 );
}

INT _MessageBox( IN UINT uID, IN UINT uType /*MB_OK | MB_ICONSTOP*/ )
{		
	TCHAR szBuffer[ 1024 ] = { 0 };
	if( AtlLoadString( uID, szBuffer, _countof( szBuffer ) ) )		
		return _MessageBox( szBuffer, uType );

	return ( 0 );
}

INT _MessageBox( IN LPCTSTR pszText, IN UINT uType /*MB_OK | MB_ICONSTOP*/ )
{
	return ::MessageBox( ::GetActiveWindow(), pszText, _Module.s_pszAppName, uType );
}

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

// Not seacrhing just for last ']' occurance because it can also be
// in the user message, not only in the prefix.
// NOT REQUIRED IN DisplayComError, SEE SQLSERVER ODBCPrefix PROPERTY !!!

LPCTSTR SkipODBCPrefix( IN LPCTSTR pszSqlMsg )
{
	// ODBC error message format has prefix [0][1][2][optional 3][optional 4]
	// For example '[Microsoft][ODBC SQL Server Driver][SQL Server][SQL-DMO]...'

	static LPCTSTR sppszPrefixes[ 12 ] = {
		_T( "[Microsoft]"				),	// 0
		_T( "[ODBC Driver Manager]"		),	// 1
		_T( "[ODBC Cursor Library]"		),	// 1
		_T( "[ODBC SQL Server Driver]"	),	// 1
		_T( "[Named Pipes]"				),	// 2
		_T( "[Shared Memory]"			),	// 2
		_T( "[Multiprotocol]"			),	// 2
		_T( "[TCP/IP Sockets]"			),	// 2
		_T( "[NWLink IPX/SPX]"			),	// 2
		_T( "[Banyan VINES]"			),	// 2
		_T( "[SQL Server]"				),	// 3
		_T( "[SQL-DMO]"					)	// 4
	};

	LPCTSTR pszToken  = NULL;
	LPCTSTR pszUsrMsg = NULL;
	LPCTSTR pszTmpPtr = NULL;

	for( INT n = ( _countof( sppszPrefixes ) - 1 ); n >= 0; n-- )
	{
		pszToken  = sppszPrefixes[ n ];
		pszTmpPtr = ::StrRStrI( pszSqlMsg, NULL, pszToken );

		if( pszTmpPtr )
		{
			pszTmpPtr += ::lstrlen ( pszToken );
			pszUsrMsg = pszTmpPtr;
			break;
		}
	}

	return pszSqlMsg; //( pszUsrMsg );
}

void DisplayComError( IN _com_error& e, IN BOOL bExtended )
{
	
	LPTSTR pszMsg = ::StrDup( (LPCTSTR)e.Description() );
	if( !pszMsg )		
		pszMsg = ::StrDup( (LPCTSTR)e.ErrorMessage() );		
	
	TCHAR szMsg[ 1024 ] = { 0 };
	if( !bExtended )
		::lstrcpyn( szMsg, pszMsg, _countof( szMsg ) );		
	else
	{		
		LPCTSTR pszSrc = ::StrDup( (LPCTSTR)_bstr_t( e.Source() ) );
		if( !pszSrc )
			pszSrc = ::StrDup( _Module.s_pszAppName );
        
		::wsprintf(
			szMsg,
			_T( "The program encountered the following error:\n\n" )
			_T( "Number:\t\t%d\n" )
			_T( "Source:\t\t%s\n" )
			_T( "Description:\t%s" ),
			HRESULT_CODE( e.Error() ),
			pszSrc,
			pszMsg
		);

		_localFree( pszSrc );
	}

	_localFree( pszMsg );
	_MessageBox( szMsg );
}

/////////////////////////////////////////////////////////////////////////////
// 
//	FUNCTION:		FormatMessage()
// 
//	PURPOSE:		This function loads a string from a message file and
//					replaces the inserts if necessary (formats).
// 
//	PARAMETERS:		pszMsgDll
//						[ in ] - location of the message file
//					dwMsgCode
//						[ in ] - message identifier for the requested
//						message
//					dwLangID
//						[ in ] - language identifier for the requested
//						message
//					ppszMsg
//						[ out ] - pointer to a pointer variable that 
//						receives a pointer to an allocated, read-only 
//						buffer containing the formatted (and null-terminated)
//						message. Call the ::HeapFree function to free the 
//						buffer when you are finished with it.
//					...
//						[ in ] - Specifies one or more optional arguments. 
//						The number and type of argument parameters depend on 
//						the corresponding format-control specifications that
//						the message file was compiled with. These values are 
//						used as inserts in the formatted message. A %1 in the 
//						format string indicates the first value; a %2 indicates 
///						the second argument; and so on.
// 
//	RETURN VALUE:	Returns last error if fails, ERROR_SUCCESS otherwise.
//					See Win API ::FormatMessage for more information.
//
//	COMMENTS:		1.	Requires #include < LmErr.h >
//					2.	Call the ::HeapFree function to free the ppszMsg
//						buffer when you are finished with it.
//
//	COMPATIBILTY:	Microsoft Windows 95 or later, NT 4.0 or later
//
//	HISTORY:		15 Nov 2002 - first release
//					21 Nov 2002 - replaced ppszArgs with ... ( va_list )
//					22 Nov 2002 - added MSMQ errors processing
//					24 Nov 2002	- removed r�peated message buffer allocation
//
//	LAST REVISION:	24 Nov 2002 by Armen Hakobyan
//
/////////////////////////////////////////////////////////////////////////////

/////////////////////////////////////////////////////////////////////////////
//
//	SAMPLE USAGE:
//
//	// Assuming that the message has format: "%s %s"
//
//	LPTSTR  pszMsg = NULL;
//	LPCTSTR pszArgs[ 2 ] = { _T( "Hello" ), _T( "Armen" ) };
//
//	if( FormatMessage( &pszMsg, MSG_PRINTER_INSTALLED, 
//		pszArgs,  _T( "pmsvcmsg.dll" ), 0 ) )
//	{
//		::MessageBox( ::GetActiveWindow(), pszMsg, 
//			_T( "Sample" ), MB_OK | MB_ICONINFORMATION );
//
//		::HeapFree( ::GetProcessHeap(), 0, pszMsg );
//	}
//
//	// We'll get : "Hello Armen"
//	//				 %s     %s
//
/////////////////////////////////////////////////////////////////////////////

DWORD FormatMessage( IN  LPCTSTR pszMsgDll,
					 IN  DWORD   dwMsgCode,
					 IN  DWORD   dwLangID,					 
					 OUT LPTSTR* ppszMsg,
					 IN  ...			 )
{
	// No check for pszMsgDll, because
	// ::LoadLibraryEx will silently fail later.
	
	ATLASSERT( !::IsBadReadPtr( ppszMsg, sizeof( LPTSTR* ) ) );

	HMODULE hModule = NULL;
	DWORD	dwFlags = FORMAT_MESSAGE_ALLOCATE_BUFFER;

	if( pszMsgDll == NULL )
	{
		if( HRESULT_FACILITY( dwMsgCode ) == FACILITY_MSMQ )		// MSMQ errors only
			pszMsgDll = _T( "mqutil.dll" );
		else if( dwMsgCode >= NERR_BASE && dwMsgCode <= MAX_NERR )	// Get network errors
			pszMsgDll = _T( "netmsg.dll" );
		else														// Get system errors
			dwFlags |= FORMAT_MESSAGE_FROM_SYSTEM;
	}

	if( pszMsgDll != NULL )
	{
		hModule = ::LoadLibraryEx( pszMsgDll, NULL, LOAD_LIBRARY_AS_DATAFILE );
		if( hModule != NULL )
			dwFlags |= FORMAT_MESSAGE_FROM_HMODULE;
		else
			return ::GetLastError();
	}

	va_list pszArgs = NULL;
	va_start( pszArgs, ppszMsg );

	DWORD dwRet = ::FormatMessage( dwFlags, hModule, dwMsgCode, dwLangID, 
		(LPTSTR)ppszMsg, 0, (va_list*)&pszArgs );

	va_end( pszArgs );
	return ( dwRet );
}

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

BOOL CheckDlgItemText( IN HWND hWnd, IN INT nID )
{
	ATLASSERT( IS_INTRESOURCE( nID ) );

	CWindow wndCtl = ::GetDlgItem( hWnd, nID );		
	ATLASSERT( wndCtl.IsWindow() );

	if( wndCtl.GetWindowTextLength() <= 0 )
	{		
		TCHAR szPar[ 256 ] = { 0 };
		if( AtlLoadString( nID, szPar, _countof( szPar ) ) )
			_MessageBoxEx( IDP_INVALID_STR, MB_ICONEXCLAMATION | MB_OK, szPar );
		else
			::MessageBeep( MB_ICONEXCLAMATION );

		wndCtl.SetFocus();
		return ( FALSE );
	}

	return ( TRUE );
}

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

BOOL GetSqlServerPath( IN OUT LPTSTR pszPath, 
					   IN OUT PULONG pulChars, 
					   IN SQL_ROOTS  eRoot )
{
	ATLASSERT( pszPath != NULL );
	ATLASSERT( AtlIsValidString( pszPath, *pulChars ) );

	static LPCTSTR spszKeys[ 2 ] = {
		_T( "SOFTWARE\\Microsoft\\Microsoft SQL Server\\80\\Tools\\ClientSetup" ),
		_T( "SOFTWARE\\Microsoft\\MSSQLServer\\Setup" )
	};

	CRegKey regKey;
	LONG lRetval = regKey.Open( HKEY_LOCAL_MACHINE, spszKeys[ eRoot ] );

	if( lRetval == ERROR_SUCCESS )
	{
		#if defined( _ATL_VER ) && ( _ATL_VER >= _ATL_VER_70 )
			lRetval = regKey.QueryStringValue( _T( "SQLPath" ), pszPath, pulChars );
		#else
			lRetval = regKey.QueryValue( pszPath, _T( "SQLPath" ), pulChars );
		#endif

		return ( lRetval == ERROR_SUCCESS );
	}

	return ( FALSE );
}