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 "DmoSink.h"

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

IMPLEMENT_WNDMSG( IBackupSink, WM_SQLDMO_BACKUPPERCCOMPLETE );
IMPLEMENT_WNDMSG( IBackupSink, WM_SQLDMO_BACKUPCOMPLETE     );
IMPLEMENT_WNDMSG( IBackupSink, WM_SQLDMO_BACKUPNEXTMEDIA    );

IBackupSink::IBackupSink( IN HWND hWndNotify  )
		   : m_ulRef( 0 )
		   , m_hWndNotify( hWndNotify )
{
	ASSERT( ::IsWindow( m_hWndNotify ) );
}

STDMETHODIMP IBackupSink::QueryInterface( IN  REFIID  riid, 
										  OUT LPVOID* ppvObj )
{
	ASSERT( ppvObj != NULL );
	if( !ppvObj )
		return ( E_FAIL );

	HRESULT hResult = ( E_NOINTERFACE );
	*ppvObj = NULL;

	if( IsEqualIID( riid, IID_IUnknown ) )
		*ppvObj =  static_cast< IUnknown* >( this );
	else if( IsEqualIID( riid, IID_ISQLDMOBackupSink ) )
		*ppvObj =  static_cast< ISQLDMOBackupSink* >( this );
	
	if( *ppvObj )
	{
		reinterpret_cast< IUnknown* >( *ppvObj )->AddRef();
		hResult = ( S_OK );
	}

	return ( hResult );
}

STDMETHODIMP_( ULONG ) IBackupSink::AddRef( void )
{
	return ::InterlockedIncrement( (PLONG)&m_ulRef );
}

STDMETHODIMP_( ULONG ) IBackupSink::Release( void )
{
	ULONG ulNewRef = ::InterlockedDecrement( (PLONG)&m_ulRef );
	if( ulNewRef <= 0 )
	{
		delete this;
		return ( 0 );
	}

	return ( ulNewRef );
}

STDMETHODIMP IBackupSink::PercentComplete( IN SQLDMO_LPCSTR bstrMessage, 
										   IN LONG lPercent )
{
	ASSERT( ::IsWindow( m_hWndNotify ) );

	::SendMessage( m_hWndNotify, WM_SQLDMO_BACKUPPERCCOMPLETE, 
		(WPARAM)bstrMessage, (LPARAM)lPercent );

	return ( S_OK );
}

STDMETHODIMP IBackupSink::Complete( IN SQLDMO_LPCSTR bstrMessage )
{
	ASSERT( ::IsWindow( m_hWndNotify ) );

	::SendMessage( m_hWndNotify, WM_SQLDMO_BACKUPPERCCOMPLETE, 
		(WPARAM)bstrMessage, (LPARAM)0L );

	return ( S_OK );
}

STDMETHODIMP IBackupSink::NextMedia( IN SQLDMO_LPCSTR bstrMessage )
{
	ASSERT( ::IsWindow( m_hWndNotify ) );

	::SendMessage( m_hWndNotify, WM_SQLDMO_BACKUPNEXTMEDIA, 
		(WPARAM)bstrMessage, (LPARAM)0L );

	return ( S_OK );
}

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

IMPLEMENT_WNDMSG( IServerSink, WM_SQLDMO_CONNECTIONBROKEN  );
IMPLEMENT_WNDMSG( IServerSink, WM_SQLDMO_REMOTELOGINFAILED );
IMPLEMENT_WNDMSG( IServerSink, WM_SQLDMO_SERVERMESSAGE     );

IServerSink::IServerSink( IN HWND hWndNotify  )
			: m_ulRef( 0 )
			, m_hWndNotify( hWndNotify )
{
	ASSERT( ::IsWindow( m_hWndNotify ) );
}

STDMETHODIMP IServerSink::QueryInterface( IN  REFIID  riid, 
										  OUT LPVOID* ppvObj )
{
	ASSERT( ppvObj != NULL );
	if( !ppvObj )
		return ( E_FAIL );

	HRESULT hResult = ( E_NOINTERFACE );
	*ppvObj = NULL;

	if( IsEqualIID( riid, IID_IUnknown ) )
		*ppvObj =  static_cast< IUnknown* >( this );
	else if( IsEqualIID( riid, IID_ISQLDMOServerSink ) )
		*ppvObj =  static_cast< ISQLDMOServerSink* >( this );

	if( *ppvObj )
	{
		reinterpret_cast< IUnknown* >( *ppvObj )->AddRef();
		hResult = ( S_OK );
	}

	return ( hResult );
}

STDMETHODIMP_( ULONG ) IServerSink::AddRef( void )
{
	return ::InterlockedIncrement( (PLONG)&m_ulRef );
}

STDMETHODIMP_( ULONG ) IServerSink::Release( void )
{
	ULONG ulNewRef = ::InterlockedDecrement( (PLONG)&m_ulRef );
	if( ulNewRef <= 0 )
	{
		delete this;
		return ( 0 );
	}

	return ( ulNewRef );
}

STDMETHODIMP IServerSink::CommandSent( IN SQLDMO_LPCSTR /*bstrSQL*/ )
{
	return ( E_NOTIMPL );
}

STDMETHODIMP IServerSink::ConnectionBroken( IN  SQLDMO_LPCSTR bstrMsg, 
											OUT LPBOOL pbRetry )
{
	ASSERT( ::IsWindow( m_hWndNotify ) );
	ASSERT( pbRetry != NULL );

	::SendMessage( m_hWndNotify, WM_SQLDMO_CONNECTIONBROKEN, 
		(WPARAM)bstrMsg, (LPARAM)0L );

	*pbRetry = ( TRUE );
	return ( S_OK );
}

// The QueryTimeout event is reserved for future use

STDMETHODIMP IServerSink::QueryTimeout( IN  SQLDMO_LPCSTR /*bstrMsg*/, 
										OUT LPBOOL /*pbCont*/ )
{
	return ( E_NOTIMPL );
}

STDMETHODIMP IServerSink::RemoteLoginFailed( IN LONG /*lSev*/, 
											 IN LONG /*lMsgNum*/,
											 IN LONG /*lMsgState*/,
											 IN SQLDMO_LPCSTR bstrMsg )
{
	ASSERT( ::IsWindow( m_hWndNotify ) );

	::SendMessage( m_hWndNotify, WM_SQLDMO_REMOTELOGINFAILED, 
		(WPARAM)bstrMsg, (LPARAM)0L );

	return ( S_OK );
}

STDMETHODIMP IServerSink::ServerMessage( IN LONG /*lSev*/, 
										 IN LONG /*lMsgNum*/,
										 IN LONG /*lMsgState*/,
										 IN SQLDMO_LPCSTR bstrMsg )
{
	ASSERT( ::IsWindow( m_hWndNotify ) );

	::SendMessage( m_hWndNotify, WM_SQLDMO_SERVERMESSAGE, 
		(WPARAM)bstrMsg, (LPARAM)0L );

	return ( S_OK );
}

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