/**
 * @file XTPSingleton.cpp
 *
 * @copyright
 * (c) 1998-2025 Codejock Software, All Rights Reserved.
 *
 * This source file is the property of Codejock Software and must not be
 * redistributed by any means without the explicit written permission of
 * Codejock Software.
 *
 * The use of this source code is governed by the terms and conditions specified
 * in the Toolkit Pro license agreement. Codejock Software grants you, as a
 * single software developer, the limited right to use this software on one
 * computer only.
 *
 * Contact Information:
 * support@codejock.com
 * http://www.codejock.com
 *
 */

#include "stdafx.h"

#include "Common/XTPTypeId.h"
#include "Common/XTPSynchro.h"
#include "Common/XTPSystemHelpers.h"
#include "Common/XTPApplication.h"
#include "Common/XTPSingleton.h"

#include "Common/Base/Diagnostic/XTPDisableNoisyWarnings.h"

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

CXTPSingletonPointer::CXTPSingletonPointer(SIZE_T cbObjectSize, Creator pfnCreator,
										   Destroyer pfnDestroyer,
										   Initializer pfnInitializer /*= NULL*/)
	: m_pInstance(NULL)
	, m_cbObjectSize(cbObjectSize)
	, m_pfnCreator(pfnCreator)
	, m_pfnDestroyer(pfnDestroyer)
	, m_bDestroyed(FALSE)
{
	_ASSERTE(1 <= m_cbObjectSize);
	_ASSERTE(NULL != m_pfnCreator);
	_ASSERTE(NULL != m_pfnDestroyer);

	if (NULL != pfnInitializer)
	{
		pfnInitializer();
	}

	::InitializeCriticalSection(&m_access);

	XTPAccessExclusive(XTPGetApplication())->Subscribe(this);
}

CXTPSingletonPointer::~CXTPSingletonPointer()
{
	Destroy();
	::DeleteCriticalSection(&m_access);
}

void* CXTPSingletonPointer::GetInstance()
{
	_ASSERTE(!m_bDestroyed);
	if (m_bDestroyed)
	{
		AfxThrowMemoryException();
	}

	if (NULL == m_pInstance)
	{
		::EnterCriticalSection(&m_access);

		if (NULL == m_pInstance)
		{
			XTP_GUARD_EXCLUSIVE_(CXTPApplication, XTPGetApplication(), pApp)
			{
				BOOL bAppReady = pApp->IsReady();
				_ASSERTE("The main application object has not been initialized yet or has been "
						 "destroyed already. A common cause of this condition is that the main "
						 "application class is not derived from CXTPWinApp or XTPInitialize has "
						 "not been called instead. Refer to CXTPWinApp and XTPInitialize "
						 "documentation for more details. The application will abort now."
						 && bAppReady);

				if (!bAppReady)
					abort();

				// It is necessary to use low level API at this point
				// as runtime might not be initialized properly for 'new' or 'malloc'.
				m_pInstance = ::HeapAlloc(::GetProcessHeap(), HEAP_ZERO_MEMORY, m_cbObjectSize);

				if (NULL != m_pInstance)
				{
					if (!m_pfnCreator(m_pInstance))
					{
						::HeapFree(::GetProcessHeap(), 0, m_pInstance);
						m_pInstance = NULL;
					}
				}
			}
		}

		::LeaveCriticalSection(&m_access);

		if (NULL == m_pInstance)
		{
			AfxThrowMemoryException();
		}
	}

	return m_pInstance;
}

void CXTPSingletonPointer::Destroy()
{
	if (!m_bDestroyed)
	{
		XTPAccessExclusive(XTPGetApplication())->Unsubscribe(this);

		if (NULL != m_pInstance)
		{
			m_pfnDestroyer(m_pInstance);

			// It is necessary to use low level API at this point
			// as runtime might not be initialized properly for 'delete' or 'free'.
			::HeapFree(::GetProcessHeap(), 0, m_pInstance);

			m_pInstance = NULL;
		}

		m_bDestroyed = TRUE;
	}
}

void CXTPSingletonPointer::OnApplicationShutdown(CXTPApplication* pApplication)
{
	UNREFERENCED_PARAMETER(pApplication);

	Destroy();
}