//-----------------------------------------------------------------------------+
// Copyright (C), 1998-2007, SH Software Co. Ltd.
// = FileName	:   SafeResource.cpp
// = Version	:   ver2.0
// = Author		:   zjq
// = CreateDate	:   2002-09-09
// = Description:   类的定义
// = Maintainers: 
//                  
//-----------------------------------------------------------------------------+
#include "StdAfx.h"
#include "SafeResource.h"

SafeResource::SafeResource()
{
	pReferCount = new int(1);
}

void SafeResource::Attach(SafeResource&source)
{
	Detach();
	if(source.IsAttached())
	{
		pReferCount=source.pReferCount;
		Apply(source);
		IncreaseRef();
	}
}

SafeResource::SafeResource(SafeResource&source)//获取资源
{
	Attach(source);
}

SafeResource& SafeResource::operator=(SafeResource&source)
{
	//只要不是自身赋值，则获取资源
	//防止自身赋值时引用计数错误增大。
	if ((&source) != this)
	{
		Attach(source);
	}
	return *this;
}

void SafeResource::Detach()
{
	//＜放弃资源＞
	//如是资源的最后一个用户，释放资源。
	//如果资源为空，则不进行任何操作。
	//多次调用完全等同于一次调用。
	if(IsAttached())
	{
		DecreaseRef();
		if(CanRelease())
		{
			Release();
			delete pReferCount;
		}
		pReferCount=NULL;
	}
}

SafeResource::~SafeResource()
{
	//如果子类重载了Apply或者Release,则其析构函数必须调用Detach。
	Detach();
}

void SafeResource::Apply(SafeResource&source)
{

}

void SafeResource::Release()
{

}

void SafeResource::IncreaseRef()
{
	(*pReferCount)++;
}

void SafeResource::DecreaseRef()
{
	(*pReferCount)--;
}

bool SafeResource::CanRelease()
{
	return (*pReferCount) == 0;
}

bool SafeResource::IsLastRefer()
{
	return (*pReferCount) == 1;
}

bool SafeResource::IsAttached()
{
	return pReferCount != NULL;
}