作用域指针

当我们并不打算复制智能指针，仅仅是想保证被分配的资源将被正确地回收，能够採用一种简单得多的解决方式：作用域指针。例如以下演示样例代码：

template <typename T>
class ScopedPtr
{
public:
	explicit ScopedPtr(T* p = NULL)
		:ptr_(p)
	{
	}

	ScopedPtr<T>& operator=(T* p)
	{
		if(ptr_ != p)
		{
			delete ptr_;
			ptr_ = p;
		}
		return *this;
	}

	~ScopedPtr()
	{
		delete ptr_;
	}
	T* Get() const
	{
		return ptr_;
	}

	T* operator->()const
	{
		SCPP_TEST_ASSERT(ptr_ != NULL,
			"Attempt to use operator -> on NULL pointer.");
		return ptr_;
	}

	T& operator*()const
	{
		SCPP_TEST_ASSERT(ptr_ != NULL,
			"Attempt to use operator * on NULL pointer.");
		return *ptr_;
	}

	//把全部对象的全部权释放给调用者
	T* Release()
	{
		T* p = ptr_;
		ptr_ = NULL;
		return p;
	}

private:
	T* ptr_;

	//复制被禁止
	ScopedPtr(const ScopedPtr<T>& rhs);
	ScopedPtr<T>& operator=(const ScopedPtr<T>& rhs);
};