我有一个名为 Curve 的抽象基类。从它继承了三个类：
- 单曲线
- 多曲线
- CurveShift，它“移动”从 Curve 派生的任何内容（在其构造函数中采用 boost::shared_ptr）
我有一个内存中跟踪所有曲线的存储库，我们称之为 CurveStore。它是作为带有 std::map 的单例实现的。 > 里面。
我的问题出在 CurveShift 上。我想使用 boost::weak_ptr 来引用它正在移动的底层Curve。这样，如果底层 Curve 消失，CurveShift 将无法获得 lock() 并且我会知道 < code>CurveShift 无效。问题在于，在 CurveShift 的简单实现中，每次访问成员函数之一时都尝试获取 lock()，这会显着降低性能。是否有一种标准方法/“模式”来避免在所有成员函数中执行 lock() ？
I have an abstract base class called Curve. There are three classes that inherit from it:
- SingleCurve
- MultiCurve
- CurveShift, which "shifts" anything that derives from Curve (takes a boost::shared_ptr<Curve> in its constructor)
I have a repository in memory that keeps track of all the curves, let's call it CurveStore. It is implemented as a singleton with a std::map<std::string, boost::shared_ptr<Curve> > inside of it.
My problem is with CurveShift. I want to use a boost::weak_ptr to reference the underlying Curve it is shifting. This way, should the underlying Curve go away, the CurveShift will not be able to get a lock() and I will know that the CurveShift is invalid. The problem is that in the naive implementation of CurveShift, where you try to get a lock() every time you access one of the member functions, it degrades performance significantly. Is there a standard way/"pattern" to avoid having to do a lock() in all the member functions?
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“模式”将是“外部/内部函数”（不是官方名称），其中外部函数（公共）锁定weak_ptr，内部函数（私有）采用shared_ptr&作为参数。仅当您拥有一个真正让对象执行某些操作的精益接口（而不是 getter/setter 接口）时，这才会有帮助
The "pattern" would be "external/internal functions" (not an official name), where the external functions (public), lock the weak_ptr's and the internal functions (private) take a shared_ptr& as parameter. This only helps if you have a lean interface that actually lets the object do something (not a getter/setter interface)
设计非常奇怪且薄弱。 （但是大多数基于weak_something的设计都很奇怪，而且很弱。）
你真的想要这种弱行为吗？
我建议您将设计更改为不包含 null
CurveShift对象：每当Curve被销毁时，请删除依赖于它的所有对象。这样，您就不需要任何weak_ptr。Very strange, and weak, design. (But most designs based on weak_something are strange, and weak.)
Do you really want this weak behaviour?
I suggest that you change your design to not have null
CurveShiftobject: whenever aCurveis destroyed, remove all objects that depend on it. This way, you don't need anyweak_ptr.