Re: Loki SmartPtr questions

From: rogeeff (rogeeff_at_[hidden])
Date: 2002-01-12 20:34:03

--- In boost_at_y..., "Andrei Alexandrescu" <andrewalex_at_h...> wrote:
> The proof is in the pudding, but I'll try to reply in short below.
> 
> > 1. Why the separate Storage and Ownership policies?
> 
> They are orthogonal for the most part. For example, there is no 
link between
> the fact that you allocate a pointer with new and the fact that you
> reference count it. Same pointer allocated with new you also may 
want to
> reference link (maintain a linked list between all pointers to the 
same
> object) or simply treat it as an auto_ptr. As far as the ownership 
policy is
> concerned, the managed resource can be allocated anyhow and can 
actually not
> be a pointer at all.
> 

That is not exactly true, cause Clone part belong to Ownership 
Policy, while it may require some knowledge belonging to 
StoragePolicy. For example, how whould you implement DeepCopy smart 
pointer over arrays?
To cut the knot the framework should be enhanced somehow. For example:
If OwnershipPolicy::Clone returns false (you will need to make 
current result a second argument), meaning that it fails to perform a 
clone, than the framework would use StoragePolicy::DeepCopy to 
perform as least deep copy. I am not sure how generic it is and how 
would I like such a solution but we need something like this.

[...]

> Andrei

Gennadiy.