Re: [boost] [Containers] Review

Subject: Re: [boost] [Containers] Review
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2011-08-11 07:16:06

Phil Endecott wrote:
>
> - How about a "batch" or "transaction" object?:
>
> flat_container c;
> {
>    flat_container::insert_batch b(c);
>    b.insert(data1);
>    b.insert(data2);
> } // b's dtor merges new values.

That's an interesting idea, but aren't exceptions possible in merging the new values?  If so, you don't want the dtor doing the work since it can't emit an exception and may not be able to undo the work it began.  Also, if flat_container::insert_batch::insert() or the constructor do anything to c, the dtor should be able to revert those changes unless the merge occurs.

Here's another approach:

flat_container c;
{
   flat_container::insert_batch b(c);
   b.insert(data1);
   b.insert(data2);
   b.merge();
}

That allows the dtor to clean up should an exception occur within the compound statement, including from merge().  Of course it requires explicitly asking that the data be merged rather than doing so automatically.

_____
Rob Stewart                           robert.stewart_at_[hidden]
Software Engineer                     using std::disclaimer;
Dev Tools & Components
Susquehanna International Group, LLP  http://www.sig.com

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