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Subject: Re: [boost] [smart ptr] Any interest in copy-on-write pointer for C++11?
From: Jeffrey Yasskin (jyasskin_at_[hidden])
Date: 2013-02-08 16:44:24

On Feb 8, 2013 12:29 PM, "Mathias Gaunard" <mathias.gaunard_at_[hidden]>
> On 08/02/13 18:35, Jeffrey Yasskin wrote:
>> WebKit has a class vaguely like this for your case #2:
>> used at
>> Semantically every copy is a real copy, and, contrary to Mathias'
>> assertion, couldn't be replaced by a move in C++11, but they want to
>> share identical values when doing so is cheap.
> If you want identical values to use the same resource, you should use a
flyweight factory.

I'm sure the WebKit project would welcome a patch demonstrating that
flyweights are a more efficient technique for CSS matching. I don't expect
they are because these values are built up through several mutations, and a
hash table lookup plus a copy on each mutation sounds more expensive than
the current copy-on-write system.


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