> 30.03.2011 21:45, Vlad Khorsun wrote:
>
>>> What would do a detach/commit/etc in an object when refcount> 1?
>>
>> Call corresponding method of real object. And not touch refcount.
>>
>>> What would do a detach/commit/etc in an object when refcount = 1?
>>
>> Same as above.
>
> Sorry for ignorance, but why refcount is not decremented in these cases?
To protect us from the more then one call of detach() for the same
instance.
Example :
IAttachment *att = provider->attach(...);
doSomething(att);
att->detach();
doSomething(IAttachment *att)
{
if (something very bad happens) // this could be really at the few
levels
att->detach(); // deeper at whole call stack
}
Well, we can decrement refcount in detach() on success only, but it sounds
as (not necessary) complication of reference counting policy.
> I mean, what is the point in requiring an extra release() call if the
> user has explicitly stated that he no longer needs an object. Note that
> we don't require an explicit addRef() call when the object gets created.
I understand your concerns. BTW, changing way to create objects from
IAttachment *attach(...)
by
void attach(..., **IAttachment)
allows us to use smart pointers and make no additional call of release() :
{
smart_ptr<IAttachment> att = NULL;
provider->attach(..., att.refPtr()); // refcnt == 1 here !
doSomething(att);
att->detach(); // refcnt == 1
} // ~smart_ptr will decrement refcnt
Regards,
Vlad
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