[Accessibility-ia2] IEnumVARIANT vs arrays

Alexander Surkov surkov.alexander at gmail.com
Mon Mar 5 03:34:26 UTC 2012


This sounds like a good option with me. The call costs should be lower
than in IEnumVariant approach. But if you in 99% percents you need
only one target shouldn't we have a method for this to avoid array
stuffs?

Thank you.
Alex.


On Mon, Mar 5, 2012 at 10:56 AM, James Teh <jamie at nvaccess.org> wrote:
> Hi.
>
> Mick and I were discussing this same issue this morning. We haven't seen use
> cases ourselves where there is a need for multiple targets for a given
> relation type, though I'm sure that there are rare use cases; e.g. one
> object which controls multiple objects, etc. Even where there are multiple
> targets, I can't think of a use case where a client would want to retrieve
> them one by one; it's probably going to be one or all. Therefore, I think
> something like the following makes the most sense:
>
>  [propget] HRESULT relationTargetsOfType
>  (
>    [in] BSTR type,
>    [in] long requestedTargets,
>    [out, size_is(,*nTargets,)] IUnknown ***targets,
>    [out, retval] long *nTargets
>  );
> requestedTargets specifies the number of targets requested by the client. If
> 0, all targets will be returned. This allows a client to easily retrieve
> just the first target (or first n targets). nTargets is always set to the
> number of targets returned.
>
> Jamie
>
>
> On 5/03/2012 11:36 AM, Pete Brunet wrote:
>>
>> IATable2::selectedCells/Columns/Rows returns an array but the proposed
>> new methods:
>>
>> https://wiki.mozilla.org/Accessibility/IA2_1.3#Relations
>> https://wiki.mozilla.org/Accessibility/IA2_1.3#Hyperlinks_from_hypertext
>>
>> specify the return of an IEnumVARIANT.
>>
>> What is the reasoning for that? With the IEnumVARIANT you have to fetch
>> the count (so you can allocate an array), the enumerator, and then the
>> elements, taking at least three calls (or more if you want to fetch the
>> elements one at a time). With the alternative approach we had used for
>> IATable2 there is only one call.
>>
>> --
>> *Pete Brunet*
>>
>>
>> a11ysoft - Accessibility Architecture and Development
>> (512) 467-4706 (work), (512) 689-4155 (cell)
>> Skype: pete.brunet
>> IM: ptbrunet (AOL, Google), ptbrunet at live.com (MSN)
>> http://www.a11ysoft.com/about/
>> Ionosphere: WS4G
>>
>>
>> _______________________________________________
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>
>
> --
> James Teh
> Director, NV Access Limited
> Email: jamie at nvaccess.org
> Web site: http://www.nvaccess.org/
> Phone: +61 7 5667 8372
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