Bug 158529 – Improve code generator for functions with variadic parameters

• Component: Bindings
• Status: RESOLVED FIXED

[Nael Ouedraogo]

Improve code generator for functions with variadic parameters.

[Nael Ouedraogo]

Created attachment 280811 [details]
Patch

[Nael Ouedraogo]

JS bindings code generated with variadic parameters can be improved as proposed in the uploaded patch.
A further possible improvement is to avoid using a Vector of pointers since each item is checked to be not null before being append to the Vector. I would like to use a Vector of "references" instead.
One solution would be to use a Vector of std::reference_wrapper<T>. Is there another solution ?

It seems that variadic parameters are not correctly supported in ObjC and GObject code generators. A test is added to skip functions with variadic.

[Darin Adler]

Comment on attachment 280811 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=280811&action=review

> Source/WebCore/bindings/scripts/CodeGeneratorJS.pm:3666
> +                push(@$outputArray, "    $name.reserveInitialCapacity(state->argumentCount() - $argumentIndex);\n");

Do we have an ironclad guarantee that argumentCount() is >= $argumentIndex? It‘s critical that we know that’s guaranteed, because if not this will try to reserve a colossal capacity.

[Nael Ouedraogo]

> Do we have an ironclad guarantee that argumentCount() is >= $argumentIndex?
> It‘s critical that we know that’s guaranteed, because if not this will try
> to reserve a colossal capacity.

Thanks for the review. 

Actually, we have no guarantee. It may happen when a variadic parameter is preceded by an optional parameter. This issue is also observed in toNativeArguments(). 

I will modify JS code generator so that it dies when an optional parameter is preceding a variadic. I will also add an assert before call to reserveInitialCapacity().

I am going to land a new patch with these modifications.

[Nael Ouedraogo]

Created attachment 281170 [details]
Patch for landing

[WebKit Commit Bot]

Comment on attachment 281170 [details]
Patch for landing

Clearing flags on attachment: 281170

Committed r201988: <http://trac.webkit.org/changeset/201988>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.