Generate factory providers for systemnative

Generate factory providers for systemnative


BUG=
TEST=

Committed: https://code.google.com/p/dart/source/detail?r=5541

[Anton Muhin, 2012-03-15 13:43:39]

General question (but we should probably commit it as is), why that many levels
of indirection?

Couldn't we have something like that:

DOMInterface default  DOMInterfaceImplementation {
  DOMInterface();
}

DOMInterfaceImplementation {
  factory DOMInterfaceImplementation() native
"DOMInterfaceImplementation_constructor_Callback";
}

Why we need both factory providers and a static helper class?

tia for explanations!

[sra1, 2012-03-15 18:19:40]

On 2012/03/15 13:43:39, antonmuhin wrote:
> General question (but we should probably commit it as is), why that many
levels
> of indirection?
> 
> Couldn't we have something like that:
> 
> DOMInterface default  DOMInterfaceImplementation {
>   DOMInterface();
> }
> 
> DOMInterfaceImplementation {
>   factory DOMInterfaceImplementation() native
> "DOMInterfaceImplementation_constructor_Callback";
> }
> 
> Why we need both factory providers and a static helper class?
> 
> tia for explanations!

The interfaces are generated once for all libraries.  The frog dom (and html)
are single libraries.
In the single library case the factory provider class should be private.  That
prevents it being imported from an impl library, hence the extra hop.

The existing manual code goes to the same degree of effort to put the 'native'
method in the impl library.
I just followed that pattern, but generated one class per static method because
that is simpler.

Do you know for sure if the vm native feature works on factory methods?  I don't
think it does for frog.  Back when dartc was a code generator, it native only
worked properly on static methods.