@Natives and @ResourceIdentifier

[dcharkes]

We should consider making @Natives automatically be mapped to @ResourceIdentifiers.

@Natives have a symbol and assetId (both possibly inferred).
https://api.dart.dev/stable/3.3.3/dart-ffi/Native-class.html

@ResourceIdentifiers only have a Object? metadata.
https://pub.dev/documentation/meta/latest/meta/ResourceIdentifier/ResourceIdentifier.html

A possible mapping would be

@Native<>(assetId: 'foo', symbol: 'bar')

->

@ResourceIdentifier({
  'assetId': 'foo',
  'symbol': 'bar',
})

Alternatively, we can make FFIgen generate the resource identifier annotations. Are there any cases where we don't want the resource identifier information? Maybe if a package only supports dylibs, so tree shaking cannot be used anyways, then it should run FFIgen without adding the annotations.

(If we want to do the mapping automatically in the Dart SDK, we should move this issue there. If we want to generate the annotations in FFIgen, we should keep it here.)

cc @mosuem thoughts?

[mosuem]

SGTM - I think I prefer using the approach of adding ResourceIdentifier in ffigen, it makes the process a bit more visible for an otherwise already very opaque feature. Also, it pollutes the resources.json file less.

[dcharkes]

One slight issue is that the assetId might not entirely be obvious when generating.
So maybe assetId should be optional.

Something along the lines of:

# ffigen.yaml
native:
  assetId: package:my_package/src/bindings_generated.dart
  resource-identifers: true