在 Gitter 人员的帮助下找到了如何做到这一点。
您必须有一个文件(即使是空的)才能调用生成器。在我的示例中,它是 lib/batch.dart。
来源生成:^0.5.8
这是工作代码:
工具/build.dart
import 'package:build_runner/build_runner.dart';
import 'package:raoni_global/phase.dart';
main() async {
PhaseGroup pg = new PhaseGroup()
..addPhase(batchModelablePhase(const ['lib/batch.dart']));
await build(pg,
deleteFilesByDefault: true);
}
阶段:
batchModelablePhase([Iterable<String> globs =
const ['bin/**.dart', 'web/**.dart', 'lib/**.dart']]) {
return new Phase()
..addAction(
new GeneratorBuilder(const
[const BatchGenerator()], isStandalone: true
),
new InputSet(new PackageGraph.forThisPackage().root.name, globs));
}
发电机:
import 'dart:async';
import 'package:analyzer/dart/element/element.dart';
import 'package:build/build.dart';
import 'package:source_gen/source_gen.dart';
import 'package:glob/glob.dart';
import 'package:build_runner/build_runner.dart';
class BatchGenerator extends Generator {
final String path;
const BatchGenerator({this.path: 'lib/models/*.dart'});
@override
Future<String> generate(Element element, BuildStep buildStep) async {
// this makes sure we parse one time only
if (element is! LibraryElement)
return null;
String libraryName = 'raoni_global', filePath = 'lib/src/model.dart';
String className = 'Modelable';
// find the files at the path designed
var l = buildStep.findAssets(new Glob(path));
// get the type of annotation that we will use to search classes
var resolver = await buildStep.resolver;
var assetWithAnnotationClass = new AssetId(libraryName, filePath);
var annotationLibrary = resolver.getLibrary(assetWithAnnotationClass);
var exposed = annotationLibrary.getType(className).type;
// the caller library' name
String libName = new PackageGraph.forThisPackage().root.name;
await Future.forEach(l.toList(), (AssetId aid) async {
LibraryElement lib;
try {
lib = resolver.getLibrary(aid);
} catch (e) {}
if (lib != null && Utils.isNotEmpty(lib.name)) {
// all objects within the file
lib.units.forEach((CompilationUnitElement unit) {
// only the types, not methods
unit.types.forEach((ClassElement el) {
// only the ones annotated
if (el.metadata.any((ElementAnnotation ea) =>
ea.computeConstantValue().type == exposed)) {
// use it
}
});
});
}
});
return '''
$libName
''';
}
}