angular/modules/angular2/src/transform/directive_linker/transformer.dart

library angular2.transform.directive_linker.transformer;

import 'dart:async';

import 'package:angular2/src/transform/common/asset_reader.dart';
import 'package:angular2/src/transform/common/formatter.dart';
import 'package:angular2/src/transform/common/logging.dart' as log;
import 'package:angular2/src/transform/common/names.dart';
import 'package:barback/barback.dart';

import 'linker.dart';

/// Transformer responsible for processing .ng_deps.dart files created by
/// {@link DirectiveProcessor} and ensuring that the generated calls to
/// `setupReflection` call the necessary `setupReflection` method in all
/// dependencies.
class DirectiveLinker extends Transformer {
  DirectiveLinker();

  @override
  bool isPrimary(AssetId id) => id.path.endsWith(DEPS_EXTENSION);

  @override
  Future apply(Transform transform) async {
    log.init(transform);

    try {
      var reader = new AssetReader.fromTransform(transform);
      var assetId = transform.primaryInput.id;
      var assetPath = assetId.path;
      var transformedCode = await linkNgDeps(reader, assetId);
      if (transformedCode != null) {
        var formattedCode = formatter.format(transformedCode, uri: assetPath);
        transform.addOutput(new Asset.fromString(assetId, formattedCode));
      }
    } catch (ex, stackTrace) {
      log.logger.error('Linking ng directives failed.\n'
          'Exception: $ex\n'
          'Stack Trace: $stackTrace');
    }
    return null;
  }
}

/// Transformer responsible for removing unnecessary `.ng_deps.dart` files
/// created by {@link DirectiveProcessor}.
class EmptyNgDepsRemover extends Transformer {
  EmptyNgDepsRemover();

  @override
  bool isPrimary(AssetId id) => id.path.endsWith(DEPS_EXTENSION);

  @override
  Future apply(Transform transform) async {
    log.init(transform);

    try {
      var reader = new AssetReader.fromTransform(transform);
      if (!(await isNecessary(reader, transform.primaryInput.id))) {
        transform.consumePrimary();
      }
    } catch (ex, stackTrace) {
      log.logger.error('Removing unnecessary ng deps failed.\n'
          'Exception: $ex\n'
          'Stack Trace: $stackTrace');
    }
    return null;
  }
}