Load instances of the same transformer from the same isolate.

sdk/lib/_internal/pub/lib/src/barback.dart

Index: sdk/lib/_internal/pub/lib/src/barback.dart
diff --git a/sdk/lib/_internal/pub/lib/src/barback.dart b/sdk/lib/_internal/pub/lib/src/barback.dart
index 111b7689257095c526c9cc136a97891735915a74..7ad499f8306e2e88d30ad8157b2ced10028d353c 100644
--- a/sdk/lib/_internal/pub/lib/src/barback.dart
+++ b/sdk/lib/_internal/pub/lib/src/barback.dart
@@ -4,14 +4,9 @@
 
 library pub.barback;
 
-import 'dart:async';
-
 import 'package:barback/barback.dart';
-import 'package:collection/collection.dart';
 import 'package:path/path.dart' as p;
 
-import 'io.dart';
-import 'utils.dart';
 import 'version.dart';
 
 /// The currently supported versions of the Barback package that this version of
@@ -38,199 +33,6 @@ import 'version.dart';
 /// [compat]: https://gist.github.com/nex3/10942218
 final supportedVersions = new VersionConstraint.parse(">=0.13.0 <0.14.2");
 
-/// A list of the names of all built-in transformers that pub exposes.
-const _BUILT_IN_TRANSFORMERS = const ['\$dart2js'];
-
-/// An identifier for a transformer and the configuration that will be passed to
-/// it.
-///
-/// It's possible that the library identified by [this] defines multiple
-/// transformers. If so, [configuration] will be passed to all of them.
-class TransformerId {
-  /// The package containing the library where the transformer is defined.
-  final String package;
-
-  /// The `/`-separated path to the library that contains this transformer.
-  ///
-  /// This is relative to the `lib/` directory in [package], and doesn't end in
-  /// `.dart`.
-  ///
-  /// This can be null; if so, it indicates that the transformer(s) should be
-  /// loaded from `lib/transformer.dart` if that exists, and `lib/$package.dart`
-  /// otherwise.
-  final String path;
-
-  /// The configuration to pass to the transformer.
-  ///
-  /// Any pub-specific configuration (i.e. keys starting with "$") will have
-  /// been stripped out of this and handled separately. This will be an empty
-  /// map if no configuration was provided.
-  final Map configuration;
-
-  /// The primary input inclusions.
-  ///
-  /// Each inclusion is an asset path. If this set is non-empty, than *only*
-  /// matching assets are allowed as a primary input by this transformer. If
-  /// `null`, all assets are included.
-  ///
-  /// This is processed before [excludes]. If a transformer has both includes
-  /// and excludes, then the set of included assets is determined and assets
-  /// are excluded from that resulting set.
-  final Set<String> includes;
-
-  /// The primary input exclusions.
-  ///
-  /// Any asset whose pach is in this is not allowed as a primary input by
-  /// this transformer.
-  ///
-  /// This is processed after [includes]. If a transformer has both includes
-  /// and excludes, then the set of included assets is determined and assets
-  /// are excluded from that resulting set.
-  final Set<String> excludes;
-
-  /// Whether this ID points to a built-in transformer exposed by pub.
-  bool get isBuiltInTransformer => package.startsWith('\$');
-
-  /// Returns whether this id excludes certain asset ids from being processed.
-  bool get hasExclusions => includes != null || excludes != null;
-
-  /// Parses a transformer identifier.
-  ///
-  /// A transformer identifier is a string of the form "package_name" or
-  /// "package_name/path/to/library". It does not have a trailing extension. If
-  /// it just has a package name, it expands to lib/transformer.dart if that
-  /// exists, or lib/${package}.dart otherwise. Otherwise, it expands to
-  /// lib/${path}.dart. In either case it's located in the given package.
-  factory TransformerId.parse(String identifier, Map configuration) {
-    if (identifier.isEmpty) {
-      throw new FormatException('Invalid library identifier: "".');
-    }
-
-    var parts = split1(identifier, "/");
-    if (parts.length == 1) {
-      return new TransformerId(parts.single, null, configuration);
-    }
-
-    return new TransformerId(parts.first, parts.last, configuration);
-  }
-
-  factory TransformerId(String package, String path, Map configuration) {
-    parseField(key) {
-      if (!configuration.containsKey(key)) return null;
-      var field = configuration.remove(key);
-
-      if (field is String) return new Set<String>.from([field]);
-
-      if (field is List) {
-        var nonstrings = field
-            .where((element) => element is! String)
-            .map((element) => '"$element"');
-
-        if (nonstrings.isNotEmpty) {
-          throw new FormatException(
-              '"$key" list field may only contain strings, but contained '
-              '${toSentence(nonstrings)}.');
-        }
-
-        return new Set<String>.from(field);
-      } else {
-        throw new FormatException(
-            '"$key" field must be a string or list, but was "$field".');
-      }
-    }
-
-    var includes = null;
-    var excludes = null;
-
-    if (configuration == null) {
-      configuration = {};
-    } else {
-      // Don't write to the immutable YAML map.
-      configuration = new Map.from(configuration);
-
-      // Pull out the exclusions/inclusions.
-      includes = parseField("\$include");
-      excludes = parseField("\$exclude");
-
-      // All other keys starting with "$" are unexpected.
-      var reservedKeys = configuration.keys
-          .where((key) => key is String && key.startsWith(r'$'))
-          .map((key) => '"$key"');
-
-      if (reservedKeys.isNotEmpty) {
-        throw new FormatException(
-            'Unknown reserved ${pluralize('field', reservedKeys.length)} '
-            '${toSentence(reservedKeys)}.');
-      }
-    }
-
-    return new TransformerId._(package, path, configuration,
-        includes, excludes);
-  }
-
-  TransformerId._(this.package, this.path, this.configuration,
-      this.includes, this.excludes) {
-    if (!package.startsWith('\$')) return;
-    if (_BUILT_IN_TRANSFORMERS.contains(package)) return;
-    throw new FormatException('Unsupported built-in transformer $package.');
-  }
-
-  bool operator==(other) => other is TransformerId &&
-      other.package == package &&
-      other.path == path &&
-      const DeepCollectionEquality().equals(other.configuration, configuration);
-
-  int get hashCode => package.hashCode ^ path.hashCode ^
-      const DeepCollectionEquality().hash(configuration);
-
-  String toString() => path == null ? package : '$package/$path';
-
-  /// Returns the asset id for the library identified by this transformer id.
-  ///
-  /// If `path` is null, this will determine which library to load.
-  Future<AssetId> getAssetId(Barback barback) {
-    if (path != null) {
-      return new Future.value(new AssetId(package, 'lib/$path.dart'));
-    }
-
-    var transformerAsset = new AssetId(package, 'lib/transformer.dart');
-    return barback.getAssetById(transformerAsset).then((_) => transformerAsset)
-        .catchError((e) => new AssetId(package, 'lib/$package.dart'),
-            test: (e) => e is AssetNotFoundException);
-  }
-
-  /// Returns the path to the library identified by this transformer within
-  /// [packageDir], which should be the directory of [package].
-  ///
-  /// If `path` is null, this will determine which library to load. Unlike
-  /// [getAssetId], this doesn't take generated assets into account; it's used
-  /// to determine transformers' dependencies, which requires looking at files
-  /// on disk.
-  String getFullPath(String packageDir) {
-    if (path != null) return p.join(packageDir, 'lib', p.fromUri('$path.dart'));
-
-    var transformerPath = p.join(packageDir, 'lib', 'transformer.dart');
-    if (fileExists(transformerPath)) return transformerPath;
-    return p.join(packageDir, 'lib', '$package.dart');
-  }
-
-  /// Returns whether the include/exclude rules allow the transformer to run on
-  /// [pathWithinPackage].
-  ///
-  /// [pathWithinPackage] must be a URL-style path relative to the containing
-  /// package's root directory.
-  bool canTransform(String pathWithinPackage) {
-    // TODO(rnystrom): Support globs in addition to paths. See #17093.
-    if (excludes != null) {
-      // If there are any excludes, it must not match any of them.
-      if (excludes.contains(pathWithinPackage)) return false;
-    }
-
-    // If there are any includes, it must match one of them.
-    return includes == null || includes.contains(pathWithinPackage);
-  }
-}
-
 /// Converts [id] to a "package:" URI.
 ///
 /// This will throw an [ArgumentError] if [id] doesn't represent a library in