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barback/lib/src/graph/static_asset_cascade.dart

-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library barback.graph.static_asset_cascade;
-
-import 'dart:async';
-
-import '../asset/asset_id.dart';
-import '../asset/asset_node.dart';
-import '../asset/asset_set.dart';
-import '../errors.dart';
-import '../log.dart';
-import '../package_provider.dart';
-import 'asset_cascade.dart';
-import 'node_status.dart';
-import 'package_graph.dart';
-
-/// An asset cascade for a static package.
-///
-/// A static package is known to have no transformers and no changes to its
-/// assets. This allows this class to lazily and efficiently provide assets to
-/// the rest of the package graph.
-class StaticAssetCascade implements AssetCascade {
-  final String package;
-
-  final PackageGraph graph;
-
-  /// All sources that have been requested from the provider.
-  final _sources = new Map<AssetId, Future<AssetNode>>();
-
-  StaticAssetCascade(this.graph, this.package);
-
-  Stream<BarbackException> get errors => _errorsController.stream;
-  final _errorsController =
-      new StreamController<BarbackException>.broadcast(sync: true);
-
-  final status = NodeStatus.IDLE;
-
-  final onLog = new StreamController<LogEntry>.broadcast().stream;
-  final onStatusChange = new StreamController<LogEntry>.broadcast().stream;
-  final onAsset = new StreamController<AssetNode>.broadcast().stream;
-
-  Future<AssetSet> get availableOutputs {
-    var provider = graph.provider as StaticPackageProvider;
-    return provider.getAllAssetIds(package).asyncMap(provider.getAsset).toList()
-        .then((assets) => new AssetSet.from(assets));
-  }
-
-  Future<AssetNode> getAssetNode(AssetId id) {
-    return _sources.putIfAbsent(id, () {
-      return graph.provider.getAsset(id).then((asset) {
-        return new AssetNodeController.available(asset).node;
-      }).catchError((error, stackTrace) {
-        if (error is! AssetNotFoundException) {
-          reportError(new AssetLoadException(id, error, stackTrace));
-        }
-
-        // TODO(nweiz): propagate error information through asset nodes.
-        return null;
-      });
-    });
-  }
-
-  void updateSources(Iterable<AssetId> sources) =>
-      throw new UnsupportedError("Static package $package can't be explicitly "
-          "provided sources.");
-
-  void removeSources(Iterable<AssetId> sources) =>
-      throw new UnsupportedError("Static package $package can't be explicitly "
-          "provided sources.");
-
-  void updateTransformers(Iterable<Iterable> transformersIterable) =>
-      throw new UnsupportedError("Static package $package can't have "
-          "transformers.");
-
-  void forceAllTransforms() {}
-
-  void reportError(BarbackException error) => _errorsController.add(error);
-
-  String toString() => "static cascade for $package";
-}