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barback/lib/src/graph/asset_cascade.dart

Index: barback/lib/src/graph/asset_cascade.dart
diff --git a/barback/lib/src/graph/asset_cascade.dart b/barback/lib/src/graph/asset_cascade.dart
deleted file mode 100644
index 70bc4c94b055e27028243ffa4e19b153fd34b87b..0000000000000000000000000000000000000000
--- a/barback/lib/src/graph/asset_cascade.dart
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-// Copyright (c) 2013, 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.asset_cascade;
-
-import 'dart:async';
-
-import '../asset/asset.dart';
-import '../asset/asset_id.dart';
-import '../asset/asset_node.dart';
-import '../asset/asset_set.dart';
-import '../errors.dart';
-import '../log.dart';
-import '../transformer/transformer.dart';
-import '../utils.dart';
-import '../utils/cancelable_future.dart';
-import 'node_status.dart';
-import 'node_streams.dart';
-import 'package_graph.dart';
-import 'phase.dart';
-
-/// The asset cascade for an individual package.
-///
-/// This keeps track of which [Transformer]s are applied to which assets, and
-/// re-runs those transformers when their dependencies change. The transformed
-/// asset nodes are accessible via [getAssetNode].
-///
-/// A cascade consists of one or more [Phases], each of which has one or more
-/// [Transformer]s that run in parallel, potentially on the same inputs. The
-/// inputs of the first phase are the source assets for this cascade's package.
-/// The inputs of each successive phase are the outputs of the previous phase,
-/// as well as any assets that haven't yet been transformed.
-class AssetCascade {
-  /// The name of the package whose assets are managed.
-  final String package;
-
-  /// The [PackageGraph] that tracks all [AssetCascade]s for all dependencies of
-  /// the current app.
-  final PackageGraph graph;
-
-  /// The controllers for the [AssetNode]s that provide information about this
-  /// cascade's package's source assets.
-  final _sourceControllerMap = new Map<AssetId, AssetNodeController>();
-
-  /// Futures for source assets that are currently being loaded.
-  ///
-  /// These futures are cancelable so that if an asset is updated after a load
-  /// has been kicked off, the previous load can be ignored in favor of a new
-  /// one.
-  final _loadingSources = new Map<AssetId, CancelableFuture<Asset>>();
-
-  /// The list of phases in this cascade.
-  ///
-  /// This will always contain at least one phase, and the first phase will
-  /// never have any transformers. This ensures that every transformer can
-  /// request inputs from a previous phase.
-  final _phases = <Phase>[];
-
-  /// The subscription to the [Phase.onStatusChange] stream of the last [Phase]
-  /// in [_phases].
-  StreamSubscription _phaseStatusSubscription;
-
-  /// A stream that emits any errors from the cascade or the transformers.
-  ///
-  /// This emits errors as they're detected. If an error occurs in one part of
-  /// the cascade, unrelated parts will continue building.
-  Stream<BarbackException> get errors => _errorsController.stream;
-  final _errorsController =
-      new StreamController<BarbackException>.broadcast(sync: true);
-
-  /// How far along [this] is in processing its assets.
-  NodeStatus get status {
-    // Just check the last phase, since it will check all the previous phases
-    // itself.
-    return _phases.last.status;
-  }
-
-  /// The streams exposed by this cascade.
-  final _streams = new NodeStreams();
-  Stream<LogEntry> get onLog => _streams.onLog;
-  Stream<NodeStatus> get onStatusChange => _streams.onStatusChange;
-  Stream<AssetNode> get onAsset => _streams.onAsset;
-
-  /// Returns all currently-available output assets from this cascade.
-  Future<AssetSet> get availableOutputs => new Future.value(new AssetSet.from(
-      _phases.last.availableOutputs.map((node) => node.asset)));
-
-  /// Creates a new [AssetCascade].
-  ///
-  /// It loads source assets within [package] using [provider].
-  AssetCascade(this.graph, this.package) {
-    _addPhase(new Phase(this, package));
-    _streams.onAssetPool.add(_phases.last.onAsset);
-  }
-
-  /// Gets the asset identified by [id].
-  ///
-  /// If [id] is for a generated or transformed asset, this will wait until it
-  /// has been created and return it. This means that the returned asset will
-  /// always be [AssetState.AVAILABLE].
-  ///
-  /// If the asset cannot be found, returns null.
-  Future<AssetNode> getAssetNode(AssetId id) {
-    assert(id.package == package);
-
-    var oldLastPhase = _phases.last;
-    // TODO(rnystrom): Waiting for the entire build to complete is unnecessary
-    // in some cases. Should optimize:
-    // * [id] may be generated before the compilation is finished. We should
-    //   be able to quickly check whether there are any more in-place
-    //   transformations that can be run on it. If not, we can return it early.
-    // * If [id] has never been generated and all active transformers provide
-    //   metadata about the file names of assets it can emit, we can prove that
-    //   none of them can emit [id] and fail early.
-    return oldLastPhase.getOutput(id).then((node) {
-      // The last phase may have changed if [updateSources] was called after
-      // requesting the output. In that case, we want the output from the new
-      // last phase.
-      if (_phases.last == oldLastPhase) return node;
-      return getAssetNode(id);
-    });
-  }
-
-  /// Adds [sources] to the graph's known set of source assets.
-  ///
-  /// Begins applying any transforms that can consume any of the sources. If a
-  /// given source is already known, it is considered modified and all
-  /// transforms that use it will be re-applied.
-  void updateSources(Iterable<AssetId> sources) {
-    for (var id in sources) {
-      var controller = _sourceControllerMap[id];
-      if (controller != null) {
-        controller.setDirty();
-      } else {
-        _sourceControllerMap[id] = new AssetNodeController(id);
-        _phases.first.addInput(_sourceControllerMap[id].node);
-      }
-
-      // If this source was already loading, cancel the old load, since it may
-      // return out-of-date contents for the asset.
-      if (_loadingSources.containsKey(id)) _loadingSources[id].cancel();
-
-      _loadingSources[id] = new CancelableFuture<Asset>(
-          syncFuture(() => graph.provider.getAsset(id)));
-      _loadingSources[id].whenComplete(() {
-        _loadingSources.remove(id);
-      }).then((asset) {
-        var controller = _sourceControllerMap[id].setAvailable(asset);
-      }).catchError((error, stack) {
-        reportError(new AssetLoadException(id, error, stack));
-
-        // TODO(nweiz): propagate error information through asset nodes.
-        _sourceControllerMap.remove(id).setRemoved();
-      });
-    }
-  }
-
-  /// Removes [removed] from the graph's known set of source assets.
-  void removeSources(Iterable<AssetId> removed) {
-    removed.forEach((id) {
-      // If the source was being loaded, cancel that load.
-      if (_loadingSources.containsKey(id)) _loadingSources.remove(id).cancel();
-
-      var controller = _sourceControllerMap.remove(id);
-      // Don't choke if an id is double-removed for some reason.
-      if (controller != null) controller.setRemoved();
-    });
-  }
-
-  /// Sets this cascade's transformer phases to [transformers].
-  ///
-  /// Elements of the inner iterable of [transformers] must be [Transformer]s,
-  /// [TransformerGroup]s, or [AggregateTransformer]s.
-  void updateTransformers(Iterable<Iterable> transformersIterable) {
-    _streams.onAssetPool.remove(_phases.last.onAsset);
-    var transformers = transformersIterable.toList();
-
-    // Always preserve a single phase with no transformers at the beginning of
-    // the cascade so that [TransformNode]s in the first populated phase will
-    // have something to request assets from.
-    for (var i = 0; i < transformers.length; i++) {
-      if (_phases.length > i + 1) {
-        _phases[i + 1].updateTransformers(transformers[i]);
-        continue;
-      }
-
-      var phase = _phases.last.addPhase();
-      _addPhase(phase);
-      phase.updateTransformers(transformers[i]);
-    }
-
-    for (var i = transformers.length + 1; i < _phases.length; i++) {
-      _phases[i].remove();
-    }
-    _phases.removeRange(transformers.length + 1, _phases.length);
-
-    _phaseStatusSubscription.cancel();
-    _phaseStatusSubscription = _phases.last.onStatusChange
-        .listen(_streams.changeStatus);
-
-    _streams.onAssetPool.add(_phases.last.onAsset);
-  }
-
-  /// Force all [LazyTransformer]s' transforms in this cascade to begin
-  /// producing concrete assets.
-  void forceAllTransforms() {
-    for (var phase in _phases) {
-      phase.forceAllTransforms();
-    }
-  }
-
-  void reportError(BarbackException error) {
-    _errorsController.add(error);
-  }
-
-  /// Add [phase] to the end of [_phases] and watch its streams.
-  void _addPhase(Phase phase) {
-    _streams.onLogPool.add(phase.onLog);
-    if (_phaseStatusSubscription != null) _phaseStatusSubscription.cancel();
-    _phaseStatusSubscription =
-        phase.onStatusChange.listen(_streams.changeStatus);
-
-    _phases.add(phase);
-  }
-
-  String toString() => "cascade for $package";
-}