Expand barback's notion of dirtiness to understand declaredness.

pkg/barback/lib/src/phase_input.dart

 // 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.phase_input;
 
 import 'dart:async';
 
 import 'asset_forwarder.dart';
 import 'asset_node.dart';
 import 'log.dart';
+import 'node_status.dart';
 import 'node_streams.dart';
 import 'phase.dart';
 import 'transform_node.dart';
 import 'transformer.dart';
 
 /// A class for watching a single [AssetNode] and running any transforms that
 /// take that node as a primary input.
 class PhaseInput {
   /// The phase for which this is an input.
   final Phase _phase;
@@ skipping 14 matching lines @@
   final AssetForwarder _inputForwarder;
 
   /// The asset node for this input.
   AssetNode get input => _inputForwarder.node;
 
   /// The subscription to [input]'s [AssetNode.onStateChange] stream.
   StreamSubscription _inputSubscription;
 
   /// The streams exposed by this input.
   final _streams = new NodeStreams();
-  Stream get onDone => _streams.onDone;
+  Stream get onStatusChange => _streams.onStatusChange;
   Stream<AssetNode> get onAsset => _streams.onAsset;
   Stream<LogEntry> get onLog => _streams.onLog;
 
-  /// Whether [this] is dirty and still has more processing to do.
-  bool get isDirty => (input.state.isDirty && !input.deferred) ||
-      _transforms.any((transform) => transform.isDirty);
+  /// How far along [this] is in processing its assets.
+  NodeStatus get status {
+    var status = input.state.isDirty && !input.deferred ?
+        NodeStatus.MATERIALIZING : NodeStatus.IDLE;
+    return status.dirtier(NodeStatus.dirtiest(
+        _transforms.map((transform) => transform.status)));
+  }
 
   PhaseInput(this._phase, AssetNode input, this._location)
       : _inputForwarder = new AssetForwarder(input) {
     _inputSubscription = input.onStateChange.listen((state) {
       if (state.isRemoved) {
         remove();
-      } else if (state.isAvailable) {
-        if (!isDirty) _streams.onDoneController.add(null);
+      } else {
+        _streams.changeStatus(status);
       }
     });
   }
 
   /// Removes this input.
   ///
   /// This marks all outputs of the input as removed.
   void remove() {
     _streams.close();
     _inputSubscription.cancel();
     _inputForwarder.close();
   }
 
   /// Set this input's transformers to [transformers].
   void updateTransformers(Iterable<Transformer> newTransformersIterable) {
     var newTransformers = newTransformersIterable.toSet();
     for (var transform in _transforms.toList()) {
       if (newTransformers.remove(transform.transformer)) continue;
       transform.remove();
     }
 
     // The remaining [newTransformers] are those for which there are no
     // transforms in [_transforms].
     for (var transformer in newTransformers) {
       var transform = new TransformNode(
           _phase, transformer, input, _location);
       _transforms.add(transform);
 
-      transform.onDone.listen((_) {
-        if (!isDirty) _streams.onDoneController.add(null);
-      }, onDone: () => _transforms.remove(transform));
+      transform.onStatusChange.listen(
+          (_) => _streams.changeStatus(status),
+          onDone: () => _transforms.remove(transform));
 
       _streams.onAssetPool.add(transform.onAsset);
       _streams.onLogPool.add(transform.onLog);
     }
   }
 
   /// Force all [LazyTransformer]s' transforms in this input to begin producing
   /// concrete assets.
   void forceAllTransforms() {
     for (var transform in _transforms) {
       transform.force();
     }
   }
 
   String toString() => "phase input in $_location for $input";
 }