Expand barback's notion of dirtiness to understand declaredness.

pkg/barback/lib/src/phase.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;
 
 import 'dart:async';
 
 import 'asset_cascade.dart';
 import 'asset_id.dart';
 import 'asset_node.dart';
 import 'errors.dart';
 import 'group_runner.dart';
 import 'log.dart';
 import 'multiset.dart';
+import 'node_status.dart';
 import 'node_streams.dart';
 import 'phase_forwarder.dart';
 import 'phase_input.dart';
 import 'phase_output.dart';
 import 'transformer.dart';
 import 'transformer_group.dart';
 import 'utils.dart';
 
 /// One phase in the ordered series of transformations in an [AssetCascade].
 ///
@@ skipping 47 matching lines @@
   /// group, and so shouldn't be forwarded through the phase as a whole.
   ///
   /// In order to detect whether an output has been forwarded through a group or
   /// a PhaseInput, we must be able to distinguish it from other outputs with
   /// the same id. To do so, we check if its origin is in [_inputOrigins]. If
   /// so, it's been forwarded unmodified.
   final _inputOrigins = new Multiset<AssetNode>();
 
   /// The streams exposed by this phase.
   final _streams = new NodeStreams();
-  Stream get onDone => _streams.onDone;
+  Stream<NodeStatus> 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.
-  ///
-  /// A phase is considered dirty if any of the previous phases in the same
-  /// cascade are dirty, since those phases could emit an asset that this phase
-  /// will then need to process.
-  bool get isDirty => (previous != null && previous.isDirty) ||
-      _inputs.values.any((input) => input.isDirty) ||
-      _groups.values.any((group) => group.isDirty);
+  /// How far along [this] is in processing its assets.
+  NodeStatus get status {
+    var inputStatus = NodeStatus.dirtiest(
+        _inputs.values.map((input) => input.status));
+    var groupStatus = NodeStatus.dirtiest(
+        _groups.values.map((group) => group.status));
+    return (previous == null ? NodeStatus.IDLE : previous.status)
+        .dirtier(inputStatus)
+        .dirtier(groupStatus);
+  }
 
   /// The previous phase in the cascade, or null if this is the first phase.
   final Phase previous;
 
-  /// The subscription to [previous]'s [onDone] stream.
-  StreamSubscription _previousOnDoneSubscription;
+  /// The subscription to [previous]'s [onStatusChange] stream.
+  StreamSubscription _previousStatusSubscription;
 
   /// The subscription to [previous]'s [onAsset] stream.
   StreamSubscription<AssetNode> _previousOnAssetSubscription;
 
   /// A map of asset ids to completers for [getInput] requests.
   ///
   /// If an asset node is requested before it's available, we put a completer in
   /// this map to wait for the asset to be generated. If it's not generated, the
   /// completer should complete to `null`.
   final _pendingOutputRequests = new Map<AssetId, Completer<AssetNode>>();
 
   /// Returns all currently-available output assets for this phase.
   Set<AssetNode> get availableOutputs {
     return _outputs.values
         .map((output) => output.output)
         .where((node) => node.state.isAvailable)
         .toSet();
   }
 
   // TODO(nweiz): Rather than passing the cascade and the phase everywhere,
   // create an interface that just exposes [getInput]. Emit errors via
   // [AssetNode]s.
   Phase(AssetCascade cascade, String location)
       : this._(cascade, location, 0);
 
   Phase._(this.cascade, this._location, this._index, [this.previous]) {
     if (previous != null) {
       _previousOnAssetSubscription = previous.onAsset.listen(addInput);
-      _previousOnDoneSubscription = previous.onDone.listen((_) {
-        if (!isDirty) _streams.onDoneController.add(null);
-      });
+      _previousStatusSubscription = previous.onStatusChange
+          .listen((_) => _streams.changeStatus(status));
     }
 
-    onDone.listen((_) {
-      // All the previous phases have finished building. If anyone's still
-      // waiting for outputs, cut off the wait; we won't be generating them,
-      // at least until a source asset changes.
+    onStatusChange.listen((status) {
+      if (status == NodeStatus.RUNNING) return;
+
+      // All the previous phases have finished declaring or producing their
+      // outputs. If anyone's still waiting for outputs, cut off the wait; we
+      // won't be generating them, at least until a source asset changes.
       for (var completer in _pendingOutputRequests.values) {
         completer.complete(null);
       }
       _pendingOutputRequests.clear();
     });
   }
 
   /// Adds a new asset as an input for this phase.
   ///
   /// [node] doesn't have to be [AssetState.AVAILABLE]. Once it is, the phase
@@ skipping 17 matching lines @@
       _handleOutputWithoutForwarder(forwarder.output);
     }
 
     _inputOrigins.add(node.origin);
     var input = new PhaseInput(this, node, "$_location.$_index");
     _inputs[node.id] = input;
     input.input.whenRemoved(() {
       _inputOrigins.remove(node.origin);
       _inputs.remove(node.id);
       _forwarders.remove(node.id).remove();
-      if (!isDirty) _streams.onDoneController.add(null);
+      _streams.changeStatus(status);
     });
     input.onAsset.listen(_handleOutput);
     _streams.onLogPool.add(input.onLog);
-    input.onDone.listen((_) {
-      if (!isDirty) _streams.onDoneController.add(null);
-    });
+    input.onStatusChange.listen((_) => _streams.changeStatus(status));
 
     input.updateTransformers(_transformers);
 
     for (var group in _groups.values) {
       group.addInput(node);
     }
   }
 
   // TODO(nweiz): If the output is available when this is called, it's
   // theoretically possible for it to become unavailable between the call and
@@ skipping 20 matching lines @@
         // try again, since it could be generated again.
         output.force();
         return output.whenAvailable((_) {
           return output;
         }).catchError((error) {
           if (error is! AssetNotFoundException) throw error;
           return getOutput(id);
         });
       }
 
-      // If neither this phase nor the previous phases are dirty, the requested
-      // output won't be generated and we can safely return null.
-      if (!isDirty) return null;
+      // If this phase and the previous phases are fully declared or done, the
+      // requested output won't be generated and we can safely return null.
+      if (status != NodeStatus.RUNNING) return null;
 
       // Otherwise, store a completer for the asset node. If it's generated in
       // the future, we'll complete this completer.
       var completer = _pendingOutputRequests.putIfAbsent(id,
           () => new Completer.sync());
       return completer.future;
     });
   }
 
   /// Set this phase's transformers to [transformers].
@@ skipping 10 matching lines @@
     var oldGroups = _groups.keys.toSet();
     for (var removed in oldGroups.difference(newGroups)) {
       _groups.remove(removed).remove();
     }
 
     for (var added in newGroups.difference(oldGroups)) {
       var runner = new GroupRunner(cascade, added, "$_location.$_index");
       _groups[added] = runner;
       runner.onAsset.listen(_handleOutput);
       _streams.onLogPool.add(runner.onLog);
-      runner.onDone.listen((_) {
-        if (!isDirty) _streams.onDoneController.add(null);
-      });
+      runner.onStatusChange.listen((_) => _streams.changeStatus(status));
       for (var input in _inputs.values) {
         runner.addInput(input.input);
       }
     }
 
     for (var forwarder in _forwarders.values) {
       forwarder.updateTransformers(_transformers.length, _groups.length);
     }
   }
 
@@ skipping 27 matching lines @@
   ///
   /// This will remove all the phase's outputs.
   void remove() {
     for (var input in _inputs.values.toList()) {
       input.remove();
     }
     for (var group in _groups.values) {
       group.remove();
     }
     _streams.close();
-    if (_previousOnDoneSubscription != null) {
-      _previousOnDoneSubscription.cancel();
+    if (_previousStatusSubscription != null) {
+      _previousStatusSubscription.cancel();
     }
     if (_previousOnAssetSubscription != null) {
       _previousOnAssetSubscription.cancel();
     }
   }
 
   /// Add [asset] as an output of this phase.
   void _handleOutput(AssetNode asset) {
     if (_inputOrigins.contains(asset.origin)) {
       _forwarders[asset.id].addIntermediateAsset(asset);
@@ skipping 43 matching lines @@
     assert(asset.state.isDirty);
     asset.force();
     asset.whenStateChanges().then((state) {
       if (state.isRemoved) return getOutput(asset.id);
       return asset;
     }).then(request.complete).catchError(request.completeError);
   }
 
   String toString() => "phase $_location.$_index";
 }