Remove PhaseInput and add TransformerSorter to barback.

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 'asset_node_set.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 'transformer_sorter.dart';
 import 'utils.dart';
 
 /// One phase in the ordered series of transformations in an [AssetCascade].
 ///
 /// Each phase can access outputs from previous phases and can in turn pass
 /// outputs to later phases. Phases are processed strictly serially. All
 /// transforms in a phase will be complete before moving on to the next phase.
 /// Within a single phase, all transforms will be run in parallel.
 ///
 /// Building can be interrupted between phases. For example, a source is added
 /// which starts the background process. Sometime during, say, phase 2 (which
 /// is running asynchronously) that source is modified. When the process queue
 /// goes to advance to phase 3, it will see that modification and start the
 /// waterfall from the beginning again.
 class Phase {
   /// The cascade that owns this phase.
   final AssetCascade cascade;
 
   /// A string describing the location of [this] in the transformer graph.
   final String _location;
 
   /// The index of [this] in its parent cascade or group.
   final int _index;
 
-  /// The transformers that can access [inputs].
-  ///
-  /// Their outputs will be available to the next phase.
-  final _transformers = new Set<Transformer>();
-
   /// The groups for this phase.
   final _groups = new Map<TransformerGroup, GroupRunner>();
 
   /// The inputs for this phase.
   ///
   /// For the first phase, these will be the source assets. For all other
   /// phases, they will be the outputs from the previous phase.
-  final _inputs = new Map<AssetId, PhaseInput>();
+  final _inputs = new AssetNodeSet();
+
+  /// The transformer sorters for this phase.
+  final _sorters = new Map<Transformer, TransformerSorter>();
 
   /// The forwarders for this phase.
   final _forwarders = new Map<AssetId, PhaseForwarder>();
 
   /// The outputs for this phase.
   final _outputs = new Map<AssetId, PhaseOutput>();
 
   /// The set of all [AssetNode.origin] properties of the input assets for this
   /// phase.
   ///
   /// This is used to determine which assets have been passed unmodified through
-  /// [_inputs] or [_groups]. Each input asset has a PhaseInput in [_inputs]. If
-  /// that input isn't consumed by any transformers, it will be forwarded
-  /// through the PhaseInput. However, it's possible that it was consumed by a
-  /// group, and so shouldn't be forwarded through the phase as a whole.
+  /// [_sorters] or [_groups]. It's possible that a given asset was consumed by
+  /// a group and not an individual transformer, 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.
+  /// a sorter, 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<NodeStatus> get onStatusChange => _streams.onStatusChange;
   Stream<AssetNode> get onAsset => _streams.onAsset;
   Stream<LogEntry> get onLog => _streams.onLog;
 
   /// How far along [this] is in processing its assets.
   NodeStatus get status {
-    var inputStatus = NodeStatus.dirtiest(
-        _inputs.values.map((input) => input.status));
+    // Before any transformers are added, the phase should be dirty if and only
+    // if any input is dirty.
+    if (_sorters.isEmpty && _groups.isEmpty) {
+      return _inputs.any((input) => input.state.isDirty) ?
+          NodeStatus.RUNNING : NodeStatus.IDLE;
+    }
+
+    var sorterStatus = NodeStatus.dirtiest(
+        _sorters.values.map((sorter) => sorter.status));
     var groupStatus = NodeStatus.dirtiest(
         _groups.values.map((group) => group.status));
     return (previous == null ? NodeStatus.IDLE : previous.status)
-        .dirtier(inputStatus)
+        .dirtier(sorterStatus)
         .dirtier(groupStatus);
   }
 
   /// The previous phase in the cascade, or null if this is the first phase.
   final Phase previous;
 
   /// The subscription to [previous]'s [onStatusChange] stream.
   StreamSubscription _previousStatusSubscription;
 
   /// The subscription to [previous]'s [onAsset] stream.
@@ skipping 44 matching lines @@
   ///
   /// [node] doesn't have to be [AssetState.AVAILABLE]. Once it is, the phase
   /// will automatically begin determining which transforms can consume it as a
   /// primary input. The transforms themselves won't be applied until [process]
   /// is called, however.
   ///
   /// This should only be used for brand-new assets or assets that have been
   /// removed and re-created. The phase will automatically handle updated assets
   /// using the [AssetNode.onStateChange] stream.
   void addInput(AssetNode node) {
-    if (_inputs.containsKey(node.id)) _inputs[node.id].remove();
-
     // Each group is one channel along which an asset may be forwarded, as is
     // each transformer.
-    var forwarder = new PhaseForwarder(
-        node, _transformers.length, _groups.length);
+    var forwarder = new PhaseForwarder(node, _sorters.length, _groups.length);
     _forwarders[node.id] = forwarder;
     forwarder.onAsset.listen(_handleOutputWithoutForwarder);
     if (forwarder.output != null) {
       _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();
+    _inputs.add(node);
+    node.onStateChange.listen((state) {
+      if (state.isRemoved) {
+        _inputOrigins.remove(node.origin);
+        _forwarders.remove(node.id).remove();
+      }
       _streams.changeStatus(status);
     });
-    input.onAsset.listen(_handleOutput);
-    _streams.onLogPool.add(input.onLog);
-    input.onStatusChange.listen((_) => _streams.changeStatus(status));
 
-    input.updateTransformers(_transformers);
-
+    for (var sorter in _sorters.values) {
+      sorter.addInput(node);
+    }
     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
   // the return. If it does so, it won't trigger the rebuilding process. To
   // avoid this, we should have this and the methods it calls take explicit
   // callbacks, as in [AssetNode.whenAvailable].
@@ skipping 31 matching lines @@
       // 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].
   void updateTransformers(Iterable transformers) {
-    var actualTransformers = transformers.where((op) => op is Transformer);
-    _transformers.clear();
-    _transformers.addAll(actualTransformers);
-    for (var input in _inputs.values) {
-      input.updateTransformers(actualTransformers);
+    var newTransformers = transformers.where((op) => op is Transformer)
+        .toSet();
+    var oldTransformers = _sorters.keys.toSet();
+    for (var removed in oldTransformers.difference(newTransformers)) {
+      _sorters.remove(removed).remove();
+    }
+
+    for (var transformer in newTransformers.difference(oldTransformers)) {
+      var sorter = new TransformerSorter(
+          this, transformer, "$_location.$_index");
+      _sorters[transformer] = sorter;
+      sorter.onAsset.listen(_handleOutput);
+      _streams.onLogPool.add(sorter.onLog);
+      sorter.onStatusChange.listen((_) => _streams.changeStatus(status));
+      for (var input in _inputs) {
+        sorter.addInput(input);
+      }
     }
 
     var newGroups = transformers.where((op) => op is TransformerGroup)
         .toSet();
     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.onStatusChange.listen((_) => _streams.changeStatus(status));
-      for (var input in _inputs.values) {
-        runner.addInput(input.input);
+      for (var input in _inputs) {
+        runner.addInput(input);
       }
     }
 
     for (var forwarder in _forwarders.values) {
-      forwarder.updateTransformers(_transformers.length, _groups.length);
+      forwarder.updateTransformers(_sorters.length, _groups.length);
     }
+
+    _streams.changeStatus(status);
   }
 
   /// Force all [LazyTransformer]s' transforms in this phase to begin producing
   /// concrete assets.
   void forceAllTransforms() {
+    for (var sorter in _sorters.values) {
+      sorter.forceAllTransforms();
+    }
+
     for (var group in _groups.values) {
       group.forceAllTransforms();
     }
-
-    for (var input in _inputs.values) {
-      input.forceAllTransforms();
-    }
   }
 
   /// Add a new phase after this one.
   ///
   /// This may only be called on a phase with no phase following it.
   Phase addPhase() {
     var next = new Phase._(cascade, _location, _index + 1, this);
     for (var output in _outputs.values.toList()) {
       // Remove [output]'s listeners because now they should get the asset from
       // [next], rather than this phase. Any transforms consuming [output] will
       // be re-run and will consume the output from the new final phase.
       output.removeListeners();
     }
     return next;
   }
 
   /// Mark this phase as removed.
   ///
   /// This will remove all the phase's outputs.
   void remove() {
-    for (var input in _inputs.values.toList()) {
-      input.remove();
+    for (var sorter in _sorters.values.toList()) {
+      sorter.remove();
     }
     for (var group in _groups.values) {
       group.remove();
     }
     _streams.close();
     if (_previousStatusSubscription != null) {
       _previousStatusSubscription.cancel();
     }
     if (_previousOnAssetSubscription != null) {
       _previousOnAssetSubscription.cancel();
@@ skipping 50 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";
 }