Make Assets know their ID.

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.dart';
 import 'asset_graph.dart';
 import 'asset_id.dart';
 import 'asset_node.dart';
+import 'asset_set.dart';
 import 'errors.dart';
 import 'transform_node.dart';
 import 'transformer.dart';
 
 /// One phase in the ordered series of transformations in an [AssetGraph].
 ///
 /// 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.
@@ skipping 39 matching lines @@
   ///
   /// Outputs from this phase will be passed to it.
   final Phase _next;
 
   Phase(this.graph, this._index, this._transformers, this._next);
 
   /// Updates the phase's inputs with [updated] and removes [removed].
   ///
   /// This marks any affected [transforms] as dirty or discards them if their
   /// inputs are removed.
-  void updateInputs(Map<AssetId, Asset> updated, Set<AssetId> removed) {
+  void updateInputs(AssetSet updated, Set<AssetId> removed) {
     // Remove any nodes that are no longer being output. Handle removals first
     // in case there are assets that were removed by one transform but updated
     // by another. In that case, the update should win.
     for (var id in removed) {
       var node = inputs.remove(id);
 
       // Every transform that was using it is dirty now.
       if (node != null) {
         node.consumers.forEach((consumer) => consumer.dirty());
       }
     }
 
     // Update and new or modified assets.
-    updated.forEach((id, asset) {
-      var node = inputs.putIfAbsent(id, () => new AssetNode(id));
-
-      // If it's a new node, remember that so we can see if any new transforms
-      // will consume it.
-      if (node.asset == null) _newInputs.add(node);
-
-      node.updateAsset(asset);
-    });
+    for (var asset in updated) {
+      var node = inputs[asset.id];
+      if (node == null) {
+        // It's a new node. Add it and remember it so we can see if any new
+        // transforms will consume it.
+        node = new AssetNode(asset);
+        inputs[asset.id] = node;
+        _newInputs.add(node);
+      } else {
+        node.updateAsset(asset);
+      }
+    }
   }
 
   /// Processes this phase.
   ///
   /// For all new inputs, it tries to see if there are transformers that can
   /// consume them. Then all applicable transforms are applied.
   ///
   /// Returns a future that completes when processing is done. If there is
   /// nothing to process, returns `null`.
   Future process() {
     var future = _processNewInputs();
     if (future == null) {
       return _processTransforms();
     }
 
     return future.then((_) => _processTransforms());
   }
 
   /// Creates new transforms for any new inputs that are applicable.
   Future _processNewInputs() {
     if (_newInputs.isEmpty) return null;
 
     var futures = [];
     for (var node in _newInputs) {
       for (var transformer in _transformers) {
         // TODO(rnystrom): Catch all errors from isPrimary() and redirect
         // to results.
-        futures.add(transformer.isPrimary(node.id).then((isPrimary) {
+        futures.add(transformer.isPrimary(node.asset).then((isPrimary) {
           if (!isPrimary) return;
           var transform = new TransformNode(this, transformer, node);
           node.consumers.add(transform);
           _transforms.add(transform);
         }));
       }
     }
 
     _newInputs.clear();
 
     return Future.wait(futures);
   }
 
   /// Applies all currently wired up and dirty transforms.
   ///
   /// Passes their outputs to the next phase.
   Future _processTransforms() {
     var dirtyTransforms = _transforms.where((transform) => transform.isDirty);
     if (dirtyTransforms.isEmpty) return null;
 
     return Future.wait(dirtyTransforms.map((transform) => transform.apply()))
         .then((transformOutputs) {
       // Collect all of the outputs. Since the transforms are run in parallel,
       // we have to be careful here to ensure that the result is deterministic
       // and not influenced by the order that transforms complete.
-      var updated = new Map<AssetId, Asset>();
+      var updated = new AssetSet();
       var removed = new Set<AssetId>();
       var collisions = new Set<AssetId>();
 
       // Handle the generated outputs of all transforms first.
       for (var outputs in transformOutputs) {
         // Collect the outputs of all transformers together.
-        outputs.updated.forEach((id, asset) {
-          if (updated.containsKey(id)) {
+        for (var asset in outputs.updated) {
+          if (updated.containsId(asset.id)) {
             // Report a collision.
-            collisions.add(id);
+            collisions.add(asset.id);
           } else {
             // TODO(rnystrom): In the case of a collision, the asset that
             // "wins" is chosen non-deterministically. Do something better.
-            updated[id] = asset;
+            updated.add(asset);
           }
-        });
+        }
 
         // Track any assets no longer output by this transform. We don't
         // handle the case where *another* transform generates the asset
         // no longer generated by this one. updateInputs() handles that.
         removed.addAll(outputs.removed);
       }
 
       // Report any collisions in deterministic order.
       collisions = collisions.toList();
       collisions.sort((a, b) => a.toString().compareTo(b.toString()));
       for (var collision in collisions) {
         graph.reportError(new AssetCollisionException(collision));
         // TODO(rnystrom): Define what happens after a collision occurs.
       }
 
       // Pass the outputs to the next phase.
       _next.updateInputs(updated, removed);
     });
   }
 }