Improve barback/pub logging.

pkg/barback/lib/src/package_graph.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.package_graph;
 
 import 'dart:async';
 
 import 'asset_cascade.dart';
 import 'asset_id.dart';
 import 'asset_node.dart';
 import 'asset_set.dart';
+import 'barback_logger.dart';
 import 'build_result.dart';
 import 'errors.dart';
 import 'package_provider.dart';
 import 'transformer.dart';
 import 'utils.dart';
 
 /// The collection of [AssetCascade]s for an entire application.
 ///
 /// This tracks each package's [AssetCascade] and routes asset requests between
 /// them.
 class PackageGraph {
   /// The provider that exposes asset and package information.
   final PackageProvider provider;
 
+  /// The logger used to report transformer log entries. If this is null, then

[nweiz, 2013/10/16 19:41:27]

paragraph break

[Bob Nystrom, 2013/10/28 23:45:56]

Done.

+  /// [_defaultLogger] will be used instead.

[nweiz, 2013/10/16 19:41:27]

_defaultLogger isn't defined anywhere

[Bob Nystrom, 2013/10/28 23:45:56]

Done.

+  final BarbackLogger _logger;
+
   /// The [AssetCascade] for each package.
   final _cascades = <String, AssetCascade>{};
 
   /// The current [BuildResult] for each package's [AssetCascade].
   ///
   /// The result for a given package will be `null` if that [AssetCascade] is
   /// actively building.
   final _cascadeResults = <String, BuildResult>{};
 
   /// A stream that emits a [BuildResult] each time the build is completed,
@@ skipping 18 matching lines @@
   Stream<BarbackException> _errors;
 
   /// The most recent error emitted from a cascade's result stream.
   ///
   /// This is used to pipe an unexpected error from a build to the resulting
   /// [Future] returned by [getAllAssets].
   var _lastUnexpectedError;
 
   /// Creates a new [PackageGraph] that will transform assets in all packages
   /// made available by [provider].
-  PackageGraph(this.provider) {
+  PackageGraph(this.provider, {BarbackLogger logger})
+      : _logger = logger != null ? logger : new BarbackLogger() {
     for (var package in provider.packages) {
       var cascade = new AssetCascade(this, package);
       // The initial result for each cascade is "success" since the cascade
       // doesn't start building until some source in that graph is updated.
       _cascadeResults[package] = new BuildResult.success();
       _cascades[package] = cascade;
       cascade.onDirty.listen((_) {
         _cascadeResults[package] = null;
       });
 
+      cascade.onLog.listen(_logger.logEntry);
+
       cascade.results.listen((result) {
         _cascadeResults[cascade.package] = result;
         // If any cascade hasn't yet finished, the overall build isn't finished
         // either.
         if (_cascadeResults.values.any((result) => result == null)) return;
 
+        var errors = unionAll(
+            _cascadeResults.values.map((result) => result.errors));
+
+        var numLogErrors = _cascadeResults.values.fold(0,
+            (numErrors, result) => result.numErrors - result.errors.length);
+
         // Include all build errors for all cascades. If no cascades have
         // errors, the result will automatically be considered a success.
-        _resultsController.add(new BuildResult(unionAll(
-            _cascadeResults.values.map((result) => result.errors))));
+        _resultsController.add(new BuildResult(errors, numLogErrors));
       }, onError: (error) {
         _lastUnexpectedError = error;
         _resultsController.addError(error);
       });
     }
 
     _errors = mergeStreams(_cascades.values.map((cascade) => cascade.errors),
         broadcast: true);
   }
 
@@ skipping 62 matching lines @@
       if (cascade == null) throw new ArgumentError("Unknown package $package.");
       cascade.removeSources(ids);
     });
   }
 
   void updateTransformers(String package,
       Iterable<Iterable<Transformer>> transformers) {
     _cascades[package].updateTransformers(transformers);
   }
 }