Add BazelResultProvider for on-demand packages loading.

pkg/analyzer/lib/src/summary/bazel_summary.dart

 // Copyright (c) 2016, 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.
 
 import 'dart:convert';
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/utilities_collection.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
 import 'package:analyzer/src/summary/link.dart';
 import 'package:analyzer/src/summary/package_bundle_reader.dart';
 import 'package:analyzer/src/summary/summarize_elements.dart';
 import 'package:analyzer/src/util/fast_uri.dart';
 import 'package:convert/convert.dart';
 import 'package:crypto/crypto.dart';
 import 'package:meta/meta.dart';
 
 /**
  * Return the [Folder] where bundles for the given [absoluteUri] should be
  * looked for. This folder should contain corresponding `*.full.ds` files,
  * possibly more than one one.  Return `null` if the given [absoluteUri]
  * does not have the expected structure, so the output path cannot be computed.
  */
 typedef Folder GetOutputFolder(Uri absoluteUri);
 
 /**
+ * Load linked packages on demand from [SummaryProvider].
+ */
+class BazelResultProvider extends ResynthesizerResultProvider {
+  final SummaryDataStore dataStore;
+  final SummaryProvider summaryProvider;
+
+  final Map<Source, bool> sourceToSuccessMap = <Source, bool>{};
+  final Set<Package> addedPackages = new Set<Package>();
+
+  factory BazelResultProvider(SummaryProvider summaryProvider) {
+    SummaryDataStore dataStore = new SummaryDataStore(const <String>[]);
+    return new BazelResultProvider._(
+        summaryProvider.context, dataStore, summaryProvider);
+  }
+
+  BazelResultProvider._(InternalAnalysisContext context,

[Brian Wilkerson, 2016/09/29 21:54:07]

Should the context always be the same as the one in the summaryProvider? If so,
wouldn't it be better to access it here, rather than in the public constructor?

+      SummaryDataStore dataStore, this.summaryProvider)
+      : dataStore = dataStore,
+        super(context, dataStore) {
+    AnalysisContext sdkContext = context.sourceFactory.dartSdk.context;
+    createResynthesizer(sdkContext, sdkContext.typeProvider);
+  }
+
+  @override
+  bool hasResultsForSource(Source source) {
+    return sourceToSuccessMap.putIfAbsent(source, () {
+      List<Package> packages = summaryProvider.getLinkedPackages(source);
+      if (packages == null) {
+        return false;
+      }
+      for (Package package in packages) {
+        if (addedPackages.add(package)) {
+          dataStore.addBundle(null, package.unlinked);
+          dataStore.addBundle(null, package.linked);
+        }
+      }
+      String uriString = source.uri.toString();
+      return resynthesizer.hasLibrarySummary(uriString);
+    });
+  }
+}
+
+/**
  * Information about a Dart package in Bazel.
  */
 class Package {
   final File unlinkedFile;
   final PackageBundle unlinked;
   final Set<String> _unitUris = new Set<String>();
 
   PackageBundle _linked;
 
   Package(this.unlinkedFile, this.unlinked) {
@@ skipping 319 matching lines @@
       appendDependencies(this);
       if (transitiveDependencies.any((node) => node.failed)) {
         failed = true;
       }
     }
   }
 
   @override
   String toString() => package.toString();
 }