IncrementalKernalGenerator watch source callback

pkg/front_end/lib/src/incremental_kernel_generator_impl.dart

 // Copyright (c) 2017, 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:async';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_resolution_map.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/error/error.dart';
@@ skipping 39 matching lines @@
 class IncrementalKernelGeneratorImpl implements IncrementalKernelGenerator {
   final IncrementalResolvedAstGenerator _resolvedAstGenerator;
   final ProcessedOptions _options;
 
   IncrementalKernelGeneratorImpl(Uri source, ProcessedOptions options)
       : _resolvedAstGenerator =
             new IncrementalResolvedAstGeneratorImpl(source, options),
         _options = options;
 
   @override
-  Future<DeltaProgram> computeDelta() async {
+  Future<DeltaProgram> computeDelta(
+      {Future<Null> watch(Uri uri, bool used)}) async {
     var deltaLibraries = await _resolvedAstGenerator.computeDelta();
     var kernelOptions = _convertOptions(_options);
     var packages = null; // TODO(paulberry)
     var kernels = <Uri, Program>{};
-    deltaLibraries.newState.forEach((uri, resolvedLibrary) {
+    for (Uri uri in deltaLibraries.newState.keys) {
       // The kernel generation code doesn't currently support building a kernel
       // directly from resolved ASTs--it wants to query an analysis context.  So
       // we provide it with a proxy analysis context that feeds it the resolved
       // ASTs.
       var strongMode = true; // TODO(paulberry): set this correctly
       var analysisOptions = new _AnalysisOptionsProxy(strongMode);
       var context =
           new _AnalysisContextProxy(deltaLibraries.newState, analysisOptions);
       var repository = new Repository();
       var loader =
           new DartLoader(repository, kernelOptions, packages, context: context);
       loader.loadLibrary(uri);
       kernels[uri] = new Program(repository.libraries);
-    });
+      // TODO(paulberry) rework watch invocation to eliminate race condition,
+      // include part source files, and prevent watch from being a bottleneck
+      if (watch != null) await watch(uri, true);
+    }
+    // TODO(paulberry) invoke watch with used=false for each unused source
     return new DeltaProgram(kernels);
   }
 
   @override
   void invalidate(String path) => _resolvedAstGenerator.invalidate(path);
 
   @override
   void invalidateAll() => _resolvedAstGenerator.invalidateAll();
 }
 
@@ skipping 48 matching lines @@
   Source forUri2(Uri absoluteUri) => new _SourceProxy(absoluteUri);
 
   noSuchMethod(Invocation invocation) => unimplemented();
 }
 
 class _SourceProxy extends BasicSource {
   _SourceProxy(Uri uri) : super(uri);
 
   noSuchMethod(Invocation invocation) => unimplemented();
 }