Add instrumentation (issue 22572)

pkg/analyzer/lib/task/model.dart

 // Copyright (c) 2015, 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 analyzer.task.model;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/generated/engine.dart' hide AnalysisTask;
 import 'package:analyzer/src/generated/java_engine.dart';
@@ skipping 152 matching lines @@
   String toString() => description;
 
   /**
    * Perform this analysis task, ensuring that all exceptions are wrapped in an
    * [AnalysisException].
    *
    * Clients should not override this method.
    */
   void _safelyPerform() {
     try {
+      //
+      // Report that this task is being performed.
+      //
+      String contextName = context.name;
+      if (contextName == null) {
+        contextName = 'unnamed';
+      }
+      AnalysisEngine.instance.instrumentationService.logAnalysisTask(
+          contextName,
+          description);
+      //
+      // Gather statistics on the performance of the task.
+      //
       int count = countMap[runtimeType];
       countMap[runtimeType] = count == null ? 1 : count + 1;
       Stopwatch stopwatch = stopwatchMap[runtimeType];
       if (stopwatch == null) {
         stopwatch = new Stopwatch();
         stopwatchMap[runtimeType] = stopwatch;
       }
       stopwatch.start();
+      //
+      // Actually perform the task.
+      //
       try {
         internalPerform();
       } finally {
         stopwatch.stop();
       }
     } on AnalysisException catch (exception) {
       rethrow;
     } catch (exception, stackTrace) {
       throw new AnalysisException(
           'Unexpected exception while performing $description',
@@ skipping 149 matching lines @@
    * be computed, or `false` if the inputs have been computed.
    *
    * It is safe to invoke [moveNext] after it has returned `false`. In this case
    * [moveNext] has no effect and will again return `false`.
    *
    * Throws a [StateError] if the value of the current result has not been
    * provided using [currentValue].
    */
   bool moveNext();
 }