Last performed task diagnostics.

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 'dart:developer';
 
 import 'package:analyzer/src/generated/engine.dart' hide AnalysisTask;
@@ skipping 61 matching lines @@
 }
 
 /**
  * An object used to compute one or more analysis results associated with a
  * single target.
  *
  * Clients must extend this class when creating new tasks.
  */
 abstract class AnalysisTask {
   /**
+   * A queue storing the last 10 task descriptions for diagnostic purposes.
+   */
+  static final LimitedQueue<String> LAST_TASKS = new LimitedQueue<String>(10);
+
+  /**
    * A table mapping the types of analysis tasks to the number of times each
    * kind of task has been performed.
    */
   static final Map<Type, int> countMap = new HashMap<Type, int>();
 
   /**
    * A table mapping the types of analysis tasks to user tags used to collect
    * timing data for the Observatory.
    */
   static Map<Type, UserTag> tagMap = new HashMap<Type, UserTag>();
@@ skipping 167 matching lines @@
 
   /**
    * Perform this analysis task, ensuring that all exceptions are wrapped in an
    * [AnalysisException].
    *
    * Clients may not override this method.
    */
   void _safelyPerform() {
     try {
       //
+      // Store task description for diagnostics.
+      //
+      LAST_TASKS.add(description);
+
+      //
       // Report that this task is being performed.
       //
       String contextName = context.name;
       if (contextName == null) {
         contextName = 'unnamed';
       }
       AnalysisEngine.instance.instrumentationService
           .logAnalysisTask(contextName, this);
       //
       // Gather statistics on the performance of the task.
@@ skipping 446 matching lines @@
   /**
    * A work should be done, but without any special urgency.
    */
   NORMAL,
 
   /**
    * Nothing to do.
    */
   NONE
 }