Initial re-write of analysis context for the new task model

pkg/analyzer/lib/src/context/cache.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.src.context.cache;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/engine.dart'
@@ skipping 331 matching lines @@
 
   /**
    * Invalidate all of the information associated with this entry's target.
    */
   void invalidateAllInformation() {
     _resultMap.clear();
     _exception = null;
   }
 
   /**
+   * Return `true` if the state of the result represented by the given
+   * [descriptor] is [CacheState.INVALID].
+   */
+  bool isInvalid(ResultDescriptor descriptor) =>
+      getState(descriptor) == CacheState.INVALID;
+
+  /**
+   * Return `true` if the state of the result represented by the given
+   * [descriptor] is [CacheState.VALID].
+   */
+  bool isValid(ResultDescriptor descriptor) =>
+      getState(descriptor) == CacheState.VALID;
+
+  /**
    * Set the [CacheState.ERROR] state for given [descriptors], their values to
    * the corresponding default values, and remember the [exception] that caused
    * this state.
    */
   void setErrorState(
       CaughtException exception, List<ResultDescriptor> descriptors) {
     if (descriptors == null || descriptors.isEmpty) {
       throw new ArgumentError('at least one descriptor is expected');
     }
     if (exception == null) {
@@ skipping 394 matching lines @@
 // TODO(brianwilkerson) Consider making this a generic class so that the value
 // can be typed.
 class ResultData {
   /**
    * The state of the cached value.
    */
   CacheState state;
 
   /**
    * The value being cached, or the default value for the result if there is no
-   * value (for example, when the [state] is [CacheState.INVALID].
+   * value (for example, when the [state] is [CacheState.INVALID]).
    */
   Object value;
 
   /**
    * Initialize a newly created result holder to represent the value of data
    * described by the given [descriptor].
    */
   ResultData(ResultDescriptor descriptor) {
     state = CacheState.INVALID;
     value = descriptor.defaultValue;
@@ skipping 29 matching lines @@
    * structures in the cache, using the [retentionPolicy] to determine which
    * AST structures to flush.
    */
   UniversalCachePartition(InternalAnalysisContext context, int maxCacheSize,
       CacheRetentionPolicy retentionPolicy)
       : super(context, maxCacheSize, retentionPolicy);
 
   @override
   bool contains(AnalysisTarget target) => true;
 }