Issue 26044. Cache and use LibraryElementImpl.exportNamespace.

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:async';
 import 'dart:collection';
 
 import 'package:analyzer/src/dart/element/element.dart'
@@ skipping 547 matching lines @@
     // Stop if already validated.
     if (delta != null) {
       if (thisData.invalidateId == id) {
         return;
       }
       thisData.invalidateId = id;
     }
     // Ask the delta to validate.
     DeltaResult deltaResult = null;
     if (delta != null) {
-      deltaResult = delta.validate(_partition.context, target, descriptor);
+      deltaResult = delta.validate(_partition.context, target, descriptor,
+          thisData.state, thisData.value);
       if (deltaResult == DeltaResult.STOP) {
         return;
       }
     }
     if (deltaResult == DeltaResult.INVALIDATE_NO_DELTA) {
       delta = null;
     }
     if (deltaResult == null ||
         deltaResult == DeltaResult.INVALIDATE ||
         deltaResult == DeltaResult.INVALIDATE_NO_DELTA) {
@@ skipping 470 matching lines @@
 /**
  * The description for a change.
  */
 class Delta {
   final Source source;
 
   Delta(this.source);
 
   /**
    * Check whether this delta affects the result described by the given
-   * [descriptor] and [target].
+   * [descriptor] and [target]. The current [state] and [value] of the result
+   * are provided.
    */
   DeltaResult validate(InternalAnalysisContext context, AnalysisTarget target,
-      ResultDescriptor descriptor) {
+      ResultDescriptor descriptor, CacheState state, Object value) {

[Brian Wilkerson, 2016/03/20 21:26:29]

I'm not seeing where the state is used, but maybe I'm just missing something.

[scheglov, 2016/03/20 22:16:46]

No, you're not missing.
I thought that maybe it would be useful to provide it when we provide value, but
given that this is not API we can add it later if we would need it.

     return DeltaResult.INVALIDATE;
   }
 }
 
 /**
  * The possible results of validating analysis results against a [Delta].
  */
 enum DeltaResult {
   /**
    * Invalidate this result and continue visiting dependent results
@@ skipping 196 matching lines @@
   void resultAccessed(TargetedResult result) {}
 
   @override
   List<TargetedResult> resultStored(TargetedResult newResult, newValue) {
     return TargetedResult.EMPTY_LIST;
   }
 
   @override
   void targetRemoved(AnalysisTarget target) {}
 }