Flush results when contexts are made idle.

pkg/analyzer/lib/src/task/dart.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.task.dart;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 31 matching lines @@
 import 'package:analyzer/src/task/strong/checker.dart';
 import 'package:analyzer/src/task/strong_mode.dart';
 import 'package:analyzer/task/dart.dart';
 import 'package:analyzer/task/general.dart';
 import 'package:analyzer/task/model.dart';
 
 /**
  * The [ResultCachingPolicy] for ASTs.
  */
 const ResultCachingPolicy<CompilationUnit> AST_CACHING_POLICY =
-    const SimpleResultCachingPolicy(16384, 16384);
+    const SimpleResultCachingPolicy(16384, 32);
+
+/**
+ * The [ResultCachingPolicy] for fully resolved ASTs.  It is separated from
+ * [AST_CACHING_POLICY] because we want to keep some number of fully resolved
+ * ASTs when users switch between contexts, and they should not be pushed out
+ * of the cache by temporary partially resolved ASTs.
+ */
+const ResultCachingPolicy<CompilationUnit> AST_RESOLVED_CACHING_POLICY =
+    const SimpleResultCachingPolicy(1024, 32);
 
 /**
  * The [ResultCachingPolicy] for ASTs that can be reused when a library
  * on which the source depends is changed.  It is worth to keep some number
  * of these ASTs in memory in order to avoid parsing sources.  In contrast,
  * none of [AST_CACHING_POLICY] managed ASTs can be reused after a change, so
  * it is worth to keep them in memory while analysis is being performed, but
  * once analysis is done, they can be flushed.
  */
 const ResultCachingPolicy<CompilationUnit> AST_REUSABLE_CACHING_POLICY =
-    const SimpleResultCachingPolicy(1024, 1024);
+    const SimpleResultCachingPolicy(1024, 64);
 
 /**
  * The [ResultCachingPolicy] for lists of [ConstantEvaluationTarget]s.
  */
 const ResultCachingPolicy<List<ConstantEvaluationTarget>>
     CONSTANT_EVALUATION_TARGET_LIST_POLICY =
     const SimpleResultCachingPolicy(-1, -1);
 
 /**
  * The [ResultCachingPolicy] for [ConstantEvaluationTarget]s.
@@ skipping 6270 matching lines @@
 
   @override
   bool moveNext() {
     if (_newSources.isEmpty) {
       return false;
     }
     currentTarget = _newSources.removeLast();
     return true;
   }
 }