Cache flushing implementation for the task model.

pkg/analyzer/lib/src/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.src.task.model;
 
 import 'package:analyzer/src/generated/engine.dart' hide AnalysisTask;
 import 'package:analyzer/src/task/inputs.dart';
 import 'package:analyzer/task/model.dart';
 
 /**
+ * The default [ResultCachingPolicy], results are never flushed.
+ */
+const ResultCachingPolicy DEFAULT_CACHING_POLICY =
+    const SimpleResultCachingPolicy(-1, -1);
+
+/**
  * A concrete implementation of a [CompositeResultDescriptor].
  */
 class CompositeResultDescriptorImpl<V> extends ResultDescriptorImpl<V>
     implements CompositeResultDescriptor<V> {
   /**
    * The results that contribute to this result.
    */
   final List<ResultDescriptor<V>> contributors = <ResultDescriptor<V>>[];
 
   /**
@@ skipping 13 matching lines @@
  * A concrete implementation of a [ListResultDescriptor].
  */
 class ListResultDescriptorImpl<E> extends ResultDescriptorImpl<List<E>>
     implements ListResultDescriptor<E> {
   /**
    * Initialize a newly created analysis result to have the given [name] and
    * [defaultValue]. If a composite result is specified, then this result will
    * contribute to it.
    */
   ListResultDescriptorImpl(String name, List<E> defaultValue,
-      {CompositeResultDescriptor contributesTo})
-      : super(name, defaultValue, contributesTo: contributesTo);
+      {CompositeResultDescriptor contributesTo,
+      ResultCachingPolicy<List<E>> cachingPolicy: DEFAULT_CACHING_POLICY})
+      : super(name, defaultValue,
+          contributesTo: contributesTo, cachingPolicy: cachingPolicy);
 
   @override
   ListTaskInput<E> of(AnalysisTarget target) =>
       new ListTaskInputImpl<E>(target, this);
 }
 
 /**
  * A concrete implementation of a [ResultDescriptor].
  */
 class ResultDescriptorImpl<V> implements ResultDescriptor<V> {
   /**
    * The name of the result, used for debugging.
    */
   final String name;
 
   /**
    * Return the default value for results described by this descriptor.
    */
   final V defaultValue;
 
   /**
+   * The caching policy for results described by this descriptor.
+   */
+  final ResultCachingPolicy<V> cachingPolicy;
+
+  /**
    * Initialize a newly created analysis result to have the given [name] and
    * [defaultValue]. If a composite result is specified, then this result will
    * contribute to it.
    */
   ResultDescriptorImpl(this.name, this.defaultValue,
-      {CompositeResultDescriptor contributesTo}) {
+      {CompositeResultDescriptor contributesTo,
+      this.cachingPolicy: DEFAULT_CACHING_POLICY}) {
     if (contributesTo is CompositeResultDescriptorImpl) {
       contributesTo.recordContributor(this);
     }
   }
 
   @override
   TaskInput<V> of(AnalysisTarget target) =>
       new SimpleTaskInput<V>(target, this);
 
   @override
   String toString() => name;
 }
 
 /**
+ * A simple [ResultCachingPolicy] implementation that consider all the objects
+ * to be of the size `1`.
+ */
+class SimpleResultCachingPolicy<T> implements ResultCachingPolicy<T> {
+  @override
+  final int maxActiveSize;
+
+  @override
+  final int maxIdleSize;
+
+  const SimpleResultCachingPolicy(this.maxActiveSize, this.maxIdleSize);
+
+  @override
+  int measure(T object) => 1;
+}
+
+/**
  * A concrete implementation of a [TaskDescriptor].
  */
 class TaskDescriptorImpl implements TaskDescriptor {
   /**
    * The name of the described task, used for debugging.
    */
   final String name;
 
   /**
    * The function used to build the analysis task.
@@ skipping 26 matching lines @@
       Map<String, dynamic> inputs, Object inputMemento) {
     AnalysisTask task = buildTask(context, target);
     task.inputs = inputs;
     task.inputMemento = inputMemento;
     return task;
   }
 
   @override
   String toString() => name;
 }