Cache flushing implementation for the task model.

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 'package:analyzer/src/generated/engine.dart' hide AnalysisTask;
 import 'package:analyzer/src/generated/java_engine.dart';
@@ skipping 261 matching lines @@
  * [AnalysisTask].
  *
  * Clients are not expected to subtype this class.
  */
 abstract class ListResultDescriptor<E> implements ResultDescriptor<List<E>> {
   /**
    * Initialize a newly created analysis result to have the given [name]. If a
    * composite result is specified, then this result will contribute to it.
    */
   factory ListResultDescriptor(String name, List<E> defaultValue,
-      {CompositeResultDescriptor<List<E>> contributesTo}) = ListResultDescriptorImpl<E>;
+      {CompositeResultDescriptor<List<E>> contributesTo,
+      ResultCachingPolicy<List<E>> cachingPolicy}) = ListResultDescriptorImpl<E>;
 
   @override
   ListTaskInput<E> of(AnalysisTarget target);
 }
 
 /**
  * A description of an input to an [AnalysisTask] that can be used to compute
  * that input.
  *
  * Clients are not expected to subtype this class.
@@ skipping 38 matching lines @@
    * [V] must be a [List].
    * Return a task input that can be used to compute a list whose elements are
    * the result of passing keys [K] and the corresponding elements of [V] to
    * the [mapper] function.
    */
   TaskInput<List /*<E>*/ > toFlattenList(
       BinaryFunction<K, dynamic /*element of V*/, dynamic /*<E>*/ > mapper);
 }
 
 /**
+ * A policy object that can compute sizes of results and provide the maximum
+ * active and idle sizes that can be kept in the cache.
+ *
+ * All the [ResultDescriptor]s with the same [ResultCachingPolicy] instance
+ * share the same total size in a cache.
+ */
+abstract class ResultCachingPolicy<T> {
+  /**
+   * Return the maximum total size of results that can be kept in the cache
+   * while analysis is in progress.
+   */
+  int get maxActiveSize;
+
+  /**
+   * Return the maximum total size of results that can be kept in the cache
+   * while analysis is idle.
+   */
+  int get maxIdleSize;
+
+  /**
+   * Return the size of the given [object].
+   */
+  int measure(T object);
+}
+
+/**
  * A description of an analysis result that can be computed by an [AnalysisTask].
  *
  * Clients are not expected to subtype this class.
  */
 abstract class ResultDescriptor<V> {
   /**
    * Initialize a newly created analysis result to have the given [name]. If a
    * composite result is specified, then this result will contribute to it.
+   *
+   * The given [cachingPolicy] is used to limit the total size of results
+   * described by this descriptor. If no policy is specified, the results are
+   * never evicted from the cache, and removed only when they are invalidated.
    */
   factory ResultDescriptor(String name, V defaultValue,
-      {CompositeResultDescriptor<V> contributesTo}) = ResultDescriptorImpl;
+      {CompositeResultDescriptor<V> contributesTo,
+      ResultCachingPolicy<V> cachingPolicy}) = ResultDescriptorImpl;
+
+  /**
+   * Return the caching policy for results described by this descriptor.
+   */
+  ResultCachingPolicy<V> get cachingPolicy;
 
   /**
    * Return the default value for results described by this descriptor.
    */
   V get defaultValue;
 
   /**
    * Return the name of this descriptor.
    */
   String get name;
@@ skipping 106 matching lines @@
    * be computed, or `false` if the inputs have been computed.
    *
    * It is safe to invoke [moveNext] after it has returned `false`. In this case
    * [moveNext] has no effect and will again return `false`.
    *
    * Throws a [StateError] if the value of the current result has not been
    * provided using [currentValue].
    */
   bool moveNext();
 }