Add an analysis option to disable cache flushing.

pkg/analyzer/lib/src/generated/engine.dart

 // Copyright (c) 2014, 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.generated.engine;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 1054 matching lines @@
    * kept in the cache.
    */
   int get cacheSize;
 
   /**
    * Return `true` if analysis is to generate dart2js related hint results.
    */
   bool get dart2jsHint;
 
   /**
+   * Return `true` if cache flushing should be disabled.  Setting this option to
+   * `true` can improve analysis speed at the expense of memory usage.  It may
+   * also be useful for working around bugs.
+   *
+   * This option should not be used when the analyzer is part of a long running
+   * process (such as the analysis server) because it has the potential to
+   * prevent memory from being reclaimed.
+   */
+  bool get disableCacheFlushing;
+
+  /**
    * Return `true` if the parser is to parse asserts in the initializer list of
    * a constructor.
    */
   bool get enableAssertInitializer;
 
   /**
    * Return `true` to enable custom assert messages (DEP 37).
    */
   bool get enableAssertMessage;
 
@@ skipping 213 matching lines @@
    * A flag indicating whether strong-mode inference hints should be
    * used.  This flag is not exposed in the interface, and should be
    * replaced by something more general.
    */
   // TODO(leafp): replace this with something more general
   bool strongModeHints = false;
 
   @override
   bool trackCacheDependencies = true;
 
+  @override
+  bool disableCacheFlushing = false;
+
   /**
    * A flag indicating whether implicit casts are allowed in [strongMode]
    * (they are always allowed in Dart 1.0 mode).
    *
    * This option is experimental and subject to change.
    */
   bool implicitCasts = true;
 
   /**
    * A list of non-nullable type names, prefixed by the library URI they belong
@@ skipping 46 matching lines @@
     lint = options.lint;
     preserveComments = options.preserveComments;
     strongMode = options.strongMode;
     if (options is AnalysisOptionsImpl) {
       strongModeHints = options.strongModeHints;
       implicitCasts = options.implicitCasts;
       nonnullableTypes = options.nonnullableTypes;
       implicitDynamic = options.implicitDynamic;
     }
     trackCacheDependencies = options.trackCacheDependencies;
+    disableCacheFlushing = options.disableCacheFlushing;
     finerGrainedInvalidation = options.finerGrainedInvalidation;
   }
 
   bool get analyzeFunctionBodies {
     if (identical(analyzeFunctionBodiesPredicate, _analyzeAllFunctionBodies)) {
       return true;
     } else if (identical(
         analyzeFunctionBodiesPredicate, _analyzeNoFunctionBodies)) {
       return false;
     } else {
@@ skipping 1287 matching lines @@
    * The data that was created from the source.
    */
   final E data;
 
   /**
    * Initialize a newly created holder to associate the given [data] with the
    * given [modificationTime].
    */
   TimestampedData(this.modificationTime, this.data);
 }