Use single map of Source to modification time.

pkg/analyzer/lib/src/dart/element/builder.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.dart.element.builder;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 56 matching lines @@
    * The analysis context within which directive elements are being built.
    */
   final AnalysisContext context;
 
   /**
    * The library element for which directive elements are being built.
    */
   final LibraryElementImpl libraryElement;
 
   /**
-   * Map from sources imported by this library to their modification times.
+   * Map from sources referenced by this library to their modification times.
    */
-  final Map<Source, int> importModificationTimeMap;
+  final Map<Source, int> sourceModificationTimeMap;
 
   /**
    * Map from sources imported by this library to their corresponding library
    * elements.
    */
   final Map<Source, LibraryElement> importLibraryMap;
 
   /**
    * Map from sources imported by this library to their corresponding source
    * kinds.
    */
   final Map<Source, SourceKind> importSourceKindMap;
 
   /**
-   * Map from sources exported by this library to their modification times.
-   */
-  final Map<Source, int> exportModificationTimeMap;
-
-  /**
    * Map from sources exported by this library to their corresponding library
    * elements.
    */
   final Map<Source, LibraryElement> exportLibraryMap;
 
   /**
    * Map from sources exported by this library to their corresponding source
    * kinds.
    */
   final Map<Source, SourceKind> exportSourceKindMap;
@@ skipping 20 matching lines @@
       new HashMap<String, PrefixElementImpl>();
 
   /**
    * Indicates whether an explicit import of `dart:core` has been found.
    */
   bool explicitlyImportsCore = false;
 
   DirectiveElementBuilder(
       this.context,
       this.libraryElement,
-      this.importModificationTimeMap,
+      this.sourceModificationTimeMap,
       this.importLibraryMap,
       this.importSourceKindMap,
-      this.exportModificationTimeMap,
       this.exportLibraryMap,
       this.exportSourceKindMap);
 
   @override
   Object visitCompilationUnit(CompilationUnit node) {
     //
     // Resolve directives.
     //
     for (Directive directive in node.directives) {
       directive.accept(this);
@@ skipping 15 matching lines @@
     libraryElement.imports = imports;
     libraryElement.exports = exports;
     return null;
   }
 
   @override
   Object visitExportDirective(ExportDirective node) {
     // Remove previous element. (It will remain null if the target is missing.)
     node.element = null;
     Source exportedSource = node.source;
-    int exportedTime = exportModificationTimeMap[exportedSource] ?? -1;
+    int exportedTime = sourceModificationTimeMap[exportedSource] ?? -1;
     if (exportedTime != -1) {
       // The exported source will be null if the URI in the export
       // directive was invalid.
       LibraryElement exportedLibrary = exportLibraryMap[exportedSource];
       if (exportedLibrary != null) {
         ExportElementImpl exportElement = new ExportElementImpl(node.offset);
         exportElement.metadata = _getElementAnnotations(node.metadata);
         StringLiteral uriLiteral = node.uri;
         if (uriLiteral != null) {
           exportElement.uriOffset = uriLiteral.offset;
@@ skipping 22 matching lines @@
       }
     }
     return null;
   }
 
   @override
   Object visitImportDirective(ImportDirective node) {
     // Remove previous element. (It will remain null if the target is missing.)
     node.element = null;
     Source importedSource = node.source;
-    int importedTime = importModificationTimeMap[importedSource] ?? -1;
+    int importedTime = sourceModificationTimeMap[importedSource] ?? -1;
     if (importedTime != -1) {
       // The imported source will be null if the URI in the import
       // directive was invalid.
       LibraryElement importedLibrary = importLibraryMap[importedSource];
       if (importedLibrary != null) {
         if (importedLibrary.isDartCore) {
           explicitlyImportsCore = true;
         }
         ImportElementImpl importElement = new ImportElementImpl(node.offset);
         importElement.metadata = _getElementAnnotations(node.metadata);
@@ skipping 1280 matching lines @@
     return null;
   }
 
   /**
    * Return the lexical identifiers associated with the given [identifiers].
    */
   static List<String> _getIdentifiers(NodeList<SimpleIdentifier> identifiers) {
     return identifiers.map((identifier) => identifier.name).toList();
   }
 }