Fix for 'analysis.getNavigation' implementation.

pkg/analysis_server/lib/src/domain_analysis.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 domain.analysis;
 
 import 'dart:async';
 import 'dart:core' hide Resource;
 
 import 'package:analysis_server/src/analysis_server.dart';
@@ skipping 94 matching lines @@
     // delay response
     return Response.DELAYED_RESPONSE;
   }
 
   /**
    * Implement the `analysis.getNavigation` request.
    */
   Response getNavigation(Request request) {
     var params = new AnalysisGetNavigationParams.fromRequest(request);
     String file = params.file;
-    int offset = params.offset;
-    Future<AnalysisDoneReason> completionFuture =
+    Future<AnalysisDoneReason> analysisFuture =
         server.onFileAnalysisComplete(file);
-    if (completionFuture == null) {
+    if (analysisFuture == null) {
       return new Response.getNavigationInvalidFile(request);
     }
-    completionFuture.then((AnalysisDoneReason reason) {
+    analysisFuture.then((AnalysisDoneReason reason) {
       switch (reason) {
         case AnalysisDoneReason.COMPLETE:
           List<CompilationUnit> units =
               server.getResolvedCompilationUnits(file);
           if (units.isEmpty) {
             server.sendResponse(new Response.getNavigationInvalidFile(request));
           } else {
             DartUnitNavigationComputer computer =
                 new DartUnitNavigationComputer();
+            _GetNavigationAstVisitor visitor = new _GetNavigationAstVisitor(
+                params.offset, params.offset + params.length, computer);
             for (CompilationUnit unit in units) {
-              AstNode node = new NodeLocator(offset).searchWithin(unit);
-              if (node != null) {
-                computer.compute(node);
-              }
+              unit.accept(visitor);
             }
             server.sendResponse(new AnalysisGetNavigationResult(
                     computer.files, computer.targets, computer.regions)
                 .toResponse(request.id));
           }
           break;
         case AnalysisDoneReason.CONTEXT_REMOVED:
           // The active contexts have changed, so try again.
           Response response = getNavigation(request);
           if (response != Response.DELAYED_RESPONSE) {
@@ skipping 139 matching lines @@
     }
     if (newOptions.generateLints != null) {
       updaters.add((engine.AnalysisOptionsImpl options) {
         options.lint = newOptions.generateLints;
       });
     }
     server.updateOptions(updaters);
     return new AnalysisUpdateOptionsResult().toResponse(request.id);
   }
 }
+
+/**
+ * An AST visitor that computer navigation regions in the givne region.
+ */
+class _GetNavigationAstVisitor extends UnifyingAstVisitor {
+  final int rangeStart;
+  final int rangeEnd;
+  final DartUnitNavigationComputer computer;
+
+  _GetNavigationAstVisitor(this.rangeStart, this.rangeEnd, this.computer);
+
+  bool isInRange(int offset) {
+    return rangeStart <= offset && offset <= rangeEnd;
+  }
+
+  @override
+  visitNode(AstNode node) {
+    // The node ends before the range starts.
+    if (node.end < rangeStart) {
+      return;
+    }
+    // The node starts after the range ends.
+    if (node.offset > rangeEnd) {
+      return;
+    }
+    // The node starts or ends in the range.
+    if (isInRange(node.offset) || isInRange(node.end)) {
+      computer.compute(node);
+      return;
+    }
+    super.visitNode(node);
+  }
+}