added a timeout of 500 milliseconds.

client/lib/search.dart

Index: client/lib/search.dart
diff --git a/client/lib/search.dart b/client/lib/search.dart
index dd300dde9a7802f24826c3d49ec955d2c6ba1246..08bf642fbd4f753689ed6e4fda01490d50cb7fe5 100644
--- a/client/lib/search.dart
+++ b/client/lib/search.dart
@@ -10,9 +10,15 @@
  */
 library search;
 
+import 'dart:async';
+import 'package:web_ui/web_ui.dart';
+
 /** Search Index */
 Map<String, String> index = {};
 
+/** Search query. */
+@observable String searchQuery = "";
+
 class SearchResult implements Comparable {
 
   /** Qualified name of this search result references. */
@@ -55,15 +61,22 @@ Map<String, int> value = {
  * A score is given to each potential search result based off how likely it is
  * the appropriate qualified name to return for the search query. 
  */
-List<SearchResult> lookupSearchResults(String searchQuery, int maxResults) {
-
+List<SearchResult> lookupSearchResults(String query, int maxResults) {  
+  
+  var stopwatch = new Stopwatch()..start();
+  
   var scoredResults = <SearchResult>[];
   var resultSet = new Set<String>();
-  var queryList = searchQuery.trim().toLowerCase().split(' ');
+  var queryList = query.trim().toLowerCase().split(' ');
   queryList.forEach((q) => resultSet.addAll(index.keys.where((e) =>
     e.toLowerCase().contains(q))));
   
-  for (var r in resultSet) {
+  for (var r in resultSet) {    
+    /// If it is taking too long to compute the search results, time out and
+    /// return an empty list of results.
+    if (stopwatch.elapsedMilliseconds > 500) {
+      return [];
+    }
     int score = 0;
     var lowerCaseResult = r.toLowerCase();
     var type = index[r];
@@ -123,6 +136,11 @@ List<SearchResult> lookupSearchResults(String searchQuery, int maxResults) {
     scoredResults.add(new SearchResult(r, type, score));
   }
   
+  /// If it is taking too long to compute the search results, time out and
+  /// return an empty list of results.
+  if (stopwatch.elapsedMilliseconds > 500) {
+    return [];
+  }
   scoredResults.sort();
   updatePositions(scoredResults);
   if (scoredResults.length > maxResults) {
@@ -136,4 +154,4 @@ void updatePositions(List<SearchResult> list) {
   for(int i = 0; i < list.length; i++) {
     list[i].position = i;
   }
-}
+}