Avoid race comditions in background completer.

1 files changed, 19 insertions, 13 deletions

diff --git a/pages/vomnibar.coffee b/pages/vomnibar.coffee
index b133b126..260b163f 100644
--- a/pages/vomnibar.coffee
+++ b/pages/vomnibar.coffee
@@ -206,28 +206,34 @@ class VomnibarUI
 # Sends filter and refresh requests to a Vomnibox completer on the background page.
 #
 class BackgroundCompleter
+  # We increment this counter on each message sent, and ignore responses which arrive too late.
+  @messageId: 0
+
   # - name: The background page completer that you want to interface with. Either "omni", "tabs", or
   # "bookmarks". */
   constructor: (@name) ->
     @filterPort = chrome.runtime.connect({ name: "filterCompleter" })
 
-  refresh: -> chrome.runtime.sendMessage({ handler: "refreshCompleter", name: @name })
+  refresh: ->
+    BackgroundCompleter.messageId += 1
+    chrome.runtime.sendMessage({ handler: "refreshCompleter", name: @name })
 
   filter: (query, callback) ->
-    id = Utils.createUniqueId()
+    id = BackgroundCompleter.messageId += 1
     @filterPort.onMessage.addListener (msg) =>
       @filterPort.onMessage.removeListener(arguments.callee)
-      # The result objects coming from the background page will be of the form:
-      #   { html: "", type: "", url: "" }
-      # type will be one of [tab, bookmark, history, domain].
-      results = msg.results.map (result) ->
-        functionToCall = if (result.type == "tab")
-          BackgroundCompleter.completionActions.switchToTab.curry(result.tabId)
-        else
-          BackgroundCompleter.completionActions.navigateToUrl.curry(result.url)
-        result.performAction = functionToCall
-        result
-      callback(results)
+      if id == BackgroundCompleter.messageId
+        # The result objects coming from the background page will be of the form:
+        #   { html: "", type: "", url: "" }
+        # type will be one of [tab, bookmark, history, domain].
+        results = msg.results.map (result) ->
+          functionToCall = if (result.type == "tab")
+            BackgroundCompleter.completionActions.switchToTab.curry(result.tabId)
+          else
+            BackgroundCompleter.completionActions.navigateToUrl.curry(result.url)
+          result.performAction = functionToCall
+          result
+        callback(results)
 
     @filterPort.postMessage({ id: id, name: @name, query: query })