From e5a07dae467f17745ceabd2c5ebe45cba7efe1ae Mon Sep 17 00:00:00 2001
From: Ben Turner <bent.mozilla@gmail.com>
Date: Wed, 4 Aug 2010 14:44:28 -0700
Subject: [PATCH] Bug 583923 - 'IndexedDB: Don't fire events if there are no
 listeners for it'. r=sicking.

---
 dom/indexedDB/AsyncConnectionHelper.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/dom/indexedDB/AsyncConnectionHelper.cpp b/dom/indexedDB/AsyncConnectionHelper.cpp
index a5ffe30dd4b1..c76233c91839 100644
--- a/dom/indexedDB/AsyncConnectionHelper.cpp
+++ b/dom/indexedDB/AsyncConnectionHelper.cpp
@@ -313,6 +313,17 @@ AsyncConnectionHelper::OnSuccess(nsIDOMEventTarget* aTarget)
     return result;
   }
 
+  // Check to make sure we have a listener here before actually firing.
+  nsCOMPtr<nsPIDOMEventTarget> target(do_QueryInterface(aTarget));
+  if (target) {
+    nsIEventListenerManager* manager = target->GetListenerManager(PR_FALSE);
+    if (!manager ||
+        !manager->HasListenersFor(NS_LITERAL_STRING(SUCCESS_EVT_STR))) {
+      // No listeners here, skip creating and dispatching the event.
+      return OK;
+    }
+  }
+
   if (NS_FAILED(variant->SetWritable(PR_FALSE))) {
     NS_ERROR("Failed to make variant readonly!");
     return nsIIDBDatabaseException::UNKNOWN_ERR;