583923 - IndexedDB: Don't fire events if there are no listeners for it

Status: RESOLVED FIXED

(Core :: Storage: IndexedDB, defect)

Description

[Ben Turner (not reading bugmail, use the needinfo flag!)]

Attachment: Patch

We're wasting time firing events if no listener is attached. See patch.

Comment 1

[Olli Pettay [:smaug][[e-mail]]]

Comment on attachment 462270 [details] [diff] [review]
Patch

>diff --git a/dom/indexedDB/AsyncConnectionHelper.cpp b/dom/indexedDB/AsyncConnectionHelper.cpp
>--- a/dom/indexedDB/AsyncConnectionHelper.cpp
>+++ b/dom/indexedDB/AsyncConnectionHelper.cpp
>@@ -308,16 +308,27 @@ AsyncConnectionHelper::OnSuccess(nsIDOME
>     return nsIIDBDatabaseException::UNKNOWN_ERR;
>   }
> 
>   PRUint16 result = GetSuccessResult(variant);
>   if (result != OK) {
>     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))) {
This should be 
if (!manager || !manager->HasListenersFor(NS_LITERAL_STRING(SUCCESS_EVT_STR)) {
  ...
}

Because if you don't have any listeners, you may not have the manager at all.

Comment 2

[Ben Turner (not reading bugmail, use the needinfo flag!)]

Ah! Very nice. I'll change to that, thanks.

Comment 3

[Ben Turner (not reading bugmail, use the needinfo flag!)]

http://hg.mozilla.org/mozilla-central/rev/08084a1de4a1