988787 - Should fire "handle-system-messages-done" at a correct time point

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Comment 1

[Gene Lian (I already quit Mozilla)]

Attachment: Patch

I noticed this bug when I'm trying to solve bug 874353. To be honest, I don't have a good solution to strip out "handle-system-messages-done" for now but I'm sure the way of firing it is wrong.

The reason is, imaging if we have two consecutive messages that need to be dispatched. When the first one is handled, the second one will be queued and returned by _dispatchMessage(). This will make the original notification fail:

  if (!dispatcher || !dispatcher.isHandling) {
    Services.obs.notifyObservers(/* aSubject */ null,
                                 "handle-system-messages-done",
                                 /* aData */ null);
  }

because |dispatcher.isHandling| is true. We should move it to a better time point to fire. Otherwise, the ContentChild/ContentParent will rely on the 30-second timeout to release the CPU wake lock, which is power consuming.

"handle-system-messages-done" has to be fired when the last message has been handled for sure.

Comment 2

[Gene Lian (I already quit Mozilla)]

Full try: https://tbpl.mozilla.org/?tree=Try&rev=1bc11ca3dbf4

Comment 3

[Gene Lian (I already quit Mozilla)]

Try looks good: https://tbpl.mozilla.org/?tree=Try&rev=e29c531e24e2

Comment 4

[Gene Lian (I already quit Mozilla)]

https://hg.mozilla.org/integration/b2g-inbound/rev/b8dc4e025d76

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/b8dc4e025d76