1412189 - Avoid main-thread access in PrioritizedEventQueue::SelectQueue

Status: RESOLVED FIXED

(Core :: XPCOM, enhancement)

Description

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

Attachment: patch

This is basically a re-do of bug 1398417. I realized that SelectQueue is called by HasReadyEvent, which is supposed to work from any thread (not just the main thread). But SelectQueue calls GetInputHandlingStartTime, which calls nsRefreshDriver::GetNextTickHint, which is main-thread only.

So I decided that it would be better to take the other approach from bug 1398417: to avoid updating mInputHandlingStartTime from SelectQueue.

This does mean that GetEvent and will work slightly differently from HasReadyEvent. However, I can't think of any reason why that would actually be a problem.

Note that if all queues except the input queue are empty, we will still process input events even if mInputHandlingStartTime.IsNull():
http://searchfox.org/mozilla-central/rev/00fa5dacedb925022f53d025121f1a919508e7ce/xpcom/threads/PrioritizedEventQueue.cpp#168

Comment 1

[Ming-Chou Shih [:stone]]

Comment on attachment 8922627 [details] [diff] [review]
patch

Review of attachment 8922627 [details] [diff] [review]:
-----------------------------------------------------------------

LGTM, thanks.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/764e854bb9b3
Avoid main-thread access in PrioritizedEventQueue::SelectQueue (r=stone)

Comment 3

[Bogdan Tara[:bogdan_tara]]

https://hg.mozilla.org/mozilla-central/rev/764e854bb9b3