1646054 - Remove TaskQueue::EventTargetWrapper

Status: RESOLVED FIXED

(Core :: XPCOM, task)

Description

[Jean-Yves Avenard [:jya]]

TaskQueue is already a nsISerialEventTarget ; there's no need to wrap it in another nsISerialEventTarget.

I can't really tell what was behind the TaskQueue::EventTargetWrapper in the first place; other than preserving the nsIEventTarget::Dispatch's flags.

But that can be easily achieved without the need of a wrapper.

Comment 1

[Jean-Yves Avenard [:jya]]

In bug 1602167; work was done to preserve the dispatch flags in the TaskQueue ;

however this would have had no effect as TaskQueue doesn't override the AbstractThread::Dispatch(already_AddRefed<nsIRunnable> event, uint32_t flags) method which will always drop the flags before calling Dispatch(already_AddRefed<nsIRunnable> aRunnable, DispatchReason aReason) [1]

[1] https://searchfox.org/mozilla-central/rev/027893497316897b8f292bde48dbb6da2391a331/xpcom/threads/AbstractThread.cpp#236-240

The EventTargetWrapper would have properly preserved the flags, so we can simply move that Dispatch method in the taskqueue instead while we're at it.

Comment 2

[Jean-Yves Avenard [:jya]]

Attachment: Bug 1646054 - P1. Remove EventTargetWrapper class. r?froydnj

We also establish the intent of bug 1602167 on the TaskQueue object

Comment 3

[Jean-Yves Avenard [:jya]]

Attachment: Bug 1646054 - P2. Always retain dispatch flags r?froydnj

When TaskQueue was first conceived; it was only used with AbstractThreads and with tail dispatch.
By default, AbstractThread::Dispatch dropped the flags , as it was dispatching all tasks via the tail dispatcher.

It was an oversight, there's no use-case where we wouldn't want the dispatch flags to be carried forward.

It also simplifies the code and TaskQueue's use.

Depends on D80351

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ad3e3c470aec
P1. Remove EventTargetWrapper class. r=froydnj
https://hg.mozilla.org/integration/autoland/rev/d8c9e055d410
P2. Always retain dispatch flags r=froydnj

Comment 5

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/ad3e3c470aec
https://hg.mozilla.org/mozilla-central/rev/d8c9e055d410