1253424 - small refactorings of nsTransactionStack

Status: RESOLVED FIXED

(Core :: DOM: Editor, defect)

Comment 1

[Nathan Froyd [:froydnj]]

Attachment: part 1 - add a already_AddRefed nsTransactionStack::Push overload

We unnecessarily refcount in several places when pushing items onto an
nsTransactionStack.  Adding an already_AddRefed overload will enable
avoid those unnecessary refcounts.

editor/ is currently unowned.  However, since these patches are small and
they're not touching core editor/ functionality, I don't feel bad about not
seeking Ehsan's input on them.  I think they can be reviewed by anybody who
understands Gecko code.

Comment 2

[Nathan Froyd [:froydnj]]

Attachment: part 2 - add nsTransactionStack::IsEmpty

Checking to see whether the stack is empty is a reasonably common
operation.  We can make the code clearer and more efficient (no need to
refcount to check the emptiness of the stack) in several cases.

Comment 3

[Eric Rahm [:erahm]]

Comment on attachment 8726415 [details] [diff] [review]
part 1 - add a already_AddRefed nsTransactionStack::Push overload

Review of attachment 8726415 [details] [diff] [review]:
-----------------------------------------------------------------

r=me Just a few small comments.

::: editor/txmgr/nsTransactionStack.cpp
@@ +25,5 @@
>  nsTransactionStack::Push(nsTransactionItem *aTransaction)
>  {
>    if (!aTransaction) {
>      return;
>    }

Can we get rid of this check?

@@ +41,5 @@
> +    return;
> +  }
> +
> +  // XXX we really want to use emplace_back here, but we don't have a
> +  // C++11 stdlib everywhere.

It might be worth noting why we use a dummy here -- to avoid the addref b/c an empty RefPtr won't addref when copied -- I know that because I'm reading the code but I could see it being confusing out of context.

Aside: push_back(Move(item)) would have worked if we could count on C++11 as well right?

Comment 4

[Eric Rahm [:erahm]]

Comment on attachment 8726416 [details] [diff] [review]
part 2 - add nsTransactionStack::IsEmpty

Review of attachment 8726416 [details] [diff] [review]:
-----------------------------------------------------------------

r=me

Comment 5

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/4c048ada6176
https://hg.mozilla.org/integration/mozilla-inbound/rev/4f323559171d

Comment 6

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/4c048ada6176
https://hg.mozilla.org/mozilla-central/rev/4f323559171d