952660 - Simplify control flow in nsXPCWrappedJS::GetNewOrUsed

Status: RESOLVED FIXED

(Core :: XPConnect, defect)

Description

[Andrew McCreight [:mccr8]]

Lot of gotos in there.

Comment 1

[Andrew McCreight [:mccr8]]

Attachment: part 1 - Use smart pointer for clazz in nsXPCWrappedJS::GetNewOrUsed.

try run: https://tbpl.mozilla.org/?tree=Try&rev=20caa5300e5e

The trickiest thing the goto in GetNewOrUsed does is release clazz in some cases,
so using a smart pointer will simplify things.

Comment 2

[Andrew McCreight [:mccr8]]

Attachment: part 2 - Take advantage of new being infallible in nsXPCWrappedJS::GetNewOrUsed.

Comment 3

[Andrew McCreight [:mccr8]]

Attachment: part 3 - Eliminate goto return_wrapper.

Substitute in the tail of the function for each goto, then eliminate
the resulting branches where possible.

Comment 4

[Andrew McCreight [:mccr8]]

Attachment: part 4 - Eliminate now-unnecessary null check in nsXPCWrappedJS::GetNewOrUsed.

Comment 5

[Andrew McCreight [:mccr8]]

Attachment: part 5 - The null check at the end of nsXPCWrappedJS::GetNewOrUsed will always fail.

Comment 6

[Andrew McCreight [:mccr8]]

Attachment: part 6 - Add and use nsXPCWrappedJS::FindOrFindInherited.

FindInherited is only ever used after running Find, and the way the checks
are chained is a little weird.

Comment 7

[Andrew McCreight [:mccr8]]

Attachment: part 7 - Replace if with else in nsXPCWrappedJS::GetNewOrUsed.

We check for root, then don't change root and check for !root, so this can just be
an else.

Comment 8

[Andrew McCreight [:mccr8]]

Attachment: part 8 - Insert non-root wrappers into the list in the constructor for nsXPCWrappedJS.

A non-root wrapper has to be inserted into the list. There's only one place this is needed, but I
think it makes more sense like this.

Comment 9

[Bobby Holley (:bholley)]

Comment on attachment 8351197 [details] [diff] [review]
part 1 - Use smart pointer for clazz in nsXPCWrappedJS::GetNewOrUsed.

Could you rename clazz to clasp while you're at it? Doing it in a followup patch is fine.

Comment 10

[Bobby Holley (:bholley)]

Comment on attachment 8351204 [details] [diff] [review]
part 8 - Insert non-root wrappers into the list in the constructor for nsXPCWrappedJS.

Review of attachment 8351204 [details] [diff] [review]:
-----------------------------------------------------------------

Nice.

Comment 11

[Andrew McCreight [:mccr8]]

Thanks for the reviews!

https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?changeset=bd14c8ecd480

I added the clazz -> clasp rename as part 9: https://hg.mozilla.org/integration/mozilla-inbound/rev/bd14c8ecd480

Comment 12

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

https://hg.mozilla.org/mozilla-central/rev/22d4298df5ce
https://hg.mozilla.org/mozilla-central/rev/ac58b9be41b1
https://hg.mozilla.org/mozilla-central/rev/38dcdb7bef22
https://hg.mozilla.org/mozilla-central/rev/aaed859bdda9
https://hg.mozilla.org/mozilla-central/rev/c2d39db1260a
https://hg.mozilla.org/mozilla-central/rev/d58e0d23b28e
https://hg.mozilla.org/mozilla-central/rev/a6163494c298
https://hg.mozilla.org/mozilla-central/rev/9f773778b44f
https://hg.mozilla.org/mozilla-central/rev/bd14c8ecd480