504727 - Create an already_Transferred helper for nsAutoPtr

Status: RESOLVED WONTFIX

(Core :: XPCOM, defect)

Description

[Boris Zbarsky [:bzbarsky]]

Attachment: Like so

Just a way to annotate return values that the callee should own and delete.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Attachment: Without the bogus assert

Comment 2

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

I really don't like the name.  I think "already" isn't really appropriate in this case.  It's not a matter of when a reference count is being incremented, it's a matter of ownership being transferred.  (I think a good name for this class could probably be applied back to renaming already_AddRefed if we really wanted to, although I doubt it would be worth it.)

I've been trying to think if I can get a good name out of things like "caller owns" or "must free", but I'm not too happy with them either.

Comment 3

[Benjamin Smedberg]

Comment on attachment 389417 [details] [diff] [review]
Without the bogus assert

Is the goal to make the code more readable, or prevent some bad construct from happening at compile-time? I really don't think this makes it any more readable.

Comment 4

[Boris Zbarsky [:bzbarsky]]

The goal is to keep:

  nsFoo* foo = GetFoo();

from compiling and to make it clear to anyone reading the header that GetFoo() needs to be assigned into an nsAutoPtr.

Could call it caller_MustFree

Comment 5

[Benjamin Smedberg]

boost::scoped_ptr doesn't have a similar helper... I'm skeptical that the reward/confusion factor makes this worthwhile.

Comment 6

[Boris Zbarsky [:bzbarsky]]

I can live with wontfixing this; just would like us to make a call so I can land (or modify and land) the patches in bug 504221.

Comment 7

[Boris Zbarsky [:bzbarsky]]

OK, per ircdiscussion with Benjamin, wontfix.