480850 - (JS_New) JSAPI should support creating objects given a constructor Function

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement)

Description

[Jason Orendorff [:jorendorff]]

We've known this is a missing API for a long time now.

Because FUN_CLASP is for good reasons non-public, it's far from straightforward for JSAPI applications to implement this.  (I don't know that it's even possible without eval/JS_EvaluateScript.)

Comment 1

[Jason Orendorff [:jorendorff]]

I file this now because we've got an embedder rolling his own--and suffering:

http://github.com/meh/lulzjs/blob/93ea51e4a174cf5a3f1c0df9029cb38327de664d/js/lulzjs/lulzjs.cpp#L21-64

Note the bug obtaining `klass`.  :(  Incidentally, the crazy consequences of (unintentionally) creating objects with js_FunctionClass are surprisingly hard to diagnose.

Comment 2

[Jason Orendorff [:jorendorff]]

Attachment: v1

Totally untested.

Comment 3

[Jason Orendorff [:jorendorff]]

(memo to myself) Ash pointed out this is missing CHECK_REQUEST.

Comment 4

[Blake Kaplan (:mrbkap) (inactive)]

jorendorff: any reason (other than the missing CHECK_REQUEST mentioned in comment 3) that this isn't up for review/checkin?

Comment 5

[Ben Newman (:bnewman) (:benjamn)]

I need this, and it works for me.  Let's get it in?

Comment 6

[Jason Orendorff [:jorendorff]]

I'll post a patch with jsapi-test in the next couple hours.

Comment 7

[Jason Orendorff [:jorendorff]]

Attachment: v2

Comment 8

[Ben Newman (:bnewman) (:benjamn)]

What additional review does this patch need?

Comment 9

[Jason Orendorff [:jorendorff]]

It landed in tracemonkey last week.

http://hg.mozilla.org/tracemonkey/rev/869bebcf1f21

Comment 10

[Ben Newman (:bnewman) (:benjamn)]

Also pushed to projects/electrolysis:
http://hg.mozilla.org/projects/electrolysis/rev/faa984df7f45

Comment 11

[Robert Sayre]

http://hg.mozilla.org/mozilla-central/rev/869bebcf1f21