725092 - remove cx argument from principals-related callbacks

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Igor Bukanov]

As a leftover from the multithreaded runtime era JSPRINCIPALS_(HOLD|DROP) still use atomic operations when updating JSPrincipals::refcount. We should remove that. Also it would be nice to remove the unused JSContext *cx parameter that often requires to pass that cx through many layers of API.

Comment 1

[Igor Bukanov]

Attachment: v1

The patch drops atomic operations around JSPrincipals::refcount and removes the cx parameter from  JSPRINCIPALS_(HOLD|DROP). That removal is propagated to the callers when possible.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Is this safe given the comments near the end of bug 143559?  nsPrincipal uses atomic increment/decrement on the JSPrincipals, and could race with main-thread code per that bug, right?

Comment 3

[Igor Bukanov]

(In reply to Boris Zbarsky (:bz) from comment #2)
> Is this safe given the comments near the end of bug 143559?  nsPrincipal
> uses atomic increment/decrement on the JSPrincipals, and could race with
> main-thread code per that bug, right?

You are absolutely right - the principals must continue to use atomic refcounter mutators. So I mutate the bug to be about eliminating unnecessary cx parameter from principals-related methods. That allows to eliminate few useless compartment enter() calls.

Comment 4

[Igor Bukanov]

This was addressed in the bug 730221.