618049 - xpc_qsACString copies its string twice, should only do it once

Status: RESOLVED FIXED

(Core :: XPConnect, defect)

Description

[Ben Turner (not reading bugmail, use the needinfo flag!)]

xpc_qsACString calls JS_EncodeString, which manages a JS engine malloc'd buffer. Then we copy that buffer to nsCString before freeing the JS engine's buffer. We could just call JS_EncodeStringToBuffer and only do it once.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Not quite, because that would be allocated with whatever allocator js uses, while strings will free with the nsMemory allocator, which may not be the same.  :(

Comment 2

[Ben Turner (not reading bugmail, use the needinfo flag!)]

No, you just preallocate the nsCString buffer (via SetCapacity) then JS_EncodeStringToBuffer writes to that.

Comment 3

[Ben Turner (not reading bugmail, use the needinfo flag!)]

(i.e. don't Adopt())

Comment 4

[Boris Zbarsky [:bzbarsky]]

Oh, I see.  Yeah, that sounds good.

Comment 5

[Johnny Stenback (:jst)]

Not blocking on this. I'd approve a safe patch, but won't hold the release for this.

Comment 6

[Johnny Stenback (:jst)]

But Ben, you get to own this either way :)

Comment 7

[Olli Pettay [:smaug][[e-mail]]]

I assume this is still valid.

Comment 8

[BMO Automation]

Per policy at https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Inactive_Bugs. If this bug is not an enhancement request or a bug not present in a supported release of Firefox, then it may be reopened.

Comment 9

[Boris Zbarsky [:bzbarsky]]

Quickstubs are gone, and webidl bindings don't have this problem.