1195951 - MediaStreamError contains Heap<T> and is allocated on the stack

Status: RESOLVED FIXED

(Core :: JavaScript: GC, defect)

Description

[Nika Layzell [:nika] (ni? for response)]

dom/media/systemservices/MediaUtils.h:125:15: error: variable of type 'mozilla::dom::MediaStreamError' only valid on the heap
  void Reject(ErrorType rv)
              ^
dom/media/systemservices/MediaUtils.h:125:15: note: value incorrectly allocated in an automatic variable
../../../dist/include/mozilla/dom/MediaStreamError.h:59:7: note: 'mozilla::dom::MediaStreamError' is a heap type because it inherits from a heap type 'nsWrapperCache'
class MediaStreamError final : public nsISupports,
      ^
../../../dist/include/nsWrapperCache.h:352:23: note: 'nsWrapperCache' is a heap type because member 'mWrapper' is a heap type 'JS::Heap<JSObject *>'
  JS::Heap<JSObject*> mWrapper;
                      ^
1 error generated.

Comment 1

[Jon Coppeard (:jonco)]

(In reply to Michael Layzell [:mystor] from comment #0)
> dom/media/systemservices/MediaUtils.h:125:15: error: variable of type
> 'mozilla::dom::MediaStreamError' only valid on the heap
>   void Reject(ErrorType rv)

I'm not familiar with this code, but I doesn't see how the Reject method is going to work.  It takes an ErrorType template argument and assigns it to an nsRefPtr<ErrorType>, and is used with ErrorType as dom::MediaStreamError in the MediaManager class:

  typedef media::Pledge<SourceSet*, dom::MediaStreamError> PledgeSourceSet;

Maybe it should take an nsRefPtr<ErrorType>?  But I don't really know what's going on here.

Looks like this was added in bug 1173255.  jib, do you know how this works?

Comment 2

[Jan-Ivar Bruaroey [:jib] (needinfo? me)]

Attachment: MozReview Request: Bug 1195951 - fix heap type on stack error in MediaUtils' Pledge class

Bug 1195951 - fix heap type on stack error in MediaUtils' Pledge class

Comment 3

[Jan-Ivar Bruaroey [:jib] (needinfo? me)]

This should work better.

Comment 4

[Randell Jesup [:jesup] (needinfo me)]

Comment on attachment 8663420 [details]
MozReview Request: Bug 1195951 - fix heap type on stack error in MediaUtils' Pledge class

https://reviewboard.mozilla.org/r/19793/#review17769

Comment 5

[Jan-Ivar Bruaroey [:jib] (needinfo? me)]

Included in this green try - https://treeherder.mozilla.org/#/jobs?repo=try&revision=a2069a0548b0

Comment 6

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/564f9c049d15

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/564f9c049d15