1552268 - Allow omitting `moduleURI` for JSWindowActor declarations

Status: RESOLVED FIXED

(Core :: DOM: Content Processes, enhancement, P2)

Description

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

Sometimes, a custom JS implementation of the JSWindowActor object is unnecessary. For example, it is occasionally desirable to treat one end of the actor as a simple interface with sendAsyncMessage and sendQuery methods, without caring what the other side has to send back.

In these cases, it is currently necessary to create an entire JSM file with an empty subclass of the JSWindowActor object, such as: https://searchfox.org/mozilla-central/rev/94c6b5f06d2464f6780a52f32e917d25ddc30d6b/browser/actors/SubframeCrashParent.jsm#9-10

We should allow the implementor to omit the moduleURI field from the parent and child sides of the actor declaration, and default to generating an empty JSWindowActor object in these cases.

This would take the look of something like this:

1. In WindowGlobalActor::ConstructActor, an additional check would need to be made here that mModuleURI was passed: https://searchfox.org/mozilla-central/rev/94c6b5f06d2464f6780a52f32e917d25ddc30d6b/dom/ipc/WindowGlobalActor.cpp#60
2. If the module URI was not passed, based on the side provided, a basic empty actor must be created & returned. This probably will look something vaguely like this:

if (!side->mModuleURI.WasPassed()) {
  RefPtr<JSWindowActor> actor;
  if (actorType == JSWindowActor::Type::Parent) {
    actor = new JSWindowActorParent();
  } else {
    actor = new JSWindowActorChild();
  }
  JS::Rooted<JS::Value> wrapper(cx);
  if (!ToJSValue(cx, actor, &wrapper)) {
    aRv.NoteJSContextException(cx);
    return;
  }
  MOZ_ASSERT(wrapper.isObject());
  aActor.set(wrapper.toObject());
  return;
}

Comment 1

[John Dai[:jdai]]

Attachment: Bug 1552268 - Allow omitting moduleURI for JSWindowActor declarations;

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9b58a3bb222a
Allow omitting moduleURI for JSWindowActor declarations; r=nika

Comment 3

[Andrei Ciure[:aciure]]

https://hg.mozilla.org/mozilla-central/rev/9b58a3bb222a