Now that bug 979481 is landed, we have a null default compartment object for both DOMWindow JSContexts and the SafeJSContext. At that point, we really don't have a use for default compartment objects. Their primary purpose was to specify the compartment that the JSContext should be restored to after JS_SaveFrameChain (which happens during pushing). But I think we can get to a point where we only ever push DOMWindowJSContexts and the SafeJSContext. I think we can probably do the following: (1) Remove the special JSContexts we have for the component loader, sandboxes, etc, and replace them with the SafeJSContext. (2) Fix up any jsapi-tests and whatnot that are sloppy about entering a compartment. (3) Remove default compartment objects, and their associated goop.

\o/

By this point, AutoJSAPI takes care of entering the correct compartment, so this no longer serves a purpose.

\o/

Comment on attachment 8476245 [details] [diff] [review] Part 6 - Remove default compartment objects. v1 \o/ \o/ \o/

ISTR some sort of cruft (my memory is not more specific than that) we had to add to deal with the case where you start in compartment A, auto-enter compartment B, auto-leave compartment B, but since then the default-compartment-object has been changed to C. ExclusiveContext::leaveCompartment seems pretty reasonable nowadays, so maybe it's all gone.

Comment on attachment 8476240 [details] [diff] [review] Part 1 - Remove the JSAutoCompartment from cx pushing. v1 Review of attachment 8476240 [details] [diff] [review]: ----------------------------------------------------------------- Right, we only construct the AutoCxPusher in AutoJSAPI::InitInternal and we always enter a compartment directly afterwards, making this redundant.

Comment on attachment 8476241 [details] [diff] [review] Part 2 - Stop using default compartment objects in nsJSUtils.cpp. v1 Review of attachment 8476241 [details] [diff] [review]: ----------------------------------------------------------------- I've convinced myself that all the callers of nsJSUtils::ReportPendingException will either pass a JSContext that has a script context or pass the SafeJSContext. Again, GetDefaultScopeFromJSContext is only called during an actual push as part of AutoJSAPI::InitInternal, so the JSContext must have a script context or be the SafeJSContext. So in both cases either we would never call js::DefaultObjectForContextOrNull or it would return null anyway.

Comment on attachment 8476242 [details] [diff] [review] Part 3 - Stop using default compartment objects in workers. v1 Review of attachment 8476242 [details] [diff] [review]: ----------------------------------------------------------------- GlobalScope gets set just after the global is created in WorkerPrivate::CreateGlobalScope and (currently until part 6) set as the default compartment object for the context.

Comment on attachment 8476244 [details] [diff] [review] Part 5 - Stop using a default compartment object in the IndexedDB and ProxyAutoConfig JSRuntimes. v1 Review of attachment 8476244 [details] [diff] [review]: ----------------------------------------------------------------- OK, after part 4 it looks like the only place still using DefaultObjectForContextOrNull is JSRuntime::initSelfHosting. This is only called as part of JS_NewContext, which is clearly before we're setting it here.

(In reply to Bob Owen (:bobowen) from comment #13) > I've convinced myself that all the callers of > nsJSUtils::ReportPendingException will either pass a JSContext that has a > script context or pass the SafeJSContext. Yep! Those are now the only 2 contexts left on the main thread. :-)

remote: https://hg.mozilla.org/integration/mozilla-inbound/rev/32f80f97a321 remote: https://hg.mozilla.org/integration/mozilla-inbound/rev/18ffee30e06a remote: https://hg.mozilla.org/integration/mozilla-inbound/rev/0d911a34415d remote: https://hg.mozilla.org/integration/mozilla-inbound/rev/fa5dfae27e49 remote: https://hg.mozilla.org/integration/mozilla-inbound/rev/f4c2b44cc493 remote: https://hg.mozilla.org/integration/mozilla-inbound/rev/ff8835b816c9

https://hg.mozilla.org/mozilla-central/rev/32f80f97a321 https://hg.mozilla.org/mozilla-central/rev/18ffee30e06a https://hg.mozilla.org/mozilla-central/rev/0d911a34415d https://hg.mozilla.org/mozilla-central/rev/fa5dfae27e49 https://hg.mozilla.org/mozilla-central/rev/f4c2b44cc493 https://hg.mozilla.org/mozilla-central/rev/ff8835b816c9