dom/workers/ChromeWorker.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "ChromeWorker.h"
   8
   9 #include "mozilla/dom/WorkerBinding.h"
  10 #include "nsContentUtils.h"
  11 #include "WorkerPrivate.h"
  12
  13 namespace mozilla {
  14 namespace dom {
  15
  16 /* static */
  17 already_AddRefed<ChromeWorker> ChromeWorker::Constructor(
  18     const GlobalObject& aGlobal, const nsAString& aScriptURL,
  19     ErrorResult& aRv) {
  20   JSContext* cx = aGlobal.Context();
  21
  22   RefPtr<WorkerPrivate> workerPrivate = WorkerPrivate::Constructor(
  23       cx, aScriptURL, true /* aIsChromeWorker */, WorkerTypeDedicated,
  24       EmptyString(), VoidCString(), nullptr /*aLoadInfo */, aRv);
  25   if (NS_WARN_IF(aRv.Failed())) {
  26     return nullptr;
  27   }
  28
  29   nsCOMPtr<nsIGlobalObject> globalObject =
  30       do_QueryInterface(aGlobal.GetAsSupports());
  31
  32   RefPtr<ChromeWorker> worker =
  33       new ChromeWorker(globalObject, workerPrivate.forget());
  34   return worker.forget();
  35 }
  36
  37 /* static */
  38 bool ChromeWorker::WorkerAvailable(JSContext* aCx, JSObject* /* unused */) {
  39   // Chrome is always allowed to use workers, and content is never
  40   // allowed to use ChromeWorker, so all we have to check is the
  41   // caller.  However, chrome workers apparently might not have a
  42   // system principal, so we have to check for them manually.
  43   if (NS_IsMainThread()) {
  44     return nsContentUtils::IsSystemCaller(aCx);
  45   }
  46
  47   return GetWorkerPrivateFromContext(aCx)->IsChromeWorker();
  48 }
  49
  50 ChromeWorker::ChromeWorker(nsIGlobalObject* aGlobalObject,
  51                            already_AddRefed<WorkerPrivate> aWorkerPrivate)
  52     : Worker(aGlobalObject, std::move(aWorkerPrivate)) {}
  53
  54 ChromeWorker::~ChromeWorker() = default;
  55
  56 JSObject* ChromeWorker::WrapObject(JSContext* aCx,
  57                                    JS::Handle<JSObject*> aGivenProto) {
  58   JS::Rooted<JSObject*> wrapper(
  59       aCx, ChromeWorker_Binding::Wrap(aCx, this, aGivenProto));
  60   if (wrapper) {
  61     // Most DOM objects don't assume they have a reflector. If they don't have
  62     // one and need one, they create it. But in workers code, we assume that the
  63     // reflector is always present.  In order to guarantee that it's always
  64     // present, we have to preserve it. Otherwise the GC will happily collect it
  65     // as needed.
  66     MOZ_ALWAYS_TRUE(TryPreserveWrapper(wrapper));
  67   }
  68
  69   return wrapper;
  70 }
  71
  72 }  // namespace dom
  73 }  // namespace mozilla