Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1925 insertions, 0 deletions

diff --git a/dom/serviceworkers/ServiceWorkerOp.cpp b/dom/serviceworkers/ServiceWorkerOp.cpp
new file mode 100644
index 0000000000..8811404a0f
--- /dev/null
+++ b/dom/serviceworkers/ServiceWorkerOp.cpp
@@ -0,0 +1,1925 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ServiceWorkerOp.h"
+
+#include <utility>
+
+#include "ServiceWorkerOpPromise.h"
+#include "js/Exception.h"  // JS::ExceptionStack, JS::StealPendingExceptionStack
+#include "jsapi.h"
+
+#include "nsCOMPtr.h"
+#include "nsContentUtils.h"
+#include "nsDebug.h"
+#include "nsError.h"
+#include "nsINamed.h"
+#include "nsIPushErrorReporter.h"
+#include "nsISupportsImpl.h"
+#include "nsITimer.h"
+#include "nsIURI.h"
+#include "nsServiceManagerUtils.h"
+#include "nsTArray.h"
+#include "nsThreadUtils.h"
+
+#include "ServiceWorkerCloneData.h"
+#include "ServiceWorkerShutdownState.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/CycleCollectedJSContext.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/OwningNonNull.h"
+#include "mozilla/SchedulerGroup.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/Unused.h"
+#include "mozilla/dom/BindingDeclarations.h"
+#include "mozilla/dom/Client.h"
+#include "mozilla/dom/ExtendableMessageEventBinding.h"
+#include "mozilla/dom/FetchEventBinding.h"
+#include "mozilla/dom/FetchEventOpProxyChild.h"
+#include "mozilla/dom/InternalHeaders.h"
+#include "mozilla/dom/InternalRequest.h"
+#include "mozilla/dom/InternalResponse.h"
+#include "mozilla/dom/Notification.h"
+#include "mozilla/dom/NotificationEvent.h"
+#include "mozilla/dom/NotificationEventBinding.h"
+#include "mozilla/dom/PerformanceTiming.h"
+#include "mozilla/dom/PerformanceStorage.h"
+#include "mozilla/dom/PushEventBinding.h"
+#include "mozilla/dom/RemoteWorkerChild.h"
+#include "mozilla/dom/RemoteWorkerService.h"
+#include "mozilla/dom/Request.h"
+#include "mozilla/dom/Response.h"
+#include "mozilla/dom/RootedDictionary.h"
+#include "mozilla/dom/SafeRefPtr.h"
+#include "mozilla/dom/ServiceWorkerBinding.h"
+#include "mozilla/dom/ServiceWorkerGlobalScopeBinding.h"
+#include "mozilla/dom/WorkerCommon.h"
+#include "mozilla/dom/WorkerRef.h"
+#include "mozilla/dom/WorkerScope.h"
+#include "mozilla/extensions/ExtensionBrowser.h"
+#include "mozilla/ipc/IPCStreamUtils.h"
+
+namespace mozilla::dom {
+
+namespace {
+
+class ExtendableEventKeepAliveHandler final
+    : public ExtendableEvent::ExtensionsHandler,
+      public PromiseNativeHandler {
+ public:
+  NS_DECL_ISUPPORTS
+
+  static RefPtr<ExtendableEventKeepAliveHandler> Create(
+      RefPtr<ExtendableEventCallback> aCallback) {
+    MOZ_ASSERT(IsCurrentThreadRunningWorker());
+
+    RefPtr<ExtendableEventKeepAliveHandler> self =
+        new ExtendableEventKeepAliveHandler(std::move(aCallback));
+
+    self->mWorkerRef = StrongWorkerRef::Create(
+        GetCurrentThreadWorkerPrivate(), "ExtendableEventKeepAliveHandler",
+        [self]() { self->Cleanup(); });
+
+    if (NS_WARN_IF(!self->mWorkerRef)) {
+      return nullptr;
+    }
+
+    return self;
+  }
+
+  /**
+   * ExtendableEvent::ExtensionsHandler interface
+   */
+  bool WaitOnPromise(Promise& aPromise) override {
+    if (!mAcceptingPromises) {
+      MOZ_ASSERT(!GetDispatchFlag());
+      MOZ_ASSERT(!mSelfRef, "We shouldn't be holding a self reference!");
+      return false;
+    }
+
+    if (!mSelfRef) {
+      MOZ_ASSERT(!mPendingPromisesCount);
+      mSelfRef = this;
+    }
+
+    ++mPendingPromisesCount;
+    aPromise.AppendNativeHandler(this);
+
+    return true;
+  }
+
+  /**
+   * PromiseNativeHandler interface
+   */
+  void ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                        ErrorResult& aRv) override {
+    RemovePromise(Resolved);
+  }
+
+  void RejectedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                        ErrorResult& aRv) override {
+    RemovePromise(Rejected);
+  }
+
+  void MaybeDone() {
+    MOZ_ASSERT(IsCurrentThreadRunningWorker());
+    MOZ_ASSERT(!GetDispatchFlag());
+
+    if (mPendingPromisesCount) {
+      return;
+    }
+
+    if (mCallback) {
+      mCallback->FinishedWithResult(mRejected ? Rejected : Resolved);
+      mCallback = nullptr;
+    }
+
+    Cleanup();
+  }
+
+ private:
+  /**
+   * This class is useful for the case where pending microtasks will continue
+   * extending the event, which means that the event is not "done." For example:
+   *
+   * // `e` is an ExtendableEvent, `p` is a Promise
+   * e.waitUntil(p);
+   * p.then(() => e.waitUntil(otherPromise));
+   */
+  class MaybeDoneRunner : public MicroTaskRunnable {
+   public:
+    explicit MaybeDoneRunner(RefPtr<ExtendableEventKeepAliveHandler> aHandler)
+        : mHandler(std::move(aHandler)) {}
+
+    void Run(AutoSlowOperation& /* unused */) override {
+      mHandler->MaybeDone();
+    }
+
+   private:
+    RefPtr<ExtendableEventKeepAliveHandler> mHandler;
+  };
+
+  explicit ExtendableEventKeepAliveHandler(
+      RefPtr<ExtendableEventCallback> aCallback)
+      : mCallback(std::move(aCallback)) {}
+
+  ~ExtendableEventKeepAliveHandler() { Cleanup(); }
+
+  void Cleanup() {
+    MOZ_ASSERT(IsCurrentThreadRunningWorker());
+
+    if (mCallback) {
+      mCallback->FinishedWithResult(Rejected);
+    }
+
+    mSelfRef = nullptr;
+    mWorkerRef = nullptr;
+    mCallback = nullptr;
+    mAcceptingPromises = false;
+  }
+
+  void RemovePromise(ExtendableEventResult aResult) {
+    MOZ_ASSERT(IsCurrentThreadRunningWorker());
+    MOZ_DIAGNOSTIC_ASSERT(mPendingPromisesCount > 0);
+
+    // NOTE: mSelfRef can be nullptr here if MaybeCleanup() was just called
+    // before a promise settled. This can happen, for example, if the worker
+    // thread is being terminated for running too long, browser shutdown, etc.
+
+    mRejected |= (aResult == Rejected);
+
+    --mPendingPromisesCount;
+    if (mPendingPromisesCount || GetDispatchFlag()) {
+      return;
+    }
+
+    CycleCollectedJSContext* cx = CycleCollectedJSContext::Get();
+    MOZ_ASSERT(cx);
+
+    RefPtr<MaybeDoneRunner> r = new MaybeDoneRunner(this);
+    cx->DispatchToMicroTask(r.forget());
+  }
+
+  /**
+   * We start holding a self reference when the first extension promise is
+   * added, and this reference is released when the last promise settles or
+   * when the worker is shutting down.
+   *
+   * This is needed in the case that we're waiting indefinitely on a to-be-GC'ed
+   * promise that's no longer reachable and will never be settled.
+   */
+  RefPtr<ExtendableEventKeepAliveHandler> mSelfRef;
+
+  RefPtr<StrongWorkerRef> mWorkerRef;
+
+  RefPtr<ExtendableEventCallback> mCallback;
+
+  uint32_t mPendingPromisesCount = 0;
+
+  bool mRejected = false;
+  bool mAcceptingPromises = true;
+};
+
+NS_IMPL_ISUPPORTS0(ExtendableEventKeepAliveHandler)
+
+nsresult DispatchExtendableEventOnWorkerScope(
+    JSContext* aCx, WorkerGlobalScope* aWorkerScope, ExtendableEvent* aEvent,
+    RefPtr<ExtendableEventCallback> aCallback) {
+  MOZ_ASSERT(aCx);
+  MOZ_ASSERT(aWorkerScope);
+  MOZ_ASSERT(aEvent);
+
+  nsCOMPtr<nsIGlobalObject> globalObject = aWorkerScope;
+  WidgetEvent* internalEvent = aEvent->WidgetEventPtr();
+
+  RefPtr<ExtendableEventKeepAliveHandler> keepAliveHandler =
+      ExtendableEventKeepAliveHandler::Create(std::move(aCallback));
+  if (NS_WARN_IF(!keepAliveHandler)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // This must be always set *before* dispatching the event, otherwise
+  // waitUntil() calls will fail.
+  aEvent->SetKeepAliveHandler(keepAliveHandler);
+
+  ErrorResult result;
+  aWorkerScope->DispatchEvent(*aEvent, result);
+  if (NS_WARN_IF(result.Failed())) {
+    result.SuppressException();
+    return NS_ERROR_FAILURE;
+  }
+
+  keepAliveHandler->MaybeDone();
+
+  // We don't block the event when getting an exception but still report the
+  // error message. NOTE: this will not stop the event.
+  if (internalEvent->mFlags.mExceptionWasRaised) {
+    return NS_ERROR_XPC_JS_THREW_EXCEPTION;
+  }
+
+  return NS_OK;
+}
+
+bool DispatchFailed(nsresult aStatus) {
+  return NS_FAILED(aStatus) && aStatus != NS_ERROR_XPC_JS_THREW_EXCEPTION;
+}
+
+}  // anonymous namespace
+
+class ServiceWorkerOp::ServiceWorkerOpRunnable final
+    : public WorkerDebuggeeRunnable {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+
+  ServiceWorkerOpRunnable(RefPtr<ServiceWorkerOp> aOwner,
+                          WorkerPrivate* aWorkerPrivate)
+      : WorkerDebuggeeRunnable(aWorkerPrivate, "ServiceWorkerOpRunnable",
+                               WorkerThread),
+        mOwner(std::move(aOwner)) {
+    AssertIsOnMainThread();
+    MOZ_ASSERT(mOwner);
+    MOZ_ASSERT(aWorkerPrivate);
+  }
+
+ private:
+  ~ServiceWorkerOpRunnable() = default;
+
+  bool WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+    MOZ_ASSERT(mOwner);
+
+    if (aWorkerPrivate->GlobalScope()->IsDying()) {
+      Unused << Cancel();
+      return true;
+    }
+
+    bool rv = mOwner->Exec(aCx, aWorkerPrivate);
+    Unused << NS_WARN_IF(!rv);
+    mOwner = nullptr;
+
+    return rv;
+  }
+
+  nsresult Cancel() override {
+    MOZ_ASSERT(mOwner);
+
+    mOwner->RejectAll(NS_ERROR_DOM_ABORT_ERR);
+    mOwner = nullptr;
+
+    return NS_OK;
+  }
+
+  RefPtr<ServiceWorkerOp> mOwner;
+};
+
+NS_IMPL_ISUPPORTS_INHERITED0(ServiceWorkerOp::ServiceWorkerOpRunnable,
+                             WorkerRunnable)
+
+bool ServiceWorkerOp::MaybeStart(RemoteWorkerChild* aOwner,
+                                 RemoteWorkerChild::State& aState) {
+  MOZ_ASSERT(!mStarted);
+  MOZ_ASSERT(aOwner);
+  MOZ_ASSERT(aOwner->GetActorEventTarget()->IsOnCurrentThread());
+
+  auto launcherData = aOwner->mLauncherData.Access();
+
+  if (NS_WARN_IF(!aOwner->CanSend())) {
+    RejectAll(NS_ERROR_DOM_ABORT_ERR);
+    mStarted = true;
+    return true;
+  }
+
+  // Allow termination to happen while the Service Worker is initializing.
+  if (aState.is<Pending>() && !IsTerminationOp()) {
+    return false;
+  }
+
+  if (NS_WARN_IF(aState.is<RemoteWorkerChild::Canceled>()) ||
+      NS_WARN_IF(aState.is<RemoteWorkerChild::Killed>())) {
+    RejectAll(NS_ERROR_DOM_INVALID_STATE_ERR);
+    mStarted = true;
+    return true;
+  }
+
+  MOZ_ASSERT(aState.is<RemoteWorkerChild::Running>() || IsTerminationOp());
+
+  RefPtr<ServiceWorkerOp> self = this;
+
+  if (IsTerminationOp()) {
+    aOwner->GetTerminationPromise()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [self](
+            const GenericNonExclusivePromise::ResolveOrRejectValue& aResult) {
+          MaybeReportServiceWorkerShutdownProgress(self->mArgs, true);
+
+          MOZ_ASSERT(!self->mPromiseHolder.IsEmpty());
+
+          if (NS_WARN_IF(aResult.IsReject())) {
+            self->mPromiseHolder.Reject(aResult.RejectValue(), __func__);
+            return;
+          }
+
+          self->mPromiseHolder.Resolve(NS_OK, __func__);
+        });
+  }
+
+  // NewRunnableMethod doesn't work here because the template does not appear to
+  // be able to deal with the owner argument having storage as a RefPtr but
+  // with the method taking a RefPtr&.
+  RefPtr<RemoteWorkerChild> owner = aOwner;
+  nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
+      __func__, [self = std::move(self), owner = std::move(owner)]() mutable {
+        self->StartOnMainThread(owner);
+      });
+
+  mStarted = true;
+
+  MOZ_ALWAYS_SUCCEEDS(SchedulerGroup::Dispatch(r.forget()));
+  return true;
+}
+
+void ServiceWorkerOp::StartOnMainThread(RefPtr<RemoteWorkerChild>& aOwner) {
+  MaybeReportServiceWorkerShutdownProgress(mArgs);
+
+  {
+    auto lock = aOwner->mState.Lock();
+
+    if (NS_WARN_IF(!lock->is<Running>() && !IsTerminationOp())) {
+      RejectAll(NS_ERROR_DOM_INVALID_STATE_ERR);
+      return;
+    }
+  }
+
+  if (IsTerminationOp()) {
+    aOwner->CloseWorkerOnMainThread();
+  } else {
+    auto lock = aOwner->mState.Lock();
+    MOZ_ASSERT(lock->is<Running>());
+
+    RefPtr<WorkerRunnable> workerRunnable =
+        GetRunnable(lock->as<Running>().mWorkerPrivate);
+
+    if (NS_WARN_IF(!workerRunnable->Dispatch())) {
+      RejectAll(NS_ERROR_FAILURE);
+    }
+  }
+}
+
+void ServiceWorkerOp::Cancel() { RejectAll(NS_ERROR_DOM_ABORT_ERR); }
+
+ServiceWorkerOp::ServiceWorkerOp(
+    ServiceWorkerOpArgs&& aArgs,
+    std::function<void(const ServiceWorkerOpResult&)>&& aCallback)
+    : mArgs(std::move(aArgs)) {
+  MOZ_ASSERT(RemoteWorkerService::Thread()->IsOnCurrentThread());
+
+  RefPtr<ServiceWorkerOpPromise> promise = mPromiseHolder.Ensure(__func__);
+
+  promise->Then(
+      GetCurrentSerialEventTarget(), __func__,
+      [callback = std::move(aCallback)](
+          ServiceWorkerOpPromise::ResolveOrRejectValue&& aResult) mutable {
+        if (NS_WARN_IF(aResult.IsReject())) {
+          MOZ_ASSERT(NS_FAILED(aResult.RejectValue()));
+          callback(aResult.RejectValue());
+          return;
+        }
+
+        callback(aResult.ResolveValue());
+      });
+}
+
+ServiceWorkerOp::~ServiceWorkerOp() {
+  Unused << NS_WARN_IF(!mPromiseHolder.IsEmpty());
+  mPromiseHolder.RejectIfExists(NS_ERROR_DOM_ABORT_ERR, __func__);
+}
+
+bool ServiceWorkerOp::Started() const {
+  MOZ_ASSERT(RemoteWorkerService::Thread()->IsOnCurrentThread());
+
+  return mStarted;
+}
+
+bool ServiceWorkerOp::IsTerminationOp() const {
+  return mArgs.type() ==
+         ServiceWorkerOpArgs::TServiceWorkerTerminateWorkerOpArgs;
+}
+
+RefPtr<WorkerRunnable> ServiceWorkerOp::GetRunnable(
+    WorkerPrivate* aWorkerPrivate) {
+  AssertIsOnMainThread();
+  MOZ_ASSERT(aWorkerPrivate);
+
+  return new ServiceWorkerOpRunnable(this, aWorkerPrivate);
+}
+
+void ServiceWorkerOp::RejectAll(nsresult aStatus) {
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+  mPromiseHolder.Reject(aStatus, __func__);
+}
+
+class CheckScriptEvaluationOp final : public ServiceWorkerOp {
+  using ServiceWorkerOp::ServiceWorkerOp;
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CheckScriptEvaluationOp, override)
+
+ private:
+  ~CheckScriptEvaluationOp() = default;
+
+  bool Exec(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+    MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+    ServiceWorkerCheckScriptEvaluationOpResult result;
+    result.workerScriptExecutedSuccessfully() =
+        aWorkerPrivate->WorkerScriptExecutedSuccessfully();
+    result.fetchHandlerWasAdded() = aWorkerPrivate->FetchHandlerWasAdded();
+
+    mPromiseHolder.Resolve(result, __func__);
+
+    return true;
+  }
+};
+
+class TerminateServiceWorkerOp final : public ServiceWorkerOp {
+  using ServiceWorkerOp::ServiceWorkerOp;
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(TerminateServiceWorkerOp, override)
+
+ private:
+  ~TerminateServiceWorkerOp() = default;
+
+  bool Exec(JSContext*, WorkerPrivate*) override {
+    MOZ_ASSERT_UNREACHABLE(
+        "Worker termination should be handled in "
+        "`ServiceWorkerOp::MaybeStart()`");
+
+    return false;
+  }
+};
+
+class UpdateServiceWorkerStateOp final : public ServiceWorkerOp {
+  using ServiceWorkerOp::ServiceWorkerOp;
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(UpdateServiceWorkerStateOp, override);
+
+ private:
+  class UpdateStateOpRunnable final : public MainThreadWorkerControlRunnable {
+   public:
+    NS_DECL_ISUPPORTS_INHERITED
+
+    UpdateStateOpRunnable(RefPtr<UpdateServiceWorkerStateOp> aOwner,
+                          WorkerPrivate* aWorkerPrivate)
+        : MainThreadWorkerControlRunnable(aWorkerPrivate),
+          mOwner(std::move(aOwner)) {
+      AssertIsOnMainThread();
+      MOZ_ASSERT(mOwner);
+      MOZ_ASSERT(aWorkerPrivate);
+    }
+
+   private:
+    ~UpdateStateOpRunnable() = default;
+
+    bool WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+      MOZ_ASSERT(aWorkerPrivate);
+      aWorkerPrivate->AssertIsOnWorkerThread();
+      MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+
+      if (mOwner) {
+        Unused << mOwner->Exec(aCx, aWorkerPrivate);
+        mOwner = nullptr;
+      }
+
+      return true;
+    }
+
+    nsresult Cancel() override {
+      MOZ_ASSERT(mOwner);
+
+      mOwner->RejectAll(NS_ERROR_DOM_ABORT_ERR);
+      mOwner = nullptr;
+
+      return NS_OK;
+    }
+
+    RefPtr<UpdateServiceWorkerStateOp> mOwner;
+  };
+
+  ~UpdateServiceWorkerStateOp() = default;
+
+  RefPtr<WorkerRunnable> GetRunnable(WorkerPrivate* aWorkerPrivate) override {
+    AssertIsOnMainThread();
+    MOZ_ASSERT(aWorkerPrivate);
+    MOZ_ASSERT(mArgs.type() ==
+               ServiceWorkerOpArgs::TServiceWorkerUpdateStateOpArgs);
+
+    return new UpdateStateOpRunnable(this, aWorkerPrivate);
+  }
+
+  bool Exec(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+    MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+    ServiceWorkerState state =
+        mArgs.get_ServiceWorkerUpdateStateOpArgs().state();
+    aWorkerPrivate->UpdateServiceWorkerState(state);
+
+    mPromiseHolder.Resolve(NS_OK, __func__);
+
+    return true;
+  }
+};
+
+NS_IMPL_ISUPPORTS_INHERITED0(UpdateServiceWorkerStateOp::UpdateStateOpRunnable,
+                             MainThreadWorkerControlRunnable)
+
+void ExtendableEventOp::FinishedWithResult(ExtendableEventResult aResult) {
+  MOZ_ASSERT(IsCurrentThreadRunningWorker());
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+  mPromiseHolder.Resolve(aResult == Resolved ? NS_OK : NS_ERROR_FAILURE,
+                         __func__);
+}
+
+class LifeCycleEventOp final : public ExtendableEventOp {
+  using ExtendableEventOp::ExtendableEventOp;
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(LifeCycleEventOp, override)
+
+ private:
+  ~LifeCycleEventOp() = default;
+
+  bool Exec(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+    MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+    RefPtr<ExtendableEvent> event;
+    RefPtr<EventTarget> target = aWorkerPrivate->GlobalScope();
+
+    const nsString& eventName =
+        mArgs.get_ServiceWorkerLifeCycleEventOpArgs().eventName();
+
+    if (eventName.EqualsASCII("install") || eventName.EqualsASCII("activate")) {
+      ExtendableEventInit init;
+      init.mBubbles = false;
+      init.mCancelable = false;
+      event = ExtendableEvent::Constructor(target, eventName, init);
+    } else {
+      MOZ_CRASH("Unexpected lifecycle event");
+    }
+
+    event->SetTrusted(true);
+
+    nsresult rv = DispatchExtendableEventOnWorkerScope(
+        aCx, aWorkerPrivate->GlobalScope(), event, this);
+
+    if (NS_WARN_IF(DispatchFailed(rv))) {
+      RejectAll(rv);
+    }
+
+    return !DispatchFailed(rv);
+  }
+};
+
+/**
+ * PushEventOp
+ */
+class PushEventOp final : public ExtendableEventOp {
+  using ExtendableEventOp::ExtendableEventOp;
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(PushEventOp, override)
+
+ private:
+  ~PushEventOp() = default;
+
+  bool Exec(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+    MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+    ErrorResult result;
+
+    auto scopeExit = MakeScopeExit([&] {
+      MOZ_ASSERT(result.Failed());
+
+      RejectAll(result.StealNSResult());
+      ReportError(aWorkerPrivate);
+    });
+
+    const ServiceWorkerPushEventOpArgs& args =
+        mArgs.get_ServiceWorkerPushEventOpArgs();
+
+    RootedDictionary<PushEventInit> pushEventInit(aCx);
+
+    if (args.data().type() != OptionalPushData::Tvoid_t) {
+      const auto& bytes = args.data().get_ArrayOfuint8_t();
+      JSObject* data = Uint8Array::Create(aCx, bytes, result);
+
+      if (result.Failed()) {
+        return false;
+      }
+
+      DebugOnly<bool> inited =
+          pushEventInit.mData.Construct().SetAsArrayBufferView().Init(data);
+      MOZ_ASSERT(inited);
+    }
+
+    pushEventInit.mBubbles = false;
+    pushEventInit.mCancelable = false;
+
+    GlobalObject globalObj(aCx, aWorkerPrivate->GlobalScope()->GetWrapper());
+    RefPtr<PushEvent> pushEvent =
+        PushEvent::Constructor(globalObj, u"push"_ns, pushEventInit, result);
+
+    if (NS_WARN_IF(result.Failed())) {
+      return false;
+    }
+
+    pushEvent->SetTrusted(true);
+
+    scopeExit.release();
+
+    nsresult rv = DispatchExtendableEventOnWorkerScope(
+        aCx, aWorkerPrivate->GlobalScope(), pushEvent, this);
+
+    if (NS_FAILED(rv)) {
+      if (NS_WARN_IF(DispatchFailed(rv))) {
+        RejectAll(rv);
+      }
+
+      // We don't cancel WorkerPrivate when catching an exception.
+      ReportError(aWorkerPrivate,
+                  nsIPushErrorReporter::DELIVERY_UNCAUGHT_EXCEPTION);
+    }
+
+    return !DispatchFailed(rv);
+  }
+
+  void FinishedWithResult(ExtendableEventResult aResult) override {
+    MOZ_ASSERT(IsCurrentThreadRunningWorker());
+
+    WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
+
+    if (aResult == Rejected) {
+      ReportError(workerPrivate,
+                  nsIPushErrorReporter::DELIVERY_UNHANDLED_REJECTION);
+    }
+
+    ExtendableEventOp::FinishedWithResult(aResult);
+  }
+
+  void ReportError(
+      WorkerPrivate* aWorkerPrivate,
+      uint16_t aError = nsIPushErrorReporter::DELIVERY_INTERNAL_ERROR) {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+
+    if (NS_WARN_IF(aError > nsIPushErrorReporter::DELIVERY_INTERNAL_ERROR) ||
+        mArgs.get_ServiceWorkerPushEventOpArgs().messageId().IsEmpty()) {
+      return;
+    }
+
+    nsString messageId = mArgs.get_ServiceWorkerPushEventOpArgs().messageId();
+    nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
+        __func__, [messageId = std::move(messageId), error = aError] {
+          nsCOMPtr<nsIPushErrorReporter> reporter =
+              do_GetService("@mozilla.org/push/Service;1");
+
+          if (reporter) {
+            nsresult rv = reporter->ReportDeliveryError(messageId, error);
+            Unused << NS_WARN_IF(NS_FAILED(rv));
+          }
+        });
+
+    MOZ_ALWAYS_SUCCEEDS(aWorkerPrivate->DispatchToMainThread(r.forget()));
+  }
+};
+
+class PushSubscriptionChangeEventOp final : public ExtendableEventOp {
+  using ExtendableEventOp::ExtendableEventOp;
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(PushSubscriptionChangeEventOp, override)
+
+ private:
+  ~PushSubscriptionChangeEventOp() = default;
+
+  bool Exec(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+    MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+    RefPtr<EventTarget> target = aWorkerPrivate->GlobalScope();
+
+    ExtendableEventInit init;
+    init.mBubbles = false;
+    init.mCancelable = false;
+
+    RefPtr<ExtendableEvent> event = ExtendableEvent::Constructor(
+        target, u"pushsubscriptionchange"_ns, init);
+    event->SetTrusted(true);
+
+    nsresult rv = DispatchExtendableEventOnWorkerScope(
+        aCx, aWorkerPrivate->GlobalScope(), event, this);
+
+    if (NS_WARN_IF(DispatchFailed(rv))) {
+      RejectAll(rv);
+    }
+
+    return !DispatchFailed(rv);
+  }
+};
+
+class NotificationEventOp : public ExtendableEventOp,
+                            public nsITimerCallback,
+                            public nsINamed {
+  using ExtendableEventOp::ExtendableEventOp;
+
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+ private:
+  ~NotificationEventOp() {
+    MOZ_DIAGNOSTIC_ASSERT(!mTimer);
+    MOZ_DIAGNOSTIC_ASSERT(!mWorkerRef);
+  }
+
+  void ClearWindowAllowed(WorkerPrivate* aWorkerPrivate) {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+
+    if (!mTimer) {
+      return;
+    }
+
+    // This might be executed after the global was unrooted, in which case
+    // GlobalScope() will return null. Making the check here just to be safe.
+    WorkerGlobalScope* globalScope = aWorkerPrivate->GlobalScope();
+    if (!globalScope) {
+      return;
+    }
+
+    globalScope->ConsumeWindowInteraction();
+    mTimer->Cancel();
+    mTimer = nullptr;
+
+    mWorkerRef = nullptr;
+  }
+
+  void StartClearWindowTimer(WorkerPrivate* aWorkerPrivate) {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(!mTimer);
+
+    nsresult rv;
+    nsCOMPtr<nsITimer> timer =
+        NS_NewTimer(aWorkerPrivate->ControlEventTarget());
+    if (NS_WARN_IF(!timer)) {
+      return;
+    }
+
+    MOZ_ASSERT(!mWorkerRef);
+    RefPtr<NotificationEventOp> self = this;
+    mWorkerRef = StrongWorkerRef::Create(
+        aWorkerPrivate, "NotificationEventOp", [self = std::move(self)] {
+          // We could try to hold the worker alive until the timer fires, but
+          // other APIs are not likely to work in this partially shutdown state.
+          // We might as well let the worker thread exit.
+          self->ClearWindowAllowed(self->mWorkerRef->Private());
+        });
+
+    if (!mWorkerRef) {
+      return;
+    }
+
+    aWorkerPrivate->GlobalScope()->AllowWindowInteraction();
+    timer.swap(mTimer);
+
+    // We swap first and then initialize the timer so that even if initializing
+    // fails, we still clean the interaction count correctly.
+    uint32_t delay = mArgs.get_ServiceWorkerNotificationEventOpArgs()
+                         .disableOpenClickDelay();
+    rv = mTimer->InitWithCallback(this, delay, nsITimer::TYPE_ONE_SHOT);
+
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      ClearWindowAllowed(aWorkerPrivate);
+      return;
+    }
+  }
+
+  // ExtendableEventOp interface
+  bool Exec(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+    MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+    RefPtr<EventTarget> target = aWorkerPrivate->GlobalScope();
+
+    ServiceWorkerNotificationEventOpArgs& args =
+        mArgs.get_ServiceWorkerNotificationEventOpArgs();
+
+    auto result = Notification::ConstructFromFields(
+        aWorkerPrivate->GlobalScope(), args.id(), args.title(), args.dir(),
+        args.lang(), args.body(), args.tag(), args.icon(), args.data(),
+        args.scope());
+
+    if (NS_WARN_IF(result.isErr())) {
+      return false;
+    }
+
+    NotificationEventInit init;
+    init.mNotification = result.unwrap();
+    init.mBubbles = false;
+    init.mCancelable = false;
+
+    RefPtr<NotificationEvent> notificationEvent =
+        NotificationEvent::Constructor(target, args.eventName(), init);
+
+    notificationEvent->SetTrusted(true);
+
+    if (args.eventName().EqualsLiteral("notificationclick")) {
+      StartClearWindowTimer(aWorkerPrivate);
+    }
+
+    nsresult rv = DispatchExtendableEventOnWorkerScope(
+        aCx, aWorkerPrivate->GlobalScope(), notificationEvent, this);
+
+    if (NS_WARN_IF(DispatchFailed(rv))) {
+      // This will reject mPromiseHolder.
+      FinishedWithResult(Rejected);
+    }
+
+    return !DispatchFailed(rv);
+  }
+
+  void FinishedWithResult(ExtendableEventResult aResult) override {
+    MOZ_ASSERT(IsCurrentThreadRunningWorker());
+
+    WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
+    MOZ_ASSERT(workerPrivate);
+
+    ClearWindowAllowed(workerPrivate);
+
+    ExtendableEventOp::FinishedWithResult(aResult);
+  }
+
+  // nsITimerCallback interface
+  NS_IMETHOD Notify(nsITimer* aTimer) override {
+    MOZ_DIAGNOSTIC_ASSERT(mTimer == aTimer);
+    WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
+    ClearWindowAllowed(workerPrivate);
+    return NS_OK;
+  }
+
+  // nsINamed interface
+  NS_IMETHOD GetName(nsACString& aName) override {
+    aName.AssignLiteral("NotificationEventOp");
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsITimer> mTimer;
+  RefPtr<StrongWorkerRef> mWorkerRef;
+};
+
+NS_IMPL_ISUPPORTS(NotificationEventOp, nsITimerCallback, nsINamed)
+
+class MessageEventOp final : public ExtendableEventOp {
+  using ExtendableEventOp::ExtendableEventOp;
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MessageEventOp, override)
+
+  MessageEventOp(ServiceWorkerOpArgs&& aArgs,
+                 std::function<void(const ServiceWorkerOpResult&)>&& aCallback)
+      : ExtendableEventOp(std::move(aArgs), std::move(aCallback)),
+        mData(new ServiceWorkerCloneData()) {
+    mData->CopyFromClonedMessageData(
+        mArgs.get_ServiceWorkerMessageEventOpArgs().clonedData());
+  }
+
+ private:
+  ~MessageEventOp() = default;
+
+  bool Exec(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+    MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+    JS::Rooted<JS::Value> messageData(aCx);
+    nsCOMPtr<nsIGlobalObject> sgo = aWorkerPrivate->GlobalScope();
+    ErrorResult rv;
+    if (!mData->IsErrorMessageData()) {
+      mData->Read(aCx, &messageData, rv);
+    }
+
+    // If mData is an error message data, then it means that it failed to
+    // serialize on the caller side because it contains a shared memory object.
+    // If deserialization fails, we will fire a messageerror event.
+    const bool deserializationFailed =
+        rv.Failed() || mData->IsErrorMessageData();
+
+    Sequence<OwningNonNull<MessagePort>> ports;
+    if (!mData->TakeTransferredPortsAsSequence(ports)) {
+      RejectAll(NS_ERROR_FAILURE);
+      rv.SuppressException();
+      return false;
+    }
+
+    RootedDictionary<ExtendableMessageEventInit> init(aCx);
+
+    init.mBubbles = false;
+    init.mCancelable = false;
+
+    // On a messageerror event, we disregard ports:
+    // https://w3c.github.io/ServiceWorker/#service-worker-postmessage
+    if (!deserializationFailed) {
+      init.mData = messageData;
+      init.mPorts = std::move(ports);
+    }
+
+    nsCOMPtr<nsIURI> url;
+    nsresult result = NS_NewURI(getter_AddRefs(url),
+                                mArgs.get_ServiceWorkerMessageEventOpArgs()
+                                    .clientInfoAndState()
+                                    .info()
+                                    .url());
+    if (NS_WARN_IF(NS_FAILED(result))) {
+      RejectAll(result);
+      rv.SuppressException();
+      return false;
+    }
+
+    OriginAttributes attrs;
+    nsCOMPtr<nsIPrincipal> principal =
+        BasePrincipal::CreateContentPrincipal(url, attrs);
+    if (!principal) {
+      return false;
+    }
+
+    nsCString origin;
+    result = principal->GetOriginNoSuffix(origin);
+    if (NS_WARN_IF(NS_FAILED(result))) {
+      RejectAll(result);
+      rv.SuppressException();
+      return false;
+    }
+
+    CopyUTF8toUTF16(origin, init.mOrigin);
+
+    init.mSource.SetValue().SetAsClient() = new Client(
+        sgo, mArgs.get_ServiceWorkerMessageEventOpArgs().clientInfoAndState());
+
+    rv.SuppressException();
+    RefPtr<EventTarget> target = aWorkerPrivate->GlobalScope();
+    RefPtr<ExtendableMessageEvent> extendableEvent =
+        ExtendableMessageEvent::Constructor(
+            target, deserializationFailed ? u"messageerror"_ns : u"message"_ns,
+            init);
+
+    extendableEvent->SetTrusted(true);
+
+    nsresult rv2 = DispatchExtendableEventOnWorkerScope(
+        aCx, aWorkerPrivate->GlobalScope(), extendableEvent, this);
+
+    if (NS_WARN_IF(DispatchFailed(rv2))) {
+      RejectAll(rv2);
+    }
+
+    return !DispatchFailed(rv2);
+  }
+
+  RefPtr<ServiceWorkerCloneData> mData;
+};
+
+/**
+ * Used for ScopeExit-style network request cancelation in
+ * `ResolvedCallback()` (e.g. if `FetchEvent::RespondWith()` is resolved with
+ * a non-JS object).
+ */
+class MOZ_STACK_CLASS FetchEventOp::AutoCancel {
+ public:
+  explicit AutoCancel(FetchEventOp* aOwner)
+      : mOwner(aOwner),
+        mLine(0),
+        mColumn(0),
+        mMessageName("InterceptionFailedWithURL"_ns) {
+    MOZ_ASSERT(IsCurrentThreadRunningWorker());
+    MOZ_ASSERT(mOwner);
+
+    nsAutoString requestURL;
+    mOwner->GetRequestURL(requestURL);
+    mParams.AppendElement(requestURL);
+  }
+
+  ~AutoCancel() {
+    if (mOwner) {
+      if (mSourceSpec.IsEmpty()) {
+        mOwner->AsyncLog(mMessageName, std::move(mParams));
+      } else {
+        mOwner->AsyncLog(mSourceSpec, mLine, mColumn, mMessageName,
+                         std::move(mParams));
+      }
+
+      MOZ_ASSERT(!mOwner->mRespondWithPromiseHolder.IsEmpty());
+      mOwner->mHandled->MaybeRejectWithNetworkError("AutoCancel"_ns);
+      mOwner->mRespondWithPromiseHolder.Reject(
+          CancelInterceptionArgs(
+              NS_ERROR_INTERCEPTION_FAILED,
+              FetchEventTimeStamps(mOwner->mFetchHandlerStart,
+                                   mOwner->mFetchHandlerFinish)),
+          __func__);
+    }
+  }
+
+  // This function steals the error message from a ErrorResult.
+  void SetCancelErrorResult(JSContext* aCx, ErrorResult& aRv) {
+    MOZ_DIAGNOSTIC_ASSERT(aRv.Failed());
+    MOZ_DIAGNOSTIC_ASSERT(!JS_IsExceptionPending(aCx));
+
+    // Storing the error as exception in the JSContext.
+    if (!aRv.MaybeSetPendingException(aCx)) {
+      return;
+    }
+
+    MOZ_ASSERT(!aRv.Failed());
+
+    // Let's take the pending exception.
+    JS::ExceptionStack exnStack(aCx);
+    if (!JS::StealPendingExceptionStack(aCx, &exnStack)) {
+      return;
+    }
+
+    // Converting the exception in a JS::ErrorReportBuilder.
+    JS::ErrorReportBuilder report(aCx);
+    if (!report.init(aCx, exnStack, JS::ErrorReportBuilder::WithSideEffects)) {
+      JS_ClearPendingException(aCx);
+      return;
+    }
+
+    MOZ_ASSERT(mOwner);
+    MOZ_ASSERT(mMessageName.EqualsLiteral("InterceptionFailedWithURL"));
+    MOZ_ASSERT(mParams.Length() == 1);
+
+    // Let's store the error message here.
+    mMessageName.Assign(report.toStringResult().c_str());
+    mParams.Clear();
+  }
+
+  template <typename... Params>
+  void SetCancelMessage(const nsACString& aMessageName, Params&&... aParams) {
+    MOZ_ASSERT(mOwner);
+    MOZ_ASSERT(mMessageName.EqualsLiteral("InterceptionFailedWithURL"));
+    MOZ_ASSERT(mParams.Length() == 1);
+    mMessageName = aMessageName;
+    mParams.Clear();
+    StringArrayAppender::Append(mParams, sizeof...(Params),
+                                std::forward<Params>(aParams)...);
+  }
+
+  template <typename... Params>
+  void SetCancelMessageAndLocation(const nsACString& aSourceSpec,
+                                   uint32_t aLine, uint32_t aColumn,
+                                   const nsACString& aMessageName,
+                                   Params&&... aParams) {
+    MOZ_ASSERT(mOwner);
+    MOZ_ASSERT(mMessageName.EqualsLiteral("InterceptionFailedWithURL"));
+    MOZ_ASSERT(mParams.Length() == 1);
+
+    mSourceSpec = aSourceSpec;
+    mLine = aLine;
+    mColumn = aColumn;
+
+    mMessageName = aMessageName;
+    mParams.Clear();
+    StringArrayAppender::Append(mParams, sizeof...(Params),
+                                std::forward<Params>(aParams)...);
+  }
+
+  void Reset() { mOwner = nullptr; }
+
+ private:
+  FetchEventOp* MOZ_NON_OWNING_REF mOwner;
+  nsCString mSourceSpec;
+  uint32_t mLine;
+  uint32_t mColumn;
+  nsCString mMessageName;
+  nsTArray<nsString> mParams;
+};
+
+NS_IMPL_ISUPPORTS0(FetchEventOp)
+
+void FetchEventOp::SetActor(RefPtr<FetchEventOpProxyChild> aActor) {
+  MOZ_ASSERT(RemoteWorkerService::Thread()->IsOnCurrentThread());
+  MOZ_ASSERT(!Started());
+  MOZ_ASSERT(!mActor);
+
+  mActor = std::move(aActor);
+}
+
+void FetchEventOp::RevokeActor(FetchEventOpProxyChild* aActor) {
+  MOZ_ASSERT(aActor);
+  MOZ_ASSERT_IF(mActor, mActor == aActor);
+
+  mActor = nullptr;
+}
+
+RefPtr<FetchEventRespondWithPromise> FetchEventOp::GetRespondWithPromise() {
+  MOZ_ASSERT(RemoteWorkerService::Thread()->IsOnCurrentThread());
+  MOZ_ASSERT(!Started());
+  MOZ_ASSERT(mRespondWithPromiseHolder.IsEmpty());
+
+  return mRespondWithPromiseHolder.Ensure(__func__);
+}
+
+void FetchEventOp::RespondWithCalledAt(const nsCString& aRespondWithScriptSpec,
+                                       uint32_t aRespondWithLineNumber,
+                                       uint32_t aRespondWithColumnNumber) {
+  MOZ_ASSERT(IsCurrentThreadRunningWorker());
+  MOZ_ASSERT(!mRespondWithClosure);
+
+  mRespondWithClosure.emplace(aRespondWithScriptSpec, aRespondWithLineNumber,
+                              aRespondWithColumnNumber);
+}
+
+void FetchEventOp::ReportCanceled(const nsCString& aPreventDefaultScriptSpec,
+                                  uint32_t aPreventDefaultLineNumber,
+                                  uint32_t aPreventDefaultColumnNumber) {
+  MOZ_ASSERT(IsCurrentThreadRunningWorker());
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+  nsString requestURL;
+  GetRequestURL(requestURL);
+
+  AsyncLog(aPreventDefaultScriptSpec, aPreventDefaultLineNumber,
+           aPreventDefaultColumnNumber, "InterceptionCanceledWithURL"_ns,
+           {std::move(requestURL)});
+}
+
+FetchEventOp::~FetchEventOp() {
+  mRespondWithPromiseHolder.RejectIfExists(
+      CancelInterceptionArgs(
+          NS_ERROR_DOM_ABORT_ERR,
+          FetchEventTimeStamps(mFetchHandlerStart, mFetchHandlerFinish)),
+      __func__);
+}
+
+void FetchEventOp::RejectAll(nsresult aStatus) {
+  MOZ_ASSERT(!mRespondWithPromiseHolder.IsEmpty());
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+  if (mFetchHandlerStart.IsNull()) {
+    mFetchHandlerStart = TimeStamp::Now();
+  }
+  if (mFetchHandlerFinish.IsNull()) {
+    mFetchHandlerFinish = TimeStamp::Now();
+  }
+
+  mRespondWithPromiseHolder.Reject(
+      CancelInterceptionArgs(
+          aStatus,
+          FetchEventTimeStamps(mFetchHandlerStart, mFetchHandlerFinish)),
+      __func__);
+  mPromiseHolder.Reject(aStatus, __func__);
+}
+
+void FetchEventOp::FinishedWithResult(ExtendableEventResult aResult) {
+  MOZ_ASSERT(IsCurrentThreadRunningWorker());
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+  MOZ_ASSERT(!mResult);
+
+  mResult.emplace(aResult);
+
+  /**
+   * This should only return early if neither waitUntil() nor respondWith()
+   * are called. The early return is so that mRespondWithPromiseHolder has a
+   * chance to settle before mPromiseHolder does.
+   */
+  if (!mPostDispatchChecksDone) {
+    return;
+  }
+
+  MaybeFinished();
+}
+
+void FetchEventOp::MaybeFinished() {
+  MOZ_ASSERT(IsCurrentThreadRunningWorker());
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+  if (mResult) {
+    // It's possible that mRespondWithPromiseHolder wasn't settled. That happens
+    // if the worker was terminated before the respondWith promise settled.
+
+    mHandled = nullptr;
+    mPreloadResponse = nullptr;
+    mPreloadResponseAvailablePromiseRequestHolder.DisconnectIfExists();
+    mPreloadResponseTimingPromiseRequestHolder.DisconnectIfExists();
+    mPreloadResponseEndPromiseRequestHolder.DisconnectIfExists();
+
+    ServiceWorkerFetchEventOpResult result(
+        mResult.value() == Resolved ? NS_OK : NS_ERROR_FAILURE);
+
+    mPromiseHolder.Resolve(result, __func__);
+  }
+}
+
+bool FetchEventOp::Exec(JSContext* aCx, WorkerPrivate* aWorkerPrivate) {
+  aWorkerPrivate->AssertIsOnWorkerThread();
+  MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+  MOZ_ASSERT(!mRespondWithPromiseHolder.IsEmpty());
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+  nsresult rv = DispatchFetchEvent(aCx, aWorkerPrivate);
+
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    RejectAll(rv);
+  }
+
+  return NS_SUCCEEDED(rv);
+}
+
+void FetchEventOp::AsyncLog(const nsCString& aMessageName,
+                            nsTArray<nsString> aParams) {
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+  MOZ_ASSERT(mRespondWithClosure);
+
+  const FetchEventRespondWithClosure& closure = mRespondWithClosure.ref();
+
+  AsyncLog(closure.respondWithScriptSpec(), closure.respondWithLineNumber(),
+           closure.respondWithColumnNumber(), aMessageName, std::move(aParams));
+}
+
+void FetchEventOp::AsyncLog(const nsCString& aScriptSpec, uint32_t aLineNumber,
+                            uint32_t aColumnNumber,
+                            const nsCString& aMessageName,
+                            nsTArray<nsString> aParams) {
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+  // Capture `this` because FetchEventOpProxyChild (mActor) is not thread
+  // safe, so an AddRef from RefPtr<FetchEventOpProxyChild>'s constructor will
+  // assert.
+  RefPtr<FetchEventOp> self = this;
+
+  nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
+      __func__, [self = std::move(self), spec = aScriptSpec, line = aLineNumber,
+                 column = aColumnNumber, messageName = aMessageName,
+                 params = std::move(aParams)] {
+        if (NS_WARN_IF(!self->mActor)) {
+          return;
+        }
+
+        Unused << self->mActor->SendAsyncLog(spec, line, column, messageName,
+                                             params);
+      });
+
+  MOZ_ALWAYS_SUCCEEDS(
+      RemoteWorkerService::Thread()->Dispatch(r.forget(), NS_DISPATCH_NORMAL));
+}
+
+void FetchEventOp::GetRequestURL(nsAString& aOutRequestURL) {
+  nsTArray<nsCString>& urls =
+      mArgs.get_ParentToChildServiceWorkerFetchEventOpArgs()
+          .common()
+          .internalRequest()
+          .urlList();
+  MOZ_ASSERT(!urls.IsEmpty());
+
+  CopyUTF8toUTF16(urls.LastElement(), aOutRequestURL);
+}
+
+void FetchEventOp::ResolvedCallback(JSContext* aCx,
+                                    JS::Handle<JS::Value> aValue,
+                                    ErrorResult& aRv) {
+  MOZ_ASSERT(IsCurrentThreadRunningWorker());
+  MOZ_ASSERT(mRespondWithClosure);
+  MOZ_ASSERT(!mRespondWithPromiseHolder.IsEmpty());
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+  mFetchHandlerFinish = TimeStamp::Now();
+
+  nsAutoString requestURL;
+  GetRequestURL(requestURL);
+
+  AutoCancel autoCancel(this);
+
+  if (!aValue.isObject()) {
+    NS_WARNING(
+        "FetchEvent::RespondWith was passed a promise resolved to a "
+        "non-Object "
+        "value");
+
+    nsCString sourceSpec;
+    uint32_t line = 0;
+    uint32_t column = 0;
+    nsString valueString;
+    nsContentUtils::ExtractErrorValues(aCx, aValue, sourceSpec, &line, &column,
+                                       valueString);
+
+    autoCancel.SetCancelMessageAndLocation(sourceSpec, line, column,
+                                           "InterceptedNonResponseWithURL"_ns,
+                                           requestURL, valueString);
+    return;
+  }
+
+  RefPtr<Response> response;
+  nsresult rv = UNWRAP_OBJECT(Response, &aValue.toObject(), response);
+  if (NS_FAILED(rv)) {
+    nsCString sourceSpec;
+    uint32_t line = 0;
+    uint32_t column = 0;
+    nsString valueString;
+    nsContentUtils::ExtractErrorValues(aCx, aValue, sourceSpec, &line, &column,
+                                       valueString);
+
+    autoCancel.SetCancelMessageAndLocation(sourceSpec, line, column,
+                                           "InterceptedNonResponseWithURL"_ns,
+                                           requestURL, valueString);
+    return;
+  }
+
+  WorkerPrivate* worker = GetCurrentThreadWorkerPrivate();
+  MOZ_ASSERT(worker);
+  worker->AssertIsOnWorkerThread();
+
+  // Section "HTTP Fetch", step 3.3:
+  //  If one of the following conditions is true, return a network error:
+  //    * response's type is "error".
+  //    * request's mode is not "no-cors" and response's type is "opaque".
+  //    * request's redirect mode is not "manual" and response's type is
+  //      "opaqueredirect".
+  //    * request's redirect mode is not "follow" and response's url list
+  //      has more than one item.
+
+  if (response->Type() == ResponseType::Error) {
+    autoCancel.SetCancelMessage("InterceptedErrorResponseWithURL"_ns,
+                                requestURL);
+    return;
+  }
+
+  const ParentToChildServiceWorkerFetchEventOpArgs& args =
+      mArgs.get_ParentToChildServiceWorkerFetchEventOpArgs();
+  const RequestMode requestMode = args.common().internalRequest().requestMode();
+
+  if (response->Type() == ResponseType::Opaque &&
+      requestMode != RequestMode::No_cors) {
+    NS_ConvertASCIItoUTF16 modeString(
+        RequestModeValues::GetString(requestMode));
+
+    nsAutoString requestURL;
+    GetRequestURL(requestURL);
+
+    autoCancel.SetCancelMessage("BadOpaqueInterceptionRequestModeWithURL"_ns,
+                                requestURL, modeString);
+    return;
+  }
+
+  const RequestRedirect requestRedirectMode =
+      args.common().internalRequest().requestRedirect();
+
+  if (requestRedirectMode != RequestRedirect::Manual &&
+      response->Type() == ResponseType::Opaqueredirect) {
+    autoCancel.SetCancelMessage("BadOpaqueRedirectInterceptionWithURL"_ns,
+                                requestURL);
+    return;
+  }
+
+  if (requestRedirectMode != RequestRedirect::Follow &&
+      response->Redirected()) {
+    autoCancel.SetCancelMessage("BadRedirectModeInterceptionWithURL"_ns,
+                                requestURL);
+    return;
+  }
+
+  if (NS_WARN_IF(response->BodyUsed())) {
+    autoCancel.SetCancelMessage("InterceptedUsedResponseWithURL"_ns,
+                                requestURL);
+    return;
+  }
+
+  SafeRefPtr<InternalResponse> ir = response->GetInternalResponse();
+  if (NS_WARN_IF(!ir)) {
+    return;
+  }
+
+  // An extra safety check to make sure our invariant that opaque and cors
+  // responses always have a URL does not break.
+  if (NS_WARN_IF((response->Type() == ResponseType::Opaque ||
+                  response->Type() == ResponseType::Cors) &&
+                 ir->GetUnfilteredURL().IsEmpty())) {
+    MOZ_DIAGNOSTIC_ASSERT(false, "Cors or opaque Response without a URL");
+    return;
+  }
+
+  if (requestMode == RequestMode::Same_origin &&
+      response->Type() == ResponseType::Cors) {
+    Telemetry::ScalarAdd(Telemetry::ScalarID::SW_CORS_RES_FOR_SO_REQ_COUNT, 1);
+
+    // XXXtt: Will have a pref to enable the quirk response in bug 1419684.
+    // The variadic template provided by StringArrayAppender requires exactly
+    // an nsString.
+    NS_ConvertUTF8toUTF16 responseURL(ir->GetUnfilteredURL());
+    autoCancel.SetCancelMessage("CorsResponseForSameOriginRequest"_ns,
+                                requestURL, responseURL);
+    return;
+  }
+
+  nsCOMPtr<nsIInputStream> body;
+  ir->GetUnfilteredBody(getter_AddRefs(body));
+  // Errors and redirects may not have a body.
+  if (body) {
+    ErrorResult error;
+    response->SetBodyUsed(aCx, error);
+    error.WouldReportJSException();
+    if (NS_WARN_IF(error.Failed())) {
+      autoCancel.SetCancelErrorResult(aCx, error);
+      return;
+    }
+  }
+
+  if (!ir->GetChannelInfo().IsInitialized()) {
+    // This is a synthetic response (I think and hope so).
+    ir->InitChannelInfo(worker->GetChannelInfo());
+  }
+
+  autoCancel.Reset();
+
+  // https://w3c.github.io/ServiceWorker/#on-fetch-request-algorithm Step 26: If
+  // eventHandled is not null, then resolve eventHandled.
+  //
+  // mRespondWithPromiseHolder will resolve a MozPromise that will resolve on
+  // the worker owner's thread, so it's fine to resolve the mHandled promise now
+  // because content will not interfere with respondWith getting the Response to
+  // where it's going.
+  mHandled->MaybeResolveWithUndefined();
+  mRespondWithPromiseHolder.Resolve(
+      FetchEventRespondWithResult(std::make_tuple(
+          std::move(ir), mRespondWithClosure.ref(),
+          FetchEventTimeStamps(mFetchHandlerStart, mFetchHandlerFinish))),
+      __func__);
+}
+
+void FetchEventOp::RejectedCallback(JSContext* aCx,
+                                    JS::Handle<JS::Value> aValue,
+                                    ErrorResult& aRv) {
+  MOZ_ASSERT(IsCurrentThreadRunningWorker());
+  MOZ_ASSERT(mRespondWithClosure);
+  MOZ_ASSERT(!mRespondWithPromiseHolder.IsEmpty());
+  MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+  mFetchHandlerFinish = TimeStamp::Now();
+
+  FetchEventRespondWithClosure& closure = mRespondWithClosure.ref();
+
+  nsCString sourceSpec = closure.respondWithScriptSpec();
+  uint32_t line = closure.respondWithLineNumber();
+  uint32_t column = closure.respondWithColumnNumber();
+  nsString valueString;
+
+  nsContentUtils::ExtractErrorValues(aCx, aValue, sourceSpec, &line, &column,
+                                     valueString);
+
+  nsString requestURL;
+  GetRequestURL(requestURL);
+
+  AsyncLog(sourceSpec, line, column, "InterceptionRejectedResponseWithURL"_ns,
+           {std::move(requestURL), valueString});
+
+  // https://w3c.github.io/ServiceWorker/#on-fetch-request-algorithm Step 25.1:
+  // If eventHandled is not null, then reject eventHandled with a "NetworkError"
+  // DOMException in workerRealm.
+  mHandled->MaybeRejectWithNetworkError(
+      "FetchEvent.respondWith() Promise rejected"_ns);
+  mRespondWithPromiseHolder.Resolve(
+      FetchEventRespondWithResult(CancelInterceptionArgs(
+          NS_ERROR_INTERCEPTION_FAILED,
+          FetchEventTimeStamps(mFetchHandlerStart, mFetchHandlerFinish))),
+      __func__);
+}
+
+nsresult FetchEventOp::DispatchFetchEvent(JSContext* aCx,
+                                          WorkerPrivate* aWorkerPrivate) {
+  MOZ_ASSERT(aCx);
+  MOZ_ASSERT(aWorkerPrivate);
+  aWorkerPrivate->AssertIsOnWorkerThread();
+  MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+
+  ParentToChildServiceWorkerFetchEventOpArgs& args =
+      mArgs.get_ParentToChildServiceWorkerFetchEventOpArgs();
+
+  /**
+   * Testing: Failure injection.
+   *
+   * There are a number of different ways that this fetch event could have
+   * failed that would result in cancellation.  This injection point helps
+   * simulate them without worrying about shifting implementation details with
+   * full fidelity reproductions of current scenarios.
+   *
+   * Broadly speaking, we expect fetch event scenarios to fail because of:
+   * - Script load failure, which results in the CompileScriptRunnable closing
+   *   the worker and thereby cancelling all pending operations, including this
+   *   fetch.  The `ServiceWorkerOp::Cancel` impl just calls
+   *   RejectAll(NS_ERROR_DOM_ABORT_ERR) which we are able to approximate by
+   *   returning the same nsresult here, as our caller also calls RejectAll.
+   *   (And timing-wise, this rejection will happen in the correct sequence.)
+   * - An exception gets thrown in the processing of the promise that was passed
+   *   to respondWith and it ends up rejecting.  The rejection will be converted
+   *   by `FetchEventOp::RejectedCallback` into a cancellation with
+   *   NS_ERROR_INTERCEPTION_FAILED, and by returning that here we approximate
+   *   that failure mode.
+   */
+  if (NS_FAILED(args.common().testingInjectCancellation())) {
+    return args.common().testingInjectCancellation();
+  }
+
+  /**
+   * Step 1: get the InternalRequest. The InternalRequest can't be constructed
+   * here from mArgs because the IPCStream has to be deserialized on the
+   * thread receiving the ServiceWorkerFetchEventOpArgs.
+   * FetchEventOpProxyChild will have already deserialized the stream on the
+   * correct thread before creating this op, so we can take its saved
+   * InternalRequest.
+   */
+  SafeRefPtr<InternalRequest> internalRequest =
+      mActor->ExtractInternalRequest();
+
+  /**
+   * Step 2: get the worker's global object
+   */
+  GlobalObject globalObject(aCx, aWorkerPrivate->GlobalScope()->GetWrapper());
+  nsCOMPtr<nsIGlobalObject> globalObjectAsSupports =
+      do_QueryInterface(globalObject.GetAsSupports());
+  if (NS_WARN_IF(!globalObjectAsSupports)) {
+    return NS_ERROR_DOM_INVALID_STATE_ERR;
+  }
+
+  /**
+   * Step 3: create the public DOM Request object
+   * TODO: this Request object should be created with an AbortSignal object
+   * which should be aborted if the loading is aborted. See but 1394102.
+   */
+  RefPtr<Request> request =
+      new Request(globalObjectAsSupports, internalRequest.clonePtr(), nullptr);
+  MOZ_ASSERT_IF(internalRequest->IsNavigationRequest(),
+                request->Redirect() == RequestRedirect::Manual);
+
+  /**
+   * Step 4a: create the FetchEventInit
+   */
+  RootedDictionary<FetchEventInit> fetchEventInit(aCx);
+  fetchEventInit.mRequest = request;
+  fetchEventInit.mBubbles = false;
+  fetchEventInit.mCancelable = true;
+
+  /**
+   * TODO: only expose the FetchEvent.clientId on subresource requests for
+   * now. Once we implement .targetClientId we can then start exposing
+   * .clientId on non-subresource requests as well.  See bug 1487534.
+   */
+  if (!args.common().clientId().IsEmpty() &&
+      !internalRequest->IsNavigationRequest()) {
+    fetchEventInit.mClientId = args.common().clientId();
+  }
+
+  /*
+   * https://w3c.github.io/ServiceWorker/#on-fetch-request-algorithm
+   *
+   * "If request is a non-subresource request and request’s
+   * destination is not "report", initialize e’s resultingClientId attribute
+   * to reservedClient’s [resultingClient's] id, and to the empty string
+   * otherwise." (Step 18.8)
+   */
+  if (!args.common().resultingClientId().IsEmpty() &&
+      args.common().isNonSubresourceRequest() &&
+      internalRequest->Destination() != RequestDestination::Report) {
+    fetchEventInit.mResultingClientId = args.common().resultingClientId();
+  }
+
+  /**
+   * Step 4b: create the FetchEvent
+   */
+  RefPtr<FetchEvent> fetchEvent =
+      FetchEvent::Constructor(globalObject, u"fetch"_ns, fetchEventInit);
+  fetchEvent->SetTrusted(true);
+  fetchEvent->PostInit(args.common().workerScriptSpec(), this);
+  mHandled = fetchEvent->Handled();
+  mPreloadResponse = fetchEvent->PreloadResponse();
+
+  if (args.common().preloadNavigation()) {
+    RefPtr<FetchEventPreloadResponseAvailablePromise> preloadResponsePromise =
+        mActor->GetPreloadResponseAvailablePromise();
+    MOZ_ASSERT(preloadResponsePromise);
+
+    // If preloadResponsePromise has already settled then this callback will get
+    // run synchronously here.
+    RefPtr<FetchEventOp> self = this;
+    preloadResponsePromise
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [self, globalObjectAsSupports](
+                SafeRefPtr<InternalResponse>&& aPreloadResponse) {
+              self->mPreloadResponse->MaybeResolve(
+                  MakeRefPtr<Response>(globalObjectAsSupports,
+                                       std::move(aPreloadResponse), nullptr));
+              self->mPreloadResponseAvailablePromiseRequestHolder.Complete();
+            },
+            [self](int) {
+              self->mPreloadResponseAvailablePromiseRequestHolder.Complete();
+            })
+        ->Track(mPreloadResponseAvailablePromiseRequestHolder);
+
+    RefPtr<PerformanceStorage> performanceStorage =
+        aWorkerPrivate->GetPerformanceStorage();
+
+    RefPtr<FetchEventPreloadResponseTimingPromise>
+        preloadResponseTimingPromise =
+            mActor->GetPreloadResponseTimingPromise();
+    MOZ_ASSERT(preloadResponseTimingPromise);
+    preloadResponseTimingPromise
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [self, performanceStorage,
+             globalObjectAsSupports](ResponseTiming&& aTiming) {
+              if (performanceStorage && !aTiming.entryName().IsEmpty() &&
+                  aTiming.initiatorType().Equals(u"navigation"_ns)) {
+                performanceStorage->AddEntry(
+                    aTiming.entryName(), aTiming.initiatorType(),
+                    MakeUnique<PerformanceTimingData>(aTiming.timingData()));
+              }
+              self->mPreloadResponseTimingPromiseRequestHolder.Complete();
+            },
+            [self](int) {
+              self->mPreloadResponseTimingPromiseRequestHolder.Complete();
+            })
+        ->Track(mPreloadResponseTimingPromiseRequestHolder);
+
+    RefPtr<FetchEventPreloadResponseEndPromise> preloadResponseEndPromise =
+        mActor->GetPreloadResponseEndPromise();
+    MOZ_ASSERT(preloadResponseEndPromise);
+    preloadResponseEndPromise
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [self, globalObjectAsSupports](ResponseEndArgs&& aArgs) {
+              if (aArgs.endReason() == FetchDriverObserver::eAborted) {
+                self->mPreloadResponse->MaybeReject(NS_ERROR_DOM_ABORT_ERR);
+              }
+              self->mPreloadResponseEndPromiseRequestHolder.Complete();
+            },
+            [self](int) {
+              self->mPreloadResponseEndPromiseRequestHolder.Complete();
+            })
+        ->Track(mPreloadResponseEndPromiseRequestHolder);
+  } else {
+    // preload navigation is disabled, resolved preload response promise with
+    // undefined as default behavior.
+    mPreloadResponse->MaybeResolveWithUndefined();
+  }
+
+  mFetchHandlerStart = TimeStamp::Now();
+
+  /**
+   * Step 5: Dispatch the FetchEvent to the worker's global object
+   */
+  nsresult rv = DispatchExtendableEventOnWorkerScope(
+      aCx, aWorkerPrivate->GlobalScope(), fetchEvent, this);
+  bool dispatchFailed = NS_FAILED(rv) && rv != NS_ERROR_XPC_JS_THREW_EXCEPTION;
+
+  if (NS_WARN_IF(dispatchFailed)) {
+    mHandled = nullptr;
+    mPreloadResponse = nullptr;
+    return rv;
+  }
+
+  /**
+   * At this point, there are 4 (legal) scenarios:
+   *
+   * 1) If neither waitUntil() nor respondWith() are called,
+   * DispatchExtendableEventOnWorkerScope() will have already called
+   * FinishedWithResult(), but this call will have recorded the result
+   * (mResult) and returned early so that mRespondWithPromiseHolder can be
+   * settled first. mRespondWithPromiseHolder will be settled below, followed
+   * by a call to MaybeFinished() which settles mPromiseHolder.
+   *
+   * 2) If waitUntil() is called at least once, and respondWith() is not
+   * called, DispatchExtendableEventOnWorkerScope() will NOT have called
+   * FinishedWithResult(). We'll settle mRespondWithPromiseHolder first, and
+   * at some point in the future when the last waitUntil() promise settles,
+   * FinishedWithResult() will be called, settling mPromiseHolder.
+   *
+   * 3) If waitUntil() is not called, and respondWith() is called,
+   * DispatchExtendableEventOnWorkerScope() will NOT have called
+   * FinishedWithResult(). We can also guarantee that
+   * mRespondWithPromiseHolder will be settled before mPromiseHolder, due to
+   * the Promise::AppendNativeHandler() call ordering in
+   * FetchEvent::RespondWith().
+   *
+   * 4) If waitUntil() is called at least once, and respondWith() is also
+   * called, the effect is similar to scenario 3), with the most imporant
+   * property being mRespondWithPromiseHolder settling before mPromiseHolder.
+   *
+   * Note that if mPromiseHolder is settled before mRespondWithPromiseHolder,
+   * FetchEventOpChild will cancel the interception.
+   */
+  if (!fetchEvent->WaitToRespond()) {
+    MOZ_ASSERT(!mRespondWithPromiseHolder.IsEmpty());
+    MOZ_ASSERT(!aWorkerPrivate->UsesSystemPrincipal(),
+               "We don't support system-principal serviceworkers");
+
+    mFetchHandlerFinish = TimeStamp::Now();
+
+    if (fetchEvent->DefaultPrevented(CallerType::NonSystem)) {
+      // https://w3c.github.io/ServiceWorker/#on-fetch-request-algorithm
+      // Step 24.1.1: If eventHandled is not null, then reject eventHandled with
+      // a "NetworkError" DOMException in workerRealm.
+      mHandled->MaybeRejectWithNetworkError(
+          "FetchEvent.preventDefault() called"_ns);
+      mRespondWithPromiseHolder.Resolve(
+          FetchEventRespondWithResult(CancelInterceptionArgs(
+              NS_ERROR_INTERCEPTION_FAILED,
+              FetchEventTimeStamps(mFetchHandlerStart, mFetchHandlerFinish))),
+          __func__);
+    } else {
+      // https://w3c.github.io/ServiceWorker/#on-fetch-request-algorithm
+      // Step 24.2: If eventHandled is not null, then resolve eventHandled.
+      mHandled->MaybeResolveWithUndefined();
+      mRespondWithPromiseHolder.Resolve(
+          FetchEventRespondWithResult(ResetInterceptionArgs(
+              FetchEventTimeStamps(mFetchHandlerStart, mFetchHandlerFinish))),
+          __func__);
+    }
+  } else {
+    MOZ_ASSERT(mRespondWithClosure);
+  }
+
+  mPostDispatchChecksDone = true;
+  MaybeFinished();
+
+  return NS_OK;
+}
+
+class ExtensionAPIEventOp final : public ServiceWorkerOp {
+  using ServiceWorkerOp::ServiceWorkerOp;
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ExtensionAPIEventOp, override)
+
+ private:
+  ~ExtensionAPIEventOp() = default;
+
+  bool Exec(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+    MOZ_ASSERT(aWorkerPrivate->IsServiceWorker());
+    MOZ_ASSERT(aWorkerPrivate->ExtensionAPIAllowed());
+    MOZ_ASSERT(!mPromiseHolder.IsEmpty());
+
+    ServiceWorkerExtensionAPIEventOpArgs& args =
+        mArgs.get_ServiceWorkerExtensionAPIEventOpArgs();
+
+    ServiceWorkerExtensionAPIEventOpResult result;
+    result.extensionAPIEventListenerWasAdded() = false;
+
+    if (aWorkerPrivate->WorkerScriptExecutedSuccessfully()) {
+      GlobalObject globalObj(aCx, aWorkerPrivate->GlobalScope()->GetWrapper());
+      RefPtr<ServiceWorkerGlobalScope> scope;
+      UNWRAP_OBJECT(ServiceWorkerGlobalScope, globalObj.Get(), scope);
+      SafeRefPtr<extensions::ExtensionBrowser> extensionAPI =
+          scope->AcquireExtensionBrowser();
+      if (!extensionAPI) {
+        // If the worker script did never access the WebExtension APIs
+        // then we can return earlier, no event listener could have been added.
+        mPromiseHolder.Resolve(result, __func__);
+        return true;
+      }
+      // Check if a listener has been subscribed on the expected WebExtensions
+      // API event.
+      bool hasWakeupListener = extensionAPI->HasWakeupEventListener(
+          args.apiNamespace(), args.apiEventName());
+      result.extensionAPIEventListenerWasAdded() = hasWakeupListener;
+      mPromiseHolder.Resolve(result, __func__);
+    } else {
+      mPromiseHolder.Resolve(result, __func__);
+    }
+
+    return true;
+  }
+};
+
+/* static */ already_AddRefed<ServiceWorkerOp> ServiceWorkerOp::Create(
+    ServiceWorkerOpArgs&& aArgs,
+    std::function<void(const ServiceWorkerOpResult&)>&& aCallback) {
+  MOZ_ASSERT(RemoteWorkerService::Thread()->IsOnCurrentThread());
+
+  RefPtr<ServiceWorkerOp> op;
+
+  switch (aArgs.type()) {
+    case ServiceWorkerOpArgs::TServiceWorkerCheckScriptEvaluationOpArgs:
+      op = MakeRefPtr<CheckScriptEvaluationOp>(std::move(aArgs),
+                                               std::move(aCallback));
+      break;
+    case ServiceWorkerOpArgs::TServiceWorkerUpdateStateOpArgs:
+      op = MakeRefPtr<UpdateServiceWorkerStateOp>(std::move(aArgs),
+                                                  std::move(aCallback));
+      break;
+    case ServiceWorkerOpArgs::TServiceWorkerTerminateWorkerOpArgs:
+      op = MakeRefPtr<TerminateServiceWorkerOp>(std::move(aArgs),
+                                                std::move(aCallback));
+      break;
+    case ServiceWorkerOpArgs::TServiceWorkerLifeCycleEventOpArgs:
+      op = MakeRefPtr<LifeCycleEventOp>(std::move(aArgs), std::move(aCallback));
+      break;
+    case ServiceWorkerOpArgs::TServiceWorkerPushEventOpArgs:
+      op = MakeRefPtr<PushEventOp>(std::move(aArgs), std::move(aCallback));
+      break;
+    case ServiceWorkerOpArgs::TServiceWorkerPushSubscriptionChangeEventOpArgs:
+      op = MakeRefPtr<PushSubscriptionChangeEventOp>(std::move(aArgs),
+                                                     std::move(aCallback));
+      break;
+    case ServiceWorkerOpArgs::TServiceWorkerNotificationEventOpArgs:
+      op = MakeRefPtr<NotificationEventOp>(std::move(aArgs),
+                                           std::move(aCallback));
+      break;
+    case ServiceWorkerOpArgs::TServiceWorkerMessageEventOpArgs:
+      op = MakeRefPtr<MessageEventOp>(std::move(aArgs), std::move(aCallback));
+      break;
+    case ServiceWorkerOpArgs::TParentToChildServiceWorkerFetchEventOpArgs:
+      op = MakeRefPtr<FetchEventOp>(std::move(aArgs), std::move(aCallback));
+      break;
+    case ServiceWorkerOpArgs::TServiceWorkerExtensionAPIEventOpArgs:
+      op = MakeRefPtr<ExtensionAPIEventOp>(std::move(aArgs),
+                                           std::move(aCallback));
+      break;
+    default:
+      MOZ_CRASH("Unknown Service Worker operation!");
+      return nullptr;
+  }
+
+  return op.forget();
+}
+
+}  // namespace mozilla::dom