gecko-dev/dom/workers/MessageEventRunnable.cpp

/* -*- 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 "MessageEventRunnable.h"

#include "mozilla/dom/MessageEvent.h"
#include "mozilla/dom/MessageEventBinding.h"
#include "mozilla/TimelineConsumers.h"
#include "mozilla/WorkerTimelineMarker.h"
#include "nsQueryObject.h"
#include "WorkerPrivate.h"
#include "WorkerScope.h"

namespace mozilla {
namespace dom {

MessageEventRunnable::MessageEventRunnable(WorkerPrivate* aWorkerPrivate,
                                           TargetAndBusyBehavior aBehavior)
  : WorkerDebuggeeRunnable(aWorkerPrivate, aBehavior)
  , StructuredCloneHolder(CloningSupported, TransferringSupported,
                          StructuredCloneScope::SameProcessDifferentThread)
{
}

bool
MessageEventRunnable::DispatchDOMEvent(JSContext* aCx,
                                       WorkerPrivate* aWorkerPrivate,
                                       DOMEventTargetHelper* aTarget,
                                       bool aIsMainThread)
{
  nsCOMPtr<nsIGlobalObject> parent = aTarget->GetParentObject();

  // For some workers without window, parent is null and we try to find it
  // from the JS Context.
  if (!parent) {
    JS::Rooted<JSObject*> globalObject(aCx, JS::CurrentGlobalOrNull(aCx));
    if (NS_WARN_IF(!globalObject)) {
      return false;
    }

    parent = xpc::NativeGlobal(globalObject);
    if (NS_WARN_IF(!parent)) {
      return false;
    }
  }

  MOZ_ASSERT(parent);

  JS::Rooted<JS::Value> messageData(aCx);
  IgnoredErrorResult rv;

  UniquePtr<AbstractTimelineMarker> start;
  UniquePtr<AbstractTimelineMarker> end;
  RefPtr<TimelineConsumers> timelines = TimelineConsumers::Get();
  bool isTimelineRecording = timelines && !timelines->IsEmpty();

  if (isTimelineRecording) {
    start = MakeUnique<WorkerTimelineMarker>(aIsMainThread
      ? ProfileTimelineWorkerOperationType::DeserializeDataOnMainThread
      : ProfileTimelineWorkerOperationType::DeserializeDataOffMainThread,
      MarkerTracingType::START);
  }

  Read(parent, aCx, &messageData, rv);

  if (isTimelineRecording) {
    end = MakeUnique<WorkerTimelineMarker>(aIsMainThread
      ? ProfileTimelineWorkerOperationType::DeserializeDataOnMainThread
      : ProfileTimelineWorkerOperationType::DeserializeDataOffMainThread,
      MarkerTracingType::END);
    timelines->AddMarkerForAllObservedDocShells(start);
    timelines->AddMarkerForAllObservedDocShells(end);
  }

  if (NS_WARN_IF(rv.Failed())) {
    DispatchError(aCx, aTarget);
    return false;
  }

  Sequence<OwningNonNull<MessagePort>> ports;
  if (!TakeTransferredPortsAsSequence(ports)) {
    DispatchError(aCx, aTarget);
    return false;
  }

  RefPtr<MessageEvent> event = new MessageEvent(aTarget, nullptr, nullptr);
  event->InitMessageEvent(nullptr,
                          NS_LITERAL_STRING("message"),
                          CanBubble::eNo,
                          Cancelable::eNo,
                          messageData,
                          EmptyString(),
                          EmptyString(),
                          nullptr,
                          ports);

  event->SetTrusted(true);

  aTarget->DispatchEvent(*event);

  return true;
}

bool
MessageEventRunnable::WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
{
  if (mBehavior == ParentThreadUnchangedBusyCount) {
    // Don't fire this event if the JS object has been disconnected from the
    // private object.
    if (!aWorkerPrivate->IsAcceptingEvents()) {
      return true;
    }

    // Once a window has frozen its workers, their
    // mMainThreadDebuggeeEventTargets should be paused, and their
    // WorkerDebuggeeRunnables should not be being executed. The same goes for
    // WorkerDebuggeeRunnables sent from child to parent workers, but since a
    // frozen parent worker runs only control runnables anyway, that is taken
    // care of naturally.
    MOZ_ASSERT(!aWorkerPrivate->IsFrozen());

    // Similarly for paused windows; all its workers should have been informed.
    // (Subworkers are unaffected by paused windows.)
    MOZ_ASSERT(!aWorkerPrivate->IsParentWindowPaused());

    aWorkerPrivate->AssertInnerWindowIsCorrect();

    return DispatchDOMEvent(aCx, aWorkerPrivate,
                            aWorkerPrivate->ParentEventTargetRef(),
                            !aWorkerPrivate->GetParent());
  }

  MOZ_ASSERT(aWorkerPrivate == GetWorkerPrivateFromContext(aCx));

  return DispatchDOMEvent(aCx, aWorkerPrivate, aWorkerPrivate->GlobalScope(),
                          false);
}

void
MessageEventRunnable::DispatchError(JSContext* aCx,
                                    DOMEventTargetHelper* aTarget)
{
  RootedDictionary<MessageEventInit> init(aCx);
  init.mBubbles = false;
  init.mCancelable = false;

  RefPtr<Event> event =
    MessageEvent::Constructor(aTarget, NS_LITERAL_STRING("messageerror"), init);
  event->SetTrusted(true);

  aTarget->DispatchEvent(*event);
}

} // dom namespace
} // mozilla namespace