gecko-dev/dom/broadcastchannel/BroadcastChannelChild.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 "BroadcastChannelChild.h"
#include "BroadcastChannel.h"
#include "jsapi.h"
#include "mozilla/dom/ipc/BlobChild.h"
#include "mozilla/dom/File.h"
#include "mozilla/dom/MessageEvent.h"
#include "mozilla/dom/MessageEventBinding.h"
#include "mozilla/dom/WorkerPrivate.h"
#include "mozilla/dom/WorkerScope.h"
#include "mozilla/dom/ScriptSettings.h"
#include "mozilla/ipc/PBackgroundChild.h"
#include "mozilla/dom/ipc/StructuredCloneData.h"
#include "WorkerPrivate.h"

namespace mozilla {

using namespace ipc;

namespace dom {

using namespace workers;

BroadcastChannelChild::BroadcastChannelChild(const nsACString& aOrigin)
  : mActorDestroyed(false)
{
  CopyUTF8toUTF16(aOrigin, mOrigin);
}

BroadcastChannelChild::~BroadcastChannelChild()
{
  MOZ_ASSERT(!mBC);
}

bool
BroadcastChannelChild::RecvNotify(const ClonedMessageData& aData)
{
  // Make sure to retrieve all blobs from the message before returning to avoid
  // leaking their actors.
  nsTArray<nsRefPtr<BlobImpl>> blobs;
  if (!aData.blobsChild().IsEmpty()) {
    blobs.SetCapacity(aData.blobsChild().Length());

    for (uint32_t i = 0, len = aData.blobsChild().Length(); i < len; ++i) {
      nsRefPtr<BlobImpl> impl =
        static_cast<BlobChild*>(aData.blobsChild()[i])->GetBlobImpl();

      blobs.AppendElement(impl);
    }
  }

  nsCOMPtr<DOMEventTargetHelper> helper = mBC;
  nsCOMPtr<EventTarget> eventTarget = do_QueryInterface(helper);

  // This object has been already closed by content or is going to be deleted
  // soon. No notify is required.
  if (!eventTarget || mBC->IsClosed()) {
    return true;
  }

  // CheckInnerWindowCorrectness can be used also without a window when
  // BroadcastChannel is running in a worker. In this case, it's a NOP.
  if (NS_FAILED(mBC->CheckInnerWindowCorrectness())) {
    return true;
  }

  AutoJSAPI jsapi;
  nsCOMPtr<nsIGlobalObject> globalObject;

  if (NS_IsMainThread()) {
    globalObject = do_QueryInterface(mBC->GetParentObject());
  } else {
    WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
    MOZ_ASSERT(workerPrivate);
    globalObject = workerPrivate->GlobalScope();
  }

  if (!globalObject || !jsapi.Init(globalObject)) {
    NS_WARNING("Failed to initialize AutoJSAPI object.");
    return true;
  }

  ipc::StructuredCloneData cloneData;
  cloneData.BlobImpls().AppendElements(blobs);

  const SerializedStructuredCloneBuffer& buffer = aData.data();
  cloneData.UseExternalData(buffer.data, buffer.dataLength);

  JSContext* cx = jsapi.cx();
  JS::Rooted<JS::Value> value(cx, JS::NullValue());
  if (buffer.dataLength) {
    ErrorResult rv;
    cloneData.Read(cx, &value, rv);
    if (NS_WARN_IF(rv.Failed())) {
      return true;
    }
  }

  RootedDictionary<MessageEventInit> init(cx);
  init.mBubbles = false;
  init.mCancelable = false;
  init.mOrigin.Construct(mOrigin);
  init.mData = value;

  ErrorResult rv;
  nsRefPtr<MessageEvent> event =
    MessageEvent::Constructor(mBC, NS_LITERAL_STRING("message"), init, rv);
  if (rv.Failed()) {
    NS_WARNING("Failed to create a MessageEvent object.");
    return true;
  }

  event->SetTrusted(true);

  bool status;
  mBC->DispatchEvent(static_cast<Event*>(event.get()), &status);

  return true;
}

void
BroadcastChannelChild::ActorDestroy(ActorDestroyReason aWhy)
{
  mActorDestroyed = true;
}

} // namespace dom
} // namespace mozilla