ServiceWorkerCloneData.h

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/* -*- 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/. */

#ifndef mozilla_dom_ServiceWorkerCloneData_h__

#define mozilla_dom_ServiceWorkerCloneData_h__

#include "mozilla/Assertions.h"

#include "mozilla/dom/DOMTypes.h"

#include "mozilla/dom/ipc/StructuredCloneData.h"

#include "nsCOMPtr.h"

#include "nsISupports.h"

class nsISerialEventTarget;

namespace mozilla {

namespace ipc {

class PBackgroundChild;

class PBackgroundParent;

}  // namespace ipc

namespace dom {

class ClonedOrErrorMessageData;

// Helper class used to pack structured clone data so that it can be

// passed across thread and process boundaries.  Currently the raw

// StructuredCloneData and StructureCloneHolder APIs both make it

// difficult to meet this needs directly.  This helper class improves

// the situation by:

//

//  1. Provides a ref-counted version of StructuredCloneData.  We need

//     StructuredCloneData so we can serialize/deserialize across IPC.

//     The move constructor problems in StructuredCloneData (bug 1462676),

//     though, makes it hard to pass it around.  Passing a ref-counted

//     pointer addresses this problem.

//  2. Normally StructuredCloneData runs into problems if you try to move

//     it across thread boundaries because it releases its SharedJSAllocatedData

//     on the wrong thread.  This helper will correctly proxy release the

//     shared data on the correct thread.

//

// This helper class should really just be used to serialize on one thread

// and then move the reference across thread/process boundries to the

// target worker thread.  This class is not intended to support simultaneous

// read/write operations from different threads at the same time.

class ServiceWorkerCloneData final : public ipc::StructuredCloneData {

  nsCOMPtr<nsISerialEventTarget> mEventTarget;

  bool mIsErrorMessageData;

  ~ServiceWorkerCloneData();

 public:

  ServiceWorkerCloneData();

  bool BuildClonedMessageData(ClonedOrErrorMessageData& aClonedData);

  void CopyFromClonedMessageData(const ClonedOrErrorMessageData& aClonedData);

  void SetAsErrorMessageData();

  bool IsErrorMessageData() const;

  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ServiceWorkerCloneData)

};

}  // namespace dom

}  // namespace mozilla

#endif  // mozilla_dom_ServiceWorkerCloneData_h__