dom/serviceworkers/ServiceWorkerCloneData.h

   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 #ifndef mozilla_dom_ServiceWorkerCloneData_h__
   8 #define mozilla_dom_ServiceWorkerCloneData_h__
   9
  10 #include "mozilla/Assertions.h"
  11 #include "mozilla/dom/DOMTypes.h"
  12 #include "mozilla/dom/ipc/StructuredCloneData.h"
  13 #include "nsCOMPtr.h"
  14 #include "nsISupports.h"
  15
  16 class nsISerialEventTarget;
  17
  18 namespace mozilla {
  19 namespace ipc {
  20 class PBackgroundChild;
  21 class PBackgroundParent;
  22 }  // namespace ipc
  23
  24 namespace dom {
  25
  26 class ClonedOrErrorMessageData;
  27
  28 // Helper class used to pack structured clone data so that it can be
  29 // passed across thread and process boundaries.  Currently the raw
  30 // StructuredCloneData and StructureCloneHolder APIs both make it
  31 // difficult to meet this needs directly.  This helper class improves
  32 // the situation by:
  33 //
  34 //  1. Provides a ref-counted version of StructuredCloneData.  We need
  35 //     StructuredCloneData so we can serialize/deserialize across IPC.
  36 //     The move constructor problems in StructuredCloneData (bug 1462676),
  37 //     though, makes it hard to pass it around.  Passing a ref-counted
  38 //     pointer addresses this problem.
  39 //  2. Normally StructuredCloneData runs into problems if you try to move
  40 //     it across thread boundaries because it releases its SharedJSAllocatedData
  41 //     on the wrong thread.  This helper will correctly proxy release the
  42 //     shared data on the correct thread.
  43 //
  44 // This helper class should really just be used to serialize on one thread
  45 // and then move the reference across thread/process boundries to the
  46 // target worker thread.  This class is not intended to support simultaneous
  47 // read/write operations from different threads at the same time.
  48 class ServiceWorkerCloneData final : public ipc::StructuredCloneData {
  49   nsCOMPtr<nsISerialEventTarget> mEventTarget;
  50   bool mIsErrorMessageData;
  51
  52   ~ServiceWorkerCloneData();
  53
  54  public:
  55   ServiceWorkerCloneData();
  56
  57   bool BuildClonedMessageData(ClonedOrErrorMessageData& aClonedData);
  58
  59   void CopyFromClonedMessageData(const ClonedOrErrorMessageData& aClonedData);
  60
  61   void SetAsErrorMessageData();
  62
  63   bool IsErrorMessageData() const;
  64
  65   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ServiceWorkerCloneData)
  66 };
  67
  68 }  // namespace dom
  69 }  // namespace mozilla
  70
  71 #endif  // mozilla_dom_ServiceWorkerCloneData_h__