gecko-dev/ipc/glue/SharedMemoryBasic_android.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at:
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Code.
 *
 * The Initial Developer of the Original Code is
 *   The Mozilla Foundation
 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Chris Jones <jones.chris.g@gmail.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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 * the provisions above, a recipient may use your version of this file under
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 *
 * ***** END LICENSE BLOCK ***** */

#ifndef mozilla_ipc_SharedMemoryBasic_android_h
#define mozilla_ipc_SharedMemoryBasic_android_h

#include "base/file_descriptor_posix.h"

#include "SharedMemory.h"

//
// This is a low-level wrapper around platform shared memory.  Don't
// use it directly; use Shmem allocated through IPDL interfaces.
//

namespace mozilla {
namespace ipc {

class SharedMemoryBasic : public SharedMemory
{
public:
  typedef base::FileDescriptor Handle;

  SharedMemoryBasic();

  SharedMemoryBasic(const Handle& aHandle);

  virtual ~SharedMemoryBasic();

  NS_OVERRIDE
  virtual bool Create(size_t aNbytes);

  NS_OVERRIDE
  virtual bool Map(size_t nBytes);

  NS_OVERRIDE
  virtual void* memory() const
  {
    return mMemory;
  }

  NS_OVERRIDE
  virtual SharedMemoryType Type() const
  {
    return TYPE_BASIC;
  }

  static Handle NULLHandle()
  {
    return Handle();
  }

  static bool IsHandleValid(const Handle &aHandle)
  {
    return aHandle.fd >= 0;
  }

  bool ShareToProcess(base::ProcessHandle aProcess,
                      Handle* aNewHandle);

private:
  void Unmap();
  void Destroy();

  // The /dev/ashmem fd we allocate.
  int mShmFd;
  // Pointer to mapped region, null if unmapped.
  void *mMemory;
};

} // namespace ipc
} // namespace mozilla

#endif // ifndef mozilla_ipc_SharedMemoryBasic_android_h