author Clint Talbert <ctalbert@mozilla.com>
Wed, 13 Jan 2010 14:44:49 -0800
changeset 37161 b5d9fbeec04ed773b9f8c23973fe0e16e301343b
parent 36152 5ffc5409203c649967a622154eb7437eeb10fdd8
child 40908 4116478e20022a97885b9eacbbb70e73e28827c6
permissions -rw-r--r--
Orange on Bd builds: Backed out changeset 745af1f3dbf5

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=8 et :
/* ***** 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 IPC.
 * The Initial Developer of the Original Code is
 *   The Mozilla Foundation
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
 * Contributor(s):
 * 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
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 * ***** END LICENSE BLOCK ***** */

#ifndef mozilla_ipc_SharedMemory_h
#define mozilla_ipc_SharedMemory_h

#include "base/shared_memory.h"

#include "nsDebug.h"

// This is a low-level wrapper around platform shared memory.  Don't
// use it directly; use Shmem allocated through IPDL interfaces.
namespace {
enum Rights {
  RightsNone = 0,
  RightsRead = 1 << 0,
  RightsWrite = 1 << 1

namespace mozilla {
namespace ipc {

class SharedMemory : public base::SharedMemory
  typedef base::SharedMemoryHandle SharedMemoryHandle;

  SharedMemory() :

  SharedMemory(const SharedMemoryHandle& aHandle) :
    base::SharedMemory(aHandle, false),

  bool Map(size_t nBytes)
    bool ok = base::SharedMemory::Map(nBytes);
    if (ok)
      mSize = nBytes;
    return ok;

  size_t Size()
    return mSize;

  Protect(char* aAddr, size_t aSize, int aRights)
    char* memStart = reinterpret_cast<char*>(memory());
    if (!memStart)
      NS_RUNTIMEABORT("SharedMemory region points at NULL!");
    char* memEnd = memStart + Size();

    char* protStart = aAddr;
    if (!protStart)
      NS_RUNTIMEABORT("trying to Protect() a NULL region!");
    char* protEnd = protStart + aSize;

    if (!(memStart <= protStart
          && protEnd <= memEnd))
      NS_RUNTIMEABORT("attempt to Protect() a region outside this SharedMemory");

    // checks alignment etc.
    SystemProtect(aAddr, aSize, aRights);

  static void SystemProtect(char* aAddr, size_t aSize, int aRights);
  static size_t SystemPageSize();

  // NB: we have to track this because shared_memory_win.cc doesn't
  size_t mSize;

} // namespace ipc
} // namespace mozilla

#endif // ifndef mozilla_ipc_SharedMemory_h