pjs/ipc/glue/CrossProcessMutex.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* ***** 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 Corporation code.
*
* The Initial Developer of the Original Code is Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2011
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Bas Schouten <bschouten@mozilla.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
* 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_CrossProcessMutex_h
#define mozilla_CrossProcessMutex_h
#include "base/process.h"
#include "mozilla/Mutex.h"
namespace IPC {
template<typename T>
struct ParamTraits;
}
//
// Provides:
//
// - CrossProcessMutex, a non-recursive mutex that can be shared across processes
// - CrossProcessMutexAutoLock, an RAII class for ensuring that Mutexes are
// properly locked and unlocked
//
// Using CrossProcessMutexAutoLock/CrossProcessMutexAutoUnlock is MUCH
// preferred to making bare calls to CrossProcessMutex.Lock and Unlock.
//
namespace mozilla {
#ifdef XP_WIN
typedef HANDLE CrossProcessMutexHandle;
#else
// Stub for other platforms. We can't use uintptr_t here since different
// processes could disagree on its size.
typedef uintptr_t CrossProcessMutexHandle;
#endif
class NS_COM_GLUE CrossProcessMutex
{
public:
/**
* CrossProcessMutex
* @param name A name which can reference this lock (currently unused)
**/
CrossProcessMutex(const char* aName);
/**
* CrossProcessMutex
* @param handle A handle of an existing cross process mutex that can be
* opened.
*/
CrossProcessMutex(CrossProcessMutexHandle aHandle);
/**
* ~CrossProcessMutex
**/
~CrossProcessMutex();
/**
* Lock
* This will lock the mutex. Any other thread in any other process that
* has access to this mutex calling lock will block execution until the
* initial caller of lock has made a call to Unlock.
*
* If the owning process is terminated unexpectedly the mutex will be
* released.
**/
void Lock();
/**
* Unlock
* This will unlock the mutex. A single thread currently waiting on a lock
* call will resume execution and aquire ownership of the lock. No
* guarantees are made as to the order in which waiting threads will resume
* execution.
**/
void Unlock();
/**
* ShareToProcess
* This function is called to generate a serializable structure that can
* be sent to the specified process and opened on the other side.
*
* @returns A handle that can be shared to another process
*/
CrossProcessMutexHandle ShareToProcess(base::ProcessHandle aTarget);
private:
friend struct IPC::ParamTraits<CrossProcessMutex>;
CrossProcessMutex();
CrossProcessMutex(const CrossProcessMutex&);
CrossProcessMutex &operator=(const CrossProcessMutex&);
#ifdef XP_WIN
HANDLE mMutex;
#endif
};
typedef BaseAutoLock<CrossProcessMutex> CrossProcessMutexAutoLock;
typedef BaseAutoUnlock<CrossProcessMutex> CrossProcessMutexAutoUnlock;
}
#endif