1// Copyright (c) 2010 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CHROME_COMMON_MULTI_PROCESS_LOCK_H_
6#define CHROME_COMMON_MULTI_PROCESS_LOCK_H_
7#pragma once
8
9#include <sys/types.h>
10#include <string>
11
12// Platform abstraction for a lock that can be shared between processes.
13// The process that owns the lock will release it on exit even if
14// the exit is due to a crash. Locks are not recursive.
15class MultiProcessLock {
16 public:
17
18  // The length of a multi-process lock name is limited on Linux, so
19  // it is limited it on all platforms for consistency. This length does
20  // not include a terminator.
21  static const size_t MULTI_PROCESS_LOCK_NAME_MAX_LEN = 106;
22
23  // Factory method for creating a multi-process lock.
24  // |name| is the name of the lock. The name has special meaning on Windows
25  // where the prefix can determine the namespace of the lock.
26  // See http://msdn.microsoft.com/en-us/library/aa382954(v=VS.85).aspx for
27  // details.
28  static MultiProcessLock* Create(const std::string& name);
29
30  virtual ~MultiProcessLock() { }
31
32  // Try to grab ownership of the lock.
33  virtual bool TryLock() = 0;
34
35  // Release ownership of the lock.
36  virtual void Unlock() = 0;
37};
38
39#endif  // CHROME_COMMON_MULTI_PROCESS_LOCK_H_
40