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