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lockguard.h
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1 // The DAGFrameScheduler is a Multi-Threaded lock free and wait free scheduling library.
2 // © Copyright 2010 - 2014 BlackTopp Studios Inc.
3 /* This file is part of The DAGFrameScheduler.
4 
5  The DAGFrameScheduler is free software: you can redistribute it and/or modify
6  it under the terms of the GNU General Public License as published by
7  the Free Software Foundation, either version 3 of the License, or
8  (at your option) any later version.
9 
10  The DAGFrameScheduler is distributed in the hope that it will be useful,
11  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  GNU General Public License for more details.
14 
15  You should have received a copy of the GNU General Public License
16  along with The DAGFrameScheduler. If not, see <http://www.gnu.org/licenses/>.
17 */
18 /* The original authors have included a copy of the license specified above in the
19  'doc' folder. See 'gpl.txt'
20 */
21 /* We welcome the use of the DAGFrameScheduler to anyone, including companies who wish to
22  Build professional software and charge for their product.
23 
24  However there are some practical restrictions, so if your project involves
25  any of the following you should contact us and we will try to work something
26  out:
27  - DRM or Copy Protection of any kind(except Copyrights)
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30  - Are Currently In Violation of Another Copyright Holder's GPL License
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32  your distribution
33 
34  These and other limitations could cause serious legal problems if you ignore
35  them, so it is best to simply contact us or the Free Software Foundation, if
36  you have any questions.
37 
38  Joseph Toppi - toppij@gmail.com
39  John Blackwood - makoenergy02@gmail.com
40 */
41 #ifndef _lockguard_h
42 #define _lockguard_h
43 
44 // Parts of this library use the TinyThread++ libary and those parts are also covered by the following license
45 /*
46 Copyright (c) 2010-2012 Marcus Geelnard
47 
48 This software is provided 'as-is', without any express or implied
49 warranty. In no event will the authors be held liable for any damages
50 arising from the use of this software.
51 
52 Permission is granted to anyone to use this software for any purpose,
53 including commercial applications, and to alter it and redistribute it
54 freely, subject to the following restrictions:
55 
56  1. The origin of this software must not be misrepresented; you must not
57  claim that you wrote the original software. If you use this software
58  in a product, an acknowledgment in the product documentation would be
59  appreciated but is not required.
60 
61  2. Altered source versions must be plainly marked as such, and must not be
62  misrepresented as being the original software.
63 
64  3. This notice may not be removed or altered from any source
65  distribution.
66 */
67 
68 
69 /// @file
70 /// @brief Declares a tool for automatically unlocking a mutex in an exception safe way.
71 
72 namespace Mezzanine
73 {
74  namespace Threading
75  {
76  /// @brief Lock guard class.
77  /// @details The constructor locks the mutex, and the destructor unlocks the mutex, so
78  /// the mutex will automatically be unlocked when the lock guard goes out of
79  /// scope. Example usage:
80  /// @code
81  /// mutex m;
82  /// int counter;
83  ///
84  /// void increment()
85  /// {
86  /// lock_guard<mutex> guard(m);
87  /// ++counter;
88  /// }
89  /// @endcode
90  template <class T>
91  class lock_guard
92  {
93  public:
94  /// @brief This allows other code to use the type of this mutex in a more safe way.
95  typedef T mutex_type;
96 
97  /// @brief The constructor locks the mutex.
98  /// @param aMutex Any mutex which implements lock() and unlock().
99  explicit lock_guard(mutex_type& aMutex)
100  {
101  mMutex = &aMutex;
102  mMutex->lock();
103  }
104 
105  /// @brief The destructor unlocks the mutex.
107  {
108  if(mMutex)
109  mMutex->unlock();
110  }
111 
112  private:
113  /// @internal
114  /// @brief A non-owning pointer to the mutex.
115  mutex_type* mMutex;
116  };//lock_guard
117 
118 
119  }//Threading
120 }//Mezzanine
121 
122 #endif