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1 | /* |
2 | * Copyright Andrey Semashev 2007 - 2015. | |
3 | * Distributed under the Boost Software License, Version 1.0. | |
4 | * (See accompanying file LICENSE_1_0.txt or copy at | |
5 | * http://www.boost.org/LICENSE_1_0.txt) | |
6 | */ | |
7 | /*! | |
8 | * \file locks.hpp | |
9 | * \author Andrey Semashev | |
10 | * \date 30.05.2010 | |
11 | * | |
12 | * \brief This header is the Boost.Log library implementation, see the library documentation | |
13 | * at http://www.boost.org/doc/libs/release/libs/log/doc/html/index.html. | |
14 | */ | |
15 | ||
16 | #ifndef BOOST_LOG_DETAIL_LOCKS_HPP_INCLUDED_ | |
17 | #define BOOST_LOG_DETAIL_LOCKS_HPP_INCLUDED_ | |
18 | ||
19 | #include <boost/log/detail/config.hpp> | |
20 | #include <boost/log/detail/header.hpp> | |
21 | ||
22 | #ifdef BOOST_HAS_PRAGMA_ONCE | |
23 | #pragma once | |
24 | #endif | |
25 | ||
26 | namespace boost { | |
27 | ||
28 | #ifndef BOOST_LOG_NO_THREADS | |
29 | ||
30 | // Forward declaration of Boost.Thread locks. Specified here to avoid including Boost.Thread, | |
31 | // which would bring in many dependent headers, including a great deal of Boost.DateTime. | |
32 | template< typename > | |
33 | class lock_guard; | |
34 | template< typename > | |
35 | class shared_lock_guard; | |
36 | template< typename > | |
37 | class shared_lock; | |
38 | template< typename > | |
39 | class upgrade_lock; | |
40 | template< typename > | |
41 | class unique_lock; | |
42 | ||
43 | template< typename > | |
44 | struct is_mutex_type; | |
45 | ||
46 | #endif // BOOST_LOG_NO_THREADS | |
47 | ||
48 | BOOST_LOG_OPEN_NAMESPACE | |
49 | ||
50 | //! An auxiliary pseudo-lock to express no locking requirements in logger features | |
51 | template< typename MutexT > | |
52 | class no_lock | |
53 | { | |
54 | public: | |
55 | /*! | |
56 | * Constructs the pseudo-lock. The mutex is not affected during the construction. | |
57 | */ | |
20effc67 | 58 | explicit no_lock(MutexT&) BOOST_NOEXCEPT {} |
7c673cae FG |
59 | |
60 | private: | |
61 | no_lock(no_lock const&); | |
62 | no_lock& operator= (no_lock const&); | |
63 | }; | |
64 | ||
65 | namespace aux { | |
66 | ||
67 | #ifndef BOOST_LOG_NO_THREADS | |
68 | ||
69 | //! A trait to detect if the mutex supports exclusive locking | |
70 | template< typename MutexT > | |
71 | struct is_exclusively_lockable | |
72 | { | |
73 | typedef char true_type; | |
74 | struct false_type { char t[2]; }; | |
75 | ||
76 | template< typename T > | |
77 | static true_type check_lockable(T*, void (T::*)() = &T::lock, void (T::*)() = &T::unlock); | |
78 | static false_type check_lockable(void*); | |
79 | ||
80 | enum value_t { value = sizeof(check_lockable((MutexT*)NULL)) == sizeof(true_type) }; | |
81 | }; | |
82 | ||
83 | //! A trait to detect if the mutex supports shared locking | |
84 | template< typename MutexT > | |
85 | struct is_shared_lockable | |
86 | { | |
87 | typedef char true_type; | |
88 | struct false_type { char t[2]; }; | |
89 | ||
90 | template< typename T > | |
91 | static true_type check_shared_lockable(T*, void (T::*)() = &T::lock_shared, void (T::*)() = &T::unlock_shared); | |
92 | static false_type check_shared_lockable(void*); | |
93 | ||
94 | enum value_t { value = sizeof(check_shared_lockable((MutexT*)NULL)) == sizeof(true_type) }; | |
95 | }; | |
96 | ||
97 | //! A scope guard that automatically unlocks the mutex on destruction | |
98 | template< typename MutexT > | |
99 | struct exclusive_auto_unlocker | |
100 | { | |
101 | explicit exclusive_auto_unlocker(MutexT& m) BOOST_NOEXCEPT : m_Mutex(m) | |
102 | { | |
103 | } | |
104 | ~exclusive_auto_unlocker() | |
105 | { | |
106 | m_Mutex.unlock(); | |
107 | } | |
108 | ||
109 | BOOST_DELETED_FUNCTION(exclusive_auto_unlocker(exclusive_auto_unlocker const&)) | |
110 | BOOST_DELETED_FUNCTION(exclusive_auto_unlocker& operator= (exclusive_auto_unlocker const&)) | |
111 | ||
112 | protected: | |
113 | MutexT& m_Mutex; | |
114 | }; | |
115 | ||
116 | //! An analogue to the minimalistic \c lock_guard template. Defined here to avoid including Boost.Thread. | |
117 | template< typename MutexT > | |
118 | struct exclusive_lock_guard | |
119 | { | |
20effc67 | 120 | explicit exclusive_lock_guard(MutexT& m) BOOST_NOEXCEPT_IF(BOOST_NOEXCEPT_EXPR(m.lock())) : m_Mutex(m) |
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121 | { |
122 | m.lock(); | |
123 | } | |
124 | ~exclusive_lock_guard() | |
125 | { | |
126 | m_Mutex.unlock(); | |
127 | } | |
128 | ||
129 | BOOST_DELETED_FUNCTION(exclusive_lock_guard(exclusive_lock_guard const&)) | |
130 | BOOST_DELETED_FUNCTION(exclusive_lock_guard& operator= (exclusive_lock_guard const&)) | |
131 | ||
132 | private: | |
133 | MutexT& m_Mutex; | |
134 | }; | |
135 | ||
136 | //! An analogue to the minimalistic \c lock_guard template that locks \c shared_mutex with shared ownership. | |
137 | template< typename MutexT > | |
138 | struct shared_lock_guard | |
139 | { | |
20effc67 | 140 | explicit shared_lock_guard(MutexT& m) BOOST_NOEXCEPT_IF(BOOST_NOEXCEPT_EXPR(m.lock_shared())) : m_Mutex(m) |
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141 | { |
142 | m.lock_shared(); | |
143 | } | |
144 | ~shared_lock_guard() | |
145 | { | |
146 | m_Mutex.unlock_shared(); | |
147 | } | |
148 | ||
149 | BOOST_DELETED_FUNCTION(shared_lock_guard(shared_lock_guard const&)) | |
150 | BOOST_DELETED_FUNCTION(shared_lock_guard& operator= (shared_lock_guard const&)) | |
151 | ||
152 | private: | |
153 | MutexT& m_Mutex; | |
154 | }; | |
155 | ||
156 | //! A deadlock-safe lock type that exclusively locks two mutexes | |
157 | template< typename MutexT1, typename MutexT2 > | |
158 | class multiple_unique_lock2 | |
159 | { | |
160 | public: | |
20effc67 | 161 | multiple_unique_lock2(MutexT1& m1, MutexT2& m2) BOOST_NOEXCEPT_IF(BOOST_NOEXCEPT_EXPR(m1.lock()) && BOOST_NOEXCEPT_EXPR(m2.lock())) : |
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162 | m_p1(&m1), |
163 | m_p2(&m2) | |
164 | { | |
165 | // Yes, it's not conforming, but it works | |
166 | // and it doesn't require to #include <functional> | |
167 | if (static_cast< void* >(m_p1) < static_cast< void* >(m_p2)) | |
168 | { | |
169 | m_p1->lock(); | |
170 | m_p2->lock(); | |
171 | } | |
172 | else | |
173 | { | |
174 | m_p2->lock(); | |
175 | m_p1->lock(); | |
176 | } | |
177 | } | |
178 | ~multiple_unique_lock2() | |
179 | { | |
180 | m_p2->unlock(); | |
181 | m_p1->unlock(); | |
182 | } | |
183 | ||
184 | private: | |
185 | MutexT1* m_p1; | |
186 | MutexT2* m_p2; | |
187 | }; | |
188 | ||
189 | #endif // BOOST_LOG_NO_THREADS | |
190 | ||
191 | } // namespace aux | |
192 | ||
193 | BOOST_LOG_CLOSE_NAMESPACE // namespace log | |
194 | ||
195 | } // namespace boost | |
196 | ||
197 | #include <boost/log/detail/footer.hpp> | |
198 | ||
199 | #endif // BOOST_LOG_DETAIL_LOCKS_HPP_INCLUDED_ |