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1 | // |
2 | // detail/scoped_lock.hpp | |
3 | // ~~~~~~~~~~~~~~~~~~~~~~ | |
4 | // | |
11fdf7f2 | 5 | // Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
7c673cae FG |
6 | // |
7 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
8 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
9 | // | |
10 | ||
11 | #ifndef BOOST_ASIO_DETAIL_SCOPED_LOCK_HPP | |
12 | #define BOOST_ASIO_DETAIL_SCOPED_LOCK_HPP | |
13 | ||
14 | #if defined(_MSC_VER) && (_MSC_VER >= 1200) | |
15 | # pragma once | |
16 | #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) | |
17 | ||
18 | #include <boost/asio/detail/noncopyable.hpp> | |
19 | ||
20 | #include <boost/asio/detail/push_options.hpp> | |
21 | ||
22 | namespace boost { | |
23 | namespace asio { | |
24 | namespace detail { | |
25 | ||
26 | // Helper class to lock and unlock a mutex automatically. | |
27 | template <typename Mutex> | |
28 | class scoped_lock | |
29 | : private noncopyable | |
30 | { | |
31 | public: | |
32 | // Tag type used to distinguish constructors. | |
33 | enum adopt_lock_t { adopt_lock }; | |
34 | ||
35 | // Constructor adopts a lock that is already held. | |
36 | scoped_lock(Mutex& m, adopt_lock_t) | |
37 | : mutex_(m), | |
38 | locked_(true) | |
39 | { | |
40 | } | |
41 | ||
42 | // Constructor acquires the lock. | |
43 | explicit scoped_lock(Mutex& m) | |
44 | : mutex_(m) | |
45 | { | |
46 | mutex_.lock(); | |
47 | locked_ = true; | |
48 | } | |
49 | ||
50 | // Destructor releases the lock. | |
51 | ~scoped_lock() | |
52 | { | |
53 | if (locked_) | |
54 | mutex_.unlock(); | |
55 | } | |
56 | ||
57 | // Explicitly acquire the lock. | |
58 | void lock() | |
59 | { | |
60 | if (!locked_) | |
61 | { | |
62 | mutex_.lock(); | |
63 | locked_ = true; | |
64 | } | |
65 | } | |
66 | ||
67 | // Explicitly release the lock. | |
68 | void unlock() | |
69 | { | |
70 | if (locked_) | |
71 | { | |
72 | mutex_.unlock(); | |
73 | locked_ = false; | |
74 | } | |
75 | } | |
76 | ||
77 | // Test whether the lock is held. | |
78 | bool locked() const | |
79 | { | |
80 | return locked_; | |
81 | } | |
82 | ||
83 | // Get the underlying mutex. | |
84 | Mutex& mutex() | |
85 | { | |
86 | return mutex_; | |
87 | } | |
88 | ||
89 | private: | |
90 | // The underlying mutex. | |
91 | Mutex& mutex_; | |
92 | ||
93 | // Whether the mutex is currently locked or unlocked. | |
94 | bool locked_; | |
95 | }; | |
96 | ||
97 | } // namespace detail | |
98 | } // namespace asio | |
99 | } // namespace boost | |
100 | ||
101 | #include <boost/asio/detail/pop_options.hpp> | |
102 | ||
103 | #endif // BOOST_ASIO_DETAIL_SCOPED_LOCK_HPP |