1 | // |
2 | // detail/scoped_lock.hpp |
3 | // ~~~~~~~~~~~~~~~~~~~~~~ |
4 | // |
5 | // Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
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 |
104 | |