1//
2// detail/scoped_lock.hpp
3// ~~~~~~~~~~~~~~~~~~~~~~
4//
5// Copyright (c) 2003-2024 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
22namespace boost {
23namespace asio {
24namespace detail {
25
26// Helper class to lock and unlock a mutex automatically.
27template <typename Mutex>
28class scoped_lock
29 : private noncopyable
30{
31public:
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
89private:
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

source code of boost/libs/asio/include/boost/asio/detail/scoped_lock.hpp