Fix: lttng: poptGetArg doesn't provide string ownership
[lttng-tools.git] / src / common / urcu.hpp
1 /*
2 * Copyright (C) 2022 Jérémie Galarneau <jeremie.galarneau@efficios.com>
3 *
4 * SPDX-License-Identifier: LGPL-2.1-only
5 *
6 */
7
8 #ifndef LTTNG_URCU_H
9 #define LTTNG_URCU_H
10
11 #define _LGPL_SOURCE
12 #include <urcu.h>
13 #include <mutex>
14
15 namespace lttng {
16 namespace urcu {
17
18 namespace details {
19 /*
20 * Wrapper around an urcu read lock which satisfies the 'Mutex' named
21 * requirements of C++11. Satisfying those requirements facilitates the use of
22 * standard concurrency support library facilities.
23 *
24 * read_lock is under the details namespace since it is unlikely to be used
25 * directly by exception-safe code. See read_lock_guard.
26 */
27 class read_lock {
28 public:
29 read_lock() = default;
30
31 /* "Not copyable" and "not moveable" Mutex requirements. */
32 read_lock(read_lock const &) = delete;
33 read_lock &operator=(read_lock const &) = delete;
34
35 void lock()
36 {
37 rcu_read_lock();
38 }
39
40 bool try_lock()
41 {
42 lock();
43 return true;
44 }
45
46 void unlock()
47 {
48 rcu_read_unlock();
49 }
50 };
51 } /* namespace details */
52
53 /*
54 * Provides the basic concept of std::lock_guard for rcu reader locks.
55 *
56 * The RCU reader lock is held for the duration of lock_guard's lifetime.
57 */
58 class read_lock_guard {
59 public:
60 read_lock_guard() : _guard(_lock)
61 {
62 }
63
64 read_lock_guard(const read_lock_guard &) = delete;
65
66 private:
67 details::read_lock _lock;
68 std::lock_guard<details::read_lock> _guard;
69 };
70
71 using unique_read_lock = std::unique_lock<details::read_lock>;
72
73 } /* namespace urcu */
74 } /* namespace lttng */
75
76 #endif /* LTTNG_URCU_H */
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