jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#pragma once
28
29#include <AK/Assertions.h>
30#include <AK/Atomic.h>
31#include <AK/Types.h>
32#include <Kernel/Arch/i386/CPU.h>
33#include <Kernel/Forward.h>
34#include <Kernel/WaitQueue.h>
35
36namespace Kernel {
37
38class Lock {
39public:
40 Lock(const char* name = nullptr)
41 : m_name(name)
42 {
43 }
44 ~Lock() {}
45
46 void lock();
47 void unlock();
48 bool force_unlock_if_locked();
49 bool is_locked() const { return m_holder; }
50
51 const char* name() const { return m_name; }
52
53private:
54 Atomic<bool> m_lock { false };
55 u32 m_level { 0 };
56 Thread* m_holder { nullptr };
57 const char* m_name { nullptr };
58 WaitQueue m_queue;
59};
60
61class Locker {
62public:
63 [[gnu::always_inline]] inline explicit Locker(Lock& l)
64 : m_lock(l)
65 {
66 lock();
67 }
68 [[gnu::always_inline]] inline ~Locker() { unlock(); }
69 [[gnu::always_inline]] inline void unlock() { m_lock.unlock(); }
70 [[gnu::always_inline]] inline void lock() { m_lock.lock(); }
71
72private:
73 Lock& m_lock;
74};
75
76#define LOCKER(lock) Locker locker(lock)
77
78template<typename T>
79class Lockable {
80public:
81 Lockable() {}
82 Lockable(T&& resource)
83 : m_resource(move(resource))
84 {
85 }
86 Lock& lock() { return m_lock; }
87 T& resource() { return m_resource; }
88
89 T lock_and_copy()
90 {
91 LOCKER(m_lock);
92 return m_resource;
93 }
94
95private:
96 T m_resource;
97 Lock m_lock;
98};
99
100}