File: auto_mutex_extension.h

package info (click to toggle)
concurrentqueue 1.0.3%2Bds-1
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 2,648 kB
  • sloc: cpp: 37,303; makefile: 88; ansic: 67; python: 46; sh: 18
file content (180 lines) | stat: -rw-r--r-- 4,212 bytes parent folder | download | duplicates (9)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
// Copyright (C) 2005  Davis E. King (davis@dlib.net)
// License: Boost Software License   See LICENSE.txt for the full license.
#ifndef DLIB_AUTO_MUTEX_EXTENSIOn_
#define DLIB_AUTO_MUTEX_EXTENSIOn_

#include "threads_kernel.h"
#include "rmutex_extension.h"
#include "read_write_mutex_extension.h"
#include "auto_mutex_extension_abstract.h"

namespace dlib
{

// ----------------------------------------------------------------------------------------

    class auto_mutex
    {
        /*!
            INITIAL VALUE
                - if (m != 0) then
                    - the mutex pointed to by m is locked
                - if (r != 0) then
                    - the mutex pointed to by r is locked
                - if (rw != 0) then
                    - the mutex pointed to by rw is locked
                - exactly one of r, m, or rw is not 0.

            CONVENTION
                - if (m != 0) then
                    - the mutex pointed to by m is locked
                - if (r != 0) then
                    - the mutex pointed to by r is locked
                - if (rw != 0) then
                    - the mutex pointed to by rw is locked
                - exactly one of r, m, or rw is not 0.
        !*/
    public:

        explicit auto_mutex (
            const mutex& m_
        ) : m(&m_),
            r(0),
            rw(0)
        {
            m->lock();
        }

        explicit auto_mutex (
            const rmutex& r_
        ) : m(0),
            r(&r_),
            rw(0)
        {
            r->lock();
        }

        explicit auto_mutex (
            const read_write_mutex& rw_
        ) : m(0),
            r(0),
            rw(&rw_)
        {
            rw->lock();
        }

        void unlock()
        {
            if (m != 0)
            {
                m->unlock();
                m = 0;
            }
            else if (r != 0)
            {
                r->unlock();
                r = 0;
            }
            else if (rw != 0)
            {
                rw->unlock();
                rw = 0;
            }
        }

        ~auto_mutex (
        )
        {
            unlock();
        }

    private:

        const mutex* m;
        const rmutex* r;
        const read_write_mutex* rw;

        // restricted functions
        auto_mutex(auto_mutex&);        // copy constructor
        auto_mutex& operator=(auto_mutex&);    // assignment operator
    };

// ----------------------------------------------------------------------------------------

    class auto_mutex_readonly
    {
    public:

        explicit auto_mutex_readonly (
            const read_write_mutex& rw_
        ) : rw(rw_), _has_write_lock(false), _has_read_lock(true)
        {
            rw.lock_readonly();
        }

        ~auto_mutex_readonly (
        )
        {
            unlock();
        }

        void lock_readonly (
        )
        {
            if (!_has_read_lock)
            {
                unlock();
                rw.lock_readonly();
                _has_read_lock = true;
            }
        }

        void lock_write (
        )
        {
            if (!_has_write_lock)
            {
                unlock();
                rw.lock();
                _has_write_lock = true;
            }
        }

        void unlock (
        )
        {
            if (_has_write_lock)
            {
                rw.unlock();
                _has_write_lock = false;
            }
            else if (_has_read_lock)
            {
                rw.unlock_readonly();
                _has_read_lock = false;
            }
        }

        bool has_read_lock (
        ) { return _has_read_lock; }

        bool has_write_lock (
        ) { return _has_write_lock; }

    private:

        const read_write_mutex& rw;
        bool _has_write_lock;
        bool _has_read_lock;

        // restricted functions
        auto_mutex_readonly(auto_mutex_readonly&);        // copy constructor
        auto_mutex_readonly& operator=(auto_mutex_readonly&);    // assignment operator
    };

// ----------------------------------------------------------------------------------------

}

#endif // DLIB_AUTO_MUTEX_EXTENSIOn_