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
|
/** @file
* IPRT - Classes for Scope-based Locking.
*/
/*
* Copyright (C) 2007-2025 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
#ifndef IPRT_INCLUDED_cpp_lock_h
#define IPRT_INCLUDED_cpp_lock_h
#ifndef RT_WITHOUT_PRAGMA_ONCE
# pragma once
#endif
#include <iprt/critsect.h>
#ifdef RT_LOCK_STRICT
# include <iprt/lockvalidator.h>
#endif
RT_C_DECLS_BEGIN
/** @defgroup grp_rt_cpp_lock C++ Scope-based Locking
* @ingroup grp_rt_cpp
* @{
*/
class RTCLock;
/**
* The mutex lock.
*
* This is used as an object data member if the intention is to lock
* a single object. This can also be used statically, initialized in
* a global variable, for class wide purposes.
*
* This is best used together with RTCLock.
*/
class RTCLockMtx
{
friend class RTCLock;
private:
RTCRITSECT mMtx;
public:
RTCLockMtx()
{
#ifdef RT_LOCK_STRICT_ORDER
RTCritSectInitEx(&mMtx, 0 /*fFlags*/,
RTLockValidatorClassCreateUnique(RT_SRC_POS, NULL),
RTLOCKVAL_SUB_CLASS_NONE, NULL);
#else
RTCritSectInit(&mMtx);
#endif
}
/** Use to when creating locks that belongs in the same "class". */
RTCLockMtx(RT_SRC_POS_DECL, uint32_t uSubClass = RTLOCKVAL_SUB_CLASS_NONE)
{
#ifdef RT_LOCK_STRICT_ORDER
RTCritSectInitEx(&mMtx, 0 /*fFlags*/,
RTLockValidatorClassForSrcPos(RT_SRC_POS_ARGS, NULL),
uSubClass, NULL);
#else
NOREF(uSubClass);
RTCritSectInit(&mMtx);
RT_SRC_POS_NOREF();
#endif
}
~RTCLockMtx()
{
RTCritSectDelete(&mMtx);
}
/* lock() and unlock() are private so that only friend RTCLock can access
them. */
private:
inline void lock()
{
RTCritSectEnter(&mMtx);
}
inline void unlock()
{
RTCritSectLeave(&mMtx);
}
};
/**
* The stack object for automatic locking and unlocking.
*
* This is a helper class for automatic locks, to simplify requesting a
* RTCLockMtx and to not forget releasing it. To request a RTCLockMtx, simply
* create an instance of RTCLock on the stack and pass the mutex to it:
*
* @code
extern RTCLockMtx gMtx; // wherever this is
...
if (...)
{
RTCLock lock(gMtx);
... // do stuff
// when lock goes out of scope, destructor releases the mutex
}
@endcode
*
* You can also explicitly release the mutex by calling RTCLock::release().
* This might be helpful if the lock doesn't go out of scope early enough
* for your mutex to be released.
*/
class RTCLock
{
private:
/** Reference to the lock we're holding. */
RTCLockMtx &m_rMtx;
/** Whether we're currently holding the lock of if it was already
* explictily released by the release() method. */
bool m_fLocked;
public:
RTCLock(RTCLockMtx &a_rMtx)
: m_rMtx(a_rMtx)
{
m_rMtx.lock();
m_fLocked = true;
}
~RTCLock()
{
if (m_fLocked)
m_rMtx.unlock();
}
inline void release()
{
if (m_fLocked)
{
m_rMtx.unlock();
m_fLocked = false;
}
}
};
/** @} */
RT_C_DECLS_END
#endif /* !IPRT_INCLUDED_cpp_lock_h */
|
