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
|
/** @file
* IPRT - RTLock Classes for Scope-based Locking.
*/
/*
* Copyright (C) 2007 Sun Microsystems, Inc.
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE 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.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 USA or visit http://www.sun.com if you need
* additional information or have any questions.
*/
#ifndef ___iprt_lock_h
#define ___iprt_lock_h
#include <iprt/critsect.h>
__BEGIN_DECLS
/** @defgroup grp_rt_lock RTLock - Scope-based Locking (C++).
* @ingroup grp_rt
* @{
*/
class RTLock;
/**
* The mutex lock.
*
* This is used as a 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 RTLock.
*/
class RTLockMtx
{
friend class RTLock;
private:
RTCRITSECT mMtx;
public:
RTLockMtx()
{
RTCritSectInit(&mMtx);
}
~RTLockMtx()
{
RTCritSectDelete(&mMtx);
}
// lock() and unlock() are private so that only
// friend RTLock 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 RTLockMtx and to not forget releasing it.
* To request a RTLockMtx, simply create an instance of RTLock
* on the stack and pass the mutex to it:
*
* @code
extern RTLockMtx gMtx; // wherever this is
...
if (...)
{
RTLock lock(gMtx);
... // do stuff
// when lock goes out of scope, destructor releases the mutex
}
@endcode
*
* You can also explicitly release the mutex by calling RTLock::release().
* This might be helpful if the lock doesn't go out of scope early enough
* for your mutex to be released.
*/
class RTLock
{
private:
RTLockMtx &mMtx;
bool mfLocked;
public:
RTLock(RTLockMtx &aMtx)
: mMtx(aMtx)
{
mMtx.lock();
mfLocked = true;
}
~RTLock()
{
if (mfLocked)
mMtx.unlock();
}
inline void release()
{
if (mfLocked)
{
mMtx.unlock();
mfLocked = false;
}
}
};
/** @} */
__END_DECLS
#endif
|
