blob: 518eac78d58abd5bdde6c62f82e68b4697bbd666 (
plain)
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
181
182
183
184
185
186
|
// **********************************************************************
//
// Copyright (c) 2001
// IONA Technologies, Inc.
// Waltham, MA, USA
//
// All Rights Reserved
//
// **********************************************************************
#ifndef ICE_UTIL_RW_REC_MUTEX_H
#define ICE_UTIL_RW_REC_MUTEX_H
#include <IceUtil/Mutex.h>
#include <IceUtil/Cond.h>
namespace IceUtil
{
template <typename T>
class RLock
{
public:
RLock(const T& mutex) :
_mutex(mutex)
{
_mutex.readLock();
}
~RLock()
{
_mutex.unlock();
}
private:
const T& _mutex;
};
template <typename T>
class TryRLock
{
public:
TryRLock(const T& mutex) :
_mutex(mutex)
{
_mutex.tryReadLock();
}
~TryRLock()
{
_mutex.unlock();
}
private:
const T& _mutex;
};
template <typename T>
class WLock
{
public:
WLock(const T& mutex) :
_mutex(mutex)
{
_mutex.writeLock();
}
~WLock()
{
_mutex.unlock();
}
private:
const T& _mutex;
};
template <typename T>
class TryWLock
{
public:
TryWLock(const T& mutex) :
_mutex(mutex)
{
_mutex.tryWriteLock();
}
~TryWLock()
{
_mutex.unlock();
}
private:
const T& _mutex;
};
//
// Concurrency primitive that allows many readers & one writer access
// to a data structure. Writers have priority over readers. The
// structure is not strictly fair in that there is no absolute queue
// of waiting writers - that is managed by a condition variable.
//
class ICE_UTIL_API RWRecMutex
{
public:
//
// RLock (reader) & WLock (writer) typedefs.
//
typedef RLock<RWRecMutex> RLock;
typedef TryRLock<RWRecMutex> TryRLock;
typedef WLock<RWRecMutex> WLock;
typedef TryWLock<RWRecMutex> TryWLock;
RWRecMutex();
~RWRecMutex();
//
// Note that readLock/writeLock & unlock in general should not be
// used directly. Instead use RLock & WLock.
//
//
// Acquire a read lock.
//
void readLock() const;
//
// Try to acquire a read lock.
//
void tryReadLock() const;
//
// Acquire a write lock.
//
void writeLock() const;
//
// Acquire a write lock.
//
void tryWriteLock() const;
//
// Unlock the reader/writer lock.
//
void unlock() const;
private:
// noncopyable
RWRecMutex(const RWRecMutex&);
void operator=(const RWRecMutex&);
//
// Number of readers holding the lock. -1 means a writer has the
// lock.
//
mutable int _count;
//
// Number of waiting writers.
//
mutable unsigned int _waitingWriters;
//
// Internal mutex.
//
Mutex _mutex;
//
// Two condition variables for waiting readers & writers.
//
mutable Cond _readers;
mutable Cond _writers;
};
} // End namespace IceUtil
#endif
|
