blob: 07a2b3ed198d7ebab0b1e27d1a0ec5006a3116c8 (
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
|
/******************************************************************************
*
* $Id: $
*
* Copyright (C) 1997-2012 by Dimitri van Heesch.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation under the terms of the GNU General Public License is hereby
* granted. No representations are made about the suitability of this software
* for any purpose. It is provided "as is" without express or implied warranty.
* See the GNU General Public License for more details.
*
* Documents produced by Doxygen are derivative works derived from the
* input used in their production; they are not affected by this license.
*
*/
#ifndef LOCKINGPTR_H
#define LOCKINGPTR_H
/*! @brief Abstract interface for lockable objects.
*
* By implementing this interface, a smart pointer can be created which
* will lock this object. This is used to prevent that an internal pointer
* owned by a lockable object would become invalid when the object is removed from
* memory, leaving the client with an invalid pointer. By letting the client use
* a smart pointer instead of the real object the object will be locked into
* memory until the pointer is no longer used, at which point the owner object will be
* unlock and can be removed from memory.
*/
class LockableObj
{
public:
LockableObj() : m_lockCount(0) {}
virtual ~LockableObj() {}
/*! Returns TRUE if the object is currently locked. */
bool isLocked() const { return m_lockCount>0; }
//VC++6.0 workaround
// protected:
/*! Called when the object is locked. */
virtual void lock() const = 0;
/*! Called when the object is unlocked. */
virtual void unlock() const = 0;
//VC++6.0 workaround
// private:
// template<class T> friend class LockingPtr;
int m_lockCount;
};
/*! @brief Smart pointer which keeps a lock on the owner of the pointer.
*
* With the pointer an owner object derived from LockableObj is associated.
* As long as the smart object exists it will keep a lock on the obj by calling
* LockableObj::lock(). Smart pointers can be copied and passed by value. As
* soon as there or no more smart pointer references to the object,
* LockableObj::unlock() will be called automatically.
*/
template<class T> class LockingPtr
{
LockableObj *m_owner;
const T *m_ptr;
public:
/*! Creates a smart pointer for pointer \a p owned by object \a o.
*/
LockingPtr(const LockableObj *o,const T* p)
{
if (o->m_lockCount==0) o->lock();
m_owner = (LockableObj *)o;
m_owner->m_lockCount++;
m_ptr = p;
}
/*! Copies the smart pointer \a lp
*/
LockingPtr(const LockingPtr &lp)
{
m_ptr = lp.m_ptr;
m_owner = lp.m_owner;
m_owner->m_lockCount++;
}
/*! Assigns the smart pointer \a lp
*/
LockingPtr &operator=(const LockingPtr &lp)
{
m_owner->m_lockCount--;
if (m_owner->m_lockCount==0) // no more references
{
m_owner->unlock();
}
m_ptr = lp.m_ptr;
m_owner = lp.m_owner;
m_owner->m_lockCount++;
return *this;
}
/*! Destroys the smart pointer, will unlock the owner.
*/
~LockingPtr()
{
m_owner->m_lockCount--;
if (m_owner->m_lockCount==0) // no more references
{
m_owner->unlock();
}
}
bool isNull() const
{
return m_ptr==0;
}
bool operator!() const
{
return !m_ptr;
}
bool operator==(T *p) const
{
return m_ptr==p;
}
bool operator==(const LockingPtr &lp) const
{
return m_ptr==lp.m_ptr;
}
bool operator!=(T *p) const
{
return m_ptr!=p;
}
bool operator!=(const LockingPtr &lp) const
{
return m_ptr!=lp.m_ptr;
}
/*! Dereference operator */
const T& operator* () const
{
return *m_ptr;
}
T* pointer() const
{
return (T*)m_ptr;
}
/*! Pointer operator */
T* operator-> () const
{
return (T*)m_ptr;
}
};
#endif // LOCKINGPTR_H
|
