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
|
/***************************************************************************
* Copyright (C) 2006-2007 by Rajko Albrecht *
* ral@alwins-world.de *
* *
* 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; either version 2 of the License, or *
* (at your option) any later version. *
* *
* 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, write to the *
* Free Software Foundation, Inc., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
***************************************************************************/
#ifndef _smart_pointer_hpp
#define _smart_pointer_hpp
#if defined QT_THREAD_SUPPORT
#include "qmutex.h"
#endif
#include "svnqt/svnqt_defines.hpp"
/*!
* \file smart_pointer.h
* \brief smart pointer and reference counter
* \author Rajko Albrecht
*
*/
namespace svn
{
//! simple reference counter class
class ref_count {
protected:
//! reference count member
long m_RefCount;
#ifdef QT_THREAD_SUPPORT
QMutex m_RefcountMutex;
#endif
public:
//! first reference must be added after "new" via Pointer()
ref_count() : m_RefCount(0)
#ifdef QT_THREAD_SUPPORT
,m_RefcountMutex()
#endif
{}
virtual ~ref_count() {}
//! add a reference
void Incr() {
#ifdef QT_THREAD_SUPPORT
QMutexLocker a(&m_RefcountMutex);
#endif
++m_RefCount;
}
//! delete a reference
bool Decr() {
#ifdef QT_THREAD_SUPPORT
QMutexLocker a(&m_RefcountMutex);
#endif
--m_RefCount;
return Shared();
}
//! is it referenced
bool Shared() { return (m_RefCount > 0); }
};
//! reference counting wrapper class
template<class T> class smart_pointer {
//! pointer to object
/*!
* this object must contain Incr(), Decr() and Shared()
* methode as public members. The best way is, that it will be a child
* class of RefCount
*/
T *ptr;
public:
//! standart constructor
smart_pointer() { ptr = 0; }
//! standart destructor
/*!
* release the reference, if it were the last reference, destroys
* ptr
*/
~smart_pointer()
{
if (ptr && !ptr->Decr()) {
delete ptr;
}
}
//! construction
smart_pointer(T* t) { if ( (ptr = t) ) ptr->Incr(); }
//! Pointer copy
smart_pointer(const smart_pointer<T>& p)
{ if ( (ptr = p.ptr) ) ptr->Incr(); }
//! pointer copy by assignment
smart_pointer<T>& operator= (const smart_pointer<T>& p)
{
// already same: nothing to do
if (ptr == p.ptr) return *this;
// decouple reference
if ( ptr && !ptr->Decr()) delete ptr;
// establish new reference
if ( (ptr = p.ptr) ) ptr->Incr();
return *this;
}
smart_pointer<T>& operator= (T*p)
{
if (ptr==p)return *this;
if (ptr && !ptr->Decr()) delete ptr;
if ( (ptr=p) ) ptr->Incr();
return *this;
}
//! cast to conventional pointer
operator T* () const { return ptr; }
//! deref: fails for 0 pointer
T& operator* () {return *ptr; }
//! deref: fails for 0 pointer
const T& operator* ()const {return *ptr; }
//! deref with method call
T* operator-> () {return ptr; }
//! deref with const method call
const T* operator-> ()const {return ptr; }
//! supports "if (pointer)"
operator bool () const { return (ptr != 0); }
//! "if (pointer)" as non const
operator bool () { return ptr != 0;}
//! support if (!pointer)"
bool operator! () const { return (ptr == 0); }
//! support if (!pointer)" as non const
bool operator! () { return (ptr == 0); }
};
} // namespace svn
#endif
|
