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
|
/*
* Copyright (C) 2006, 2007, 2009 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#ifndef TreeShared_h
#define TreeShared_h
#include <wtf/Assertions.h>
#include <wtf/Noncopyable.h>
namespace WebCore {
template<class T> class TreeShared : public Noncopyable {
public:
TreeShared(int initialRefCount = 1)
: m_refCount(initialRefCount)
, m_parent(0)
{
#ifndef NDEBUG
m_deletionHasBegun = false;
m_inRemovedLastRefFunction = false;
#endif
}
virtual ~TreeShared()
{
ASSERT(m_deletionHasBegun);
}
void ref()
{
ASSERT(!m_deletionHasBegun);
ASSERT(!m_inRemovedLastRefFunction);
++m_refCount;
}
void deref()
{
ASSERT(!m_deletionHasBegun);
ASSERT(!m_inRemovedLastRefFunction);
if (--m_refCount <= 0 && !m_parent) {
#ifndef NDEBUG
m_inRemovedLastRefFunction = true;
#endif
removedLastRef();
}
}
bool hasOneRef() const
{
ASSERT(!m_deletionHasBegun);
ASSERT(!m_inRemovedLastRefFunction);
return m_refCount == 1;
}
int refCount() const
{
return m_refCount;
}
void setParent(T* parent) { m_parent = parent; }
T* parent() const { return m_parent; }
#ifndef NDEBUG
bool m_deletionHasBegun;
bool m_inRemovedLastRefFunction;
#endif
private:
virtual void removedLastRef()
{
#ifndef NDEBUG
m_deletionHasBegun = true;
#endif
delete this;
}
int m_refCount;
T* m_parent;
};
}
#endif // TreeShared.h
|
