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
|
/*
* Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 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 WTF_PassRefPtr_h
#define WTF_PassRefPtr_h
#include <wtf/GetPtr.h>
#include <wtf/Ref.h>
namespace WTF {
template<typename T> class RefPtr;
template<typename T> class PassRefPtr;
template<typename T> PassRefPtr<T> adoptRef(T*);
template<typename T> ALWAYS_INLINE void refIfNotNull(T* ptr)
{
if (LIKELY(ptr != nullptr))
ptr->ref();
}
template<typename T> ALWAYS_INLINE void derefIfNotNull(T* ptr)
{
if (LIKELY(ptr != nullptr))
ptr->deref();
}
template<typename T> class PassRefPtr {
public:
typedef T ValueType;
typedef ValueType* PtrType;
PassRefPtr() : m_ptr(nullptr) { }
PassRefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); }
// It somewhat breaks the type system to allow transfer of ownership out of
// a const PassRefPtr. However, it makes it much easier to work with PassRefPtr
// temporaries, and we don't have a need to use real const PassRefPtrs anyway.
PassRefPtr(const PassRefPtr& o) : m_ptr(o.leakRef()) { }
template<typename U> PassRefPtr(const PassRefPtr<U>& o) : m_ptr(o.leakRef()) { }
ALWAYS_INLINE ~PassRefPtr() { derefIfNotNull(std::exchange(m_ptr, nullptr)); }
template<typename U> PassRefPtr(const RefPtr<U>&);
template<typename U> PassRefPtr(Ref<U>&& reference) : m_ptr(&reference.leakRef()) { }
T* get() const { return m_ptr; }
T* leakRef() const WARN_UNUSED_RETURN;
T& operator*() const { return *m_ptr; }
T* operator->() const { return m_ptr; }
bool operator!() const { return !m_ptr; }
// This conversion operator allows implicit conversion to bool but not to other integer types.
typedef T* (PassRefPtr::*UnspecifiedBoolType);
operator UnspecifiedBoolType() const { return m_ptr ? &PassRefPtr::m_ptr : nullptr; }
friend PassRefPtr adoptRef<T>(T*);
private:
PassRefPtr& operator=(const PassRefPtr&) = delete;
enum AdoptTag { Adopt };
PassRefPtr(T* ptr, AdoptTag) : m_ptr(ptr) { }
mutable T* m_ptr;
};
template<typename T> template<typename U> inline PassRefPtr<T>::PassRefPtr(const RefPtr<U>& o)
: m_ptr(o.get())
{
T* ptr = m_ptr;
refIfNotNull(ptr);
}
template<typename T> inline T* PassRefPtr<T>::leakRef() const
{
return std::exchange(m_ptr, nullptr);
}
template<typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, const PassRefPtr<U>& b)
{
return a.get() == b.get();
}
template<typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, const RefPtr<U>& b)
{
return a.get() == b.get();
}
template<typename T, typename U> inline bool operator==(const RefPtr<T>& a, const PassRefPtr<U>& b)
{
return a.get() == b.get();
}
template<typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, U* b)
{
return a.get() == b;
}
template<typename T, typename U> inline bool operator==(T* a, const PassRefPtr<U>& b)
{
return a == b.get();
}
template<typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, const PassRefPtr<U>& b)
{
return a.get() != b.get();
}
template<typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, const RefPtr<U>& b)
{
return a.get() != b.get();
}
template<typename T, typename U> inline bool operator!=(const RefPtr<T>& a, const PassRefPtr<U>& b)
{
return a.get() != b.get();
}
template<typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, U* b)
{
return a.get() != b;
}
template<typename T, typename U> inline bool operator!=(T* a, const PassRefPtr<U>& b)
{
return a != b.get();
}
template<typename T> inline PassRefPtr<T> adoptRef(T* p)
{
adopted(p);
return PassRefPtr<T>(p, PassRefPtr<T>::Adopt);
}
template<typename T, typename U> inline PassRefPtr<T> static_pointer_cast(const PassRefPtr<U>& p)
{
return adoptRef(static_cast<T*>(p.leakRef()));
}
template <typename T> struct IsSmartPtr<PassRefPtr<T>> {
static const bool value = true;
};
} // namespace WTF
using WTF::PassRefPtr;
using WTF::adoptRef;
using WTF::static_pointer_cast;
#endif // WTF_PassRefPtr_h
|
