1/*
2 *  Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
3 *
4 *  This library is free software; you can redistribute it and/or
5 *  modify it under the terms of the GNU Library General Public
6 *  License as published by the Free Software Foundation; either
7 *  version 2 of the License, or (at your option) any later version.
8 *
9 *  This library is distributed in the hope that it will be useful,
10 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
11 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 *  Library General Public License for more details.
13 *
14 *  You should have received a copy of the GNU Library General Public License
15 *  along with this library; see the file COPYING.LIB.  If not, write to
16 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17 *  Boston, MA 02110-1301, USA.
18 *
19 */
20
21// RefPtr and PassRefPtr are documented at http://webkit.org/coding/RefPtr.html
22
23#ifndef WTF_RefPtr_h
24#define WTF_RefPtr_h
25
26#include <algorithm>
27#include "FastAllocBase.h"
28#include "PassRefPtr.h"
29
30namespace WTF {
31
32    enum PlacementNewAdoptType { PlacementNewAdopt };
33
34    template<typename T> class PassRefPtr;
35    template<typename T> class NonNullPassRefPtr;
36
37    enum HashTableDeletedValueType { HashTableDeletedValue };
38
39    template<typename T> class RefPtr {
40        WTF_MAKE_FAST_ALLOCATED;
41    public:
42        ALWAYS_INLINE RefPtr() : m_ptr(0) { }
43        ALWAYS_INLINE RefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); }
44        ALWAYS_INLINE RefPtr(const RefPtr& o) : m_ptr(o.m_ptr) { refIfNotNull(m_ptr); }
45        template<typename U> RefPtr(const RefPtr<U>& o) : m_ptr(o.get()) { refIfNotNull(m_ptr); }
46
47        // See comments in PassRefPtr.h for an explanation of why these takes const references.
48        template<typename U> RefPtr(const PassRefPtr<U>&);
49        template<typename U> RefPtr(const NonNullPassRefPtr<U>&);
50
51        // Special constructor for cases where we overwrite an object in place.
52        ALWAYS_INLINE RefPtr(PlacementNewAdoptType) { }
53
54        // Hash table deleted values, which are only constructed and never copied or destroyed.
55        RefPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { }
56        bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }
57
58        ALWAYS_INLINE ~RefPtr() { derefIfNotNull(m_ptr); }
59
60        T* get() const { return m_ptr; }
61
62        void clear();
63        PassRefPtr<T> release() { PassRefPtr<T> tmp = adoptRef(m_ptr); m_ptr = 0; return tmp; }
64
65        T& operator*() const { return *m_ptr; }
66        ALWAYS_INLINE T* operator->() const { return m_ptr; }
67
68        bool operator!() const { return !m_ptr; }
69
70        // This conversion operator allows implicit conversion to bool but not to other integer types.
71        typedef T* (RefPtr::*UnspecifiedBoolType);
72        operator UnspecifiedBoolType() const { return m_ptr ? &RefPtr::m_ptr : 0; }
73
74        RefPtr& operator=(const RefPtr&);
75        RefPtr& operator=(T*);
76        RefPtr& operator=(const PassRefPtr<T>&);
77        RefPtr& operator=(const NonNullPassRefPtr<T>&);
78#if !HAVE(NULLPTR)
79        RefPtr& operator=(std::nullptr_t) { clear(); return *this; }
80#endif
81        template<typename U> RefPtr& operator=(const RefPtr<U>&);
82        template<typename U> RefPtr& operator=(const PassRefPtr<U>&);
83        template<typename U> RefPtr& operator=(const NonNullPassRefPtr<U>&);
84
85        void swap(RefPtr&);
86
87        static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
88
89    private:
90        T* m_ptr;
91    };
92
93    template<typename T> template<typename U> inline RefPtr<T>::RefPtr(const PassRefPtr<U>& o)
94        : m_ptr(o.leakRef())
95    {
96    }
97
98    template<typename T> template<typename U> inline RefPtr<T>::RefPtr(const NonNullPassRefPtr<U>& o)
99        : m_ptr(o.leakRef())
100    {
101    }
102
103    template<typename T> inline void RefPtr<T>::clear()
104    {
105        T* ptr = m_ptr;
106        m_ptr = 0;
107        derefIfNotNull(ptr);
108    }
109
110    template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(const RefPtr<T>& o)
111    {
112        T* optr = o.get();
113        refIfNotNull(optr);
114        T* ptr = m_ptr;
115        m_ptr = optr;
116        derefIfNotNull(ptr);
117        return *this;
118    }
119
120    template<typename T> template<typename U> inline RefPtr<T>& RefPtr<T>::operator=(const RefPtr<U>& o)
121    {
122        T* optr = o.get();
123        refIfNotNull(optr);
124        T* ptr = m_ptr;
125        m_ptr = optr;
126        derefIfNotNull(ptr);
127        return *this;
128    }
129
130    template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(T* optr)
131    {
132        refIfNotNull(optr);
133        T* ptr = m_ptr;
134        m_ptr = optr;
135        derefIfNotNull(ptr);
136        return *this;
137    }
138
139    template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(const PassRefPtr<T>& o)
140    {
141        T* ptr = m_ptr;
142        m_ptr = o.leakRef();
143        derefIfNotNull(ptr);
144        return *this;
145    }
146
147    template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(const NonNullPassRefPtr<T>& o)
148    {
149        T* ptr = m_ptr;
150        m_ptr = o.leakRef();
151        derefIfNotNull(ptr);
152        return *this;
153    }
154
155    template<typename T> template<typename U> inline RefPtr<T>& RefPtr<T>::operator=(const PassRefPtr<U>& o)
156    {
157        T* ptr = m_ptr;
158        m_ptr = o.leakRef();
159        derefIfNotNull(ptr);
160        return *this;
161    }
162
163    template<typename T> template<typename U> inline RefPtr<T>& RefPtr<T>::operator=(const NonNullPassRefPtr<U>& o)
164    {
165        T* ptr = m_ptr;
166        m_ptr = o.leakRef();
167        derefIfNotNull(ptr);
168        return *this;
169    }
170
171    template<class T> inline void RefPtr<T>::swap(RefPtr<T>& o)
172    {
173        std::swap(m_ptr, o.m_ptr);
174    }
175
176    template<class T> inline void swap(RefPtr<T>& a, RefPtr<T>& b)
177    {
178        a.swap(b);
179    }
180
181    template<typename T, typename U> inline bool operator==(const RefPtr<T>& a, const RefPtr<U>& b)
182    {
183        return a.get() == b.get();
184    }
185
186    template<typename T, typename U> inline bool operator==(const RefPtr<T>& a, U* b)
187    {
188        return a.get() == b;
189    }
190
191    template<typename T, typename U> inline bool operator==(T* a, const RefPtr<U>& b)
192    {
193        return a == b.get();
194    }
195
196    template<typename T, typename U> inline bool operator!=(const RefPtr<T>& a, const RefPtr<U>& b)
197    {
198        return a.get() != b.get();
199    }
200
201    template<typename T, typename U> inline bool operator!=(const RefPtr<T>& a, U* b)
202    {
203        return a.get() != b;
204    }
205
206    template<typename T, typename U> inline bool operator!=(T* a, const RefPtr<U>& b)
207    {
208        return a != b.get();
209    }
210
211    template<typename T, typename U> inline RefPtr<T> static_pointer_cast(const RefPtr<U>& p)
212    {
213        return RefPtr<T>(static_cast<T*>(p.get()));
214    }
215
216    template<typename T, typename U> inline RefPtr<T> const_pointer_cast(const RefPtr<U>& p)
217    {
218        return RefPtr<T>(const_cast<T*>(p.get()));
219    }
220
221    template<typename T> inline T* getPtr(const RefPtr<T>& p)
222    {
223        return p.get();
224    }
225
226} // namespace WTF
227
228using WTF::RefPtr;
229using WTF::static_pointer_cast;
230using WTF::const_pointer_cast;
231
232#endif // WTF_RefPtr_h
233