1/*
2 *  Copyright (C) 2005, 2006, 2007, 2008 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#ifndef RetainPtr_h
22#define RetainPtr_h
23
24#include "TypeTraits.h"
25#include <algorithm>
26#include <CoreFoundation/CoreFoundation.h>
27
28#ifdef __OBJC__
29#import <Foundation/Foundation.h>
30#endif
31
32namespace WTF {
33
34    // Unlike most most of our smart pointers, RetainPtr can take either the pointer type or the pointed-to type,
35    // so both RetainPtr<NSDictionary> and RetainPtr<CFDictionaryRef> will work.
36
37    enum AdoptCFTag { AdoptCF };
38    enum AdoptNSTag { AdoptNS };
39
40#ifdef __OBJC__
41    inline void adoptNSReference(id ptr)
42    {
43        if (ptr) {
44            CFRetain(ptr);
45            [ptr release];
46        }
47    }
48#endif
49
50    template <typename T> class RetainPtr {
51    public:
52        typedef typename RemovePointer<T>::Type ValueType;
53        typedef ValueType* PtrType;
54
55        RetainPtr() : m_ptr(0) {}
56        RetainPtr(PtrType ptr) : m_ptr(ptr) { if (ptr) CFRetain(ptr); }
57
58        RetainPtr(AdoptCFTag, PtrType ptr) : m_ptr(ptr) { }
59        RetainPtr(AdoptNSTag, PtrType ptr) : m_ptr(ptr) { adoptNSReference(ptr); }
60
61        RetainPtr(const RetainPtr& o) : m_ptr(o.m_ptr) { if (PtrType ptr = m_ptr) CFRetain(ptr); }
62
63        ~RetainPtr() { if (PtrType ptr = m_ptr) CFRelease(ptr); }
64
65        template <typename U> RetainPtr(const RetainPtr<U>& o) : m_ptr(o.get()) { if (PtrType ptr = m_ptr) CFRetain(ptr); }
66
67        PtrType get() const { return m_ptr; }
68
69        PtrType releaseRef() { PtrType tmp = m_ptr; m_ptr = 0; return tmp; }
70
71        PtrType operator->() const { return m_ptr; }
72
73        bool operator!() const { return !m_ptr; }
74
75        // This conversion operator allows implicit conversion to bool but not to other integer types.
76        typedef PtrType RetainPtr::*UnspecifiedBoolType;
77        operator UnspecifiedBoolType() const { return m_ptr ? &RetainPtr::m_ptr : 0; }
78
79        RetainPtr& operator=(const RetainPtr&);
80        template <typename U> RetainPtr& operator=(const RetainPtr<U>&);
81        RetainPtr& operator=(PtrType);
82        template <typename U> RetainPtr& operator=(U*);
83
84        void adoptCF(PtrType);
85        void adoptNS(PtrType);
86
87        void swap(RetainPtr&);
88
89    private:
90        PtrType m_ptr;
91    };
92
93    template <typename T> inline RetainPtr<T>& RetainPtr<T>::operator=(const RetainPtr<T>& o)
94    {
95        PtrType optr = o.get();
96        if (optr)
97            CFRetain(optr);
98        PtrType ptr = m_ptr;
99        m_ptr = optr;
100        if (ptr)
101            CFRelease(ptr);
102        return *this;
103    }
104
105    template <typename T> template <typename U> inline RetainPtr<T>& RetainPtr<T>::operator=(const RetainPtr<U>& o)
106    {
107        PtrType optr = o.get();
108        if (optr)
109            CFRetain(optr);
110        PtrType ptr = m_ptr;
111        m_ptr = optr;
112        if (ptr)
113            CFRelease(ptr);
114        return *this;
115    }
116
117    template <typename T> inline RetainPtr<T>& RetainPtr<T>::operator=(PtrType optr)
118    {
119        if (optr)
120            CFRetain(optr);
121        PtrType ptr = m_ptr;
122        m_ptr = optr;
123        if (ptr)
124            CFRelease(ptr);
125        return *this;
126    }
127
128    template <typename T> inline void RetainPtr<T>::adoptCF(PtrType optr)
129    {
130        PtrType ptr = m_ptr;
131        m_ptr = optr;
132        if (ptr)
133            CFRelease(ptr);
134    }
135
136    template <typename T> inline void RetainPtr<T>::adoptNS(PtrType optr)
137    {
138        adoptNSReference(optr);
139
140        PtrType ptr = m_ptr;
141        m_ptr = optr;
142        if (ptr)
143            CFRelease(ptr);
144    }
145
146    template <typename T> template <typename U> inline RetainPtr<T>& RetainPtr<T>::operator=(U* optr)
147    {
148        if (optr)
149            CFRetain(optr);
150        PtrType ptr = m_ptr;
151        m_ptr = optr;
152        if (ptr)
153            CFRelease(ptr);
154        return *this;
155    }
156
157    template <class T> inline void RetainPtr<T>::swap(RetainPtr<T>& o)
158    {
159        std::swap(m_ptr, o.m_ptr);
160    }
161
162    template <class T> inline void swap(RetainPtr<T>& a, RetainPtr<T>& b)
163    {
164        a.swap(b);
165    }
166
167    template <typename T, typename U> inline bool operator==(const RetainPtr<T>& a, const RetainPtr<U>& b)
168    {
169        return a.get() == b.get();
170    }
171
172    template <typename T, typename U> inline bool operator==(const RetainPtr<T>& a, U* b)
173    {
174        return a.get() == b;
175    }
176
177    template <typename T, typename U> inline bool operator==(T* a, const RetainPtr<U>& b)
178    {
179        return a == b.get();
180    }
181
182    template <typename T, typename U> inline bool operator!=(const RetainPtr<T>& a, const RetainPtr<U>& b)
183    {
184        return a.get() != b.get();
185    }
186
187    template <typename T, typename U> inline bool operator!=(const RetainPtr<T>& a, U* b)
188    {
189        return a.get() != b;
190    }
191
192    template <typename T, typename U> inline bool operator!=(T* a, const RetainPtr<U>& b)
193    {
194        return a != b.get();
195    }
196
197} // namespace WTF
198
199using WTF::AdoptCF;
200using WTF::AdoptNS;
201using WTF::RetainPtr;
202
203#endif // WTF_RetainPtr_h
204