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 
32 namespace 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__
adoptNSReference(id ptr)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 
RetainPtr()55         RetainPtr() : m_ptr(0) {}
RetainPtr(PtrType ptr)56         RetainPtr(PtrType ptr) : m_ptr(ptr) { if (ptr) CFRetain(ptr); }
57 
RetainPtr(AdoptCFTag,PtrType ptr)58         RetainPtr(AdoptCFTag, PtrType ptr) : m_ptr(ptr) { }
RetainPtr(AdoptNSTag,PtrType ptr)59         RetainPtr(AdoptNSTag, PtrType ptr) : m_ptr(ptr) { adoptNSReference(ptr); }
60 
RetainPtr(const RetainPtr & o)61         RetainPtr(const RetainPtr& o) : m_ptr(o.m_ptr) { if (PtrType ptr = m_ptr) CFRetain(ptr); }
62 
~RetainPtr()63         ~RetainPtr() { if (PtrType ptr = m_ptr) CFRelease(ptr); }
64 
RetainPtr(const RetainPtr<U> & o)65         template <typename U> RetainPtr(const RetainPtr<U>& o) : m_ptr(o.get()) { if (PtrType ptr = m_ptr) CFRetain(ptr); }
66 
get()67         PtrType get() const { return m_ptr; }
68 
releaseRef()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;
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 
adoptCF(PtrType optr)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 
adoptNS(PtrType optr)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 
swap(RetainPtr<T> & o)157     template <class T> inline void RetainPtr<T>::swap(RetainPtr<T>& o)
158     {
159         std::swap(m_ptr, o.m_ptr);
160     }
161 
swap(RetainPtr<T> & a,RetainPtr<T> & b)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 
199 using WTF::AdoptCF;
200 using WTF::AdoptNS;
201 using WTF::RetainPtr;
202 
203 #endif // WTF_RetainPtr_h
204