1/*
2 *  Copyright (C) 2006, 2007, 2008, 2009 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 WTF_OwnPtr_h
22#define WTF_OwnPtr_h
23
24#include "Assertions.h"
25#include "Noncopyable.h"
26#include "OwnPtrCommon.h"
27#include "TypeTraits.h"
28#include <algorithm>
29#include <memory>
30
31namespace WTF {
32
33    // Unlike most of our smart pointers, OwnPtr can take either the pointer type or the pointed-to type.
34
35    template <typename T> class PassOwnPtr;
36
37    template <typename T> class OwnPtr : public Noncopyable {
38    public:
39        typedef typename RemovePointer<T>::Type ValueType;
40        typedef ValueType* PtrType;
41
42        explicit OwnPtr(PtrType ptr = 0) : m_ptr(ptr) { }
43        OwnPtr(std::auto_ptr<ValueType> autoPtr) : m_ptr(autoPtr.release()) { }
44        // See comment in PassOwnPtr.h for why this takes a const reference.
45        template <typename U> OwnPtr(const PassOwnPtr<U>& o);
46
47        // This copy constructor is used implicitly by gcc when it generates
48        // transients for assigning a PassOwnPtr<T> object to a stack-allocated
49        // OwnPtr<T> object.  It should never be called explicitly and gcc
50        // should optimize away the constructor when generating code.
51        OwnPtr(const OwnPtr<ValueType>& o);
52
53        ~OwnPtr() { deleteOwnedPtr(m_ptr); }
54
55        PtrType get() const { return m_ptr; }
56        PtrType release() { PtrType ptr = m_ptr; m_ptr = 0; return ptr; }
57
58        // FIXME: This should be renamed to adopt.
59        void set(PtrType ptr) { ASSERT(!ptr || m_ptr != ptr); deleteOwnedPtr(m_ptr); m_ptr = ptr; }
60
61        void adopt(std::auto_ptr<ValueType> autoPtr) { ASSERT(!autoPtr.get() || m_ptr != autoPtr.get()); deleteOwnedPtr(m_ptr); m_ptr = autoPtr.release(); }
62
63        void clear() { deleteOwnedPtr(m_ptr); m_ptr = 0; }
64
65        ValueType& operator*() const { ASSERT(m_ptr); return *m_ptr; }
66        PtrType operator->() const { ASSERT(m_ptr); 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 PtrType OwnPtr::*UnspecifiedBoolType;
72        operator UnspecifiedBoolType() const { return m_ptr ? &OwnPtr::m_ptr : 0; }
73
74        OwnPtr& operator=(const PassOwnPtr<T>&);
75        template <typename U> OwnPtr& operator=(const PassOwnPtr<U>&);
76
77        void swap(OwnPtr& o) { std::swap(m_ptr, o.m_ptr); }
78
79    private:
80        PtrType m_ptr;
81    };
82
83    template <typename T> template <typename U> inline OwnPtr<T>::OwnPtr(const PassOwnPtr<U>& o)
84        : m_ptr(o.release())
85    {
86    }
87
88    template <typename T> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<T>& o)
89    {
90        T* ptr = m_ptr;
91        m_ptr = o.release();
92        ASSERT(!ptr || m_ptr != ptr);
93        if (ptr)
94            deleteOwnedPtr(ptr);
95        return *this;
96    }
97
98    template <typename T> template <typename U> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<U>& o)
99    {
100        T* ptr = m_ptr;
101        m_ptr = o.release();
102        ASSERT(!ptr || m_ptr != ptr);
103        if (ptr)
104            deleteOwnedPtr(ptr);
105        return *this;
106    }
107
108    template <typename T> inline void swap(OwnPtr<T>& a, OwnPtr<T>& b)
109    {
110        a.swap(b);
111    }
112
113    template <typename T, typename U> inline bool operator==(const OwnPtr<T>& a, U* b)
114    {
115        return a.get() == b;
116    }
117
118    template <typename T, typename U> inline bool operator==(T* a, const OwnPtr<U>& b)
119    {
120        return a == b.get();
121    }
122
123    template <typename T, typename U> inline bool operator!=(const OwnPtr<T>& a, U* b)
124    {
125        return a.get() != b;
126    }
127
128    template <typename T, typename U> inline bool operator!=(T* a, const OwnPtr<U>& b)
129    {
130        return a != b.get();
131    }
132
133    template <typename T> inline typename OwnPtr<T>::PtrType getPtr(const OwnPtr<T>& p)
134    {
135        return p.get();
136    }
137
138} // namespace WTF
139
140using WTF::OwnPtr;
141
142#endif // WTF_OwnPtr_h
143