1/*
2 * Copyright (C) 2010 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef WTF_PassOwnArrayPtr_h
27#define WTF_PassOwnArrayPtr_h
28
29#include "Assertions.h"
30#include "NullPtr.h"
31#include "TypeTraits.h"
32
33namespace WTF {
34
35template<typename T> class OwnArrayPtr;
36template<typename T> class PassOwnArrayPtr;
37template<typename T> PassOwnArrayPtr<T> adoptArrayPtr(T*);
38template<typename T> void deleteOwnedArrayPtr(T* ptr);
39
40template<typename T> class PassOwnArrayPtr {
41public:
42    typedef T* PtrType;
43
44    PassOwnArrayPtr() : m_ptr(0) { }
45
46#if !defined(LOOSE_PASS_OWN_PTR) || !HAVE(NULLPTR)
47    PassOwnArrayPtr(std::nullptr_t) : m_ptr(0) { }
48#endif
49
50    // It somewhat breaks the type system to allow transfer of ownership out of
51    // a const PassOwnArrayPtr. However, it makes it much easier to work with PassOwnArrayPtr
52    // temporaries, and we don't have a need to use real const PassOwnArrayPtrs anyway.
53    PassOwnArrayPtr(const PassOwnArrayPtr& o) : m_ptr(o.leakPtr()) { }
54    template<typename U> PassOwnArrayPtr(const PassOwnArrayPtr<U>& o) : m_ptr(o.leakPtr()) { }
55
56    ~PassOwnArrayPtr() { deleteOwnedArrayPtr(m_ptr); }
57
58    PtrType get() const { return m_ptr; }
59
60    void clear();
61    PtrType leakPtr() const WARN_UNUSED_RETURN;
62
63    T& operator*() const { ASSERT(m_ptr); return *m_ptr; }
64    PtrType operator->() const { ASSERT(m_ptr); return m_ptr; }
65
66    bool operator!() const { return !m_ptr; }
67
68    // This conversion operator allows implicit conversion to bool but not to other integer types.
69#if COMPILER(WINSCW)
70    operator bool() const { return m_ptr; }
71#else
72    typedef PtrType PassOwnArrayPtr::*UnspecifiedBoolType;
73    operator UnspecifiedBoolType() const { return m_ptr ? &PassOwnArrayPtr::m_ptr : 0; }
74#endif
75
76    PassOwnArrayPtr& operator=(const PassOwnArrayPtr<T>&);
77#if !defined(LOOSE_PASS_OWN_ARRAY_PTR) || !HAVE(NULLPTR)
78    PassOwnArrayPtr& operator=(std::nullptr_t) { clear(); return *this; }
79#endif
80    template<typename U> PassOwnArrayPtr& operator=(const PassOwnArrayPtr<U>&);
81
82    template<typename U> friend PassOwnArrayPtr<U> adoptArrayPtr(U*);
83
84#ifdef LOOSE_PASS_OWN_ARRAY_PTR
85    PassOwnArrayPtr(PtrType ptr) : m_ptr(ptr) { }
86    PassOwnArrayPtr& operator=(PtrType);
87#endif
88
89private:
90#ifndef LOOSE_PASS_OWN_ARRAY_PTR
91    explicit PassOwnArrayPtr(PtrType ptr) : m_ptr(ptr) { }
92#endif
93
94    mutable PtrType m_ptr;
95};
96
97template<typename T> inline void PassOwnArrayPtr<T>::clear()
98{
99    PtrType ptr = m_ptr;
100    m_ptr = 0;
101    deleteOwnedArrayPtr(ptr);
102}
103
104template<typename T> inline typename PassOwnArrayPtr<T>::PtrType PassOwnArrayPtr<T>::leakPtr() const
105{
106    PtrType ptr = m_ptr;
107    m_ptr = 0;
108    return ptr;
109}
110
111#ifdef LOOSE_PASS_OWN_ARRAY_PTR
112template<typename T> inline PassOwnArrayPtr<T>& PassOwnArrayPtr<T>::operator=(PtrType optr)
113{
114    PtrType ptr = m_ptr;
115    m_ptr = optr;
116    ASSERT(!ptr || m_ptr != ptr);
117    if (ptr)
118        deleteOwnedArrayPtr(ptr);
119    return *this;
120}
121#endif
122
123template<typename T> inline PassOwnArrayPtr<T>& PassOwnArrayPtr<T>::operator=(const PassOwnArrayPtr<T>& optr)
124{
125    PtrType ptr = m_ptr;
126    m_ptr = optr.leakPtr();
127    ASSERT(!ptr || m_ptr != ptr);
128    if (ptr)
129        deleteOwnedArrayPtr(ptr);
130    return *this;
131}
132
133template<typename T> template<typename U> inline PassOwnArrayPtr<T>& PassOwnArrayPtr<T>::operator=(const PassOwnArrayPtr<U>& optr)
134{
135    PtrType ptr = m_ptr;
136    m_ptr = optr.leakPtr();
137    ASSERT(!ptr || m_ptr != ptr);
138    if (ptr)
139        deleteOwnedArrayPtr(ptr);
140    return *this;
141}
142
143template<typename T, typename U> inline bool operator==(const PassOwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b)
144{
145    return a.get() == b.get();
146}
147
148template<typename T, typename U> inline bool operator==(const PassOwnArrayPtr<T>& a, const OwnArrayPtr<U>& b)
149{
150    return a.get() == b.get();
151}
152
153template<typename T, typename U> inline bool operator==(const OwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b)
154{
155    return a.get() == b.get();
156}
157
158template<typename T, typename U> inline bool operator==(const PassOwnArrayPtr<T>& a, U* b)
159{
160    return a.get() == b;
161}
162
163template<typename T, typename U> inline bool operator==(T* a, const PassOwnArrayPtr<U>& b)
164{
165    return a == b.get();
166}
167
168template<typename T, typename U> inline bool operator!=(const PassOwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b)
169{
170    return a.get() != b.get();
171}
172
173template<typename T, typename U> inline bool operator!=(const PassOwnArrayPtr<T>& a, const OwnArrayPtr<U>& b)
174{
175    return a.get() != b.get();
176}
177
178template<typename T, typename U> inline bool operator!=(const OwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b)
179{
180    return a.get() != b.get();
181}
182
183template<typename T, typename U> inline bool operator!=(const PassOwnArrayPtr<T>& a, U* b)
184{
185    return a.get() != b;
186}
187
188template<typename T, typename U> inline bool operator!=(T* a, const PassOwnArrayPtr<U>& b)
189{
190    return a != b.get();
191}
192
193template<typename T> inline PassOwnArrayPtr<T> adoptArrayPtr(T* ptr)
194{
195    return PassOwnArrayPtr<T>(ptr);
196}
197
198template<typename T> inline void deleteOwnedArrayPtr(T* ptr)
199{
200    typedef char known[sizeof(T) ? 1 : -1];
201    if (sizeof(known))
202        delete [] ptr;
203}
204
205template<typename T, typename U> inline PassOwnArrayPtr<T> static_pointer_cast(const PassOwnArrayPtr<U>& p)
206{
207    return adoptArrayPtr(static_cast<T*>(p.leakPtr()));
208}
209
210template<typename T, typename U> inline PassOwnArrayPtr<T> const_pointer_cast(const PassOwnArrayPtr<U>& p)
211{
212    return adoptArrayPtr(const_cast<T*>(p.leakPtr()));
213}
214
215template<typename T> inline T* getPtr(const PassOwnArrayPtr<T>& p)
216{
217    return p.get();
218}
219
220} // namespace WTF
221
222using WTF::PassOwnArrayPtr;
223using WTF::adoptArrayPtr;
224using WTF::const_pointer_cast;
225using WTF::static_pointer_cast;
226
227#endif // WTF_PassOwnArrayPtr_h
228