1/*
2 * Copyright (C) 2016 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. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include <memory>
29#include <wtf/Assertions.h>
30
31namespace WTF {
32
33template<typename T> class UniqueRef;
34
35template<typename T, class... Args>
36UniqueRef<T> makeUniqueRef(Args&&... args)
37{
38 return UniqueRef<T>(*new T(std::forward<Args>(args)...));
39}
40
41template<typename T>
42class UniqueRef {
43public:
44 template <typename U>
45 UniqueRef(UniqueRef<U>&& other)
46 : m_ref(WTFMove(other.m_ref))
47 {
48 ASSERT(m_ref);
49 }
50
51 T& get() { ASSERT(m_ref); return *m_ref; }
52 const T& get() const { ASSERT(m_ref); return *m_ref; }
53
54 T* operator&() { ASSERT(m_ref); return m_ref.get(); }
55 const T* operator&() const { ASSERT(m_ref); return m_ref.get(); }
56
57 T* operator->() { ASSERT(m_ref); return m_ref.get(); }
58 const T* operator->() const { ASSERT(m_ref); return m_ref.get(); }
59
60 operator T&() { ASSERT(m_ref); return *m_ref; }
61 operator const T&() const { ASSERT(m_ref); return *m_ref; }
62
63private:
64 template<class U, class... Args> friend UniqueRef<U> makeUniqueRef(Args&&...);
65 template<class U> friend class UniqueRef;
66
67 UniqueRef(T& other)
68 : m_ref(&other)
69 {
70 ASSERT(m_ref);
71 }
72
73 std::unique_ptr<T> m_ref;
74};
75
76} // namespace WTF
77
78using WTF::UniqueRef;
79using WTF::makeUniqueRef;
80