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1 // Copyright 2016 PDFium Authors. All rights reserved. | 1 // Copyright 2016 PDFium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef CORE_FXCRT_CFX_MAYBE_OWNED_H_ | 5 #ifndef CORE_FXCRT_CFX_MAYBE_OWNED_H_ |
6 #define CORE_FXCRT_CFX_MAYBE_OWNED_H_ | 6 #define CORE_FXCRT_CFX_MAYBE_OWNED_H_ |
7 | 7 |
8 #include <algorithm> | 8 #include <algorithm> |
9 #include <memory> | 9 #include <memory> |
10 #include <utility> | 10 #include <utility> |
11 | 11 |
12 #include "core/fxcrt/fx_memory.h" | 12 #include "core/fxcrt/fx_memory.h" |
13 #include "core/fxcrt/fx_system.h" | 13 #include "core/fxcrt/fx_system.h" |
14 | 14 |
15 // A template that can hold either owned or unowned references, and cleans up | 15 // A template that can hold either owned or unowned references, and cleans up |
16 // appropriately. Possibly the most pernicious anti-pattern imaginable, but | 16 // appropriately. Possibly the most pernicious anti-pattern imaginable, but |
17 // it crops up throughout the codebase due to a desire to avoid copying-in | 17 // it crops up throughout the codebase due to a desire to avoid copying-in |
18 // objects or data. | 18 // objects or data. |
19 template <typename T, typename D = std::default_delete<T>> | 19 template <typename T, typename D = std::default_delete<T>> |
20 class CFX_MaybeOwned { | 20 class CFX_MaybeOwned { |
21 public: | 21 public: |
22 CFX_MaybeOwned() : m_pObj(nullptr) {} | 22 CFX_MaybeOwned() : m_pObj(nullptr) {} |
23 explicit CFX_MaybeOwned(T* ptr) : m_pObj(ptr) {} | 23 explicit CFX_MaybeOwned(T* ptr) : m_pObj(ptr) {} |
24 explicit CFX_MaybeOwned(std::unique_ptr<T> ptr) | 24 explicit CFX_MaybeOwned(std::unique_ptr<T, D> ptr) |
25 : m_pOwnedObj(std::move(ptr)), m_pObj(m_pOwnedObj.get()) {} | 25 : m_pOwnedObj(std::move(ptr)), m_pObj(m_pOwnedObj.get()) {} |
26 | 26 |
27 CFX_MaybeOwned(const CFX_MaybeOwned& that) = delete; | 27 CFX_MaybeOwned(const CFX_MaybeOwned& that) = delete; |
28 CFX_MaybeOwned(CFX_MaybeOwned&& that) | 28 CFX_MaybeOwned(CFX_MaybeOwned&& that) |
29 : m_pOwnedObj(that.m_pOwnedObj.release()), m_pObj(that.m_pObj) { | 29 : m_pOwnedObj(that.m_pOwnedObj.release()), m_pObj(that.m_pObj) { |
30 that.m_pObj = nullptr; | 30 that.m_pObj = nullptr; |
31 } | 31 } |
32 | 32 |
33 void Reset(std::unique_ptr<T> ptr) { | 33 void Reset(std::unique_ptr<T, D> ptr) { |
34 m_pOwnedObj = std::move(ptr); | 34 m_pOwnedObj = std::move(ptr); |
35 m_pObj = m_pOwnedObj.get(); | 35 m_pObj = m_pOwnedObj.get(); |
36 } | 36 } |
37 void Reset(T* ptr = nullptr) { | 37 void Reset(T* ptr = nullptr) { |
38 m_pOwnedObj.reset(); | 38 m_pOwnedObj.reset(); |
39 m_pObj = ptr; | 39 m_pObj = ptr; |
40 } | 40 } |
41 | 41 |
42 bool IsOwned() const { return !!m_pOwnedObj; } | 42 bool IsOwned() const { return !!m_pOwnedObj; } |
43 T* Get() const { return m_pObj; } | 43 T* Get() const { return m_pObj; } |
44 std::unique_ptr<T> Release() { | 44 std::unique_ptr<T, D> Release() { |
45 ASSERT(IsOwned()); | 45 ASSERT(IsOwned()); |
46 return std::move(m_pOwnedObj); | 46 return std::move(m_pOwnedObj); |
47 } | 47 } |
48 | 48 |
49 CFX_MaybeOwned& operator=(const CFX_MaybeOwned& that) = delete; | 49 CFX_MaybeOwned& operator=(const CFX_MaybeOwned& that) = delete; |
50 CFX_MaybeOwned& operator=(CFX_MaybeOwned&& that) { | 50 CFX_MaybeOwned& operator=(CFX_MaybeOwned&& that) { |
51 m_pOwnedObj = std::move(that.m_pOwnedObj); | 51 m_pOwnedObj = std::move(that.m_pOwnedObj); |
52 m_pObj = that.m_pObj; | 52 m_pObj = that.m_pObj; |
53 that.m_pObj = nullptr; | 53 that.m_pObj = nullptr; |
54 return *this; | 54 return *this; |
55 } | 55 } |
56 CFX_MaybeOwned& operator=(T* ptr) { | 56 CFX_MaybeOwned& operator=(T* ptr) { |
57 Reset(ptr); | 57 Reset(ptr); |
58 return *this; | 58 return *this; |
59 } | 59 } |
60 CFX_MaybeOwned& operator=(std::unique_ptr<T> ptr) { | 60 CFX_MaybeOwned& operator=(std::unique_ptr<T, D> ptr) { |
61 Reset(std::move(ptr)); | 61 Reset(std::move(ptr)); |
62 return *this; | 62 return *this; |
63 } | 63 } |
64 | 64 |
65 bool operator==(const CFX_MaybeOwned& that) const { | 65 bool operator==(const CFX_MaybeOwned& that) const { |
66 return Get() == that.Get(); | 66 return Get() == that.Get(); |
67 } | 67 } |
68 bool operator==(const std::unique_ptr<T>& ptr) const { | 68 bool operator==(const std::unique_ptr<T, D>& ptr) const { |
69 return Get() == ptr.get(); | 69 return Get() == ptr.get(); |
70 } | 70 } |
71 bool operator==(T* ptr) const { return Get() == ptr; } | 71 bool operator==(T* ptr) const { return Get() == ptr; } |
72 | 72 |
73 bool operator!=(const CFX_MaybeOwned& that) const { return !(*this == that); } | 73 bool operator!=(const CFX_MaybeOwned& that) const { return !(*this == that); } |
74 bool operator!=(const std::unique_ptr<T> ptr) const { | 74 bool operator!=(const std::unique_ptr<T, D> ptr) const { |
75 return !(*this == ptr); | 75 return !(*this == ptr); |
76 } | 76 } |
77 bool operator!=(T* ptr) const { return !(*this == ptr); } | 77 bool operator!=(T* ptr) const { return !(*this == ptr); } |
78 | 78 |
79 explicit operator bool() const { return !!m_pObj; } | 79 explicit operator bool() const { return !!m_pObj; } |
80 T& operator*() const { return *m_pObj; } | 80 T& operator*() const { return *m_pObj; } |
81 T* operator->() const { return m_pObj; } | 81 T* operator->() const { return m_pObj; } |
82 | 82 |
83 private: | 83 private: |
84 std::unique_ptr<T, D> m_pOwnedObj; | 84 std::unique_ptr<T, D> m_pOwnedObj; |
85 T* m_pObj; | 85 T* m_pObj; |
86 }; | 86 }; |
87 | 87 |
88 #endif // CORE_FXCRT_CFX_MAYBE_OWNED_H_ | 88 #endif // CORE_FXCRT_CFX_MAYBE_OWNED_H_ |
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