1 //===- CustomizableOptional.h - Optional with custom storage ----*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #ifndef CLANG_BASIC_CUSTOMIZABLEOPTIONAL_H
10 #define CLANG_BASIC_CUSTOMIZABLEOPTIONAL_H
11
12 #include "llvm/ADT/Hashing.h"
13 #include "llvm/Support/Compiler.h"
14 #include "llvm/Support/type_traits.h"
15 #include <cassert>
16 #include <new>
17 #include <optional>
18 #include <utility>
19
20 namespace clang {
21
22 namespace optional_detail {
23 template <typename> class OptionalStorage;
24 } // namespace optional_detail
25
26 // Optional type which internal storage can be specialized by providing
27 // OptionalStorage. The interface follows std::optional.
28 template <typename T> class CustomizableOptional {
29 optional_detail::OptionalStorage<T> Storage;
30
31 public:
32 using value_type = T;
33
34 constexpr CustomizableOptional() = default;
CustomizableOptional(std::nullopt_t)35 constexpr CustomizableOptional(std::nullopt_t) {}
36
CustomizableOptional(const T & y)37 constexpr CustomizableOptional(const T &y) : Storage(std::in_place, y) {}
38 constexpr CustomizableOptional(const CustomizableOptional &O) = default;
39
CustomizableOptional(T && y)40 constexpr CustomizableOptional(T &&y)
41 : Storage(std::in_place, std::move(y)) {}
42 constexpr CustomizableOptional(CustomizableOptional &&O) = default;
43
44 template <typename... ArgTypes>
CustomizableOptional(std::in_place_t,ArgTypes &&...Args)45 constexpr CustomizableOptional(std::in_place_t, ArgTypes &&...Args)
46 : Storage(std::in_place, std::forward<ArgTypes>(Args)...) {}
47
48 // Allow conversion from std::optional<T>.
CustomizableOptional(const std::optional<T> & y)49 constexpr CustomizableOptional(const std::optional<T> &y)
50 : CustomizableOptional(y ? *y : CustomizableOptional()) {}
CustomizableOptional(std::optional<T> && y)51 constexpr CustomizableOptional(std::optional<T> &&y)
52 : CustomizableOptional(y ? std::move(*y) : CustomizableOptional()) {}
53
54 CustomizableOptional &operator=(T &&y) {
55 Storage = std::move(y);
56 return *this;
57 }
58 CustomizableOptional &operator=(CustomizableOptional &&O) = default;
59
60 /// Create a new object by constructing it in place with the given arguments.
emplace(ArgTypes &&...Args)61 template <typename... ArgTypes> void emplace(ArgTypes &&...Args) {
62 Storage.emplace(std::forward<ArgTypes>(Args)...);
63 }
64
65 CustomizableOptional &operator=(const T &y) {
66 Storage = y;
67 return *this;
68 }
69 CustomizableOptional &operator=(const CustomizableOptional &O) = default;
70
reset()71 void reset() { Storage.reset(); }
72
73 LLVM_DEPRECATED("Use &*X instead.", "&*X")
getPointer()74 constexpr const T *getPointer() const { return &Storage.value(); }
75 LLVM_DEPRECATED("Use &*X instead.", "&*X")
getPointer()76 T *getPointer() { return &Storage.value(); }
77 LLVM_DEPRECATED("std::optional::value is throwing. Use *X instead", "*X")
value()78 constexpr const T &value() const & { return Storage.value(); }
79 LLVM_DEPRECATED("std::optional::value is throwing. Use *X instead", "*X")
value()80 T &value() & { return Storage.value(); }
81
82 constexpr explicit operator bool() const { return has_value(); }
has_value()83 constexpr bool has_value() const { return Storage.has_value(); }
84 constexpr const T *operator->() const { return &Storage.value(); }
85 T *operator->() { return &Storage.value(); }
86 constexpr const T &operator*() const & { return Storage.value(); }
87 T &operator*() & { return Storage.value(); }
88
value_or(U && alt)89 template <typename U> constexpr T value_or(U &&alt) const & {
90 return has_value() ? operator*() : std::forward<U>(alt);
91 }
92
93 LLVM_DEPRECATED("std::optional::value is throwing. Use *X instead", "*X")
value()94 T &&value() && { return std::move(Storage.value()); }
95 T &&operator*() && { return std::move(Storage.value()); }
96
value_or(U && alt)97 template <typename U> T value_or(U &&alt) && {
98 return has_value() ? std::move(operator*()) : std::forward<U>(alt);
99 }
100
101 // Allow conversion to std::optional<T>.
102 explicit operator std::optional<T> &() const & {
103 return *this ? **this : std::optional<T>();
104 }
105 explicit operator std::optional<T> &&() const && {
106 return *this ? std::move(**this) : std::optional<T>();
107 }
108 };
109
110 template <typename T>
111 CustomizableOptional(const T &) -> CustomizableOptional<T>;
112
113 template <class T>
hash_value(const CustomizableOptional<T> & O)114 llvm::hash_code hash_value(const CustomizableOptional<T> &O) {
115 return O ? llvm::hash_combine(true, *O) : llvm::hash_value(false);
116 }
117
118 template <typename T, typename U>
119 constexpr bool operator==(const CustomizableOptional<T> &X,
120 const CustomizableOptional<U> &Y) {
121 if (X && Y)
122 return *X == *Y;
123 return X.has_value() == Y.has_value();
124 }
125
126 template <typename T, typename U>
127 constexpr bool operator!=(const CustomizableOptional<T> &X,
128 const CustomizableOptional<U> &Y) {
129 return !(X == Y);
130 }
131
132 template <typename T, typename U>
133 constexpr bool operator<(const CustomizableOptional<T> &X,
134 const CustomizableOptional<U> &Y) {
135 if (X && Y)
136 return *X < *Y;
137 return X.has_value() < Y.has_value();
138 }
139
140 template <typename T, typename U>
141 constexpr bool operator<=(const CustomizableOptional<T> &X,
142 const CustomizableOptional<U> &Y) {
143 return !(Y < X);
144 }
145
146 template <typename T, typename U>
147 constexpr bool operator>(const CustomizableOptional<T> &X,
148 const CustomizableOptional<U> &Y) {
149 return Y < X;
150 }
151
152 template <typename T, typename U>
153 constexpr bool operator>=(const CustomizableOptional<T> &X,
154 const CustomizableOptional<U> &Y) {
155 return !(X < Y);
156 }
157
158 template <typename T>
159 constexpr bool operator==(const CustomizableOptional<T> &X, std::nullopt_t) {
160 return !X;
161 }
162
163 template <typename T>
164 constexpr bool operator==(std::nullopt_t, const CustomizableOptional<T> &X) {
165 return X == std::nullopt;
166 }
167
168 template <typename T>
169 constexpr bool operator!=(const CustomizableOptional<T> &X, std::nullopt_t) {
170 return !(X == std::nullopt);
171 }
172
173 template <typename T>
174 constexpr bool operator!=(std::nullopt_t, const CustomizableOptional<T> &X) {
175 return X != std::nullopt;
176 }
177
178 template <typename T>
179 constexpr bool operator<(const CustomizableOptional<T> &, std::nullopt_t) {
180 return false;
181 }
182
183 template <typename T>
184 constexpr bool operator<(std::nullopt_t, const CustomizableOptional<T> &X) {
185 return X.has_value();
186 }
187
188 template <typename T>
189 constexpr bool operator<=(const CustomizableOptional<T> &X, std::nullopt_t) {
190 return !(std::nullopt < X);
191 }
192
193 template <typename T>
194 constexpr bool operator<=(std::nullopt_t, const CustomizableOptional<T> &X) {
195 return !(X < std::nullopt);
196 }
197
198 template <typename T>
199 constexpr bool operator>(const CustomizableOptional<T> &X, std::nullopt_t) {
200 return std::nullopt < X;
201 }
202
203 template <typename T>
204 constexpr bool operator>(std::nullopt_t, const CustomizableOptional<T> &X) {
205 return X < std::nullopt;
206 }
207
208 template <typename T>
209 constexpr bool operator>=(const CustomizableOptional<T> &X, std::nullopt_t) {
210 return std::nullopt <= X;
211 }
212
213 template <typename T>
214 constexpr bool operator>=(std::nullopt_t, const CustomizableOptional<T> &X) {
215 return X <= std::nullopt;
216 }
217
218 template <typename T>
219 constexpr bool operator==(const CustomizableOptional<T> &X, const T &Y) {
220 return X && *X == Y;
221 }
222
223 template <typename T>
224 constexpr bool operator==(const T &X, const CustomizableOptional<T> &Y) {
225 return Y && X == *Y;
226 }
227
228 template <typename T>
229 constexpr bool operator!=(const CustomizableOptional<T> &X, const T &Y) {
230 return !(X == Y);
231 }
232
233 template <typename T>
234 constexpr bool operator!=(const T &X, const CustomizableOptional<T> &Y) {
235 return !(X == Y);
236 }
237
238 template <typename T>
239 constexpr bool operator<(const CustomizableOptional<T> &X, const T &Y) {
240 return !X || *X < Y;
241 }
242
243 template <typename T>
244 constexpr bool operator<(const T &X, const CustomizableOptional<T> &Y) {
245 return Y && X < *Y;
246 }
247
248 template <typename T>
249 constexpr bool operator<=(const CustomizableOptional<T> &X, const T &Y) {
250 return !(Y < X);
251 }
252
253 template <typename T>
254 constexpr bool operator<=(const T &X, const CustomizableOptional<T> &Y) {
255 return !(Y < X);
256 }
257
258 template <typename T>
259 constexpr bool operator>(const CustomizableOptional<T> &X, const T &Y) {
260 return Y < X;
261 }
262
263 template <typename T>
264 constexpr bool operator>(const T &X, const CustomizableOptional<T> &Y) {
265 return Y < X;
266 }
267
268 template <typename T>
269 constexpr bool operator>=(const CustomizableOptional<T> &X, const T &Y) {
270 return !(X < Y);
271 }
272
273 template <typename T>
274 constexpr bool operator>=(const T &X, const CustomizableOptional<T> &Y) {
275 return !(X < Y);
276 }
277
278 } // namespace clang
279
280 #endif // CLANG_BASIC_CUSTOMIZABLEOPTIONAL_H
281