OLD | NEW |
1 /* | 1 /* |
2 * Copyright 2015 The WebRTC Project Authors. All rights reserved. | 2 * Copyright 2015 The WebRTC Project Authors. All rights reserved. |
3 * | 3 * |
4 * Use of this source code is governed by a BSD-style license | 4 * Use of this source code is governed by a BSD-style license |
5 * that can be found in the LICENSE file in the root of the source | 5 * that can be found in the LICENSE file in the root of the source |
6 * tree. An additional intellectual property rights grant can be found | 6 * tree. An additional intellectual property rights grant can be found |
7 * in the file PATENTS. All contributing project authors may | 7 * in the file PATENTS. All contributing project authors may |
8 * be found in the AUTHORS file in the root of the source tree. | 8 * be found in the AUTHORS file in the root of the source tree. |
9 */ | 9 */ |
10 | 10 |
11 #ifndef WEBRTC_BASE_OPTIONAL_H_ | 11 #ifndef WEBRTC_BASE_OPTIONAL_H_ |
12 #define WEBRTC_BASE_OPTIONAL_H_ | 12 #define WEBRTC_BASE_OPTIONAL_H_ |
13 | 13 |
14 #include <algorithm> | 14 #include <algorithm> |
| 15 #include <memory> |
15 #include <utility> | 16 #include <utility> |
16 | 17 |
17 #include "webrtc/base/checks.h" | 18 #include "webrtc/base/checks.h" |
18 | 19 |
19 namespace rtc { | 20 namespace rtc { |
20 | 21 |
21 // Simple std::experimental::optional-wannabe. It either contains a T or not. | 22 // Simple std::experimental::optional-wannabe. It either contains a T or not. |
22 // In order to keep the implementation simple and portable, this implementation | 23 // In order to keep the implementation simple and portable, this implementation |
23 // actually contains a (default-constructed) T even when it supposedly doesn't | 24 // actually contains a (default-constructed) T even when it supposedly doesn't |
24 // contain a value; use e.g. rtc::scoped_ptr<T> instead if that's too | 25 // contain a value; use e.g. std::unique_ptr<T> instead if that's too |
25 // expensive. | 26 // expensive. |
26 // | 27 // |
27 // A moved-from Optional<T> may only be destroyed, and assigned to if T allows | 28 // A moved-from Optional<T> may only be destroyed, and assigned to if T allows |
28 // being assigned to after having been moved from. Specifically, you may not | 29 // being assigned to after having been moved from. Specifically, you may not |
29 // assume that it just doesn't contain a value anymore. | 30 // assume that it just doesn't contain a value anymore. |
30 // | 31 // |
31 // Examples of good places to use Optional: | 32 // Examples of good places to use Optional: |
32 // | 33 // |
33 // - As a class or struct member, when the member doesn't always have a value: | 34 // - As a class or struct member, when the member doesn't always have a value: |
34 // struct Prisoner { | 35 // struct Prisoner { |
(...skipping 88 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
123 private: | 124 private: |
124 // Invariant: Unless *this has been moved from, value_ is default-initialized | 125 // Invariant: Unless *this has been moved from, value_ is default-initialized |
125 // (or copied or moved from a default-initialized T) if !has_value_. | 126 // (or copied or moved from a default-initialized T) if !has_value_. |
126 T value_; | 127 T value_; |
127 bool has_value_; | 128 bool has_value_; |
128 }; | 129 }; |
129 | 130 |
130 } // namespace rtc | 131 } // namespace rtc |
131 | 132 |
132 #endif // WEBRTC_BASE_OPTIONAL_H_ | 133 #endif // WEBRTC_BASE_OPTIONAL_H_ |
OLD | NEW |