blob: 3fd3e997a1780df8b17cb99a6fb5b5766115c133 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <string>
#include <variant>
#include <android-base/logging.h>
namespace android {
namespace jsonpb {
template <typename T>
struct ErrorOr {
template <class... Args>
explicit ErrorOr(Args&&... args) : data_(kIndex1, std::forward<Args>(args)...) {}
T& operator*() {
CHECK(ok());
return *std::get_if<1u>(&data_);
}
const T& operator*() const {
CHECK(ok());
return *std::get_if<1u>(&data_);
}
T* operator->() {
CHECK(ok());
return std::get_if<1u>(&data_);
}
const T* operator->() const {
CHECK(ok());
return std::get_if<1u>(&data_);
}
const std::string& error() const {
CHECK(!ok());
return *std::get_if<0u>(&data_);
}
bool ok() const { return data_.index() != 0; }
static ErrorOr<T> MakeError(const std::string& message) {
return ErrorOr<T>(message, Tag::kDummy);
}
private:
enum class Tag { kDummy };
static constexpr std::in_place_index_t<0> kIndex0{};
static constexpr std::in_place_index_t<1> kIndex1{};
ErrorOr(const std::string& msg, Tag) : data_(kIndex0, msg) {}
std::variant<std::string, T> data_;
};
template <typename T>
inline ErrorOr<T> MakeError(const std::string& message) {
return ErrorOr<T>::MakeError(message);
}
} // namespace jsonpb
} // namespace android
|
