| // Copyright 2019 Google LLC |
| // |
| // 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 |
| // |
| // https://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. |
| |
| #ifndef EMBOSS_PUBLIC_EMBOSS_CONSTANT_VIEW_H_ |
| #define EMBOSS_PUBLIC_EMBOSS_CONSTANT_VIEW_H_ |
| |
| #include "public/emboss_maybe.h" |
| |
| namespace emboss { |
| namespace support { |
| |
| // MaybeConstantView is a "view" type that "reads" a value passed into its |
| // constructor. |
| // |
| // This is used internally by generated structure view classes to provide views |
| // of parameters; in this way, parameters can be treated like fields in the |
| // generated code. |
| template <typename ValueT> |
| class MaybeConstantView { |
| public: |
| MaybeConstantView() : value_() {} |
| constexpr explicit MaybeConstantView(ValueT value) : value_(value) {} |
| MaybeConstantView(const MaybeConstantView &) = default; |
| MaybeConstantView(MaybeConstantView &&) = default; |
| MaybeConstantView &operator=(const MaybeConstantView &) = default; |
| MaybeConstantView &operator=(MaybeConstantView &&) = default; |
| ~MaybeConstantView() = default; |
| |
| constexpr ValueT Read() const { return value_.Value(); } |
| constexpr ValueT UncheckedRead() const { return value_.ValueOrDefault(); } |
| constexpr bool Ok() { return value_.Known(); } |
| |
| private: |
| ::emboss::support::Maybe<ValueT> value_; |
| }; |
| |
| } // namespace support |
| } // namespace emboss |
| |
| #endif // EMBOSS_PUBLIC_EMBOSS_CONSTANT_VIEW_H_ |