mirror of
https://github.com/ton-blockchain/ton
synced 2025-03-09 15:40:10 +00:00
108 lines
2.6 KiB
C++
108 lines
2.6 KiB
C++
/*
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This file is part of TON Blockchain Library.
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TON Blockchain Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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TON Blockchain Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with TON Blockchain Library. If not, see <http://www.gnu.org/licenses/>.
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Copyright 2017-2020 Telegram Systems LLP
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*/
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#pragma once
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#include "td/utils/common.h"
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#include "td/utils/Status.h"
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#include <type_traits>
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#include <utility>
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namespace td {
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template <class T, bool = std::is_copy_constructible<T>::value>
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class optional {
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public:
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optional() = default;
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template <class T1,
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std::enable_if_t<!std::is_same<std::decay_t<T1>, optional>::value && std::is_constructible<T, T1>::value,
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int> = 0>
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optional(T1 &&t) : impl_(std::forward<T1>(t)) {
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}
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optional(const optional &other) {
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if (other) {
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impl_ = Result<T>(other.value());
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}
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}
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optional &operator=(const optional &other) {
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if (other) {
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impl_ = Result<T>(other.value());
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} else {
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impl_ = Result<T>();
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}
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return *this;
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}
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optional(optional &&other) = default;
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optional &operator=(optional &&other) = default;
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~optional() = default;
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explicit operator bool() const {
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return impl_.is_ok();
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}
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T &value() {
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DCHECK(*this);
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return impl_.ok_ref();
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}
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const T &value() const {
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DCHECK(*this);
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return impl_.ok_ref();
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}
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T &operator*() {
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return value();
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}
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T unwrap() {
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CHECK(*this);
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auto res = std::move(value());
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impl_ = {};
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return res;
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}
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td::optional<T> copy() const {
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if (*this) {
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return value();
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}
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return {};
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}
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template <class... ArgsT>
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void emplace(ArgsT &&... args) {
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impl_.emplace(std::forward<ArgsT>(args)...);
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}
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private:
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Result<T> impl_;
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};
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template <typename T>
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struct optional<T, false> : optional<T, true> {
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optional() = default;
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using optional<T, true>::optional;
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optional(const optional &other) = delete;
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optional &operator=(const optional &other) = delete;
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optional(optional &&) = default;
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optional &operator=(optional &&) = default;
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~optional() = default;
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};
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} // namespace td
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