Files
scylladb/noexcept_traits.hh
Avi Kivity fcb8d040e8 treewide: use Software Package Data Exchange (SPDX) license identifiers
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.

Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.

The changes we applied mechanically with a script, except to
licenses/README.md.

Closes #9937
2022-01-18 12:15:18 +01:00

70 lines
1.4 KiB
C++

/*
* Copyright 2015-present ScyllaDB
*/
/*
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#include <type_traits>
#include <memory>
#include <seastar/core/future.hh>
#include "seastarx.hh"
#pragma once
//
// Utility for adapting types which are not nothrow move constructible into such
// by wrapping them if necessary.
//
// Example usage:
//
// T val{};
// using traits = noexcept_movable<T>;
// auto f = make_ready_future<typename traits::type>(traits::wrap(std::move(val)));
// T val2 = traits::unwrap(f.get0());
//
template<typename T>
struct noexcept_movable;
template<typename T>
requires std::is_nothrow_move_constructible_v<T>
struct noexcept_movable<T> {
using type = T;
static type wrap(T&& v) {
return std::move(v);
}
static future<T> wrap(future<T>&& v) {
return std::move(v);
}
static T unwrap(type&& v) {
return std::move(v);
}
static future<T> unwrap(future<type>&& v) {
return std::move(v);
}
};
template<typename T>
requires (!std::is_nothrow_move_constructible_v<T>)
struct noexcept_movable<T> {
using type = std::unique_ptr<T>;
static type wrap(T&& v) {
return std::make_unique<T>(std::move(v));
}
static T unwrap(type&& v) {
return std::move(*v);
}
};
template<typename T>
using noexcept_movable_t = typename noexcept_movable<T>::type;