exception.hh

/*
 * This file is open source software, licensed to you under the terms
 * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
 * distributed with this work for additional information regarding copyright
 * ownership.  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.
 */
/*
 * Copyright (C) 2021-present ScyllaDB
 */
 
#pragma once
 
#include <seastar/core/future.hh>
#include <coroutine>
#include <exception>
 
namespace seastar {
 
namespace internal {
 
struct exception_awaiter {
    std::exception_ptr eptr;
 
    explicit exception_awaiter(std::exception_ptr&& eptr) noexcept : eptr(std::move(eptr)) {}
 
    exception_awaiter(const exception_awaiter&) = delete;
    exception_awaiter(exception_awaiter&&) = delete;
 
    bool await_ready() const noexcept {
        return false;
    }
 
    template<typename U>
    void await_suspend(std::coroutine_handle<U> hndl) noexcept {
        hndl.promise().set_exception(std::move(eptr));
        hndl.destroy();
    }
 
    void await_resume() noexcept {}
};
 
} // internal
 
namespace coroutine {
 
struct exception {
    std::exception_ptr eptr;
    explicit exception(std::exception_ptr eptr) noexcept : eptr(std::move(eptr)) {}
};
 
[[deprecated("Use co_await coroutine::return_exception or co_return coroutine::exception instead")]]
[[nodiscard]]
inline exception make_exception(std::exception_ptr ex) noexcept {
    return exception(std::move(ex));
}
 
template<typename T>
[[deprecated("Use co_await coroutine::return_exception or co_return coroutine::exception instead")]]
[[nodiscard]]
exception make_exception(T&& t) noexcept {
    log_exception_trace();
    return exception(std::make_exception_ptr(std::forward<T>(t)));
}
 
[[nodiscard]]
inline exception return_exception_ptr(std::exception_ptr ex) noexcept {
    return exception(std::move(ex));
}
 
[[deprecated("Use co_await coroutine::return_exception_ptr instead")]]
[[nodiscard]]
inline exception return_exception(std::exception_ptr ex) noexcept {
    return exception(std::move(ex));
}
 
template<typename T>
[[nodiscard]]
exception return_exception(T&& t) noexcept {
    log_exception_trace();
    return exception(std::make_exception_ptr(std::forward<T>(t)));
}
 
} // coroutine
 
inline auto operator co_await(coroutine::exception ex) noexcept {
    return internal::exception_awaiter(std::move(ex.eptr));
}
 
} // seastar