backend_list.h

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/*
 * Copyright 2023 MusicScience37 (Kenta Kabashima)
 *
 * 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 <memory>
#include <string>
#include <string_view>
#include <unordered_map>
#include <utility>
 
#include <fmt/format.h>
 
#include "msgpack_rpc/common/msgpack_rpc_exception.h"
#include "msgpack_rpc/common/status_code.h"
#include "msgpack_rpc/transport/i_backend.h"
 
namespace msgpack_rpc::transport {

class BackendList {
public:
    BackendList() = default;

    void append(std::shared_ptr<transport::IBackend> backend) {
        const auto scheme = backend->scheme();
        const auto result = backends_.try_emplace(scheme, std::move(backend));
        if (!result.second) {
            throw MsgpackRPCException(StatusCode::INVALID_ARGUMENT,
                fmt::format("Duplicate scheme : \"{}\".", scheme));
        }
    }

    [[nodiscard]] std::shared_ptr<transport::IBackend> find(
        std::string_view scheme) const {
        const auto backend_iter = backends_.find(scheme);
        if (backend_iter == backends_.end()) {
            throw MsgpackRPCException(StatusCode::INVALID_ARGUMENT,
                fmt::format("Invalid scheme: {}.", scheme));
        }
        return backend_iter->second;
    }
 
private:
    std::unordered_map<std::string_view, std::shared_ptr<transport::IBackend>>
        backends_{};
};
 
}  // namespace msgpack_rpc::transport