ApiResponse.h

/*
 * Copyright (C) 2019-2022 HERE Europe B.V.
 *
 * 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.
 *
 * SPDX-License-Identifier: Apache-2.0
 * License-Filename: LICENSE
 */
 
#pragma once
 
#include <future>
#include <memory>
#include <string>
#include <type_traits>
#include <utility>
 
#include "CancellationToken.h"
 
namespace olp {
namespace client {
 
template <typename Payload>
class ResponseExtension {
 public:
  ResponseExtension() = default;
 
  explicit ResponseExtension(Payload payload) : payload_(std::move(payload)) {}
 
  const Payload& GetPayload() const { return payload_; }
 
 protected:
  Payload payload_{};
};
 
template <>
class ResponseExtension<void> {
 public:
  ResponseExtension() = default;
};
 
template <typename Result, typename Error, typename Payload = void>
class ApiResponse : public ResponseExtension<Payload> {
 public:
  using ResultType = Result;
 
  using ErrorType = Error;
 
  using PayloadType = Payload;
 
  ApiResponse() = default;
 
  template <
      typename P = Payload, typename R = Result,
      typename = typename std::enable_if<!std::is_same<P, void>::value>::type,
      typename =
          typename std::enable_if<std::is_copy_constructible<R>::value>::type>
  ApiResponse(const ApiResponse<R, Error, void>& other)  // NOLINT
      : ResponseExtension<P>(),
        result_(other.GetResult()),
        error_(other.GetError()),
        success_(other.IsSuccessful()) {}
 
  template <
      typename P = Payload, typename R = Result,
      typename = typename std::enable_if<!std::is_same<P, void>::value>::type,
      typename =
          typename std::enable_if<std::is_move_constructible<R>::value>::type>
  ApiResponse(ApiResponse<R, Error, void>&& other)  // NOLINT
      : ResponseExtension<P>(),
        result_(other.MoveResult()),
        error_(other.GetError()),
        success_(other.IsSuccessful()) {}
 
  template <typename P = Payload, typename = typename std::enable_if<
                                      !std::is_same<P, void>::value>::type>
  ApiResponse(const ApiResponse<Result, Error, void>& other, P payload)
      : ResponseExtension<P>(std::move(payload)),
        result_(other.GetResult()),
        error_(other.GetError()),
        success_(other.IsSuccessful()) {}
 
  template <
      typename U, typename P = Payload, typename R = Result,
      typename = typename std::enable_if<std::is_same<P, void>::value>::type,
      typename =
          typename std::enable_if<std::is_copy_constructible<R>::value>::type>
  ApiResponse(const ApiResponse<R, Error, U>& other)
      : ResponseExtension<P>(),
        result_(other.GetResult()),
        error_(other.GetError()),
        success_(other.IsSuccessful()) {}
 
  template <
      typename U, typename P = Payload, typename R = Result,
      typename = typename std::enable_if<std::is_same<P, void>::value>::type,
      typename =
          typename std::enable_if<std::is_move_constructible<R>::value>::type>
  ApiResponse(ApiResponse<R, Error, U>&& other)
      : ResponseExtension<P>(),
        result_(other.MoveResult()),
        error_(other.GetError()),
        success_(other.IsSuccessful()) {}
 
  ApiResponse(ResultType result)  // NOLINT
      : ResponseExtension<Payload>(),
        result_(std::move(result)),
        success_(true) {}
 
  template <typename P = Payload, typename = typename std::enable_if<
                                      !std::is_same<P, void>::value>::type>
  ApiResponse(ResultType result, P payload)
      : ResponseExtension<Payload>(std::move(payload)),
        result_(std::move(result)),
        success_(true) {}
 
  ApiResponse(const ErrorType& error)  // NOLINT
      : error_(error), success_(false) {}
 
  template <typename P = Payload, typename = typename std::enable_if<
                                      !std::is_same<P, void>::value>::type>
  ApiResponse(const ErrorType& error, P payload)
      : ResponseExtension<Payload>(std::move(payload)),
        error_(error),
        success_(false) {}
 
  inline bool IsSuccessful() const { return success_; }
 
  inline const ResultType& GetResult() const { return result_; }
 
  inline ResultType&& MoveResult() { return std::move(result_); }
 
  inline const ErrorType& GetError() const { return error_; }
 
  inline explicit operator bool() const { return IsSuccessful(); }
 
 private:
  ResultType result_{};
  ErrorType error_{};
  bool success_{false};
};
 
template <typename T>
class CancellableFuture {
 public:
  using PromisePtr = std::shared_ptr<std::promise<T>>;
 
  CancellableFuture(const CancellationToken& cancel_token, PromisePtr promise)
      : cancel_token_(cancel_token), promise_(std::move(promise)) {}
 
  inline const CancellationToken& GetCancellationToken() const {
    return cancel_token_;
  }
 
  inline std::future<T> GetFuture() const { return promise_->get_future(); }
 
 private:
  CancellationToken cancel_token_;
  PromisePtr promise_;
};
 
}  // namespace client
}  // namespace olp