grpc/include/grpcpp/support/time.h

/*
 *
 * Copyright 2015 gRPC authors.
 *
 * 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.
 *
 */

#ifndef GRPCPP_SUPPORT_TIME_H
#define GRPCPP_SUPPORT_TIME_H

#include <chrono>

#include <grpc/impl/codegen/grpc_types.h>
#include <grpcpp/support/config.h>

namespace grpc {

/** If you are trying to use CompletionQueue::AsyncNext with a time class that
    isn't either gpr_timespec or std::chrono::system_clock::time_point, you
    will most likely be looking at this comment as your compiler will have
    fired an error below. In order to fix this issue, you have two potential
    solutions:

      1. Use gpr_timespec or std::chrono::system_clock::time_point instead
      2. Specialize the TimePoint class with whichever time class that you
         want to use here. See below for two examples of how to do this.
 */
template <typename T>
class TimePoint {
 public:
  // If you see the error with methods below, you may need either
  // i) using the existing types having a conversion class such as
  // gpr_timespec and std::chrono::system_clock::time_point or
  // ii) writing a new TimePoint<YourType> to address your case.
  TimePoint(const T& /*time*/) = delete;
  gpr_timespec raw_time() = delete;
};

template <>
class TimePoint<gpr_timespec> {
 public:
  /* NOLINTNEXTLINE(google-explicit-constructor) */
  TimePoint(const gpr_timespec& time) : time_(time) {}
  gpr_timespec raw_time() { return time_; }

 private:
  gpr_timespec time_;
};

}  // namespace grpc

namespace grpc {

// from and to should be absolute time.
void Timepoint2Timespec(const std::chrono::system_clock::time_point& from,
                        gpr_timespec* to);
void TimepointHR2Timespec(
    const std::chrono::high_resolution_clock::time_point& from,
    gpr_timespec* to);

std::chrono::system_clock::time_point Timespec2Timepoint(gpr_timespec t);

template <>
class TimePoint<std::chrono::system_clock::time_point> {
 public:
  /* NOLINTNEXTLINE(google-explicit-constructor) */
  TimePoint(const std::chrono::system_clock::time_point& time) {
    Timepoint2Timespec(time, &time_);
  }
  gpr_timespec raw_time() const { return time_; }

 private:
  gpr_timespec time_;
};

}  // namespace grpc

#endif  // GRPCPP_SUPPORT_TIME_H