grpc/include/grpc++/time.h

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#ifndef GRPC_INTERNAL_CPP_UTIL_TIME_H
#define GRPC_INTERNAL_CPP_UTIL_TIME_H

#include <grpc++/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 that comment as your compiler will have
   fired the static_assert below. In order to fix that 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 that.
 */

template <typename T>
class TimePoint {
 public:
  TimePoint(const T& time) {
    static_assert(false, "You need a specialization of TimePoint");
  }
  gpr_timespec raw_time() {
    static_assert(false, "You need a specialization of TimePoint");
  }
};

template<>
class TimePoint<gpr_timespec> {
 public:
  TimePoint(const gpr_timespec& time) : time_(time) { }
  gpr_timespec raw_time() { return time_; }
 private:
  gpr_timespec time_;
};

}  // namespace grpc

#ifndef GRPC_CXX0X_NO_CHRONO

#include <chrono>

#include <grpc/support/time.h>

namespace grpc {

// from and to should be absolute time.
void Timepoint2Timespec(const std::chrono::system_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:
  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  // !GRPC_CXX0X_NO_CHRONO

#endif  // GRPC_INTERNAL_CPP_UTIL_TIME_H