timer.hpp

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// Copyright 2014 Open Source Robotics Foundation, Inc.
//
// 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 RCLCPP__TIMER_HPP_
#define RCLCPP__TIMER_HPP_

#include <chrono>
#include <functional>
#include <memory>
#include <sstream>
#include <thread>
#include <type_traits>
#include <utility>

#include "rclcpp/function_traits.hpp"
#include "rclcpp/macros.hpp"
#include "rclcpp/rate.hpp"
#include "rclcpp/utilities.hpp"
#include "rclcpp/visibility_control.hpp"

#include "rcl/error_handling.h"
#include "rcl/timer.h"

#include "rmw/error_handling.h"
#include "rmw/rmw.h"

namespace rclcpp
{

class TimerBase
{
public:
  RCLCPP_SMART_PTR_DEFINITIONS_NOT_COPYABLE(TimerBase)

  RCLCPP_PUBLIC
  explicit TimerBase(std::chrono::nanoseconds period);

  RCLCPP_PUBLIC
  ~TimerBase();

  RCLCPP_PUBLIC
  void
  cancel();

  RCLCPP_PUBLIC
  void
  reset();

  RCLCPP_PUBLIC
  virtual void
  execute_callback() = 0;

  RCLCPP_PUBLIC
  std::shared_ptr<const rcl_timer_t>
  get_timer_handle();


  RCLCPP_PUBLIC
  std::chrono::nanoseconds
  time_until_trigger();


  virtual bool is_steady() = 0;


  RCLCPP_PUBLIC
  bool is_ready();

protected:
  std::shared_ptr<rcl_timer_t> timer_handle_;
};


using VoidCallbackType = std::function<void()>;
using TimerCallbackType = std::function<void(TimerBase &)>;

template<
  typename FunctorT,
  class Clock,
  typename std::enable_if<
    (rclcpp::function_traits::same_arguments<FunctorT, VoidCallbackType>::value ||
    rclcpp::function_traits::same_arguments<FunctorT, TimerCallbackType>::value) &&
    Clock::is_steady
  >::type * = nullptr
>
class GenericTimer : public TimerBase
{
public:
  RCLCPP_SMART_PTR_DEFINITIONS(GenericTimer)

  

  GenericTimer(std::chrono::nanoseconds period, FunctorT && callback)
  : TimerBase(period), callback_(std::forward<FunctorT>(callback))
  {
  }

  virtual ~GenericTimer()
  {
    // Stop the timer from running.
    cancel();
  }

  void
  execute_callback()
  {
    rcl_ret_t ret = rcl_timer_call(timer_handle_.get());
    if (ret == RCL_RET_TIMER_CANCELED) {
      return;
    }
    if (ret != RCL_RET_OK) {
      throw std::runtime_error("Failed to notify timer that callback occurred");
    }
    execute_callback_delegate<>();
  }

  // void specialization
  template<
    typename CallbackT = FunctorT,
    typename std::enable_if<
      rclcpp::function_traits::same_arguments<CallbackT, VoidCallbackType>::value
    >::type * = nullptr
  >
  void
  execute_callback_delegate()
  {
    callback_();
  }

  template<
    typename CallbackT = FunctorT,
    typename std::enable_if<
      rclcpp::function_traits::same_arguments<CallbackT, TimerCallbackType>::value
    >::type * = nullptr
  >
  void
  execute_callback_delegate()
  {
    callback_(*this);
  }

  virtual bool
  is_steady()
  {
    return Clock::is_steady;
  }

protected:
  RCLCPP_DISABLE_COPY(GenericTimer)

  FunctorT callback_;
};

template<typename CallbackType>
using WallTimer = GenericTimer<CallbackType, std::chrono::steady_clock>;

}  // namespace rclcpp

#endif  // RCLCPP__TIMER_HPP_