clock.hpp

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// Copyright 2017 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__CLOCK_HPP_
#define RCLCPP__CLOCK_HPP_

#include <functional>
#include <memory>
#include <mutex>
#include <vector>

#include "rclcpp/macros.hpp"
#include "rclcpp/time.hpp"
#include "rclcpp/visibility_control.hpp"

#include "rcl/time.h"

namespace rclcpp
{

class TimeSource;


struct TimeJump
{
  typedef enum ClockChange_t
  {
    ROS_TIME_NO_CHANGE,    
    ROS_TIME_ACTIVATED,    
    ROS_TIME_DEACTIVATED,  
    SYSTEM_TIME_NO_CHANGE  
  } ClockChange_t;

  ClockChange_t jump_type_;  
  rcl_duration_t delta_;     
};


class JumpThreshold
{
public:
  uint64_t min_forward_;   
  uint64_t min_backward_;  
  bool on_clock_change_;   

  // Test if the threshold is exceeded by a TimeJump
  RCLCPP_PUBLIC
  bool
  is_exceeded(const TimeJump & jump);
};

class JumpHandler
{
public:
  RCLCPP_SMART_PTR_DEFINITIONS(JumpHandler)
  JumpHandler(
    std::function<void()> pre_callback,
    std::function<void(TimeJump)> post_callback,
    JumpThreshold & threshold);

  std::function<void()> pre_callback;
  std::function<void(const TimeJump &)> post_callback;
  JumpThreshold notice_threshold;
};

class Clock
{
public:
  RCLCPP_SMART_PTR_DEFINITIONS(Clock)

  RCLCPP_PUBLIC
  explicit Clock(rcl_clock_type_t clock_type = RCL_SYSTEM_TIME);

  RCLCPP_PUBLIC
  ~Clock();

  RCLCPP_PUBLIC
  Time
  now();

  RCLCPP_PUBLIC
  bool
  ros_time_is_active();

  RCLCPP_PUBLIC
  rcl_clock_type_t
  get_clock_type();

  // Add a callback to invoke if the jump threshold is exceeded.
  RCLCPP_PUBLIC
  JumpHandler::SharedPtr
  create_jump_callback(
    std::function<void()> pre_callback,
    std::function<void(const TimeJump &)> post_callback,
    JumpThreshold & threshold);

private:
  // A method for TimeSource to get a list of callbacks to invoke while updating
  RCLCPP_PUBLIC
  std::vector<JumpHandler::SharedPtr>
  get_triggered_callback_handlers(const TimeJump & jump);

  // Invoke callbacks that are valid and outside threshold.
  RCLCPP_PUBLIC
  static void invoke_prejump_callbacks(
    const std::vector<JumpHandler::SharedPtr> & callbacks);

  RCLCPP_PUBLIC
  static void invoke_postjump_callbacks(
    const std::vector<JumpHandler::SharedPtr> & callbacks,
    const TimeJump & jump);

  rcl_clock_t rcl_clock_;
  friend TimeSource;  
  rcl_allocator_t allocator_;

  std::mutex callback_list_mutex_;
  std::vector<std::weak_ptr<JumpHandler>> active_jump_handlers_;
};

}  // namespace rclcpp

#endif  // RCLCPP__CLOCK_HPP_