Program Listing for File 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 <atomic>
#include <chrono>
#include <functional>
#include <memory>
#include <sstream>
#include <thread>
#include <type_traits>
#include <utility>

#include "rclcpp/clock.hpp"
#include "rclcpp/context.hpp"
#include "rclcpp/function_traits.hpp"
#include "rclcpp/macros.hpp"
#include "rclcpp/rate.hpp"
#include "rclcpp/utilities.hpp"
#include "rclcpp/visibility_control.hpp"
#include "tracetools/tracetools.h"
#include "tracetools/utils.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(
    Clock::SharedPtr clock,
    std::chrono::nanoseconds period,
    rclcpp::Context::SharedPtr context);

  RCLCPP_PUBLIC
  virtual
  ~TimerBase();


  RCLCPP_PUBLIC
  void
  cancel();


  RCLCPP_PUBLIC
  bool
  is_canceled();


  RCLCPP_PUBLIC
  void
  reset();


  RCLCPP_PUBLIC
  virtual bool
  call() = 0;

  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();


  RCLCPP_PUBLIC
  bool
  exchange_in_use_by_wait_set_state(bool in_use_state);


  RCLCPP_PUBLIC
  void
  set_on_reset_callback(std::function<void(size_t)> callback);

  RCLCPP_PUBLIC
  void
  clear_on_reset_callback();

protected:
  std::recursive_mutex callback_mutex_;
  // Declare callback before timer_handle_, so on destruction
  // the callback is destroyed last. Otherwise, the rcl timer
  // callback would point briefly to a destroyed function.
  // Clearing the callback on timer destructor also makes sure
  // the rcl callback is cleared before on_reset_callback_.
  std::function<void(size_t)> on_reset_callback_{nullptr};

  Clock::SharedPtr clock_;
  std::shared_ptr<rcl_timer_t> timer_handle_;

  std::atomic<bool> in_use_by_wait_set_{false};

  RCLCPP_PUBLIC
  void
  set_on_reset_callback(rcl_event_callback_t callback, const void * user_data);
};


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

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


  explicit GenericTimer(
    Clock::SharedPtr clock, std::chrono::nanoseconds period, FunctorT && callback,
    rclcpp::Context::SharedPtr context
  )
  : TimerBase(clock, period, context), callback_(std::forward<FunctorT>(callback))
  {
    TRACEPOINT(
      rclcpp_timer_callback_added,
      static_cast<const void *>(get_timer_handle().get()),
      reinterpret_cast<const void *>(&callback_));
#ifndef TRACETOOLS_DISABLED
    if (TRACEPOINT_ENABLED(rclcpp_callback_register)) {
      char * symbol = tracetools::get_symbol(callback_);
      DO_TRACEPOINT(
        rclcpp_callback_register,
        reinterpret_cast<const void *>(&callback_),
        symbol);
      std::free(symbol);
    }
#endif
  }

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

  bool
  call() override
  {
    rcl_ret_t ret = rcl_timer_call(timer_handle_.get());
    if (ret == RCL_RET_TIMER_CANCELED) {
      return false;
    }
    if (ret != RCL_RET_OK) {
      throw std::runtime_error("Failed to notify timer that callback occurred");
    }
    return true;
  }

  void
  execute_callback() override
  {
    TRACEPOINT(callback_start, reinterpret_cast<const void *>(&callback_), false);
    execute_callback_delegate<>();
    TRACEPOINT(callback_end, reinterpret_cast<const void *>(&callback_));
  }

  // 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);
  }


  bool
  is_steady() override
  {
    return clock_->get_clock_type() == RCL_STEADY_TIME;
  }

protected:
  RCLCPP_DISABLE_COPY(GenericTimer)

  FunctorT callback_;
};

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


  WallTimer(
    std::chrono::nanoseconds period,
    FunctorT && callback,
    rclcpp::Context::SharedPtr context)
  : GenericTimer<FunctorT>(
      std::make_shared<Clock>(RCL_STEADY_TIME), period, std::move(callback), context)
  {}

protected:
  RCLCPP_DISABLE_COPY(WallTimer)
};

}  // namespace rclcpp

#endif  // RCLCPP__TIMER_HPP_