system_interface.hpp

// Copyright 2020 - 2021 ros2_control Development Team
//
// 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 HARDWARE_INTERFACE__SYSTEM_INTERFACE_HPP_
#define HARDWARE_INTERFACE__SYSTEM_INTERFACE_HPP_
 
#include <limits>
#include <memory>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
 
#include "hardware_interface/component_parser.hpp"
#include "hardware_interface/handle.hpp"
#include "hardware_interface/hardware_info.hpp"
#include "hardware_interface/types/hardware_interface_return_values.hpp"
#include "hardware_interface/types/hardware_interface_type_values.hpp"
#include "hardware_interface/types/lifecycle_state_names.hpp"
#include "lifecycle_msgs/msg/state.hpp"
#include "rclcpp/duration.hpp"
#include "rclcpp/logger.hpp"
#include "rclcpp/logging.hpp"
#include "rclcpp/node_interfaces/node_clock_interface.hpp"
#include "rclcpp/time.hpp"
#include "rclcpp_lifecycle/node_interfaces/lifecycle_node_interface.hpp"
#include "rclcpp_lifecycle/state.hpp"
#include "realtime_tools/async_function_handler.hpp"
 
namespace hardware_interface
{
 
using CallbackReturn = rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn;
 
class SystemInterface : public rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface
{
public:
  SystemInterface()
  : lifecycle_state_(rclcpp_lifecycle::State(
      lifecycle_msgs::msg::State::PRIMARY_STATE_UNKNOWN, lifecycle_state_names::UNKNOWN)),
    system_logger_(rclcpp::get_logger("system_interface"))
  {
  }
 
 
  SystemInterface(const SystemInterface & other) = delete;
 
  SystemInterface(SystemInterface && other) = default;
 
  virtual ~SystemInterface() = default;
 
 
  CallbackReturn init(
    const HardwareInfo & hardware_info, rclcpp::Logger logger,
    rclcpp::node_interfaces::NodeClockInterface::SharedPtr clock_interface)
  {
    clock_interface_ = clock_interface;
    system_logger_ = logger.get_child("hardware_component.system." + hardware_info.name);
    info_ = hardware_info;
    if (info_.is_async)
    {
      RCLCPP_INFO_STREAM(
        get_logger(), "Starting async handler with scheduler priority: " << info_.thread_priority);
      async_handler_ = std::make_unique<realtime_tools::AsyncFunctionHandler<return_type>>();
      async_handler_->init(
        [this](const rclcpp::Time & time, const rclcpp::Duration & period)
        {
          if (next_trigger_ == TriggerType::READ)
          {
            const auto ret = read(time, period);
            next_trigger_ = TriggerType::WRITE;
            return ret;
          }
          else
          {
            const auto ret = write(time, period);
            next_trigger_ = TriggerType::READ;
            return ret;
          }
        },
        info_.thread_priority);
      async_handler_->start_thread();
    }
    return on_init(hardware_info);
  };
 
 
  virtual CallbackReturn on_init(const HardwareInfo & hardware_info)
  {
    info_ = hardware_info;
    parse_state_interface_descriptions(info_.joints, joint_state_interfaces_);
    parse_state_interface_descriptions(info_.sensors, sensor_state_interfaces_);
    parse_state_interface_descriptions(info_.gpios, gpio_state_interfaces_);
    parse_command_interface_descriptions(info_.joints, joint_command_interfaces_);
    parse_command_interface_descriptions(info_.gpios, gpio_command_interfaces_);
    return CallbackReturn::SUCCESS;
  };
 
 
  [[deprecated(
    "Replaced by vector<StateInterface::ConstSharedPtr> on_export_state_interfaces() method. "
    "Exporting is handled "
    "by the Framework.")]] virtual std::vector<StateInterface>
  export_state_interfaces()
  {
    // return empty vector by default. For backward compatibility we try calling
    // export_state_interfaces() and only when empty vector is returned call
    // on_export_state_interfaces()
    return {};
  }
 
  virtual std::vector<hardware_interface::InterfaceDescription>
  export_unlisted_state_interface_descriptions()
  {
    // return empty vector by default.
    return {};
  }
 
  virtual std::vector<StateInterface::ConstSharedPtr> on_export_state_interfaces()
  {
    // import the unlisted interfaces
    std::vector<hardware_interface::InterfaceDescription> unlisted_interface_descriptions =
      export_unlisted_state_interface_descriptions();
 
    std::vector<StateInterface::ConstSharedPtr> state_interfaces;
    state_interfaces.reserve(
      unlisted_interface_descriptions.size() + joint_state_interfaces_.size() +
      sensor_state_interfaces_.size() + gpio_state_interfaces_.size());
 
    // add InterfaceDescriptions and create the StateInterfaces from the descriptions and add to
    // maps.
    for (const auto & description : unlisted_interface_descriptions)
    {
      auto name = description.get_name();
      unlisted_state_interfaces_.insert(std::make_pair(name, description));
      auto state_interface = std::make_shared<StateInterface>(description);
      system_states_.insert(std::make_pair(name, state_interface));
      unlisted_states_.push_back(state_interface);
      state_interfaces.push_back(std::const_pointer_cast<const StateInterface>(state_interface));
    }
 
    for (const auto & [name, descr] : joint_state_interfaces_)
    {
      auto state_interface = std::make_shared<StateInterface>(descr);
      system_states_.insert(std::make_pair(name, state_interface));
      joint_states_.push_back(state_interface);
      state_interfaces.push_back(std::const_pointer_cast<const StateInterface>(state_interface));
    }
    for (const auto & [name, descr] : sensor_state_interfaces_)
    {
      auto state_interface = std::make_shared<StateInterface>(descr);
      system_states_.insert(std::make_pair(name, state_interface));
      sensor_states_.push_back(state_interface);
      state_interfaces.push_back(std::const_pointer_cast<const StateInterface>(state_interface));
    }
    for (const auto & [name, descr] : gpio_state_interfaces_)
    {
      auto state_interface = std::make_shared<StateInterface>(descr);
      system_states_.insert(std::make_pair(name, state_interface));
      gpio_states_.push_back(state_interface);
      state_interfaces.push_back(std::const_pointer_cast<const StateInterface>(state_interface));
    }
    return state_interfaces;
  }
 
 
  [[deprecated(
    "Replaced by vector<CommandInterface::SharedPtr> on_export_command_interfaces() method. "
    "Exporting is "
    "handled "
    "by the Framework.")]] virtual std::vector<CommandInterface>
  export_command_interfaces()
  {
    // return empty vector by default. For backward compatibility we try calling
    // export_command_interfaces() and only when empty vector is returned call
    // on_export_command_interfaces()
    return {};
  }
 
  virtual std::vector<hardware_interface::InterfaceDescription>
  export_unlisted_command_interface_descriptions()
  {
    // return empty vector by default.
    return {};
  }
 
  virtual std::vector<CommandInterface::SharedPtr> on_export_command_interfaces()
  {
    // import the unlisted interfaces
    std::vector<hardware_interface::InterfaceDescription> unlisted_interface_descriptions =
      export_unlisted_command_interface_descriptions();
 
    std::vector<CommandInterface::SharedPtr> command_interfaces;
    command_interfaces.reserve(
      unlisted_interface_descriptions.size() + joint_command_interfaces_.size() +
      gpio_command_interfaces_.size());
 
    // add InterfaceDescriptions and create the CommandInterfaces from the descriptions and add to
    // maps.
    for (const auto & description : unlisted_interface_descriptions)
    {
      auto name = description.get_name();
      unlisted_command_interfaces_.insert(std::make_pair(name, description));
      auto command_interface = std::make_shared<CommandInterface>(description);
      system_commands_.insert(std::make_pair(name, command_interface));
      unlisted_commands_.push_back(command_interface);
      command_interfaces.push_back(command_interface);
    }
 
    for (const auto & [name, descr] : joint_command_interfaces_)
    {
      auto command_interface = std::make_shared<CommandInterface>(descr);
      system_commands_.insert(std::make_pair(name, command_interface));
      joint_commands_.push_back(command_interface);
      command_interfaces.push_back(command_interface);
    }
 
    for (const auto & [name, descr] : gpio_command_interfaces_)
    {
      auto command_interface = std::make_shared<CommandInterface>(descr);
      system_commands_.insert(std::make_pair(name, command_interface));
      gpio_commands_.push_back(command_interface);
      command_interfaces.push_back(command_interface);
    }
    return command_interfaces;
  }
 
 
  virtual return_type prepare_command_mode_switch(
    const std::vector<std::string> & /*start_interfaces*/,
    const std::vector<std::string> & /*stop_interfaces*/)
  {
    return return_type::OK;
  }
 
  // Perform switching to the new command interface.
  virtual return_type perform_command_mode_switch(
    const std::vector<std::string> & /*start_interfaces*/,
    const std::vector<std::string> & /*stop_interfaces*/)
  {
    return return_type::OK;
  }
 
 
  return_type trigger_read(const rclcpp::Time & time, const rclcpp::Duration & period)
  {
    return_type result = return_type::ERROR;
    if (info_.is_async)
    {
      bool trigger_status = true;
      if (next_trigger_ == TriggerType::WRITE)
      {
        RCLCPP_WARN(
          get_logger(),
          "Trigger read called while write async handler call is still pending for hardware "
          "interface : '%s'. Skipping read cycle and will wait for a write cycle!",
          info_.name.c_str());
        return return_type::OK;
      }
      std::tie(trigger_status, result) = async_handler_->trigger_async_callback(time, period);
      if (!trigger_status)
      {
        RCLCPP_WARN(
          get_logger(),
          "Trigger read called while write async trigger is still in progress for hardware "
          "interface : '%s'. Failed to trigger read cycle!",
          info_.name.c_str());
        return return_type::OK;
      }
    }
    else
    {
      result = read(time, period);
    }
    return result;
  }
 
 
  virtual return_type read(const rclcpp::Time & time, const rclcpp::Duration & period) = 0;
 
 
  return_type trigger_write(const rclcpp::Time & time, const rclcpp::Duration & period)
  {
    return_type result = return_type::ERROR;
    if (info_.is_async)
    {
      bool trigger_status = true;
      if (next_trigger_ == TriggerType::READ)
      {
        RCLCPP_WARN(
          get_logger(),
          "Trigger write called while read async handler call is still pending for hardware "
          "interface : '%s'. Skipping write cycle and will wait for a read cycle!",
          info_.name.c_str());
        return return_type::OK;
      }
      std::tie(trigger_status, result) = async_handler_->trigger_async_callback(time, period);
      if (!trigger_status)
      {
        RCLCPP_WARN(
          get_logger(),
          "Trigger write called while read async trigger is still in progress for hardware "
          "interface : '%s'. Failed to trigger write cycle!",
          info_.name.c_str());
        return return_type::OK;
      }
    }
    else
    {
      result = write(time, period);
    }
    return result;
  }
 
 
  virtual return_type write(const rclcpp::Time & time, const rclcpp::Duration & period) = 0;
 
 
  virtual std::string get_name() const { return info_.name; }
 
 
  virtual std::string get_group_name() const { return info_.group; }
 
 
  const rclcpp_lifecycle::State & get_lifecycle_state() const { return lifecycle_state_; }
 
 
  void set_lifecycle_state(const rclcpp_lifecycle::State & new_state)
  {
    lifecycle_state_ = new_state;
  }
 
  void set_state(const std::string & interface_name, const double & value)
  {
    system_states_.at(interface_name)->set_value(value);
  }
 
  double get_state(const std::string & interface_name) const
  {
    return system_states_.at(interface_name)->get_value();
  }
 
  void set_command(const std::string & interface_name, const double & value)
  {
    system_commands_.at(interface_name)->set_value(value);
  }
 
  double get_command(const std::string & interface_name) const
  {
    return system_commands_.at(interface_name)->get_value();
  }
 
 
  rclcpp::Logger get_logger() const { return system_logger_; }
 
 
  rclcpp::Clock::SharedPtr get_clock() const { return clock_interface_->get_clock(); }
 
 
  const HardwareInfo & get_hardware_info() const { return info_; }
 
protected:
  HardwareInfo info_;
  // interface names to InterfaceDescription
  std::unordered_map<std::string, InterfaceDescription> joint_state_interfaces_;
  std::unordered_map<std::string, InterfaceDescription> joint_command_interfaces_;
 
  std::unordered_map<std::string, InterfaceDescription> sensor_state_interfaces_;
 
  std::unordered_map<std::string, InterfaceDescription> gpio_state_interfaces_;
  std::unordered_map<std::string, InterfaceDescription> gpio_command_interfaces_;
 
  std::unordered_map<std::string, InterfaceDescription> unlisted_state_interfaces_;
  std::unordered_map<std::string, InterfaceDescription> unlisted_command_interfaces_;
 
  rclcpp_lifecycle::State lifecycle_state_;
  std::unique_ptr<realtime_tools::AsyncFunctionHandler<return_type>> async_handler_;
 
  // Exported Command- and StateInterfaces in order they are listed in the hardware description.
  std::vector<StateInterface::SharedPtr> joint_states_;
  std::vector<CommandInterface::SharedPtr> joint_commands_;
 
  std::vector<StateInterface::SharedPtr> sensor_states_;
 
  std::vector<StateInterface::SharedPtr> gpio_states_;
  std::vector<CommandInterface::SharedPtr> gpio_commands_;
 
  std::vector<StateInterface::SharedPtr> unlisted_states_;
  std::vector<CommandInterface::SharedPtr> unlisted_commands_;
 
private:
  rclcpp::node_interfaces::NodeClockInterface::SharedPtr clock_interface_;
  rclcpp::Logger system_logger_;
  // interface names to Handle accessed through getters/setters
  std::unordered_map<std::string, StateInterface::SharedPtr> system_states_;
  std::unordered_map<std::string, CommandInterface::SharedPtr> system_commands_;
  enum class TriggerType
  {
    READ,
    WRITE
  };
  std::atomic<TriggerType> next_trigger_ = TriggerType::READ;
};
 
}  // namespace hardware_interface
#endif  // HARDWARE_INTERFACE__SYSTEM_INTERFACE_HPP_