executor_base.hpp

// Copyright 2024 Robin Müller
//
// 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
//
//      https://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.
 
#pragma once
 
#include <chrono>
#include <functional>
#include <future>
#include <memory>
 
#include "auto_apms_behavior_tree/exceptions.hpp"
#include "auto_apms_behavior_tree/executor/state_observer.hpp"
#include "auto_apms_behavior_tree_core/definitions.hpp"
#include "behaviortree_cpp/loggers/groot2_publisher.h"
#include "rclcpp/node.hpp"
 
namespace auto_apms_behavior_tree
{

class TreeExecutorBase : public std::enable_shared_from_this<TreeExecutorBase>
{
public:
  enum class ExecutionState : uint8_t
  {
    IDLE,      
    STARTING,  
    RUNNING,   
    PAUSED,    
    HALTED     
  };

  enum class ControlCommand : uint8_t
  {
    RUN,       
    PAUSE,     
    HALT,      
    TERMINATE  
  };

  enum class TreeExitBehavior : uint8_t
  {
    TERMINATE,  
    RESTART     
  };

  enum class ExecutionResult : uint8_t
  {
    TREE_SUCCEEDED,          
    TREE_FAILED,             
    TERMINATED_PREMATURELY,  
    ERROR                    
  };
 
private:
  using TerminationCallback = std::function<void(ExecutionResult, const std::string &)>;
 
public:
  TreeExecutorBase(
    rclcpp::Node::SharedPtr node_ptr, rclcpp::CallbackGroup::SharedPtr tree_node_callback_group_ptr = nullptr);
 
  virtual ~TreeExecutorBase() = default;

  std::shared_future<ExecutionResult> startExecution(
    TreeConstructor make_tree, double tick_rate_sec = 0.1, int groot2_port = -1);

  template <typename TimeRepT = int64_t, typename TimeT = std::milli>
  std::shared_future<ExecutionResult> startExecution(
    TreeConstructor make_tree, const std::chrono::duration<TimeRepT, TimeT> & tick_rate, int groot2_port = -1);
 
private:
  void tick_callback_(TerminationCallback termination_callback);
 
  /* Virtual methods */

  virtual bool onInitialTick();

  virtual bool onTick();

  virtual bool afterTick();

  virtual TreeExitBehavior onTreeExit(bool success);

  virtual void onTermination(const ExecutionResult & result);
 
public:
  void setControlCommand(ControlCommand cmd);

  bool isBusy();

  ExecutionState getExecutionState();

  std::string getTreeName();

  TreeBlackboardSharedPtr getGlobalBlackboardPtr();

  void clearGlobalBlackboard();

  TreeStateObserver & getStateObserver();

  rclcpp::Node::SharedPtr getNodePtr();

  rclcpp::node_interfaces::NodeBaseInterface::SharedPtr get_node_base_interface();

  rclcpp::CallbackGroup::SharedPtr getTreeNodeWaitablesCallbackGroupPtr();

  rclcpp::executors::SingleThreadedExecutor::SharedPtr getTreeNodeWaitablesExecutorPtr();
 
protected:
  rclcpp::Node::SharedPtr node_ptr_;
  const rclcpp::Logger logger_;
 
private:
  rclcpp::CallbackGroup::SharedPtr tree_node_waitables_callback_group_ptr_;
  rclcpp::executors::SingleThreadedExecutor::SharedPtr tree_node_waitables_executor_ptr_;
  TreeBlackboardSharedPtr global_blackboard_ptr_;
  std::unique_ptr<Tree> tree_ptr_;
  std::unique_ptr<BT::Groot2Publisher> groot2_publisher_ptr_;
  std::unique_ptr<TreeStateObserver> state_observer_ptr_;
  rclcpp::TimerBase::SharedPtr execution_timer_ptr_;
  ExecutionState prev_execution_state_;
  ControlCommand control_command_;
  bool execution_stopped_;
  std::string termination_reason_;
};
 
std::string toStr(TreeExecutorBase::ExecutionState state);
 
std::string toStr(TreeExecutorBase::ControlCommand cmd);
 
std::string toStr(TreeExecutorBase::TreeExitBehavior behavior);
 
std::string toStr(TreeExecutorBase::ExecutionResult result);
 
// #####################################################################################################################
// ################################              DEFINITIONS              ##############################################
// #####################################################################################################################
 
template <typename TimeRepT, typename TimeT>
inline std::shared_future<TreeExecutorBase::ExecutionResult> TreeExecutorBase::startExecution(
  TreeConstructor make_tree, const std::chrono::duration<TimeRepT, TimeT> & tick_rate, int groot2_port)
{
  return startExecution(
    make_tree, std::chrono::duration_cast<std::chrono::duration<double>>(tick_rate).count(), groot2_port);
}
 
}  // namespace auto_apms_behavior_tree