condition_node.h

/* Copyright (C) 2015-2018 Michele Colledanchise -  All Rights Reserved
 * Copyright (C) 2018-2025 Davide Faconti, Eurecat -  All Rights Reserved
*
*   Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
*   to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
*   and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
*   The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
*
*   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
*   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
*   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
 
#ifndef CONDITIONNODE_H
#define CONDITIONNODE_H
 
#include "leaf_node.h"
 
namespace BT
{
/**
 * @brief The ConditionNode is a leaf node used to check a condition.
 *
 * Unlike ActionNodes, a ConditionNode should NOT alter the system or have side-effects.
 * and should NOT return RUNNING. It should return SUCCESS or FAILURE
 * synchronously to indicate whether a condition is met.
 *
 * Conditions are typically used to check the state of the world or
 * the system before performing an action (e.g., "IsDoorOpen", "IsBatteryLow").
 */
class ConditionNode : public LeafNode
{
public:
  ConditionNode(const std::string& name, const NodeConfig& config);
 
  ~ConditionNode() override = default;
 
  ConditionNode(const ConditionNode&) = delete;
  ConditionNode& operator=(const ConditionNode&) = delete;
  ConditionNode(ConditionNode&&) = delete;
  ConditionNode& operator=(ConditionNode&&) = delete;
 
  //Do nothing
  virtual void halt() override final
  {
    resetStatus();
  }
 
  virtual NodeType type() const override final
  {
    return NodeType::CONDITION;
  }
};
 
/**
 * @brief The SimpleConditionNode provides an easy to use ConditionNode.
 * The user should simply provide a callback with this signature
 *
 *    BT::NodeStatus functionName(void)
 *
 * This avoids the hassle of inheriting from a ActionNode.
 *
 * Using lambdas or std::bind it is easy to pass a pointer to a method.
 */
class SimpleConditionNode : public ConditionNode
{
public:
  using TickFunctor = std::function<NodeStatus(TreeNode&)>;
 
  // You must provide the function to call when tick() is invoked
  SimpleConditionNode(const std::string& name, TickFunctor tick_functor,
                      const NodeConfig& config);
 
  ~SimpleConditionNode() override = default;
 
  SimpleConditionNode(const SimpleConditionNode&) = delete;
  SimpleConditionNode& operator=(const SimpleConditionNode&) = delete;
  SimpleConditionNode(SimpleConditionNode&&) = delete;
  SimpleConditionNode& operator=(SimpleConditionNode&&) = delete;
 
protected:
  virtual NodeStatus tick() override;
 
  TickFunctor tick_functor_;
};
}  // namespace BT
 
#endif