action_node.h

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/* Copyright (C) 2015-2018 Michele Colledanchise -  All Rights Reserved
 * Copyright (C) 2018 Davide Faconti -  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 BEHAVIORTREECORE_ACTIONNODE_H
#define BEHAVIORTREECORE_ACTIONNODE_H

#include <atomic>
#include "leaf_node.h"

namespace BT
{
class ActionNodeBase : public LeafNode
{
  public:

    ActionNodeBase(const std::string& name, const NodeParameters& parameters = NodeParameters());
    ~ActionNodeBase() override = default;

    virtual NodeStatus executeTick() override;

    virtual NodeType type() const override final
    {
        return NodeType::ACTION;
    }
};

class SyncActionNode : public ActionNodeBase
{
  public:

    SyncActionNode(const std::string& name, const NodeParameters& parameters = NodeParameters());
    ~SyncActionNode() override = default;

    virtual NodeStatus executeTick() override;

    virtual void halt() override final // don't need to override this
    {
        setStatus(NodeStatus::IDLE);
    }
};

class SimpleActionNode : public ActionNodeBase
{
  public:
    typedef std::function<NodeStatus(TreeNode&)> TickFunctor;

    // Constructor: you must provide the function to call when tick() is invoked
    SimpleActionNode(const std::string& name, TickFunctor tick_functor,
                     const NodeParameters &params = NodeParameters());

    ~SimpleActionNode() override = default;

    virtual void halt() override
    {
        // not supported
    }

  protected:
    virtual NodeStatus tick() override;

    TickFunctor tick_functor_;
};

class AsyncActionNode : public ActionNodeBase
{
  public:

    AsyncActionNode(const std::string& name, const NodeParameters& parameters = NodeParameters());
    virtual ~AsyncActionNode() override;

    // This method triggers the TickEngine. Do NOT remove the "final" keyword.
    virtual NodeStatus executeTick() override final;

    void stopAndJoinThread();

  protected:

    // The method that is going to be executed by the thread
    void waitForTick();

    // The thread that will execute the node
    std::thread thread_;

    // Node semaphore to simulate the tick
    // (and to synchronize fathers and children)
    TickEngine tick_engine_;

    std::atomic<bool> loop_;
};

// Why is the name "ActionNode" deprecated?
//
// ActionNode was renamed "AsyncActionNode" because it's implementation, i.e. one thread
// per action, is too wastefull in terms of resources.
// The name ActionNode seems to imply that it is the default Node to use for Actions.
// But, in my opinion, the user should think twice if using it and carefully consider the cost of abstraction.
// For this reason, AsyncActionNode is a much better name.


// The right class to use for synchronous Actions is SyncActionBase
[[deprecated]]
typedef AsyncActionNode ActionNode;

class CoroActionNode : public ActionNodeBase
{
  public:
    // Constructor
    CoroActionNode(const std::string& name, const NodeParameters& parameters = NodeParameters());
    virtual ~CoroActionNode() override;

    void setStatusRunningAndYield();

    // This method triggers the TickEngine. Do NOT remove the "final" keyword.
    virtual NodeStatus executeTick() override final;

    void halt() override;

  protected:

    struct Pimpl; // The Pimpl idiom
    std::unique_ptr<Pimpl> _p;

};


}   //end namespace

#endif