action_node.cpp

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/* Copyright (C) 2015-2018 Michele Colledanchise -  All Rights Reserved
 * Copyright (C) 2018-2023 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.
*/
 
#define MINICORO_IMPL
#include "minicoro/minicoro.h"
#include "behaviortree_cpp/action_node.h"
 
using namespace BT;
 
ActionNodeBase::ActionNodeBase(const std::string& name, const NodeConfig& config)
  : LeafNode::LeafNode(name, config)
{}
 
//-------------------------------------------------------
 
SimpleActionNode::SimpleActionNode(const std::string& name,
                                   SimpleActionNode::TickFunctor tick_functor,
                                   const NodeConfig& config)
  : SyncActionNode(name, config), tick_functor_(std::move(tick_functor))
{}
 
NodeStatus SimpleActionNode::tick()
{
  NodeStatus prev_status = status();
 
  if(prev_status == NodeStatus::IDLE)
  {
    setStatus(NodeStatus::RUNNING);
    prev_status = NodeStatus::RUNNING;
  }
 
  NodeStatus status = tick_functor_(*this);
  if(status != prev_status)
  {
    setStatus(status);
  }
  return status;
}
 
//-------------------------------------------------------
 
SyncActionNode::SyncActionNode(const std::string& name, const NodeConfig& config)
  : ActionNodeBase(name, config)
{}
 
NodeStatus SyncActionNode::executeTick()
{
  auto stat = ActionNodeBase::executeTick();
  if(stat == NodeStatus::RUNNING)
  {
    throw LogicError("SyncActionNode MUST never return RUNNING");
  }
  return stat;
}
 
//-------------------------------------
 
struct CoroActionNode::Pimpl
{
  mco_coro* coro = nullptr;
  mco_desc desc;
};
 
void CoroEntry(mco_coro* co)
{
  static_cast<CoroActionNode*>(co->user_data)->tickImpl();
}
 
CoroActionNode::CoroActionNode(const std::string& name, const NodeConfig& config)
  : ActionNodeBase(name, config), _p(new Pimpl)
{}
 
CoroActionNode::~CoroActionNode()
{
  destroyCoroutine();
}
 
void CoroActionNode::setStatusRunningAndYield()
{
  setStatus(NodeStatus::RUNNING);
  mco_yield(_p->coro);
}
 
NodeStatus CoroActionNode::executeTick()
{
  // create a new coroutine, if necessary
  if(_p->coro == nullptr)
  {
    // First initialize a `desc` object through `mco_desc_init`.
    _p->desc = mco_desc_init(CoroEntry, 0);
    _p->desc.user_data = this;
 
    mco_result res = mco_create(&_p->coro, &_p->desc);
    if(res != MCO_SUCCESS)
    {
      throw RuntimeError("Can't create coroutine");
    }
  }
 
  //------------------------
  // execute the coroutine
  mco_resume(_p->coro);
  //------------------------
 
  // check if the coroutine finished. In this case, destroy it
  if(mco_status(_p->coro) == MCO_DEAD)
  {
    destroyCoroutine();
  }
 
  return status();
}
 
void CoroActionNode::tickImpl()
{
  setStatus(TreeNode::executeTick());
}
 
void CoroActionNode::halt()
{
  destroyCoroutine();
  resetStatus();  // might be redundant
}
 
void CoroActionNode::destroyCoroutine()
{
  if(_p->coro)
  {
    mco_result res = mco_destroy(_p->coro);
    if(res != MCO_SUCCESS)
    {
      throw RuntimeError("Can't destroy coroutine");
    }
    _p->coro = nullptr;
  }
}
 
bool StatefulActionNode::isHaltRequested() const
{
  return halt_requested_.load();
}
 
NodeStatus StatefulActionNode::tick()
{
  const NodeStatus prev_status = status();
 
  if(prev_status == NodeStatus::IDLE)
  {
    NodeStatus new_status = onStart();
    if(new_status == NodeStatus::IDLE)
    {
      throw LogicError("StatefulActionNode::onStart() must not return IDLE");
    }
    return new_status;
  }
  //------------------------------------------
  if(prev_status == NodeStatus::RUNNING)
  {
    NodeStatus new_status = onRunning();
    if(new_status == NodeStatus::IDLE)
    {
      throw LogicError("StatefulActionNode::onRunning() must not return IDLE");
    }
    return new_status;
  }
  return prev_status;
}
 
void StatefulActionNode::halt()
{
  halt_requested_.store(true);
  if(status() == NodeStatus::RUNNING)
  {
    onHalted();
  }
  resetStatus();  // might be redundant
}
 
NodeStatus BT::ThreadedAction::executeTick()
{
  using lock_type = std::unique_lock<std::mutex>;
  //send signal to other thread.
  // The other thread is in charge for changing the status
  if(status() == NodeStatus::IDLE)
  {
    setStatus(NodeStatus::RUNNING);
    halt_requested_ = false;
    thread_handle_ = std::async(std::launch::async, [this]() {
      try
      {
        auto status = tick();
        if(!isHaltRequested())
        {
          setStatus(status);
        }
      }
      catch(std::exception&)
      {
        std::cerr << "\nUncaught exception from tick(): [" << registrationName() << "/"
                  << name() << "]\n"
                  << std::endl;
        // Set the exception pointer and the status atomically.
        lock_type l(mutex_);
        exptr_ = std::current_exception();
        setStatus(BT::NodeStatus::IDLE);
      }
      emitWakeUpSignal();
    });
  }
 
  lock_type l(mutex_);
  if(exptr_)
  {
    // The official interface of std::exception_ptr does not define any move
    // semantics. Thus, we copy and reset exptr_ manually.
    const auto exptr_copy = exptr_;
    exptr_ = nullptr;
    std::rethrow_exception(exptr_copy);
  }
  return status();
}
 
void ThreadedAction::halt()
{
  halt_requested_.store(true);
 
  if(thread_handle_.valid())
  {
    thread_handle_.wait();
  }
  thread_handle_ = {};
  resetStatus();  // might be redundant
}