bt_observer.h

#ifndef BT_OBSERVER_H
#define BT_OBSERVER_H
 
#include "behaviortree_cpp/loggers/abstract_logger.h"
 
#include <cstring>
 
namespace BT
{
 
/**
 * @brief The TreeObserver is used to collect statistics about which nodes
 * are executed and their returned status.
 *
 * It is particularly useful to create unit tests, since if allow to
 * determine if a certain transition happened as expected, in a non intrusive way.
 */
class TreeObserver : public StatusChangeLogger
{
public:
  TreeObserver(const BT::Tree& tree);
  ~TreeObserver() override;
 
  TreeObserver(const TreeObserver&) = delete;
  TreeObserver& operator=(const TreeObserver&) = delete;
  TreeObserver(TreeObserver&&) = delete;
  TreeObserver& operator=(TreeObserver&&) = delete;
 
  virtual void flush() override
  {}
 
  void resetStatistics();
 
  struct NodeStatistics
  {
    // Last __valid__ result, either SUCCESS or FAILURE
    NodeStatus last_result = NodeStatus::IDLE;
    // Last status. Can be any status, including IDLE or SKIPPED
    NodeStatus current_status = NodeStatus::IDLE;
 
    // count status transitions, excluding transition to IDLE
    unsigned transitions_count = 0;
    // count number of transitions to SUCCESS
    unsigned success_count = 0;
    // count number of transitions to FAILURE
    unsigned failure_count = 0;
    // count number of transitions to SKIPPED
    unsigned skip_count = 0;
 
    Duration last_timestamp = {};
  };
 
  // find the statistics of a node, based on its path
  const NodeStatistics& getStatistics(const std::string& path) const;
 
  // find the statistics of a node, based on its TreeNode::UID()
  const NodeStatistics& getStatistics(uint16_t uid) const;
 
  // all statistics
  const std::unordered_map<uint16_t, NodeStatistics>& statistics() const;
 
  // path to UID map
  const std::unordered_map<std::string, uint16_t>& pathToUID() const;
 
  const std::map<uint16_t, std::string>& uidToPath() const;
 
private:
  std::unordered_map<uint16_t, NodeStatistics> _statistics;
  std::unordered_map<std::string, uint16_t> _path_to_uid;
  std::map<uint16_t, std::string> _uid_to_path;
 
  virtual void callback(Duration timestamp, const TreeNode& node, NodeStatus prev_status,
                        NodeStatus status) override;
};
 
}  // namespace BT
 
#endif  // BT_OBSERVER_H