Function loadXmlAndResolveTreeId

src/bt_factory.cpp:58–93

Load XML into parser and resolve which tree to instantiate. Returns the resolved tree ID (may be empty if parser should use default).

// Load XML into parser and resolve which tree to instantiate.
// Returns the resolved tree ID (may be empty if parser should use default).
std::string loadXmlAndResolveTreeId(Parser* parser, const std::string& main_tree_ID,
                                    const std::function<void()>& load_func)
{
  // When the main tree couldn't be determined from the raw XML
  // (e.g. <BehaviorTree> without an ID), snapshot registered trees
  // before loading so we can diff afterwards.
  std::set<std::string> before_set;
  if(main_tree_ID.empty())
  {
    const auto before = parser->registeredBehaviorTrees();
    before_set.insert(before.begin(), before.end());
  }

  load_func();

  // Try to identify the newly added tree by diffing.
  if(main_tree_ID.empty())
  {
    const auto after = parser->registeredBehaviorTrees();
    std::string single_new_tree;
    int new_count = 0;
    for(const auto& name : after)
    {
      if(before_set.count(name) == 0)
      {
        single_new_tree = name;
        new_count++;
      }
    }
    if(new_count == 1)
    {
      return single_new_tree;
    }
  }
  return main_tree_ID;
}

}  // namespace