urdf_parser.cpp

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/* Author: Wim Meeussen */

#include <boost/algorithm/string.hpp>
#include <ros/console.h>
#include <vector>
#include "urdf_parser/urdf_parser.h"

namespace urdf{



boost::shared_ptr<ModelInterface>  parseURDF(const std::string &xml_string)
{
  boost::shared_ptr<ModelInterface> model(new ModelInterface);
  model->clear();

  TiXmlDocument xml_doc;
  xml_doc.Parse(xml_string.c_str());

  TiXmlElement *robot_xml = xml_doc.FirstChildElement("robot");
  if (!robot_xml)
  {
    ROS_ERROR("Could not find the 'robot' element in the xml file");
    model.reset();
    return model;
  }

  // Get robot name
  const char *name = robot_xml->Attribute("name");
  if (!name)
  {
    ROS_ERROR("No name given for the robot.");
    model.reset();
    return model;
  }
  model->name_ = std::string(name);

  // Get all Material elements
  for (TiXmlElement* material_xml = robot_xml->FirstChildElement("material"); material_xml; material_xml = material_xml->NextSiblingElement("material"))
  {
    boost::shared_ptr<Material> material;
    material.reset(new Material);

    if (material->initXml(material_xml))
    {
      if (model->getMaterial(material->name))
      {
        ROS_ERROR("material '%s' is not unique.", material->name.c_str());
        material.reset();
        model.reset();
        return model;
      }
      else
      {
        model->materials_.insert(make_pair(material->name,material));
        ROS_DEBUG("successfully added a new material '%s'", material->name.c_str());
      }
    }
    else
    {
      ROS_ERROR("material xml is not initialized correctly");
      material.reset();
      model.reset();
      return model;
    }
  }

  // Get all Link elements
  for (TiXmlElement* link_xml = robot_xml->FirstChildElement("link"); link_xml; link_xml = link_xml->NextSiblingElement("link"))
  {
    boost::shared_ptr<Link> link;
    link.reset(new Link);

    if (link->initXml(link_xml))
    {
      if (model->getLink(link->name))
      {
        ROS_ERROR("link '%s' is not unique.", link->name.c_str());
        model.reset();
        return model;
      }
      else
      {
        // set link visual material
        ROS_DEBUG("setting link '%s' material", link->name.c_str());
        if (link->visual)
        {
          if (!link->visual->material_name.empty())
          {
            if (model->getMaterial(link->visual->material_name))
            {
              ROS_DEBUG("setting link '%s' material to '%s'", link->name.c_str(),link->visual->material_name.c_str());
              link->visual->material = model->getMaterial( link->visual->material_name.c_str() );
            }
            else
            {
              if (link->visual->material)
              {
                ROS_DEBUG("link '%s' material '%s' defined in Visual.", link->name.c_str(),link->visual->material_name.c_str());
                model->materials_.insert(make_pair(link->visual->material->name,link->visual->material));
              }
              else
              {
                ROS_ERROR("link '%s' material '%s' undefined.", link->name.c_str(),link->visual->material_name.c_str());
                model.reset();
                return model;
              }
            }
          }
        }

        model->links_.insert(make_pair(link->name,link));
        ROS_DEBUG("successfully added a new link '%s'", link->name.c_str());
      }
    }
    else
    {
      ROS_ERROR("link xml is not initialized correctly");
      model.reset();
      return model;
    }
  }
  if (model->links_.empty()){
    ROS_ERROR("No link elements found in urdf file");
    model.reset();
    return model;
  }

  // Get all Joint elements
  for (TiXmlElement* joint_xml = robot_xml->FirstChildElement("joint"); joint_xml; joint_xml = joint_xml->NextSiblingElement("joint"))
  {
    boost::shared_ptr<Joint> joint;
    joint.reset(new Joint);

    if (joint->initXml(joint_xml))
    {
      if (model->getJoint(joint->name))
      {
        ROS_ERROR("joint '%s' is not unique.", joint->name.c_str());
        model.reset();
        return model;
      }
      else
      {
        model->joints_.insert(make_pair(joint->name,joint));
        ROS_DEBUG("successfully added a new joint '%s'", joint->name.c_str());
      }
    }
    else
    {
      ROS_ERROR("joint xml is not initialized correctly");
      model.reset();
      return model;
    }
  }


  // every link has children links and joints, but no parents, so we create a
  // local convenience data structure for keeping child->parent relations
  std::map<std::string, std::string> parent_link_tree;
  parent_link_tree.clear();

  // building tree: name mapping
  if (!model->initTree(parent_link_tree))
  {
    ROS_ERROR("failed to build tree");
    model.reset();
    return model;
  }

  // find the root link
  if (!model->initRoot(parent_link_tree))
  {
    ROS_ERROR("failed to find root link");
    model.reset();
    return model;
  }
 
  return model;
}

}