service_publication.cpp

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#include "ros/service_publication.h"
#include "ros/service_client_link.h"
#include "ros/connection.h"
#include "ros/callback_queue_interface.h"

#include <boost/bind.hpp>

#include <std_msgs/String.h>

namespace ros
{

ServicePublication::ServicePublication(const std::string& name, const std::string &md5sum, const std::string& data_type, const std::string& request_data_type,
                             const std::string& response_data_type, const ServiceCallbackHelperPtr& helper, CallbackQueueInterface* callback_queue,
                             const VoidConstPtr& tracked_object)
: name_(name)
, md5sum_(md5sum)
, data_type_(data_type)
, request_data_type_(request_data_type)
, response_data_type_(response_data_type)
, helper_(helper)
, dropped_(false)
, callback_queue_(callback_queue)
, has_tracked_object_(false)
, tracked_object_(tracked_object)
{
  if (tracked_object)
  {
    has_tracked_object_ = true;
  }
}

ServicePublication::~ServicePublication()
{
  drop();
}

void ServicePublication::drop()
{
  // grab a lock here, to ensure that no subscription callback will
  // be invoked after we return
  {
    boost::mutex::scoped_lock lock(client_links_mutex_);
    dropped_ = true;
  }

  dropAllConnections();

  callback_queue_->removeByID((uint64_t)this);
}

class ServiceCallback : public CallbackInterface
{
public:
  ServiceCallback(const ServiceCallbackHelperPtr& helper, const boost::shared_array<uint8_t>& buf, size_t num_bytes, const ServiceClientLinkPtr& link, bool has_tracked_object, const VoidConstWPtr& tracked_object)
  : helper_(helper)
  , buffer_(buf)
  , num_bytes_(num_bytes)
  , link_(link)
  , has_tracked_object_(has_tracked_object)
  , tracked_object_(tracked_object)
  {
  }

  virtual CallResult call()
  {
    if (link_->getConnection()->isDropped())
    {
      return Invalid;
    }

    VoidConstPtr tracker;
    if (has_tracked_object_)
    {
      tracker = tracked_object_.lock();

      if (!tracker)
      {
        SerializedMessage res = serialization::serializeServiceResponse<uint32_t>(false, 0);
        link_->processResponse(false, res);
        return Invalid;
      }
    }

    ServiceCallbackHelperCallParams params;
    params.request = SerializedMessage(buffer_, num_bytes_);
    params.connection_header = link_->getConnection()->getHeader().getValues();
    try
    {

      bool ok = helper_->call(params);
      if (ok != 0)
      {
        link_->processResponse(true, params.response);
      }
      else
      {
        SerializedMessage res = serialization::serializeServiceResponse<uint32_t>(false, 0);
        link_->processResponse(false, res);
      }
    }
    catch (std::exception& e)
    {
      ROS_ERROR("Exception thrown while processing service call: %s", e.what());
      std_msgs::String error_string;
      error_string.data = e.what();
      SerializedMessage res = serialization::serializeServiceResponse(false, error_string);
      link_->processResponse(false, res);
      return Invalid;
    }

    return Success;
  }

private:
  ServiceCallbackHelperPtr helper_;
  boost::shared_array<uint8_t> buffer_;
  uint32_t num_bytes_;
  ServiceClientLinkPtr link_;
  bool has_tracked_object_;
  VoidConstWPtr tracked_object_;
};

void ServicePublication::processRequest(boost::shared_array<uint8_t> buf, size_t num_bytes, const ServiceClientLinkPtr& link)
{
  CallbackInterfacePtr cb(boost::make_shared<ServiceCallback>(helper_, buf, num_bytes, link, has_tracked_object_, tracked_object_));
  callback_queue_->addCallback(cb, (uint64_t)this);
}

void ServicePublication::addServiceClientLink(const ServiceClientLinkPtr& link)
{
  boost::mutex::scoped_lock lock(client_links_mutex_);

  client_links_.push_back(link);
}

void ServicePublication::removeServiceClientLink(const ServiceClientLinkPtr& link)
{
  boost::mutex::scoped_lock lock(client_links_mutex_);

  V_ServiceClientLink::iterator it = std::find(client_links_.begin(), client_links_.end(), link);
  if (it != client_links_.end())
  {
    client_links_.erase(it);
  }
}

void ServicePublication::dropAllConnections()
{
  // Swap our client_links_ list with a local one so we can only lock for a short period of time, because a
  // side effect of our calling drop() on connections can be re-locking the client_links_ mutex
  V_ServiceClientLink local_links;

  {
    boost::mutex::scoped_lock lock(client_links_mutex_);

    local_links.swap(client_links_);
  }

  for (V_ServiceClientLink::iterator i = local_links.begin();
           i != local_links.end(); ++i)
  {
    (*i)->getConnection()->drop(Connection::Destructing);
  }
}

} // namespace ros