subscriber.h

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#ifndef MESSAGE_TRANSPORT_SUBSCRIBER_H
#define MESSAGE_TRANSPORT_SUBSCRIBER_H

#include <ros/ros.h>
#include "message_transport/transport_hints.h"
#include "message_transport/subscriber_impl.h"

namespace message_transport {

        class Subscriber
        {
                public:
                        Subscriber() {}
                        Subscriber(ros::NodeHandle& nh);

                        std::string getTopic() const;

                        uint32_t getNumPublishers() const;

                        void shutdown();

                        operator void*() const;
                        bool operator< (const Subscriber& rhs) const { return impl_ <  rhs.impl_; }
                        bool operator!=(const Subscriber& rhs) const { return impl_ != rhs.impl_; }
                        bool operator==(const Subscriber& rhs) const { return impl_ == rhs.impl_; }

                        template <class M>
                                int do_subscribe(ros::NodeHandle& nh, 
                                                const std::string & package_name, const std::string & class_name, 
                                                const std::string& base_topic, uint32_t queue_size,
                                                const boost::function<void(const typename M::ConstPtr&)>& callback,
                                                const ros::VoidPtr& tracked_object, const TransportHints& transport_hints)
                                {
                                        // Tell plugin to subscribe.
                                        impl_.reset(new SubscriberImpl<M>(package_name,class_name));
                                        // Load the plugin for the chosen transport.
                                        impl_.get()->reset(transport_hints);

                                        // Try to catch if user passed in a transport-specific topic as base_topic.
                                        std::string clean_topic = ros::names::clean(base_topic);
                                        size_t found = clean_topic.rfind('/');
                                        if (found != std::string::npos) {
                                                std::string transport = clean_topic.substr(found+1);
                                                std::string plugin_name = SubscriberPluginGen::getLookupName(transport);
                                                std::vector<std::string> plugins = impl_->getDeclaredClasses();
                                                if (std::find(plugins.begin(), plugins.end(), plugin_name) != plugins.end()) {
                                                        std::string real_base_topic = clean_topic.substr(0, found);
                                                        ROS_WARN("[message_transport] It looks like you are trying to subscribe directly to a "
                                                                        "transport-specific image topic '%s', in which case you will likely get a connection "
                                                                        "error. Try subscribing to the base topic '%s' instead with parameter ~message_transport "
                                                                        "set to '%s' (on the command line, _message_transport:=%s). "
                                                                        "See http://ros.org/wiki/message_transport for details.",
                                                                        clean_topic.c_str(), real_base_topic.c_str(), transport.c_str(), transport.c_str());
                                                }
                                        }

                                        impl_->getTemplateSubscriber<M>()->subscribe(nh, base_topic, queue_size, callback, tracked_object, transport_hints);
                                        return 0;
                                }

                private:

                        typedef boost::shared_ptr<SubscriberImplGen> ImplPtr;

                        ImplPtr impl_;

        };

} //namespace message_transport

#endif