mjpeg_server.h

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#ifndef MJPEG_SERVER_H_
#define MJPEG_SERVER_H_

#include <ros/ros.h>
#include <sensor_msgs/Image.h>
#include <image_transport/image_transport.h>
#include <cv_bridge/cv_bridge.h>

#include <boost/thread/mutex.hpp>
#include <boost/thread/condition.hpp>

/*
 * Maximum number of server sockets (i.e. protocol families) to listen.
 */
#define MAX_NUM_SOCKETS    100
#define IO_BUFFER     256
#define BUFFER_SIZE   1024

namespace mjpeg_server
{

/* the webserver determines between these values for an answer */
typedef enum
{
  A_UNKNOWN, A_STREAM, A_SNAPSHOT,
} answer_t;

/*
 * the client sends information with each request
 * this structure is used to store the important parts
 */
typedef struct
{
  answer_t type;
  char *parameter;
  char *client;
  char *credentials;
} request;

/* the iobuffer structure is used to read from the HTTP-client */
typedef struct
{
  int level; /* how full is the buffer */
  char buffer[IO_BUFFER]; /* the data */
} iobuffer;

class ImageBuffer
{
public:
  ImageBuffer()
  {
  }
  sensor_msgs::Image msg;
  boost::condition_variable condition_;
  boost::mutex mutex_;
};

class MJPEGServer
{
public:
  MJPEGServer(ros::NodeHandle& node);

  virtual ~MJPEGServer();

  void execute();

  void spin();

  void stop();

  void cleanUp();

  void client(int fd);

private:
  typedef std::map<std::string, ImageBuffer*> ImageBufferMap;
  typedef std::map<std::string, image_transport::Subscriber> ImageSubscriberMap;
  typedef std::map<std::string, size_t> ImageSubscriberCountMap;
  typedef std::map<std::string, std::string> ParameterMap;

  std::string header;

  ImageBuffer* getImageBuffer(const std::string& topic);

  void imageCallback(const sensor_msgs::ImageConstPtr& msg, const std::string& topic);

  void invertImage(const cv::Mat& input, cv::Mat& output);

  void sendError(int fd, int which, const char *message);

  void sendStream(int fd, const char *parameter);

  void sendSnapshot(int fd, const char *parameter);

  void initIOBuffer(iobuffer *iobuf);

  void initRequest(request *req);

  void freeRequest(request *req);

  int readWithTimeout(int fd, iobuffer *iobuf, char *buffer, size_t len, int timeout);

  int readLineWithTimeout(int fd, iobuffer *iobuf, char *buffer, size_t len, int timeout);

  void decodeBase64(char *data);

  int hexCharToInt(char in);

  int unescape(char *string);

  void splitString(const std::string& str, std::vector<std::string>& tokens, const std::string& delimiter = " ");

  int stringToInt(const std::string& str, const int default_value = 0);

  void decodeParameter(const std::string& parameter, ParameterMap& parameter_map);

  void decreaseSubscriberCount(const std::string topic);

  void increaseSubscriberCount(const std::string topic);

  void unregisterSubscriberIfPossible(const std::string topic);
  
  ros::NodeHandle node_;
  image_transport::ImageTransport image_transport_;
  int port_;

  int sd[MAX_NUM_SOCKETS];
  int sd_len;

  bool stop_requested_;
  char* www_folder_;

  ImageBufferMap image_buffers_;
  ImageSubscriberMap image_subscribers_;
  ImageSubscriberCountMap image_subscribers_count_;
  boost::mutex image_maps_mutex_;

};

}

#endif