PeerStreamer

#ifndef _REPOCLIENT_IMPL_H

#define _REPOCLIENT_IMPL_H

/** @file repoclient_impl.h

 *

 * Local header file defining nuts 'n bolts for the repoclient implementation.

 *

 */

#define _GNU_SOURCE

#include        <stdio.h>

#include        <stdlib.h>

#include        <string.h>

#include        <math.h>

#include        <event2/event.h>

#include        <event2/buffer.h>

#include        <event2/http.h>

#include        <event2/http_struct.h>

#include        <grapes.h>

#include        <grapes_log.h>

#include        <mon.h>                // for MeasurementRecord

#include        <repoclient.h>

#define REPOSERVER_MAGIC        0xAABB

#define PUBLISH_BUFFER_SIZE        1024

/** Struct maintaining streambuffer data. Used internally */

struct streambuffer {

        FILE *stream;

        char *buffer;

        size_t len;

};

extern struct streambuffer publish_streambuffer;

struct deferred_publish;

/** Internal structure to store a reposerver's connection data */

struct reposerver {

        /** IP Address part of the server URI */

        char *address;

        /** Port part of the server URI */

        unsigned short port;

        /** http connection from libevent */

        struct evhttp_connection *evhttp_conn;

        /** publish_delay */

        int publish_delay;

        /** publish buffer */

        struct deferred_publish *publish_buffer;

        /** publish buffer counter */

        int publish_buffer_entries;

        /* deferred publishs in transit */

        struct deferred_publish *in_transit;

        /** in-transit buffer counter */

        int in_transit_entries;

        /** magic value for paranoid people */

        int magic;

};

/** Holds callback address and id for HTTP response callbacks, as well as a data field */

typedef struct {

        /** callback address */

        void *cb;

        /** callback user argument */

        void *cbarg;

        /** id of the request */

        HANDLE id;

        /** the server this request belongs to */

        struct reposerver *server;

        /** arbitrary data field (e.g. used for maxresults) */

        int data;

} request_data;

/** Internal structure for holding batch publish records */

struct deferred_publish {

        MeasurementRecord r;

        request_data *requestdata;

};

/** Helper callback for operations returning a string-list (i.e. char **) to be called by libevent

  @param req the http request struct

  @param arg we store the pointer to the corresponding request_data

*/

void _stringlist_callback(struct evhttp_request *req,void *arg);

/** Check the validity (i.e. it is open) of a repoclient handle 

  @param h the handle

  @param fn name of the function check_handle is called from (to aid error reporting)

  @return 1 if the handle is valid, 0 if not

*/

int check_handle(HANDLE h, const char *fn);

/** Helper for HTTP GET queries 

  @param uri request string

  @param callback callback function

  @param cb_arg callback arg

*/

void make_request(const char *uri, void (*callback)(struct evhttp_request *, void *), void *cb_arg);

/** Helper for HTTP POST queries 

  @param uri request string

  @param data POST DATA (as 0-terminated string)

  @param callback callback function

  @param cb_arg callback arg

  @retun 0 on success, <0 on error

*/

int make_post_request(const char *uri, const char *data, void (*callback)(struct evhttp_request *, void *), void *cb_arg);

/** Parse a measurement record from the HTTP encoding 

  @param line the line as sent by the repo server

  @return the record parsed or NULL if invalid. The record is dynamically allocated and needs to be freed by the caller.

*/

MeasurementRecord parse_measurementrecord(const char *line);

/** print a Constraint array according to the HTTP encoding used in the reposerver communication 

  @param ranks array of Constraint s

  @param len length of the constraints array

  @return textual representation of the constraint struct in a static buffer

*/

const char *constraints2str(Constraint *constraints, int len);

/** print a Ranking array according to the HTTP encoding used in the reposerver communication 

  @param ranks array of Ranking s

  @param len length of the ranks array

  @return textual representation of the rankings struct in a static buffer

*/

const char *rankings2str(Ranking *ranks, int len);

/** print a MeasurementRecord 

  @param r the record

  @return pointer to an internal buffer containing string representation

*/

const char *encode_measurementrecord(const MeasurementRecord *r);

/** free the contents of a MeasurementRecord 

  @param r pointer to the record

*/

void free_measurementrecord(MeasurementRecord *r);

/** copy a measurementrecord for deferred publishing (by strdup-ing string elements)

  @param dst destination MR address

  @param src source MR

*/

void copy_measurementrecord(MeasurementRecord *dst, const MeasurementRecord *src);

#endif