/*

  Copyright 2009 Nathan Phillip Brink, Ethan Zonca, Matthew Orlando

  This file is a part of DistRen.

  DistRen is free software: you can redistribute it and/or modify

  it under the terms of the GNU Affero General Public License as published by

  the Free Software Foundation, either version 3 of the License, or

  (at your option) any later version.

  DistRen is distributed in the hope that it will be useful,

  but WITHOUT ANY WARRANTY; without even the implied warranty of

  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License

  along with DistRen.  If not, see <http://www.gnu.org/licenses/>.

*/

/* This file contains the code which both processes (renders) jobs as a slave, and the code which distributes frames to slaves after receiving them from the client portion of the codebase. */

#include "asprintf.h"

#include "distrenjob.h"

#include "execio.h"

#include "listen.h"

#include "options.h"

#include "protocol.h"

#include "slavefuncs.h"

#include <confuse.h>

#include <malloc.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <time.h>

#include <unistd.h>

#include <libxml/xmlmemory.h>

#include <libxml/parser.h>

#include <libxml/tree.h>

#include <libxml/encoding.h>

#include <libxml/xmlwriter.h>

#include <libxml/xmlreader.h>

/* local defs */

#define NUMBER_ELEVEN 11

/* ******************* Structs ************************ */

struct general_info

{

  struct distrenjob head;

  struct distrend_config *config;

  int jobs_in_queue;

  unsigned int free_clients;

  unsigned int rendering_clients;

  unsigned int total_finished_jobs;

  unsigned int total_frames_rendered;

  unsigned int highest_jobnum;

  int hibernate;

  time_t timestamp;

  unsigned long total_render_power;

  unsigned long total_priority_pieces;

};

/*

  internally defined funcs's prototypes @TODO: Make all functions nice and proper 

*/

void distrenjob_remove(struct general_info *, struct distrenjob *bj);

struct distrenjob *distrenjob_get(struct distrenjob *head, jobnum_t jobnum);

int distrenjob_enqueue(struct general_info *, struct distrenjob *job);

int mortition(struct general_info *, struct distrenjob *job);

int update_xml_joblist(struct general_info *);

int createQueueFromXML(struct distrenjob *head);

int reCreateQueueFromXML(struct distrenjob *head, xmlDocPtr doc, xmlNodePtr current);

void update_general_info(struct general_info*);

int import_general_info(struct general_info*);

int updateJobStatsXML(struct distrenjob *job);

/* ********************** Functions ************************* */

/** Dumps all data in RAM to an xml file (such as current jobs, etc) which is parsed by start_data. Remember to invoke this before shutting down! */

int xml_dump()

{

  return 0;

}

/**

   Performs command stored in a client's request.

*/

int distrend_do()

{

  return 0;

}

/**

   Frees the action

*/

void distrend_action_free()

{

}

/** 

    Fill variables at startup from XML dumps or defaults

 */

int start_data(struct general_info *general_info, char *datadir)

{

  struct stat buffer;

  /**

     defaults

   */

  memset(&general_info->head, '\0', sizeof(struct distrenjob));

  general_info->head.priority = 0;

  general_info->jobs_in_queue = 0;

  general_info->free_clients = 0;

  general_info->rendering_clients = 0;

  general_info->total_finished_jobs = 0;

  general_info->total_frames_rendered = 0;

  general_info->highest_jobnum = 0;

  general_info->hibernate = 0;

  general_info->timestamp = 0;

  general_info->total_render_power = 0;

  general_info->total_priority_pieces = 0;

  fprintf(stderr, "Initialized default global and queue states\n");

  if(stat("general_info.xml", &buffer) == 0)

    {

      fprintf(stderr, "previous state file found, loading:\n");

      fprintf(stderr, "Parsing XML files and restoring previous state...\n");

      if(import_general_info(general_info))

	fprintf(stderr, "FAILURE\n");

      fprintf(stderr, "Restoring queue...\n");

      if(createQueueFromXML(&general_info->head))

	fprintf(stderr, "FAILURE\n");

      fprintf(stderr, "done\n");

    }

  return 0;

}

/** Finish-Setter: Sets a frame to the "completed" status.*/

void finish_frame(struct general_info *geninfo, struct distrenjob *distrenjob, int frame)

{

  distrenjob->frameset[frame].status = FRAMESETSTATUS_DONE;

  distrenjob->total_render_time = distrenjob->total_render_time + (clock() - distrenjob->frameset[frame].start_time);

  distrenjob->completed_frames ++;

  distrenjob->assigned_frames --;

  geninfo->total_frames_rendered ++; /*< Increase total frames var for stats */

  update_general_info(geninfo);

  updateJobStatsXML(distrenjob);

}

/**

   checks to see if a job is actually done.

   - scans the folder of the job to make sure all output files are present

*/

int mortition(struct general_info *geninfo, struct distrenjob *job)

{

  short int isJobDone;

  int counter;

  char *path_and_number;

  struct stat buffer;

  isJobDone = 1; // set isJobDone to true

  for(counter = 0; counter < job->total_frames; counter++)

    {

      _distren_asprintf(&path_and_number, "stor/job%d/out/%d.%s", job->jobnum, job->frameset[counter].num, job->output_format);

      if(stat(path_and_number, &buffer) == -1)

        {

          job->frameset[counter].status = FRAMESETSTATUS_UNASSIGNED;

          job->completed_frames--;

          geninfo->total_frames_rendered--;

          isJobDone = 0; // if a missing frame is found, set isJobDone to false

        }

    }

  if(isJobDone) // if all frames were accounted for

    {

      distrenjob_remove(geninfo, job);

      distrenjob_free(&job);

      geninfo->jobs_in_queue --;

      update_xml_joblist(geninfo);

    }

  else{

    job->prev_frame_index = -1; // if the job isn't done, have frame_finder() start from the first frame, allowing it to see the frames that are now unassigned

  }

  update_general_info(geninfo);

  return 0;

}

/** scans the frames of a job to initialize a job after server */

/* returns 1 if the job is completely done and there are no missing frames */

/* returns 0 if a missing frame is found */

int restoreJobState(struct distrenjob *job)

{

  short int isJobDone;

  int counter;

  char *path_and_number;

  struct stat buffer;

  isJobDone = 1;

  for(counter = 0; counter < job->total_frames; counter++)

    {

      _distren_asprintf(&path_and_number, "stor/job%d/out/%d.%s", job->jobnum, job->frameset[counter].num, job->output_format);

      if(stat(path_and_number, &buffer) == 0)

        {

          job->frameset[counter].status = FRAMESETSTATUS_ASSIGNED;

          job->completed_frames++;

        }

      else

        isJobDone = 0;

    }

  return isJobDone;

}

/** creates a structure from starting data, then calls another function to actually add that struct to the queue */

int prepare_distrenjob(struct general_info *geninfo, int type, char *name, char *submitter, char *email, int priority, int start_frame, int end_frame, int width, int height)

{

  int counter2;

  int counter;

  int tmp;

  char *path_with_num;

  struct distrenjob *distrenjob;

  tmp = distrenjob_new(&distrenjob);

  if(tmp)

    return 1;

  geninfo->highest_jobnum ++;

  distrenjob->jobnum = geninfo->highest_jobnum;

  distrenjob->type = 1;

  distrenjob->name = name;

  distrenjob->submitter = submitter;

  distrenjob->email = email;

  distrenjob->priority = priority;

  distrenjob->width = width;

  distrenjob->height = height;

  distrenjob->total_frames = (end_frame - start_frame + 1); /* sets the total number of frames in animation for status purposes */

  distrenjob->frameset = malloc(sizeof(struct frameset) * distrenjob->total_frames);

  if(!distrenjob->frameset)

    {

      distrenjob_free(&distrenjob);

      return 1;

    }

  /* prepares all the frames by setting that status to "unassigned" */

  counter2 = start_frame;

  for(counter = 0; counter < distrenjob->total_frames; counter++){

    distrenjob->frameset[counter].num = counter2;

    distrenjob->frameset[counter].status = FRAMESETSTATUS_UNASSIGNED;

    counter2++;

  }

  _distren_asprintf(&path_with_num, "stor/job%d/out/", distrenjob->jobnum);

  fprintf(stderr, "creating dir '%s'", path_with_num);

  /* add job to queue */

  fprintf(stderr, "\nprepare_distrenjob: attempting distrenjob_enqueue()\n");

  distrenjob_enqueue(geninfo, distrenjob);

  geninfo->jobs_in_queue ++;

  fprintf(stderr, "\nprepare_distrenjob: attempting update_xml_joblist()\n");

  update_xml_joblist(geninfo);

  fprintf(stderr, "\nprepare_distrenjob: attempting update_general_info()\n");

  update_general_info(geninfo);

  fprintf(stderr, "\nprepare_distrenjob: attempting updateJobStatsXML()\n");

  updateJobStatsXML(distrenjob);

  return 0;

}

/** distrenjob_enqueue: This function adds the job to the queue based on its priority */

int distrenjob_enqueue(struct general_info *geninfo, struct distrenjob *job)

{

  struct distrenjob *prev_job;

  struct distrenjob *current_job;

  struct distrenjob *head;

  head = &geninfo->head;

  prev_job = head;

  // iterate through linked list of jobs

  for(current_job = head->next; 1; current_job = current_job->next)

  {

	fprintf(stderr, "enqueue loop iteration\n");

    if(current_job == NULL){ // if it has reached the end of the list, add job there

      prev_job->next = job;

      fprintf(stderr, "adding job at end of queue\n");

      break;

    }

    else if(job->priority < current_job->priority){ // if job's priority is less than current_job's priority, insert job

      prev_job->next = job;                        // keep in mind 1 is the highest priority given to jobs, head has a

      job->next = current_job;                     // priority of zero so it will always be before other jobs

      fprintf(stderr, "adding job before jobname: %s\n", current_job->name);

      break;

    }

    prev_job = current_job;

  } /* for(current_job) */

  return 0;

}

/** Changes the priority of an existing (and maybe running) job. @arg head I may end up changing the head if job == head */

int change_job_priority(struct general_info *geninfo, struct distrenjob *job, int new_priority){

  distrenjob_remove(geninfo, job);

  job->priority = new_priority;

  struct distrenjob *current_job;

  struct distrenjob *prev_job;

  prev_job = &geninfo->head;

  if(job->frameset[0].status == FRAMESETSTATUS_UNASSIGNED)

    /**

       if job was not yet started

    */

    {

      distrenjob_enqueue(geninfo, job);

      return 0;

    }

  /**

     iterate through linked list of jobs 

  */

    for(current_job = &geninfo->head;

	current_job != NULL

	  && job->priority > current_job->priority;

	current_job = current_job->next)

      prev_job = current_job;

    prev_job->next = job;

    job->next = current_job;

  update_xml_joblist(geninfo);

  return 0;

}

/**

  Frame Finder: matches your computer up with a lovely frame to render, starts looking at oldest job first

  @TODO: We must return both jobnum and framenum

  @TODO: Add calls in main()

  @return 0 success, other: error

*/

int find_jobframe(struct general_info *geninfo, struct distrenjob **job, struct frameset **frame)

{

  if(geninfo->hibernate)

    return 1;

  unsigned int frame_counter;

  unsigned short int found;

  struct distrenjob *distrenjob_ptr;

  found = 0;

  /* iterate through jobs from first to last */

  for(distrenjob_ptr = geninfo->head.next; distrenjob_ptr && !distrenjob_ptr->hibernate; distrenjob_ptr = distrenjob_ptr->next)

  {

    for(frame_counter = (distrenjob_ptr->prev_frame_index + 1); frame_counter < distrenjob_ptr->total_frames; frame_counter ++)

    {

      if(distrenjob_ptr->frameset[frame_counter].status == FRAMESETSTATUS_UNASSIGNED) // jobframe found

      {

    	found = 1;

    	distrenjob_ptr->frameset[frame_counter].status = FRAMESETSTATUS_ASSIGNED;

    	distrenjob_ptr->frameset[frame_counter].start_time = clock();

    	distrenjob_ptr->assigned_frames++;

    	distrenjob_ptr->prev_frame_index = frame_counter;

    	updateJobStatsXML(distrenjob_ptr);

      }

      if(found)

    	break;

    }

    if(found)

      break;

  }

  if(!found)

    {

      fprintf(stderr, "No more jobs to render\n");

      sleep(1); /*< @todo eliminate the need for this line*/

      return 1;

    }

  *job = distrenjob_ptr;

  *frame = &distrenjob_ptr->frameset[frame_counter];

  return 0;

}

int find_jobframe_from_job(struct distrenjob *distrenjob_ptr, struct distrenjob **job, struct frameset **frame)

{

  unsigned int frame_counter;

  unsigned short int found;

  found = 0;

  for(frame_counter = (distrenjob_ptr->prev_frame_index + 1); frame_counter < distrenjob_ptr->total_frames; frame_counter ++)

  {

    if(distrenjob_ptr->frameset[frame_counter].status == FRAMESETSTATUS_UNASSIGNED) // jobframe found

      {

    	found = 1;

		distrenjob_ptr->frameset[frame_counter].status = FRAMESETSTATUS_ASSIGNED;

		distrenjob_ptr->frameset[frame_counter].start_time = clock();

		distrenjob_ptr->assigned_frames++;

		distrenjob_ptr->prev_frame_index = frame_counter;

		updateJobStatsXML(distrenjob_ptr);

      }

    if(found)

      break;

  }

  if(!found)

    {

      fprintf(stderr, "No more frames in this job number %d", distrenjob_ptr->jobnum);

      distrenjob_ptr->prev_frame_index = frame_counter;

      return 1;

    }

  *job = distrenjob_ptr;

  *frame = &distrenjob_ptr->frameset[frame_counter];

  return 0;

}

// find a frame to render when the job that the last frame was for no longer exists

int find_jobframe_new(struct general_info *geninfo, int rend_pwr, struct distrenjob **job, struct frameset **frame)

{

  if(geninfo->hibernate)

    return 1;

  float power_difference;

  float greatest_power_difference;

  unsigned short int found;

  struct distrenjob *job_to_render;

  struct distrenjob *distrenjob_ptr;

  greatest_power_difference = -10000;

  found = 0;

  /* iterate through jobs from first to last */

  for(distrenjob_ptr = geninfo->head.next;

      distrenjob_ptr && !distrenjob_ptr->hibernate;

      distrenjob_ptr = distrenjob_ptr->next)

  {

	  if(distrenjob_ptr->prev_frame_index < (distrenjob_ptr->total_frames - 1))

	  {

	    /**

	       Why is the number 11 found here again? --ohnobinki

	     */

		  power_difference = (((float)geninfo->total_render_power / (float)geninfo->total_priority_pieces) * (NUMBER_ELEVEN - (float)distrenjob_ptr->priority));

		  power_difference = power_difference - (float)distrenjob_ptr->assigned_render_power;

		  fprintf(stderr, "job num %d\npower difference: %f\n", distrenjob_ptr->jobnum, power_difference);

		  if(power_difference > greatest_power_difference)

		  {

			  job_to_render = distrenjob_ptr;

			  greatest_power_difference = power_difference;

			  found = 1;

		  }

	  }

  }

  if(!found)

    {

      fprintf(stderr, "No more jobs to render\n");

      return 1;

    }

  find_jobframe_from_job(job_to_render, job, frame);

  job_to_render->assigned_render_power = job_to_render->assigned_render_power + rend_pwr;

  return 0;

}

// gets a frame to render from the same job that the previously rendered frame was from

int find_jobframe_again(struct general_info *geninfo, int jobnum, int rend_pwr, struct distrenjob **job, struct frameset **frame)

{

  if(geninfo->hibernate)

    return 1;

  short int found;

  struct distrenjob *distrenjob_ptr;

  distrenjob_ptr = distrenjob_get(&geninfo->head, jobnum);

  // if the job was not found or there are no frames left in the job...

  if(!distrenjob_ptr || distrenjob_ptr->prev_frame_index >= (distrenjob_ptr->total_frames - 1))

    {

      fprintf(stderr, "Job number %d has been finished, finding new job\n", jobnum);

      // if previous job isn't yet finished the render power of the slave is removed from it

      if(distrenjob_ptr)

    	  distrenjob_ptr->assigned_render_power = distrenjob_ptr->assigned_render_power - rend_pwr;

      return find_jobframe_new(geninfo, rend_pwr, job, frame);

    }

  found = 0;

  found = find_jobframe_from_job(distrenjob_ptr, job, frame);

  if(found)

	  find_jobframe_new(geninfo, rend_pwr, job, frame);

  return 0;

}

/** Checks for dead, latent, or stale slaves */

void frame_watchdog(struct distrenjob *distrenjob_head)

{

  struct distrenjob *distrenjob_ptr;

  unsigned int counter;

  for(distrenjob_ptr = distrenjob_head->next; distrenjob_ptr; distrenjob_ptr = distrenjob_ptr->next)

  /* iterate through jobs */

  {

    /* if the job has been started, checks by seeing if either to first or second frame has been started */

    if(distrenjob_ptr->frameset[0].status != FRAMESETSTATUS_UNASSIGNED || distrenjob_ptr->frameset[1].status != FRAMESETSTATUS_UNASSIGNED)

      /* iterate through all frames for this job: */

      for(counter = 0; counter < distrenjob_ptr->total_frames; counter ++)

	    /*watchdog_forgiveness = seconds of forgiveness before frame is re-assigned: */

        if((distrenjob_ptr->frameset[counter].start_time + distrenjob_ptr->watchdog_forgiveness) < clock())

        {

            /*

            If frame is not completed within the number of seconds specified by watchdog_forgiveness

            Then change the frame status to unassigned

            */

            distrenjob_ptr->frameset[counter].status = FRAMESETSTATUS_UNASSIGNED;

            distrenjob_ptr->assigned_frames--;

        }

    updateJobStatsXML(distrenjob_ptr);

  }

}

/**

   Finds a distrenjob struct based on the jobnum

   @arg jobnum job number to search for

   @return NULL on job doesn't exist

 */

struct distrenjob *distrenjob_get(struct distrenjob *head, jobnum_t jobnum)

{

  struct distrenjob *distrenjob_ptr;

  /*

    The conditions of the for loop will leave distrenjob_ptr at NULL if the end of the list is reached. It will leave it pointing to the correct job if it is found.

   */

  for(distrenjob_ptr = head;

      distrenjob_ptr

        && distrenjob_ptr->jobnum != jobnum;

      distrenjob_ptr = distrenjob_ptr->next);

  return distrenjob_ptr;

}

/**

   Removes a distrenjob from the distrenjob linked list. It does not free the distrenjob, however. You should do that with distrenjob_free() from distrenjob.h

   @arg head pointer to the head of the linkedlist of distrenjobs

 */

void distrenjob_remove(struct general_info *geninfo, struct distrenjob *bj)

{

  struct distrenjob *previous_distrenjob;

  for(previous_distrenjob = &geninfo->head;

      previous_distrenjob

	&& previous_distrenjob->next != bj; /*< stop on the distrenjob that comes before bj */

      previous_distrenjob = previous_distrenjob->next)

    ;

  /*

    This removes references to bj from the linked list. I.E., we now skip bj when iterating through the list

  */

  previous_distrenjob->next = bj->next;

  geninfo->jobs_in_queue --;

}

/* Grabs config info from confs */

int distrend_do_config(int argc, char *argv[], struct distrend_config **config)

{

  unsigned int counter;

  cfg_opt_t myopts_listen[] =

    {

      CFG_SIMPLE_STR("type", NULL),

      CFG_SIMPLE_STR("path", NULL),

      CFG_SIMPLE_INT("port", NULL),

      CFG_END()

    };

  cfg_opt_t myopts[] =

    {

      CFG_SEC("listen",  /* this must be imported into struct listens (which must still be declared) */

          myopts_listen,

          CFGF_MULTI),

      CFG_SIMPLE_STR("datadir", NULL),

      CFG_END()

    };

  struct distrenjob *distrenjob;

  cfg_t *cfg_listen;

  int tmp;

  /*

   * test xml2distrenjob()

   */

  tmp = xml2distrenjob(&distrenjob, "distrenjob.xml.example");

  if(tmp)

    fprintf(stderr, "xml2distrenjob() returned %d. Try to cd to distren/doc if you want to test out the xml2distrenjob() function. (This will only fix this error if the error is due to an inability of the xml library to access distrenjob.xml.example)\n\n", tmp);

  else

    fprintf(stderr, "using email ``%s'' for user ``%s'' -- reading in XML files and pulling data from them using libxml2+XPath works!!!\n", distrenjob->email, distrenjob->submitter);

  fprintf(stderr, "%s:%d running config\n", __FILE__, __LINE__);

  *config = malloc(sizeof(struct distrend_config));

  myopts[1].simple_value = &(*config)->datadir;

  if(options_init(argc, argv, &(*config)->mycfg, myopts, "daemon", &(*config)->options))

    return 1;

  /**

     grab listen blocks:

   */

  (*config)->listens = malloc(sizeof(struct distrend_listen) * (cfg_size((*config)->mycfg, "listen") + 1));

  for(counter = 0; counter < cfg_size((*config)->mycfg, "listen"); counter ++)

    {

      cfg_listen = cfg_getnsec((*config)->mycfg, "listen", counter);

      (*config)->listens[counter].port = cfg_getint(cfg_listen, "port");

      (*config)->listens[counter].sock = -1;

    }

  memset(&(*config)->listens[counter], '\0', sizeof(struct distrend_listen));

  fprintf(stderr, "using %s as datadir\n", (*config)->datadir);

  return 0;

}

int distrend_config_free(struct distrend_config *config)

{

  options_free(config->options);

  free(config);

  return 0;

}

/* ************************** XML Functions ************************* */

// writes the general_info.xml file which is a copy of the general_info structure

// except that it doesn't hold free_clients and rendering_clients

void update_general_info(struct general_info *geninfo)

{

  xmlTextWriterPtr writer;

  char *tmp;

  writer = xmlNewTextWriterFilename("general_info.xml", 0);

  xmlTextWriterStartDocument(writer, NULL, "utf-8", NULL);

  xmlTextWriterStartElement(writer, (xmlChar*)"general_info");

  _distren_asprintf(&tmp, "%d", geninfo->jobs_in_queue);

  xmlTextWriterWriteElement(writer, (xmlChar*)"jobs_in_queue", (xmlChar*)tmp);

  _distren_asprintf(&tmp, "%d", geninfo->total_finished_jobs);

  xmlTextWriterWriteElement(writer, (xmlChar*)"total_finished_jobs", (xmlChar*)tmp);

  _distren_asprintf(&tmp, "%d", geninfo->total_frames_rendered);

  xmlTextWriterWriteElement(writer, (xmlChar*)"total_frames_rendered", (xmlChar*)tmp);

  _distren_asprintf(&tmp, "%d", geninfo->highest_jobnum);

  xmlTextWriterWriteElement(writer, (xmlChar*)"highest_jobnum", (xmlChar*)tmp);

  xmlTextWriterEndDocument(writer);

  xmlFreeTextWriter(writer);

}

// this reads the information from general_info.xml to the general_info structure

int import_general_info(struct general_info *general_info)

{

  xmlDocPtr doc;

  xmlNodePtr cur;

  doc = xmlParseFile("general_info.xml");

  cur = xmlDocGetRootElement(doc);

  if (xmlStrcmp(cur->name, (xmlChar*)"general_info"))

    {

      fprintf(stderr, "xml document is wrong type");

      xmlFreeDoc(doc);

      return 1;

    }

  cur = cur->xmlChildrenNode;

  general_info->jobs_in_queue = atoi((char*)xmlNodeListGetString(doc, cur->xmlChildrenNode, 1));

  cur = cur->next;

  general_info->total_finished_jobs = atoi((char*)xmlNodeListGetString(doc, cur->xmlChildrenNode, 1));

  cur = cur->next;

  general_info->total_frames_rendered = atoi((char*)xmlNodeListGetString(doc, cur->xmlChildrenNode, 1));

  cur = cur->next;

  general_info->highest_jobnum = atoi((char*)xmlNodeListGetString(doc, cur->xmlChildrenNode, 1));

  general_info->hibernate = 0;

  general_info->free_clients = 0;

  general_info->rendering_clients = 0;

  general_info->timestamp = 0;

  general_info->total_render_power = 0;

  general_info->total_priority_pieces = 0;

  xmlFreeDoc(doc);

  return 0;

}

{

  xmlTextWriterPtr writer;

  xmlTextWriterStartDocument(writer, NULL, "utf-8", NULL);

  xmlTextWriterStartElement(writer, (xmlChar*)"job");

  xmlTextWriterWriteAttribute(writer, (xmlChar*)"name", (xmlChar*)job->name);

  xmlTextWriterWriteAttribute(writer, (xmlChar*)"submitter", (xmlChar*)job->submitter);

  _distren_asprintf(&tmp, "%d", job->priority);

  xmlTextWriterWriteAttribute(writer, (xmlChar*)"priority", (xmlChar*)tmp);

  xmlTextWriterStartElement(writer, (xmlChar*)"resolution");

  _distren_asprintf(&tmp, "%d", job->width);

  xmlTextWriterWriteAttribute(writer, (xmlChar*)"width", (xmlChar*)tmp);

  _distren_asprintf(&tmp, "%d", job->height);

  xmlTextWriterWriteAttribute(writer, (xmlChar*)"height", (xmlChar*)tmp);

  xmlTextWriterEndElement(writer);

  xmlTextWriterStartElement(writer, (xmlChar*)"video");

  _distren_asprintf(&tmp, "%d", job->frameset[0].num);

  xmlTextWriterWriteAttribute(writer, (xmlChar*)"start_frame", (xmlChar*)tmp);

  _distren_asprintf(&tmp, "%d", job->frameset[(job->total_frames - 1)].num);

  xmlTextWriterWriteAttribute(writer, (xmlChar*)"end_fame", (xmlChar*)tmp);

  xmlTextWriterWriteAttribute(writer, (xmlChar*)"output_format", (xmlChar*)job->output_format);

  xmlTextWriterEndElement(writer);

  _distren_asprintf(&tmp, "%d", job->watchdog_forgiveness);

  xmlTextWriterWriteElement(writer, (xmlChar*)"wd_forgiveness", (xmlChar*)tmp);

  xmlTextWriterEndDocument(writer);

  xmlFreeTextWriter(writer);

}

// extracts data from the xml created by above function and creates a job from it

// it returns a pointer to the created job

struct distrenjob *createJobFromXML(int job_number)

{

  xmlDocPtr doc;

  xmlNodePtr cur;

  char *file_name;

  struct distrenjob *distrenjob;

  int start_frame;

  int counter;

  int counter2;

  _distren_asprintf(&file_name, "stor/job%d/job_info.xml", job_number);

  doc = xmlParseFile(file_name);

  if(!doc)

    return NULL;

  distrenjob_new(&distrenjob);

  cur = xmlDocGetRootElement(doc);

  distrenjob->name = (char*)xmlGetProp(cur, (xmlChar*)"name");

  distrenjob->submitter = (char*)xmlGetProp(cur, (xmlChar*)"submitter");

  distrenjob->priority = atoi((char*)xmlGetProp(cur, (xmlChar*)"priority"));

  cur = cur->xmlChildrenNode;

  distrenjob->width = atoi((char*)xmlGetProp(cur, (xmlChar*)"width"));

  distrenjob->height = atoi((char*)xmlGetProp(cur, (xmlChar*)"number"));

  cur = cur->next;