/*

  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/encoding.h>

#include <libxml/parser.h>

#include <libxml/tree.h>

#include <libxml/xmlmemory.h>

#include <libxml/xmlreader.h>

#include <libxml/xmlwriter.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 general_info*);

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

void update_general_info(struct general_info*);

int import_general_info(struct general_info*);

int updateJobStatsXML(struct distrenjob *job);

char *job_getserialfilename(struct general_info *, unsigned int jobnum);

/* ********************** 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! @TODO: Fill this stub*/

int xml_dump()

{

  return 0;

}

/**

   Performs command stored in a client's request. @TODO: Fill stub

*/

int distrend_do()

{

  return 0;

}

/** 

    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))

	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;

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

    {

      _distren_asprintf(&path_and_number, "%s/stor/job%d/out/%d.%s",

			geninfo->config->datadir,

			job->jobnum,

			job->frameset[counter].num,

			job->output_format);

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

        {

	  /**

	     missing frame found

	   */

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

          job->completed_frames--;

          geninfo->total_frames_rendered--;

          isJobDone = 0;

        }

      free(path_and_number);

    }

  if(isJobDone)

    {

      /**

	 all frames were accounted for

      */

      distrenjob_remove(geninfo, job);

      distrenjob_free(&job);

      geninfo->jobs_in_queue --;

      update_xml_joblist(geninfo);

    }

  else

    /**

       if the job isn't done, have frame_finder() start from the first frame, allowing it to see the frames that are now unassigned 

    */

    job->prev_frame_index = -1;

  update_general_info(geninfo);

  return 0;

}

/**

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

   @return 0 if the job is completely done and there are no missing frames,

           1 if missing frames are 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); /*< @TODO this path is used in multiple places, construct/build/determine it in a central function */

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

        {

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

          job->completed_frames++;

        }

      else

        isJobDone = 0;

      free(path_and_number);

    }

  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 tmp;

  char *path_with_num;

  char *serialfile;

  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;

  /** sets the total number of frames in animation for status purposes */

  distrenjob->total_frames = (end_frame - start_frame + 1);

  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, ">>NOT<< creating dir ``%s''\n", path_with_num); /*< @TODO recursively create job directory */

  serialfile = job_getserialfilename(geninfo, distrenjob->jobnum);

  free(path_with_num);

  /**

     add job to queue

  */

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

  distrenjob_serialize(distrenjob, serialfile);

  free(serialfile);

  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 jobs

  */

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

  {

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

    if(job->priority < current_job->priority)

      {

	/**

	   if job's priority is less than current_job's priority, insert job

	   keep in mind 1 is the highest priority given to jobs, head has a

	   priority of zero so it will always be before other jobs

	*/

	prev_job->next = job;

	job->next = current_job;

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

	return 0;

      }

    prev_job = current_job;

  }

  /**

     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");

  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){

  struct distrenjob *current_job;

  struct distrenjob *prev_job;

  char *serialname;

  distrenjob_remove(geninfo, job);

  job->priority = new_priority;

  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);

  /** reserialize after changes */

  serialname = job_getserialfilename(geninfo, job->jobnum);

  distrenjob_serialize(job, serialname);

  free(serialname);

  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_STR_LIST("render_types", NULL, CFGF_NONE),

      CFG_END()

    };

  struct distrenjob *distrenjob;

  cfg_t *cfg_listen;

  int tmp;

  *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);

  free(tmp);

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

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

  free(tmp);

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

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

  free(tmp);

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

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

  free(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;

}

// 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(struct general_info *geninfo, unsigned int jobnum)

{

  xmlDocPtr doc;

  xmlNodePtr cur;

  char *file_name;

  struct distrenjob *distrenjob;

  int start_frame;

  int counter;

  int counter2;

  file_name = job_getserialfilename(geninfo, jobnum);

  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;

  start_frame = atoi((char*)xmlGetProp(cur, (xmlChar*)"start_frame"));

  distrenjob->total_frames = atoi((char*)xmlGetProp(cur, (xmlChar*)"end_frame")) - start_frame + 1;

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

  cur = cur->next;

  distrenjob->watchdog_forgiveness = atoi((char*)xmlNodeListGetString(doc, cur->xmlChildrenNode, 1));

  xmlFreeDoc(doc);

  /** load up stats.xml file to retrieve data */

  _distren_asprintf(&file_name, "stor/job%d/stats.xml", jobnum);

  doc = xmlParseFile(file_name);

  free(file_name);

  cur = xmlDocGetRootElement(doc);

  distrenjob->total_render_time = (time_t)atol((char*)xmlGetProp(cur, (xmlChar*)"total_render_time"));

  xmlFreeDoc(doc);

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

  // change the status of all frames 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++;

  }

  restoreJobState(distrenjob);

  return distrenjob;

}

int updateJobStatsXML(struct distrenjob *job)

{

	  xmlTextWriterPtr writer;

	  char *tmp;

	  _distren_asprintf(&tmp, "stor/job%d/stats.xml", job->jobnum);

	  /**

	     create xml document at the location tmp with no compression

	  */

	  writer = xmlNewTextWriterFilename(tmp, 0);

	  free(tmp);

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