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root / drupal7 / sites / all / modules / job_scheduler / JobScheduler.inc @ 082b75eb

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<?php
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/**
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 * @file
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 * JobScheduler class.
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 */
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/**
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 * Use to make Job Scheduler exceptions identifiable by type.
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 */
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class JobSchedulerException extends Exception {}
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/**
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 * Manage scheduled jobs.
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 */
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class JobScheduler {
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  /**
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   * The name of this scheduler.
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   *
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   * @var string
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   */
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  protected $name;
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  /**
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   * Produces a single instance of JobScheduler for a schedule name.
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   */
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  public static function get($name) {
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    static $schedulers;
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    // Instantiante a new scheduler for $name if we haven't done so yet.
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    if (!isset($schedulers[$name])) {
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      $class = variable_get('job_scheduler_class_' . $name, 'JobScheduler');
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      $schedulers[$name] = new $class($name);
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    }
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    return $schedulers[$name];
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  }
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  /**
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   * Creates a JobScheduler object.
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   */
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  protected function __construct($name) {
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    $this->name = $name;
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  }
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  /**
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   * Returns scheduler info.
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   *
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   * @see hook_cron_job_scheduler_info()
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   *
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   * @throws JobSchedulerException.
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   */
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  public function info() {
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    if ($info = job_scheduler_info($this->name)) {
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      return $info;
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    }
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    throw new JobSchedulerException('Could not find Job Scheduler cron information for ' . check_plain($this->name));
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  }
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  /**
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   * Add a job to the schedule, replace any existing job.
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   *
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   * A job is uniquely identified by $job = array(type, id).
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   *
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   * @param array $job
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   *   An array that must contain the following keys:
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   *   'type'     - A string identifier of the type of job.
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   *   'id'       - A numeric identifier of the job.
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   *   'periodic' - True if the task should be repeated periodically.
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   *
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   *   The array must also contain one of the following keys:
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   *   'period'  - The time when the task should be executed.
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   *   'crontab' - A crontab entry which describes the times a task should be
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   *               executed.
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   *
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   * @code
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   * function worker_callback($job) {
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   *   // Work off job.
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   *   // Set next time to be called. If this portion of the code is not
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   *   // reached for some reason, the scheduler will keep periodically invoking
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   *   // the callback() with the period value initially specified.
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   *   $scheduler->set($job);
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   * }
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   * @endcode
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   *
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   * @codingStandardsIgnoreStart
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   */
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  public function set($job) {
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    // @codingStandardsIgnoreEnd
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    $job['name'] = $this->name;
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    $job['last'] = REQUEST_TIME;
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    if (!empty($job['crontab'])) {
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      $crontab = new JobSchedulerCronTab($job['crontab']);
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      $job['next'] = $crontab->nextTime(REQUEST_TIME);
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    }
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    else {
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      $job['next'] = REQUEST_TIME + $job['period'];
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    }
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    $job['scheduled'] = 0;
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    $this->remove($job);
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    drupal_write_record('job_schedule', $job);
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  }
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  /**
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   * Reserve a job.
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   */
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  protected function reserve($job) {
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    $job['name'] = $this->name;
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    $job['scheduled'] =
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    $job['last'] = REQUEST_TIME;
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    $job['next'] = $job['period'] + REQUEST_TIME;
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    drupal_write_record('job_schedule', $job, array('name', 'type', 'id'));
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  }
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  /**
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   * Remove a job from the schedule, replace any existing job.
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   *
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   * A job is uniquely identified by $job = array(type, id).
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   */
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  public function remove($job) {
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    db_delete('job_schedule')
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      ->condition('name', $this->name)
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      ->condition('type', $job['type'])
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      ->condition('id', isset($job['id']) ? $job['id'] : 0)
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      ->execute();
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  }
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  /**
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   * Remove all jobs for a given type.
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   */
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  public function removeAll($type) {
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    db_delete('job_schedule')
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      ->condition('name', $this->name)
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      ->condition('type', $type)
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      ->execute();
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  }
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  /**
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   * Dispatches a job.
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   *
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   * Executes a worker callback or if schedule declares a queue name, queues a
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   * job for execution.
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   *
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   * @param array $job
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   *   A $job array as passed into set() or read from job_schedule table.
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   *
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   * @throws Exception
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   *   Exceptions thrown by code called by this method are passed on.
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   *
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   * @codingStandardsIgnoreStart
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   */
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  public function dispatch($job) {
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    // @codingStandardsIgnoreEnd
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    $info = $this->info();
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    if (!$job['periodic']) {
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      $this->remove($job);
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    }
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    if (!empty($info['queue name'])) {
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      if (DrupalQueue::get($info['queue name'])->createItem($job)) {
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        $this->reserve($job);
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      }
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    }
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    else {
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      $this->execute($job);
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    }
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  }
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  /**
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   * Executes a job that.
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   *
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   * @param array $job
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   *   A $job array as passed into set() or read from job_schedule table.
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   *
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   * @throws Exception
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   *   Exceptions thrown by code called by this method are passed on.
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   *
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   * @codingStandardsIgnoreStart
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   */
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  public function execute($job) {
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    // @codingStandardsIgnoreEnd
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    $info = $this->info();
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    // If the job is periodic, re-schedule it before calling the worker, just in
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    // case.
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    if ($job['periodic']) {
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      $job['last'] = REQUEST_TIME;
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      $this->reschedule($job);
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    }
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    if (!empty($info['file']) && file_exists($info['file'])) {
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      include_once $info['file'];
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    }
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    if (function_exists($info['worker callback'])) {
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      call_user_func($info['worker callback'], $job);
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    }
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    else {
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      // @todo If worker doesn't exist anymore we should do something about it, remove and throw exception?
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      $this->remove($job);
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      throw new JobSchedulerException('Could not find worker callback function: ' . $info['worker callback']);
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    }
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  }
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  /**
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   * Re-schedule a job if intended to run again.
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   *
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   * (If cannot determine the next time, drop the job)
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   */
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  public function reschedule($job) {
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    $job['scheduled'] = 0;
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    if (!empty($job['crontab'])) {
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      $crontab = new JobSchedulerCronTab($job['crontab']);
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      $job['next'] = $crontab->nextTime($job['last']);
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    }
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    else {
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      $job['next'] = $job['last'] + $job['period'];
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    }
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    if ($job['next']) {
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      drupal_write_record('job_schedule', $job, array('item_id'));
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    }
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    else {
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      // If no next time, it may mean it won't run again the next year (crontab)
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      $this->remove($job);
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    }
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  }
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  /**
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   * Check whether a job exists in the queue and update its parameters if so.
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   */
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  public function check($job) {
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    $job += array('id' => 0, 'period' => 0, 'crontab' => '');
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    $existing = db_select('job_schedule')
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      ->fields('job_schedule')
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      ->condition('name', $this->name)
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      ->condition('type', $job['type'])
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      ->condition('id', $job['id'])
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      ->execute()
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      ->fetchAssoc();
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    // If existing, and changed period or crontab, we need to reschedule the
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    // job.
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    if ($existing) {
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      if ($job['period'] != $existing['period'] || $job['crontab'] != $existing['crontab']) {
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        $existing['period'] = $job['period'];
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        $existing['crontab'] = $job['crontab'];
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        $this->reschedule($existing);
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      }
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      return $existing;
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    }
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  }
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}