class date_views_plugin_pager

date_autoload_info in core/modules/date/date.module

Implements hook_autoload_info().

date_views_plugins in core/modules/date/views/date.views.inc

Implements hook_views_plugins().

class date_views_plugin_pager extends views_plugin_pager {

  /**
   * This kind of pager does not need to count the number of records.
   */
  public function use_count_query() {
    return FALSE;
  }

  /**
   * Set a default value.
   *
   * Because we don't know how many pages there are, we never believe
   * there are more records.
   */
  public function has_more_records() {
    return FALSE;
  }

  /**
   * Tell Views what this pager's setting is.
   */
  public function summary_title() {
    return t("Position: @position, format: @format.", array('@position' => $this->options['pager_position'], '@format' => $this->options['link_format']));
  }

  /**
   * Tell Views what options this plugin can store.
   */
  public function option_definition() {
    $options = parent::option_definition();
    $options['date_id'] = array('default' => 'date');
    $options['pager_position'] = array('default' => 'top');
    $options['link_format'] = array('default' => 'pager');
    $options['date_argument'] = array('default' => 'Unknown');
    $options['granularity'] = array('default' => 'Unknown');
    $options['skip_empty_pages'] = array('default' => FALSE);
    return $options;
  }

  /**
   * Provide the form for setting options.
   */
  public function options_form(&$form, &$form_state) {
    $form['markup']['#markup'] = t('This pager works together with a Date or Content date field contextual filter. If a Date filter has been added to the view, this pager will provide back/next paging to match the granularity of that filter (i.e. paging by year, month, week, or day). The filter must also be configured to use a DATE default value. If there is no Date contextual filter on this view, or if it has not been set to use a default date, the pager will not appear.');
    $form['date_id'] = array(
      '#title' => t('Date identifier'),
      '#type' => 'textfield',
      '#description' => t('The query identifier to use when fetching date data from in the URL. Note that if you have more than one display in the same view that uses the date pager (like a page and a block), the pager id must be different for each one or both will change when the pager value changes.'),
      '#default_value' => $this->options['date_id'],
      '#required' => TRUE,
    );
    $form['pager_position'] = array(
      '#title' => t('Pager position'),
      '#type' => 'select',
      '#options' => array(
        'bottom' => t('Bottom'),
        'top' => t('Top'),
        'both' => t('Both'),
      ),
      '#description' => t('Where to place the date pager, on the top, bottom, or both top and bottom of the content.'),
      '#default_value' => $this->options['pager_position'],
      '#required' => TRUE,
    );
    $form['link_format'] = array(
      '#title' => t('Link format'),
      '#type' => 'select',
      '#options' => array('pager' => t('Pager'), 'clean' => t('Clean URL')),
      '#description' => t("The format for pager link urls. With the Pager format, the links look like 'calendar/?date=2020-05'. The Clean URL format links look like 'calendar/2020-05'. The Clean format links look nicer but the Pager format links are likely to work better if the calendar is used in blocks or panels."),
      '#default_value' => $this->options['link_format'],
      '#required' => TRUE,
    );
    $form['skip_empty_pages'] = array(
      '#title' => t('Skip empty pages'),
      '#type' => 'checkbox',
      '#description' => t('When selected, the pager will not display pages with no result for the given date. This causes a slight performance degradation because two additional queries need to be executed.'),
      '#default_value' => $this->options['skip_empty_pages'],
    );
    $form['date_argument']['#type'] = 'hidden';
    $form['date_argument']['#value'] = $this->options['date_argument'];
    $form['granularity']['#type'] = 'hidden';
    $form['granularity']['#value'] = $this->options['granularity'];
  }

  /**
   * Transfer date information from the argument to the view.
   *
   * The pager theme can use it and update the date argument value
   * to whatever is set by the pager.
   */
  public function query() {

    // By fetching our data from the exposed input, it is possible to
    // feed pager data through some method other than $_GET.
    $input = $this->view->get_exposed_input();
    $value = NULL;
    if (!empty($input) && !empty($input[$this->options['date_id']])) {
      $value = $input[$this->options['date_id']];
    }

    // Bring the argument information into the view so our theme can access it.
    $i = 0;
    foreach ($this->view->argument as $id => &$argument) {
      if (date_views_handler_is_date($argument, 'argument')) {

        // If the argument is empty, nothing to do. This could be from
        // an argument that does not set a default value.
        if (empty($argument->argument) || empty($argument->date_handler)) {
          continue;
        }

        // Storing this information in the pager so it's available
        // for summary info.
        // The view argument information is not otherwise accessible
        // to the pager. Not working right yet, tho.
        $date_handler = $argument->date_handler;
        $this->options['date_argument'] = $id;
        $this->options['granularity'] = $argument->date_handler->granularity;

        // Reset values set by argument if pager requires it.
        if (!empty($value)) {
          $this->set_argument_value($argument, $value);
        }

        // The pager value might move us into a forbidden range, so test it.
        if ($this->date_forbid($argument)) {
          $this->view->build_info['fail'] = TRUE;
          return;
        }
        // Write date_info to store information to be used
        // in the theming functions.
        if (empty($this->view->date_info)) {
          $this->view->date_info = new stdClass();
        }
        $this->view->date_info->granularity = $argument->date_handler->granularity;
        $format = $this->view->date_info->granularity == 'week' ? DATE_FORMAT_DATETIME : $argument->sql_format;
        $this->view->date_info->placeholders = isset($argument->placeholders) ? $argument->placeholders : $argument->date_handler->placeholders;
        $this->view->date_info->date_arg = $argument->argument;
        $this->view->date_info->date_arg_pos = $i;
        $this->view->date_info->limit = $argument->limit;
        $this->view->date_info->url = $this->view->get_url();
        $this->view->date_info->pager_id = $this->options['date_id'];
        $this->view->date_info->date_pager_position = $this->options['pager_position'];
        $this->view->date_info->date_pager_format = $this->options['link_format'];
        $this->view->date_info->skip_empty_pages = $this->options['skip_empty_pages'] == 1;
        // Execute two additional queries to find
        // the previous and next page with values.
        if ($this->view->date_info->skip_empty_pages) {
          $q = clone $argument->query;
          $field = $argument->table_alias . '.' . $argument->real_field;
          $fieldsql = $date_handler->sql_field($field);
          $fieldsql = $date_handler->sql_format($format, $fieldsql);
          $q->clear_fields();
          $q->orderby = array();
          $q->set_distinct(TRUE, TRUE);
          // Date limits of this argument.
          $datelimits = $argument->date_handler->arg_range($argument->limit[0] . '--' . $argument->limit[1]);
          // Find the first two dates between the minimum date
          // and the upper bound of the current value.
          $q->add_orderby(NULL, $fieldsql, 'DESC', 'date');
          $this->set_argument_placeholders($this->view->date_info->placeholders, $datelimits[0], $argument->max_date, $q, $format);

          $compiledquery = $q->query();
          $compiledquery->range(0, 2);
          $results = $compiledquery->execute()->fetchCol(0);

          $prevdate = array_shift($results);
          $prevdatealt = array_shift($results);
          // Find the first two dates between the lower bound
          // of the current value and the maximum date.
          $q->add_orderby(NULL, $fieldsql, 'ASC', 'date');
          $this->set_argument_placeholders($this->view->date_info->placeholders, $argument->min_date, $datelimits[1], $q, $format);

          $compiledquery = $q->query();
          $compiledquery->range(0, 2);
          $results = $compiledquery->execute()->fetchCol(0);

          $nextdate = array_shift($results);
          $nextdatealt = array_shift($results);

          // Set the default value of the query to $prevfirst or $nextfirst
          // when there is no value and $prevsecond or $nextsecond is set.
          if (empty($value)) {
            // @Todo find out which of $prevdate or $nextdate is closest to the
            // default argument date value and choose that one.
            if ($prevdate && $prevdatealt) {
              $this->set_argument_value($argument, $prevdate);
              $value = $prevdate;
              $prevdate = $prevdatealt;
              // If the first next date is the same as the first previous date,
              // move to the following next date.
              if ($value == $nextdate) {
                $nextdate = $nextdatealt;
                $nextdatealt = NULL;
              }
            }
            elseif ($nextdate && $nextdatealt) {
              $this->set_argument_value($argument, $nextdate);
              $value = $nextdate;
              $nextdate = $nextdatealt;
              // If the first previous date is the same as the first next date,
              // move to the following previous date.
              if ($value == $prevdate) {
                $prevdate = $prevdatealt;
                $prevdatealt = NULL;
              }
            }
          }
          else {
            // $prevdate and $nextdate are the same as $value, so move to
            // the next values.
            $prevdate = $prevdatealt;
            $nextdate = $nextdatealt;
          }

          $this->view->date_info->prev_date = $prevdate ? new BackdropDateTime($prevdate, NULL, $format) : NULL;
          $this->view->date_info->next_date = $nextdate ? new BackdropDateTime($nextdate, NULL, $format) : NULL;
        }
        else {
          $this->view->date_info->prev_date = clone($argument->min_date);
          date_modify($this->view->date_info->prev_date, '-1 ' . $argument->date_handler->granularity);
          $this->view->date_info->next_date = clone($argument->min_date);
          date_modify($this->view->date_info->next_date, '+1 ' . $argument->date_handler->granularity);
        }
        // Write the date_info properties that depend on the current value.
        $this->view->date_info->year = date_format($argument->min_date, 'Y');
        $this->view->date_info->month = date_format($argument->min_date, 'n');
        $this->view->date_info->day = date_format($argument->min_date, 'j');
        $this->view->date_info->week = date_week(date_format($argument->min_date, DATE_FORMAT_DATE));
        $this->view->date_info->date_range = $argument->date_range;
        $this->view->date_info->min_date = $argument->min_date;
        $this->view->date_info->max_date = $argument->max_date;
      }
      $i++;
    }

    // Is this a view that needs to be altered based on a pager value?
    // If there is pager input and the argument has set the placeholders,
    // swap the pager value in for the placeholder set by the argument.
    if (!empty($value) && !empty($this->view->date_info->placeholders)) {
      $this->set_argument_placeholders($this->view->date_info->placeholders, $this->view->date_info->min_date, $this->view->date_info->max_date, $this->view->query, $format);
    }
  }

  /**
   * Set the view's argument value.
   */
  public function set_argument_value($argument, $value) {
    $argument->argument = $value;
    $argument->date_range = $argument->date_handler->arg_range($value);
    $argument->min_date = $argument->date_range[0];
    $argument->max_date = $argument->date_range[1];
    // $argument->is_default works correctly for normal arguments, but does not
    // work correctly if we are swapping in a new value from the pager.
    $argument->is_default = FALSE;
  }

  /**
   * Set the view's argument placeholders.
   */
  public function set_argument_placeholders($placeholders, $mindate, $maxdate, $query, $format) {
    $count = count($placeholders);
    foreach ($query->where as $group => $data) {
      foreach ($data['conditions'] as $delta => $condition) {
        if (array_key_exists('value', $condition) && is_array($condition['value'])) {
          foreach ($condition['value'] as $placeholder => $placeholder_value) {
            if (array_key_exists($placeholder, $placeholders)) {
              // If we didn't get a match, this is a > $min < $max query
              // that uses the view min and max dates as placeholders.
              $date = ($count == 2) ? $mindate : $maxdate;
              $next_placeholder = array_shift($placeholders);
              $query->where[$group]['conditions'][$delta]['value'][$placeholder] = $date->format($format);
              $count--;
            }
          }
        }
      }
    }
  }

  /**
   * Custom callback evaluating the date range.
   *
   * Add a callback to determine if we have moved outside the valid date range
   * for this views argument.
   */
  public function date_forbid($argument) {
    // See if we're outside the allowed date range for our argument.
    $limit = date_range_years($argument->options['year_range']);
    if (date_format($argument->min_date, 'Y') < $limit[0] || date_format($argument->max_date, 'Y') > $limit[1]) {
      return TRUE;
    }
    return FALSE;
  }

  /**
   * Render the pager.
   */
  public function render($input) {
    // This adds all of our template suggestions based upon the view name
    // and display id.
    $pager_theme = views_theme_functions('date_views_pager', $this->view, $this->display);
    return theme($pager_theme, array('plugin' => $this, 'input' => $input));
  }

}