prev_next.module in Previous/Next API 6

Same filename and directory in other branches
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prev_next.module
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<?php

define('PREV_NEXT_BATCH_SIZE_DEFAULT', 200);
define('PREV_NEXT_INDEXING_CRITERIA_DEFAULT', 'nid');
define('PREV_NEXT_NODE_TYPE', 'prev_next_node_type_');
define('PREV_NEXT_NUM_BLOCKS_DEFAULT', 1);
define('PREV_NEXT_DISPLAY_DEFAULT', 1);
define('PREV_NEXT_DISPLAY_TEXT_PREV_DEFAULT', '[title] »');
define('PREV_NEXT_DISPLAY_TEXT_NEXT_DEFAULT', '« [title]');

/**
 * Implementation of hook_menu().
 */
function prev_next_menu() {
  $items['admin/settings/prev_next'] = array(
    'title' => 'Prev/Next',
    'description' => 'Prev/Next API for nodes',
    'page callback' => 'drupal_get_form',
    'page arguments' => array(
      'prev_next_admin',
    ),
    'access arguments' => array(
      'access administration pages',
    ),
  );
  $items['admin/settings/prev_next/general'] = array(
    'title' => 'General',
    'weight' => 0,
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['admin/settings/prev_next/re-index'] = array(
    'type' => MENU_CALLBACK,
    'title' => 'Prev/Next reset',
    'page callback' => 'drupal_get_form',
    'page arguments' => array(
      'prev_next_reindex_confirm',
    ),
    'access arguments' => array(
      'access administration pages',
    ),
  );
  return $items;
}

/**
 * Menu callback argument. Creates the prev_next administration form.
 */
function prev_next_admin() {
  $form['status'] = array(
    '#type' => 'fieldset',
    '#title' => t('Indexing status'),
  );
  $max_nid = variable_get('prev_next_index_nid', 0);
  $cond = _prev_next_node_types_sql();
  $total = db_result(db_query("SELECT COUNT(nid) FROM {node} WHERE status = 1 {$cond}"));
  $completed = db_result(db_query("SELECT COUNT(nid) FROM {prev_next_node}"));
  $remaining = max(0, $total - $completed);
  $percentage = (int) min(100, 100 * ($total - $remaining) / max(1, $total)) . '%';
  $status = t('<p>%percentage of nodes have been indexed. There are %remaining items left to index, out of a total of %total.</p>', array(
    '%percentage' => $percentage,
    '%remaining' => $remaining,
    '%total' => $total,
  ));
  $status .= $max_nid ? t('<p>Max node ID for indexing on the next cron run: @max.</p>', array(
    '@max' => $max_nid,
  )) : t('<p>Existing nodes have finished prev/next indexing.</p>');
  $form['status']['status'] = array(
    '#value' => $status,
  );
  $form['status']['reindex'] = array(
    '#type' => 'submit',
    '#value' => t('Re-index'),
  );
  $form['prev_next_batch_size'] = array(
    '#title' => t('Batch size'),
    '#description' => t('Number of nodes to index during each cron run.'),
    '#type' => 'textfield',
    '#size' => 6,
    '#maxlength' => 7,
    '#default_value' => variable_get('prev_next_batch_size', PREV_NEXT_BATCH_SIZE_DEFAULT),
    '#required' => TRUE,
  );
  $form['prev_next_num_blocks'] = array(
    '#title' => t('Blocks'),
    '#description' => t('Number of blocks available.'),
    '#type' => 'textfield',
    '#size' => 2,
    '#maxlength' => 3,
    '#default_value' => variable_get('prev_next_num_blocks', PREV_NEXT_NUM_BLOCKS_DEFAULT),
    '#required' => TRUE,
  );
  $form['node_types'] = array(
    '#type' => 'fieldset',
    '#title' => t('Content types'),
    '#description' => t('Define settings for each content type. If none of them is included, then all of them will be.'),
  );
  foreach (node_get_types() as $type => $name) {
    $form['node_types'][$type] = array(
      '#type' => 'fieldset',
      '#description' => t('Note: changing one of these values will reset the entire Prev/Next index.'),
      '#title' => node_get_types('name', $type),
      '#collapsible' => TRUE,
      '#collapsed' => !variable_get(PREV_NEXT_NODE_TYPE . $type, 0),
    );
    $form['node_types'][$type][PREV_NEXT_NODE_TYPE . $type] = array(
      '#type' => 'checkbox',
      '#title' => t('Include'),
      '#default_value' => variable_get(PREV_NEXT_NODE_TYPE . $type, 0),
    );
    $form['node_types'][$type][PREV_NEXT_NODE_TYPE . $type . '_current'] = array(
      '#type' => 'hidden',
      '#default_value' => variable_get(PREV_NEXT_NODE_TYPE . $type, 0),
    );
    $form['node_types'][$type][PREV_NEXT_NODE_TYPE . $type . '_indexing_criteria'] = array(
      '#title' => t('Indexing criteria'),
      '#type' => 'select',
      '#options' => array(
        'nid' => t('Node ID'),
        'created' => t('Post date'),
        'changed' => t('Updated date'),
        'title' => t('Title'),
      ),
      '#default_value' => variable_get(PREV_NEXT_NODE_TYPE . $type . '_indexing_criteria', PREV_NEXT_INDEXING_CRITERIA_DEFAULT),
    );
    $form['node_types'][$type][PREV_NEXT_NODE_TYPE . $type . '_indexing_criteria_current'] = array(
      '#type' => 'hidden',
      '#value' => variable_get(PREV_NEXT_NODE_TYPE . $type . '_indexing_criteria', PREV_NEXT_INDEXING_CRITERIA_DEFAULT),
    );
    $form['node_types'][$type][PREV_NEXT_NODE_TYPE . $type . '_same_type'] = array(
      '#type' => 'checkbox',
      '#title' => t('Only nodes with same content type'),
      '#default_value' => variable_get(PREV_NEXT_NODE_TYPE . $type . '_same_type', 0),
    );
    $form['node_types'][$type][PREV_NEXT_NODE_TYPE . $type . '_same_type_current'] = array(
      '#type' => 'hidden',
      '#default_value' => variable_get(PREV_NEXT_NODE_TYPE . $type . '_same_type', 0),
    );
  }
  $form['#submit'][] = 'prev_next_admin_submit';
  return system_settings_form($form);
}

/**
 * Validate callback.
 */
function prev_next_admin_validate($form, &$form_state) {
  if ($form_state['values']['op'] == t('Re-index')) {
    drupal_goto('admin/settings/prev_next/re-index');
  }

  // Max_nid is just a markup field and should not cause a variable to be set.
  unset($form_state['values']['max_nid']);

  // The variables must be non-negative and numeric.
  if (!is_numeric($form_state['values']['prev_next_batch_size']) || $form_state['values']['prev_next_batch_size'] <= 0) {
    form_set_error('prev_next_batch_size', t('The batch size must be a number and greater than zero.'));
  }
}

/**
 * Submit callback.
 */
function prev_next_admin_submit($form, &$form_state) {
  $rebuild = FALSE;

  // Test sensitive values.
  foreach (node_get_types() as $type => $name) {
    if ($form_state['values'][PREV_NEXT_NODE_TYPE . $type . '_current'] != $form_state['values'][PREV_NEXT_NODE_TYPE . $type] || $form_state['values'][PREV_NEXT_NODE_TYPE . $type . '_indexing_criteria_current'] != $form_state['values'][PREV_NEXT_NODE_TYPE . $type . '_indexing_criteria'] || $form_state['values'][PREV_NEXT_NODE_TYPE . $type . '_same_type_current'] != $form_state['values'][PREV_NEXT_NODE_TYPE . $type . '_same_type']) {
      $rebuild = TRUE;
    }
  }

  // If the search criterias has been changed, re-index.
  if ($rebuild) {
    prev_next_reindex();
    drupal_set_message(t('The Prev/Next index will be rebuilt.'));
  }
  $form_state['redirect'] = 'admin/settings/prev_next';
}
function prev_next_reindex_confirm() {
  return confirm_form(array(), t('Are you sure you want to re-index Prev/Next?'), 'admin/settings/prev_next', t('The entire Prev/Next index will be reset and rebuilt incrementally as cron runs. action cannot be undone.'), t('Re-index'), t('Cancel'));
}
function prev_next_reindex_confirm_submit(&$form, &$form_state) {
  if ($form['confirm']) {
    prev_next_reindex();
    drupal_set_message(t('The Prev/Next index will be rebuilt.'));
    $form_state['redirect'] = 'admin/settings/prev_next';
  }
}
function prev_next_reindex() {

  // Wipe the table clean
  db_query('TRUNCATE {prev_next_node}');

  // Get the highest nid
  $max_nid = db_result(db_query('SELECT MAX(nid) FROM {node}'));

  // Set the variable to that
  variable_set('prev_next_index_nid', $max_nid);
  if ($max_nid) {
    drupal_set_message(t('Prev/Next will index from node %nid downward.', array(
      '%nid' => $max_nid,
    )));
  }
}

/**
 * Implementation of hook_cron().
 */
function prev_next_cron() {
  $max_nid = variable_get('prev_next_index_nid', 0);
  if ($max_nid) {
    $batch_size = variable_get('prev_next_batch_size', PREV_NEXT_BATCH_SIZE_DEFAULT);
    $last_nid = FALSE;
    $cond = _prev_next_node_types_sql();
    timer_start('prev_next_cron');
    $result = db_query("SELECT nid FROM {node} WHERE nid <= %d AND status = 1 {$cond} ORDER BY nid DESC LIMIT %d", $max_nid, $batch_size);
    $count = 0;
    while ($row = db_fetch_object($result)) {

      // Remove existing data for this node.
      db_query("DELETE FROM {prev_next_node} WHERE nid = %d", $row->nid);
      _prev_next_add($row->nid);

      // Note that we have indexed at least one node.
      $last_nid = $row->nid;
      $count++;
    }
    $time = timer_read('prev_next_cron');
    if ($last_nid !== FALSE) {

      // Prepare a starting point for the next run.
      variable_set('prev_next_index_nid', $last_nid - 1);
    }
    else {

      // If all nodes have been indexed, set to zero to skip future cron runs.
      variable_set('prev_next_index_nid', 0);
    }
    watchdog('prev_next', 'Indexed %count nodes in %time milliseconds.', array(
      '%count' => $count,
      '%time' => $time,
    ));
    $total = db_result(db_query("SELECT COUNT(nid) FROM {node} WHERE status = 1 {$cond}"));
    $completed = db_result(db_query("SELECT COUNT(nid) FROM {prev_next_node}"));
    $remaining = max(0, $total - $completed);
    drupal_set_message(t('Indexed %count nodes for the Prev/Next index. There are %remaining items left to index.', array(
      '%count' => $count,
      '%remaining' => $remaining,
    )));
  }
}

/**
 * Implementation of hook_block().
 */
function prev_next_block($op = 'list', $delta = 0, $edit = array()) {
  switch ($op) {
    case 'list':
      $num_blocks = variable_get('prev_next_num_blocks', PREV_NEXT_NUM_BLOCKS_DEFAULT);
      for ($b = 0; $b < $num_blocks; $b++) {
        $blocks[$b] = array(
          'info' => t('Prev/Next links !blocknum', array(
            '!blocknum' => 1 + $b,
          )),
          'status' => 0,
          'cache' => BLOCK_CACHE_PER_PAGE,
        );
      }
      return $blocks;
      break;
    case 'configure':
      $description = module_exists('token') ? 'Use the available tokens (see below) to customize the link text.' : 'The [title] token will be replaced by the actual node title.';
      $form['previous'] = array(
        '#type' => 'fieldset',
        '#title' => t('Previous Node'),
        '#collapsible' => TRUE,
      );
      $form['previous']['prev_next_display_prev' . $delta] = array(
        '#type' => 'checkbox',
        '#title' => t('Display'),
        '#default_value' => variable_get('prev_next_display_prev' . $delta, PREV_NEXT_DISPLAY_DEFAULT),
      );
      $form['previous']['prev_next_display_text_prev' . $delta] = array(
        '#type' => 'textfield',
        '#title' => t('Link text'),
        '#description' => $description,
        '#default_value' => variable_get('prev_next_display_text_prev' . $delta, PREV_NEXT_DISPLAY_TEXT_PREV_DEFAULT),
      );
      if (module_exists('token')) {
        $form['previous']['token_help'] = array(
          '#title' => t('Replacement patterns'),
          '#type' => 'fieldset',
          '#collapsible' => TRUE,
          '#collapsed' => TRUE,
        );
        $form['previous']['token_help']['help'] = array(
          '#value' => theme('token_help', 'node'),
        );
      }
      $form['next'] = array(
        '#type' => 'fieldset',
        '#title' => t('Next Node'),
        '#collapsible' => TRUE,
      );
      $form['next']['prev_next_display_next' . $delta] = array(
        '#type' => 'checkbox',
        '#title' => t('Display'),
        '#default_value' => variable_get('prev_next_display_next' . $delta, PREV_NEXT_DISPLAY_DEFAULT),
      );
      $form['next']['prev_next_display_text_next' . $delta] = array(
        '#type' => 'textfield',
        '#title' => t('Link text'),
        '#description' => $description,
        '#default_value' => variable_get('prev_next_display_text_next' . $delta, PREV_NEXT_DISPLAY_TEXT_NEXT_DEFAULT),
      );
      if (module_exists('token')) {
        $form['next']['token_help'] = array(
          '#title' => t('Replacement patterns'),
          '#type' => 'fieldset',
          '#collapsible' => TRUE,
          '#collapsed' => TRUE,
        );
        $form['next']['token_help']['help'] = array(
          '#value' => theme('token_help', 'node'),
        );
      }
      return $form;
      break;
    case 'save':
      variable_set('prev_next_display_prev' . $delta, $edit['prev_next_display_prev' . $delta]);
      variable_set('prev_next_display_next' . $delta, $edit['prev_next_display_next' . $delta]);
      variable_set('prev_next_display_text_prev' . $delta, $edit['prev_next_display_text_prev' . $delta]);
      variable_set('prev_next_display_text_next' . $delta, $edit['prev_next_display_text_next' . $delta]);
      break;
    case 'view':
      $content = '';
      $next_display = variable_get('prev_next_display_next' . $delta, PREV_NEXT_DISPLAY_DEFAULT);
      $next_text = variable_get('prev_next_display_text_next' . $delta, PREV_NEXT_DISPLAY_TEXT_NEXT_DEFAULT);
      $prev_display = variable_get('prev_next_display_prev' . $delta, PREV_NEXT_DISPLAY_DEFAULT);
      $prev_text = variable_get('prev_next_display_text_prev' . $delta, PREV_NEXT_DISPLAY_TEXT_PREV_DEFAULT);
      if (arg(0) == 'node' && is_numeric(arg(1)) && !arg(2)) {
        $node = node_load(arg(1));
        $n_nid = prev_next_nid($node->nid, 'next');
        $p_nid = prev_next_nid($node->nid, 'prev');
        if ($n_nid || $p_nid) {
          if ($p_nid && $prev_display && $prev_text != '') {
            $p_node = node_load($p_nid);
            if (module_exists('token')) {
              $link = token_replace($prev_text, 'node', $p_node);
            }
            else {
              $link = str_replace('[title]', $p_node->title, $prev_text);
            }
            $options = array(
              'html' => TRUE,
            );
            $content .= '<li class="prev-next-link-prev">' . l($link, "node/{$p_nid}", $options) . '</li>';
          }
          if ($n_nid && $next_display && $next_text != '') {
            $n_node = node_load($n_nid);
            if (module_exists('token')) {
              $link = token_replace($next_text, 'node', $n_node);
            }
            else {
              $link = str_replace('[title]', $n_node->title, $next_text);
            }
            $options = array(
              'html' => TRUE,
            );
            $content .= '<li class="prev-next-link-next">' . l($link, "node/{$n_nid}", $options) . '</li>';
          }
          $block = array(
            'subject' => t('Prev/Next links'),
            'content' => '<ul class="prev-next-links">' . $content . '</ul>',
          );
        }
      }
      return $block;
  }
}

/**
 * Create or update the prev_next records.
 */
function _prev_next_add($nid) {
  $node_type = db_result(db_query("SELECT type FROM {node} WHERE nid = %d LIMIT 1", $nid));
  $search_criteria = variable_get(PREV_NEXT_NODE_TYPE . $node_type . '_indexing_criteria', PREV_NEXT_INDEXING_CRITERIA_DEFAULT);
  $criteria_value = db_result(db_query("SELECT %s FROM {node} WHERE nid = %d LIMIT 1", $search_criteria, $nid));
  $cond = _prev_next_node_types_sql($node_type);
  $next_nid = db_result(db_query("SELECT nid FROM {node} WHERE %s > '%s' AND status = 1 {$cond} ORDER BY %s ASC LIMIT 1", $search_criteria, $criteria_value, $search_criteria));
  $prev_nid = db_result(db_query("SELECT nid FROM {node} WHERE %s < '%s' AND status = 1 {$cond} ORDER BY %s DESC LIMIT 1", $search_criteria, $criteria_value, $search_criteria));

  // Update the node-level data
  $exists = db_result(db_query('SELECT COUNT(*) FROM {prev_next_node} WHERE nid = %d', $nid));
  if ($exists) {
    db_query('UPDATE {prev_next_node} SET prev_nid = %d, next_nid = %d, changed = %d WHERE nid = %d', $prev_nid, $next_nid, time(), $nid);
  }
  else {
    db_query('INSERT INTO {prev_next_node} (prev_nid, next_nid, changed, nid) VALUES (%d, %d, %d, %d)', $prev_nid, $next_nid, time(), $nid);
  }

  // Update the other nodes pointing to this node
  foreach (node_get_types() as $type => $name) {
    if (variable_get(PREV_NEXT_NODE_TYPE . $type, 0)) {
      $search_criteria = variable_get(PREV_NEXT_NODE_TYPE . $type . '_indexing_criteria', PREV_NEXT_INDEXING_CRITERIA_DEFAULT);
      $criteria_value = db_result(db_query("SELECT %s FROM {node} WHERE nid = %d LIMIT 1", $search_criteria, $nid));
      $cond = _prev_next_node_types_sql($node_type);
      $next_nid = db_result(db_query("SELECT nid FROM {node} WHERE %s < '%s' AND status = 1 {$cond} ORDER BY %s DESC LIMIT 1", $search_criteria, $criteria_value, $search_criteria));
      if ($next_nid) {
        db_query("UPDATE {prev_next_node} SET next_nid = %d WHERE nid = %d", $nid, $next_nid);
      }
      $prev_nid = db_result(db_query("SELECT nid FROM {node} WHERE %s > '%s' AND status = 1 {$cond} ORDER BY %s ASC LIMIT 1", $search_criteria, $criteria_value, $search_criteria));
      if ($prev_nid) {
        db_query("UPDATE {prev_next_node} SET prev_nid = %d WHERE nid = %d", $nid, $prev_nid);
      }
    }
  }
}

/**
 * Update the prev_next records.
 */
function _prev_next_modify($nid) {

  // Find out if any other nodes point to this node and update them
  _prev_next_modify_pointing_nodes($nid);

  // Then update this one
  _prev_next_add($nid);
}

/**
 * Delete from the prev_next records.
 */
function _prev_next_remove($nid) {

  // Find if there is an entry for this node
  $node = db_fetch_object(db_query("SELECT nid, prev_nid, next_nid, changed FROM {prev_next_node} WHERE nid = %d", $nid));
  if ($node) {

    // Delete the data for this node
    db_query("DELETE FROM {prev_next_node} WHERE nid = %d", $nid);
  }

  // Find out if any other nodes point to this node and update them
  _prev_next_modify_pointing_nodes($nid);
}

/**
 * Update other nodes pointing to a particular node
 */
function _prev_next_modify_pointing_nodes($nid) {

  // First for previous
  $result = db_query("SELECT nid FROM {prev_next_node} WHERE prev_nid = %d", $nid);
  while ($prev_row = db_fetch_object($result)) {
    _prev_next_add($prev_row->nid);
  }

  // Then for next
  $result = db_query("SELECT nid FROM {prev_next_node} WHERE next_nid = %d", $nid);
  while ($next_row = db_fetch_object($result)) {
    _prev_next_add($next_row->nid);
  }
}

/**
 * Implementation of hook_nodeapi().
 */
function prev_next_nodeapi(&$node, $op) {
  $found = FALSE;
  foreach (_prev_next_node_types() as $type) {
    if ($node->type == $type) {
      $found = TRUE;
      break;
    }
  }
  if (!$found) {
    return;
  }
  switch ($op) {
    case 'insert':
      _prev_next_add($node->nid);
      break;
    case 'update':
      _prev_next_modify($node->nid);
      break;
    case 'delete':
      _prev_next_remove($node->nid);
      break;
  }
}

/*
 * Callable API function to get the next/prev nid of a given nid
 */
function prev_next_nid($nid, $op = 'next') {
  foreach (module_implements('prev_next_nid') as $module) {
    $function = $module . '_prev_next_nid';
    $ret = $function($nid, $op);
    if ($ret !== FALSE) {

      // If the function returns FALSE, keep trying other methods
      return $ret;
    }
  }
  if ($op == 'prev') {
    return prev_next_nid_prev($nid);
  }
  elseif ($op == 'next') {
    return prev_next_nid_next($nid);
  }
  else {
    return 0;
  }
}
function prev_next_nid_next($nid) {
  return db_result(db_query("SELECT next_nid FROM {prev_next_node} WHERE nid = %d", $nid));
}
function prev_next_nid_prev($nid) {
  return db_result(db_query("SELECT prev_nid FROM {prev_next_node} WHERE nid = %d", $nid));
}

/*
 * Helper function to return an array of node types to index
 */
function _prev_next_node_types() {
  $types = array();
  foreach (node_get_types() as $type => $name) {
    if (variable_get(PREV_NEXT_NODE_TYPE . $type, 0)) {
      $types[] = $type;
    }
  }
  return $types;
}

/*
 * Helper function to return a SQL clause for types to be indexed
 */
function _prev_next_node_types_sql($node_type = '') {
  $same_type = variable_get(PREV_NEXT_NODE_TYPE . $node_type . '_same_type', 0);
  if (!$same_type) {
    $types = _prev_next_node_types();
    $quoted_types = array();
    foreach (_prev_next_node_types() as $type) {
      $quoted_types[] = "'" . $type . "'";
    }
    $cond = '';
    if (count($types)) {
      $cond = ' AND type IN (' . implode(',', $quoted_types) . ')';
    }
  }
  else {
    $cond = " AND type = '" . $node_type . "'";
  }
  return $cond;
}
Functions

Name	Description
prev_next_admin	Menu callback argument. Creates the prev_next administration form.
prev_next_admin_submit	Submit callback.
prev_next_admin_validate	Validate callback.
prev_next_block	Implementation of hook_block().
prev_next_cron	Implementation of hook_cron().
prev_next_menu	Implementation of hook_menu().
prev_next_nid
prev_next_nid_next
prev_next_nid_prev
prev_next_nodeapi	Implementation of hook_nodeapi().
prev_next_reindex
prev_next_reindex_confirm
prev_next_reindex_confirm_submit
_prev_next_add	Create or update the prev_next records.
_prev_next_modify	Update the prev_next records.
_prev_next_modify_pointing_nodes	Update other nodes pointing to a particular node
_prev_next_node_types
_prev_next_node_types_sql
_prev_next_remove	Delete from the prev_next records.
Constants

Name	Description
PREV_NEXT_BATCH_SIZE_DEFAULT
PREV_NEXT_DISPLAY_DEFAULT
PREV_NEXT_DISPLAY_TEXT_NEXT_DEFAULT
PREV_NEXT_DISPLAY_TEXT_PREV_DEFAULT
PREV_NEXT_INDEXING_CRITERIA_DEFAULT
PREV_NEXT_NODE_TYPE
PREV_NEXT_NUM_BLOCKS_DEFAULT
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prev_next.module in Previous/Next API 6

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