taxonomy.module

<?php
// $Id$

/**
 * Implementation of hook_perm().
 */
function taxonomy_perm() {
  return array('administer taxonomy');
}

/**
 * Implementation of hook_link().
 *
 * This hook is extended with $type = 'taxonomy terms' to allow themes to
 * print lists of terms associated with a node. Themes can print taxonomy
 * links with:
 *
 * if (module_exist('taxonomy')) {
 *   $this->links(taxonomy_link('taxonomy terms', $node));
 * }
 */
function taxonomy_link($type, $node = NULL) {
  if ($type == 'taxonomy terms' && $node != NULL) {
    $links = array();
    if (array_key_exists('taxonomy', $node)) {
      foreach ($node->taxonomy as $tid) {
        $term = taxonomy_get_term($tid);
        $links[] = l($term->name, 'taxonomy/term/'. $term->tid, $term->description ? array ('title' => $term->description) : array());
      }
    }
    else {
      $links = array();
      foreach (taxonomy_node_get_terms($node->nid) as $term) {
        $links[] = l($term->name, 'taxonomy/term/'. $term->tid, $term->description ? array ('title' => $term->description) : array());
      }

    }
    return $links;
  }
}

/**
 * Implementation of hook_menu().
 */
function taxonomy_menu() {
  $items = array();
  $items[] = array('path' => 'admin/taxonomy', 'title' => t('categories'),
    'callback' => 'taxonomy_admin',
    'access' => user_access('administer taxonomy'));
  $items[] = array('path' => 'admin/taxonomy/list', 'title' => t('list'),
    'type' => MENU_DEFAULT_LOCAL_TASK, 'weight' => -10);
  $items[] = array('path' => 'admin/taxonomy/add/vocabulary', 'title' => t('add vocabulary'),
    'callback' => 'taxonomy_admin',
    'access' => user_access('administer taxonomy'),
    'type' => MENU_LOCAL_TASK);

  $items[] = array('path' => 'taxonomy/term', 'title' => t('taxonomy term'),
    'callback' => 'taxonomy_term_page',
    'access' => user_access('access content'),
    'type' => MENU_CALLBACK);
  return $items;
}

/**
 * Implementation of hook_block().
 *
 * Generates a block with all categories.
 */
function taxonomy_block($op = 'list', $delta = 0) {
  if ($op == 'list') {
    $blocks[0]['info'] = t('Categories');
    return $blocks;
  }
  else if (user_access('access content')) {
    $result = db_query("SELECT d.tid, d.name, MAX(n.created) AS updated, COUNT(*) AS count FROM {term_data} d INNER JOIN {term_node} USING (tid) INNER JOIN {node} n USING (nid) WHERE n.status = 1 GROUP BY d.tid ORDER BY updated DESC, d.name");
    $items = array();
    while ($category = db_fetch_object($result)) {
      $items[] = l("$category->name ($category->count)", 'taxonomy/term/'. $category->tid) .'<br />'. format_interval(time() - $category->updated) .' '. t('ago');
    }

    $block['subject'] = t('Categories');
    $block['content'] = theme('item_list', $items);
    return $block;
  }
}

function taxonomy_form_vocabulary($edit = array()) {
  foreach (node_list() as $type) {
    $nodetypes[$type] = node_invoke($type, 'node_name');
  }

  $form .= form_textfield(t('Vocabulary name'), 'name', $edit['name'], 50, 64, t('The name for this vocabulary.  Example: "Topic".'), NULL, TRUE);
  $form .= form_textarea(t('Description'), 'description', $edit['description'], 60, 5, t('Description of the vocabulary; can be used by modules.'));
  $form .= form_textfield(t('Help text'), 'help', $edit['help'], 50, 255, t('Instructions to present to the user when choosing a term.'));
  $form .= form_checkboxes(t('Types'), 'nodes', explode(',', $edit['nodes']), $nodetypes, t('A list of node types you want to associate with this vocabulary.'), NULL, TRUE);
  $form .= form_checkbox(t('Related terms'), 'relations', 1, $edit['relations'], t('Allows <a href="%help-url">related terms</a> in this vocabulary.', array('%help-url' => url('admin/taxonomy/help', NULL, NULL, 'related-terms'))));
  $form .= form_radios(t('Hierarchy'), 'hierarchy', $edit['hierarchy'], array(t('Disabled'), t('Single'), t('Multiple')), t('Allows <a href="%help-url">a tree-like hierarchy</a> between terms of this vocabulary.', array('%help-url' => url('admin/taxonomy/help', NULL, NULL, 'hierarchy'))));
  $form .= form_checkbox(t('Multiple select'), 'multiple', 1, $edit['multiple'], t('Allows nodes to have more than one term in this vocabulary.'));
  $form .= form_checkbox(t('Required'), 'required', 1, $edit['required'], t('If enabled, every node <strong>must</strong> have at least one term in this vocabulary.'));
  $form .= form_weight(t('Weight'), 'weight', $edit['weight'], 10, t('In listings, the heavier vocabularies will sink and the lighter vocabularies will be positioned nearer the top.'));
  $form .= form_submit(t('Submit'));

  if ($edit['vid']) {
    $form .= form_submit(t('Delete'));
    $form .= form_hidden('vid', $edit['vid']);
  }

  return form($form);
}

function taxonomy_save_vocabulary($edit) {
  if (!$edit['nodes']) {
    $edit['nodes'] = array();
  }

  $data = array('name' => $edit['name'], 'nodes' => implode(',', $edit['nodes']), 'description' => $edit['description'], 'help' => $edit['help'], 'multiple' => $edit['multiple'], 'required' => $edit['required'], 'hierarchy' => $edit['hierarchy'], 'relations' => $edit['relations'], 'weight' => $edit['weight']);
  if ($edit['vid'] && $edit['name']) {
    db_query('UPDATE {vocabulary} SET '. _taxonomy_prepare_update($data) .' WHERE vid = %d', $edit['vid']);
    module_invoke_all('taxonomy', 'update', 'vocabulary', $edit);
    $message = t('updated vocabulary "%name".', array('%name' => $edit['name']));
  }
  else if ($edit['vid']) {
    $message = taxonomy_del_vocabulary($edit['vid']);
  }
  else {
    $data['vid'] = $edit['vid'] = db_next_id('{vocabulary}_vid');
    db_query('INSERT INTO {vocabulary} '. _taxonomy_prepare_insert($data, 1) .' VALUES '. _taxonomy_prepare_insert($data, 2));
    module_invoke_all('taxonomy', 'insert', 'vocabulary', $edit);
    $message = t('created new vocabulary "%name".', array('%name' => $edit['name']));
  }

  cache_clear_all();

  drupal_set_message($message);

  return $edit;
}

function taxonomy_del_vocabulary($vid) {
  $vocabulary = taxonomy_get_vocabulary($vid);

  db_query('DELETE FROM {vocabulary} WHERE vid = %d', $vid);
  $result = db_query('SELECT tid FROM {term_data} WHERE vid = %d', $vid);
  while ($term = db_fetch_object($result)) {
    taxonomy_del_term($term->tid);
  }

  module_invoke_all('taxonomy', 'delete', 'vocabulary', $vocabulary);

  cache_clear_all();

  return t('deleted vocabulary "%name".', array('%name' => $vocabulary->name));
}

function _taxonomy_confirm_del_vocabulary($vid) {
  $vocabulary = taxonomy_get_vocabulary($vid);

  $form .= form_hidden('confirm', 1);
  $form .= form_hidden('type', 'vocabulary');
  $form .= form_hidden('vid', $vid);
  $form .= form_submit(t('Delete'));
  $form .= form_submit(t('Cancel'));

  return form(form_item(t('Delete vocabulary "%name"', array('%name' => $vocabulary->name)), $form, t('Are you sure you want to delete the vocabulary and all its terms?')));
}

function taxonomy_form_term($edit = array()) {
  $vocabulary_id = isset($edit['vid']) ? $edit['vid'] : arg(4);
  $vocabulary = taxonomy_get_vocabulary($vocabulary_id);

  $form = form_textfield(t('Term name'), 'name', $edit['name'], 50, 64, t('The name for this term.  Example: "Linux".'), NULL, TRUE);
  $form .= form_textarea(t('Description'), 'description', $edit['description'], 60, 5, t('A description of the term.'));

  if ($vocabulary->hierarchy) {
    $parent = array_keys(taxonomy_get_parents($edit['tid']));
    $children = taxonomy_get_tree($vocabulary_id, $edit['tid']);

    // A term can't be the child of itself, nor of its children.
    foreach ($children as $child) {
      $exclude[] = $child->tid;
    }
    $exclude[] = $edit['tid'];

    if ($vocabulary->hierarchy == 1) {
      $form .= _taxonomy_term_select(t('Parent'), 'parent', $parent, $vocabulary_id, l(t('Parent term'), 'admin/taxonomy/help', NULL, NULL, 'parent') .'.', 0, '<'. t('root') .'>', $exclude);
    }
    elseif ($vocabulary->hierarchy == 2) {
      $form .= _taxonomy_term_select(t('Parents'), 'parent', $parent, $vocabulary_id, l(t('Parent terms'), 'admin/taxonomy/help', NULL, NULL, 'parent') .'.', 1, '<'. t('root') .'>', $exclude);
    }
  }

  if ($vocabulary->relations) {
    $form .= _taxonomy_term_select(t('Related terms'), 'relations', array_keys(taxonomy_get_related($edit['tid'])), $vocabulary_id, NULL, 1, '<'. t('none') .'>', array($edit['tid']));
  }

  $form .= form_textarea(t('Synonyms'), 'synonyms', implode("\n", taxonomy_get_synonyms($edit['tid'])), 30, 5, t('<a href="%help-url">Synonyms</a> of this term, one synonym per line.', array('%help-url' => url('admin/taxonomy/help', NULL, NULL, 'synonyms'))));
  $form .= form_weight(t('Weight'), 'weight', $edit['weight'], 10, t('In listings, the heavier terms will sink and the lighter terms will be positioned nearer the top.'));
  $form .= form_hidden('vid', $vocabulary->vid);
  $form .= form_submit(t('Submit'));

  if ($edit['tid']) {
    $form .= form_submit(t('Delete'));
    $form .= form_hidden('tid', $edit['tid']);
  }

  return form($form);
}

function taxonomy_save_term($edit) {
  if ($edit['tid'] && $edit['name']) {
    $data = array('name' => $edit['name'], 'description' => $edit['description'], 'weight' => $edit['weight']);

    db_query('UPDATE {term_data} SET '. _taxonomy_prepare_update($data) .' WHERE tid = %d', $edit['tid']);
    module_invoke_all('taxonomy', 'update', 'term', $edit);
    $message = t('the term "%a" has been updated.', array('%a' => $edit['name']));
  }
  else if ($edit['tid']) {
    return taxonomy_del_term($edit['tid']);
  }
  else {
    $edit['tid'] = db_next_id('{term_data}_tid');
    $data = array('tid' => $edit['tid'], 'name' => $edit['name'], 'description' => $edit['description'], 'vid' => $edit['vid'], 'weight' => $edit['weight']);
    db_query('INSERT INTO {term_data} '. _taxonomy_prepare_insert($data, 1) .' VALUES '. _taxonomy_prepare_insert($data, 2));
    module_invoke_all('taxonomy', 'insert', 'term', $edit);
    $message = t('created new term "%name".', array('%name' => $edit['name']));
  }

  db_query('DELETE FROM {term_relation} WHERE tid1 = %d OR tid2 = %d', $edit['tid'], $edit['tid']);
  if ($edit['relations']) {
    foreach ($edit['relations'] as $related_id) {
      if ($related_id != 0) {
        db_query('INSERT INTO {term_relation} (tid1, tid2) VALUES (%d, %d)', $edit['tid'], $related_id);
      }
    }
  }

  db_query('DELETE FROM {term_hierarchy} WHERE tid = %d', $edit['tid']);
  if (!isset($edit['parent'])) {
    $edit['parent'] = 0;
  }
  if (is_array($edit['parent'])) {
    foreach ($edit['parent'] as $parent) {
      db_query('INSERT INTO {term_hierarchy} (tid, parent) VALUES (%d, %d)', $edit['tid'], $parent);
    }
  }
  else {
    db_query('INSERT INTO {term_hierarchy} (tid, parent) VALUES (%d, %d)', $edit['tid'], $edit['parent'][0]);
  }

  db_query('DELETE FROM {term_synonym} WHERE tid = %d', $edit['tid']);
  if ($edit['synonyms']) {
    foreach (explode ("\n", str_replace("\r", '', $edit['synonyms'])) as $synonym) {
      if ($synonym) {
        db_query("INSERT INTO {term_synonym} (tid, name) VALUES (%d, '%s')", $edit['tid'], chop($synonym));
      }
    }
  }

  cache_clear_all();

  drupal_set_message($message);
  return $edit;
}

function taxonomy_del_term($tid) {
  $term = taxonomy_get_term($tid);

  db_query('DELETE FROM {term_data} WHERE tid = %d', $tid);
  db_query('DELETE FROM {term_hierarchy} WHERE tid = %d', $tid);
  db_query('DELETE FROM {term_relation} WHERE tid1 = %d OR tid2 = %d', $tid, $tid);
  db_query('DELETE FROM {term_synonym} WHERE tid = %d', $tid);
  db_query('DELETE FROM {term_node} WHERE tid = %d', $tid);

  module_invoke_all('taxonomy', 'delete', 'term', $term);

  cache_clear_all();

  return t('deleted term "%name".', array('%name' => $term->name));
}

function _taxonomy_confirm_del_term($tid) {
  $term = taxonomy_get_term($tid);

  $form .= form_hidden('confirm', 1);
  $form .= form_hidden('type', 'term');
  $form .= form_hidden('tid', $tid);
  $form .= form_submit(t('Delete'));
  $form .= form_submit(t('Cancel'));

  return form(form_item(t('Delete term "%name"', array('%name' => $term->name)), $form, t('Are you sure you want to delete the term?')));
}

/**
 * Generate a tabular listing of administrative functions for vocabularies.
 */
function taxonomy_overview() {
  $header = array(t('name'), t('node types'), array('data' => t('operations'), 'colspan' => 3));

  $vocabularies = taxonomy_get_vocabularies();

  foreach ($vocabularies as $vocabulary) {
    $links = array();
    $types = array();
    foreach(explode(',', $vocabulary->nodes) as $type) {
      $types[] = node_invoke($type, 'node_name');
    }
    $rows[] = array($vocabulary->name, array('data' => implode(', ', $types), 'align' => 'center'), l(t('edit vocabulary'), "admin/taxonomy/edit/vocabulary/$vocabulary->vid"), l(t('add term'), "admin/taxonomy/add/term/$vocabulary->vid"), l(t('preview form'), "admin/taxonomy/preview/vocabulary/$vocabulary->vid"));

    $tree = taxonomy_get_tree($vocabulary->vid);
    if ($tree) {
      unset($data);
      foreach ($tree as $term) {
        $data .= _taxonomy_depth($term->depth) .' '. $term->name .' ('. l(t('edit term'), "admin/taxonomy/edit/term/$term->tid") .')<br />';
      }
      $rows[] = array(array('data' => $data, 'colspan' => 5));
    }
  }

  return theme('table', $header, $rows);
}

/**
 * Generate a form element for selecting terms from a vocabulary.
 */
function taxonomy_form($vid, $value = 0, $help = NULL, $name = 'taxonomy') {
  $vocabulary = taxonomy_get_vocabulary($vid);
  $help = ($help) ? $help : $vocabulary->help;
  if ($vocabulary->required) {
    $blank = 0;
  }
  else {
    $blank = '<'. t('none') .'>';
  }

  return _taxonomy_term_select($vocabulary->name, $name, $value, $vid, $help, intval($vocabulary->multiple), $blank);
}

/**
 * Return an array of all vocabulary objects.
 *
 * @param $type
 *   If set, return only those vocabularies associated with this node type.
 */
function taxonomy_get_vocabularies($type = '', $key = 'vid') {
  if ($type) {
    $result = db_query("SELECT * FROM {vocabulary} WHERE nodes LIKE '%%%s%%' ORDER BY weight, name", $type);
  }
  else {
    $result = db_query('SELECT * FROM {vocabulary} ORDER BY weight, name');
  }
  $vocabularies = array();
  while ($voc = db_fetch_object($result)) {
    $vocabularies[$voc->$key] = $voc;
  }

  return $vocabularies;
}

/**
 * Generate a form for selecting terms to associate with a node.
 */
function taxonomy_node_form($type, $node = '', $help = NULL, $name = 'taxonomy') {
  if (!$node->taxonomy) {
    if ($node->nid) {
      $terms = array_keys(taxonomy_node_get_terms($node->nid));
    }
    else {
      $terms = 0;
    }
  }
  else {
    $terms = $node->taxonomy;
  }

  $c = db_query("SELECT * FROM {vocabulary} WHERE nodes LIKE '%%%s%%' ORDER BY weight, name", $type);
  while ($vocabulary = db_fetch_object($c)) {
    $result[] = taxonomy_form($vocabulary->vid, $terms, $help, $name);
  }
  return $result ? $result : array();
}

/**
 * Determine whether a node mentions the name of a term.
 */
function taxonomy_node_has_term($nid, $tid) {
  $term_name = db_result(db_query('SELECT name FROM {term_data} WHERE tid = %d', $tid));

  return db_result(db_query("SELECT COUNT(n.nid) FROM {node} n WHERE n.nid = %d AND ((n.body LIKE '%%%s%%') OR (n.body LIKE '%%%s%%'))", $nid, $term_name, $term_name));
}

/**
 * Find all terms associated to the given node, within one vocabulary.
 */
function taxonomy_node_get_terms_by_vocabulary($nid, $vid, $key = 'tid') {
  $result = db_query('SELECT t.* FROM {term_data} t, {term_node} r WHERE t.tid = r.tid AND t.vid = %d AND r.nid = %d ORDER BY weight', $vid, $nid);
  $terms = array();
  while ($term = db_fetch_object($result)) {
    $terms[$term->$key] = $term;
  }
  return $terms;
}

/**
 * Find all terms associated to the given node.
 */
function taxonomy_node_get_terms($nid, $key = 'tid') {
  static $terms;

  if (!isset($terms[$nid])) {
    $result = db_query('SELECT t.* FROM {term_data} t, {term_node} r WHERE r.tid = t.tid AND r.nid = %d ORDER BY weight, name', $nid);
    $terms[$nid] = array();
    while ($term = db_fetch_object($result)) {
      $terms[$nid][$term->$key] = $term;
    }
  }
  return $terms[$nid];
}

/**
 * Save term associations for a given node.
 */
function taxonomy_node_save($nid, $terms) {
  taxonomy_node_delete($nid);

  if ($terms) {
    foreach ($terms as $term) {
      if ($term) {
        db_query('INSERT INTO {term_node} (nid, tid) VALUES (%d, %d)', $nid, $term);
      }
    }
  }
}

/**
 * Remove associations of a node to its terms.
 */
function taxonomy_node_delete($nid) {
  db_query('DELETE FROM {term_node} WHERE nid = %d', $nid);
}

/**
 * Find all term objects related to a given term ID.
 */
function taxonomy_get_related($tid, $key = 'tid') {
  if ($tid) {
    $result = db_query('SELECT t.*, tid1, tid2 FROM {term_relation}, {term_data} t WHERE (t.tid = tid1 OR t.tid = tid2) AND (tid1 = %d OR tid2 = %d) AND t.tid != %d ORDER BY weight, name', $tid, $tid, $tid);
    $related = array();
    while ($term = db_fetch_object($result)) {
      $related[$term->$key] = $term;
    }
    return $related;
  }
  else {
    return array();
  }
}

/**
 * Find all parents of a given term ID.
 */
function taxonomy_get_parents($tid, $key = 'tid') {
  if ($tid) {
    $result = db_query('SELECT t.* FROM {term_hierarchy} h, {term_data} t WHERE h.parent = t.tid AND h.tid = %d ORDER BY weight, name', $tid);
    $parents = array();
    while ($parent = db_fetch_object($result)) {
      $parents[$parent->$key] = $parent;
    }
    return $parents;
  }
  else {
    return array();
  }
}

/**
 * Find all ancestors of a given term ID.
 */
function taxonomy_get_parents_all($tid) {
  $parents = array();
  if ($tid) {
    $parents[] = taxonomy_get_term($tid);
    $n = 0;
    while ($parent = taxonomy_get_parents($parents[$n]->tid)) {
      $parents = array_merge($parents, $parent);
      $n++;
    }
  }
  return $parents;
}

/**
 * Find all children of a term ID.
 */
function taxonomy_get_children($tid, $vid = 0, $key = 'tid') {
  if ($vid) {
    $result = db_query('SELECT t.* FROM {term_hierarchy} h, {term_data} t WHERE t.vid = %d AND h.tid = t.tid AND h.parent = %d ORDER BY weight, name', $vid, $tid);
  }
  else {
    $result = db_query('SELECT t.* FROM {term_hierarchy} h, {term_data} t WHERE h.tid = t.tid AND parent = %d ORDER BY weight', $tid);
  }
  $children = array();
  while ($term = db_fetch_object($result)) {
    $children[$term->$key] = $term;
  }
  return $children;
}

/**
 * Create a hierarchical representation of a vocabulary.
 *
 * @param $vid
 *   Which vocabulary to generate the tree for.
 *
 * @param $parent
 *   The term ID under which to generate the tree. If 0, generate the tree
 *   for the entire vocabulary.
 *
 * @param $depth
 *   Internal use only.
 *
 * @param $max_depth
 *   The number of levels of the tree to return. Leave NULL to return all levels.
 *
 * @return
 *   An array of all term objects in the tree. Each term object is extended
 *   to have "depth" and "parents" attributes in addition to its normal ones.
 */
function taxonomy_get_tree($vid, $parent = 0, $depth = -1, $max_depth = NULL) {
  static $children, $parents, $terms;

  $depth++;

  // We cache trees, so it's not CPU-intensive to call get_tree() on a term
  // and its children, too.
  if (!isset($children[$vid])) {
    $children[$vid] = array();

    $result = db_query('SELECT t.*, parent FROM {term_data} t, {term_hierarchy} h WHERE t.tid = h.tid AND t.vid = %d ORDER BY weight, name', $vid);
    while ($term = db_fetch_object($result)) {
      $children[$vid][$term->parent][] = $term->tid;
      $parents[$vid][$term->tid][] = $term->parent;
      $terms[$vid][$term->tid] = $term;
    }
  }

  $max_depth = (is_null($max_depth)) ? count($children[$vid]) : $max_depth;
  if ($children[$vid][$parent]) {
    foreach ($children[$vid][$parent] as $child) {
      if ($max_depth > $depth) {
        $terms[$vid][$child]->depth = $depth;
        // The "parent" attribute is not useful, as it would show one parent only.
        unset($terms[$vid][$child]->parent);
        $terms[$vid][$child]->parents = $parents[$vid][$child];
        $tree[] = $terms[$vid][$child];

        $tree = array_merge($tree, taxonomy_get_tree($vid, $child, $depth, $max_depth));
      }
    }
  }

  return $tree ? $tree : array();
}

/**
 * Return an array of synonyms of the given term ID.
 */
function taxonomy_get_synonyms($tid) {
  if ($tid) {
    $result = db_query('SELECT name FROM {term_synonym} WHERE tid = %d', $tid);
    while ($synonym = db_fetch_array($result)) {
      $synonyms[] = $synonym['name'];
    }
    return $synonyms ? $synonyms : array();
  }
  else {
    return array();
  }
}

/**
 * Return the term object that has the given string as a synonym.
 */
function taxonomy_get_synonym_root($synonym) {
  return db_fetch_object(db_query("SELECT * FROM {term_synonym} s, {term_data} t WHERE t.tid = s.tid AND s.name = '%s'", $synonym));
}

/**
 * Given a term id, count the number of published nodes in it.
 */
function taxonomy_term_count_nodes($tid, $type = 0) {
  static $count;

  if (!isset($count[$type])) {
    // $type == 0 always evaluates true is $type is a string
    if (is_numeric($type)) {
      $result = db_query('SELECT t.tid, COUNT(*) AS c FROM {term_node} t INNER JOIN {node} n ON t.nid = n.nid WHERE n.status = 1 GROUP BY t.tid');
    }
    else {
      $result = db_query("SELECT t.tid, COUNT(*) AS c FROM {term_node} t, {node} n WHERE t.nid = n.nid AND n.status = 1 AND n.type = '%s' GROUP BY t.tid", $type);
    }
    while ($term = db_fetch_object($result)) {
      $count[$type][$term->tid] = $term->c;
    }
  }

  foreach (_taxonomy_term_children($tid) as $c) {
    $children_count += taxonomy_term_count_nodes($c, $type);
  }
  return $count[$type][$tid] + $children_count;
}

/**
 * Helper for taxonomy_term_count_nodes().
 */
function _taxonomy_term_children($tid) {
  static $children;

  if (!isset($children)) {
    $result = db_query('SELECT tid, parent FROM {term_hierarchy}');
    while ($term = db_fetch_object($result)) {
      $children[$term->parent][] = $term->tid;
    }
  }
  return $children[$tid] ? $children[$tid] : array();
}

/**
 * Try to map a string to an existing vocabulary.
 *
 * Provides a case-insensitive and trimmed mapping, to maximize the
 * likelihood of a successful match.
 *
 * @param name
 *   Name of the vocabulary to search for.
 *
 * @return
 *   An array of matching vocabulary objects.
 */
function taxonomy_get_vocabulary_by_name($name) {
  $db_result = db_query("SELECT * FROM {vocabulary} WHERE LOWER('%s') LIKE LOWER(name)", trim($name));
  $result = array();
  while ($vocabulary = db_fetch_object($db_result)) {
    $result[] = $vocabulary;
  }

  return $result;
}

/**
 * Try to map a string to an existing term, as for glossary use.
 *
 * Provides a case-insensitive and trimmed mapping, to maximize the
 * likelihood of a successful match.
 *
 * @param name
 *   Name of the term to search for.
 *
 * @return
 *   An array of matching term objects.
 */
function taxonomy_get_term_by_name($name) {
  $db_result = db_query("SELECT * FROM {term_data} WHERE LOWER('%s') LIKE LOWER(name)", trim($name));
  $result = array();
  while ($term = db_fetch_object($db_result)) {
    $result[] = $term;
  }

  return $result;
}

/**
 * Return the vocabulary object matching a vocabulary ID.
 */
function taxonomy_get_vocabulary($vid) {
  return db_fetch_object(db_query('SELECT * FROM {vocabulary} WHERE vid = %d', $vid));
}

/**
 * Return the term object matching a term ID.
 */
function taxonomy_get_term($tid) {
  // simple cache using a static var?
  return db_fetch_object(db_query('SELECT * FROM {term_data} WHERE tid = %d', $tid));
}

function _taxonomy_term_select($title, $name, $value, $vocabulary_id, $description, $multiple, $blank, $exclude = array()) {
  $tree = taxonomy_get_tree($vocabulary_id);
  if ($blank) {
    $options[] = array('tid' => 0, 'name' => $blank);
  }
  if ($tree) {
    foreach ($tree as $term) {
      if (!in_array($term->tid, $exclude)) {
        $options[] = array('tid' => $term->tid, 'name' => _taxonomy_depth($term->depth, '-').$term->name);
      }
    }
    if (!$blank && !$value) {
      // required but without a predefined value, so set first as predefined
      $value = $tree[0]->tid;
    }
  }

  if (count($options) > 0) {
    foreach ($options as $option) {
      $select .= '<option value="'. $option['tid'] .'"'. (is_array($value) ? (in_array($option['tid'], $value) ? ' selected="selected"' : '') : ($option['tid'] == $value ? ' selected="selected"' : '')) .'>'. check_form($option['name']) .'</option>';
    }

    $size = min(12, count($options));

    return form_item($title, "<select name=\"edit[$name][]\"". ($multiple ? " multiple=\"multiple\" size=\"$size\"" : '') . ($extra ? " $extra" : '') .' class="'. _form_get_class('', false, _form_get_error($name)) ."\">$select</select>", $description, NULL, false, _form_get_error($name));
  }
}

function _taxonomy_depth($depth, $graphic = '--') {
  for ($n = 0; $n < $depth; $n++) {
    $result .= $graphic;
  }
  return $result;
}

function _taxonomy_prepare_update($data) {
  foreach ($data as $key => $value) {
    $q[] = "$key = '". check_query($value) ."'";
  }
  $result = implode(', ', $q);
  return $result;
}

function _taxonomy_prepare_insert($data, $stage) {
  if ($stage == 1) {
    $result = implode(', ', array_keys($data));
  }
  else {
    foreach (array_values($data) as $value) {
      $q[] = "'". check_query($value) ."'";
    }
    $result = implode(', ', $q);
  }
  return "($result)";
}

/**
 * Finds all nodes that match selected taxonomy conditions.
 *
 * @param $tids
 *   An array of term IDs to match.
 * @param $operator
 *   How to interpret multiple IDs in the array. Can be "or" or "and".
 * @param $depth
 *   How many levels deep to traverse the taxonomy tree. Can be a nonnegative
 *   integer or "all".
 * @param $pager
 *   Whether the nodes are to be used with a pager (the case on most Drupal
 *   pages) or not (in an XML feed, for example).
 * @return
 *   A resource identifier pointing to the query results.
 */
function taxonomy_select_nodes($tids = array(), $operator = 'or', $depth = 0, $pager = TRUE) {
  if (count($tids) > 0) {
    // For each term ID, generate an array of descendant term IDs to the right depth.
    $descendant_tids = array();
    if ($depth === 'all') {
      $depth = NULL;
    }
    foreach ($tids as $index => $tid) {
      $term = taxonomy_get_term($tid);
      $tree = taxonomy_get_tree($term->vid, $tid, -1, $depth);
      $descendant_tids[] = array_merge($tid, array_map('_taxonomy_get_tid_from_term', $tree));
    }

    if ($operator == 'or') {
      $str_tids = implode(',', call_user_func_array('array_merge', $descendant_tids));
      $sql = 'SELECT DISTINCT(n.nid) FROM {node} n '. node_access_join_sql() .' INNER JOIN {term_node} tn ON n.nid = tn.nid WHERE tn.tid IN ('. $str_tids .') AND n.status = 1 AND '. node_access_where_sql() .' ORDER BY n.sticky DESC, n.created DESC';
      $sql_count = 'SELECT COUNT(DISTINCT(n.nid)) FROM {node} n '. node_access_join_sql() .' INNER JOIN {term_node} tn ON n.nid = tn.nid WHERE tn.tid IN ('. $str_tids .') AND n.status = 1 AND '. node_access_where_sql();
    }
    else {
      $joins = '';
      $wheres = '';
      foreach ($descendant_tids as $index => $tids) {
        $joins .= ' INNER JOIN {term_node} tn'. $index .' ON n.nid = tn'. $index .'.nid';
        $wheres .= ' AND tn'. $index .'.tid IN ('. implode(',', $tids) .')';
      }
      $sql = 'SELECT DISTINCT(n.nid) FROM {node} n '. node_access_join_sql() . $joins .' WHERE n.status = 1 AND '. node_access_where_sql() . $wheres .' ORDER BY n.sticky DESC, n.created DESC';
      $sql_count = 'SELECT COUNT(DISTINCT(n.nid)) FROM {node} n '. node_access_join_sql() . $joins .' WHERE n.status = 1 AND '. node_access_where_sql() . $wheres;
    }

    if ($pager) {
      $result = pager_query($sql, variable_get('default_nodes_main', 10) , 0, $sql_count);
    }
    else {
      $result = db_query_range($sql, 0, 15);
    }
  }

  return $result;
}

/**
 * Accepts the result of a pager_query() call, such as that performed by
 * taxonomy_select_nodes(), and formats each node along with a pager.
*/
function taxonomy_render_nodes($result) {

  while ($node = db_fetch_object($result)) {
    $output .= node_view(node_load(array('nid' => $node->nid)), 1);
  }
  $output .= theme('pager', NULL, variable_get('default_nodes_main', 10), 0);
  return $output;
}

/**
 * Implementation of hook_nodeapi().
 */
function taxonomy_nodeapi($node, $op, $arg = 0) {
  switch ($op) {
    case 'insert':
      taxonomy_node_save($node->nid, $node->taxonomy);
      break;
    case 'update':
      taxonomy_node_save($node->nid, $node->taxonomy);
      break;
    case 'delete':
      taxonomy_node_delete($node->nid);
      break;
  }
}

/**
 * Menu callback; displays all nodes associated with a term.
 */
function taxonomy_term_page($str_tids = '', $depth = 0, $op = 'page') {
  if (preg_match('/^([0-9]+[+ ])+[0-9]+$/', $str_tids)) {
    $operator = 'or';
    // The '+' character in a query string may be parsed as ' '.
    $tids = preg_split('/[+ ]/', $str_tids);
  }
  else if (preg_match('/^([0-9]+,)*[0-9]+$/', $str_tids)) {
    $operator = 'and';
    $tids = explode(',', $str_tids);
  }
  else {
    drupal_not_found();
  }

  // Build title:
  $result = db_query('SELECT name FROM {term_data} WHERE tid IN (%s)', implode(',', $tids));
  $names = array();
  while ($term = db_fetch_object($result)) {
    $names[] = $term->name;
  }
  $title = implode(', ', $names);

  switch ($op) {
    case 'page':
      // Build breadcrumb based on first hierarchy of first term:
      $current->tid = $tids[0];
      $breadcrumbs = array(array('path' => $_GET['q']));
      while ($parents = taxonomy_get_parents($current->tid)) {
        $current = array_shift($parents);
        $breadcrumbs[] = array('path' => 'taxonomy/term/'. $current->tid, 'title' => $current->name);
      }
      $breadcrumbs = array_reverse($breadcrumbs);
      menu_set_location($breadcrumbs);

      drupal_set_html_head('<link rel="alternate" type="application/rss+xml" title="RSS - '. $title .'" href="'. url('taxonomy/term/'. $str_tids .'/'. $depth .'/feed') .'" />');

      $output = taxonomy_render_nodes(taxonomy_select_nodes($tids, $operator, $depth, TRUE));
      print theme('page', $output, $title);
      break;

    case 'feed':
      $term = taxonomy_get_term($tids[0]);
      $channel['link'] = url('taxonomy/term/'. $str_tids .'/'. $depth, NULL, NULL, TRUE);
      $channel['title'] = variable_get('site_name', 'drupal') .' - '. $title;
      $channel['description'] = $term->description;

      $result = taxonomy_select_nodes($tids, $operator, $depth, FALSE);
      node_feed($result, $channel);
      break;

    default:
      drupal_not_found();
  }
}

/**
 * Menu callback; dispatches to the proper taxonomy administration function.
 */
function taxonomy_admin() {
  $op = $_POST['op'];
  $edit = $_POST['edit'];

  if (empty($op)) {
    $op = arg(2);
  }

  switch ($op) {
    case 'add':
      if (arg(3) == 'vocabulary') {
        $output = taxonomy_form_vocabulary();
      }