feat(management) Add SubNodeColumn attribute

This new column type allows showing attributes values from subnodes.
This means an additional LDAP search is done for each row.

issue #6084

include/management/columns/class_SubNodeColumn.inc

+<?php
+/*
+  This code is part of FusionDirectory (http://www.fusiondirectory.org/)
+
+  Copyright (C) 2017-2020  FusionDirectory
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program 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 General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+*/
+
+/*!
+ * \brief Column showing an attribute from subnodes
+ */
+class SubNodeColumn extends LinkColumn
+{
+  function fillNeededAttributes (array &$attrs)
+  {
+    $attrs['dn'] = 'raw';
+  }
+
+  function fillSearchedAttributes (array &$attrs)
+  {
+  }
+
+  protected function getAttributeValues (ListingEntry $entry): array
+  {
+    global $config;
+
+    if (isset($entry->cache[__CLASS__]['values'])) {
+      return $entry->cache[__CLASS__]['values'];
+    }
+
+    $values = [];
+
+    $attrs = $this->attributes;
+    if (isset($this->templateAttributes) && $entry->isTemplate()) {
+      $attrs = $this->templateAttributes;
+    }
+    if (isset($attrs)) {
+      $ldap = $config->get_ldap_link();
+      $ldap->cd($entry->dn);
+      $ldap->search('(objectClass=*)', $attrs, 'subtree');
+      while ($node = $ldap->fetch(TRUE)) {
+        if ($node['dn'] === $entry->dn) {
+          continue;
+        }
+        foreach ($attrs as $attr) {
+          if (isset($node[$attr])) {
+            for ($i = 0; $i < $node[$attr]['count']; ++$i) {
+              $values[] = $node[$attr][$i];
+            }
+          }
+        }
+      }
+    }
+
+    $entry->cache[__CLASS__]['values'] = $values;
+
+    return $values;
+  }
+}