2 files changed, 714 insertions, 0 deletions
diff --git a/phpBB/includes/nestedset/base.php b/phpBB/includes/nestedset/base.php
new file mode 100644
index 0000000000..7f4691b7e0
--- /dev/null
+++ b/phpBB/includes/nestedset/base.php
@@ -0,0 +1,632 @@
+<?php
+/**
+*
+* @package Nested Set
+* @copyright (c) 2013 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*
+*/
+
+/**
+* @ignore
+*/
+if (!defined('IN_PHPBB'))
+{
+	exit;
+}
+
+abstract class phpbb_nestedset_base implements phpbb_nestedset_interface
+{
+	/** @var phpbb_db_driver*/
+	protected $db;
+
+	/** @var String */
+	protected $table_name;
+
+	/** @var String */
+	protected $item_class = 'phpbb_nestedset_item_base';
+
+	/**
+	* Column names in the table
+	* @var array
+	*/
+	protected $table_columns = array(
+		'item_id'	=> 'item_id',
+		'left_id'	=> 'left_id',
+		'right_id'	=> 'right_id',
+		'parent_id'	=> 'parent_id',
+		'item_parents'	=> 'item_parents',
+	);
+
+	/**
+	* Additional SQL restrictions
+	* Allows to have multiple nested sets in one table
+	* @var String
+	*/
+	protected $sql_where = '';
+
+	/**
+	* List of item properties to be cached in $item_parents
+	* @var array
+	*/
+	protected $item_basic_data = array('*');
+
+	/**
+	* Delete an item from the nested set (also deletes the rows form the table)
+	*
+	* Also deletes all subitems from the nested set
+	*
+	* @param string		$operator		SQL operator that needs to be prepended to sql_where,
+	*									if it is not empty.
+	* @param string		$column_prefix	Prefix that needs to be prepended to column names
+	* @return bool True if the item was deleted
+	*/
+	public function get_sql_where($operator = 'AND', $column_prefix = '')
+	{
+		return (!$this->sql_where) ? '' : $operator . ' ' . sprintf($this->sql_where, $column_prefix);
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function insert(array $additional_data)
+	{
+		$item_data = array_merge($additional_data, array(
+			$this->table_columns['parent_id']		=> 0,
+			$this->table_columns['left_id']			=> 0,
+			$this->table_columns['right_id']		=> 0,
+			$this->table_columns['item_parents']	=> '',
+		));
+
+		unset($item_data[$this->table_columns['item_id']]);
+
+		$sql = 'INSERT INTO ' . $this->table_name . ' ' . $this->db->sql_build_array('INSERT', $item_data);
+		$this->db->sql_query($sql);
+
+		$item_data[$this->table_columns['item_id']] = (int) $this->db->sql_nextid();
+
+		$item = new $this->item_class($item_data);
+
+		return array_merge($item_data, $this->add($item));
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function add(phpbb_nestedset_item_interface $item)
+	{
+		$sql = 'SELECT MAX(' . $this->table_columns['right_id'] . ') AS ' . $this->table_columns['right_id'] . '
+			FROM ' . $this->table_name . '
+			' . $this->get_sql_where('WHERE');
+		$result = $this->db->sql_query($sql);
+		$current_max_right_id = (int) $this->db->sql_fetchfield($this->table_columns['right_id']);
+		$this->db->sql_freeresult($result);
+
+		$update_item_data = array(
+			$this->table_columns['parent_id']		=> 0,
+			$this->table_columns['left_id']			=> $current_max_right_id + 1,
+			$this->table_columns['right_id']		=> $current_max_right_id + 2,
+			$this->table_columns['item_parents']	=> '',
+		);
+
+		$sql = 'UPDATE ' . $this->table_name . '
+			SET ' . $this->db->sql_build_array('UPDATE', $update_item_data) . '
+			WHERE ' . $this->table_columns['item_id'] . ' = ' . $item->get_item_id();
+		$this->db->sql_query($sql);
+
+		return $update_item_data;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function remove(phpbb_nestedset_item_interface $item)
+	{
+		if ($item->has_children())
+		{
+			$items = array_keys($this->get_branch_data($item, 'children'));
+		}
+		else
+		{
+			$items = array($item->get_item_id());
+		}
+
+		$this->remove_subset($items, $item);
+
+		return $items;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function delete(phpbb_nestedset_item_interface $item)
+	{
+		$removed_items = $this->remove($item);
+
+		$sql = 'DELETE FROM ' . $this->table_name . '
+			WHERE ' . $this->db->sql_in_set($this->table_columns['item_id'], $removed_items) . '
+			' . $this->get_sql_where('AND');
+		$this->db->sql_query($sql);
+
+		return $removed_items;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function move(phpbb_nestedset_item_interface $item, $delta)
+	{
+		if ($delta == 0)
+		{
+			return false;
+		}
+
+		$action = ($delta > 0) ? 'move_up' : 'move_down';
+		$delta = abs($delta);
+
+		/**
+		* Fetch all the siblings between the item's current spot
+		* and where we want to move it to. If there are less than $delta
+		* siblings between the current spot and the target then the
+		* item will move as far as possible
+		*/
+		$sql = 'SELECT ' . implode(', ', $this->table_columns) . '
+			FROM ' . $this->table_name . '
+			WHERE ' . $this->table_columns['parent_id'] . ' = ' . $item->get_parent_id() . '
+				' . $this->get_sql_where() . '
+				AND ';
+
+		if ($action == 'move_up')
+		{
+			$sql .= $this->table_columns['right_id'] . ' < ' . $item->get_right_id() . ' ORDER BY ' . $this->table_columns['right_id'] . ' DESC';
+		}
+		else
+		{
+			$sql .= $this->table_columns['left_id'] . ' > ' . $item->get_left_id() . ' ORDER BY ' . $this->table_columns['left_id'] . ' ASC';
+		}
+
+		$result = $this->db->sql_query_limit($sql, $delta);
+
+		$target = null;
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			$target = new $this->item_class($row);
+		}
+		$this->db->sql_freeresult($result);
+
+		if (is_null($target))
+		{
+			// The item is already on top or bottom
+			return false;
+		}
+
+		/**
+		* $left_id and $right_id define the scope of the items that are affected by the move.
+		* $diff_up and $diff_down are the values to substract or add to each item's left_id
+		* and right_id in order to move them up or down.
+		* $move_up_left and $move_up_right define the scope of the items that are moving
+		* up. Other items in the scope of ($left_id, $right_id) are considered to move down.
+		*/
+		if ($action == 'move_up')
+		{
+			$left_id = $target->get_left_id();
+			$right_id = $item->get_right_id();
+
+			$diff_up = $item->get_left_id() - $target->get_left_id();
+			$diff_down = $item->get_right_id() + 1 - $item->get_left_id();
+
+			$move_up_left = $item->get_left_id();
+			$move_up_right = $item->get_right_id();
+		}
+		else
+		{
+			$left_id = $item->get_left_id();
+			$right_id = $target->get_right_id();
+
+			$diff_up = $item->get_right_id() + 1 - $item->get_left_id();
+			$diff_down = $target->get_right_id() - $item->get_right_id();
+
+			$move_up_left = $item->get_right_id() + 1;
+			$move_up_right = $target->get_right_id();
+		}
+
+		// Now do the dirty job
+		$sql = 'UPDATE ' . $this->table_name . '
+			SET ' . $this->table_columns['left_id'] . ' = ' . $this->table_columns['left_id'] . ' + CASE
+				WHEN ' . $this->table_columns['left_id'] . " BETWEEN {$move_up_left} AND {$move_up_right} THEN -{$diff_up}
+				ELSE {$diff_down}
+			END,
+			" . $this->table_columns['right_id'] . ' = ' . $this->table_columns['right_id'] . ' + CASE
+				WHEN ' . $this->table_columns['right_id'] . " BETWEEN {$move_up_left} AND {$move_up_right} THEN -{$diff_up}
+				ELSE {$diff_down}
+			END,
+			" . $this->table_columns['item_parents'] . " = ''
+			WHERE
+				" . $this->table_columns['left_id'] . " BETWEEN {$left_id} AND {$right_id}
+				AND " . $this->table_columns['right_id'] . " BETWEEN {$left_id} AND {$right_id}
+				" . $this->get_sql_where();
+		$this->db->sql_query($sql);
+
+		return true;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function move_down(phpbb_nestedset_item_interface $item)
+	{
+		return $this->move($item, -1);
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function move_up(phpbb_nestedset_item_interface $item)
+	{
+		return $this->move($item, 1);
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function move_children(phpbb_nestedset_item_interface $current_parent, phpbb_nestedset_item_interface $new_parent)
+	{
+		if (!$current_parent->has_children() || !$current_parent->get_item_id() || $current_parent->get_item_id() == $new_parent->get_item_id())
+		{
+			return false;
+		}
+
+		$move_items = array_keys($this->get_branch_data($current_parent, 'children', true, false));
+
+		if (in_array($new_parent->get_item_id(), $move_items))
+		{
+			throw new phpbb_nestedset_exception('INVALID_PARENT');
+		}
+
+		$diff = sizeof($move_items) * 2;
+		$sql_exclude_moved_items = $this->db->sql_in_set($this->table_columns['item_id'], $move_items, true);
+
+		$this->db->sql_transaction('begin');
+
+		$this->remove_subset($move_items, $current_parent, false);
+
+		if ($new_parent->get_item_id())
+		{
+			// Retrieve new-parent again, it may have been changed...
+			$sql = 'SELECT *
+				FROM ' . $this->table_name . '
+				WHERE ' . $this->table_columns['item_id'] . ' = ' . $new_parent->get_item_id();
+			$result = $this->db->sql_query($sql);
+			$parent_data = $this->db->sql_fetchrow($result);
+			$this->db->sql_freeresult($result);
+
+			if (!$parent_data)
+			{
+				$this->db->sql_transaction('rollback');
+				throw new phpbb_nestedset_exception('INVALID_PARENT');
+			}
+
+			$new_parent = new $this->item_class($parent_data);
+
+			$new_right_id = $this->prepare_adding_subset($move_items, $new_parent);
+
+			if ($new_right_id > $current_parent->get_right_id())
+			{
+				$diff = ' + ' . ($new_right_id - $current_parent->get_right_id());
+			}
+			else
+			{
+				$diff = ' - ' . abs($new_right_id - $current_parent->get_right_id());
+			}
+		}
+		else
+		{
+			$sql = 'SELECT MAX(' . $this->table_columns['right_id'] . ') AS ' . $this->table_columns['right_id'] . '
+				FROM ' . $this->table_name . '
+				WHERE ' . $sql_exclude_moved_items . '
+					' . $this->get_sql_where('AND');
+			$result = $this->db->sql_query($sql);
+			$row = $this->db->sql_fetchrow($result);
+			$this->db->sql_freeresult($result);
+
+			$diff = ' + ' . ($row[$this->table_columns['right_id']] - $current_parent->get_left_id());
+		}
+
+		$sql = 'UPDATE ' . $this->table_name . '
+			SET ' . $this->table_columns['left_id'] . ' = ' . $this->table_columns['left_id'] . $diff . ',
+				' . $this->table_columns['right_id'] . ' = ' . $this->table_columns['right_id'] . $diff . ',
+				' . $this->table_columns['parent_id'] . ' = ' . $this->db->sql_case($this->table_columns['parent_id'] . ' = ' . $current_parent->get_item_id(), $new_parent->get_item_id(), $this->table_columns['parent_id']) . ',
+				' . $this->table_columns['item_parents'] . " = ''
+			WHERE " . $this->db->sql_in_set($this->table_columns['item_id'], $move_items) . '
+				' . $this->get_sql_where('AND');
+		$this->db->sql_query($sql);
+
+		$this->db->sql_transaction('commit');
+
+		return true;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function set_parent(phpbb_nestedset_item_interface $item, phpbb_nestedset_item_interface $new_parent)
+	{
+		$move_items = array_keys($this->get_branch_data($item, 'children'));
+
+		if (in_array($new_parent->get_item_id(), $move_items))
+		{
+			throw new phpbb_nestedset_exception('INVALID_PARENT');
+		}
+
+		$diff = sizeof($move_items) * 2;
+		$sql_exclude_moved_items = $this->db->sql_in_set($this->table_columns['item_id'], $move_items, true);
+
+		$this->db->sql_transaction('begin');
+
+		$this->remove_subset($move_items, $item, false);
+
+		if ($new_parent->get_item_id())
+		{
+			// Retrieve new-parent again, it may have been changed...
+			$sql = 'SELECT *
+				FROM ' . $this->table_name . '
+				WHERE ' . $this->table_columns['item_id'] . ' = ' . $new_parent->get_item_id();
+			$result = $this->db->sql_query($sql);
+			$parent_data = $this->db->sql_fetchrow($result);
+			$this->db->sql_freeresult($result);
+
+			if (!$parent_data)
+			{
+				$this->db->sql_transaction('rollback');
+				throw new phpbb_nestedset_exception('INVALID_PARENT');
+			}
+
+			$new_parent = new $this->item_class($parent_data);
+
+			$new_right_id = $this->prepare_adding_subset($move_items, $new_parent);
+
+			if ($new_right_id > $item->get_right_id())
+			{
+				$diff = ' + ' . ($new_right_id - $item->get_right_id() - 1);
+			}
+			else
+			{
+				$diff = ' - ' . abs($new_right_id - $item->get_right_id() - 1);
+			}
+		}
+		else
+		{
+			$sql = 'SELECT MAX(' . $this->table_columns['right_id'] . ') AS ' . $this->table_columns['right_id'] . '
+				FROM ' . $this->table_name . '
+				WHERE ' . $sql_exclude_moved_items . '
+					' . $this->get_sql_where('AND');
+			$result = $this->db->sql_query($sql);
+			$row = $this->db->sql_fetchrow($result);
+			$this->db->sql_freeresult($result);
+
+			$diff = ' + ' . ($row[$this->table_columns['right_id']] - $item->get_left_id() + 1);
+		}
+
+		$sql = 'UPDATE ' . $this->table_name . '
+			SET ' . $this->table_columns['left_id'] . ' = ' . $this->table_columns['left_id'] . $diff . ',
+				' . $this->table_columns['right_id'] . ' = ' . $this->table_columns['right_id'] . $diff . ',
+				' . $this->table_columns['parent_id'] . ' = ' . $this->db->sql_case($this->table_columns['item_id'] . ' = ' . $item->get_item_id(), $new_parent->get_item_id(), $this->table_columns['parent_id']) . ',
+				' . $this->table_columns['item_parents'] . " = ''
+			WHERE " . $this->db->sql_in_set($this->table_columns['item_id'], $move_items) . '
+				' . $this->get_sql_where('AND');
+		$this->db->sql_query($sql);
+
+		$this->db->sql_transaction('commit');
+
+		return true;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function get_branch_data(phpbb_nestedset_item_interface $item, $type = 'all', $order_desc = true, $include_item = true)
+	{
+		switch ($type)
+		{
+			case 'parents':
+				$condition = 'i1.' . $this->table_columns['left_id'] . ' BETWEEN i2.' . $this->table_columns['left_id'] . ' AND i2.' . $this->table_columns['right_id'] . '';
+			break;
+
+			case 'children':
+				$condition = 'i2.' . $this->table_columns['left_id'] . ' BETWEEN i1.' . $this->table_columns['left_id'] . ' AND i1.' . $this->table_columns['right_id'] . '';
+			break;
+
+			default:
+				$condition = 'i2.' . $this->table_columns['left_id'] . ' BETWEEN i1.' . $this->table_columns['left_id'] . ' AND i1.' . $this->table_columns['right_id'] . '
+					OR i1.' . $this->table_columns['left_id'] . ' BETWEEN i2.' . $this->table_columns['left_id'] . ' AND i2.' . $this->table_columns['right_id'];
+			break;
+		}
+
+		$rows = array();
+
+		$sql = 'SELECT i2.*
+			FROM ' . $this->table_name . ' i1
+			LEFT JOIN ' . $this->table_name . " i2
+				ON (($condition) " . $this->get_sql_where('AND', 'i2.') . ')
+			WHERE i1.' . $this->table_columns['item_id'] . ' = ' . $item->get_item_id() . '
+				' . $this->get_sql_where('AND', 'i1.') . '
+			ORDER BY i2.' . $this->table_columns['left_id'] . ' ' . ($order_desc ? 'ASC' : 'DESC');
+		$result = $this->db->sql_query($sql);
+
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			if (!$include_item && $item->get_item_id() === (int) $row[$this->table_columns['item_id']])
+			{
+				continue;
+			}
+
+			$rows[$row[$this->table_columns['item_id']]] = $row;
+		}
+		$this->db->sql_freeresult($result);
+
+		return $rows;
+	}
+
+	/**
+	* Get base information of parent items
+	*
+	* Data is cached in the item_parents column in the item table
+	*
+	* @inheritdoc
+	*/
+	public function get_parent_data(phpbb_nestedset_item_interface $item)
+	{
+		$parents = array();
+		if ($item->get_parent_id())
+		{
+			if (!$item->get_item_parents_data())
+			{
+				$sql = 'SELECT ' . implode(', ', $this->item_basic_data) . '
+					FROM ' . $this->table_name . '
+					WHERE ' . $this->table_columns['left_id'] . ' < ' . $item->get_left_id() . '
+						AND ' . $this->table_columns['right_id'] . ' > ' . $item->get_right_id() . '
+						' . $this->get_sql_where('AND') . '
+					ORDER BY ' . $this->table_columns['left_id'] . ' ASC';
+				$result = $this->db->sql_query($sql);
+
+				while ($row = $this->db->sql_fetchrow($result))
+				{
+					$parents[$row[$this->table_columns['item_id']]] = $row;
+				}
+				$this->db->sql_freeresult($result);
+
+				$item_parents = serialize($parents);
+
+				$sql = 'UPDATE ' . $this->table_name . '
+					SET ' . $this->table_columns['item_parents'] . " = '" . $this->db->sql_escape($item_parents) . "'
+					WHERE " . $this->table_columns['parent_id'] . ' = ' . $item->get_parent_id();
+				$this->db->sql_query($sql);
+			}
+			else
+			{
+				$parents = unserialize($item->get_item_parents_data());
+			}
+		}
+
+		return $parents;
+	}
+
+	/**
+	* Remove a subset from the nested set
+	*
+	* @param array	$subset_items		Subset of items to remove
+	* @param phpbb_nestedset_item_interface	$bounding_item	Item containing the right bound of the subset
+	* @param bool	$set_subset_zero	Should the parent, left and right id of the item be set to 0, or kept unchanged?
+	* @return	null
+	*/
+	protected function remove_subset(array $subset_items, phpbb_nestedset_item_interface $bounding_item, $set_subset_zero = true)
+	{
+		$diff = sizeof($subset_items) * 2;
+		$sql_subset_items = $this->db->sql_in_set($this->table_columns['item_id'], $subset_items);
+		$sql_not_subset_items = $this->db->sql_in_set($this->table_columns['item_id'], $subset_items, true);
+
+		$sql_is_parent = $this->table_columns['left_id'] . ' <= ' . $bounding_item->get_right_id() . '
+			AND ' . $this->table_columns['right_id'] . ' >= ' . $bounding_item->get_right_id();
+
+		$sql_is_right = $this->table_columns['left_id'] . ' > ' . $bounding_item->get_right_id();
+
+		$set_left_id = $this->db->sql_case($sql_is_right, $this->table_columns['left_id'] . ' - ' . $diff, $this->table_columns['left_id']);
+		$set_right_id = $this->db->sql_case($sql_is_parent . ' OR ' . $sql_is_right, $this->table_columns['right_id'] . ' - ' . $diff, $this->table_columns['right_id']);
+
+		if ($set_subset_zero)
+		{
+			$set_left_id = $this->db->sql_case($sql_subset_items, 0, $set_left_id);
+			$set_right_id = $this->db->sql_case($sql_subset_items, 0, $set_right_id);
+		}
+
+		$sql = 'UPDATE ' . $this->table_name . '
+			SET ' . $this->table_columns['left_id'] . ' = ' . $set_left_id . ',
+				' . $this->table_columns['right_id'] . ' = ' . $set_right_id . ',
+				' . (($set_subset_zero) ? $this->table_columns['parent_id'] . ' = ' . $this->db->sql_case($sql_subset_items, 0, $this->table_columns['parent_id']) . ',' : '') . '
+				' . $this->table_columns['item_parents'] . " = ''
+			" . ((!$set_subset_zero) ? ' WHERE ' . $sql_not_subset_items . ' ' . $this->get_sql_where('AND') : $this->get_sql_where('WHERE'));
+		$this->db->sql_query($sql);
+	}
+
+	/**
+	* Add a subset to the nested set
+	*
+	* @param array	$subset_items		Subset of items to add
+	* @param phpbb_nestedset_item_interface	$new_parent	Item containing the right bound of the new parent
+	* @return	int		New right id of the parent item
+	*/
+	protected function prepare_adding_subset(array $subset_items, phpbb_nestedset_item_interface $new_parent)
+	{
+		$diff = sizeof($subset_items) * 2;
+		$sql_not_subset_items = $this->db->sql_in_set($this->table_columns['item_id'], $subset_items, true);
+
+		$set_left_id = $this->db->sql_case($this->table_columns['left_id'] . ' > ' . $new_parent->get_right_id(), $this->table_columns['left_id'] . ' + ' . $diff, $this->table_columns['left_id']);
+		$set_right_id = $this->db->sql_case($this->table_columns['right_id'] . ' >= ' . $new_parent->get_right_id(), $this->table_columns['right_id'] . ' + ' . $diff, $this->table_columns['right_id']);
+
+		$sql = 'UPDATE ' . $this->table_name . '
+			SET ' . $this->table_columns['left_id'] . ' = ' . $set_left_id . ',
+				' . $this->table_columns['right_id'] . ' = ' . $set_right_id . ',
+				' . $this->table_columns['item_parents'] . " = ''
+			WHERE " . $sql_not_subset_items . '
+				' . $this->get_sql_where('AND');
+		$this->db->sql_query($sql);
+
+		return $new_parent->get_right_id() + $diff;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function recalculate_nested_set($new_id, $parent_id = 0, $reset_ids = false)
+	{
+		if ($reset_ids)
+		{
+			$sql = 'UPDATE ' . $this->table_name . '
+				SET ' . $this->db->sql_build_array('UPDATE', array(
+					$this->table_columns['left_id'] => 0,
+					$this->table_columns['right_id'] => 0,
+					$this->table_columns['item_parents'] => '',
+				)) . '
+				' . $this->get_sql_where('WHERE');
+			$this->db->sql_query($sql);
+		}
+
+		$sql = 'SELECT *
+			FROM ' . $this->table_name . '
+			WHERE ' . $this->table_columns['parent_id'] . ' = ' . (int) $parent_id . '
+				' . $this->get_sql_where('AND') . '
+			ORDER BY ' . $this->table_columns['left_id'] . ', ' . $this->table_columns['item_id'] . ' ASC';
+		$result = $this->db->sql_query($sql);
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			// First we update the left_id for this module
+			if ($row[$this->table_columns['left_id']] != $new_id)
+			{
+				$sql = 'UPDATE ' . $this->table_name . '
+					SET ' . $this->db->sql_build_array('UPDATE', array(
+						$this->table_columns['left_id'] => $new_id,
+						$this->table_columns['item_parents'] => '',
+					)) . '
+					WHERE ' . $this->table_columns['item_id'] . ' = ' . $row[$this->table_columns['item_id']];
+				$this->db->sql_query($sql);
+			}
+			$new_id++;
+
+			// Then we go through any children and update their left/right id's
+			$new_id = $this->recalculate_nested_set($new_id, $row[$this->table_columns['item_id']]);
+
+			// Then we come back and update the right_id for this module
+			if ($row[$this->table_columns['right_id']] != $new_id)
+			{
+				$sql = 'UPDATE ' . $this->table_name . '
+					SET ' . $this->db->sql_build_array('UPDATE', array($this->table_columns['right_id'] => $new_id)) . '
+					WHERE ' . $this->table_columns['item_id'] . ' = ' . $row[$this->table_columns['item_id']];
+				$this->db->sql_query($sql);
+			}
+			$new_id++;
+		}
+		$this->db->sql_freeresult($result);
+
+		return $new_id;
+	}
+}
diff --git a/phpBB/includes/nestedset/item/base.php b/phpBB/includes/nestedset/item/base.php
new file mode 100644
index 0000000000..c3a7600827
--- /dev/null
+++ b/phpBB/includes/nestedset/item/base.php
@@ -0,0 +1,82 @@
+<?php
+/**
+*
+* @package Nested Set
+* @copyright (c) 2013 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*
+*/
+
+/**
+* @ignore
+*/
+if (!defined('IN_PHPBB'))
+{
+	exit;
+}
+
+abstract class phpbb_nestedset_item_base implements phpbb_nestedset_item_interface
+{
+	/** @var int */
+	protected $item_id;
+
+	/** @var int */
+	protected $parent_id;
+
+	/** @var string */
+	protected $item_parents_data;
+
+	/** @var int */
+	protected $left_id;
+
+	/** @var int */
+	protected $right_id;
+
+	/**
+	* @inheritdoc
+	*/
+	public function get_item_id()
+	{
+		return (int) $this->item_id;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function get_parent_id()
+	{
+		return (int) $this->parent_id;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function get_item_parents_data()
+	{
+		return (string) $this->item_parents_data;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function get_left_id()
+	{
+		return (int) $this->left_id;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function get_right_id()
+	{
+		return (int) $this->right_id;
+	}
+
+	/**
+	* @inheritdoc
+	*/
+	public function has_children()
+	{
+		return $this->right_id - $this->left_id > 1;
+	}
+}