118 lines
No EOL
3.9 KiB
PHP
118 lines
No EOL
3.9 KiB
PHP
<?php
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/*
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* Copyright (c) 2010 by Justin Otherguy <justin@justinotherguy.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License (either version 2 or
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* version 3) as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* For more information on the GPL, please go to:
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* http://www.gnu.org/copyleft/gpl.html
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*/
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/*
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* DatabaseObject which is structured by nested sets
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* @url // TODO add url
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*/
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abstract class NestedDatabaseObject extends DatabaseObject {
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public function __set($key, $value) {
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if ($key == 'left' || $key == 'right') {
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throw new NestedDatabaseException('nested set fields are read only! please make use of move() or delete() instead');
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}
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parent::__set($key, $value);
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}
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public function addChild(NestedDatabaseObject $child) {
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if (isset($child->id)) {
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throw new NestedDatabaseException('Object is already part of the tree');
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}
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// TODO start transaction
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$this->dbh->execute('UPDATE ' . static::table . ' SET left = left + 2 WHERE left > ' . $this->right);
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$this->dbh->execute('UPDATE ' . static::table . ' SET right = right + 2 WHERE right >= ' . $this->right);
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$child->left = $this->right;
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$child->right = $this->right + 1;
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$this->right += 2;
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$child->insert();
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}
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public function getChilds() {
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$sql = 'SELECT * FROM ' . static::table . ' WHERE left > ' . $this->left . ' && left < ' . $this->right;
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$result = $this->dbh->query($sql);
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$objs = array();
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foreach ($result as $obj) {
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$objs[$obj['id']] = static::factory($obj);
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}
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return $groups;
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}
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/*
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* deletes subset under $this
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*/
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public function delete() {
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$move = floor(($this->right - $this->left) / 2);
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$move = 2 * (1 + $move);
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// TODO start transaction
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// delete nodes
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$result = $this->dbh->query('SELECT * FROM ' . static::table . ' WHERE left >= ' . $this->left . ' && left <= ' . $this->right);
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foreach ($result as $obj) {
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$obj->delete(); // TODO optimize (all in one query)
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}
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// move remaining nodes ...
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$this->dbh->execute('UPDATE ' . static::table . ' SET left = left - ' . $move . ' WHERE left > ' . $this->right);
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$this->dbh->execute('UPDATE ' . static::table . ' SET right = right - ' . $move . ' WHERE right > ' . $this->right);
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}
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/*
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* checks if $child is a child of $this
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* @return bool
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*/
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public function contains(NestedDatabaseObject $child) { // TODO untested
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$sql = 'SELECT * FROM ' . static::table . ' WHERE left > ' . $this->left . ' && left < ' . $this->right . ' && id = ' . $child->id;
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$result = $this->dbh->query($sql);
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return ($result->count() > 0) ? true : false;
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}
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public function moveTo(NestedDatabaseObject $destination) { // TODO implement
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// $this->getChilds
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$obj = $this->getChilds();
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foreach ($objs as $obj) {
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$obj->right += $destination->left - $this->left;
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$obj->left = $destination->left;
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}
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// close whole
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$move = floor(($this->right - $this->left) / 2);
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$move = 2 * (1 + $move);
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$this->dbh->execute('UPDATE ' . static::table . ' SET left = left - ' . $move . ' WHERE left > ' . $this->right);
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$this->dbh->execute('UPDATE ' . static::table . ' SET right = right - ' . $move . ' WHERE right > ' . $this->right);
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// create hole
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$this->dbh->execute('UPDATE ' . static::table . ' SET left = left + ' . $move . ' WHERE left > ' . $this->right);
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$this->dbh->execute('UPDATE ' . static::table . ' SET right = right + ' . $move . ' WHERE right >= ' . $this->right);
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}
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}
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class NestedDatabaseException extends Exception {}
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?>
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