ChangeTracker.php

<?php

namespace NetteExtras\Forms;


class ChangeTracker extends \Nette\Forms\HiddenField
{
	private $session;
	
	private $modifiedValues;
	
	public function __construct($forcedValue = NULL)
	{
		parent::__construct($forcedValue);
		
		$this->monitor('Nette\Application\Presenter');
	}
	
	
	protected function attached($object)
	{
		parent::attached($object);
		if ($object instanceof \Nette\Forms\Form) {
			if ($this->value == NULL) {
				$this->value = base_convert(md5(uniqid(mt_rand(), TRUE)), 16, 36);
			}
		}
		
		if ($object instanceof \Nette\Application\Presenter) {
			if (!$this->isDisabled() && $this->form->isAnchored() && $this->form->isSubmitted()) {
				$this->loadHttpData();
			}
			
			if ($this->value === NULL) {
				throw new \InvalidStateException('At this point, this component should always have a value, but there is a design flaw hidden somewhere deep in the logic...');
			}
			$this->session = \Nette\Environment::getSession('NetteExtras.ChangeTracker');
		}
	}
	
	public function getControl()
	{
		$control = parent::getControl();
		
		if (!isset($this->session[$this->value])) {
			$this->session[$this->value] = $this->form->getValues();
		}
		
		return $control;
	}
	
	
	public function getModifiedValues()
	{
		if ($this->modifiedValues === NULL) {
			if ($this->value === NULL) {
				throw new \InvalidStateException('Component has to be attached to an anchored form.');
			}
			$this->modifiedValues = array();
			$this->buildModifiedValues($this->form->getValues(), $this->session[$this->value]);
		}
		
		return $this->modifiedValues;
	}
	
	private function buildModifiedValues($values, $original, $path = array())
	{
		foreach ($values as $key => $value) {
			if (!isset($original[$key])) {
				$this->pushModifiedValue($key, $value, $path);
			} else {
				if (is_array($value)) {
					$this->buildModifiedValues($value, $original[$key], array_merge($path, array($key)));
				} else {
					if ($original[$key] != $value) {
						$this->pushModifiedValue($key, $value, $path);
					}
				}
			}
		}
	}
	
	private function pushModifiedValue($key, $value, array $path)
	{
		$branch = &$this->modifiedValues;
		foreach ($path as $k) {
			if (!isset($branch[$k])) {
				$branch[$k] = array();
			}
			$branch = &$branch[$k];
		}
		
		$branch[$key] = $value;
	}
}