/**
* Inserts the item
* @param mixed $item
* @param mixed $parent
* @param mixed $previous
*/
function Insert($item, $parent = null, $previous = null)
{
if ($previous) {
$parent = $this->provider->ParentOf($previous);
}
$oldNext = $this->provider->NextOf($item);
$oldPrev = $this->provider->PreviousOf($item);
$oldFirst = $this->provider->FirstChildOf($parent);
if (!($oldPrev && $previous && $this->provider->Equals($oldPrev, $previous))) {
$this->CloseCutGap($oldPrev, $oldNext, $item);
}
$this->UpdateInsertItem($item, $parent, $previous);
if (!$previous) {
$this->AssureFirstChild($item, $oldFirst);
}
}
