internal void _prepend(FocusScopeNode child)
{
D.assert(child != this);
D.assert(child != this._firstChild);
D.assert(child != this._lastChild);
D.assert(child._parent == null);
D.assert(child._manager == null);
D.assert(child._nextSibling == null);
D.assert(child._previousSibling == null);
D.assert(() => {
var node = this;
while (node._parent != null)
{
node = node._parent;
}
D.assert(node != child);
return(true);
});
child._parent = this;
child._nextSibling = this._firstChild;
if (this._firstChild != null)
{
this._firstChild._previousSibling = child;
}
this._firstChild = child;
this._lastChild = this._lastChild ?? child;
child._updateManager(this._manager);
}
internal void _remove(FocusScopeNode child)
{
D.assert(child._parent == this);
D.assert(child._manager == this._manager);
D.assert(this._debugUltimatePreviousSiblingOf(child, equals: this._firstChild));
D.assert(this._debugUltimateNextSiblingOf(child, equals: this._lastChild));
if (child._previousSibling == null)
{
D.assert(this._firstChild == child);
this._firstChild = child._nextSibling;
}
else
{
child._previousSibling._nextSibling = child._nextSibling;
}
if (child._nextSibling == null)
{
D.assert(this._lastChild == child);
this._lastChild = child._previousSibling;
}
else
{
child._nextSibling._previousSibling = child._previousSibling;
}
child._previousSibling = null;
child._nextSibling = null;
child._parent = null;
child._updateManager(null);
}