/// <summary>
/// I decided to not use recursion to avoid stack overflow, what if object graph is too large?
/// </summary>
/// <param name="source"></param>
/// <returns></returns>
private object DeepClone(object source)
{
var state = CloneState.NextBreadcrumb;
var value = source;
var breadcrumbs = new Stack <Breadcrumb>();
Breadcrumb bcb = null;
IChild child = null;
Type type = null;
// to avoid cyclic references, if objects already exists in target tree - use it
var objectMap = new Hashtable();
switch (state)
{
case CloneState.NextChild:
if (bcb.Childs.Length <= bcb.ChildIdx)
{
if (breadcrumbs.Count == 1)
{
return(bcb.TargetObject);
}
else
{
breadcrumbs.Pop();
var mappedValue = objectMap[bcb.SourceObject] = bcb.TargetObject;
bcb = breadcrumbs.Peek();
child = bcb.Childs[bcb.ChildIdx];
child.SetValue(bcb.TargetObject, mappedValue);
bcb.ChildIdx++;
goto case CloneState.NextChild;
}
}
child = bcb.Childs[bcb.ChildIdx];
value = child.GetValue(bcb.SourceObject);
if (value == null || RequiresShallowClone(child, value))
{
child.SetValue(bcb.TargetObject, value);
bcb.ChildIdx++;
goto case CloneState.NextChild;
}
else if (objectMap.ContainsKey(value))
{
child.SetValue(bcb.TargetObject, objectMap[value]);
bcb.ChildIdx++;
goto case CloneState.NextChild;
}
else
{
goto case CloneState.NextBreadcrumb;
}
case CloneState.NextBreadcrumb:
type = value.GetType();
if (type.IsArray)
{
var size = ((Array)value).Length;
bcb = new Breadcrumb
{
Childs = GetArrayItems(size),
TargetObject = Array.CreateInstance(type.GetElementType(), size),
};
}
else if (HasParameterlessConstructor(type))
{
bcb = new Breadcrumb
{
TargetObject = Activator.CreateInstance(type),
Childs = GetObjectChilds(type, value),
};
}
else
{
// ignore
if (bcb != null)
{
child.SetValue(bcb.TargetObject, null);
bcb.ChildIdx++;
goto case CloneState.NextChild;
}
else
{
throw new NotSupportedException(
"cloning type schould have parameterless constructor or be a one-dimensional array");
}
}
bcb.SourceObject = value;
bcb.ChildIdx = 0;
objectMap.Add(value, bcb.TargetObject);
breadcrumbs.Push(bcb);
goto case CloneState.NextChild;
}
return(source);
}