private void Merge(List <IAction> previous, List <IAction> next)
{
if (previous == null)
{
return;
}
for (int i = previous.Count; i-- > 0;)
{
if (next.Count == 0)
{
break;
}
IAction action = previous[i];
IMergeableAction mergeableAction = action as IMergeableAction;
if (mergeableAction == null)
{
continue;
}
IAction mergedAction = mergeableAction.Merge(this, next);
if (mergedAction == null)
{
previous.RemoveAt(i);
}
else if (mergedAction != action)
{
previous[i] = mergedAction;
}
}
previous.AddRange(next);
}
/// <summary>
/// Runs an action and puts it in the undo list.
/// </summary>
/// <param name="action">action to run</param>
public void Run(IAction action)
{
if (action == null)
{
throw new ArgumentNullException("action");
}
bool changed = false;
recursion++;
try
{
switch (state)
{
case UndoRedoManagerState.Idle:
changed = InternalClearRedo();
state = UndoRedoManagerState.ProcessDo;
current.prime = null;
current.list = new List <IAction>();
break;
case UndoRedoManagerState.ProcessDo:
break;
default:
throw new InvalidOperationException();
}
ScopeAction scope = action as ScopeAction;
if (action.Run(this, ActionType.Do))
{
IAction item = action;
Merge(current.list, ref item);
if ((item != null) && !IsSecondary(item))
{
if ((current.prime == null) || (recursion == 1) && (scope == null))
{
current.prime = item;
}
}
}
if (recursion != 1)
{
return;
}
if (current.prime == null)
{
// There is no prime action.
// We can cancel whole action.
UndoCurrent();
return;
}
bool hasPrimary = false;
for (int i = 0, c = current.list.Count; i < c; i++)
{
IAction item = current.list[i];
if ((current.prime != item) && !IsSecondary(item))
{
hasPrimary = true;
break;
}
}
// End of scope.
if (!hasPrimary && (scope != null))
{
UndoCurrent();
return;
}
changed = true;
bool addAction = true;
if (!hasPrimary && (actions.Count != 0))
{
// Merge previous action with a new one.
Action previousAction = actions[actions.Count - 1];
IMergeableAction mergeableAction = previousAction.prime as IMergeableAction;
if (mergeableAction != null)
{
IAction mergedAction;
mergeList.Add(current.prime);
try
{
mergedAction = mergeableAction.Merge(this, mergeList);
addAction = mergeList.Count != 0;
int index = current.list.IndexOf(current.prime);
if (addAction)
{
current.prime = mergeList[0];
if (index != -1)
{
current.list[index] = current.prime;
}
}
else
{
current.prime = mergedAction;
current.list.RemoveAt(index);
}
}
finally
{
mergeList.Clear();
}
if (!addAction)
{
if (previousAction.list != null)
{
Merge(previousAction.list, current.list);
current.list = previousAction.list;
}
if (current.prime == null)
{
UndoCurrent();
actions.RemoveAt(actions.Count - 1);
}
else
{
if (current.list.Count < 2)
{
current.list = null;
}
actions[actions.Count - 1] = current;
}
return;
}
}
}
if (addAction)
{
if (current.list.Count < 2)
{
current.list = null;
}
actions.Add(current);
}
}
finally
{
if (--recursion == 0)
{
state = UndoRedoManagerState.Idle;
redoPosition = actions.Count;
if (CheckUndoListSize())
{
changed = true;
}
if (changed)
{
OnChanged();
}
}
}
}
