public IObservable <Unit> Clear()
{
UpdateSubjects(true);
StackRedo.Clear();
StackUndo.Clear();
UpdateSubjects();
return(Observables.Unit);
}
public void Dispose()
{
StackRedo.Clear();
StackUndo.Clear();
_canUndo.Dispose();
_canRedo.Dispose();
_canClear.Dispose();
_canRecord.Dispose();
}
public IObservable <HistoryEntry> Record(HistoryEntry entry, Func <HistoryEntry, IObservable <HistoryEntry> > execute)
{
StackRedo.Clear();
UpdateSubjects(true);
return(execute(entry).Do(updatedEntry =>
{
StackUndo.Push(updatedEntry);
UpdateSubjects();
}));
}
public IObservable <HistoryEntry> Redo(Func <HistoryEntry, IObservable <HistoryEntry> > execute)
{
if (StackRedo.Count == 0)
{
throw new Exception();
}
UpdateSubjects(true);
return(execute(StackRedo.Pop()).Do(entry =>
{
StackUndo.Push(entry);
UpdateSubjects();
}));
}
private void UpdateSubjects(bool disableAll = false)
{
if (disableAll)
{
_canUndo.OnNext(false);
_canRedo.OnNext(false);
_canClear.OnNext(false);
_canRecord.OnNext(false);
}
else
{
var hasUndoEntries = StackUndo.Any();
var hasRedoEntries = StackRedo.Any();
_canUndo.OnNext(hasUndoEntries);
_canRedo.OnNext(hasRedoEntries);
_canClear.OnNext(hasUndoEntries || hasRedoEntries);
_canRecord.OnNext(true);
}
}
