/// <summary>
/// Detects an UndoState change as either an undo or redo operation
/// A positive return value indicates a redo operation, a negative an undo operation;
/// If it is 0, then the adressed stack (undo/redo) was empty
/// The absolute value is the number of records that were adressed, means the size of the group
/// It is possible that the group size changed due to an anomaly, so count of records added by the anomaly is put into addedRecordsCount
/// </summary>
private static int DetectStateChange (UndoState prevState, UndoState nextState, out int addedRecordsCount)
{
addedRecordsCount = 0;
int prevUndoCount = prevState.undoRecords.Count, prevRedoCount = prevState.redoRecords.Count;
int nextUndoCount = nextState.undoRecords.Count, nextRedoCount = nextState.redoRecords.Count;
int undoChange = nextUndoCount-prevUndoCount, redoChange = nextRedoCount-prevRedoCount;
// Check if the action is undo or redo
bool undoAction = undoChange < 0, redoAction = redoChange < 0;
if ((!redoAction && prevUndoCount == 0) || (!undoAction && prevRedoCount == 0)) // Tried to undo/redo with an empty record stack
return 0;
if (!undoAction && !redoAction)
throw new Exception ("Detected neither redo nor undo operation!");
int recordChange = undoAction? Math.Abs (undoChange) : Math.Abs (redoChange);
#if UNDO_DEBUG
Debug.Log ("Detected " + (undoAction? "UNDO" : "REDO") + " of " + recordChange + " initial records!");
#endif
if (redoChange != -undoChange)
{ // This anomaly happens only for records that trigger other undo/redo operations
// -> only known case: Reparent unselected object in hierarchy, each iteration (undo/redo) of the issued record a 'Parenting' record gets added ontop
addedRecordsCount = undoAction? (Math.Abs (redoChange)-Math.Abs (undoChange)) : (Math.Abs (undoChange)-Math.Abs (redoChange));
#if UNDO_DEBUG
Debug.LogWarning ("Due to an anomaly a difference of " + addedRecordsCount + " records was created during " + (undoAction? "undo" : "redo") +
" where undo change was " + undoChange + " and redo change " + redoChange);
#endif
}
return (undoAction? -recordChange : recordChange); // Return the count of initially changed records
}
private static UndoState FetchUndoState()
{
UndoState newUndoState = new UndoState();
getRecordsInternalDelegate.Invoke(newUndoState.undoRecords, newUndoState.redoRecords);
return(newUndoState);
}
/// <summary>
/// Callback recognising the type of record, calling the apropriate callback and handling undo pro records
/// </summary>
private static void UndoRedoPerformed()
{
lastFrameUndoRedoPerformed = true;
AssureRecords();
// Get new UndoState
UndoState prevState = records.undoState;
UndoState newState = records.undoState = FetchUndoState();
// Detect undo/redo
int addedRecordCount;
int change = DetectStateChange(prevState, newState, out addedRecordCount);
if (change == 0) // Nothing happend; Only possible if Undo/Redo stack was empty
{
return;
}
List <UndoProRecord> operatedRecords = records.PerformOperationInternal(change, addedRecordCount);
if (change < 0)
{ // UNDO operation
foreach (UndoProRecord undoRecord in operatedRecords)
{ // Invoke undo operations
if (undoRecord.undo != null)
{
undoRecord.undo.Invoke();
}
}
// Callback for whole group
if (OnUndoPerformed != null)
{
OnUndoPerformed.Invoke(operatedRecords.Select((UndoProRecord record) => record.label).ToArray());
}
}
else
{ // REDO operation
foreach (UndoProRecord redoRecord in operatedRecords)
{ // Invoke redo operations
if (redoRecord.perform != null)
{
redoRecord.perform.Invoke();
}
}
// Callback for whole group
if (OnRedoPerformed != null)
{
OnRedoPerformed.Invoke(operatedRecords.Select((UndoProRecord record) => record.label).ToArray());
}
}
}
/// <summary>
/// Check the current undoState for any added undo records and updates the internal records accordingly
/// </summary>
private static void UpdateUndoRecords ()
{
AssureRecords ();
// Get new UndoState
UndoState prevState = records.undoState;
records.undoState = FetchUndoState ();
UndoState newState = records.undoState;
// Detect additions to the record through comparision of the old and the new UndoState
if (prevState.undoRecords.Count == newState.undoRecords.Count)
return; // No undo record was added for sure
// Fetch new undo records
int addedUndoCount = newState.undoRecords.Count-prevState.undoRecords.Count;
#if UNDO_DEBUG
Debug.Log ("Checking for update... change detected! Added Undo's: " + addedUndoCount);
#endif
if (addedUndoCount < 0)
{ // This happens only when the undo was erased, for example after switching the scene
if (newState.undoRecords.Count != 0)
{
records.ClearRedo ();
Debug.LogWarning ("Cleared Redo because some undos were removed!");
}
CreateRecords ();
return;
}
// Update internals
records.UndoRecordsAdded (addedUndoCount);
// Callback
string[] undosAdded = newState.undoRecords.GetRange (newState.undoRecords.Count-addedUndoCount, addedUndoCount).ToArray ();
if (OnAddUndoRecord != null)
OnAddUndoRecord.Invoke (undosAdded, newState.redoRecords.Count == 0);
#if UNDO_DEBUG
// Debug added undo records
string undoLog = undosAdded.Length + " undo records added: ";
for (int undoCnt = 0; undoCnt < undosAdded.Length; undoCnt++)
undoLog += undosAdded[undoCnt] + "; ";
Debug.Log (undoLog);
#endif
}