Source code for pyface.undo.undo_manager

# (C) Copyright 2008-2022 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!

# ------------------------------------------------------------------------------
# Copyright (c) 2008, Riverbank Computing Limited
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in enthought/LICENSE.txt and may be redistributed only
# under the conditions described in the aforementioned license.  The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
# Thanks for using Enthought open source!
#
# Author: Riverbank Computing Limited
# Description: <Enthought undo package component>
# ------------------------------------------------------------------------------

# Enthought library imports.
from traits.api import (
    Bool,
    Event,
    HasTraits,
    Instance,
    Int,
    Property,
    Str,
    provides,
    observe,
)

# Local imports.
from .i_undo_manager import IUndoManager


[docs]@provides(IUndoManager) class UndoManager(HasTraits): """The UndoManager class is the default implementation of the IUndoManager interface. """ #### 'IUndoManager' interface ############################################# #: This is the currently active command stack and may be None. Typically it #: is set when some sort of editor becomes active. active_stack = Instance("pyface.undo.api.ICommandStack") #: This reflects the clean state of the currently active command stack. It #: is intended to support a "document modified" indicator in the GUI. It is #: maintained by the undo manager. active_stack_clean = Property(Bool) #: This is the name of the command that can be redone. It will be empty if #: there is no command that can be redone. It is maintained by the undo #: manager. redo_name = Property(Str) #: This is the sequence number of the next command to be performed. It is #: incremented immediately before a command is invoked (by its 'do()' #: method). sequence_nr = Int() #: This event is fired when the index of a command stack changes. The value #: of the event is the stack that has changed. Note that it may not be the #: active stack. stack_updated = Event() #: This is the name of the command that can be undone. It will be empty if #: there is no command that can be undone. It is maintained by the undo #: manager. undo_name = Property(Str) ########################################################################### # 'IUndoManager' interface. ###########################################################################
[docs] def redo(self): """ Redo the last undone command of the active command stack. """ if self.active_stack is not None: self.active_stack.redo()
[docs] def undo(self): """ Undo the last command of the active command stack. """ if self.active_stack is not None: self.active_stack.undo()
########################################################################### # Private interface. ########################################################################### @observe("active_stack") def _update_stack_updated(self, event): """ Handle a different stack becoming active. """ new = event.new # Pretend that the stack contents have changed. self.stack_updated = new def _get_active_stack_clean(self): """ Get the current clean state. """ if self.active_stack is None: active_stack_clean = True else: active_stack_clean = self.active_stack.clean return active_stack_clean def _get_redo_name(self): """ Get the current redo name. """ if self.active_stack is None: redo_name = "" else: redo_name = self.active_stack.redo_name return redo_name def _get_undo_name(self): """ Get the current undo name. """ if self.active_stack is None: undo_name = "" else: undo_name = self.active_stack.undo_name return undo_name