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Contents
# frozen_string_literal: true
# Copyright (C) 2004-2006 Laurent Sansonetti
#
# Alexandria is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of the
# License, or (at your option) any later version.
#
# Alexandria is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public
# License along with Alexandria; see the file COPYING. If not,
# write to the Free Software Foundation, Inc., 51 Franklin Street,
# Fifth Floor, Boston, MA 02110-1301 USA.
module Alexandria
class UndoManager
include Singleton
include Observable
attr_reader :actions
def initialize
@undo_actions = []
@redo_actions = []
@within_undo = @withing_redo = false
end
def push(&block)
(@within_undo ? @redo_actions : @undo_actions) << block
notify
end
def can_undo?
!@undo_actions.empty?
end
def can_redo?
!@redo_actions.empty?
end
def undo!
@within_undo = true
begin
action(@undo_actions)
ensure
@within_undo = false
end
end
def redo!
@within_redo = true
begin
action(@redo_actions)
ensure
@within_redo = false
end
end
private
def action(array)
action = array.pop
raise if action.nil?
action.call
notify
end
def notify
changed
notify_observers(self)
end
end
end
Version data entries
8 entries across 8 versions & 1 rubygems