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# -*- coding: utf-8 -*-
"""
# Simple password manager
# Copyright (c) 2011-2019 Michael Buesch <m@bues.ch>
# Licensed under the GNU/GPL version 2 or later.
"""
__all__ = [
"UndoStack",
]
class UndoCommand(object):
def __init__(self, doCommands, undoCommands):
if isinstance(doCommands, (tuple, list)):
self.doCommands = tuple(doCommands)
else:
self.doCommands = (doCommands, )
if isinstance(undoCommands, (tuple, list)):
self.undoCommands = tuple(undoCommands)
else:
self.undoCommands = (undoCommands, )
class UndoStack(object):
def __init__(self, limit=2**15):
self.limit = limit
self.frozen = 0
self.clear()
def __stackAppend(self, stack, c):
stack.append(c)
while len(stack) > self.limit:
stack.pop(0)
def do(self, doCommands, undoCommands):
if self.frozen:
return
c = UndoCommand(doCommands, undoCommands)
self.__stackAppend(self.undoStack, c)
self.redoStack = []
def undo(self):
if not self.undoStack:
return None
c = self.undoStack.pop()
self.__stackAppend(self.redoStack, c)
return c
def redo(self):
if not self.redoStack:
return None
c = self.redoStack.pop()
self.__stackAppend(self.undoStack, c)
return c
def clear(self):
self.undoStack = []
self.redoStack = []
def freeze(self):
assert(self.frozen >= 0)
self.frozen += 1
def thaw(self):
self.frozen -= 1
assert(self.frozen >= 0)
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