109 lines
3.5 KiB
Python
109 lines
3.5 KiB
Python
'''
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Copyright (C) 2023 CG Cookie
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http://cgcookie.com
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hello@cgcookie.com
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Created by Jonathan Denning, Jonathan Williamson, and Patrick Moore
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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'''
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from collections import namedtuple
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class UndoStack:
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def __init__(self, fn_create_state, fn_restore_state, *, max_size=100):
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self._fn_step = namedtuple('UndoStep', 'key repeatable state')
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self._fn_create = fn_create_state
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self._fn_restore = fn_restore_state
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self._max_size = max_size
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self.clear()
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def _pop(self, *, undo=True):
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stack = (self._undo if undo else self._redo)
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return stack.pop()
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def _restore(self, step, *args, **kwargs):
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self._fn_restore(step.state, *args, **kwargs)
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def _push_step(self, key, *, repeatable=False, undo=True, clear=True):
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step = self._fn_step(key, repeatable, self._fn_create(key))
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if undo:
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self._undo.append(step)
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if clear:
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self._redo.clear()
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# limit stack size
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while len(self._undo) > self._max_size:
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self._undo.pop(0)
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else:
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self._redo.append(step)
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def _is_empty(self, *, undo=True):
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return not bool(self._undo if undo else self._redo)
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def keys(self, *, undo=True):
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stack = reversed(self._undo if undo else self._redo)
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return [step.key for step in stack]
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def _top(self, *, undo=True):
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stack = (self._undo if undo else self._redo)
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return stack[-1] if stack else None
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def top_key(self, *, undo=True):
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top = self._top(undo=undo)
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return top.key if top else None
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def clear(self):
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self._undo = []
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self._redo = []
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self._changes = 0
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@property
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def changes(self):
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return self._changes
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def push(self, key, *, repeatable=False):
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# skip pushing to undo if action is repeatable and we are repeating actions
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top = self._top()
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if repeatable and top and top.repeatable and top.key == key: return
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self._push_step(key, repeatable=repeatable)
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self._changes += 1
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def pop(self, *args, undo=True, **kwargs):
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if self._is_empty(undo=undo): return
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key = 'undo' if undo else 'redo'
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self._push_step(key, undo=not undo, clear=undo)
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step = self._pop(undo=undo)
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self._restore(step, *args, **kwargs)
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self._changes += 1
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#### the following code is not working??
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# def restore(self, *args, **kwargs):
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# if self._is_empty(): return
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# step = self._top()
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# self._restore(step, *args, **kwargs)
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# self._redo.clear()
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# self._changes += 1
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def cancel(self, *args, **kwargs):
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if self._is_empty(): return
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step = self._pop()
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self._restore(step, *args, **kwargs)
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self._changes += 1
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def break_repeatable(self):
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if self._is_empty(): return
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self._top().repeatable = False
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