aeidon/agents/register.py¶
Source code for module aeidon.agents.register from file aeidon/agents/register.py.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 | # -*- coding: utf-8 -*-
# Copyright (C) 2005 Osmo Salomaa
#
# This program 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 3 of the License, or
# (at your option) any later version.
#
# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
"""
Managing revertable actions.
To hook a method up with the undo/redo system, the following need to be done:
(1) The last argument to the method must be a keyword argument `register` with
a default value of -1. This argument indicates which of doing, undoing or
redoing is in process.
(2) At the end of the method, :meth:`register_action` needs to be called with
an instance of :class:`aeidon.RevertableAction`. Calling this method takes
care of the management of undo and redo stacks.
(3) The method should be marked with the :func:`aeidon.deco.revertable`
decorator. This decorator takes care of emitting an action signal once
the method has been run, cuts the undo and redo stacks if needed and
defaults the `register` keyword argument to :attr:`aeidon.registers.DO`.
Each method marked as revertable should match exactly one action in the undo
and redo stacks. Hence, if a method calls other revertable methods, the
resulting action needs to be grouped as one using :meth:`group_actions`.
If a revertable method needs to be performed without the possibility of
reverting, the `register` keyword argument should be given a value of ``None``.
This way it will not be in any way processed by the undo/redo system.
"""
import aeidon
class RegisterAgent(aeidon.Delegate):
"""
Managing revertable actions.
:ivar _do_description: Original description of the action
"""
def __init__(self, master):
"""Initialize a :class:`RegisterAgent` instance."""
aeidon.Delegate.__init__(self, master)
self._do_description = None
aeidon.util.connect(self, self, "notify::undo_limit")
def _break_action_group(self, stack, index=0):
"""Break the action group in `stack` and return amount broken into."""
action_group = stack.pop(index)
for action in reversed(action_group.actions):
stack.insert(index, action)
return len(action_group.actions)
@aeidon.deco.export
def can_redo(self, count=1):
"""Return ``True`` if one or more actions can be redone."""
return len(self.redoables) >= count
@aeidon.deco.export
def can_undo(self, count=1):
"""Return ``True`` if one or more actions can be undone."""
return len(self.undoables) >= count
@aeidon.deco.export
def cut_reversion_stacks(self):
"""Cut undo and redo stacks to their maximum lengths."""
if self.undo_limit is not None:
del self.redoables[self.undo_limit:]
del self.undoables[self.undo_limit:]
@aeidon.deco.export
def emit_action_signal(self, register):
"""Emit an action signal for the most recent registered action."""
if register is not None:
self.emit(register.signal,
self._get_destination_stack(register)[0])
def _get_destination_stack(self, register):
"""Return the stack where the registered action will be placed."""
if register.shift == 1:
return self.undoables
if register.shift == -1:
return self.redoables
raise ValueError("Invalid register: {}"
.format(repr(register)))
def _get_source_stack(self, register):
"""Return the stack where the action to register is taken from."""
if register.shift == 1:
return self.redoables
if register.shift == -1:
return self.undoables
raise ValueError("Invalid register: {}"
.format(repr(register)))
@aeidon.deco.export
def group_actions(self, register, count, description):
"""Group the registered actions as one item in the stack."""
if register is None: return
action_group = aeidon.RevertableActionGroup()
action_group.actions = []
action_group.description = description
stack = self._get_destination_stack(register)
for i in range(count):
action = stack.pop(0)
if isinstance(action, aeidon.RevertableActionGroup):
action_group.actions.extend(action.actions)
else: # Single action
action_group.actions.append(action)
stack.insert(0, action_group)
def _on_notify_undo_limit(self, *args):
"""Cut reversion stacks if limit set."""
if self.undo_limit is not None:
self.cut_reversion_stacks()
@aeidon.deco.export
def redo(self, count=1):
"""Redo `count` amount of actions from the redoable stack."""
group = aeidon.RevertableActionGroup
if count > 1 or isinstance(self.redoables[0], group):
return self._revert_multiple(count, aeidon.registers.REDO)
self._do_description = self.redoables[0].description
self.redoables.pop(0).revert()
@aeidon.deco.export
def register_action(self, action):
"""Register `action` as done, undone or redone."""
if action.register == aeidon.registers.DO:
self.undoables.insert(0, action)
self.redoables = []
self._shift_changed_value(action, action.register.shift)
if action.register == aeidon.registers.UNDO:
self.redoables.insert(0, action)
action.description = self._do_description
self._shift_changed_value(action, action.register.shift)
if action.register == aeidon.registers.REDO:
self.undoables.insert(0, action)
action.description = self._do_description
self._shift_changed_value(action, action.register.shift)
def _revert_multiple(self, count, register):
"""Revert multiple actions."""
self.block(register.signal)
stack = self._get_source_stack(register)
for i in range(count):
part_count = 1
if isinstance(stack[0], aeidon.RevertableActionGroup):
description = stack[0].description
part_count = self._break_action_group(stack)
for j in range(part_count):
self._do_description = stack[0].description
stack.pop(0).revert()
if part_count > 1:
self.group_actions(register, part_count, description)
self.unblock(register.signal)
self.cut_reversion_stacks()
self.emit_action_signal(register)
@aeidon.deco.export
def set_action_description(self, register, description):
"""Set the description of the most recent registered action."""
if register is None: return
stack = self._get_destination_stack(register)
stack[0].description = description
def _shift_changed_value(self, action, shift):
"""Shift the values of changed attributes."""
if aeidon.documents.MAIN in action.docs:
self.main_changed += shift
if tuple(action.docs) == (aeidon.documents.TRAN,):
# Make translation document active.
if self.tran_changed is None:
self.tran_changed = 0
if aeidon.documents.TRAN in action.docs:
if self.tran_changed is not None:
self.tran_changed += shift
@aeidon.deco.export
def undo(self, count=1):
"""Undo `count` amount of actions from the undoable stack."""
group = aeidon.RevertableActionGroup
if (count > 1) or isinstance(self.undoables[0], group):
return self._revert_multiple(count, aeidon.registers.UNDO)
self._do_description = self.undoables[0].description
self.undoables.pop(0).revert()
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