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# PiTiVi , Non-linear video editor
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# Copyright (c) 2009, Alessandro Decina <alessandro.d@gmail.com>
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# This program is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (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 GNU
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# Lesser General Public License for more details.
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# You should have received a copy of the GNU Lesser General Public
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# License along with this program; if not, write to the
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# Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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# Boston, MA 02110-1301, USA.
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from pitivi.signalinterface import Signallable
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from pitivi.log.loggable import Loggable
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class UndoError(Exception):
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class UndoWrongStateError(UndoError):
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class UndoableAction(Signallable):
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raise NotImplementedError()
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raise NotImplementedError()
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class UndoableActionStack(UndoableAction):
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def __init__(self, action_group_name):
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self.action_group_name = action_group_name
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self.done_actions = []
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self.undone_actions = []
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def push(self, action):
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self.done_actions.append(action)
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def _runAction(self, action_list, method_name):
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for action in action_list[::-1]:
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method = getattr(action, method_name)
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self._runAction(self.undone_actions, "do")
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self.done_actions = self.undone_actions[::-1]
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self._runAction(self.done_actions, "undo")
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self.undone_actions = self.done_actions[::-1]
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actions = self.done_actions + self.undone_actions
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self.undone_actions = []
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self.done_actions = []
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self._runAction(actions, "clean")
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class UndoableActionLog(Signallable):
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"begin": ["stack", "nested"],
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"push": ["stack", "action"],
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"rollback": ["stack", "nested"],
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"commit": ["stack", "nested"],
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self.undo_stacks = []
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self.redo_stacks = []
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self._checkpoint = self._takeSnapshot()
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def begin(self, action_group_name):
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stack = UndoableActionStack(action_group_name)
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nested = self._stackIsNested(stack)
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self.stacks.append(stack)
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self.emit("begin", stack, nested)
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def push(self, action):
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stack = self._getTopmostStack()
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except UndoWrongStateError:
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self.emit("push", stack, action)
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stack = self._getTopmostStack(pop=True)
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nested = self._stackIsNested(stack)
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self.emit("rollback", stack, nested)
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stack = self._getTopmostStack(pop=True)
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nested = self._stackIsNested(stack)
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self.undo_stacks.append(stack)
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self.stacks[-1].push(stack)
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self.redo_stacks = []
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self.emit("commit", stack, nested)
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if self.stacks or not self.undo_stacks:
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raise UndoWrongStateError()
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stack = self.undo_stacks.pop(-1)
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self._runStack(stack, stack.undo)
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self.redo_stacks.append(stack)
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self.emit("undo", stack)
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if self.stacks or not self.redo_stacks:
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raise UndoWrongStateError()
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stack = self.redo_stacks.pop(-1)
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self._runStack(stack, stack.do)
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self.undo_stacks.append(stack)
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self.emit("redo", stack)
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stacks = self.redo_stacks + self.undo_stacks
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self.redo_stacks = []
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self.undo_stacks = []
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self._runStack(stack, stack.clean)
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def _takeSnapshot(self):
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return list(self.undo_stacks)
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def checkpoint(self):
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raise UndoWrongStateError()
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self._checkpoint = self._takeSnapshot()
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current_snapshot = self._takeSnapshot()
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return current_snapshot != self._checkpoint
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def _runStack(self, stack, run):
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def _getTopmostStack(self, pop=False):
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stack = self.stacks.pop(-1)
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stack = self.stacks[-1]
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raise UndoWrongStateError()
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def _stackIsNested(self, stack):
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return bool(len(self.stacks))
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class DebugActionLogObserver(Loggable):
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def startObserving(self, log):
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self._connectToActionLog(log)
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def stopObserving(self, log):
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self._disconnectFromActionLog(log)
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def _connectToActionLog(self, log):
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log.connect("begin", self._actionLogBeginCb)
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log.connect("commit", self._actionLogCommitCb)
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log.connect("rollback", self._actionLogRollbackCb)
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log.connect("push", self._actionLogPushCb)
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def _disconnectFromActionLog(self, log):
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for method in (self._actionLogBeginCb, self._actionLogCommitCb,
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self._actionLogrollbackCb, self._actionLogPushCb):
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log.disconnect_by_func(method)
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def _actionLogBeginCb(self, log, stack, nested):
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self.debug("begin action %s nested %s",
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stack.action_group_name, nested)
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def _actionLogCommitCb(self, log, stack, nested):
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self.debug("commit action %s nested %s",
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stack.action_group_name, nested)
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def _actionLogRollbackCb(self, log, stack, nested):
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self.debug("rollback action %s nested %s",
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stack.action_group_name, nested)
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def _actionLogPushCb(self, log, stack, action):
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self.debug("push %s in %s", action, stack.action_group_name)
added
removed
pitivi/undo.py
