128 lines
3.3 KiB
Python
128 lines
3.3 KiB
Python
#-------------------------------------------------------------------------
|
|
#
|
|
# Standard python modules
|
|
#
|
|
#-------------------------------------------------------------------------
|
|
from abc import ABCMeta, abstractmethod
|
|
import time
|
|
from collections import deque
|
|
|
|
class DbUndo(metaclass=ABCMeta):
|
|
"""
|
|
Base class for the Gramps undo/redo manager. Needs to be subclassed
|
|
for use with a real backend.
|
|
"""
|
|
|
|
__slots__ = ('undodb', 'db', 'undo_history_timestamp', 'undoq', 'redoq')
|
|
|
|
def __init__(self, db):
|
|
"""
|
|
Class constructor. Set up main instance variables
|
|
"""
|
|
self.db = db
|
|
self.undoq = deque()
|
|
self.redoq = deque()
|
|
self.undo_history_timestamp = time.time()
|
|
|
|
def clear(self):
|
|
"""
|
|
Clear the undo/redo list (but not the backing storage)
|
|
"""
|
|
self.undoq.clear()
|
|
self.redoq.clear()
|
|
self.undo_history_timestamp = time.time()
|
|
|
|
def __enter__(self, value):
|
|
"""
|
|
Context manager method to establish the context
|
|
"""
|
|
self.open(value)
|
|
return self
|
|
|
|
def __exit__(self, exc_type, exc_val, exc_tb):
|
|
"""
|
|
Context manager method to finish the context
|
|
"""
|
|
if exc_type is None:
|
|
self.close()
|
|
return exc_type is None
|
|
|
|
@abstractmethod
|
|
def open(self, value):
|
|
"""
|
|
Open the backing storage. Needs to be overridden in the derived
|
|
class.
|
|
"""
|
|
|
|
@abstractmethod
|
|
def close(self):
|
|
"""
|
|
Close the backing storage. Needs to be overridden in the derived
|
|
class.
|
|
"""
|
|
|
|
@abstractmethod
|
|
def append(self, value):
|
|
"""
|
|
Add a new entry on the end. Needs to be overridden in the derived
|
|
class.
|
|
"""
|
|
|
|
@abstractmethod
|
|
def __getitem__(self, index):
|
|
"""
|
|
Returns an entry by index number. Needs to be overridden in the
|
|
derived class.
|
|
"""
|
|
|
|
@abstractmethod
|
|
def __setitem__(self, index, value):
|
|
"""
|
|
Set an entry to a value. Needs to be overridden in the derived class.
|
|
"""
|
|
|
|
@abstractmethod
|
|
def __len__(self):
|
|
"""
|
|
Returns the number of entries. Needs to be overridden in the derived
|
|
class.
|
|
"""
|
|
|
|
@abstractmethod
|
|
def _redo(self, update_history):
|
|
"""
|
|
"""
|
|
|
|
@abstractmethod
|
|
def _undo(self, update_history):
|
|
"""
|
|
"""
|
|
|
|
def commit(self, txn, msg):
|
|
"""
|
|
Commit the transaction to the undo/redo database. "txn" should be
|
|
an instance of Gramps transaction class
|
|
"""
|
|
txn.set_description(msg)
|
|
txn.timestamp = time.time()
|
|
self.undoq.append(txn)
|
|
|
|
def undo(self, update_history=True):
|
|
"""
|
|
Undo a previously committed transaction
|
|
"""
|
|
if self.db.readonly or self.undo_count == 0:
|
|
return False
|
|
return self._undo(update_history)
|
|
|
|
def redo(self, update_history=True):
|
|
"""
|
|
Redo a previously committed, then undone, transaction
|
|
"""
|
|
if self.db.readonly or self.redo_count == 0:
|
|
return False
|
|
return self._redo(update_history)
|
|
|
|
undo_count = property(lambda self:len(self.undoq))
|
|
redo_count = property(lambda self:len(self.redoq))
|