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# coding: utf-8
# /*##########################################################################
#
# Copyright (C) 2016-2018 European Synchrotron Radiation Facility
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# ###########################################################################*/
__authors__ = ["V. Valls"]
__license__ = "MIT"
__date__ = "16/10/2020"
import contextlib
from silx.gui import qt
class AbstractModel(qt.QObject):
changed = qt.Signal()
def __init__(self, parent=None):
qt.QObject.__init__(self, parent)
self.__isLocked = 0
self.__wasChanged = False
def isValid(self):
return True
def wasChanged(self):
"""Emit the change event in case of the model was not locked.
:returns: True if the signal was emitted.
"""
if self.__isLocked > 0:
self.__wasChanged = True
return False
else:
self.changed.emit()
return True
def isLocked(self):
"""Returns True if the events are locked.
:rtype: bool
"""
return self.__isLocked > 0
@contextlib.contextmanager
def lockContext(self):
"""Context manager to lock and unlock signals."""
self.lockSignals()
yield self
self.unlockSignals()
def lockSignals(self):
"""Lock the change events
"""
self.__isLocked = self.__isLocked + 1
def unlockSignals(self):
"""Unlock the change events
:returns: False if the model is still locked, else True
"""
assert self.__isLocked > 0
self.__isLocked = self.__isLocked - 1
if self.__isLocked == 0 and self.__wasChanged:
self.__wasChanged = False
self.wasChanged()
return self.__isLocked == 0
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