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[ui.utils] makeProperty: destroyCallback mechanism for QObject-type properties

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allow to be warned when the underlying value of a QObject-type property has been destroyed and react to this
This commit is contained in:
Yann Lanthony 2018-12-06 15:28:17 +01:00
parent 2e06ad1b83
commit 9534e75552
1 changed files with 16 additions and 6 deletions
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22
meshroom/ui/utils.py
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@ -1,8 +1,9 @@
import os
import time
from PySide2.QtCore import QFileSystemWatcher, QUrl, Slot, QTimer, Property
from PySide2.QtCore import QFileSystemWatcher, QUrl, Slot, QTimer, Property, QObject
from PySide2.QtQml import QQmlApplicationEngine
from PySide2 import shiboken2
class QmlInstantEngine(QQmlApplicationEngine):
@ -193,7 +194,7 @@ class QmlInstantEngine(QQmlApplicationEngine):
self.load(self._sourceFile)
def makeProperty(T, attributeName, notify=None):
def makeProperty(T, attributeName, notify=None, destroyCallback=None):
"""
Shortcut function to create a Qt Property with generic getter and setter.
@ -204,6 +205,8 @@ def makeProperty(T, attributeName, notify=None):
T (type): the type of the property
attributeName (str): the name of underlying instance attribute to get/set
notify (Signal): the notify signal; if None, property will be constant
destroyCallback (function): (optional) Function to call when value gets destroyed.
Only applicable for QObject-type properties.
Examples:
class Foo(QObject):
@ -217,12 +220,17 @@ def makeProperty(T, attributeName, notify=None):
Returns:
Property: the created Property
"""
def setter(instance, value, notifyName):
def setter(instance, value):
""" Generic setter. """
if getattr(instance, attributeName) == value:
currentValue = getattr(instance, attributeName)
if currentValue == value:
return
if destroyCallback and currentValue and shiboken2.isValid(currentValue):
currentValue.destroyed.disconnect(destroyCallback)
setattr(instance, attributeName, value)
getattr(instance, notifyName).emit()
if destroyCallback and value:
value.destroyed.connect(destroyCallback)
getattr(instance, signalName(notify)).emit()
def getter(instance):
""" Generic getter. """
@ -233,7 +241,9 @@ def makeProperty(T, attributeName, notify=None):
# string representation contains trailing '()', remove it
return str(signalInstance)[:-2]
if destroyCallback and not issubclass(T, QObject):
raise RuntimeError("destroyCallback can only be used with QObject-type properties.")
if notify:
return Property(T, getter, lambda self, value: setter(self, value, signalName(notify)), notify=notify)
return Property(T, getter, setter, notify=notify)
else:
return Property(T, getter, constant=True)