def connect_to_signal(signal: pyqtSignal, callbacks):
if not callbacks:
return
if callable(callbacks):
callbacks = [callbacks]
for callback in callbacks:
signal.connect(callback)
def connect(signal: pyqtSignal, callback: Callable):
"""
By default calling ``signal.connect(callback)`` will dispose of context information.
Practically, this leads to single line tracebacks when ``signal.emit()`` is invoked.
This is very hard to debug.
This function wraps the ``connect()`` call to give you additional traceback information, if the callback does crash.
:param signal: the signal to ``connect()`` to.
:param callback: the callback to connect (will be called after ``signal.emit(...)``.
"""
# Step 1: At time of calling this function: get the stack frames.
# We reconstruct the stack as a ``traceback`` object.
source = None
for frame in list(inspect.stack())[1:]:
source = types.TracebackType(source, frame.frame, frame.index or 0,
frame.lineno)
# Step 2: construct a lightweight StackSummary object which does not contain
# actual frames or locals, to avoid memory leak
try:
summary = traceback.StackSummary.extract(traceback.walk_tb(source),
capture_locals=False)
finally:
del source
# Step 3: Wrap the ``callback`` and inject our creation stack if an error occurs.
# The BaseException instead of Exception is intentional: this makes sure interrupts of infinite loops show
# the source callback stack for debugging.
def trackback_wrapper(*args, **kwargs):
try:
callback(*args, **kwargs)
except BaseException as exc:
traceback_str = '\n' + ''.join(summary.format())
raise exc from CreationTraceback(traceback_str)
try:
setattr(callback, "tb_wrapper", trackback_wrapper)
except AttributeError:
# This is not a free function, but either an external library or a method bound to an instance.
if not hasattr(callback, "tb_wrapper") and hasattr(
callback, "__self__") and hasattr(callback, "__func__"):
# methods are finicky: you can't set attributes on them.
# Instead, we inject the handlers for each method in a dictionary on the instance.
bound_obj = callback.__self__
if not hasattr(bound_obj, "tb_mapping"):
setattr(bound_obj, "tb_mapping", {})
bound_obj.tb_mapping[
callback.__func__.__name__] = trackback_wrapper
else:
logging.warning(
"Unable to hook up connect() info to %s. Probably a 'builtin_function_or_method'.",
repr(callback))
# Step 3: Connect our wrapper to the signal.
signal.connect(trackback_wrapper)
def __init__(self,
conditions: List[SelectionCondition],
control: QWidget,
signal: pyqtSignal,
action: Callable,
activate_action: Callable = None,
deactivate_action: Callable = None,
model_change_handler: Callable = None):
self.__conditions = conditions
self.__control = control
self.__action = action
self.__activate_action = activate_action
self.__deactivate_action = deactivate_action
self.__model_change_handler = model_change_handler
signal.connect(lambda *args: action(self._selection, *args))
self.update_selection([])
def __init__(self, settings: Settings, db: DB, on_create: Callable,
on_date_click: Callable, tasks_changed_event: qtc.pyqtSignal,
factory: TaskWidgetFactory):
super().__init__()
tasks_changed_event.connect(self._redraw_tasks)
self._db = db
self._factory = factory
self._settings = settings
main_layout = qtw.QVBoxLayout()
self.setLayout(main_layout)
self._current_date = date.today()
self._date_button = qtw.QPushButton(clicked=on_date_click)
font = self._date_button.font()
font.setPixelSize(20)
self._date_button.setFont(font)
self._update_date_label()
tasks_scroll_area = qtw.QScrollArea(widgetResizable=True)
tasks_scroll_area_content = qtw.QWidget()
tasks_scroll_area.setWidget(tasks_scroll_area_content)
self._tasks_layout = qtw.QVBoxLayout(tasks_scroll_area_content)
self._tasks_layout.setAlignment(qtc.Qt.AlignTop)
self._prev_day_button = qtw.QPushButton(
text=settings.PREVIOUS_DAY_BUTTON_TEXT,
clicked=lambda: self._change_day(-1))
self._create_task_button = qtw.QPushButton(
text=settings.CREATE_TASK_BUTTON_TEXT, clicked=on_create)
self._next_day_button = qtw.QPushButton(
text=settings.NEXT_DAY_BUTTON_TEXT,
clicked=lambda: self._change_day(1))
buttons_layout = qtw.QHBoxLayout()
buttons_layout.addWidget(self._prev_day_button)
buttons_layout.addWidget(self._create_task_button)
buttons_layout.addWidget(self._next_day_button)
main_layout.addWidget(self._date_button)
main_layout.addWidget(tasks_scroll_area)
main_layout.addLayout(buttons_layout)
def is_connected(signal: pyqtSignal, slot: pyqtSlot) -> bool:
"""
Determine if a (bound) signal is connected to a slot.
:param signal: signal (a return value from a call to pyqtSignal(...))
:param slot: slot (a method on a QObject, decorated with pyqtSlot)
:return: True if connected, False otherwise
"""
try:
signal.connect(slot, Qt.UniqueConnection)
except TypeError as exc:
assert str(exc) in (
'connection is not unique',
'connect() failed between MyObj.sig_test[] and meth()')
return True
else:
signal.disconnect(slot)
return False