threadrunner.py

'''Taken from PySide 6 Tutorial at pythonguis.com'''

from PySide6.QtCore import QRunnable, Slot, Signal, QObject

import sys
import traceback


class WorkerSignals(QObject):
    '''
    Defines the signals available from a running worker thread.

    Supported signals are:

    finished
        No data

    error
        tuple (exctype, value, traceback.format_exc() )

    result
        object data returned from processing, anything

    progress
        int indicating % progress

    '''
    finished = Signal()
    error = Signal(tuple)
    result = Signal(object)
    progress = Signal(int)




class Worker(QRunnable):
    '''
    Worker thread

    Inherits from QRunnable to handler worker thread setup, signals and wrap-up.

    :param callback: The function callback to run on this worker thread. Supplied args and
                     kwargs will be passed through to the runner.
    :type callback: function
    :param args: Arguments to pass to the callback function
    :param kwargs: Keywords to pass to the callback function

    '''

    def __init__(self, fn, *args, **kwargs):
        super(Worker, self).__init__()

        # Store constructor arguments (re-used for processing)
        self.fn = fn
        self.args = args
        self.kwargs = kwargs
        self.signals = WorkerSignals()

        # Add the callback to our kwargs
        if not 'noprogress' in kwargs: #pass a kwarg called 'noprogress' with any value to suppress progress reporting callback
                                       # this is so that our worker can wrap functions that don't accept a 'progress_callback' kwarg
            self.kwargs['progress_callback'] = self.signals.progress
        else:
            del self.kwargs['noprogress']

    @Slot()
    def run(self):
        '''
        Initialise the runner function with passed args, kwargs.
        '''

        # Retrieve args/kwargs here; and fire processing using them
        try:
            result = self.fn(*self.args, **self.kwargs)
        except:
            traceback.print_exc()
            exctype, value = sys.exc_info()[:2]
            self.signals.error.emit((exctype, value, traceback.format_exc()))
        else:
            self.signals.result.emit(result)  # Return the result of the processing
        finally:
            self.signals.finished.emit()  # Done