openlp/openlp/core/threading.py

# -*- coding: utf-8 -*-
# vim: autoindent shiftwidth=4 expandtab textwidth=120 tabstop=4 softtabstop=4

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# OpenLP - Open Source Lyrics Projection                                      #
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# Copyright (c) 2008-2017 OpenLP Developers                                   #
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# This program is free software; you can redistribute it and/or modify it     #
# under the terms of the GNU General Public License as published by the Free  #
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"""
The :mod:`openlp.core.threading` module contains some common threading code
"""
from PyQt5 import QtCore


def run_thread(parent, worker, prefix='', auto_start=True):
    """
    Create a thread and assign a worker to it. This removes a lot of boilerplate code from the codebase.

    :param object parent: The parent object so that the thread and worker are not orphaned.
    :param QObject worker: A QObject-based worker object which does the actual work.
    :param str prefix: A prefix to be applied to the attribute names.
    :param bool auto_start: Automatically start the thread. Defaults to True.
    """
    # Set up attribute names
    thread_name = 'thread'
    worker_name = 'worker'
    if prefix:
        thread_name = '_'.join([prefix, thread_name])
        worker_name = '_'.join([prefix, worker_name])
    # Create the thread and add the thread and the worker to the parent
    thread = QtCore.QThread()
    setattr(parent, thread_name, thread)
    setattr(parent, worker_name, worker)
    # Move the worker into the thread's context
    worker.moveToThread(thread)
    # Connect slots and signals
    thread.started.connect(worker.start)
    worker.quit.connect(thread.quit)
    worker.quit.connect(worker.deleteLater)
    thread.finished.connect(thread.deleteLater)
    if auto_start:
        thread.start()