def signal_wakeup(app):
"""
Allow to be notified in python for signals when in long-running calls from
the C or c++ side, like QApplication.exec_().
See https://stackoverflow.com/a/37229299.
"""
sock = QAbstractSocket(QAbstractSocket.UdpSocket, app)
# Create a socket pair
sock.wsock, sock.rsock = socket.socketpair(type=socket.SOCK_DGRAM)
# Let Qt listen on the one end
sock.setSocketDescriptor(sock.rsock.fileno())
# And let Python write on the other end
sock.wsock.setblocking(False)
signal.set_wakeup_fd(sock.wsock.fileno())
# add a dummy callback just to be on the python side as soon as possible.
sock.readyRead.connect(lambda: None)
def disable_nagle(socket: QAbstractSocket) -> None:
# http://doc.qt.io/qt-5/qabstractsocket.html#SocketOption-enum
socket.setSocketOption(QAbstractSocket.LowDelayOption, 1)
def get_socket_error(socket: QAbstractSocket) -> str:
return "{}: {}".format(socket.error(), socket.errorString())
def is_socket_connected(socket: QAbstractSocket) -> bool:
return socket and socket.state() == QAbstractSocket.ConnectedState