from threading import Thread

from .terminate_process_on_failure import terminate_process_on_failure


class PipeReaderThread(Thread):
    _stop_sequence = b'stop_reading'

    def __init__(self, pipe_path, message_handler):
        super().__init__()
        self._message_handler = message_handler
        self._pipe_path = pipe_path

    @terminate_process_on_failure
    def run(self):
        while True:
            with open(self._pipe_path, 'rb') as pipe:
                message = pipe.read()
            if message == self._stop_sequence:
                break
            self._message_handler(message)

    def stop(self):
        with open(self._pipe_path, 'wb') as pipe:
            pipe.write(self._stop_sequence)
        self.join()