Agordejo/engine/jackclient.py

#! /usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Copyright 2022, Nils Hilbricht, Germany ( https://www.hilbricht.net )

This file is part of the Laborejo Software Suite ( https://www.laborejo.org ),

This 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 Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""

import logging; logger = logging.getLogger(__name__); logger.info("import")

#Standard Library
import atexit
import sys

#Third Party
import engine.jacklib as jacklib
from ctypes import pointer

#Our Modules
from engine.config import METADATA  #includes METADATA only. No other environmental setup is executed.
from engine.jacklib.helpers import get_jack_status_error_string

class AgordejoJackClient(object):
    """Singleton. Created in api.startEngine.
    If client cannot be started the program will exit from here.
    Most error sources are already ruled out in start.py."""

    def __init__(self):
        status = jacklib.jack_status_t()
        self._jacklibClient = jacklib.client_open(METADATA["name"], jacklib.JackNoStartServer, status)
        err = get_jack_status_error_string(status)

        if not status.value == 0:
            #Decide if a name collision is important or not. Agordejo cannot be started two times anyway. So this would be another client called Agordejo?
            if status.value & jacklib.JackNameNotUnique:
                logger.warning(f"Another JACK client called {METADATA['name']} exist. We will rename ourselve, but this is most likely a real problem. Agordejo is not supposed to be started twice. Please investigate!")
            else:
                logger.error("JackClient error: " + status.value)
                sys.exit(0) #atexit will trigger

        atexit.register(lambda c=self._jacklibClient: jacklib.client_close(c))

        #Callbacks. They are mirrored by the api Callbacks without the callback_ prefix so a GUI can directly access them.
        #However, they are mutable lists. And we define all actual callback-sender here. the api calls them via our Object/Instance
        self.callback_setPlaybackSeconds = []

    def _setPlaybackSeconds(self):
        """Added to the fast event loop. Therefore called VERY often.
        Yes, this is not a super accurate function because while we iterate transport already progresses"""
        pos = jacklib.jack_position_t() #pos._fields_
        state = jacklib.transport_query(self._jacklibClient, pointer(pos)) #this actually sets the pos and info. We need this, even if we don't use "state" here.
        #if not pos.frame_rate:
        #    return
        currenTimeInSeconds = round(pos.frame / pos.frame_rate, 8)
        for func in self.callback_setPlaybackSeconds:
            func(currenTimeInSeconds, not state == jacklib.JackTransportStopped) #current time in seconds and if playback is running

    #Public API. Called via api.jackClient.rewind()
    def _seek(self, frame:int):
        jacklib.transport_locate(self._jacklibClient, frame)

    def seek(self, seconds):
        pos = jacklib.jack_position_t()
        state = jacklib.transport_query(self._jacklibClient, pointer(pos)) #this actually sets the pos and info. We need this, even if we don't use "state" here.
        self._seek(int(seconds * pos.frame_rate))

    def rewind(self):
        self._seek(0)

    def playPause(self):
        pos = jacklib.jack_position_t() #pos._fields_
        state = jacklib.transport_query(self._jacklibClient, pointer(pos))
        if state == jacklib.JackTransportStopped:
            jacklib.transport_start(self._jacklibClient)
        elif state == jacklib.JackTransportStarting:
            pass
        else:
            jacklib.transport_stop(self._jacklibClient)